From 3565071f226432336a54d0193d729fa4508a3394 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:28:00 +0200 Subject: Adding debian version 6.6.15-2. Signed-off-by: Daniel Baumann --- ...-ARM-vfp-Provide-vfp_lock-for-VFP-locking.patch | 75 ++ ...0001-arm-Disable-jump-label-on-PREEMPT_RT.patch | 36 + ...play-Remove-migrate_en-dis-from-dc_fpu_be.patch | 86 +++ ...ched-Constrain-locks-in-sched_submit_work.patch | 49 ++ ...Provide-a-method-to-check-if-a-task-is-PI.patch | 54 ++ ...proper-comment-about-the-preempt-disable-.patch | 47 ++ ...-ARM-vfp-Use-vfp_lock-in-vfp_sync_hwstate.patch | 44 ++ ...rm-amd-display-Simplify-the-per-CPU-usage.patch | 127 ++++ ...utex-Avoid-unconditional-slowpath-for-DEB.patch | 79 +++ .../0002-serial-core-Use-lock-wrappers.patch | 93 +++ ...t-disable-preemption-in-ptrace_stop-on-PR.patch | 48 ++ ...-Add-function-to-preempt-serving-softirqs.patch | 60 ++ ...ARM-vfp-Use-vfp_lock-in-vfp_support_entry.patch | 48 ++ ...play-Add-a-warning-if-the-FPU-is-used-out.patch | 26 + ...e-preempt_disable-enable_rt-where-recomme.patch | 56 ++ .../0003-sched-Extract-__schedule_loop.patch | 58 ++ .../0003-serial-21285-Use-port-lock-wrappers.patch | 75 ++ ...03-time-Allow-to-preempt-after-a-callback.patch | 47 ++ ...e-sending-signals-outside-of-vfp_lock-ed-.patch | 121 ++++ ...play-Move-the-memory-allocation-out-of-dc.patch | 87 +++ ...n-t-disable-interrupts-on-PREEMPT_RT-duri.patch | 85 +++ ...ovide-rt_mutex-specific-scheduler-helpers.patch | 128 ++++ ...-8250_aspeed_vuart-Use-port-lock-wrappers.patch | 61 ++ ...play-Move-the-memory-allocation-out-of-dc.patch | 121 ++++ ...n-t-check-for-atomic-context-on-PREEMPT_R.patch | 30 + ...utex-Use-rt_mutex-specific-scheduler-help.patch | 177 +++++ ...erial-8250_bcm7271-Use-port-lock-wrappers.patch | 151 ++++ ...i915-Disable-tracing-points-on-PREEMPT_RT.patch | 45 ++ ...utex-Add-a-lockdep-assert-to-catch-potent.patch | 57 ++ .../0006-serial-8250-Use-port-lock-wrappers.patch | 465 ++++++++++++ ...ip-DRM_I915_LOW_LEVEL_TRACEPOINTS-with-NO.patch | 29 + ...ex-pi-Fix-recursive-rt_mutex-waiter-state.patch | 198 ++++++ ...07-serial-8250_dma-Use-port-lock-wrappers.patch | 80 +++ ...5-gt-Queue-and-wait-for-the-irq_work-item.patch | 42 ++ ...008-serial-8250_dw-Use-port-lock-wrappers.patch | 69 ++ ...-Use-spin_lock_irq-instead-of-local_irq_d.patch | 89 +++ ...9-serial-8250_exar-Use-port-lock-wrappers.patch | 52 ++ ...010-drm-i915-Drop-the-irqs_disabled-check.patch | 39 ++ ...10-serial-8250_fsl-Use-port-lock-wrappers.patch | 63 ++ ...11-serial-8250_mtk-Use-port-lock-wrappers.patch | 77 ++ ...2-serial-8250_omap-Use-port-lock-wrappers.patch | 236 +++++++ ...rial-8250_pci1xxxx-Use-port-lock-wrappers.patch | 66 ++ ...al-altera_jtaguart-Use-port-lock-wrappers.patch | 133 ++++ ...serial-altera_uart-Use-port-lock-wrappers.patch | 116 +++ ...-serial-amba-pl010-Use-port-lock-wrappers.patch | 112 +++ ...-serial-amba-pl011-Use-port-lock-wrappers.patch | 327 +++++++++ .../0018-serial-apb-Use-port-lock-wrappers.patch | 76 ++ ...0019-serial-ar933x-Use-port-lock-wrappers.patch | 144 ++++ ...20-serial-arc_uart-Use-port-lock-wrappers.patch | 97 +++ .../0021-serial-atmel-Use-port-lock-wrappers.patch | 119 ++++ ...erial-bcm63xx-uart-Use-port-lock-wrappers.patch | 128 ++++ ...23-serial-cpm_uart-Use-port-lock-wrappers.patch | 70 ++ ...4-serial-digicolor-Use-port-lock-wrappers.patch | 113 +++ .../0025-serial-dz-Use-port-lock-wrappers.patch | 161 +++++ ...serial-linflexuart-Use-port-lock-wrappers.patch | 143 ++++ ...-serial-fsl_lpuart-Use-port-lock-wrappers.patch | 389 ++++++++++ .../0028-serial-icom-Use-port-lock-wrappers.patch | 151 ++++ .../0029-serial-imx-Use-port-lock-wrappers.patch | 354 ++++++++++ ...0-serial-ip22zilog-Use-port-lock-wrappers.patch | 185 +++++ .../0031-serial-jsm-Use-port-lock-wrappers.patch | 124 ++++ ...32-serial-liteuart-Use-port-lock-wrappers.patch | 110 +++ ...-serial-lpc32xx_hs-Use-port-lock-wrappers.patch | 148 ++++ ...0034-serial-ma35d1-Use-port-lock-wrappers.patch | 117 ++++ .../0035-serial-mcf-Use-port-lock-wrappers.patch | 127 ++++ ...rial-men_z135_uart-Use-port-lock-wrappers.patch | 76 ++ .../0037-serial-meson-Use-port-lock-wrappers.patch | 168 +++++ ...rial-milbeaut_usio-Use-port-lock-wrappers.patch | 101 +++ ...039-serial-mpc52xx-Use-port-lock-wrappers.patch | 89 +++ ...0-serial-mps2-uart-Use-port-lock-wrappers.patch | 103 +++ .../0041-serial-msm-Use-port-lock-wrappers.patch | 185 +++++ ...-serial-mvebu-uart-Use-port-lock-wrappers.patch | 108 +++ .../0043-serial-omap-Use-port-lock-wrappers.patch | 180 +++++ .../0044-serial-owl-Use-port-lock-wrappers.patch | 147 ++++ .../0045-serial-pch-Use-port-lock-wrappers.patch | 80 +++ .../0046-serial-pic32-Use-port-lock-wrappers.patch | 118 ++++ ...-serial-pmac_zilog-Use-port-lock-wrappers.patch | 232 ++++++ .../0048-serial-pxa-Use-port-lock-wrappers.patch | 150 ++++ ...9-serial-qcom-geni-Use-port-lock-wrappers.patch | 71 ++ .../0050-serial-rda-Use-port-lock-wrappers.patch | 177 +++++ .../0051-serial-rp2-Use-port-lock-wrappers.patch | 114 +++ ...0052-serial-sa1100-Use-port-lock-wrappers.patch | 117 ++++ ...serial-samsung_tty-Use-port-lock-wrappers.patch | 245 +++++++ ...erial-sb1250-duart-Use-port-lock-wrappers.patch | 85 +++ .../0056-serial-tegra-Use-port-lock-wrappers.patch | 176 +++++ .../0057-serial-core-Use-port-lock-wrappers.patch | 365 ++++++++++ ...-serial-mctrl_gpio-Use-port-lock-wrappers.patch | 58 ++ .../0059-serial-txx9-Use-port-lock-wrappers.patch | 134 ++++ ...0060-serial-sh-sci-Use-port-lock-wrappers.patch | 302 ++++++++ ...0061-serial-sifive-Use-port-lock-wrappers.patch | 102 +++ .../0062-serial-sprd-Use-port-lock-wrappers.patch | 162 +++++ ...0063-serial-st-asc-Use-port-lock-wrappers.patch | 110 +++ .../0064-serial-stm32-Use-port-lock-wrappers.patch | 184 +++++ .../0065-serial-sunhv-Use-port-lock-wrappers.patch | 149 ++++ ...erial-sunplus-uart-Use-port-lock-wrappers.patch | 146 ++++ ...0067-serial-sunsab-Use-port-lock-wrappers.patch | 176 +++++ .../0068-serial-sunsu-Use-port-lock-wrappers.patch | 219 ++++++ ...69-serial-sunzilog-Use-port-lock-wrappers.patch | 211 ++++++ ...70-serial-timbuart-Use-port-lock-wrappers.patch | 71 ++ ...71-serial-uartlite-Use-port-lock-wrappers.patch | 105 +++ ...72-serial-ucc_uart-Use-port-lock-wrappers.patch | 59 ++ ...0073-serial-vt8500-Use-port-lock-wrappers.patch | 76 ++ ...rial-xilinx_uartps-Use-port-lock-wrappers.patch | 276 ++++++++ ...non-BKL-nbcon-console-basic-infrastructur.patch | 261 +++++++ ...76-printk-nbcon-Add-acquire-release-logic.patch | 705 +++++++++++++++++++ ...-static-printk-buffers-available-to-nbcon.patch | 65 ++ .../0078-printk-nbcon-Add-buffer-management.patch | 311 ++++++++ ...rintk-nbcon-Add-ownership-state-functions.patch | 179 +++++ .../0080-printk-nbcon-Add-sequence-handling.patch | 311 ++++++++ ...n-Add-emit-function-and-callback-function.patch | 262 +++++++ ...n-Allow-drivers-to-mark-unsafe-regions-an.patch | 136 ++++ ...ix-illegal-pbufs-access-for-CONFIG_PRINTK.patch | 134 ++++ .../0084-printk-Reduce-pr_flush-pooling-time.patch | 102 +++ ...85-printk-nbcon-Relocate-32bit-seq-macros.patch | 141 ++++ ...rintk-Adjust-mapping-for-32bit-seq-macros.patch | 71 ++ ...prb_first_seq-as-base-for-32bit-seq-macro.patch | 71 ++ ...buffer-Do-not-skip-non-finalized-records-.patch | 304 ++++++++ ...tk-ringbuffer-Clarify-special-lpos-values.patch | 92 +++ ...suppress_panic_printk-check-for-other-CPU.patch | 34 + .../0091-printk-Add-this_cpu_in_panic.patch | 88 +++ ...ntk-ringbuffer-Cleanup-reader-terminology.patch | 67 ++ ...it-for-all-reserved-records-with-pr_flush.patch | 170 +++++ ...buffer-Skip-non-finalized-records-in-pani.patch | 68 ++ ...buffer-Consider-committed-as-finalized-in.patch | 62 ++ ...ble-passing-console-lock-owner-completely.patch | 107 +++ ...void-non-panic-CPUs-writing-to-ringbuffer.patch | 78 +++ ...-panic-Flush-kernel-log-buffer-at-the-end.patch | 38 + ...-Consider-nbcon-boot-consoles-on-seq-init.patch | 51 ++ ...d-sparse-notation-to-console_srcu-locking.patch | 36 + ...n-Ensure-ownership-release-on-failed-emit.patch | 58 ++ ...k-Check-printk_deferred_enter-_exit-usage.patch | 58 ++ ...n-Implement-processing-in-port-lock-wrapp.patch | 244 +++++++ ...n-Add-driver_enter-driver_exit-console-ca.patch | 42 ++ ...Make-console_is_usable-available-to-nbcon.patch | 103 +++ ...printk-Let-console_is_usable-handle-nbcon.patch | 43 ++ ...-Add-flags-argument-for-console_is_usable.patch | 67 ++ ...n-Provide-function-to-flush-using-write_a.patch | 186 +++++ ...109-printk-Track-registered-boot-consoles.patch | 78 +++ ...n-Use-nbcon-consoles-in-console_flush_all.patch | 173 +++++ ...-nbcon-Assign-priority-based-on-CPU-state.patch | 113 +++ ...printk-nbcon-Add-unsafe-flushing-on-panic.patch | 96 +++ ...d-console_lock-dance-if-no-legacy-or-boot.patch | 211 ++++++ .../0114-printk-Track-nbcon-consoles.patch | 67 ++ ...rintk-Coordinate-direct-printing-in-panic.patch | 134 ++++ ...printk-nbcon-Implement-emergency-sections.patch | 232 ++++++ ...0117-panic-Mark-emergency-section-in-warn.patch | 38 + ...0118-panic-Mark-emergency-section-in-oops.patch | 39 ++ ...-rcu-Mark-emergency-section-in-rcu-stalls.patch | 45 ++ ...-Mark-emergency-section-in-lockdep-splats.patch | 45 ++ ...-printk-nbcon-Introduce-printing-kthreads.patch | 441 ++++++++++++ ...tomic-print-in-printk-context-on-shutdown.patch | 41 ++ ...tk-nbcon-Add-context-to-console_is_usable.patch | 111 +++ ...4-printk-nbcon-Add-printer-thread-wakeups.patch | 164 +++++ ...ntk-nbcon-Stop-threads-on-shutdown-reboot.patch | 60 ++ .../0126-printk-nbcon-Start-printing-threads.patch | 135 ++++ ...-proc-Add-nbcon-support-for-proc-consoles.patch | 53 ++ ...28-tty-sysfs-Add-nbcon-support-for-active.patch | 33 + ...n-Provide-function-to-reacquire-ownership.patch | 92 +++ ...-Provide-low-level-functions-to-port-lock.patch | 43 ++ .../0131-serial-8250-Switch-to-nbcon-console.patch | 335 +++++++++ ...rintk-Add-kthread-for-all-legacy-consoles.patch | 422 +++++++++++ ...-revert-drop-lockdep-annotation-from-seri.patch | 29 + ...d-false-positive-lockdep-report-for-legac.patch | 64 ++ debian/patches-rt/ARM64__Allow_to_enable_RT.patch | 27 + debian/patches-rt/ARM__Allow_to_enable_RT.patch | 35 + ...slation_section_permission_fault_handlers.patch | 91 +++ .../Add_localversion_for_-RT_release.patch | 19 + .../patches-rt/POWERPC__Allow_to_enable_RT.patch | 35 + debian/patches-rt/PREEMPT_AUTO.patch | 779 +++++++++++++++++++++ ...Probe-misaligned-access-speed-in-parallel.patch | 197 ++++++ .../Revert-drm-i915-Depend-on-PREEMPT_RT.patch | 23 + ...i915-Do-not-disable-preemption-for-resets.patch | 99 +++ ...-guc-Consider-also-RCU-depth-in-busy-loop.patch | 29 + .../patches-rt/net-Avoid-the-IPI-to-free-the.patch | 119 ++++ ...eries-Select-the-generic-memory-allocator.patch | 27 + .../powerpc__traps__Use_PREEMPT_RT.patch | 38 + ...e_in-kernel_MPIC_emulation_for_PREEMPT_RT.patch | 43 ++ ...u__Use_a_locallock_instead_local_irq_save.patch | 115 +++ ..._work_around_stack-guard_init_from_atomic.patch | 37 + ...-preempt_enable-within-an-instrumentation.patch | 47 ++ ...Also-force-sched-priority-to-timersd-on-b.patch | 71 ++ .../riscv-add-PREEMPT_AUTO-support.patch | 44 ++ debian/patches-rt/riscv-allow-to-enable-RT.patch | 23 + ...rt-Don-t-try-push-tasks-if-there-are-none.patch | 58 ++ debian/patches-rt/series | 255 +++++++ ...-Use-a-dedicated-thread-for-timer-wakeups.patch | 222 ++++++ ...ftirq-Wake-ktimers-thread-also-in-softirq.patch | 44 ++ .../sysfs__Add__sys_kernel_realtime_entry.patch | 53 ++ ...timer-storm-since-introduction-of-timersd.patch | 106 +++ ...ty_serial_omap__Make_the_locking_RT_aware.patch | 47 ++ ...serial_pl011__Make_the_locking_work_on_RT.patch | 46 ++ debian/patches-rt/x86__Allow_to_enable_RT.patch | 27 + .../patches-rt/x86__Enable_RT_also_on_32bit.patch | 33 + ...e-bit-spinlocks-with-spinlock_t-for-PREEM.patch | 94 +++ 193 files changed, 23669 insertions(+) create mode 100644 debian/patches-rt/0001-ARM-vfp-Provide-vfp_lock-for-VFP-locking.patch create mode 100644 debian/patches-rt/0001-arm-Disable-jump-label-on-PREEMPT_RT.patch create mode 100644 debian/patches-rt/0001-drm-amd-display-Remove-migrate_en-dis-from-dc_fpu_be.patch create mode 100644 debian/patches-rt/0001-sched-Constrain-locks-in-sched_submit_work.patch create mode 100644 debian/patches-rt/0001-sched-core-Provide-a-method-to-check-if-a-task-is-PI.patch create mode 100644 debian/patches-rt/0001-signal-Add-proper-comment-about-the-preempt-disable-.patch create mode 100644 debian/patches-rt/0002-ARM-vfp-Use-vfp_lock-in-vfp_sync_hwstate.patch create mode 100644 debian/patches-rt/0002-drm-amd-display-Simplify-the-per-CPU-usage.patch create mode 100644 debian/patches-rt/0002-locking-rtmutex-Avoid-unconditional-slowpath-for-DEB.patch create mode 100644 debian/patches-rt/0002-serial-core-Use-lock-wrappers.patch create mode 100644 debian/patches-rt/0002-signal-Don-t-disable-preemption-in-ptrace_stop-on-PR.patch create mode 100644 debian/patches-rt/0002-softirq-Add-function-to-preempt-serving-softirqs.patch create mode 100644 debian/patches-rt/0003-ARM-vfp-Use-vfp_lock-in-vfp_support_entry.patch create mode 100644 debian/patches-rt/0003-drm-amd-display-Add-a-warning-if-the-FPU-is-used-out.patch create mode 100644 debian/patches-rt/0003-drm-i915-Use-preempt_disable-enable_rt-where-recomme.patch create mode 100644 debian/patches-rt/0003-sched-Extract-__schedule_loop.patch create mode 100644 debian/patches-rt/0003-serial-21285-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0003-time-Allow-to-preempt-after-a-callback.patch create mode 100644 debian/patches-rt/0004-ARM-vfp-Move-sending-signals-outside-of-vfp_lock-ed-.patch create mode 100644 debian/patches-rt/0004-drm-amd-display-Move-the-memory-allocation-out-of-dc.patch create mode 100644 debian/patches-rt/0004-drm-i915-Don-t-disable-interrupts-on-PREEMPT_RT-duri.patch create mode 100644 debian/patches-rt/0004-sched-Provide-rt_mutex-specific-scheduler-helpers.patch create mode 100644 debian/patches-rt/0004-serial-8250_aspeed_vuart-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0005-drm-amd-display-Move-the-memory-allocation-out-of-dc.patch create mode 100644 debian/patches-rt/0005-drm-i915-Don-t-check-for-atomic-context-on-PREEMPT_R.patch create mode 100644 debian/patches-rt/0005-locking-rtmutex-Use-rt_mutex-specific-scheduler-help.patch create mode 100644 debian/patches-rt/0005-serial-8250_bcm7271-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0006-drm-i915-Disable-tracing-points-on-PREEMPT_RT.patch create mode 100644 debian/patches-rt/0006-locking-rtmutex-Add-a-lockdep-assert-to-catch-potent.patch create mode 100644 debian/patches-rt/0006-serial-8250-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0007-drm-i915-skip-DRM_I915_LOW_LEVEL_TRACEPOINTS-with-NO.patch create mode 100644 debian/patches-rt/0007-futex-pi-Fix-recursive-rt_mutex-waiter-state.patch create mode 100644 debian/patches-rt/0007-serial-8250_dma-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0008-drm-i915-gt-Queue-and-wait-for-the-irq_work-item.patch create mode 100644 debian/patches-rt/0008-serial-8250_dw-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0009-drm-i915-gt-Use-spin_lock_irq-instead-of-local_irq_d.patch create mode 100644 debian/patches-rt/0009-serial-8250_exar-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0010-drm-i915-Drop-the-irqs_disabled-check.patch create mode 100644 debian/patches-rt/0010-serial-8250_fsl-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0011-serial-8250_mtk-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0012-serial-8250_omap-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0013-serial-8250_pci1xxxx-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0014-serial-altera_jtaguart-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0015-serial-altera_uart-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0016-serial-amba-pl010-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0017-serial-amba-pl011-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0018-serial-apb-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0019-serial-ar933x-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0020-serial-arc_uart-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0021-serial-atmel-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0022-serial-bcm63xx-uart-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0023-serial-cpm_uart-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0024-serial-digicolor-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0025-serial-dz-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0026-serial-linflexuart-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0027-serial-fsl_lpuart-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0028-serial-icom-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0029-serial-imx-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0030-serial-ip22zilog-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0031-serial-jsm-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0032-serial-liteuart-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0033-serial-lpc32xx_hs-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0034-serial-ma35d1-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0035-serial-mcf-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0036-serial-men_z135_uart-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0037-serial-meson-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0038-serial-milbeaut_usio-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0039-serial-mpc52xx-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0040-serial-mps2-uart-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0041-serial-msm-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0042-serial-mvebu-uart-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0043-serial-omap-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0044-serial-owl-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0045-serial-pch-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0046-serial-pic32-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0047-serial-pmac_zilog-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0048-serial-pxa-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0049-serial-qcom-geni-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0050-serial-rda-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0051-serial-rp2-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0052-serial-sa1100-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0053-serial-samsung_tty-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0054-serial-sb1250-duart-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0056-serial-tegra-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0057-serial-core-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0058-serial-mctrl_gpio-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0059-serial-txx9-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0060-serial-sh-sci-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0061-serial-sifive-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0062-serial-sprd-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0063-serial-st-asc-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0064-serial-stm32-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0065-serial-sunhv-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0066-serial-sunplus-uart-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0067-serial-sunsab-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0068-serial-sunsu-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0069-serial-sunzilog-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0070-serial-timbuart-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0071-serial-uartlite-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0072-serial-ucc_uart-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0073-serial-vt8500-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0074-serial-xilinx_uartps-Use-port-lock-wrappers.patch create mode 100644 debian/patches-rt/0075-printk-Add-non-BKL-nbcon-console-basic-infrastructur.patch create mode 100644 debian/patches-rt/0076-printk-nbcon-Add-acquire-release-logic.patch create mode 100644 debian/patches-rt/0077-printk-Make-static-printk-buffers-available-to-nbcon.patch create mode 100644 debian/patches-rt/0078-printk-nbcon-Add-buffer-management.patch create mode 100644 debian/patches-rt/0079-printk-nbcon-Add-ownership-state-functions.patch create mode 100644 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100644 debian/patches-rt/0132-printk-Add-kthread-for-all-legacy-consoles.patch create mode 100644 debian/patches-rt/0133-serial-8250-revert-drop-lockdep-annotation-from-seri.patch create mode 100644 debian/patches-rt/0134-printk-Avoid-false-positive-lockdep-report-for-legac.patch create mode 100644 debian/patches-rt/ARM64__Allow_to_enable_RT.patch create mode 100644 debian/patches-rt/ARM__Allow_to_enable_RT.patch create mode 100644 debian/patches-rt/ARM__enable_irq_in_translation_section_permission_fault_handlers.patch create mode 100644 debian/patches-rt/Add_localversion_for_-RT_release.patch create mode 100644 debian/patches-rt/POWERPC__Allow_to_enable_RT.patch create mode 100644 debian/patches-rt/PREEMPT_AUTO.patch create mode 100644 debian/patches-rt/RISC-V-Probe-misaligned-access-speed-in-parallel.patch create mode 100644 debian/patches-rt/Revert-drm-i915-Depend-on-PREEMPT_RT.patch create mode 100644 debian/patches-rt/drm-i915-Do-not-disable-preemption-for-resets.patch create mode 100644 debian/patches-rt/drm-i915-guc-Consider-also-RCU-depth-in-busy-loop.patch create mode 100644 debian/patches-rt/net-Avoid-the-IPI-to-free-the.patch create mode 100644 debian/patches-rt/powerpc-pseries-Select-the-generic-memory-allocator.patch create mode 100644 debian/patches-rt/powerpc__traps__Use_PREEMPT_RT.patch create mode 100644 debian/patches-rt/powerpc_kvm__Disable_in-kernel_MPIC_emulation_for_PREEMPT_RT.patch create mode 100644 debian/patches-rt/powerpc_pseries_iommu__Use_a_locallock_instead_local_irq_save.patch create mode 100644 debian/patches-rt/powerpc_stackprotector__work_around_stack-guard_init_from_atomic.patch create mode 100644 debian/patches-rt/preempt-Put-preempt_enable-within-an-instrumentation.patch create mode 100644 debian/patches-rt/rcutorture-Also-force-sched-priority-to-timersd-on-b.patch create mode 100644 debian/patches-rt/riscv-add-PREEMPT_AUTO-support.patch create mode 100644 debian/patches-rt/riscv-allow-to-enable-RT.patch create mode 100644 debian/patches-rt/sched-rt-Don-t-try-push-tasks-if-there-are-none.patch create mode 100644 debian/patches-rt/series create mode 100644 debian/patches-rt/softirq-Use-a-dedicated-thread-for-timer-wakeups.patch create mode 100644 debian/patches-rt/softirq-Wake-ktimers-thread-also-in-softirq.patch create mode 100644 debian/patches-rt/sysfs__Add__sys_kernel_realtime_entry.patch create mode 100644 debian/patches-rt/tick-Fix-timer-storm-since-introduction-of-timersd.patch create mode 100644 debian/patches-rt/tty_serial_omap__Make_the_locking_RT_aware.patch create mode 100644 debian/patches-rt/tty_serial_pl011__Make_the_locking_work_on_RT.patch create mode 100644 debian/patches-rt/x86__Allow_to_enable_RT.patch create mode 100644 debian/patches-rt/x86__Enable_RT_also_on_32bit.patch create mode 100644 debian/patches-rt/zram-Replace-bit-spinlocks-with-spinlock_t-for-PREEM.patch (limited to 'debian/patches-rt') diff --git a/debian/patches-rt/0001-ARM-vfp-Provide-vfp_lock-for-VFP-locking.patch b/debian/patches-rt/0001-ARM-vfp-Provide-vfp_lock-for-VFP-locking.patch new file mode 100644 index 000000000..03eb551db --- /dev/null +++ b/debian/patches-rt/0001-ARM-vfp-Provide-vfp_lock-for-VFP-locking.patch @@ -0,0 +1,75 @@ +From: Sebastian Andrzej Siewior +Date: Fri, 19 May 2023 16:57:29 +0200 +Subject: [PATCH 1/4] ARM: vfp: Provide vfp_lock() for VFP locking. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +kernel_neon_begin() uses local_bh_disable() to ensure exclusive access +to the VFP unit. This is broken on PREEMPT_RT because a BH disabled +section remains preemptible on PREEMPT_RT. + +Introduce vfp_lock() which uses local_bh_disable() and preempt_disable() +on PREEMPT_RT. Since softirqs are processed always in thread context, +disabling preemption is enough to ensure that the current context won't +get interrupted by something that is using the VFP. Use it in +kernel_neon_begin(). + +Signed-off-by: Sebastian Andrzej Siewior +--- + arch/arm/vfp/vfpmodule.c | 32 ++++++++++++++++++++++++++++++-- + 1 file changed, 30 insertions(+), 2 deletions(-) + +--- a/arch/arm/vfp/vfpmodule.c ++++ b/arch/arm/vfp/vfpmodule.c +@@ -56,6 +56,34 @@ extern unsigned int VFP_arch_feroceon __ + union vfp_state *vfp_current_hw_state[NR_CPUS]; + + /* ++ * Claim ownership of the VFP unit. ++ * ++ * The caller may change VFP registers until vfp_unlock() is called. ++ * ++ * local_bh_disable() is used to disable preemption and to disable VFP ++ * processing in softirq context. On PREEMPT_RT kernels local_bh_disable() is ++ * not sufficient because it only serializes soft interrupt related sections ++ * via a local lock, but stays preemptible. Disabling preemption is the right ++ * choice here as bottom half processing is always in thread context on RT ++ * kernels so it implicitly prevents bottom half processing as well. ++ */ ++static void vfp_lock(void) ++{ ++ if (!IS_ENABLED(CONFIG_PREEMPT_RT)) ++ local_bh_disable(); ++ else ++ preempt_disable(); ++} ++ ++static void vfp_unlock(void) ++{ ++ if (!IS_ENABLED(CONFIG_PREEMPT_RT)) ++ local_bh_enable(); ++ else ++ preempt_enable(); ++} ++ ++/* + * Is 'thread's most up to date state stored in this CPUs hardware? + * Must be called from non-preemptible context. + */ +@@ -819,7 +847,7 @@ void kernel_neon_begin(void) + unsigned int cpu; + u32 fpexc; + +- local_bh_disable(); ++ vfp_lock(); + + /* + * Kernel mode NEON is only allowed outside of hardirq context with +@@ -850,7 +878,7 @@ void kernel_neon_end(void) + { + /* Disable the NEON/VFP unit. */ + fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_EN); +- local_bh_enable(); ++ vfp_unlock(); + } + EXPORT_SYMBOL(kernel_neon_end); + diff --git a/debian/patches-rt/0001-arm-Disable-jump-label-on-PREEMPT_RT.patch b/debian/patches-rt/0001-arm-Disable-jump-label-on-PREEMPT_RT.patch new file mode 100644 index 000000000..5c8c179ae --- /dev/null +++ b/debian/patches-rt/0001-arm-Disable-jump-label-on-PREEMPT_RT.patch @@ -0,0 +1,36 @@ +From: Thomas Gleixner +Date: Wed, 8 Jul 2015 17:14:48 +0200 +Subject: [PATCH 1/2] arm: Disable jump-label on PREEMPT_RT. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +jump-labels are used to efficiently switch between two possible code +paths. To achieve this, stop_machine() is used to keep the CPU in a +known state while the opcode is modified. The usage of stop_machine() +here leads to large latency spikes which can be observed on PREEMPT_RT. + +Jump labels may change the target during runtime and are not restricted +to debug or "configuration/ setup" part of a PREEMPT_RT system where +high latencies could be defined as acceptable. + +Disable jump-label support on a PREEMPT_RT system. + +[bigeasy: Patch description.] + +Signed-off-by: Thomas Gleixner +Signed-off-by: Sebastian Andrzej Siewior +Link: https://lkml.kernel.org/r/20220613182447.112191-2-bigeasy@linutronix.de +--- + arch/arm/Kconfig | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +--- a/arch/arm/Kconfig ++++ b/arch/arm/Kconfig +@@ -73,7 +73,7 @@ config ARM + select HAS_IOPORT + select HAVE_ARCH_AUDITSYSCALL if AEABI && !OABI_COMPAT + select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6 +- select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU ++ select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU && !PREEMPT_RT + select HAVE_ARCH_KFENCE if MMU && !XIP_KERNEL + select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU + select HAVE_ARCH_KASAN if MMU && !XIP_KERNEL diff --git a/debian/patches-rt/0001-drm-amd-display-Remove-migrate_en-dis-from-dc_fpu_be.patch b/debian/patches-rt/0001-drm-amd-display-Remove-migrate_en-dis-from-dc_fpu_be.patch new file mode 100644 index 000000000..b78f988da --- /dev/null +++ b/debian/patches-rt/0001-drm-amd-display-Remove-migrate_en-dis-from-dc_fpu_be.patch @@ -0,0 +1,86 @@ +From: Sebastian Andrzej Siewior +Date: Thu, 21 Sep 2023 16:15:12 +0200 +Subject: [PATCH 1/5] drm/amd/display: Remove migrate_en/dis from + dc_fpu_begin(). +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +This is a revert of the commit mentioned below while it is not wrong, as +in the kernel will explode, having migrate_disable() here it is +complete waste of resources. + +Additionally commit message is plain wrong the review tag does not make +it any better. The migrate_disable() interface has a fat comment +describing it and it includes the word "undesired" in the headline which +should tickle people to read it before using it. +Initially I assumed it is worded too harsh but now I beg to differ. + +The reviewer of the original commit, even not understanding what +migrate_disable() does should ask the following: + +- migrate_disable() is added only to the CONFIG_X86 block and it claims + to protect fpu_recursion_depth. Why are the other the architectures + excluded? + +- migrate_disable() is added after fpu_recursion_depth was modified. + Shouldn't it be added before the modification or referencing takes + place? + +Moving on. +Disabling preemption DOES prevent CPU migration. A task, that can not be +pushed away from the CPU by the scheduler (due to disabled preemption) +can not be pushed or migrated to another CPU. + +Disabling migration DOES NOT ensure consistency of per-CPU variables. It +only ensures that the task acts always on the same per-CPU variable. The +task remains preemptible meaning multiple tasks can access the same +per-CPU variable. This in turn leads to inconsistency for the statement + + *pcpu -= 1; + +with two tasks on one CPU and a preemption point during the RMW +operation: + + Task A Task B + read pcpu to reg # 0 + inc reg # 0 -> 1 + read pcpu to reg # 0 + inc reg # 0 -> 1 + write reg to pcpu # 1 + write reg to pcpu # 1 + +At the end pcpu reads 1 but should read 2 instead. Boom. + +get_cpu_ptr() already contains a preempt_disable() statement. That means +that the per-CPU variable can only be referenced by a single task which +is currently running. The only inconsistency that can occur if the +variable is additionally accessed from an interrupt. + +Remove migrate_disable/enable() from dc_fpu_begin/end(). + +Cc: Tianci Yin +Cc: Aurabindo Pillai +Fixes: 0c316556d1249 ("drm/amd/display: Disable migration to ensure consistency of per-CPU variable") +Link: https://lore.kernel.org/r/20230921141516.520471-2-bigeasy@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c | 2 -- + 1 file changed, 2 deletions(-) + +--- a/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c ++++ b/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c +@@ -91,7 +91,6 @@ void dc_fpu_begin(const char *function_n + + if (*pcpu == 1) { + #if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH) +- migrate_disable(); + kernel_fpu_begin(); + #elif defined(CONFIG_PPC64) + if (cpu_has_feature(CPU_FTR_VSX_COMP)) { +@@ -132,7 +131,6 @@ void dc_fpu_end(const char *function_nam + if (*pcpu <= 0) { + #if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH) + kernel_fpu_end(); +- migrate_enable(); + #elif defined(CONFIG_PPC64) + if (cpu_has_feature(CPU_FTR_VSX_COMP)) { + disable_kernel_vsx(); diff --git a/debian/patches-rt/0001-sched-Constrain-locks-in-sched_submit_work.patch b/debian/patches-rt/0001-sched-Constrain-locks-in-sched_submit_work.patch new file mode 100644 index 000000000..73828f0ef --- /dev/null +++ b/debian/patches-rt/0001-sched-Constrain-locks-in-sched_submit_work.patch @@ -0,0 +1,49 @@ +From: Peter Zijlstra +Date: Fri, 8 Sep 2023 18:22:48 +0200 +Subject: [PATCH 1/7] sched: Constrain locks in sched_submit_work() +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Even though sched_submit_work() is ran from preemptible context, +it is discouraged to have it use blocking locks due to the recursion +potential. + +Enforce this. + +Signed-off-by: Peter Zijlstra (Intel) +Signed-off-by: Sebastian Andrzej Siewior +Signed-off-by: Peter Zijlstra (Intel) +Link: https://lkml.kernel.org/r/20230908162254.999499-2-bigeasy@linutronix.de +--- + kernel/sched/core.c | 9 +++++++++ + 1 file changed, 9 insertions(+) + +--- a/kernel/sched/core.c ++++ b/kernel/sched/core.c +@@ -6721,11 +6721,18 @@ void __noreturn do_task_dead(void) + + static inline void sched_submit_work(struct task_struct *tsk) + { ++ static DEFINE_WAIT_OVERRIDE_MAP(sched_map, LD_WAIT_CONFIG); + unsigned int task_flags; + + if (task_is_running(tsk)) + return; + ++ /* ++ * Establish LD_WAIT_CONFIG context to ensure none of the code called ++ * will use a blocking primitive -- which would lead to recursion. ++ */ ++ lock_map_acquire_try(&sched_map); ++ + task_flags = tsk->flags; + /* + * If a worker goes to sleep, notify and ask workqueue whether it +@@ -6750,6 +6757,8 @@ static inline void sched_submit_work(str + * make sure to submit it to avoid deadlocks. + */ + blk_flush_plug(tsk->plug, true); ++ ++ lock_map_release(&sched_map); + } + + static void sched_update_worker(struct task_struct *tsk) diff --git a/debian/patches-rt/0001-sched-core-Provide-a-method-to-check-if-a-task-is-PI.patch b/debian/patches-rt/0001-sched-core-Provide-a-method-to-check-if-a-task-is-PI.patch new file mode 100644 index 000000000..35892558e --- /dev/null +++ b/debian/patches-rt/0001-sched-core-Provide-a-method-to-check-if-a-task-is-PI.patch @@ -0,0 +1,54 @@ +From: Sebastian Andrzej Siewior +Date: Fri, 4 Aug 2023 13:30:37 +0200 +Subject: [PATCH 1/3] sched/core: Provide a method to check if a task is + PI-boosted. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Provide a method to check if a task inherited the priority from another +task. This happens if a task owns a lock which is requested by a task +with higher priority. This can be used as a hint to add a preemption +point to the critical section. + +Provide a function which reports true if the task is PI-boosted. + +Link: https://lore.kernel.org/r/20230804113039.419794-2-bigeasy@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/sched.h | 1 + + kernel/sched/core.c | 15 +++++++++++++++ + 2 files changed, 16 insertions(+) + +--- a/include/linux/sched.h ++++ b/include/linux/sched.h +@@ -1905,6 +1905,7 @@ static inline int dl_task_check_affinity + } + #endif + ++extern bool task_is_pi_boosted(const struct task_struct *p); + extern int yield_to(struct task_struct *p, bool preempt); + extern void set_user_nice(struct task_struct *p, long nice); + extern int task_prio(const struct task_struct *p); +--- a/kernel/sched/core.c ++++ b/kernel/sched/core.c +@@ -8923,6 +8923,21 @@ static inline void preempt_dynamic_init( + + #endif /* #ifdef CONFIG_PREEMPT_DYNAMIC */ + ++/* ++ * task_is_pi_boosted - Check if task has been PI boosted. ++ * @p: Task to check. ++ * ++ * Return true if task is subject to priority inheritance. ++ */ ++bool task_is_pi_boosted(const struct task_struct *p) ++{ ++ int prio = p->prio; ++ ++ if (!rt_prio(prio)) ++ return false; ++ return prio != p->normal_prio; ++} ++ + /** + * yield - yield the current processor to other threads. + * diff --git a/debian/patches-rt/0001-signal-Add-proper-comment-about-the-preempt-disable-.patch b/debian/patches-rt/0001-signal-Add-proper-comment-about-the-preempt-disable-.patch new file mode 100644 index 000000000..e00261d79 --- /dev/null +++ b/debian/patches-rt/0001-signal-Add-proper-comment-about-the-preempt-disable-.patch @@ -0,0 +1,47 @@ +From: Sebastian Andrzej Siewior +Date: Thu, 3 Aug 2023 12:09:31 +0200 +Subject: [PATCH 1/2] signal: Add proper comment about the preempt-disable in + ptrace_stop(). +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Commit 53da1d9456fe7 ("fix ptrace slowness") added a preempt-disable section +between read_unlock() and the following schedule() invocation without +explaining why it is needed. + +Replace the comment with an explanation why this is needed. Clarify that +it is needed for correctness but for performance reasons. + +Acked-by: Oleg Nesterov +Signed-off-by: Sebastian Andrzej Siewior +Link: https://lore.kernel.org/r/20230803100932.325870-2-bigeasy@linutronix.de +--- + kernel/signal.c | 17 ++++++++++++++--- + 1 file changed, 14 insertions(+), 3 deletions(-) + +--- a/kernel/signal.c ++++ b/kernel/signal.c +@@ -2329,10 +2329,21 @@ static int ptrace_stop(int exit_code, in + do_notify_parent_cldstop(current, false, why); + + /* +- * Don't want to allow preemption here, because +- * sys_ptrace() needs this task to be inactive. ++ * The previous do_notify_parent_cldstop() invocation woke ptracer. ++ * One a PREEMPTION kernel this can result in preemption requirement ++ * which will be fulfilled after read_unlock() and the ptracer will be ++ * put on the CPU. ++ * The ptracer is in wait_task_inactive(, __TASK_TRACED) waiting for ++ * this task wait in schedule(). If this task gets preempted then it ++ * remains enqueued on the runqueue. The ptracer will observe this and ++ * then sleep for a delay of one HZ tick. In the meantime this task ++ * gets scheduled, enters schedule() and will wait for the ptracer. + * +- * XXX: implement read_unlock_no_resched(). ++ * This preemption point is not bad from correctness point of view but ++ * extends the runtime by one HZ tick time due to the ptracer's sleep. ++ * The preempt-disable section ensures that there will be no preemption ++ * between unlock and schedule() and so improving the performance since ++ * the ptracer has no reason to sleep. + */ + preempt_disable(); + read_unlock(&tasklist_lock); diff --git a/debian/patches-rt/0002-ARM-vfp-Use-vfp_lock-in-vfp_sync_hwstate.patch b/debian/patches-rt/0002-ARM-vfp-Use-vfp_lock-in-vfp_sync_hwstate.patch new file mode 100644 index 000000000..a0d93547c --- /dev/null +++ b/debian/patches-rt/0002-ARM-vfp-Use-vfp_lock-in-vfp_sync_hwstate.patch @@ -0,0 +1,44 @@ +From: Sebastian Andrzej Siewior +Date: Fri, 19 May 2023 16:57:30 +0200 +Subject: [PATCH 2/4] ARM: vfp: Use vfp_lock() in vfp_sync_hwstate(). +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +vfp_sync_hwstate() uses preempt_disable() followed by local_bh_disable() +to ensure that it won't get interrupted while checking the VFP state. +This harms PREEMPT_RT because softirq handling can get preempted and +local_bh_disable() synchronizes the related section with a sleeping lock +which does not work with disabled preemption. + +Use the vfp_lock() to synchronize the access. + +Signed-off-by: Sebastian Andrzej Siewior +--- + arch/arm/vfp/vfpmodule.c | 9 +++------ + 1 file changed, 3 insertions(+), 6 deletions(-) + +--- a/arch/arm/vfp/vfpmodule.c ++++ b/arch/arm/vfp/vfpmodule.c +@@ -540,11 +540,9 @@ static inline void vfp_pm_init(void) { } + */ + void vfp_sync_hwstate(struct thread_info *thread) + { +- unsigned int cpu = get_cpu(); ++ vfp_lock(); + +- local_bh_disable(); +- +- if (vfp_state_in_hw(cpu, thread)) { ++ if (vfp_state_in_hw(raw_smp_processor_id(), thread)) { + u32 fpexc = fmrx(FPEXC); + + /* +@@ -555,8 +553,7 @@ void vfp_sync_hwstate(struct thread_info + fmxr(FPEXC, fpexc); + } + +- local_bh_enable(); +- put_cpu(); ++ vfp_unlock(); + } + + /* Ensure that the thread reloads the hardware VFP state on the next use. */ diff --git a/debian/patches-rt/0002-drm-amd-display-Simplify-the-per-CPU-usage.patch b/debian/patches-rt/0002-drm-amd-display-Simplify-the-per-CPU-usage.patch new file mode 100644 index 000000000..fd18d53e2 --- /dev/null +++ b/debian/patches-rt/0002-drm-amd-display-Simplify-the-per-CPU-usage.patch @@ -0,0 +1,127 @@ +From: Sebastian Andrzej Siewior +Date: Thu, 21 Sep 2023 16:15:13 +0200 +Subject: [PATCH 2/5] drm/amd/display: Simplify the per-CPU usage. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +The fpu_recursion_depth counter is used to ensure that dc_fpu_begin() +can be invoked multiple times while the FPU-disable function itself is +only invoked once. Also the counter part (dc_fpu_end()) is ballanced +properly. + +Instead of using the get_cpu_ptr() dance around the inc it is simpler to +increment the per-CPU variable directly. Also the per-CPU variable has +to be incremented and decremented on the same CPU. This is ensured by +the inner-part which disables preemption. This is kind of not obvious, +works and the preempt-counter is touched a few times for no reason. + +Disable preemption before incrementing fpu_recursion_depth for the first +time. Keep preemption disabled until dc_fpu_end() where the counter is +decremented making it obvious that the preemption has to stay disabled +while the counter is non-zero. +Use simple inc/dec functions. +Remove the nested preempt_disable/enable functions which are now not +needed. + +Link: https://lore.kernel.org/r/20230921141516.520471-3-bigeasy@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c | 50 ++++++++++--------------- + 1 file changed, 20 insertions(+), 30 deletions(-) + +--- a/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c ++++ b/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c +@@ -60,11 +60,9 @@ static DEFINE_PER_CPU(int, fpu_recursion + */ + inline void dc_assert_fp_enabled(void) + { +- int *pcpu, depth = 0; ++ int depth; + +- pcpu = get_cpu_ptr(&fpu_recursion_depth); +- depth = *pcpu; +- put_cpu_ptr(&fpu_recursion_depth); ++ depth = __this_cpu_read(fpu_recursion_depth); + + ASSERT(depth >= 1); + } +@@ -84,32 +82,27 @@ inline void dc_assert_fp_enabled(void) + */ + void dc_fpu_begin(const char *function_name, const int line) + { +- int *pcpu; ++ int depth; + +- pcpu = get_cpu_ptr(&fpu_recursion_depth); +- *pcpu += 1; ++ preempt_disable(); ++ depth = __this_cpu_inc_return(fpu_recursion_depth); + +- if (*pcpu == 1) { ++ if (depth == 1) { + #if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH) + kernel_fpu_begin(); + #elif defined(CONFIG_PPC64) +- if (cpu_has_feature(CPU_FTR_VSX_COMP)) { +- preempt_disable(); ++ if (cpu_has_feature(CPU_FTR_VSX_COMP)) + enable_kernel_vsx(); +- } else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) { +- preempt_disable(); ++ else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) + enable_kernel_altivec(); +- } else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) { +- preempt_disable(); ++ else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) + enable_kernel_fp(); +- } + #elif defined(CONFIG_ARM64) + kernel_neon_begin(); + #endif + } + +- TRACE_DCN_FPU(true, function_name, line, *pcpu); +- put_cpu_ptr(&fpu_recursion_depth); ++ TRACE_DCN_FPU(true, function_name, line, depth); + } + + /** +@@ -124,29 +117,26 @@ void dc_fpu_begin(const char *function_n + */ + void dc_fpu_end(const char *function_name, const int line) + { +- int *pcpu; ++ int depth; + +- pcpu = get_cpu_ptr(&fpu_recursion_depth); +- *pcpu -= 1; +- if (*pcpu <= 0) { ++ depth = __this_cpu_dec_return(fpu_recursion_depth); ++ if (depth == 0) { + #if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH) + kernel_fpu_end(); + #elif defined(CONFIG_PPC64) +- if (cpu_has_feature(CPU_FTR_VSX_COMP)) { ++ if (cpu_has_feature(CPU_FTR_VSX_COMP)) + disable_kernel_vsx(); +- preempt_enable(); +- } else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) { ++ else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) + disable_kernel_altivec(); +- preempt_enable(); +- } else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) { ++ else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) + disable_kernel_fp(); +- preempt_enable(); +- } + #elif defined(CONFIG_ARM64) + kernel_neon_end(); + #endif ++ } else { ++ WARN_ON_ONCE(depth < 0); + } + +- TRACE_DCN_FPU(false, function_name, line, *pcpu); +- put_cpu_ptr(&fpu_recursion_depth); ++ TRACE_DCN_FPU(false, function_name, line, depth); ++ preempt_enable(); + } diff --git a/debian/patches-rt/0002-locking-rtmutex-Avoid-unconditional-slowpath-for-DEB.patch b/debian/patches-rt/0002-locking-rtmutex-Avoid-unconditional-slowpath-for-DEB.patch new file mode 100644 index 000000000..561d5891b --- /dev/null +++ b/debian/patches-rt/0002-locking-rtmutex-Avoid-unconditional-slowpath-for-DEB.patch @@ -0,0 +1,79 @@ +From: Sebastian Andrzej Siewior +Date: Fri, 8 Sep 2023 18:22:49 +0200 +Subject: [PATCH 2/7] locking/rtmutex: Avoid unconditional slowpath for + DEBUG_RT_MUTEXES +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +With DEBUG_RT_MUTEXES enabled the fast-path rt_mutex_cmpxchg_acquire() +always fails and all lock operations take the slow path. + +Provide a new helper inline rt_mutex_try_acquire() which maps to +rt_mutex_cmpxchg_acquire() in the non-debug case. For the debug case +it invokes rt_mutex_slowtrylock() which can acquire a non-contended +rtmutex under full debug coverage. + +Signed-off-by: Sebastian Andrzej Siewior +Signed-off-by: Thomas Gleixner +Signed-off-by: Sebastian Andrzej Siewior +Signed-off-by: Peter Zijlstra (Intel) +Link: https://lkml.kernel.org/r/20230908162254.999499-3-bigeasy@linutronix.de +--- + kernel/locking/rtmutex.c | 21 ++++++++++++++++++++- + kernel/locking/ww_rt_mutex.c | 2 +- + 2 files changed, 21 insertions(+), 2 deletions(-) + +--- a/kernel/locking/rtmutex.c ++++ b/kernel/locking/rtmutex.c +@@ -218,6 +218,11 @@ static __always_inline bool rt_mutex_cmp + return try_cmpxchg_acquire(&lock->owner, &old, new); + } + ++static __always_inline bool rt_mutex_try_acquire(struct rt_mutex_base *lock) ++{ ++ return rt_mutex_cmpxchg_acquire(lock, NULL, current); ++} ++ + static __always_inline bool rt_mutex_cmpxchg_release(struct rt_mutex_base *lock, + struct task_struct *old, + struct task_struct *new) +@@ -297,6 +302,20 @@ static __always_inline bool rt_mutex_cmp + + } + ++static int __sched rt_mutex_slowtrylock(struct rt_mutex_base *lock); ++ ++static __always_inline bool rt_mutex_try_acquire(struct rt_mutex_base *lock) ++{ ++ /* ++ * With debug enabled rt_mutex_cmpxchg trylock() will always fail. ++ * ++ * Avoid unconditionally taking the slow path by using ++ * rt_mutex_slow_trylock() which is covered by the debug code and can ++ * acquire a non-contended rtmutex. ++ */ ++ return rt_mutex_slowtrylock(lock); ++} ++ + static __always_inline bool rt_mutex_cmpxchg_release(struct rt_mutex_base *lock, + struct task_struct *old, + struct task_struct *new) +@@ -1755,7 +1774,7 @@ static int __sched rt_mutex_slowlock(str + static __always_inline int __rt_mutex_lock(struct rt_mutex_base *lock, + unsigned int state) + { +- if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current))) ++ if (likely(rt_mutex_try_acquire(lock))) + return 0; + + return rt_mutex_slowlock(lock, NULL, state); +--- a/kernel/locking/ww_rt_mutex.c ++++ b/kernel/locking/ww_rt_mutex.c +@@ -62,7 +62,7 @@ static int __sched + } + mutex_acquire_nest(&rtm->dep_map, 0, 0, nest_lock, ip); + +- if (likely(rt_mutex_cmpxchg_acquire(&rtm->rtmutex, NULL, current))) { ++ if (likely(rt_mutex_try_acquire(&rtm->rtmutex))) { + if (ww_ctx) + ww_mutex_set_context_fastpath(lock, ww_ctx); + return 0; diff --git a/debian/patches-rt/0002-serial-core-Use-lock-wrappers.patch b/debian/patches-rt/0002-serial-core-Use-lock-wrappers.patch new file mode 100644 index 000000000..ad41a3dc7 --- /dev/null +++ b/debian/patches-rt/0002-serial-core-Use-lock-wrappers.patch @@ -0,0 +1,93 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:19 +0206 +Subject: [PATCH 002/134] serial: core: Use lock wrappers +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Reviewed-by: Ilpo Järvinen +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-3-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/serial_core.h | 12 ++++++------ + 1 file changed, 6 insertions(+), 6 deletions(-) + +--- a/include/linux/serial_core.h ++++ b/include/linux/serial_core.h +@@ -1035,14 +1035,14 @@ static inline void uart_unlock_and_check + u8 sysrq_ch; + + if (!port->has_sysrq) { +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + return; + } + + sysrq_ch = port->sysrq_ch; + port->sysrq_ch = 0; + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + if (sysrq_ch) + handle_sysrq(sysrq_ch); +@@ -1054,14 +1054,14 @@ static inline void uart_unlock_and_check + u8 sysrq_ch; + + if (!port->has_sysrq) { +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + return; + } + + sysrq_ch = port->sysrq_ch; + port->sysrq_ch = 0; + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + if (sysrq_ch) + handle_sysrq(sysrq_ch); +@@ -1077,12 +1077,12 @@ static inline int uart_prepare_sysrq_cha + } + static inline void uart_unlock_and_check_sysrq(struct uart_port *port) + { +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + } + static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port, + unsigned long flags) + { +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + #endif /* CONFIG_MAGIC_SYSRQ_SERIAL */ + diff --git a/debian/patches-rt/0002-signal-Don-t-disable-preemption-in-ptrace_stop-on-PR.patch b/debian/patches-rt/0002-signal-Don-t-disable-preemption-in-ptrace_stop-on-PR.patch new file mode 100644 index 000000000..01e89d97a --- /dev/null +++ b/debian/patches-rt/0002-signal-Don-t-disable-preemption-in-ptrace_stop-on-PR.patch @@ -0,0 +1,48 @@ +From: Sebastian Andrzej Siewior +Date: Thu, 3 Aug 2023 12:09:32 +0200 +Subject: [PATCH 2/2] signal: Don't disable preemption in ptrace_stop() on + PREEMPT_RT. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +On PREEMPT_RT keeping preemption disabled during the invocation of +cgroup_enter_frozen() is a problem because the function acquires css_set_lock +which is a sleeping lock on PREEMPT_RT and must not be acquired with disabled +preemption. +The preempt-disabled section is only for performance optimisation +reasons and can be avoided. + +Extend the comment and don't disable preemption before scheduling on +PREEMPT_RT. + +Acked-by: Oleg Nesterov +Signed-off-by: Sebastian Andrzej Siewior +Link: https://lore.kernel.org/r/20230803100932.325870-3-bigeasy@linutronix.de +--- + kernel/signal.c | 13 +++++++++++-- + 1 file changed, 11 insertions(+), 2 deletions(-) + +--- a/kernel/signal.c ++++ b/kernel/signal.c +@@ -2344,11 +2344,20 @@ static int ptrace_stop(int exit_code, in + * The preempt-disable section ensures that there will be no preemption + * between unlock and schedule() and so improving the performance since + * the ptracer has no reason to sleep. ++ * ++ * On PREEMPT_RT locking tasklist_lock does not disable preemption. ++ * Therefore the task can be preempted (after ++ * do_notify_parent_cldstop()) before unlocking tasklist_lock so there ++ * is no benefit in doing this. The optimisation is harmful on ++ * PEEMPT_RT because the spinlock_t (in cgroup_enter_frozen()) must not ++ * be acquired with disabled preemption. + */ +- preempt_disable(); ++ if (!IS_ENABLED(CONFIG_PREEMPT_RT)) ++ preempt_disable(); + read_unlock(&tasklist_lock); + cgroup_enter_frozen(); +- preempt_enable_no_resched(); ++ if (!IS_ENABLED(CONFIG_PREEMPT_RT)) ++ preempt_enable_no_resched(); + schedule(); + cgroup_leave_frozen(true); + diff --git a/debian/patches-rt/0002-softirq-Add-function-to-preempt-serving-softirqs.patch b/debian/patches-rt/0002-softirq-Add-function-to-preempt-serving-softirqs.patch new file mode 100644 index 000000000..f8cddfa44 --- /dev/null +++ b/debian/patches-rt/0002-softirq-Add-function-to-preempt-serving-softirqs.patch @@ -0,0 +1,60 @@ +From: Sebastian Andrzej Siewior +Date: Fri, 4 Aug 2023 13:30:38 +0200 +Subject: [PATCH 2/3] softirq: Add function to preempt serving softirqs. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Add a functionality for the softirq handler to preempt its current work +if needed. The softirq core has no particular state. It reads and resets +the pending softirq bits and then processes one after the other. +It can already be preempted while it invokes a certain softirq handler. + +By enabling the BH the softirq core releases the per-CPU bh lock which +serializes all softirq handler. It is safe to do as long as the code +does not expect any serialisation in between. A typical scenarion would +after the invocation of callback where no state needs to be preserved +before the next callback is invoked. + +Add functionaliry to preempt the serving softirqs. + +Link: https://lore.kernel.org/r/20230804113039.419794-3-bigeasy@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/bottom_half.h | 2 ++ + kernel/softirq.c | 13 +++++++++++++ + 2 files changed, 15 insertions(+) + +--- a/include/linux/bottom_half.h ++++ b/include/linux/bottom_half.h +@@ -35,8 +35,10 @@ static inline void local_bh_enable(void) + + #ifdef CONFIG_PREEMPT_RT + extern bool local_bh_blocked(void); ++extern void softirq_preempt(void); + #else + static inline bool local_bh_blocked(void) { return false; } ++static inline void softirq_preempt(void) { } + #endif + + #endif /* _LINUX_BH_H */ +--- a/kernel/softirq.c ++++ b/kernel/softirq.c +@@ -247,6 +247,19 @@ void __local_bh_enable_ip(unsigned long + } + EXPORT_SYMBOL(__local_bh_enable_ip); + ++void softirq_preempt(void) ++{ ++ if (WARN_ON_ONCE(!preemptible())) ++ return; ++ ++ if (WARN_ON_ONCE(__this_cpu_read(softirq_ctrl.cnt) != SOFTIRQ_OFFSET)) ++ return; ++ ++ __local_bh_enable(SOFTIRQ_OFFSET, true); ++ /* preemption point */ ++ __local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET); ++} ++ + /* + * Invoked from ksoftirqd_run() outside of the interrupt disabled section + * to acquire the per CPU local lock for reentrancy protection. diff --git a/debian/patches-rt/0003-ARM-vfp-Use-vfp_lock-in-vfp_support_entry.patch b/debian/patches-rt/0003-ARM-vfp-Use-vfp_lock-in-vfp_support_entry.patch new file mode 100644 index 000000000..c02278e5a --- /dev/null +++ b/debian/patches-rt/0003-ARM-vfp-Use-vfp_lock-in-vfp_support_entry.patch @@ -0,0 +1,48 @@ +From: Sebastian Andrzej Siewior +Date: Wed, 28 Jun 2023 09:36:10 +0200 +Subject: [PATCH 3/4] ARM: vfp: Use vfp_lock() in vfp_support_entry(). +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +vfp_entry() is invoked from exception handler and is fully preemptible. +It uses local_bh_disable() to remain uninterrupted while checking the +VFP state. +This is not working on PREEMPT_RT because local_bh_disable() +synchronizes the relevant section but the context remains fully +preemptible. + +Use vfp_lock() for uninterrupted access. + +Signed-off-by: Sebastian Andrzej Siewior +--- + arch/arm/vfp/vfpmodule.c | 6 +++--- + 1 file changed, 3 insertions(+), 3 deletions(-) + +--- a/arch/arm/vfp/vfpmodule.c ++++ b/arch/arm/vfp/vfpmodule.c +@@ -708,7 +708,7 @@ static int vfp_support_entry(struct pt_r + if (!user_mode(regs)) + return vfp_kmode_exception(regs, trigger); + +- local_bh_disable(); ++ vfp_lock(); + fpexc = fmrx(FPEXC); + + /* +@@ -787,7 +787,7 @@ static int vfp_support_entry(struct pt_r + if (!(fpscr & FPSCR_IXE)) { + if (!(fpscr & FPSCR_LENGTH_MASK)) { + pr_debug("not VFP\n"); +- local_bh_enable(); ++ vfp_unlock(); + return -ENOEXEC; + } + fpexc |= FPEXC_DEX; +@@ -797,7 +797,7 @@ bounce: regs->ARM_pc += 4; + VFP_bounce(trigger, fpexc, regs); + } + +- local_bh_enable(); ++ vfp_unlock(); + return 0; + } + diff --git a/debian/patches-rt/0003-drm-amd-display-Add-a-warning-if-the-FPU-is-used-out.patch b/debian/patches-rt/0003-drm-amd-display-Add-a-warning-if-the-FPU-is-used-out.patch new file mode 100644 index 000000000..9e160d5a2 --- /dev/null +++ b/debian/patches-rt/0003-drm-amd-display-Add-a-warning-if-the-FPU-is-used-out.patch @@ -0,0 +1,26 @@ +From: Sebastian Andrzej Siewior +Date: Thu, 21 Sep 2023 16:15:14 +0200 +Subject: [PATCH 3/5] drm/amd/display: Add a warning if the FPU is used outside + from task context. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Add a warning if the FPU is used from any context other than task +context. This is only precaution since the code is not able to be used +from softirq while the API allows it on x86 for instance. + +Link: https://lore.kernel.org/r/20230921141516.520471-4-bigeasy@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c | 1 + + 1 file changed, 1 insertion(+) + +--- a/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c ++++ b/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c +@@ -84,6 +84,7 @@ void dc_fpu_begin(const char *function_n + { + int depth; + ++ WARN_ON_ONCE(!in_task()); + preempt_disable(); + depth = __this_cpu_inc_return(fpu_recursion_depth); + diff --git a/debian/patches-rt/0003-drm-i915-Use-preempt_disable-enable_rt-where-recomme.patch b/debian/patches-rt/0003-drm-i915-Use-preempt_disable-enable_rt-where-recomme.patch new file mode 100644 index 000000000..f2752d090 --- /dev/null +++ b/debian/patches-rt/0003-drm-i915-Use-preempt_disable-enable_rt-where-recomme.patch @@ -0,0 +1,56 @@ +From: Mike Galbraith +Date: Sat, 27 Feb 2016 08:09:11 +0100 +Subject: [PATCH 03/10] drm/i915: Use preempt_disable/enable_rt() where + recommended +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Mario Kleiner suggest in commit + ad3543ede630f ("drm/intel: Push get_scanout_position() timestamping into kms driver.") + +a spots where preemption should be disabled on PREEMPT_RT. The +difference is that on PREEMPT_RT the intel_uncore::lock disables neither +preemption nor interrupts and so region remains preemptible. + +The area covers only register reads and writes. The part that worries me +is: +- __intel_get_crtc_scanline() the worst case is 100us if no match is + found. + +- intel_crtc_scanlines_since_frame_timestamp() not sure how long this + may take in the worst case. + +It was in the RT queue for a while and nobody complained. +Disable preemption on PREEPMPT_RT during timestamping. + +[bigeasy: patch description.] + +Cc: Mario Kleiner +Signed-off-by: Mike Galbraith +Signed-off-by: Thomas Gleixner +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/gpu/drm/i915/display/intel_vblank.c | 6 ++++-- + 1 file changed, 4 insertions(+), 2 deletions(-) + +--- a/drivers/gpu/drm/i915/display/intel_vblank.c ++++ b/drivers/gpu/drm/i915/display/intel_vblank.c +@@ -294,7 +294,8 @@ static bool i915_get_crtc_scanoutpos(str + */ + spin_lock_irqsave(&dev_priv->uncore.lock, irqflags); + +- /* preempt_disable_rt() should go right here in PREEMPT_RT patchset. */ ++ if (IS_ENABLED(CONFIG_PREEMPT_RT)) ++ preempt_disable(); + + /* Get optional system timestamp before query. */ + if (stime) +@@ -358,7 +359,8 @@ static bool i915_get_crtc_scanoutpos(str + if (etime) + *etime = ktime_get(); + +- /* preempt_enable_rt() should go right here in PREEMPT_RT patchset. */ ++ if (IS_ENABLED(CONFIG_PREEMPT_RT)) ++ preempt_enable(); + + spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags); + diff --git a/debian/patches-rt/0003-sched-Extract-__schedule_loop.patch b/debian/patches-rt/0003-sched-Extract-__schedule_loop.patch new file mode 100644 index 000000000..a236df532 --- /dev/null +++ b/debian/patches-rt/0003-sched-Extract-__schedule_loop.patch @@ -0,0 +1,58 @@ +From: Thomas Gleixner +Date: Fri, 8 Sep 2023 18:22:50 +0200 +Subject: [PATCH 3/7] sched: Extract __schedule_loop() +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +There are currently two implementations of this basic __schedule() +loop, and there is soon to be a third. + +Signed-off-by: Thomas Gleixner +Signed-off-by: Sebastian Andrzej Siewior +Signed-off-by: Peter Zijlstra (Intel) +Link: https://lkml.kernel.org/r/20230908162254.999499-4-bigeasy@linutronix.de +--- + kernel/sched/core.c | 21 +++++++++++---------- + 1 file changed, 11 insertions(+), 10 deletions(-) + +--- a/kernel/sched/core.c ++++ b/kernel/sched/core.c +@@ -6771,16 +6771,21 @@ static void sched_update_worker(struct t + } + } + +-asmlinkage __visible void __sched schedule(void) ++static __always_inline void __schedule_loop(unsigned int sched_mode) + { +- struct task_struct *tsk = current; +- +- sched_submit_work(tsk); + do { + preempt_disable(); +- __schedule(SM_NONE); ++ __schedule(sched_mode); + sched_preempt_enable_no_resched(); + } while (need_resched()); ++} ++ ++asmlinkage __visible void __sched schedule(void) ++{ ++ struct task_struct *tsk = current; ++ ++ sched_submit_work(tsk); ++ __schedule_loop(SM_NONE); + sched_update_worker(tsk); + } + EXPORT_SYMBOL(schedule); +@@ -6844,11 +6849,7 @@ void __sched schedule_preempt_disabled(v + #ifdef CONFIG_PREEMPT_RT + void __sched notrace schedule_rtlock(void) + { +- do { +- preempt_disable(); +- __schedule(SM_RTLOCK_WAIT); +- sched_preempt_enable_no_resched(); +- } while (need_resched()); ++ __schedule_loop(SM_RTLOCK_WAIT); + } + NOKPROBE_SYMBOL(schedule_rtlock); + #endif diff --git a/debian/patches-rt/0003-serial-21285-Use-port-lock-wrappers.patch b/debian/patches-rt/0003-serial-21285-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..e025de601 --- /dev/null +++ b/debian/patches-rt/0003-serial-21285-Use-port-lock-wrappers.patch @@ -0,0 +1,75 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:20 +0206 +Subject: [PATCH 003/134] serial: 21285: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-4-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/21285.c | 8 ++++---- + 1 file changed, 4 insertions(+), 4 deletions(-) + +--- a/drivers/tty/serial/21285.c ++++ b/drivers/tty/serial/21285.c +@@ -185,14 +185,14 @@ static void serial21285_break_ctl(struct + unsigned long flags; + unsigned int h_lcr; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + h_lcr = *CSR_H_UBRLCR; + if (break_state) + h_lcr |= H_UBRLCR_BREAK; + else + h_lcr &= ~H_UBRLCR_BREAK; + *CSR_H_UBRLCR = h_lcr; +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int serial21285_startup(struct uart_port *port) +@@ -272,7 +272,7 @@ serial21285_set_termios(struct uart_port + if (port->fifosize) + h_lcr |= H_UBRLCR_FIFO; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* + * Update the per-port timeout. +@@ -309,7 +309,7 @@ serial21285_set_termios(struct uart_port + *CSR_H_UBRLCR = h_lcr; + *CSR_UARTCON = 1; + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *serial21285_type(struct uart_port *port) diff --git a/debian/patches-rt/0003-time-Allow-to-preempt-after-a-callback.patch b/debian/patches-rt/0003-time-Allow-to-preempt-after-a-callback.patch new file mode 100644 index 000000000..7ede7d6ae --- /dev/null +++ b/debian/patches-rt/0003-time-Allow-to-preempt-after-a-callback.patch @@ -0,0 +1,47 @@ +From: Sebastian Andrzej Siewior +Date: Fri, 4 Aug 2023 13:30:39 +0200 +Subject: [PATCH 3/3] time: Allow to preempt after a callback. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +The TIMER_SOFTIRQ handler invokes timer callbacks of the expired timers. +Before each invocation the timer_base::lock is dropped. The only lock +that is still held is the timer_base::expiry_lock and the per-CPU +bh-lock as part of local_bh_disable(). The former is released as part +of lock up prevention if the timer is preempted by the caller which is +waiting for its completion. + +Both locks are already released as part of timer_sync_wait_running(). +This can be extended by also releasing in bh-lock. The timer core does +not rely on any state that is serialized by the bh-lock. The timer +callback expects the bh-state to be serialized by the lock but there is +no need to keep state synchronized while invoking multiple callbacks. + +Preempt handling softirqs and release all locks after a timer invocation +if the current has inherited priority. + +Link: https://lore.kernel.org/r/20230804113039.419794-4-bigeasy@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/time/timer.c | 9 ++++++++- + 1 file changed, 8 insertions(+), 1 deletion(-) + +--- a/kernel/time/timer.c ++++ b/kernel/time/timer.c +@@ -1470,9 +1470,16 @@ static inline void timer_base_unlock_exp + */ + static void timer_sync_wait_running(struct timer_base *base) + { +- if (atomic_read(&base->timer_waiters)) { ++ bool need_preempt; ++ ++ need_preempt = task_is_pi_boosted(current); ++ if (need_preempt || atomic_read(&base->timer_waiters)) { + raw_spin_unlock_irq(&base->lock); + spin_unlock(&base->expiry_lock); ++ ++ if (need_preempt) ++ softirq_preempt(); ++ + spin_lock(&base->expiry_lock); + raw_spin_lock_irq(&base->lock); + } diff --git a/debian/patches-rt/0004-ARM-vfp-Move-sending-signals-outside-of-vfp_lock-ed-.patch b/debian/patches-rt/0004-ARM-vfp-Move-sending-signals-outside-of-vfp_lock-ed-.patch new file mode 100644 index 000000000..f7e006261 --- /dev/null +++ b/debian/patches-rt/0004-ARM-vfp-Move-sending-signals-outside-of-vfp_lock-ed-.patch @@ -0,0 +1,121 @@ +From: Sebastian Andrzej Siewior +Date: Wed, 28 Jun 2023 09:39:33 +0200 +Subject: [PATCH 4/4] ARM: vfp: Move sending signals outside of vfp_lock()ed + section. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +VFP_bounce() is invoked from within vfp_support_entry() and may send a +signal. Sending a signal uses spinlock_t which becomes a sleeping lock +on PREEMPT_RT and must not be acquired within a preempt-disabled +section. + +Move the vfp_raise_sigfpe() block outside of the vfp_lock() section. + +Signed-off-by: Sebastian Andrzej Siewior +--- + arch/arm/vfp/vfpmodule.c | 29 ++++++++++++++++++----------- + 1 file changed, 18 insertions(+), 11 deletions(-) + +--- a/arch/arm/vfp/vfpmodule.c ++++ b/arch/arm/vfp/vfpmodule.c +@@ -268,7 +268,7 @@ static void vfp_panic(char *reason, u32 + /* + * Process bitmask of exception conditions. + */ +-static void vfp_raise_exceptions(u32 exceptions, u32 inst, u32 fpscr, struct pt_regs *regs) ++static int vfp_raise_exceptions(u32 exceptions, u32 inst, u32 fpscr) + { + int si_code = 0; + +@@ -276,8 +276,7 @@ static void vfp_raise_exceptions(u32 exc + + if (exceptions == VFP_EXCEPTION_ERROR) { + vfp_panic("unhandled bounce", inst); +- vfp_raise_sigfpe(FPE_FLTINV, regs); +- return; ++ return FPE_FLTINV; + } + + /* +@@ -305,8 +304,7 @@ static void vfp_raise_exceptions(u32 exc + RAISE(FPSCR_OFC, FPSCR_OFE, FPE_FLTOVF); + RAISE(FPSCR_IOC, FPSCR_IOE, FPE_FLTINV); + +- if (si_code) +- vfp_raise_sigfpe(si_code, regs); ++ return si_code; + } + + /* +@@ -352,6 +350,8 @@ static u32 vfp_emulate_instruction(u32 i + static void VFP_bounce(u32 trigger, u32 fpexc, struct pt_regs *regs) + { + u32 fpscr, orig_fpscr, fpsid, exceptions; ++ int si_code2 = 0; ++ int si_code = 0; + + pr_debug("VFP: bounce: trigger %08x fpexc %08x\n", trigger, fpexc); + +@@ -397,8 +397,8 @@ static void VFP_bounce(u32 trigger, u32 + * unallocated VFP instruction but with FPSCR.IXE set and not + * on VFP subarch 1. + */ +- vfp_raise_exceptions(VFP_EXCEPTION_ERROR, trigger, fpscr, regs); +- return; ++ si_code = vfp_raise_exceptions(VFP_EXCEPTION_ERROR, trigger, fpscr); ++ goto exit; + } + + /* +@@ -422,14 +422,14 @@ static void VFP_bounce(u32 trigger, u32 + */ + exceptions = vfp_emulate_instruction(trigger, fpscr, regs); + if (exceptions) +- vfp_raise_exceptions(exceptions, trigger, orig_fpscr, regs); ++ si_code2 = vfp_raise_exceptions(exceptions, trigger, orig_fpscr); + + /* + * If there isn't a second FP instruction, exit now. Note that + * the FPEXC.FP2V bit is valid only if FPEXC.EX is 1. + */ + if ((fpexc & (FPEXC_EX | FPEXC_FP2V)) != (FPEXC_EX | FPEXC_FP2V)) +- return; ++ goto exit; + + /* + * The barrier() here prevents fpinst2 being read +@@ -441,7 +441,13 @@ static void VFP_bounce(u32 trigger, u32 + emulate: + exceptions = vfp_emulate_instruction(trigger, orig_fpscr, regs); + if (exceptions) +- vfp_raise_exceptions(exceptions, trigger, orig_fpscr, regs); ++ si_code = vfp_raise_exceptions(exceptions, trigger, orig_fpscr); ++exit: ++ vfp_unlock(); ++ if (si_code2) ++ vfp_raise_sigfpe(si_code2, regs); ++ if (si_code) ++ vfp_raise_sigfpe(si_code, regs); + } + + static void vfp_enable(void *unused) +@@ -773,6 +779,7 @@ static int vfp_support_entry(struct pt_r + * replay the instruction that trapped. + */ + fmxr(FPEXC, fpexc); ++ vfp_unlock(); + } else { + /* Check for synchronous or asynchronous exceptions */ + if (!(fpexc & (FPEXC_EX | FPEXC_DEX))) { +@@ -794,10 +801,10 @@ static int vfp_support_entry(struct pt_r + } + } + bounce: regs->ARM_pc += 4; ++ /* VFP_bounce() will invoke vfp_unlock() */ + VFP_bounce(trigger, fpexc, regs); + } + +- vfp_unlock(); + return 0; + } + diff --git a/debian/patches-rt/0004-drm-amd-display-Move-the-memory-allocation-out-of-dc.patch b/debian/patches-rt/0004-drm-amd-display-Move-the-memory-allocation-out-of-dc.patch new file mode 100644 index 000000000..a1c046b36 --- /dev/null +++ b/debian/patches-rt/0004-drm-amd-display-Move-the-memory-allocation-out-of-dc.patch @@ -0,0 +1,87 @@ +From: Sebastian Andrzej Siewior +Date: Thu, 21 Sep 2023 16:15:15 +0200 +Subject: [PATCH 4/5] drm/amd/display: Move the memory allocation out of + dcn21_validate_bandwidth_fp(). +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +dcn21_validate_bandwidth_fp() is invoked while FPU access has been +enabled. FPU access requires disabling preemption even on PREEMPT_RT. +It is not possible to allocate memory with disabled preemption even with +GFP_ATOMIC on PREEMPT_RT. + +Move the memory allocation before FPU access is enabled. + +Link: https://bugzilla.kernel.org/show_bug.cgi?id=217928 +Link: https://lore.kernel.org/r/20230921141516.520471-5-bigeasy@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/gpu/drm/amd/display/dc/dcn21/dcn21_resource.c | 10 +++++++++- + drivers/gpu/drm/amd/display/dc/dml/dcn20/dcn20_fpu.c | 7 ++----- + drivers/gpu/drm/amd/display/dc/dml/dcn20/dcn20_fpu.h | 5 ++--- + 3 files changed, 13 insertions(+), 9 deletions(-) + +--- a/drivers/gpu/drm/amd/display/dc/dcn21/dcn21_resource.c ++++ b/drivers/gpu/drm/amd/display/dc/dcn21/dcn21_resource.c +@@ -953,9 +953,17 @@ static bool dcn21_validate_bandwidth(str + bool fast_validate) + { + bool voltage_supported; ++ display_e2e_pipe_params_st *pipes; ++ ++ pipes = kcalloc(dc->res_pool->pipe_count, sizeof(display_e2e_pipe_params_st), GFP_KERNEL); ++ if (!pipes) ++ return false; ++ + DC_FP_START(); +- voltage_supported = dcn21_validate_bandwidth_fp(dc, context, fast_validate); ++ voltage_supported = dcn21_validate_bandwidth_fp(dc, context, fast_validate, pipes); + DC_FP_END(); ++ ++ kfree(pipes); + return voltage_supported; + } + +--- a/drivers/gpu/drm/amd/display/dc/dml/dcn20/dcn20_fpu.c ++++ b/drivers/gpu/drm/amd/display/dc/dml/dcn20/dcn20_fpu.c +@@ -2203,9 +2203,8 @@ static void dcn21_calculate_wm(struct dc + &context->bw_ctx.dml, pipes, pipe_cnt); + } + +-bool dcn21_validate_bandwidth_fp(struct dc *dc, +- struct dc_state *context, +- bool fast_validate) ++bool dcn21_validate_bandwidth_fp(struct dc *dc, struct dc_state *context, ++ bool fast_validate, display_e2e_pipe_params_st *pipes) + { + bool out = false; + +@@ -2214,7 +2213,6 @@ bool dcn21_validate_bandwidth_fp(struct + int vlevel = 0; + int pipe_split_from[MAX_PIPES]; + int pipe_cnt = 0; +- display_e2e_pipe_params_st *pipes = kzalloc(dc->res_pool->pipe_count * sizeof(display_e2e_pipe_params_st), GFP_ATOMIC); + DC_LOGGER_INIT(dc->ctx->logger); + + BW_VAL_TRACE_COUNT(); +@@ -2254,7 +2252,6 @@ bool dcn21_validate_bandwidth_fp(struct + out = false; + + validate_out: +- kfree(pipes); + + BW_VAL_TRACE_FINISH(); + +--- a/drivers/gpu/drm/amd/display/dc/dml/dcn20/dcn20_fpu.h ++++ b/drivers/gpu/drm/amd/display/dc/dml/dcn20/dcn20_fpu.h +@@ -77,9 +77,8 @@ int dcn21_populate_dml_pipes_from_contex + struct dc_state *context, + display_e2e_pipe_params_st *pipes, + bool fast_validate); +-bool dcn21_validate_bandwidth_fp(struct dc *dc, +- struct dc_state *context, +- bool fast_validate); ++bool dcn21_validate_bandwidth_fp(struct dc *dc, struct dc_state *context, bool ++ fast_validate, display_e2e_pipe_params_st *pipes); + void dcn21_update_bw_bounding_box(struct dc *dc, struct clk_bw_params *bw_params); + + void dcn21_clk_mgr_set_bw_params_wm_table(struct clk_bw_params *bw_params); diff --git a/debian/patches-rt/0004-drm-i915-Don-t-disable-interrupts-on-PREEMPT_RT-duri.patch b/debian/patches-rt/0004-drm-i915-Don-t-disable-interrupts-on-PREEMPT_RT-duri.patch new file mode 100644 index 000000000..9c386e518 --- /dev/null +++ b/debian/patches-rt/0004-drm-i915-Don-t-disable-interrupts-on-PREEMPT_RT-duri.patch @@ -0,0 +1,85 @@ +From: Mike Galbraith +Date: Sat, 27 Feb 2016 09:01:42 +0100 +Subject: [PATCH 04/10] drm/i915: Don't disable interrupts on PREEMPT_RT during + atomic updates +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Commit + 8d7849db3eab7 ("drm/i915: Make sprite updates atomic") + +started disabling interrupts across atomic updates. This breaks on PREEMPT_RT +because within this section the code attempt to acquire spinlock_t locks which +are sleeping locks on PREEMPT_RT. + +According to the comment the interrupts are disabled to avoid random delays and +not required for protection or synchronisation. +If this needs to happen with disabled interrupts on PREEMPT_RT, and the +whole section is restricted to register access then all sleeping locks +need to be acquired before interrupts are disabled and some function +maybe moved after enabling interrupts again. +This includes: +- prepare_to_wait() + finish_wait() due its wake queue. +- drm_crtc_vblank_put() -> vblank_disable_fn() drm_device::vbl_lock. +- skl_pfit_enable(), intel_update_plane(), vlv_atomic_update_fifo() and + maybe others due to intel_uncore::lock +- drm_crtc_arm_vblank_event() due to drm_device::event_lock and + drm_device::vblank_time_lock. + +Don't disable interrupts on PREEMPT_RT during atomic updates. + +[bigeasy: drop local locks, commit message] + +Signed-off-by: Mike Galbraith +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/gpu/drm/i915/display/intel_crtc.c | 15 ++++++++++----- + 1 file changed, 10 insertions(+), 5 deletions(-) + +--- a/drivers/gpu/drm/i915/display/intel_crtc.c ++++ b/drivers/gpu/drm/i915/display/intel_crtc.c +@@ -534,7 +534,8 @@ void intel_pipe_update_start(struct inte + */ + intel_psr_wait_for_idle_locked(new_crtc_state); + +- local_irq_disable(); ++ if (!IS_ENABLED(CONFIG_PREEMPT_RT)) ++ local_irq_disable(); + + crtc->debug.min_vbl = min; + crtc->debug.max_vbl = max; +@@ -559,11 +560,13 @@ void intel_pipe_update_start(struct inte + break; + } + +- local_irq_enable(); ++ if (!IS_ENABLED(CONFIG_PREEMPT_RT)) ++ local_irq_enable(); + + timeout = schedule_timeout(timeout); + +- local_irq_disable(); ++ if (!IS_ENABLED(CONFIG_PREEMPT_RT)) ++ local_irq_disable(); + } + + finish_wait(wq, &wait); +@@ -596,7 +599,8 @@ void intel_pipe_update_start(struct inte + return; + + irq_disable: +- local_irq_disable(); ++ if (!IS_ENABLED(CONFIG_PREEMPT_RT)) ++ local_irq_disable(); + } + + #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_VBLANK_EVADE) +@@ -706,7 +710,8 @@ void intel_pipe_update_end(struct intel_ + intel_crtc_update_active_timings(new_crtc_state, + new_crtc_state->vrr.enable); + +- local_irq_enable(); ++ if (!IS_ENABLED(CONFIG_PREEMPT_RT)) ++ local_irq_enable(); + + if (intel_vgpu_active(dev_priv)) + return; diff --git a/debian/patches-rt/0004-sched-Provide-rt_mutex-specific-scheduler-helpers.patch b/debian/patches-rt/0004-sched-Provide-rt_mutex-specific-scheduler-helpers.patch new file mode 100644 index 000000000..f61a67ea3 --- /dev/null +++ b/debian/patches-rt/0004-sched-Provide-rt_mutex-specific-scheduler-helpers.patch @@ -0,0 +1,128 @@ +From: Peter Zijlstra +Date: Fri, 8 Sep 2023 18:22:51 +0200 +Subject: [PATCH 4/7] sched: Provide rt_mutex specific scheduler helpers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +With PREEMPT_RT there is a rt_mutex recursion problem where +sched_submit_work() can use an rtlock (aka spinlock_t). More +specifically what happens is: + + mutex_lock() /* really rt_mutex */ + ... + __rt_mutex_slowlock_locked() + task_blocks_on_rt_mutex() + // enqueue current task as waiter + // do PI chain walk + rt_mutex_slowlock_block() + schedule() + sched_submit_work() + ... + spin_lock() /* really rtlock */ + ... + __rt_mutex_slowlock_locked() + task_blocks_on_rt_mutex() + // enqueue current task as waiter *AGAIN* + // *CONFUSION* + +Fix this by making rt_mutex do the sched_submit_work() early, before +it enqueues itself as a waiter -- before it even knows *if* it will +wait. + +[[ basically Thomas' patch but with different naming and a few asserts + added ]] + +Originally-by: Thomas Gleixner +Signed-off-by: Peter Zijlstra (Intel) +Signed-off-by: Sebastian Andrzej Siewior +Signed-off-by: Peter Zijlstra (Intel) +Link: https://lkml.kernel.org/r/20230908162254.999499-5-bigeasy@linutronix.de +--- + include/linux/sched.h | 3 +++ + include/linux/sched/rt.h | 4 ++++ + kernel/sched/core.c | 36 ++++++++++++++++++++++++++++++++---- + 3 files changed, 39 insertions(+), 4 deletions(-) + +--- a/include/linux/sched.h ++++ b/include/linux/sched.h +@@ -911,6 +911,9 @@ struct task_struct { + * ->sched_remote_wakeup gets used, so it can be in this word. + */ + unsigned sched_remote_wakeup:1; ++#ifdef CONFIG_RT_MUTEXES ++ unsigned sched_rt_mutex:1; ++#endif + + /* Bit to tell LSMs we're in execve(): */ + unsigned in_execve:1; +--- a/include/linux/sched/rt.h ++++ b/include/linux/sched/rt.h +@@ -30,6 +30,10 @@ static inline bool task_is_realtime(stru + } + + #ifdef CONFIG_RT_MUTEXES ++extern void rt_mutex_pre_schedule(void); ++extern void rt_mutex_schedule(void); ++extern void rt_mutex_post_schedule(void); ++ + /* + * Must hold either p->pi_lock or task_rq(p)->lock. + */ +--- a/kernel/sched/core.c ++++ b/kernel/sched/core.c +@@ -6724,9 +6724,6 @@ static inline void sched_submit_work(str + static DEFINE_WAIT_OVERRIDE_MAP(sched_map, LD_WAIT_CONFIG); + unsigned int task_flags; + +- if (task_is_running(tsk)) +- return; +- + /* + * Establish LD_WAIT_CONFIG context to ensure none of the code called + * will use a blocking primitive -- which would lead to recursion. +@@ -6784,7 +6781,12 @@ asmlinkage __visible void __sched schedu + { + struct task_struct *tsk = current; + +- sched_submit_work(tsk); ++#ifdef CONFIG_RT_MUTEXES ++ lockdep_assert(!tsk->sched_rt_mutex); ++#endif ++ ++ if (!task_is_running(tsk)) ++ sched_submit_work(tsk); + __schedule_loop(SM_NONE); + sched_update_worker(tsk); + } +@@ -7045,6 +7047,32 @@ static void __setscheduler_prio(struct t + + #ifdef CONFIG_RT_MUTEXES + ++/* ++ * Would be more useful with typeof()/auto_type but they don't mix with ++ * bit-fields. Since it's a local thing, use int. Keep the generic sounding ++ * name such that if someone were to implement this function we get to compare ++ * notes. ++ */ ++#define fetch_and_set(x, v) ({ int _x = (x); (x) = (v); _x; }) ++ ++void rt_mutex_pre_schedule(void) ++{ ++ lockdep_assert(!fetch_and_set(current->sched_rt_mutex, 1)); ++ sched_submit_work(current); ++} ++ ++void rt_mutex_schedule(void) ++{ ++ lockdep_assert(current->sched_rt_mutex); ++ __schedule_loop(SM_NONE); ++} ++ ++void rt_mutex_post_schedule(void) ++{ ++ sched_update_worker(current); ++ lockdep_assert(fetch_and_set(current->sched_rt_mutex, 0)); ++} ++ + static inline int __rt_effective_prio(struct task_struct *pi_task, int prio) + { + if (pi_task) diff --git a/debian/patches-rt/0004-serial-8250_aspeed_vuart-Use-port-lock-wrappers.patch b/debian/patches-rt/0004-serial-8250_aspeed_vuart-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..eb65ac58f --- /dev/null +++ b/debian/patches-rt/0004-serial-8250_aspeed_vuart-Use-port-lock-wrappers.patch @@ -0,0 +1,61 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:21 +0206 +Subject: [PATCH 004/134] serial: 8250_aspeed_vuart: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-5-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/8250/8250_aspeed_vuart.c | 6 +++--- + 1 file changed, 3 insertions(+), 3 deletions(-) + +--- a/drivers/tty/serial/8250/8250_aspeed_vuart.c ++++ b/drivers/tty/serial/8250/8250_aspeed_vuart.c +@@ -288,9 +288,9 @@ static void aspeed_vuart_set_throttle(st + struct uart_8250_port *up = up_to_u8250p(port); + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + __aspeed_vuart_set_throttle(up, throttle); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void aspeed_vuart_throttle(struct uart_port *port) +@@ -340,7 +340,7 @@ static int aspeed_vuart_handle_irq(struc + if (iir & UART_IIR_NO_INT) + return 0; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + lsr = serial_port_in(port, UART_LSR); + diff --git a/debian/patches-rt/0005-drm-amd-display-Move-the-memory-allocation-out-of-dc.patch b/debian/patches-rt/0005-drm-amd-display-Move-the-memory-allocation-out-of-dc.patch new file mode 100644 index 000000000..1a2babc61 --- /dev/null +++ b/debian/patches-rt/0005-drm-amd-display-Move-the-memory-allocation-out-of-dc.patch @@ -0,0 +1,121 @@ +From: Sebastian Andrzej Siewior +Date: Thu, 21 Sep 2023 16:15:16 +0200 +Subject: [PATCH 5/5] drm/amd/display: Move the memory allocation out of + dcn20_validate_bandwidth_fp(). +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +dcn20_validate_bandwidth_fp() is invoked while FPU access has been +enabled. FPU access requires disabling preemption even on PREEMPT_RT. +It is not possible to allocate memory with disabled preemption even with +GFP_ATOMIC on PREEMPT_RT. + +Move the memory allocation before FPU access is enabled. +To preserve previous "clean" state of "pipes" add a memset() before the +second invocation of dcn20_validate_bandwidth_internal() where the +variable is used. + +Link: https://lore.kernel.org/r/20230921141516.520471-6-bigeasy@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c | 10 +++++++++- + drivers/gpu/drm/amd/display/dc/dml/dcn20/dcn20_fpu.c | 16 +++++++--------- + drivers/gpu/drm/amd/display/dc/dml/dcn20/dcn20_fpu.h | 5 ++--- + 3 files changed, 18 insertions(+), 13 deletions(-) + +--- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c ++++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c +@@ -2141,9 +2141,17 @@ bool dcn20_validate_bandwidth(struct dc + bool fast_validate) + { + bool voltage_supported; ++ display_e2e_pipe_params_st *pipes; ++ ++ pipes = kcalloc(dc->res_pool->pipe_count, sizeof(display_e2e_pipe_params_st), GFP_KERNEL); ++ if (!pipes) ++ return false; ++ + DC_FP_START(); +- voltage_supported = dcn20_validate_bandwidth_fp(dc, context, fast_validate); ++ voltage_supported = dcn20_validate_bandwidth_fp(dc, context, fast_validate, pipes); + DC_FP_END(); ++ ++ kfree(pipes); + return voltage_supported; + } + +--- a/drivers/gpu/drm/amd/display/dc/dml/dcn20/dcn20_fpu.c ++++ b/drivers/gpu/drm/amd/display/dc/dml/dcn20/dcn20_fpu.c +@@ -1910,7 +1910,7 @@ void dcn20_patch_bounding_box(struct dc + } + + static bool dcn20_validate_bandwidth_internal(struct dc *dc, struct dc_state *context, +- bool fast_validate) ++ bool fast_validate, display_e2e_pipe_params_st *pipes) + { + bool out = false; + +@@ -1919,7 +1919,6 @@ static bool dcn20_validate_bandwidth_int + int vlevel = 0; + int pipe_split_from[MAX_PIPES]; + int pipe_cnt = 0; +- display_e2e_pipe_params_st *pipes = kzalloc(dc->res_pool->pipe_count * sizeof(display_e2e_pipe_params_st), GFP_ATOMIC); + DC_LOGGER_INIT(dc->ctx->logger); + + BW_VAL_TRACE_COUNT(); +@@ -1954,16 +1953,14 @@ static bool dcn20_validate_bandwidth_int + out = false; + + validate_out: +- kfree(pipes); + + BW_VAL_TRACE_FINISH(); + + return out; + } + +-bool dcn20_validate_bandwidth_fp(struct dc *dc, +- struct dc_state *context, +- bool fast_validate) ++bool dcn20_validate_bandwidth_fp(struct dc *dc, struct dc_state *context, ++ bool fast_validate, display_e2e_pipe_params_st *pipes) + { + bool voltage_supported = false; + bool full_pstate_supported = false; +@@ -1982,11 +1979,11 @@ bool dcn20_validate_bandwidth_fp(struct + ASSERT(context != dc->current_state); + + if (fast_validate) { +- return dcn20_validate_bandwidth_internal(dc, context, true); ++ return dcn20_validate_bandwidth_internal(dc, context, true, pipes); + } + + // Best case, we support full UCLK switch latency +- voltage_supported = dcn20_validate_bandwidth_internal(dc, context, false); ++ voltage_supported = dcn20_validate_bandwidth_internal(dc, context, false, pipes); + full_pstate_supported = context->bw_ctx.bw.dcn.clk.p_state_change_support; + + if (context->bw_ctx.dml.soc.dummy_pstate_latency_us == 0 || +@@ -1998,7 +1995,8 @@ bool dcn20_validate_bandwidth_fp(struct + // Fallback: Try to only support G6 temperature read latency + context->bw_ctx.dml.soc.dram_clock_change_latency_us = context->bw_ctx.dml.soc.dummy_pstate_latency_us; + +- voltage_supported = dcn20_validate_bandwidth_internal(dc, context, false); ++ memset(pipes, 0, dc->res_pool->pipe_count * sizeof(display_e2e_pipe_params_st)); ++ voltage_supported = dcn20_validate_bandwidth_internal(dc, context, false, pipes); + dummy_pstate_supported = context->bw_ctx.bw.dcn.clk.p_state_change_support; + + if (voltage_supported && (dummy_pstate_supported || !(context->stream_count))) { +--- a/drivers/gpu/drm/amd/display/dc/dml/dcn20/dcn20_fpu.h ++++ b/drivers/gpu/drm/amd/display/dc/dml/dcn20/dcn20_fpu.h +@@ -61,9 +61,8 @@ void dcn20_update_bounding_box(struct dc + unsigned int num_states); + void dcn20_patch_bounding_box(struct dc *dc, + struct _vcs_dpi_soc_bounding_box_st *bb); +-bool dcn20_validate_bandwidth_fp(struct dc *dc, +- struct dc_state *context, +- bool fast_validate); ++bool dcn20_validate_bandwidth_fp(struct dc *dc, struct dc_state *context, ++ bool fast_validate, display_e2e_pipe_params_st *pipes); + void dcn20_fpu_set_wm_ranges(int i, + struct pp_smu_wm_range_sets *ranges, + struct _vcs_dpi_soc_bounding_box_st *loaded_bb); diff --git a/debian/patches-rt/0005-drm-i915-Don-t-check-for-atomic-context-on-PREEMPT_R.patch b/debian/patches-rt/0005-drm-i915-Don-t-check-for-atomic-context-on-PREEMPT_R.patch new file mode 100644 index 000000000..4af932567 --- /dev/null +++ b/debian/patches-rt/0005-drm-i915-Don-t-check-for-atomic-context-on-PREEMPT_R.patch @@ -0,0 +1,30 @@ +From: Sebastian Andrzej Siewior +Date: Mon, 25 Oct 2021 15:05:18 +0200 +Subject: [PATCH 05/10] drm/i915: Don't check for atomic context on PREEMPT_RT +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +The !in_atomic() check in _wait_for_atomic() triggers on PREEMPT_RT +because the uncore::lock is a spinlock_t and does not disable +preemption or interrupts. + +Changing the uncore:lock to a raw_spinlock_t doubles the worst case +latency on an otherwise idle testbox during testing. Therefore I'm +currently unsure about changing this. + +Link: https://lore.kernel.org/all/20211006164628.s2mtsdd2jdbfyf7g@linutronix.de/ +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/gpu/drm/i915/i915_utils.h | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +--- a/drivers/gpu/drm/i915/i915_utils.h ++++ b/drivers/gpu/drm/i915/i915_utils.h +@@ -288,7 +288,7 @@ wait_remaining_ms_from_jiffies(unsigned + #define wait_for(COND, MS) _wait_for((COND), (MS) * 1000, 10, 1000) + + /* If CONFIG_PREEMPT_COUNT is disabled, in_atomic() always reports false. */ +-#if defined(CONFIG_DRM_I915_DEBUG) && defined(CONFIG_PREEMPT_COUNT) ++#if defined(CONFIG_DRM_I915_DEBUG) && defined(CONFIG_PREEMPT_COUNT) && !defined(CONFIG_PREEMPT_RT) + # define _WAIT_FOR_ATOMIC_CHECK(ATOMIC) WARN_ON_ONCE((ATOMIC) && !in_atomic()) + #else + # define _WAIT_FOR_ATOMIC_CHECK(ATOMIC) do { } while (0) diff --git a/debian/patches-rt/0005-locking-rtmutex-Use-rt_mutex-specific-scheduler-help.patch b/debian/patches-rt/0005-locking-rtmutex-Use-rt_mutex-specific-scheduler-help.patch new file mode 100644 index 000000000..d84497e5f --- /dev/null +++ b/debian/patches-rt/0005-locking-rtmutex-Use-rt_mutex-specific-scheduler-help.patch @@ -0,0 +1,177 @@ +From: Sebastian Andrzej Siewior +Date: Fri, 8 Sep 2023 18:22:52 +0200 +Subject: [PATCH 5/7] locking/rtmutex: Use rt_mutex specific scheduler helpers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Have rt_mutex use the rt_mutex specific scheduler helpers to avoid +recursion vs rtlock on the PI state. + +[[ peterz: adapted to new names ]] + +Reported-by: Crystal Wood +Signed-off-by: Sebastian Andrzej Siewior +Signed-off-by: Peter Zijlstra (Intel) +Link: https://lkml.kernel.org/r/20230908162254.999499-6-bigeasy@linutronix.de +--- + kernel/futex/pi.c | 11 +++++++++++ + kernel/locking/rtmutex.c | 14 ++++++++++++-- + kernel/locking/rwbase_rt.c | 6 ++++++ + kernel/locking/rwsem.c | 8 +++++++- + kernel/locking/spinlock_rt.c | 4 ++++ + 5 files changed, 40 insertions(+), 3 deletions(-) + +--- a/kernel/futex/pi.c ++++ b/kernel/futex/pi.c +@@ -1,6 +1,7 @@ + // SPDX-License-Identifier: GPL-2.0-or-later + + #include ++#include + #include + + #include "futex.h" +@@ -1002,6 +1003,12 @@ int futex_lock_pi(u32 __user *uaddr, uns + goto no_block; + } + ++ /* ++ * Must be done before we enqueue the waiter, here is unfortunately ++ * under the hb lock, but that *should* work because it does nothing. ++ */ ++ rt_mutex_pre_schedule(); ++ + rt_mutex_init_waiter(&rt_waiter); + + /* +@@ -1052,6 +1059,10 @@ int futex_lock_pi(u32 __user *uaddr, uns + if (ret && !rt_mutex_cleanup_proxy_lock(&q.pi_state->pi_mutex, &rt_waiter)) + ret = 0; + ++ /* ++ * Waiter is unqueued. ++ */ ++ rt_mutex_post_schedule(); + no_block: + /* + * Fixup the pi_state owner and possibly acquire the lock if we +--- a/kernel/locking/rtmutex.c ++++ b/kernel/locking/rtmutex.c +@@ -1632,7 +1632,7 @@ static int __sched rt_mutex_slowlock_blo + raw_spin_unlock_irq(&lock->wait_lock); + + if (!owner || !rtmutex_spin_on_owner(lock, waiter, owner)) +- schedule(); ++ rt_mutex_schedule(); + + raw_spin_lock_irq(&lock->wait_lock); + set_current_state(state); +@@ -1661,7 +1661,7 @@ static void __sched rt_mutex_handle_dead + WARN(1, "rtmutex deadlock detected\n"); + while (1) { + set_current_state(TASK_INTERRUPTIBLE); +- schedule(); ++ rt_mutex_schedule(); + } + } + +@@ -1757,6 +1757,15 @@ static int __sched rt_mutex_slowlock(str + int ret; + + /* ++ * Do all pre-schedule work here, before we queue a waiter and invoke ++ * PI -- any such work that trips on rtlock (PREEMPT_RT spinlock) would ++ * otherwise recurse back into task_blocks_on_rt_mutex() through ++ * rtlock_slowlock() and will then enqueue a second waiter for this ++ * same task and things get really confusing real fast. ++ */ ++ rt_mutex_pre_schedule(); ++ ++ /* + * Technically we could use raw_spin_[un]lock_irq() here, but this can + * be called in early boot if the cmpxchg() fast path is disabled + * (debug, no architecture support). In this case we will acquire the +@@ -1767,6 +1776,7 @@ static int __sched rt_mutex_slowlock(str + raw_spin_lock_irqsave(&lock->wait_lock, flags); + ret = __rt_mutex_slowlock_locked(lock, ww_ctx, state); + raw_spin_unlock_irqrestore(&lock->wait_lock, flags); ++ rt_mutex_post_schedule(); + + return ret; + } +--- a/kernel/locking/rwbase_rt.c ++++ b/kernel/locking/rwbase_rt.c +@@ -71,6 +71,7 @@ static int __sched __rwbase_read_lock(st + struct rt_mutex_base *rtm = &rwb->rtmutex; + int ret; + ++ rwbase_pre_schedule(); + raw_spin_lock_irq(&rtm->wait_lock); + + /* +@@ -125,6 +126,7 @@ static int __sched __rwbase_read_lock(st + rwbase_rtmutex_unlock(rtm); + + trace_contention_end(rwb, ret); ++ rwbase_post_schedule(); + return ret; + } + +@@ -237,6 +239,8 @@ static int __sched rwbase_write_lock(str + /* Force readers into slow path */ + atomic_sub(READER_BIAS, &rwb->readers); + ++ rwbase_pre_schedule(); ++ + raw_spin_lock_irqsave(&rtm->wait_lock, flags); + if (__rwbase_write_trylock(rwb)) + goto out_unlock; +@@ -248,6 +252,7 @@ static int __sched rwbase_write_lock(str + if (rwbase_signal_pending_state(state, current)) { + rwbase_restore_current_state(); + __rwbase_write_unlock(rwb, 0, flags); ++ rwbase_post_schedule(); + trace_contention_end(rwb, -EINTR); + return -EINTR; + } +@@ -266,6 +271,7 @@ static int __sched rwbase_write_lock(str + + out_unlock: + raw_spin_unlock_irqrestore(&rtm->wait_lock, flags); ++ rwbase_post_schedule(); + return 0; + } + +--- a/kernel/locking/rwsem.c ++++ b/kernel/locking/rwsem.c +@@ -1427,8 +1427,14 @@ static inline void __downgrade_write(str + #define rwbase_signal_pending_state(state, current) \ + signal_pending_state(state, current) + ++#define rwbase_pre_schedule() \ ++ rt_mutex_pre_schedule() ++ + #define rwbase_schedule() \ +- schedule() ++ rt_mutex_schedule() ++ ++#define rwbase_post_schedule() \ ++ rt_mutex_post_schedule() + + #include "rwbase_rt.c" + +--- a/kernel/locking/spinlock_rt.c ++++ b/kernel/locking/spinlock_rt.c +@@ -184,9 +184,13 @@ static __always_inline int rwbase_rtmut + + #define rwbase_signal_pending_state(state, current) (0) + ++#define rwbase_pre_schedule() ++ + #define rwbase_schedule() \ + schedule_rtlock() + ++#define rwbase_post_schedule() ++ + #include "rwbase_rt.c" + /* + * The common functions which get wrapped into the rwlock API. diff --git a/debian/patches-rt/0005-serial-8250_bcm7271-Use-port-lock-wrappers.patch b/debian/patches-rt/0005-serial-8250_bcm7271-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..55ae035b8 --- /dev/null +++ b/debian/patches-rt/0005-serial-8250_bcm7271-Use-port-lock-wrappers.patch @@ -0,0 +1,151 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:22 +0206 +Subject: [PATCH 005/134] serial: 8250_bcm7271: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-6-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/8250/8250_bcm7271.c | 28 ++++++++++++++-------------- + 1 file changed, 14 insertions(+), 14 deletions(-) + +--- a/drivers/tty/serial/8250/8250_bcm7271.c ++++ b/drivers/tty/serial/8250/8250_bcm7271.c +@@ -567,7 +567,7 @@ static irqreturn_t brcmuart_isr(int irq, + if (interrupts == 0) + return IRQ_NONE; + +- spin_lock_irqsave(&up->lock, flags); ++ uart_port_lock_irqsave(up, &flags); + + /* Clear all interrupts */ + udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_CLEAR, interrupts); +@@ -581,7 +581,7 @@ static irqreturn_t brcmuart_isr(int irq, + if ((rval | tval) == 0) + dev_warn(dev, "Spurious interrupt: 0x%x\n", interrupts); + +- spin_unlock_irqrestore(&up->lock, flags); ++ uart_port_unlock_irqrestore(up, flags); + return IRQ_HANDLED; + } + +@@ -608,10 +608,10 @@ static int brcmuart_startup(struct uart_ + * + * Synchronize UART_IER access against the console. + */ +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + up->ier &= ~UART_IER_RDI; + serial_port_out(port, UART_IER, up->ier); +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + + priv->tx_running = false; + priv->dma.rx_dma = NULL; +@@ -629,7 +629,7 @@ static void brcmuart_shutdown(struct uar + struct brcmuart_priv *priv = up->port.private_data; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + priv->shutdown = true; + if (priv->dma_enabled) { + stop_rx_dma(up); +@@ -645,7 +645,7 @@ static void brcmuart_shutdown(struct uar + */ + up->dma = NULL; + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + serial8250_do_shutdown(port); + } + +@@ -788,7 +788,7 @@ static int brcmuart_handle_irq(struct ua + * interrupt but there is no data ready. + */ + if (((iir & UART_IIR_ID) == UART_IIR_RX_TIMEOUT) && !(priv->shutdown)) { +- spin_lock_irqsave(&p->lock, flags); ++ uart_port_lock_irqsave(p, &flags); + status = serial_port_in(p, UART_LSR); + if ((status & UART_LSR_DR) == 0) { + +@@ -813,7 +813,7 @@ static int brcmuart_handle_irq(struct ua + + handled = 1; + } +- spin_unlock_irqrestore(&p->lock, flags); ++ uart_port_unlock_irqrestore(p, flags); + if (handled) + return 1; + } +@@ -831,7 +831,7 @@ static enum hrtimer_restart brcmuart_hrt + if (priv->shutdown) + return HRTIMER_NORESTART; + +- spin_lock_irqsave(&p->lock, flags); ++ uart_port_lock_irqsave(p, &flags); + status = serial_port_in(p, UART_LSR); + + /* +@@ -855,7 +855,7 @@ static enum hrtimer_restart brcmuart_hrt + status |= UART_MCR_RTS; + serial_port_out(p, UART_MCR, status); + } +- spin_unlock_irqrestore(&p->lock, flags); ++ uart_port_unlock_irqrestore(p, flags); + return HRTIMER_NORESTART; + } + +@@ -1154,10 +1154,10 @@ static int __maybe_unused brcmuart_suspe + * This will prevent resume from enabling RTS before the + * baud rate has been restored. + */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + priv->saved_mctrl = port->mctrl; + port->mctrl &= ~TIOCM_RTS; +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + serial8250_suspend_port(priv->line); + clk_disable_unprepare(priv->baud_mux_clk); +@@ -1196,10 +1196,10 @@ static int __maybe_unused brcmuart_resum + + if (priv->saved_mctrl & TIOCM_RTS) { + /* Restore RTS */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + port->mctrl |= TIOCM_RTS; + port->ops->set_mctrl(port, port->mctrl); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + return 0; diff --git a/debian/patches-rt/0006-drm-i915-Disable-tracing-points-on-PREEMPT_RT.patch b/debian/patches-rt/0006-drm-i915-Disable-tracing-points-on-PREEMPT_RT.patch new file mode 100644 index 000000000..f29f29bdf --- /dev/null +++ b/debian/patches-rt/0006-drm-i915-Disable-tracing-points-on-PREEMPT_RT.patch @@ -0,0 +1,45 @@ +From: Sebastian Andrzej Siewior +Date: Thu, 6 Dec 2018 09:52:20 +0100 +Subject: [PATCH 06/10] drm/i915: Disable tracing points on PREEMPT_RT +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Luca Abeni reported this: +| BUG: scheduling while atomic: kworker/u8:2/15203/0x00000003 +| CPU: 1 PID: 15203 Comm: kworker/u8:2 Not tainted 4.19.1-rt3 #10 +| Call Trace: +| rt_spin_lock+0x3f/0x50 +| gen6_read32+0x45/0x1d0 [i915] +| g4x_get_vblank_counter+0x36/0x40 [i915] +| trace_event_raw_event_i915_pipe_update_start+0x7d/0xf0 [i915] + +The tracing events use trace_i915_pipe_update_start() among other events +use functions acquire spinlock_t locks which are transformed into +sleeping locks on PREEMPT_RT. A few trace points use +intel_get_crtc_scanline(), others use ->get_vblank_counter() wich also +might acquire a sleeping locks on PREEMPT_RT. +At the time the arguments are evaluated within trace point, preemption +is disabled and so the locks must not be acquired on PREEMPT_RT. + +Based on this I don't see any other way than disable trace points on +PREMPT_RT. + +Reported-by: Luca Abeni +Cc: Steven Rostedt +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/gpu/drm/i915/i915_trace.h | 4 ++++ + 1 file changed, 4 insertions(+) + +--- a/drivers/gpu/drm/i915/i915_trace.h ++++ b/drivers/gpu/drm/i915/i915_trace.h +@@ -6,6 +6,10 @@ + #if !defined(_I915_TRACE_H_) || defined(TRACE_HEADER_MULTI_READ) + #define _I915_TRACE_H_ + ++#ifdef CONFIG_PREEMPT_RT ++#define NOTRACE ++#endif ++ + #include + #include + #include diff --git a/debian/patches-rt/0006-locking-rtmutex-Add-a-lockdep-assert-to-catch-potent.patch b/debian/patches-rt/0006-locking-rtmutex-Add-a-lockdep-assert-to-catch-potent.patch new file mode 100644 index 000000000..7d94cdb9d --- /dev/null +++ b/debian/patches-rt/0006-locking-rtmutex-Add-a-lockdep-assert-to-catch-potent.patch @@ -0,0 +1,57 @@ +From: Thomas Gleixner +Date: Fri, 8 Sep 2023 18:22:53 +0200 +Subject: [PATCH 6/7] locking/rtmutex: Add a lockdep assert to catch potential + nested blocking +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +There used to be a BUG_ON(current->pi_blocked_on) in the lock acquisition +functions, but that vanished in one of the rtmutex overhauls. + +Bring it back in form of a lockdep assert to catch code paths which take +rtmutex based locks with current::pi_blocked_on != NULL. + +Reported-by: Crystal Wood +Signed-off-by: Thomas Gleixner +Signed-off-by: "Peter Zijlstra (Intel)" +Signed-off-by: Sebastian Andrzej Siewior +Signed-off-by: Peter Zijlstra (Intel) +Link: https://lkml.kernel.org/r/20230908162254.999499-7-bigeasy@linutronix.de +--- + kernel/locking/rtmutex.c | 2 ++ + kernel/locking/rwbase_rt.c | 2 ++ + kernel/locking/spinlock_rt.c | 2 ++ + 3 files changed, 6 insertions(+) + +--- a/kernel/locking/rtmutex.c ++++ b/kernel/locking/rtmutex.c +@@ -1784,6 +1784,8 @@ static int __sched rt_mutex_slowlock(str + static __always_inline int __rt_mutex_lock(struct rt_mutex_base *lock, + unsigned int state) + { ++ lockdep_assert(!current->pi_blocked_on); ++ + if (likely(rt_mutex_try_acquire(lock))) + return 0; + +--- a/kernel/locking/rwbase_rt.c ++++ b/kernel/locking/rwbase_rt.c +@@ -133,6 +133,8 @@ static int __sched __rwbase_read_lock(st + static __always_inline int rwbase_read_lock(struct rwbase_rt *rwb, + unsigned int state) + { ++ lockdep_assert(!current->pi_blocked_on); ++ + if (rwbase_read_trylock(rwb)) + return 0; + +--- a/kernel/locking/spinlock_rt.c ++++ b/kernel/locking/spinlock_rt.c +@@ -37,6 +37,8 @@ + + static __always_inline void rtlock_lock(struct rt_mutex_base *rtm) + { ++ lockdep_assert(!current->pi_blocked_on); ++ + if (unlikely(!rt_mutex_cmpxchg_acquire(rtm, NULL, current))) + rtlock_slowlock(rtm); + } diff --git a/debian/patches-rt/0006-serial-8250-Use-port-lock-wrappers.patch b/debian/patches-rt/0006-serial-8250-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..d6ee818bf --- /dev/null +++ b/debian/patches-rt/0006-serial-8250-Use-port-lock-wrappers.patch @@ -0,0 +1,465 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:23 +0206 +Subject: [PATCH 006/134] serial: 8250: Use port lock wrappers +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Reviewed-by: Ilpo Järvinen +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-7-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/8250/8250_core.c | 12 ++-- + drivers/tty/serial/8250/8250_port.c | 100 ++++++++++++++++++------------------ + 2 files changed, 56 insertions(+), 56 deletions(-) + +--- a/drivers/tty/serial/8250/8250_core.c ++++ b/drivers/tty/serial/8250/8250_core.c +@@ -259,7 +259,7 @@ static void serial8250_backup_timeout(st + unsigned int iir, ier = 0, lsr; + unsigned long flags; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + /* + * Must disable interrupts or else we risk racing with the interrupt +@@ -292,7 +292,7 @@ static void serial8250_backup_timeout(st + if (up->port.irq) + serial_out(up, UART_IER, ier); + +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + /* Standard timer interval plus 0.2s to keep the port running */ + mod_timer(&up->timer, +@@ -992,11 +992,11 @@ static void serial_8250_overrun_backoff_ + struct uart_port *port = &up->port; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + up->ier |= UART_IER_RLSI | UART_IER_RDI; + up->port.read_status_mask |= UART_LSR_DR; + serial_out(up, UART_IER, up->ier); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /** +@@ -1194,9 +1194,9 @@ void serial8250_unregister_port(int line + if (uart->em485) { + unsigned long flags; + +- spin_lock_irqsave(&uart->port.lock, flags); ++ uart_port_lock_irqsave(&uart->port, &flags); + serial8250_em485_destroy(uart); +- spin_unlock_irqrestore(&uart->port.lock, flags); ++ uart_port_unlock_irqrestore(&uart->port, flags); + } + + uart_remove_one_port(&serial8250_reg, &uart->port); +--- a/drivers/tty/serial/8250/8250_port.c ++++ b/drivers/tty/serial/8250/8250_port.c +@@ -689,7 +689,7 @@ static void serial8250_set_sleep(struct + + if (p->capabilities & UART_CAP_SLEEP) { + /* Synchronize UART_IER access against the console. */ +- spin_lock_irq(&p->port.lock); ++ uart_port_lock_irq(&p->port); + if (p->capabilities & UART_CAP_EFR) { + lcr = serial_in(p, UART_LCR); + efr = serial_in(p, UART_EFR); +@@ -703,7 +703,7 @@ static void serial8250_set_sleep(struct + serial_out(p, UART_EFR, efr); + serial_out(p, UART_LCR, lcr); + } +- spin_unlock_irq(&p->port.lock); ++ uart_port_unlock_irq(&p->port); + } + + serial8250_rpm_put(p); +@@ -746,9 +746,9 @@ static void enable_rsa(struct uart_8250_ + { + if (up->port.type == PORT_RSA) { + if (up->port.uartclk != SERIAL_RSA_BAUD_BASE * 16) { +- spin_lock_irq(&up->port.lock); ++ uart_port_lock_irq(&up->port); + __enable_rsa(up); +- spin_unlock_irq(&up->port.lock); ++ uart_port_unlock_irq(&up->port); + } + if (up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16) + serial_out(up, UART_RSA_FRR, 0); +@@ -768,7 +768,7 @@ static void disable_rsa(struct uart_8250 + + if (up->port.type == PORT_RSA && + up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16) { +- spin_lock_irq(&up->port.lock); ++ uart_port_lock_irq(&up->port); + + mode = serial_in(up, UART_RSA_MSR); + result = !(mode & UART_RSA_MSR_FIFO); +@@ -781,7 +781,7 @@ static void disable_rsa(struct uart_8250 + + if (result) + up->port.uartclk = SERIAL_RSA_BAUD_BASE_LO * 16; +- spin_unlock_irq(&up->port.lock); ++ uart_port_unlock_irq(&up->port); + } + } + #endif /* CONFIG_SERIAL_8250_RSA */ +@@ -1172,7 +1172,7 @@ static void autoconfig(struct uart_8250_ + * + * Synchronize UART_IER access against the console. + */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + up->capabilities = 0; + up->bugs = 0; +@@ -1211,7 +1211,7 @@ static void autoconfig(struct uart_8250_ + /* + * We failed; there's nothing here + */ +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + DEBUG_AUTOCONF("IER test failed (%02x, %02x) ", + scratch2, scratch3); + goto out; +@@ -1235,7 +1235,7 @@ static void autoconfig(struct uart_8250_ + status1 = serial_in(up, UART_MSR) & UART_MSR_STATUS_BITS; + serial8250_out_MCR(up, save_mcr); + if (status1 != (UART_MSR_DCD | UART_MSR_CTS)) { +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + DEBUG_AUTOCONF("LOOP test failed (%02x) ", + status1); + goto out; +@@ -1304,7 +1304,7 @@ static void autoconfig(struct uart_8250_ + serial8250_clear_IER(up); + + out_unlock: +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + /* + * Check if the device is a Fintek F81216A +@@ -1344,9 +1344,9 @@ static void autoconfig_irq(struct uart_8 + probe_irq_off(probe_irq_on()); + save_mcr = serial8250_in_MCR(up); + /* Synchronize UART_IER access against the console. */ +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + save_ier = serial_in(up, UART_IER); +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + serial8250_out_MCR(up, UART_MCR_OUT1 | UART_MCR_OUT2); + + irqs = probe_irq_on(); +@@ -1359,9 +1359,9 @@ static void autoconfig_irq(struct uart_8 + UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2); + } + /* Synchronize UART_IER access against the console. */ +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + serial_out(up, UART_IER, UART_IER_ALL_INTR); +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + serial_in(up, UART_LSR); + serial_in(up, UART_RX); + serial_in(up, UART_IIR); +@@ -1372,9 +1372,9 @@ static void autoconfig_irq(struct uart_8 + + serial8250_out_MCR(up, save_mcr); + /* Synchronize UART_IER access against the console. */ +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + serial_out(up, UART_IER, save_ier); +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + + if (port->flags & UPF_FOURPORT) + outb_p(save_ICP, ICP); +@@ -1442,13 +1442,13 @@ static enum hrtimer_restart serial8250_e + unsigned long flags; + + serial8250_rpm_get(p); +- spin_lock_irqsave(&p->port.lock, flags); ++ uart_port_lock_irqsave(&p->port, &flags); + if (em485->active_timer == &em485->stop_tx_timer) { + p->rs485_stop_tx(p); + em485->active_timer = NULL; + em485->tx_stopped = true; + } +- spin_unlock_irqrestore(&p->port.lock, flags); ++ uart_port_unlock_irqrestore(&p->port, flags); + serial8250_rpm_put(p); + + return HRTIMER_NORESTART; +@@ -1630,12 +1630,12 @@ static enum hrtimer_restart serial8250_e + struct uart_8250_port *p = em485->port; + unsigned long flags; + +- spin_lock_irqsave(&p->port.lock, flags); ++ uart_port_lock_irqsave(&p->port, &flags); + if (em485->active_timer == &em485->start_tx_timer) { + __start_tx(&p->port); + em485->active_timer = NULL; + } +- spin_unlock_irqrestore(&p->port.lock, flags); ++ uart_port_unlock_irqrestore(&p->port, flags); + + return HRTIMER_NORESTART; + } +@@ -1918,7 +1918,7 @@ int serial8250_handle_irq(struct uart_po + if (iir & UART_IIR_NO_INT) + return 0; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + status = serial_lsr_in(up); + +@@ -1988,9 +1988,9 @@ static int serial8250_tx_threshold_handl + if ((iir & UART_IIR_ID) == UART_IIR_THRI) { + struct uart_8250_port *up = up_to_u8250p(port); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + serial8250_tx_chars(up); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + iir = serial_port_in(port, UART_IIR); +@@ -2005,10 +2005,10 @@ static unsigned int serial8250_tx_empty( + + serial8250_rpm_get(up); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + if (!serial8250_tx_dma_running(up) && uart_lsr_tx_empty(serial_lsr_in(up))) + result = TIOCSER_TEMT; +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + serial8250_rpm_put(up); + +@@ -2070,13 +2070,13 @@ static void serial8250_break_ctl(struct + unsigned long flags; + + serial8250_rpm_get(up); +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + if (break_state == -1) + up->lcr |= UART_LCR_SBC; + else + up->lcr &= ~UART_LCR_SBC; + serial_port_out(port, UART_LCR, up->lcr); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + serial8250_rpm_put(up); + } + +@@ -2211,7 +2211,7 @@ int serial8250_do_startup(struct uart_po + * + * Synchronize UART_IER access against the console. + */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + up->acr = 0; + serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B); + serial_port_out(port, UART_EFR, UART_EFR_ECB); +@@ -2221,7 +2221,7 @@ int serial8250_do_startup(struct uart_po + serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B); + serial_port_out(port, UART_EFR, UART_EFR_ECB); + serial_port_out(port, UART_LCR, 0); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + if (port->type == PORT_DA830) { +@@ -2230,10 +2230,10 @@ int serial8250_do_startup(struct uart_po + * + * Synchronize UART_IER access against the console. + */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + serial_port_out(port, UART_IER, 0); + serial_port_out(port, UART_DA830_PWREMU_MGMT, 0); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + mdelay(10); + + /* Enable Tx, Rx and free run mode */ +@@ -2347,7 +2347,7 @@ int serial8250_do_startup(struct uart_po + * + * Synchronize UART_IER access against the console. + */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + wait_for_xmitr(up, UART_LSR_THRE); + serial_port_out_sync(port, UART_IER, UART_IER_THRI); +@@ -2359,7 +2359,7 @@ int serial8250_do_startup(struct uart_po + iir = serial_port_in(port, UART_IIR); + serial_port_out(port, UART_IER, 0); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + if (port->irqflags & IRQF_SHARED) + enable_irq(port->irq); +@@ -2382,7 +2382,7 @@ int serial8250_do_startup(struct uart_po + */ + serial_port_out(port, UART_LCR, UART_LCR_WLEN8); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + if (up->port.flags & UPF_FOURPORT) { + if (!up->port.irq) + up->port.mctrl |= TIOCM_OUT1; +@@ -2428,7 +2428,7 @@ int serial8250_do_startup(struct uart_po + } + + dont_test_tx_en: +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + /* + * Clear the interrupt registers again for luck, and clear the +@@ -2499,17 +2499,17 @@ void serial8250_do_shutdown(struct uart_ + * + * Synchronize UART_IER access against the console. + */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + up->ier = 0; + serial_port_out(port, UART_IER, 0); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + synchronize_irq(port->irq); + + if (up->dma) + serial8250_release_dma(up); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + if (port->flags & UPF_FOURPORT) { + /* reset interrupts on the AST Fourport board */ + inb((port->iobase & 0xfe0) | 0x1f); +@@ -2518,7 +2518,7 @@ void serial8250_do_shutdown(struct uart_ + port->mctrl &= ~TIOCM_OUT2; + + serial8250_set_mctrl(port, port->mctrl); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + /* + * Disable break condition and FIFOs +@@ -2754,14 +2754,14 @@ void serial8250_update_uartclk(struct ua + quot = serial8250_get_divisor(port, baud, &frac); + + serial8250_rpm_get(up); +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + uart_update_timeout(port, termios->c_cflag, baud); + + serial8250_set_divisor(port, baud, quot, frac); + serial_port_out(port, UART_LCR, up->lcr); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + serial8250_rpm_put(up); + + out_unlock: +@@ -2798,7 +2798,7 @@ serial8250_do_set_termios(struct uart_po + * Synchronize UART_IER access against the console. + */ + serial8250_rpm_get(up); +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + up->lcr = cval; /* Save computed LCR */ + +@@ -2901,7 +2901,7 @@ serial8250_do_set_termios(struct uart_po + serial_port_out(port, UART_FCR, up->fcr); /* set fcr */ + } + serial8250_set_mctrl(port, port->mctrl); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + serial8250_rpm_put(up); + + /* Don't rewrite B0 */ +@@ -2924,15 +2924,15 @@ void serial8250_do_set_ldisc(struct uart + { + if (termios->c_line == N_PPS) { + port->flags |= UPF_HARDPPS_CD; +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + serial8250_enable_ms(port); +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + } else { + port->flags &= ~UPF_HARDPPS_CD; + if (!UART_ENABLE_MS(port, termios->c_cflag)) { +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + serial8250_disable_ms(port); +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + } + } + } +@@ -3406,9 +3406,9 @@ void serial8250_console_write(struct uar + touch_nmi_watchdog(); + + if (oops_in_progress) +- locked = spin_trylock_irqsave(&port->lock, flags); ++ locked = uart_port_trylock_irqsave(port, &flags); + else +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* + * First save the IER then disable the interrupts +@@ -3478,7 +3478,7 @@ void serial8250_console_write(struct uar + serial8250_modem_status(up); + + if (locked) +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static unsigned int probe_baud(struct uart_port *port) diff --git a/debian/patches-rt/0007-drm-i915-skip-DRM_I915_LOW_LEVEL_TRACEPOINTS-with-NO.patch b/debian/patches-rt/0007-drm-i915-skip-DRM_I915_LOW_LEVEL_TRACEPOINTS-with-NO.patch new file mode 100644 index 000000000..d784f90a9 --- /dev/null +++ b/debian/patches-rt/0007-drm-i915-skip-DRM_I915_LOW_LEVEL_TRACEPOINTS-with-NO.patch @@ -0,0 +1,29 @@ +From: Sebastian Andrzej Siewior +Date: Wed, 19 Dec 2018 10:47:02 +0100 +Subject: [PATCH 07/10] drm/i915: skip DRM_I915_LOW_LEVEL_TRACEPOINTS with + NOTRACE +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +The order of the header files is important. If this header file is +included after tracepoint.h was included then the NOTRACE here becomes a +nop. Currently this happens for two .c files which use the tracepoitns +behind DRM_I915_LOW_LEVEL_TRACEPOINTS. + +Cc: Steven Rostedt +Signed-off-by: Sebastian Andrzej Siewior +Signed-off-by: Thomas Gleixner +--- + drivers/gpu/drm/i915/i915_trace.h | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +--- a/drivers/gpu/drm/i915/i915_trace.h ++++ b/drivers/gpu/drm/i915/i915_trace.h +@@ -326,7 +326,7 @@ DEFINE_EVENT(i915_request, i915_request_ + TP_ARGS(rq) + ); + +-#if defined(CONFIG_DRM_I915_LOW_LEVEL_TRACEPOINTS) ++#if defined(CONFIG_DRM_I915_LOW_LEVEL_TRACEPOINTS) && !defined(NOTRACE) + DEFINE_EVENT(i915_request, i915_request_guc_submit, + TP_PROTO(struct i915_request *rq), + TP_ARGS(rq) diff --git a/debian/patches-rt/0007-futex-pi-Fix-recursive-rt_mutex-waiter-state.patch b/debian/patches-rt/0007-futex-pi-Fix-recursive-rt_mutex-waiter-state.patch new file mode 100644 index 000000000..76a9b6058 --- /dev/null +++ b/debian/patches-rt/0007-futex-pi-Fix-recursive-rt_mutex-waiter-state.patch @@ -0,0 +1,198 @@ +From: Peter Zijlstra +Date: Fri, 15 Sep 2023 17:19:44 +0200 +Subject: [PATCH 7/7] futex/pi: Fix recursive rt_mutex waiter state +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Some new assertions pointed out that the existing code has nested rt_mutex wait +state in the futex code. + +Specifically, the futex_lock_pi() cancel case uses spin_lock() while there +still is a rt_waiter enqueued for this task, resulting in a state where there +are two waiters for the same task (and task_struct::pi_blocked_on gets +scrambled). + +The reason to take hb->lock at this point is to avoid the wake_futex_pi() +EAGAIN case. + +This happens when futex_top_waiter() and rt_mutex_top_waiter() state becomes +inconsistent. The current rules are such that this inconsistency will not be +observed. + +Notably the case that needs to be avoided is where futex_lock_pi() and +futex_unlock_pi() interleave such that unlock will fail to observe a new +waiter. + +*However* the case at hand is where a waiter is leaving, in this case the race +means a waiter that is going away is not observed -- which is harmless, +provided this race is explicitly handled. + +This is a somewhat dangerous proposition because the converse race is not +observing a new waiter, which must absolutely not happen. But since the race is +valid this cannot be asserted. + +Signed-off-by: Peter Zijlstra (Intel) +Reviewed-by: Thomas Gleixner +Reviewed-by: Sebastian Andrzej Siewior +Tested-by: Sebastian Andrzej Siewior +Link: https://lkml.kernel.org/r/20230915151943.GD6743@noisy.programming.kicks-ass.net +--- + kernel/futex/pi.c | 76 ++++++++++++++++++++++++++++++------------------- + kernel/futex/requeue.c | 6 ++- + 2 files changed, 52 insertions(+), 30 deletions(-) + +--- a/kernel/futex/pi.c ++++ b/kernel/futex/pi.c +@@ -611,29 +611,16 @@ int futex_lock_pi_atomic(u32 __user *uad + /* + * Caller must hold a reference on @pi_state. + */ +-static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_pi_state *pi_state) ++static int wake_futex_pi(u32 __user *uaddr, u32 uval, ++ struct futex_pi_state *pi_state, ++ struct rt_mutex_waiter *top_waiter) + { +- struct rt_mutex_waiter *top_waiter; + struct task_struct *new_owner; + bool postunlock = false; + DEFINE_RT_WAKE_Q(wqh); + u32 curval, newval; + int ret = 0; + +- top_waiter = rt_mutex_top_waiter(&pi_state->pi_mutex); +- if (WARN_ON_ONCE(!top_waiter)) { +- /* +- * As per the comment in futex_unlock_pi() this should not happen. +- * +- * When this happens, give up our locks and try again, giving +- * the futex_lock_pi() instance time to complete, either by +- * waiting on the rtmutex or removing itself from the futex +- * queue. +- */ +- ret = -EAGAIN; +- goto out_unlock; +- } +- + new_owner = top_waiter->task; + + /* +@@ -1046,20 +1033,34 @@ int futex_lock_pi(u32 __user *uaddr, uns + ret = rt_mutex_wait_proxy_lock(&q.pi_state->pi_mutex, to, &rt_waiter); + + cleanup: +- spin_lock(q.lock_ptr); + /* + * If we failed to acquire the lock (deadlock/signal/timeout), we must +- * first acquire the hb->lock before removing the lock from the +- * rt_mutex waitqueue, such that we can keep the hb and rt_mutex wait +- * lists consistent. ++ * must unwind the above, however we canont lock hb->lock because ++ * rt_mutex already has a waiter enqueued and hb->lock can itself try ++ * and enqueue an rt_waiter through rtlock. ++ * ++ * Doing the cleanup without holding hb->lock can cause inconsistent ++ * state between hb and pi_state, but only in the direction of not ++ * seeing a waiter that is leaving. ++ * ++ * See futex_unlock_pi(), it deals with this inconsistency. ++ * ++ * There be dragons here, since we must deal with the inconsistency on ++ * the way out (here), it is impossible to detect/warn about the race ++ * the other way around (missing an incoming waiter). + * +- * In particular; it is important that futex_unlock_pi() can not +- * observe this inconsistency. ++ * What could possibly go wrong... + */ + if (ret && !rt_mutex_cleanup_proxy_lock(&q.pi_state->pi_mutex, &rt_waiter)) + ret = 0; + + /* ++ * Now that the rt_waiter has been dequeued, it is safe to use ++ * spinlock/rtlock (which might enqueue its own rt_waiter) and fix up ++ * the ++ */ ++ spin_lock(q.lock_ptr); ++ /* + * Waiter is unqueued. + */ + rt_mutex_post_schedule(); +@@ -1143,6 +1144,7 @@ int futex_unlock_pi(u32 __user *uaddr, u + top_waiter = futex_top_waiter(hb, &key); + if (top_waiter) { + struct futex_pi_state *pi_state = top_waiter->pi_state; ++ struct rt_mutex_waiter *rt_waiter; + + ret = -EINVAL; + if (!pi_state) +@@ -1155,22 +1157,39 @@ int futex_unlock_pi(u32 __user *uaddr, u + if (pi_state->owner != current) + goto out_unlock; + +- get_pi_state(pi_state); + /* + * By taking wait_lock while still holding hb->lock, we ensure +- * there is no point where we hold neither; and therefore +- * wake_futex_p() must observe a state consistent with what we +- * observed. ++ * there is no point where we hold neither; and thereby ++ * wake_futex_pi() must observe any new waiters. ++ * ++ * Since the cleanup: case in futex_lock_pi() removes the ++ * rt_waiter without holding hb->lock, it is possible for ++ * wake_futex_pi() to not find a waiter while the above does, ++ * in this case the waiter is on the way out and it can be ++ * ignored. + * + * In particular; this forces __rt_mutex_start_proxy() to + * complete such that we're guaranteed to observe the +- * rt_waiter. Also see the WARN in wake_futex_pi(). ++ * rt_waiter. + */ + raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock); ++ ++ /* ++ * Futex vs rt_mutex waiter state -- if there are no rt_mutex ++ * waiters even though futex thinks there are, then the waiter ++ * is leaving and the uncontended path is safe to take. ++ */ ++ rt_waiter = rt_mutex_top_waiter(&pi_state->pi_mutex); ++ if (!rt_waiter) { ++ raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock); ++ goto do_uncontended; ++ } ++ ++ get_pi_state(pi_state); + spin_unlock(&hb->lock); + + /* drops pi_state->pi_mutex.wait_lock */ +- ret = wake_futex_pi(uaddr, uval, pi_state); ++ ret = wake_futex_pi(uaddr, uval, pi_state, rt_waiter); + + put_pi_state(pi_state); + +@@ -1198,6 +1217,7 @@ int futex_unlock_pi(u32 __user *uaddr, u + return ret; + } + ++do_uncontended: + /* + * We have no kernel internal state, i.e. no waiters in the + * kernel. Waiters which are about to queue themselves are stuck +--- a/kernel/futex/requeue.c ++++ b/kernel/futex/requeue.c +@@ -850,11 +850,13 @@ int futex_wait_requeue_pi(u32 __user *ua + pi_mutex = &q.pi_state->pi_mutex; + ret = rt_mutex_wait_proxy_lock(pi_mutex, to, &rt_waiter); + +- /* Current is not longer pi_blocked_on */ +- spin_lock(q.lock_ptr); ++ /* ++ * See futex_unlock_pi()'s cleanup: comment. ++ */ + if (ret && !rt_mutex_cleanup_proxy_lock(pi_mutex, &rt_waiter)) + ret = 0; + ++ spin_lock(q.lock_ptr); + debug_rt_mutex_free_waiter(&rt_waiter); + /* + * Fixup the pi_state owner and possibly acquire the lock if we diff --git a/debian/patches-rt/0007-serial-8250_dma-Use-port-lock-wrappers.patch b/debian/patches-rt/0007-serial-8250_dma-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..bc8686e89 --- /dev/null +++ b/debian/patches-rt/0007-serial-8250_dma-Use-port-lock-wrappers.patch @@ -0,0 +1,80 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:24 +0206 +Subject: [PATCH 007/134] serial: 8250_dma: Use port lock wrappers +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Reviewed-by: Ilpo Järvinen +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-8-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/8250/8250_dma.c | 8 ++++---- + 1 file changed, 4 insertions(+), 4 deletions(-) + +--- a/drivers/tty/serial/8250/8250_dma.c ++++ b/drivers/tty/serial/8250/8250_dma.c +@@ -22,7 +22,7 @@ static void __dma_tx_complete(void *para + dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr, + UART_XMIT_SIZE, DMA_TO_DEVICE); + +- spin_lock_irqsave(&p->port.lock, flags); ++ uart_port_lock_irqsave(&p->port, &flags); + + dma->tx_running = 0; + +@@ -35,7 +35,7 @@ static void __dma_tx_complete(void *para + if (ret || !dma->tx_running) + serial8250_set_THRI(p); + +- spin_unlock_irqrestore(&p->port.lock, flags); ++ uart_port_unlock_irqrestore(&p->port, flags); + } + + static void __dma_rx_complete(struct uart_8250_port *p) +@@ -70,7 +70,7 @@ static void dma_rx_complete(void *param) + struct uart_8250_dma *dma = p->dma; + unsigned long flags; + +- spin_lock_irqsave(&p->port.lock, flags); ++ uart_port_lock_irqsave(&p->port, &flags); + if (dma->rx_running) + __dma_rx_complete(p); + +@@ -80,7 +80,7 @@ static void dma_rx_complete(void *param) + */ + if (!dma->rx_running && (serial_lsr_in(p) & UART_LSR_DR)) + p->dma->rx_dma(p); +- spin_unlock_irqrestore(&p->port.lock, flags); ++ uart_port_unlock_irqrestore(&p->port, flags); + } + + int serial8250_tx_dma(struct uart_8250_port *p) diff --git a/debian/patches-rt/0008-drm-i915-gt-Queue-and-wait-for-the-irq_work-item.patch b/debian/patches-rt/0008-drm-i915-gt-Queue-and-wait-for-the-irq_work-item.patch new file mode 100644 index 000000000..0322ae154 --- /dev/null +++ b/debian/patches-rt/0008-drm-i915-gt-Queue-and-wait-for-the-irq_work-item.patch @@ -0,0 +1,42 @@ +From: Sebastian Andrzej Siewior +Date: Wed, 8 Sep 2021 17:18:00 +0200 +Subject: [PATCH 08/10] drm/i915/gt: Queue and wait for the irq_work item. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Disabling interrupts and invoking the irq_work function directly breaks +on PREEMPT_RT. +PREEMPT_RT does not invoke all irq_work from hardirq context because +some of the user have spinlock_t locking in the callback function. +These locks are then turned into a sleeping locks which can not be +acquired with disabled interrupts. + +Using irq_work_queue() has the benefit that the irqwork will be invoked +in the regular context. In general there is "no" delay between enqueuing +the callback and its invocation because the interrupt is raised right +away on architectures which support it (which includes x86). + +Use irq_work_queue() + irq_work_sync() instead invoking the callback +directly. + +Reported-by: Clark Williams +Signed-off-by: Sebastian Andrzej Siewior +Reviewed-by: Maarten Lankhorst +--- + drivers/gpu/drm/i915/gt/intel_breadcrumbs.c | 5 ++--- + 1 file changed, 2 insertions(+), 3 deletions(-) + +--- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c ++++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c +@@ -312,10 +312,9 @@ void __intel_breadcrumbs_park(struct int + /* Kick the work once more to drain the signalers, and disarm the irq */ + irq_work_sync(&b->irq_work); + while (READ_ONCE(b->irq_armed) && !atomic_read(&b->active)) { +- local_irq_disable(); +- signal_irq_work(&b->irq_work); +- local_irq_enable(); ++ irq_work_queue(&b->irq_work); + cond_resched(); ++ irq_work_sync(&b->irq_work); + } + } + diff --git a/debian/patches-rt/0008-serial-8250_dw-Use-port-lock-wrappers.patch b/debian/patches-rt/0008-serial-8250_dw-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..d5394fc7a --- /dev/null +++ b/debian/patches-rt/0008-serial-8250_dw-Use-port-lock-wrappers.patch @@ -0,0 +1,69 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:25 +0206 +Subject: [PATCH 008/134] serial: 8250_dw: Use port lock wrappers +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Reviewed-by: Ilpo Järvinen +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-9-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/8250/8250_dw.c | 8 ++++---- + 1 file changed, 4 insertions(+), 4 deletions(-) + +--- a/drivers/tty/serial/8250/8250_dw.c ++++ b/drivers/tty/serial/8250/8250_dw.c +@@ -263,20 +263,20 @@ static int dw8250_handle_irq(struct uart + * so we limit the workaround only to non-DMA mode. + */ + if (!up->dma && rx_timeout) { +- spin_lock_irqsave(&p->lock, flags); ++ uart_port_lock_irqsave(p, &flags); + status = serial_lsr_in(up); + + if (!(status & (UART_LSR_DR | UART_LSR_BI))) + (void) p->serial_in(p, UART_RX); + +- spin_unlock_irqrestore(&p->lock, flags); ++ uart_port_unlock_irqrestore(p, flags); + } + + /* Manually stop the Rx DMA transfer when acting as flow controller */ + if (quirks & DW_UART_QUIRK_IS_DMA_FC && up->dma && up->dma->rx_running && rx_timeout) { +- spin_lock_irqsave(&p->lock, flags); ++ uart_port_lock_irqsave(p, &flags); + status = serial_lsr_in(up); +- spin_unlock_irqrestore(&p->lock, flags); ++ uart_port_unlock_irqrestore(p, flags); + + if (status & (UART_LSR_DR | UART_LSR_BI)) { + dw8250_writel_ext(p, RZN1_UART_RDMACR, 0); diff --git a/debian/patches-rt/0009-drm-i915-gt-Use-spin_lock_irq-instead-of-local_irq_d.patch b/debian/patches-rt/0009-drm-i915-gt-Use-spin_lock_irq-instead-of-local_irq_d.patch new file mode 100644 index 000000000..3245e145f --- /dev/null +++ b/debian/patches-rt/0009-drm-i915-gt-Use-spin_lock_irq-instead-of-local_irq_d.patch @@ -0,0 +1,89 @@ +From: Sebastian Andrzej Siewior +Date: Wed, 8 Sep 2021 19:03:41 +0200 +Subject: [PATCH 09/10] drm/i915/gt: Use spin_lock_irq() instead of + local_irq_disable() + spin_lock() +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +execlists_dequeue() is invoked from a function which uses +local_irq_disable() to disable interrupts so the spin_lock() behaves +like spin_lock_irq(). +This breaks PREEMPT_RT because local_irq_disable() + spin_lock() is not +the same as spin_lock_irq(). + +execlists_dequeue_irq() and execlists_dequeue() has each one caller +only. If intel_engine_cs::active::lock is acquired and released with the +_irq suffix then it behaves almost as if execlists_dequeue() would be +invoked with disabled interrupts. The difference is the last part of the +function which is then invoked with enabled interrupts. +I can't tell if this makes a difference. From looking at it, it might +work to move the last unlock at the end of the function as I didn't find +anything that would acquire the lock again. + +Reported-by: Clark Williams +Signed-off-by: Sebastian Andrzej Siewior +Reviewed-by: Maarten Lankhorst +--- + drivers/gpu/drm/i915/gt/intel_execlists_submission.c | 17 +++++------------ + 1 file changed, 5 insertions(+), 12 deletions(-) + +--- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c ++++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c +@@ -1303,7 +1303,7 @@ static void execlists_dequeue(struct int + * and context switches) submission. + */ + +- spin_lock(&sched_engine->lock); ++ spin_lock_irq(&sched_engine->lock); + + /* + * If the queue is higher priority than the last +@@ -1403,7 +1403,7 @@ static void execlists_dequeue(struct int + * Even if ELSP[1] is occupied and not worthy + * of timeslices, our queue might be. + */ +- spin_unlock(&sched_engine->lock); ++ spin_unlock_irq(&sched_engine->lock); + return; + } + } +@@ -1429,7 +1429,7 @@ static void execlists_dequeue(struct int + + if (last && !can_merge_rq(last, rq)) { + spin_unlock(&ve->base.sched_engine->lock); +- spin_unlock(&engine->sched_engine->lock); ++ spin_unlock_irq(&engine->sched_engine->lock); + return; /* leave this for another sibling */ + } + +@@ -1591,7 +1591,7 @@ static void execlists_dequeue(struct int + */ + sched_engine->queue_priority_hint = queue_prio(sched_engine); + i915_sched_engine_reset_on_empty(sched_engine); +- spin_unlock(&sched_engine->lock); ++ spin_unlock_irq(&sched_engine->lock); + + /* + * We can skip poking the HW if we ended up with exactly the same set +@@ -1617,13 +1617,6 @@ static void execlists_dequeue(struct int + } + } + +-static void execlists_dequeue_irq(struct intel_engine_cs *engine) +-{ +- local_irq_disable(); /* Suspend interrupts across request submission */ +- execlists_dequeue(engine); +- local_irq_enable(); /* flush irq_work (e.g. breadcrumb enabling) */ +-} +- + static void clear_ports(struct i915_request **ports, int count) + { + memset_p((void **)ports, NULL, count); +@@ -2478,7 +2471,7 @@ static void execlists_submission_tasklet + } + + if (!engine->execlists.pending[0]) { +- execlists_dequeue_irq(engine); ++ execlists_dequeue(engine); + start_timeslice(engine); + } + diff --git a/debian/patches-rt/0009-serial-8250_exar-Use-port-lock-wrappers.patch b/debian/patches-rt/0009-serial-8250_exar-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..80c37fba6 --- /dev/null +++ b/debian/patches-rt/0009-serial-8250_exar-Use-port-lock-wrappers.patch @@ -0,0 +1,52 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:26 +0206 +Subject: [PATCH 009/134] serial: 8250_exar: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-10-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/8250/8250_exar.c | 4 ++-- + 1 file changed, 2 insertions(+), 2 deletions(-) + +--- a/drivers/tty/serial/8250/8250_exar.c ++++ b/drivers/tty/serial/8250/8250_exar.c +@@ -201,9 +201,9 @@ static int xr17v35x_startup(struct uart_ + * + * Synchronize UART_IER access against the console. + */ +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + serial_port_out(port, UART_IER, 0); +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + + return serial8250_do_startup(port); + } diff --git a/debian/patches-rt/0010-drm-i915-Drop-the-irqs_disabled-check.patch b/debian/patches-rt/0010-drm-i915-Drop-the-irqs_disabled-check.patch new file mode 100644 index 000000000..83a516ce8 --- /dev/null +++ b/debian/patches-rt/0010-drm-i915-Drop-the-irqs_disabled-check.patch @@ -0,0 +1,39 @@ +From: Sebastian Andrzej Siewior +Date: Fri, 1 Oct 2021 20:01:03 +0200 +Subject: [PATCH 10/10] drm/i915: Drop the irqs_disabled() check +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +The !irqs_disabled() check triggers on PREEMPT_RT even with +i915_sched_engine::lock acquired. The reason is the lock is transformed +into a sleeping lock on PREEMPT_RT and does not disable interrupts. + +There is no need to check for disabled interrupts. The lockdep +annotation below already check if the lock has been acquired by the +caller and will yell if the interrupts are not disabled. + +Remove the !irqs_disabled() check. + +Reported-by: Maarten Lankhorst +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/gpu/drm/i915/i915_request.c | 2 -- + 1 file changed, 2 deletions(-) + +--- a/drivers/gpu/drm/i915/i915_request.c ++++ b/drivers/gpu/drm/i915/i915_request.c +@@ -609,7 +609,6 @@ bool __i915_request_submit(struct i915_r + + RQ_TRACE(request, "\n"); + +- GEM_BUG_ON(!irqs_disabled()); + lockdep_assert_held(&engine->sched_engine->lock); + + /* +@@ -718,7 +717,6 @@ void __i915_request_unsubmit(struct i915 + */ + RQ_TRACE(request, "\n"); + +- GEM_BUG_ON(!irqs_disabled()); + lockdep_assert_held(&engine->sched_engine->lock); + + /* diff --git a/debian/patches-rt/0010-serial-8250_fsl-Use-port-lock-wrappers.patch b/debian/patches-rt/0010-serial-8250_fsl-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..abe7c81a9 --- /dev/null +++ b/debian/patches-rt/0010-serial-8250_fsl-Use-port-lock-wrappers.patch @@ -0,0 +1,63 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:27 +0206 +Subject: [PATCH 010/134] serial: 8250_fsl: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-11-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/8250/8250_fsl.c | 6 +++--- + 1 file changed, 3 insertions(+), 3 deletions(-) + +--- a/drivers/tty/serial/8250/8250_fsl.c ++++ b/drivers/tty/serial/8250/8250_fsl.c +@@ -30,11 +30,11 @@ int fsl8250_handle_irq(struct uart_port + unsigned int iir; + struct uart_8250_port *up = up_to_u8250p(port); + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + iir = port->serial_in(port, UART_IIR); + if (iir & UART_IIR_NO_INT) { +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + return 0; + } + +@@ -54,7 +54,7 @@ int fsl8250_handle_irq(struct uart_port + if (unlikely(up->lsr_saved_flags & UART_LSR_BI)) { + up->lsr_saved_flags &= ~UART_LSR_BI; + port->serial_in(port, UART_RX); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + return 1; + } + diff --git a/debian/patches-rt/0011-serial-8250_mtk-Use-port-lock-wrappers.patch b/debian/patches-rt/0011-serial-8250_mtk-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..a66818204 --- /dev/null +++ b/debian/patches-rt/0011-serial-8250_mtk-Use-port-lock-wrappers.patch @@ -0,0 +1,77 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:28 +0206 +Subject: [PATCH 011/134] serial: 8250_mtk: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Reviewed-by: Chen-Yu Tsai +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-12-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/8250/8250_mtk.c | 8 ++++---- + 1 file changed, 4 insertions(+), 4 deletions(-) + +--- a/drivers/tty/serial/8250/8250_mtk.c ++++ b/drivers/tty/serial/8250/8250_mtk.c +@@ -102,7 +102,7 @@ static void mtk8250_dma_rx_complete(void + if (data->rx_status == DMA_RX_SHUTDOWN) + return; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); + total = dma->rx_size - state.residue; +@@ -128,7 +128,7 @@ static void mtk8250_dma_rx_complete(void + + mtk8250_rx_dma(up); + +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static void mtk8250_rx_dma(struct uart_8250_port *up) +@@ -368,7 +368,7 @@ mtk8250_set_termios(struct uart_port *po + * Ok, we're now changing the port state. Do it with + * interrupts disabled. + */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* + * Update the per-port timeout. +@@ -416,7 +416,7 @@ mtk8250_set_termios(struct uart_port *po + if (uart_console(port)) + up->port.cons->cflag = termios->c_cflag; + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + /* Don't rewrite B0 */ + if (tty_termios_baud_rate(termios)) + tty_termios_encode_baud_rate(termios, baud, baud); diff --git a/debian/patches-rt/0012-serial-8250_omap-Use-port-lock-wrappers.patch b/debian/patches-rt/0012-serial-8250_omap-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..10ebd70ea --- /dev/null +++ b/debian/patches-rt/0012-serial-8250_omap-Use-port-lock-wrappers.patch @@ -0,0 +1,236 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:29 +0206 +Subject: [PATCH 012/134] serial: 8250_omap: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-13-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/8250/8250_omap.c | 52 ++++++++++++++++++------------------ + 1 file changed, 26 insertions(+), 26 deletions(-) + +--- a/drivers/tty/serial/8250/8250_omap.c ++++ b/drivers/tty/serial/8250/8250_omap.c +@@ -401,7 +401,7 @@ static void omap_8250_set_termios(struct + * interrupts disabled. + */ + pm_runtime_get_sync(port->dev); +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + + /* + * Update the per-port timeout. +@@ -504,7 +504,7 @@ static void omap_8250_set_termios(struct + } + omap8250_restore_regs(up); + +- spin_unlock_irq(&up->port.lock); ++ uart_port_unlock_irq(&up->port); + pm_runtime_mark_last_busy(port->dev); + pm_runtime_put_autosuspend(port->dev); + +@@ -529,7 +529,7 @@ static void omap_8250_pm(struct uart_por + pm_runtime_get_sync(port->dev); + + /* Synchronize UART_IER access against the console. */ +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + + serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); + efr = serial_in(up, UART_EFR); +@@ -541,7 +541,7 @@ static void omap_8250_pm(struct uart_por + serial_out(up, UART_EFR, efr); + serial_out(up, UART_LCR, 0); + +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + + pm_runtime_mark_last_busy(port->dev); + pm_runtime_put_autosuspend(port->dev); +@@ -660,7 +660,7 @@ static irqreturn_t omap8250_irq(int irq, + unsigned long delay; + + /* Synchronize UART_IER access against the console. */ +- spin_lock(&port->lock); ++ uart_port_lock(port); + up->ier = port->serial_in(port, UART_IER); + if (up->ier & (UART_IER_RLSI | UART_IER_RDI)) { + port->ops->stop_rx(port); +@@ -670,7 +670,7 @@ static irqreturn_t omap8250_irq(int irq, + */ + cancel_delayed_work(&up->overrun_backoff); + } +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + delay = msecs_to_jiffies(up->overrun_backoff_time_ms); + schedule_delayed_work(&up->overrun_backoff, delay); +@@ -717,10 +717,10 @@ static int omap_8250_startup(struct uart + } + + /* Synchronize UART_IER access against the console. */ +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + up->ier = UART_IER_RLSI | UART_IER_RDI; + serial_out(up, UART_IER, up->ier); +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + + #ifdef CONFIG_PM + up->capabilities |= UART_CAP_RPM; +@@ -733,9 +733,9 @@ static int omap_8250_startup(struct uart + serial_out(up, UART_OMAP_WER, priv->wer); + + if (up->dma && !(priv->habit & UART_HAS_EFR2)) { +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + up->dma->rx_dma(up); +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + } + + enable_irq(up->port.irq); +@@ -761,10 +761,10 @@ static void omap_8250_shutdown(struct ua + serial_out(up, UART_OMAP_EFR2, 0x0); + + /* Synchronize UART_IER access against the console. */ +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + up->ier = 0; + serial_out(up, UART_IER, 0); +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + disable_irq_nosync(up->port.irq); + dev_pm_clear_wake_irq(port->dev); + +@@ -789,10 +789,10 @@ static void omap_8250_throttle(struct ua + + pm_runtime_get_sync(port->dev); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + port->ops->stop_rx(port); + priv->throttled = true; +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + pm_runtime_mark_last_busy(port->dev); + pm_runtime_put_autosuspend(port->dev); +@@ -807,14 +807,14 @@ static void omap_8250_unthrottle(struct + pm_runtime_get_sync(port->dev); + + /* Synchronize UART_IER access against the console. */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + priv->throttled = false; + if (up->dma) + up->dma->rx_dma(up); + up->ier |= UART_IER_RLSI | UART_IER_RDI; + port->read_status_mask |= UART_LSR_DR; + serial_out(up, UART_IER, up->ier); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + pm_runtime_mark_last_busy(port->dev); + pm_runtime_put_autosuspend(port->dev); +@@ -958,7 +958,7 @@ static void __dma_rx_complete(void *para + unsigned long flags; + + /* Synchronize UART_IER access against the console. */ +- spin_lock_irqsave(&p->port.lock, flags); ++ uart_port_lock_irqsave(&p->port, &flags); + + /* + * If the tx status is not DMA_COMPLETE, then this is a delayed +@@ -967,7 +967,7 @@ static void __dma_rx_complete(void *para + */ + if (dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state) != + DMA_COMPLETE) { +- spin_unlock_irqrestore(&p->port.lock, flags); ++ uart_port_unlock_irqrestore(&p->port, flags); + return; + } + __dma_rx_do_complete(p); +@@ -978,7 +978,7 @@ static void __dma_rx_complete(void *para + omap_8250_rx_dma(p); + } + +- spin_unlock_irqrestore(&p->port.lock, flags); ++ uart_port_unlock_irqrestore(&p->port, flags); + } + + static void omap_8250_rx_dma_flush(struct uart_8250_port *p) +@@ -1083,7 +1083,7 @@ static void omap_8250_dma_tx_complete(vo + dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr, + UART_XMIT_SIZE, DMA_TO_DEVICE); + +- spin_lock_irqsave(&p->port.lock, flags); ++ uart_port_lock_irqsave(&p->port, &flags); + + dma->tx_running = 0; + +@@ -1112,7 +1112,7 @@ static void omap_8250_dma_tx_complete(vo + serial8250_set_THRI(p); + } + +- spin_unlock_irqrestore(&p->port.lock, flags); ++ uart_port_unlock_irqrestore(&p->port, flags); + } + + static int omap_8250_tx_dma(struct uart_8250_port *p) +@@ -1278,7 +1278,7 @@ static int omap_8250_dma_handle_irq(stru + return IRQ_HANDLED; + } + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + status = serial_port_in(port, UART_LSR); + +@@ -1756,15 +1756,15 @@ static int omap8250_runtime_resume(struc + up = serial8250_get_port(priv->line); + + if (up && omap8250_lost_context(up)) { +- spin_lock_irq(&up->port.lock); ++ uart_port_lock_irq(&up->port); + omap8250_restore_regs(up); +- spin_unlock_irq(&up->port.lock); ++ uart_port_unlock_irq(&up->port); + } + + if (up && up->dma && up->dma->rxchan && !(priv->habit & UART_HAS_EFR2)) { +- spin_lock_irq(&up->port.lock); ++ uart_port_lock_irq(&up->port); + omap_8250_rx_dma(up); +- spin_unlock_irq(&up->port.lock); ++ uart_port_unlock_irq(&up->port); + } + + priv->latency = priv->calc_latency; diff --git a/debian/patches-rt/0013-serial-8250_pci1xxxx-Use-port-lock-wrappers.patch b/debian/patches-rt/0013-serial-8250_pci1xxxx-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..291638769 --- /dev/null +++ b/debian/patches-rt/0013-serial-8250_pci1xxxx-Use-port-lock-wrappers.patch @@ -0,0 +1,66 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:30 +0206 +Subject: [PATCH 013/134] serial: 8250_pci1xxxx: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-14-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/8250/8250_pci1xxxx.c | 8 ++++---- + 1 file changed, 4 insertions(+), 4 deletions(-) + +--- a/drivers/tty/serial/8250/8250_pci1xxxx.c ++++ b/drivers/tty/serial/8250/8250_pci1xxxx.c +@@ -225,10 +225,10 @@ static bool pci1xxxx_port_suspend(int li + if (port->suspended == 0 && port->dev) { + wakeup_mask = readb(up->port.membase + UART_WAKE_MASK_REG); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + port->mctrl &= ~TIOCM_OUT2; + port->ops->set_mctrl(port, port->mctrl); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + ret = (wakeup_mask & UART_WAKE_SRCS) != UART_WAKE_SRCS; + } +@@ -251,10 +251,10 @@ static void pci1xxxx_port_resume(int lin + writeb(UART_WAKE_SRCS, port->membase + UART_WAKE_REG); + + if (port->suspended == 0) { +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + port->mctrl |= TIOCM_OUT2; + port->ops->set_mctrl(port, port->mctrl); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + mutex_unlock(&tport->mutex); + } diff --git a/debian/patches-rt/0014-serial-altera_jtaguart-Use-port-lock-wrappers.patch b/debian/patches-rt/0014-serial-altera_jtaguart-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..46dbf785d --- /dev/null +++ b/debian/patches-rt/0014-serial-altera_jtaguart-Use-port-lock-wrappers.patch @@ -0,0 +1,133 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:31 +0206 +Subject: [PATCH 014/134] serial: altera_jtaguart: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-15-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/altera_jtaguart.c | 28 ++++++++++++++-------------- + 1 file changed, 14 insertions(+), 14 deletions(-) + +--- a/drivers/tty/serial/altera_jtaguart.c ++++ b/drivers/tty/serial/altera_jtaguart.c +@@ -147,14 +147,14 @@ static irqreturn_t altera_jtaguart_inter + isr = (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) >> + ALTERA_JTAGUART_CONTROL_RI_OFF) & port->read_status_mask; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + if (isr & ALTERA_JTAGUART_CONTROL_RE_MSK) + altera_jtaguart_rx_chars(port); + if (isr & ALTERA_JTAGUART_CONTROL_WE_MSK) + altera_jtaguart_tx_chars(port); + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return IRQ_RETVAL(isr); + } +@@ -180,14 +180,14 @@ static int altera_jtaguart_startup(struc + return ret; + } + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Enable RX interrupts now */ + port->read_status_mask = ALTERA_JTAGUART_CONTROL_RE_MSK; + writel(port->read_status_mask, + port->membase + ALTERA_JTAGUART_CONTROL_REG); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return 0; + } +@@ -196,14 +196,14 @@ static void altera_jtaguart_shutdown(str + { + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Disable all interrupts now */ + port->read_status_mask = 0; + writel(port->read_status_mask, + port->membase + ALTERA_JTAGUART_CONTROL_REG); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + free_irq(port->irq, port); + } +@@ -264,33 +264,33 @@ static void altera_jtaguart_console_putc + unsigned long flags; + u32 status; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + while (!altera_jtaguart_tx_space(port, &status)) { +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + if ((status & ALTERA_JTAGUART_CONTROL_AC_MSK) == 0) { + return; /* no connection activity */ + } + + cpu_relax(); +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + } + writel(c, port->membase + ALTERA_JTAGUART_DATA_REG); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + #else + static void altera_jtaguart_console_putc(struct uart_port *port, unsigned char c) + { + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + while (!altera_jtaguart_tx_space(port, NULL)) { +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + cpu_relax(); +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + } + writel(c, port->membase + ALTERA_JTAGUART_DATA_REG); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + #endif + diff --git a/debian/patches-rt/0015-serial-altera_uart-Use-port-lock-wrappers.patch b/debian/patches-rt/0015-serial-altera_uart-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..95e2c031f --- /dev/null +++ b/debian/patches-rt/0015-serial-altera_uart-Use-port-lock-wrappers.patch @@ -0,0 +1,116 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:32 +0206 +Subject: [PATCH 015/134] serial: altera_uart: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-16-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/altera_uart.c | 20 ++++++++++---------- + 1 file changed, 10 insertions(+), 10 deletions(-) + +--- a/drivers/tty/serial/altera_uart.c ++++ b/drivers/tty/serial/altera_uart.c +@@ -164,13 +164,13 @@ static void altera_uart_break_ctl(struct + struct altera_uart *pp = container_of(port, struct altera_uart, port); + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + if (break_state == -1) + pp->imr |= ALTERA_UART_CONTROL_TRBK_MSK; + else + pp->imr &= ~ALTERA_UART_CONTROL_TRBK_MSK; + altera_uart_update_ctrl_reg(pp); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void altera_uart_set_termios(struct uart_port *port, +@@ -187,10 +187,10 @@ static void altera_uart_set_termios(stru + tty_termios_copy_hw(termios, old); + tty_termios_encode_baud_rate(termios, baud, baud); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + uart_update_timeout(port, termios->c_cflag, baud); + altera_uart_writel(port, baudclk, ALTERA_UART_DIVISOR_REG); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + /* + * FIXME: port->read_status_mask and port->ignore_status_mask +@@ -264,12 +264,12 @@ static irqreturn_t altera_uart_interrupt + + isr = altera_uart_readl(port, ALTERA_UART_STATUS_REG) & pp->imr; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + if (isr & ALTERA_UART_STATUS_RRDY_MSK) + altera_uart_rx_chars(port); + if (isr & ALTERA_UART_STATUS_TRDY_MSK) + altera_uart_tx_chars(port); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return IRQ_RETVAL(isr); + } +@@ -313,13 +313,13 @@ static int altera_uart_startup(struct ua + } + } + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Enable RX interrupts now */ + pp->imr = ALTERA_UART_CONTROL_RRDY_MSK; + altera_uart_update_ctrl_reg(pp); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return 0; + } +@@ -329,13 +329,13 @@ static void altera_uart_shutdown(struct + struct altera_uart *pp = container_of(port, struct altera_uart, port); + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Disable all interrupts now */ + pp->imr = 0; + altera_uart_update_ctrl_reg(pp); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + if (port->irq) + free_irq(port->irq, port); diff --git a/debian/patches-rt/0016-serial-amba-pl010-Use-port-lock-wrappers.patch b/debian/patches-rt/0016-serial-amba-pl010-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..f3ba735bf --- /dev/null +++ b/debian/patches-rt/0016-serial-amba-pl010-Use-port-lock-wrappers.patch @@ -0,0 +1,112 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:33 +0206 +Subject: [PATCH 016/134] serial: amba-pl010: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-17-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/amba-pl010.c | 20 ++++++++++---------- + 1 file changed, 10 insertions(+), 10 deletions(-) + +--- a/drivers/tty/serial/amba-pl010.c ++++ b/drivers/tty/serial/amba-pl010.c +@@ -207,7 +207,7 @@ static irqreturn_t pl010_int(int irq, vo + unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT; + int handled = 0; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + status = readb(port->membase + UART010_IIR); + if (status) { +@@ -228,7 +228,7 @@ static irqreturn_t pl010_int(int irq, vo + handled = 1; + } + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return IRQ_RETVAL(handled); + } +@@ -270,14 +270,14 @@ static void pl010_break_ctl(struct uart_ + unsigned long flags; + unsigned int lcr_h; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + lcr_h = readb(port->membase + UART010_LCRH); + if (break_state == -1) + lcr_h |= UART01x_LCRH_BRK; + else + lcr_h &= ~UART01x_LCRH_BRK; + writel(lcr_h, port->membase + UART010_LCRH); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int pl010_startup(struct uart_port *port) +@@ -385,7 +385,7 @@ pl010_set_termios(struct uart_port *port + if (port->fifosize > 1) + lcr_h |= UART01x_LCRH_FEN; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* + * Update the per-port timeout. +@@ -438,22 +438,22 @@ pl010_set_termios(struct uart_port *port + writel(lcr_h, port->membase + UART010_LCRH); + writel(old_cr, port->membase + UART010_CR); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void pl010_set_ldisc(struct uart_port *port, struct ktermios *termios) + { + if (termios->c_line == N_PPS) { + port->flags |= UPF_HARDPPS_CD; +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + pl010_enable_ms(port); +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + } else { + port->flags &= ~UPF_HARDPPS_CD; + if (!UART_ENABLE_MS(port, termios->c_cflag)) { +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + pl010_disable_ms(port); +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + } + } + } diff --git a/debian/patches-rt/0017-serial-amba-pl011-Use-port-lock-wrappers.patch b/debian/patches-rt/0017-serial-amba-pl011-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..2a5e3a85e --- /dev/null +++ b/debian/patches-rt/0017-serial-amba-pl011-Use-port-lock-wrappers.patch @@ -0,0 +1,327 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:34 +0206 +Subject: [PATCH 017/134] serial: amba-pl011: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-18-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/amba-pl011.c | 72 ++++++++++++++++++++-------------------- + 1 file changed, 36 insertions(+), 36 deletions(-) + +--- a/drivers/tty/serial/amba-pl011.c ++++ b/drivers/tty/serial/amba-pl011.c +@@ -347,9 +347,9 @@ static int pl011_fifo_to_tty(struct uart + flag = TTY_FRAME; + } + +- spin_unlock(&uap->port.lock); ++ uart_port_unlock(&uap->port); + sysrq = uart_handle_sysrq_char(&uap->port, ch & 255); +- spin_lock(&uap->port.lock); ++ uart_port_lock(&uap->port); + + if (!sysrq) + uart_insert_char(&uap->port, ch, UART011_DR_OE, ch, flag); +@@ -544,7 +544,7 @@ static void pl011_dma_tx_callback(void * + unsigned long flags; + u16 dmacr; + +- spin_lock_irqsave(&uap->port.lock, flags); ++ uart_port_lock_irqsave(&uap->port, &flags); + if (uap->dmatx.queued) + dma_unmap_single(dmatx->chan->device->dev, dmatx->dma, + dmatx->len, DMA_TO_DEVICE); +@@ -565,7 +565,7 @@ static void pl011_dma_tx_callback(void * + if (!(dmacr & UART011_TXDMAE) || uart_tx_stopped(&uap->port) || + uart_circ_empty(&uap->port.state->xmit)) { + uap->dmatx.queued = false; +- spin_unlock_irqrestore(&uap->port.lock, flags); ++ uart_port_unlock_irqrestore(&uap->port, flags); + return; + } + +@@ -576,7 +576,7 @@ static void pl011_dma_tx_callback(void * + */ + pl011_start_tx_pio(uap); + +- spin_unlock_irqrestore(&uap->port.lock, flags); ++ uart_port_unlock_irqrestore(&uap->port, flags); + } + + /* +@@ -1004,7 +1004,7 @@ static void pl011_dma_rx_callback(void * + * routine to flush out the secondary DMA buffer while + * we immediately trigger the next DMA job. + */ +- spin_lock_irq(&uap->port.lock); ++ uart_port_lock_irq(&uap->port); + /* + * Rx data can be taken by the UART interrupts during + * the DMA irq handler. So we check the residue here. +@@ -1020,7 +1020,7 @@ static void pl011_dma_rx_callback(void * + ret = pl011_dma_rx_trigger_dma(uap); + + pl011_dma_rx_chars(uap, pending, lastbuf, false); +- spin_unlock_irq(&uap->port.lock); ++ uart_port_unlock_irq(&uap->port); + /* + * Do this check after we picked the DMA chars so we don't + * get some IRQ immediately from RX. +@@ -1086,11 +1086,11 @@ static void pl011_dma_rx_poll(struct tim + if (jiffies_to_msecs(jiffies - dmarx->last_jiffies) + > uap->dmarx.poll_timeout) { + +- spin_lock_irqsave(&uap->port.lock, flags); ++ uart_port_lock_irqsave(&uap->port, &flags); + pl011_dma_rx_stop(uap); + uap->im |= UART011_RXIM; + pl011_write(uap->im, uap, REG_IMSC); +- spin_unlock_irqrestore(&uap->port.lock, flags); ++ uart_port_unlock_irqrestore(&uap->port, flags); + + uap->dmarx.running = false; + dmaengine_terminate_all(rxchan); +@@ -1186,10 +1186,10 @@ static void pl011_dma_shutdown(struct ua + while (pl011_read(uap, REG_FR) & uap->vendor->fr_busy) + cpu_relax(); + +- spin_lock_irq(&uap->port.lock); ++ uart_port_lock_irq(&uap->port); + uap->dmacr &= ~(UART011_DMAONERR | UART011_RXDMAE | UART011_TXDMAE); + pl011_write(uap->dmacr, uap, REG_DMACR); +- spin_unlock_irq(&uap->port.lock); ++ uart_port_unlock_irq(&uap->port); + + if (uap->using_tx_dma) { + /* In theory, this should already be done by pl011_dma_flush_buffer */ +@@ -1370,9 +1370,9 @@ static void pl011_throttle_rx(struct uar + { + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + pl011_stop_rx(port); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void pl011_enable_ms(struct uart_port *port) +@@ -1390,7 +1390,7 @@ static void pl011_rx_chars(struct uart_a + { + pl011_fifo_to_tty(uap); + +- spin_unlock(&uap->port.lock); ++ uart_port_unlock(&uap->port); + tty_flip_buffer_push(&uap->port.state->port); + /* + * If we were temporarily out of DMA mode for a while, +@@ -1415,7 +1415,7 @@ static void pl011_rx_chars(struct uart_a + #endif + } + } +- spin_lock(&uap->port.lock); ++ uart_port_lock(&uap->port); + } + + static bool pl011_tx_char(struct uart_amba_port *uap, unsigned char c, +@@ -1551,7 +1551,7 @@ static irqreturn_t pl011_int(int irq, vo + unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT; + int handled = 0; + +- spin_lock_irqsave(&uap->port.lock, flags); ++ uart_port_lock_irqsave(&uap->port, &flags); + status = pl011_read(uap, REG_RIS) & uap->im; + if (status) { + do { +@@ -1581,7 +1581,7 @@ static irqreturn_t pl011_int(int irq, vo + handled = 1; + } + +- spin_unlock_irqrestore(&uap->port.lock, flags); ++ uart_port_unlock_irqrestore(&uap->port, flags); + + return IRQ_RETVAL(handled); + } +@@ -1653,14 +1653,14 @@ static void pl011_break_ctl(struct uart_ + unsigned long flags; + unsigned int lcr_h; + +- spin_lock_irqsave(&uap->port.lock, flags); ++ uart_port_lock_irqsave(&uap->port, &flags); + lcr_h = pl011_read(uap, REG_LCRH_TX); + if (break_state == -1) + lcr_h |= UART01x_LCRH_BRK; + else + lcr_h &= ~UART01x_LCRH_BRK; + pl011_write(lcr_h, uap, REG_LCRH_TX); +- spin_unlock_irqrestore(&uap->port.lock, flags); ++ uart_port_unlock_irqrestore(&uap->port, flags); + } + + #ifdef CONFIG_CONSOLE_POLL +@@ -1799,7 +1799,7 @@ static void pl011_enable_interrupts(stru + unsigned long flags; + unsigned int i; + +- spin_lock_irqsave(&uap->port.lock, flags); ++ uart_port_lock_irqsave(&uap->port, &flags); + + /* Clear out any spuriously appearing RX interrupts */ + pl011_write(UART011_RTIS | UART011_RXIS, uap, REG_ICR); +@@ -1821,7 +1821,7 @@ static void pl011_enable_interrupts(stru + if (!pl011_dma_rx_running(uap)) + uap->im |= UART011_RXIM; + pl011_write(uap->im, uap, REG_IMSC); +- spin_unlock_irqrestore(&uap->port.lock, flags); ++ uart_port_unlock_irqrestore(&uap->port, flags); + } + + static void pl011_unthrottle_rx(struct uart_port *port) +@@ -1829,7 +1829,7 @@ static void pl011_unthrottle_rx(struct u + struct uart_amba_port *uap = container_of(port, struct uart_amba_port, port); + unsigned long flags; + +- spin_lock_irqsave(&uap->port.lock, flags); ++ uart_port_lock_irqsave(&uap->port, &flags); + + uap->im = UART011_RTIM; + if (!pl011_dma_rx_running(uap)) +@@ -1837,7 +1837,7 @@ static void pl011_unthrottle_rx(struct u + + pl011_write(uap->im, uap, REG_IMSC); + +- spin_unlock_irqrestore(&uap->port.lock, flags); ++ uart_port_unlock_irqrestore(&uap->port, flags); + } + + static int pl011_startup(struct uart_port *port) +@@ -1857,7 +1857,7 @@ static int pl011_startup(struct uart_por + + pl011_write(uap->vendor->ifls, uap, REG_IFLS); + +- spin_lock_irq(&uap->port.lock); ++ uart_port_lock_irq(&uap->port); + + cr = pl011_read(uap, REG_CR); + cr &= UART011_CR_RTS | UART011_CR_DTR; +@@ -1868,7 +1868,7 @@ static int pl011_startup(struct uart_por + + pl011_write(cr, uap, REG_CR); + +- spin_unlock_irq(&uap->port.lock); ++ uart_port_unlock_irq(&uap->port); + + /* + * initialise the old status of the modem signals +@@ -1929,12 +1929,12 @@ static void pl011_disable_uart(struct ua + unsigned int cr; + + uap->port.status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS); +- spin_lock_irq(&uap->port.lock); ++ uart_port_lock_irq(&uap->port); + cr = pl011_read(uap, REG_CR); + cr &= UART011_CR_RTS | UART011_CR_DTR; + cr |= UART01x_CR_UARTEN | UART011_CR_TXE; + pl011_write(cr, uap, REG_CR); +- spin_unlock_irq(&uap->port.lock); ++ uart_port_unlock_irq(&uap->port); + + /* + * disable break condition and fifos +@@ -1946,14 +1946,14 @@ static void pl011_disable_uart(struct ua + + static void pl011_disable_interrupts(struct uart_amba_port *uap) + { +- spin_lock_irq(&uap->port.lock); ++ uart_port_lock_irq(&uap->port); + + /* mask all interrupts and clear all pending ones */ + uap->im = 0; + pl011_write(uap->im, uap, REG_IMSC); + pl011_write(0xffff, uap, REG_ICR); + +- spin_unlock_irq(&uap->port.lock); ++ uart_port_unlock_irq(&uap->port); + } + + static void pl011_shutdown(struct uart_port *port) +@@ -2098,7 +2098,7 @@ pl011_set_termios(struct uart_port *port + + bits = tty_get_frame_size(termios->c_cflag); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* + * Update the per-port timeout. +@@ -2172,7 +2172,7 @@ pl011_set_termios(struct uart_port *port + old_cr |= UART011_CR_RXE; + pl011_write(old_cr, uap, REG_CR); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void +@@ -2190,10 +2190,10 @@ sbsa_uart_set_termios(struct uart_port * + termios->c_cflag &= ~(CMSPAR | CRTSCTS); + termios->c_cflag |= CS8 | CLOCAL; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + uart_update_timeout(port, CS8, uap->fixed_baud); + pl011_setup_status_masks(port, termios); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *pl011_type(struct uart_port *port) +@@ -2332,9 +2332,9 @@ pl011_console_write(struct console *co, + if (uap->port.sysrq) + locked = 0; + else if (oops_in_progress) +- locked = spin_trylock(&uap->port.lock); ++ locked = uart_port_trylock(&uap->port); + else +- spin_lock(&uap->port.lock); ++ uart_port_lock(&uap->port); + + /* + * First save the CR then disable the interrupts +@@ -2360,7 +2360,7 @@ pl011_console_write(struct console *co, + pl011_write(old_cr, uap, REG_CR); + + if (locked) +- spin_unlock(&uap->port.lock); ++ uart_port_unlock(&uap->port); + local_irq_restore(flags); + + clk_disable(uap->clk); diff --git a/debian/patches-rt/0018-serial-apb-Use-port-lock-wrappers.patch b/debian/patches-rt/0018-serial-apb-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..4dcf54a89 --- /dev/null +++ b/debian/patches-rt/0018-serial-apb-Use-port-lock-wrappers.patch @@ -0,0 +1,76 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:35 +0206 +Subject: [PATCH 018/134] serial: apb: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-19-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/apbuart.c | 8 ++++---- + 1 file changed, 4 insertions(+), 4 deletions(-) + +--- a/drivers/tty/serial/apbuart.c ++++ b/drivers/tty/serial/apbuart.c +@@ -133,7 +133,7 @@ static irqreturn_t apbuart_int(int irq, + struct uart_port *port = dev_id; + unsigned int status; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + status = UART_GET_STATUS(port); + if (status & UART_STATUS_DR) +@@ -141,7 +141,7 @@ static irqreturn_t apbuart_int(int irq, + if (status & UART_STATUS_THE) + apbuart_tx_chars(port); + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return IRQ_HANDLED; + } +@@ -228,7 +228,7 @@ static void apbuart_set_termios(struct u + if (termios->c_cflag & CRTSCTS) + cr |= UART_CTRL_FL; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Update the per-port timeout. */ + uart_update_timeout(port, termios->c_cflag, baud); +@@ -251,7 +251,7 @@ static void apbuart_set_termios(struct u + UART_PUT_SCAL(port, quot); + UART_PUT_CTRL(port, cr); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *apbuart_type(struct uart_port *port) diff --git a/debian/patches-rt/0019-serial-ar933x-Use-port-lock-wrappers.patch b/debian/patches-rt/0019-serial-ar933x-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..61a5d3b1a --- /dev/null +++ b/debian/patches-rt/0019-serial-ar933x-Use-port-lock-wrappers.patch @@ -0,0 +1,144 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:36 +0206 +Subject: [PATCH 019/134] serial: ar933x: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-20-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/ar933x_uart.c | 26 +++++++++++++------------- + 1 file changed, 13 insertions(+), 13 deletions(-) + +--- a/drivers/tty/serial/ar933x_uart.c ++++ b/drivers/tty/serial/ar933x_uart.c +@@ -133,9 +133,9 @@ static unsigned int ar933x_uart_tx_empty + unsigned long flags; + unsigned int rdata; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + return (rdata & AR933X_UART_DATA_TX_CSR) ? 0 : TIOCSER_TEMT; + } +@@ -220,14 +220,14 @@ static void ar933x_uart_break_ctl(struct + container_of(port, struct ar933x_uart_port, port); + unsigned long flags; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + if (break_state == -1) + ar933x_uart_rmw_set(up, AR933X_UART_CS_REG, + AR933X_UART_CS_TX_BREAK); + else + ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG, + AR933X_UART_CS_TX_BREAK); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + /* +@@ -318,7 +318,7 @@ static void ar933x_uart_set_termios(stru + * Ok, we're now changing the port state. Do it with + * interrupts disabled. + */ +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + /* disable the UART */ + ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG, +@@ -352,7 +352,7 @@ static void ar933x_uart_set_termios(stru + AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S, + AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S); + +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + if (tty_termios_baud_rate(new)) + tty_termios_encode_baud_rate(new, baud, baud); +@@ -450,7 +450,7 @@ static irqreturn_t ar933x_uart_interrupt + if ((status & AR933X_UART_CS_HOST_INT) == 0) + return IRQ_NONE; + +- spin_lock(&up->port.lock); ++ uart_port_lock(&up->port); + + status = ar933x_uart_read(up, AR933X_UART_INT_REG); + status &= ar933x_uart_read(up, AR933X_UART_INT_EN_REG); +@@ -468,7 +468,7 @@ static irqreturn_t ar933x_uart_interrupt + ar933x_uart_tx_chars(up); + } + +- spin_unlock(&up->port.lock); ++ uart_port_unlock(&up->port); + + return IRQ_HANDLED; + } +@@ -485,7 +485,7 @@ static int ar933x_uart_startup(struct ua + if (ret) + return ret; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + /* Enable HOST interrupts */ + ar933x_uart_rmw_set(up, AR933X_UART_CS_REG, +@@ -498,7 +498,7 @@ static int ar933x_uart_startup(struct ua + /* Enable RX interrupts */ + ar933x_uart_start_rx_interrupt(up); + +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + return 0; + } +@@ -632,9 +632,9 @@ static void ar933x_uart_console_write(st + if (up->port.sysrq) + locked = 0; + else if (oops_in_progress) +- locked = spin_trylock(&up->port.lock); ++ locked = uart_port_trylock(&up->port); + else +- spin_lock(&up->port.lock); ++ uart_port_lock(&up->port); + + /* + * First save the IER then disable the interrupts +@@ -654,7 +654,7 @@ static void ar933x_uart_console_write(st + ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_ALLINTS); + + if (locked) +- spin_unlock(&up->port.lock); ++ uart_port_unlock(&up->port); + + local_irq_restore(flags); + } diff --git a/debian/patches-rt/0020-serial-arc_uart-Use-port-lock-wrappers.patch b/debian/patches-rt/0020-serial-arc_uart-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..bc7be2c4d --- /dev/null +++ b/debian/patches-rt/0020-serial-arc_uart-Use-port-lock-wrappers.patch @@ -0,0 +1,97 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:37 +0206 +Subject: [PATCH 020/134] serial: arc_uart: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-21-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/arc_uart.c | 16 ++++++++-------- + 1 file changed, 8 insertions(+), 8 deletions(-) + +--- a/drivers/tty/serial/arc_uart.c ++++ b/drivers/tty/serial/arc_uart.c +@@ -279,9 +279,9 @@ static irqreturn_t arc_serial_isr(int ir + if (status & RXIENB) { + + /* already in ISR, no need of xx_irqsave */ +- spin_lock(&port->lock); ++ uart_port_lock(port); + arc_serial_rx_chars(port, status); +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + } + + if ((status & TXIENB) && (status & TXEMPTY)) { +@@ -291,12 +291,12 @@ static irqreturn_t arc_serial_isr(int ir + */ + UART_TX_IRQ_DISABLE(port); + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + if (!uart_tx_stopped(port)) + arc_serial_tx_chars(port); + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + } + + return IRQ_HANDLED; +@@ -366,7 +366,7 @@ arc_serial_set_termios(struct uart_port + uartl = hw_val & 0xFF; + uarth = (hw_val >> 8) & 0xFF; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + UART_ALL_IRQ_DISABLE(port); + +@@ -391,7 +391,7 @@ arc_serial_set_termios(struct uart_port + + uart_update_timeout(port, new->c_cflag, baud); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *arc_serial_type(struct uart_port *port) +@@ -521,9 +521,9 @@ static void arc_serial_console_write(str + struct uart_port *port = &arc_uart_ports[co->index].port; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + uart_console_write(port, s, count, arc_serial_console_putchar); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static struct console arc_console = { diff --git a/debian/patches-rt/0021-serial-atmel-Use-port-lock-wrappers.patch b/debian/patches-rt/0021-serial-atmel-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..ab70954a1 --- /dev/null +++ b/debian/patches-rt/0021-serial-atmel-Use-port-lock-wrappers.patch @@ -0,0 +1,119 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:38 +0206 +Subject: [PATCH 021/134] serial: atmel: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-22-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/atmel_serial.c | 24 ++++++++++++------------ + 1 file changed, 12 insertions(+), 12 deletions(-) + +--- a/drivers/tty/serial/atmel_serial.c ++++ b/drivers/tty/serial/atmel_serial.c +@@ -861,7 +861,7 @@ static void atmel_complete_tx_dma(void * + struct dma_chan *chan = atmel_port->chan_tx; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + if (chan) + dmaengine_terminate_all(chan); +@@ -893,7 +893,7 @@ static void atmel_complete_tx_dma(void * + atmel_port->tx_done_mask); + } + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void atmel_release_tx_dma(struct uart_port *port) +@@ -1711,9 +1711,9 @@ static void atmel_tasklet_rx_func(struct + struct uart_port *port = &atmel_port->uart; + + /* The interrupt handler does not take the lock */ +- spin_lock(&port->lock); ++ uart_port_lock(port); + atmel_port->schedule_rx(port); +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + } + + static void atmel_tasklet_tx_func(struct tasklet_struct *t) +@@ -1723,9 +1723,9 @@ static void atmel_tasklet_tx_func(struct + struct uart_port *port = &atmel_port->uart; + + /* The interrupt handler does not take the lock */ +- spin_lock(&port->lock); ++ uart_port_lock(port); + atmel_port->schedule_tx(port); +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + } + + static void atmel_init_property(struct atmel_uart_port *atmel_port, +@@ -2175,7 +2175,7 @@ static void atmel_set_termios(struct uar + } else + mode |= ATMEL_US_PAR_NONE; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + port->read_status_mask = ATMEL_US_OVRE; + if (termios->c_iflag & INPCK) +@@ -2377,22 +2377,22 @@ static void atmel_set_termios(struct uar + else + atmel_disable_ms(port); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void atmel_set_ldisc(struct uart_port *port, struct ktermios *termios) + { + if (termios->c_line == N_PPS) { + port->flags |= UPF_HARDPPS_CD; +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + atmel_enable_ms(port); +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + } else { + port->flags &= ~UPF_HARDPPS_CD; + if (!UART_ENABLE_MS(port, termios->c_cflag)) { +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + atmel_disable_ms(port); +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + } + } + } diff --git a/debian/patches-rt/0022-serial-bcm63xx-uart-Use-port-lock-wrappers.patch b/debian/patches-rt/0022-serial-bcm63xx-uart-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..90efec408 --- /dev/null +++ b/debian/patches-rt/0022-serial-bcm63xx-uart-Use-port-lock-wrappers.patch @@ -0,0 +1,128 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:39 +0206 +Subject: [PATCH 022/134] serial: bcm63xx-uart: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Reviewed-by: Florian Fainelli +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-23-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/bcm63xx_uart.c | 22 +++++++++++----------- + 1 file changed, 11 insertions(+), 11 deletions(-) + +--- a/drivers/tty/serial/bcm63xx_uart.c ++++ b/drivers/tty/serial/bcm63xx_uart.c +@@ -201,7 +201,7 @@ static void bcm_uart_break_ctl(struct ua + unsigned long flags; + unsigned int val; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + val = bcm_uart_readl(port, UART_CTL_REG); + if (ctl) +@@ -210,7 +210,7 @@ static void bcm_uart_break_ctl(struct ua + val &= ~UART_CTL_XMITBRK_MASK; + bcm_uart_writel(port, val, UART_CTL_REG); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /* +@@ -332,7 +332,7 @@ static irqreturn_t bcm_uart_interrupt(in + unsigned int irqstat; + + port = dev_id; +- spin_lock(&port->lock); ++ uart_port_lock(port); + + irqstat = bcm_uart_readl(port, UART_IR_REG); + if (irqstat & UART_RX_INT_STAT) +@@ -353,7 +353,7 @@ static irqreturn_t bcm_uart_interrupt(in + estat & UART_EXTINP_DCD_MASK); + } + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + return IRQ_HANDLED; + } + +@@ -451,9 +451,9 @@ static void bcm_uart_shutdown(struct uar + { + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + bcm_uart_writel(port, 0, UART_IR_REG); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + bcm_uart_disable(port); + bcm_uart_flush(port); +@@ -470,7 +470,7 @@ static void bcm_uart_set_termios(struct + unsigned long flags; + int tries; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Drain the hot tub fully before we power it off for the winter. */ + for (tries = 3; !bcm_uart_tx_empty(port) && tries; tries--) +@@ -546,7 +546,7 @@ static void bcm_uart_set_termios(struct + + uart_update_timeout(port, new->c_cflag, baud); + bcm_uart_enable(port); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /* +@@ -712,9 +712,9 @@ static void bcm_console_write(struct con + /* bcm_uart_interrupt() already took the lock */ + locked = 0; + } else if (oops_in_progress) { +- locked = spin_trylock(&port->lock); ++ locked = uart_port_trylock(port); + } else { +- spin_lock(&port->lock); ++ uart_port_lock(port); + locked = 1; + } + +@@ -725,7 +725,7 @@ static void bcm_console_write(struct con + wait_for_xmitr(port); + + if (locked) +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + local_irq_restore(flags); + } + diff --git a/debian/patches-rt/0023-serial-cpm_uart-Use-port-lock-wrappers.patch b/debian/patches-rt/0023-serial-cpm_uart-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..c3400eac9 --- /dev/null +++ b/debian/patches-rt/0023-serial-cpm_uart-Use-port-lock-wrappers.patch @@ -0,0 +1,70 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:40 +0206 +Subject: [PATCH 023/134] serial: cpm_uart: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-24-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/cpm_uart.c | 8 ++++---- + 1 file changed, 4 insertions(+), 4 deletions(-) + +--- a/drivers/tty/serial/cpm_uart.c ++++ b/drivers/tty/serial/cpm_uart.c +@@ -569,7 +569,7 @@ static void cpm_uart_set_termios(struct + if ((termios->c_cflag & CREAD) == 0) + port->read_status_mask &= ~BD_SC_EMPTY; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + if (IS_SMC(pinfo)) { + unsigned int bits = tty_get_frame_size(termios->c_cflag); +@@ -609,7 +609,7 @@ static void cpm_uart_set_termios(struct + clk_set_rate(pinfo->clk, baud); + else + cpm_setbrg(pinfo->brg - 1, baud); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *cpm_uart_type(struct uart_port *port) +@@ -1386,9 +1386,9 @@ static void cpm_uart_console_write(struc + cpm_uart_early_write(pinfo, s, count, true); + local_irq_restore(flags); + } else { +- spin_lock_irqsave(&pinfo->port.lock, flags); ++ uart_port_lock_irqsave(&pinfo->port, &flags); + cpm_uart_early_write(pinfo, s, count, true); +- spin_unlock_irqrestore(&pinfo->port.lock, flags); ++ uart_port_unlock_irqrestore(&pinfo->port, flags); + } + } + diff --git a/debian/patches-rt/0024-serial-digicolor-Use-port-lock-wrappers.patch b/debian/patches-rt/0024-serial-digicolor-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..2a3aa5c9a --- /dev/null +++ b/debian/patches-rt/0024-serial-digicolor-Use-port-lock-wrappers.patch @@ -0,0 +1,113 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:41 +0206 +Subject: [PATCH 024/134] serial: digicolor: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Acked-by: Baruch Siach +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-25-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/digicolor-usart.c | 18 +++++++++--------- + 1 file changed, 9 insertions(+), 9 deletions(-) + +--- a/drivers/tty/serial/digicolor-usart.c ++++ b/drivers/tty/serial/digicolor-usart.c +@@ -133,7 +133,7 @@ static void digicolor_uart_rx(struct uar + { + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + while (1) { + u8 status, ch, ch_flag; +@@ -172,7 +172,7 @@ static void digicolor_uart_rx(struct uar + ch_flag); + } + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + tty_flip_buffer_push(&port->state->port); + } +@@ -185,7 +185,7 @@ static void digicolor_uart_tx(struct uar + if (digicolor_uart_tx_full(port)) + return; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + if (port->x_char) { + writeb_relaxed(port->x_char, port->membase + UA_EMI_REC); +@@ -211,7 +211,7 @@ static void digicolor_uart_tx(struct uar + uart_write_wakeup(port); + + out: +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static irqreturn_t digicolor_uart_int(int irq, void *dev_id) +@@ -333,7 +333,7 @@ static void digicolor_uart_set_termios(s + port->ignore_status_mask |= UA_STATUS_OVERRUN_ERR + | UA_STATUS_PARITY_ERR | UA_STATUS_FRAME_ERR; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + uart_update_timeout(port, termios->c_cflag, baud); + +@@ -341,7 +341,7 @@ static void digicolor_uart_set_termios(s + writeb_relaxed(divisor & 0xff, port->membase + UA_HBAUD_LO); + writeb_relaxed(divisor >> 8, port->membase + UA_HBAUD_HI); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *digicolor_uart_type(struct uart_port *port) +@@ -398,14 +398,14 @@ static void digicolor_uart_console_write + int locked = 1; + + if (oops_in_progress) +- locked = spin_trylock_irqsave(&port->lock, flags); ++ locked = uart_port_trylock_irqsave(port, &flags); + else +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + uart_console_write(port, c, n, digicolor_uart_console_putchar); + + if (locked) +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + /* Wait for transmitter to become empty */ + do { diff --git a/debian/patches-rt/0025-serial-dz-Use-port-lock-wrappers.patch b/debian/patches-rt/0025-serial-dz-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..7b3f11604 --- /dev/null +++ b/debian/patches-rt/0025-serial-dz-Use-port-lock-wrappers.patch @@ -0,0 +1,161 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:42 +0206 +Subject: [PATCH 025/134] serial: dz: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-26-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/dz.c | 32 ++++++++++++++++---------------- + 1 file changed, 16 insertions(+), 16 deletions(-) + +--- a/drivers/tty/serial/dz.c ++++ b/drivers/tty/serial/dz.c +@@ -268,9 +268,9 @@ static inline void dz_transmit_chars(str + } + /* If nothing to do or stopped or hardware stopped. */ + if (uart_circ_empty(xmit) || uart_tx_stopped(&dport->port)) { +- spin_lock(&dport->port.lock); ++ uart_port_lock(&dport->port); + dz_stop_tx(&dport->port); +- spin_unlock(&dport->port.lock); ++ uart_port_unlock(&dport->port); + return; + } + +@@ -287,9 +287,9 @@ static inline void dz_transmit_chars(str + + /* Are we are done. */ + if (uart_circ_empty(xmit)) { +- spin_lock(&dport->port.lock); ++ uart_port_lock(&dport->port); + dz_stop_tx(&dport->port); +- spin_unlock(&dport->port.lock); ++ uart_port_unlock(&dport->port); + } + } + +@@ -415,14 +415,14 @@ static int dz_startup(struct uart_port * + return ret; + } + +- spin_lock_irqsave(&dport->port.lock, flags); ++ uart_port_lock_irqsave(&dport->port, &flags); + + /* Enable interrupts. */ + tmp = dz_in(dport, DZ_CSR); + tmp |= DZ_RIE | DZ_TIE; + dz_out(dport, DZ_CSR, tmp); + +- spin_unlock_irqrestore(&dport->port.lock, flags); ++ uart_port_unlock_irqrestore(&dport->port, flags); + + return 0; + } +@@ -443,9 +443,9 @@ static void dz_shutdown(struct uart_port + int irq_guard; + u16 tmp; + +- spin_lock_irqsave(&dport->port.lock, flags); ++ uart_port_lock_irqsave(&dport->port, &flags); + dz_stop_tx(&dport->port); +- spin_unlock_irqrestore(&dport->port.lock, flags); ++ uart_port_unlock_irqrestore(&dport->port, flags); + + irq_guard = atomic_add_return(-1, &mux->irq_guard); + if (!irq_guard) { +@@ -491,14 +491,14 @@ static void dz_break_ctl(struct uart_por + unsigned long flags; + unsigned short tmp, mask = 1 << dport->port.line; + +- spin_lock_irqsave(&uport->lock, flags); ++ uart_port_lock_irqsave(uport, &flags); + tmp = dz_in(dport, DZ_TCR); + if (break_state) + tmp |= mask; + else + tmp &= ~mask; + dz_out(dport, DZ_TCR, tmp); +- spin_unlock_irqrestore(&uport->lock, flags); ++ uart_port_unlock_irqrestore(uport, flags); + } + + static int dz_encode_baud_rate(unsigned int baud) +@@ -608,7 +608,7 @@ static void dz_set_termios(struct uart_p + if (termios->c_cflag & CREAD) + cflag |= DZ_RXENAB; + +- spin_lock_irqsave(&dport->port.lock, flags); ++ uart_port_lock_irqsave(&dport->port, &flags); + + uart_update_timeout(uport, termios->c_cflag, baud); + +@@ -631,7 +631,7 @@ static void dz_set_termios(struct uart_p + if (termios->c_iflag & IGNBRK) + dport->port.ignore_status_mask |= DZ_BREAK; + +- spin_unlock_irqrestore(&dport->port.lock, flags); ++ uart_port_unlock_irqrestore(&dport->port, flags); + } + + /* +@@ -645,12 +645,12 @@ static void dz_pm(struct uart_port *upor + struct dz_port *dport = to_dport(uport); + unsigned long flags; + +- spin_lock_irqsave(&dport->port.lock, flags); ++ uart_port_lock_irqsave(&dport->port, &flags); + if (state < 3) + dz_start_tx(&dport->port); + else + dz_stop_tx(&dport->port); +- spin_unlock_irqrestore(&dport->port.lock, flags); ++ uart_port_unlock_irqrestore(&dport->port, flags); + } + + +@@ -811,7 +811,7 @@ static void dz_console_putchar(struct ua + unsigned short csr, tcr, trdy, mask; + int loops = 10000; + +- spin_lock_irqsave(&dport->port.lock, flags); ++ uart_port_lock_irqsave(&dport->port, &flags); + csr = dz_in(dport, DZ_CSR); + dz_out(dport, DZ_CSR, csr & ~DZ_TIE); + tcr = dz_in(dport, DZ_TCR); +@@ -819,7 +819,7 @@ static void dz_console_putchar(struct ua + mask = tcr; + dz_out(dport, DZ_TCR, mask); + iob(); +- spin_unlock_irqrestore(&dport->port.lock, flags); ++ uart_port_unlock_irqrestore(&dport->port, flags); + + do { + trdy = dz_in(dport, DZ_CSR); diff --git a/debian/patches-rt/0026-serial-linflexuart-Use-port-lock-wrappers.patch b/debian/patches-rt/0026-serial-linflexuart-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..e2a3628ae --- /dev/null +++ b/debian/patches-rt/0026-serial-linflexuart-Use-port-lock-wrappers.patch @@ -0,0 +1,143 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:43 +0206 +Subject: [PATCH 026/134] serial: linflexuart: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-27-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/fsl_linflexuart.c | 26 +++++++++++++------------- + 1 file changed, 13 insertions(+), 13 deletions(-) + +--- a/drivers/tty/serial/fsl_linflexuart.c ++++ b/drivers/tty/serial/fsl_linflexuart.c +@@ -203,7 +203,7 @@ static irqreturn_t linflex_txint(int irq + struct circ_buf *xmit = &sport->state->xmit; + unsigned long flags; + +- spin_lock_irqsave(&sport->lock, flags); ++ uart_port_lock_irqsave(sport, &flags); + + if (sport->x_char) { + linflex_put_char(sport, sport->x_char); +@@ -217,7 +217,7 @@ static irqreturn_t linflex_txint(int irq + + linflex_transmit_buffer(sport); + out: +- spin_unlock_irqrestore(&sport->lock, flags); ++ uart_port_unlock_irqrestore(sport, flags); + return IRQ_HANDLED; + } + +@@ -230,7 +230,7 @@ static irqreturn_t linflex_rxint(int irq + unsigned char rx; + bool brk; + +- spin_lock_irqsave(&sport->lock, flags); ++ uart_port_lock_irqsave(sport, &flags); + + status = readl(sport->membase + UARTSR); + while (status & LINFLEXD_UARTSR_RMB) { +@@ -266,7 +266,7 @@ static irqreturn_t linflex_rxint(int irq + } + } + +- spin_unlock_irqrestore(&sport->lock, flags); ++ uart_port_unlock_irqrestore(sport, flags); + + tty_flip_buffer_push(port); + +@@ -369,11 +369,11 @@ static int linflex_startup(struct uart_p + int ret = 0; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + linflex_setup_watermark(port); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + ret = devm_request_irq(port->dev, port->irq, linflex_int, 0, + DRIVER_NAME, port); +@@ -386,14 +386,14 @@ static void linflex_shutdown(struct uart + unsigned long ier; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* disable interrupts */ + ier = readl(port->membase + LINIER); + ier &= ~(LINFLEXD_LINIER_DRIE | LINFLEXD_LINIER_DTIE); + writel(ier, port->membase + LINIER); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + devm_free_irq(port->dev, port->irq, port); + } +@@ -474,7 +474,7 @@ linflex_set_termios(struct uart_port *po + cr &= ~LINFLEXD_UARTCR_PCE; + } + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + port->read_status_mask = 0; + +@@ -507,7 +507,7 @@ linflex_set_termios(struct uart_port *po + + writel(cr1, port->membase + LINCR1); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *linflex_type(struct uart_port *port) +@@ -646,14 +646,14 @@ linflex_console_write(struct console *co + if (sport->sysrq) + locked = 0; + else if (oops_in_progress) +- locked = spin_trylock_irqsave(&sport->lock, flags); ++ locked = uart_port_trylock_irqsave(sport, &flags); + else +- spin_lock_irqsave(&sport->lock, flags); ++ uart_port_lock_irqsave(sport, &flags); + + linflex_string_write(sport, s, count); + + if (locked) +- spin_unlock_irqrestore(&sport->lock, flags); ++ uart_port_unlock_irqrestore(sport, flags); + } + + /* diff --git a/debian/patches-rt/0027-serial-fsl_lpuart-Use-port-lock-wrappers.patch b/debian/patches-rt/0027-serial-fsl_lpuart-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..f1475a5ff --- /dev/null +++ b/debian/patches-rt/0027-serial-fsl_lpuart-Use-port-lock-wrappers.patch @@ -0,0 +1,389 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:44 +0206 +Subject: [PATCH 027/134] serial: fsl_lpuart: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-28-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/fsl_lpuart.c | 88 ++++++++++++++++++++-------------------- + 1 file changed, 44 insertions(+), 44 deletions(-) + +--- a/drivers/tty/serial/fsl_lpuart.c ++++ b/drivers/tty/serial/fsl_lpuart.c +@@ -532,9 +532,9 @@ static void lpuart_dma_tx_complete(void + struct dma_chan *chan = sport->dma_tx_chan; + unsigned long flags; + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + if (!sport->dma_tx_in_progress) { +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + return; + } + +@@ -543,7 +543,7 @@ static void lpuart_dma_tx_complete(void + + uart_xmit_advance(&sport->port, sport->dma_tx_bytes); + sport->dma_tx_in_progress = false; +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + uart_write_wakeup(&sport->port); +@@ -553,12 +553,12 @@ static void lpuart_dma_tx_complete(void + return; + } + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + + if (!lpuart_stopped_or_empty(&sport->port)) + lpuart_dma_tx(sport); + +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + } + + static dma_addr_t lpuart_dma_datareg_addr(struct lpuart_port *sport) +@@ -651,7 +651,7 @@ static int lpuart_poll_init(struct uart_ + + sport->port.fifosize = 0; + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + /* Disable Rx & Tx */ + writeb(0, sport->port.membase + UARTCR2); + +@@ -675,7 +675,7 @@ static int lpuart_poll_init(struct uart_ + + /* Enable Rx and Tx */ + writeb(UARTCR2_RE | UARTCR2_TE, sport->port.membase + UARTCR2); +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + + return 0; + } +@@ -703,7 +703,7 @@ static int lpuart32_poll_init(struct uar + + sport->port.fifosize = 0; + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + + /* Disable Rx & Tx */ + lpuart32_write(&sport->port, 0, UARTCTRL); +@@ -724,7 +724,7 @@ static int lpuart32_poll_init(struct uar + + /* Enable Rx and Tx */ + lpuart32_write(&sport->port, UARTCTRL_RE | UARTCTRL_TE, UARTCTRL); +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + + return 0; + } +@@ -879,9 +879,9 @@ static unsigned int lpuart32_tx_empty(st + + static void lpuart_txint(struct lpuart_port *sport) + { +- spin_lock(&sport->port.lock); ++ uart_port_lock(&sport->port); + lpuart_transmit_buffer(sport); +- spin_unlock(&sport->port.lock); ++ uart_port_unlock(&sport->port); + } + + static void lpuart_rxint(struct lpuart_port *sport) +@@ -890,7 +890,7 @@ static void lpuart_rxint(struct lpuart_p + struct tty_port *port = &sport->port.state->port; + unsigned char rx, sr; + +- spin_lock(&sport->port.lock); ++ uart_port_lock(&sport->port); + + while (!(readb(sport->port.membase + UARTSFIFO) & UARTSFIFO_RXEMPT)) { + flg = TTY_NORMAL; +@@ -956,9 +956,9 @@ static void lpuart_rxint(struct lpuart_p + + static void lpuart32_txint(struct lpuart_port *sport) + { +- spin_lock(&sport->port.lock); ++ uart_port_lock(&sport->port); + lpuart32_transmit_buffer(sport); +- spin_unlock(&sport->port.lock); ++ uart_port_unlock(&sport->port); + } + + static void lpuart32_rxint(struct lpuart_port *sport) +@@ -968,7 +968,7 @@ static void lpuart32_rxint(struct lpuart + unsigned long rx, sr; + bool is_break; + +- spin_lock(&sport->port.lock); ++ uart_port_lock(&sport->port); + + while (!(lpuart32_read(&sport->port, UARTFIFO) & UARTFIFO_RXEMPT)) { + flg = TTY_NORMAL; +@@ -1170,12 +1170,12 @@ static void lpuart_copy_rx_to_tty(struct + + async_tx_ack(sport->dma_rx_desc); + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + + dmastat = dmaengine_tx_status(chan, sport->dma_rx_cookie, &state); + if (dmastat == DMA_ERROR) { + dev_err(sport->port.dev, "Rx DMA transfer failed!\n"); +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + return; + } + +@@ -1244,7 +1244,7 @@ static void lpuart_copy_rx_to_tty(struct + dma_sync_sg_for_device(chan->device->dev, &sport->rx_sgl, 1, + DMA_FROM_DEVICE); + +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + + tty_flip_buffer_push(port); + if (!sport->dma_idle_int) +@@ -1335,9 +1335,9 @@ static void lpuart_timer_func(struct tim + mod_timer(&sport->lpuart_timer, + jiffies + sport->dma_rx_timeout); + +- if (spin_trylock_irqsave(&sport->port.lock, flags)) { ++ if (uart_port_trylock_irqsave(&sport->port, &flags)) { + sport->last_residue = state.residue; +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + } + } + +@@ -1802,14 +1802,14 @@ static void lpuart_hw_setup(struct lpuar + { + unsigned long flags; + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + + lpuart_setup_watermark_enable(sport); + + lpuart_rx_dma_startup(sport); + lpuart_tx_dma_startup(sport); + +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + } + + static int lpuart_startup(struct uart_port *port) +@@ -1859,7 +1859,7 @@ static void lpuart32_hw_setup(struct lpu + { + unsigned long flags; + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + + lpuart32_hw_disable(sport); + +@@ -1869,7 +1869,7 @@ static void lpuart32_hw_setup(struct lpu + lpuart32_setup_watermark_enable(sport); + lpuart32_configure(sport); + +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + } + + static int lpuart32_startup(struct uart_port *port) +@@ -1932,7 +1932,7 @@ static void lpuart_shutdown(struct uart_ + unsigned char temp; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* disable Rx/Tx and interrupts */ + temp = readb(port->membase + UARTCR2); +@@ -1940,7 +1940,7 @@ static void lpuart_shutdown(struct uart_ + UARTCR2_TIE | UARTCR2_TCIE | UARTCR2_RIE); + writeb(temp, port->membase + UARTCR2); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + lpuart_dma_shutdown(sport); + } +@@ -1952,7 +1952,7 @@ static void lpuart32_shutdown(struct uar + unsigned long temp; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* clear status */ + temp = lpuart32_read(&sport->port, UARTSTAT); +@@ -1969,7 +1969,7 @@ static void lpuart32_shutdown(struct uar + UARTCTRL_TIE | UARTCTRL_TCIE | UARTCTRL_RIE | UARTCTRL_SBK); + lpuart32_write(port, temp, UARTCTRL); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + lpuart_dma_shutdown(sport); + } +@@ -2069,7 +2069,7 @@ lpuart_set_termios(struct uart_port *por + if (old && sport->lpuart_dma_rx_use) + lpuart_dma_rx_free(&sport->port); + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + + sport->port.read_status_mask = 0; + if (termios->c_iflag & INPCK) +@@ -2124,7 +2124,7 @@ lpuart_set_termios(struct uart_port *por + sport->lpuart_dma_rx_use = false; + } + +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + } + + static void __lpuart32_serial_setbrg(struct uart_port *port, +@@ -2304,7 +2304,7 @@ lpuart32_set_termios(struct uart_port *p + if (old && sport->lpuart_dma_rx_use) + lpuart_dma_rx_free(&sport->port); + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + + sport->port.read_status_mask = 0; + if (termios->c_iflag & INPCK) +@@ -2359,7 +2359,7 @@ lpuart32_set_termios(struct uart_port *p + sport->lpuart_dma_rx_use = false; + } + +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + } + + static const char *lpuart_type(struct uart_port *port) +@@ -2477,9 +2477,9 @@ lpuart_console_write(struct console *co, + int locked = 1; + + if (oops_in_progress) +- locked = spin_trylock_irqsave(&sport->port.lock, flags); ++ locked = uart_port_trylock_irqsave(&sport->port, &flags); + else +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + + /* first save CR2 and then disable interrupts */ + cr2 = old_cr2 = readb(sport->port.membase + UARTCR2); +@@ -2495,7 +2495,7 @@ lpuart_console_write(struct console *co, + writeb(old_cr2, sport->port.membase + UARTCR2); + + if (locked) +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + } + + static void +@@ -2507,9 +2507,9 @@ lpuart32_console_write(struct console *c + int locked = 1; + + if (oops_in_progress) +- locked = spin_trylock_irqsave(&sport->port.lock, flags); ++ locked = uart_port_trylock_irqsave(&sport->port, &flags); + else +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + + /* first save CR2 and then disable interrupts */ + cr = old_cr = lpuart32_read(&sport->port, UARTCTRL); +@@ -2525,7 +2525,7 @@ lpuart32_console_write(struct console *c + lpuart32_write(&sport->port, old_cr, UARTCTRL); + + if (locked) +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + } + + /* +@@ -3089,7 +3089,7 @@ static int lpuart_suspend(struct device + uart_suspend_port(&lpuart_reg, &sport->port); + + if (lpuart_uport_is_active(sport)) { +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + if (lpuart_is_32(sport)) { + /* disable Rx/Tx and interrupts */ + temp = lpuart32_read(&sport->port, UARTCTRL); +@@ -3101,7 +3101,7 @@ static int lpuart_suspend(struct device + temp &= ~(UARTCR2_TE | UARTCR2_TIE | UARTCR2_TCIE); + writeb(temp, sport->port.membase + UARTCR2); + } +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + + if (sport->lpuart_dma_rx_use) { + /* +@@ -3114,7 +3114,7 @@ static int lpuart_suspend(struct device + lpuart_dma_rx_free(&sport->port); + + /* Disable Rx DMA to use UART port as wakeup source */ +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + if (lpuart_is_32(sport)) { + temp = lpuart32_read(&sport->port, UARTBAUD); + lpuart32_write(&sport->port, temp & ~UARTBAUD_RDMAE, +@@ -3123,11 +3123,11 @@ static int lpuart_suspend(struct device + writeb(readb(sport->port.membase + UARTCR5) & + ~UARTCR5_RDMAS, sport->port.membase + UARTCR5); + } +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + } + + if (sport->lpuart_dma_tx_use) { +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + if (lpuart_is_32(sport)) { + temp = lpuart32_read(&sport->port, UARTBAUD); + temp &= ~UARTBAUD_TDMAE; +@@ -3137,7 +3137,7 @@ static int lpuart_suspend(struct device + temp &= ~UARTCR5_TDMAS; + writeb(temp, sport->port.membase + UARTCR5); + } +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + sport->dma_tx_in_progress = false; + dmaengine_terminate_sync(sport->dma_tx_chan); + } diff --git a/debian/patches-rt/0028-serial-icom-Use-port-lock-wrappers.patch b/debian/patches-rt/0028-serial-icom-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..da765879c --- /dev/null +++ b/debian/patches-rt/0028-serial-icom-Use-port-lock-wrappers.patch @@ -0,0 +1,151 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:45 +0206 +Subject: [PATCH 028/134] serial: icom: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-29-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/icom.c | 26 +++++++++++++------------- + 1 file changed, 13 insertions(+), 13 deletions(-) + +--- a/drivers/tty/serial/icom.c ++++ b/drivers/tty/serial/icom.c +@@ -929,7 +929,7 @@ static inline void check_modem_status(st + char delta_status; + unsigned char status; + +- spin_lock(&icom_port->uart_port.lock); ++ uart_port_lock(&icom_port->uart_port); + + /*modem input register */ + status = readb(&icom_port->dram->isr); +@@ -951,7 +951,7 @@ static inline void check_modem_status(st + port.delta_msr_wait); + old_status = status; + } +- spin_unlock(&icom_port->uart_port.lock); ++ uart_port_unlock(&icom_port->uart_port); + } + + static void xmit_interrupt(u16 port_int_reg, struct icom_port *icom_port) +@@ -1093,7 +1093,7 @@ static void process_interrupt(u16 port_i + struct icom_port *icom_port) + { + +- spin_lock(&icom_port->uart_port.lock); ++ uart_port_lock(&icom_port->uart_port); + trace(icom_port, "INTERRUPT", port_int_reg); + + if (port_int_reg & (INT_XMIT_COMPLETED | INT_XMIT_DISABLED)) +@@ -1102,7 +1102,7 @@ static void process_interrupt(u16 port_i + if (port_int_reg & INT_RCV_COMPLETED) + recv_interrupt(port_int_reg, icom_port); + +- spin_unlock(&icom_port->uart_port.lock); ++ uart_port_unlock(&icom_port->uart_port); + } + + static irqreturn_t icom_interrupt(int irq, void *dev_id) +@@ -1186,14 +1186,14 @@ static unsigned int icom_tx_empty(struct + int ret; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + if (le16_to_cpu(icom_port->statStg->xmit[0].flags) & + SA_FLAGS_READY_TO_XMIT) + ret = TIOCSER_TEMT; + else + ret = 0; + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + return ret; + } + +@@ -1276,7 +1276,7 @@ static void icom_send_xchar(struct uart_ + + /* wait .1 sec to send char */ + for (index = 0; index < 10; index++) { +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + xdata = readb(&icom_port->dram->xchar); + if (xdata == 0x00) { + trace(icom_port, "QUICK_WRITE", 0); +@@ -1284,10 +1284,10 @@ static void icom_send_xchar(struct uart_ + + /* flush write operation */ + xdata = readb(&icom_port->dram->xchar); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + break; + } +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + msleep(10); + } + } +@@ -1307,7 +1307,7 @@ static void icom_break(struct uart_port + unsigned char cmdReg; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + trace(icom_port, "BREAK", 0); + cmdReg = readb(&icom_port->dram->CmdReg); + if (break_state == -1) { +@@ -1315,7 +1315,7 @@ static void icom_break(struct uart_port + } else { + writeb(cmdReg & ~CMD_SND_BREAK, &icom_port->dram->CmdReg); + } +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int icom_open(struct uart_port *port) +@@ -1365,7 +1365,7 @@ static void icom_set_termios(struct uart + unsigned long offset; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + trace(icom_port, "CHANGE_SPEED", 0); + + cflag = termios->c_cflag; +@@ -1516,7 +1516,7 @@ static void icom_set_termios(struct uart + trace(icom_port, "XR_ENAB", 0); + writeb(CMD_XMIT_RCV_ENABLE, &icom_port->dram->CmdReg); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *icom_type(struct uart_port *port) diff --git a/debian/patches-rt/0029-serial-imx-Use-port-lock-wrappers.patch b/debian/patches-rt/0029-serial-imx-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..24f582ae8 --- /dev/null +++ b/debian/patches-rt/0029-serial-imx-Use-port-lock-wrappers.patch @@ -0,0 +1,354 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:46 +0206 +Subject: [PATCH 029/134] serial: imx: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-30-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/imx.c | 84 +++++++++++++++++++++++------------------------ + 1 file changed, 42 insertions(+), 42 deletions(-) + +--- a/drivers/tty/serial/imx.c ++++ b/drivers/tty/serial/imx.c +@@ -575,7 +575,7 @@ static void imx_uart_dma_tx_callback(voi + unsigned long flags; + u32 ucr1; + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + + dma_unmap_sg(sport->port.dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE); + +@@ -600,7 +600,7 @@ static void imx_uart_dma_tx_callback(voi + imx_uart_writel(sport, ucr4, UCR4); + } + +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + } + + /* called with port.lock taken and irqs off */ +@@ -766,11 +766,11 @@ static irqreturn_t imx_uart_rtsint(int i + struct imx_port *sport = dev_id; + irqreturn_t ret; + +- spin_lock(&sport->port.lock); ++ uart_port_lock(&sport->port); + + ret = __imx_uart_rtsint(irq, dev_id); + +- spin_unlock(&sport->port.lock); ++ uart_port_unlock(&sport->port); + + return ret; + } +@@ -779,9 +779,9 @@ static irqreturn_t imx_uart_txint(int ir + { + struct imx_port *sport = dev_id; + +- spin_lock(&sport->port.lock); ++ uart_port_lock(&sport->port); + imx_uart_transmit_buffer(sport); +- spin_unlock(&sport->port.lock); ++ uart_port_unlock(&sport->port); + return IRQ_HANDLED; + } + +@@ -895,11 +895,11 @@ static irqreturn_t imx_uart_rxint(int ir + struct imx_port *sport = dev_id; + irqreturn_t ret; + +- spin_lock(&sport->port.lock); ++ uart_port_lock(&sport->port); + + ret = __imx_uart_rxint(irq, dev_id); + +- spin_unlock(&sport->port.lock); ++ uart_port_unlock(&sport->port); + + return ret; + } +@@ -962,7 +962,7 @@ static irqreturn_t imx_uart_int(int irq, + unsigned int usr1, usr2, ucr1, ucr2, ucr3, ucr4; + irqreturn_t ret = IRQ_NONE; + +- spin_lock(&sport->port.lock); ++ uart_port_lock(&sport->port); + + usr1 = imx_uart_readl(sport, USR1); + usr2 = imx_uart_readl(sport, USR2); +@@ -1032,7 +1032,7 @@ static irqreturn_t imx_uart_int(int irq, + ret = IRQ_HANDLED; + } + +- spin_unlock(&sport->port.lock); ++ uart_port_unlock(&sport->port); + + return ret; + } +@@ -1115,7 +1115,7 @@ static void imx_uart_break_ctl(struct ua + unsigned long flags; + u32 ucr1; + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + + ucr1 = imx_uart_readl(sport, UCR1) & ~UCR1_SNDBRK; + +@@ -1124,7 +1124,7 @@ static void imx_uart_break_ctl(struct ua + + imx_uart_writel(sport, ucr1, UCR1); + +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + } + + /* +@@ -1137,9 +1137,9 @@ static void imx_uart_timeout(struct time + unsigned long flags; + + if (sport->port.state) { +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + imx_uart_mctrl_check(sport); +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + + mod_timer(&sport->timer, jiffies + MCTRL_TIMEOUT); + } +@@ -1169,9 +1169,9 @@ static void imx_uart_dma_rx_callback(voi + status = dmaengine_tx_status(chan, sport->rx_cookie, &state); + + if (status == DMA_ERROR) { +- spin_lock(&sport->port.lock); ++ uart_port_lock(&sport->port); + imx_uart_clear_rx_errors(sport); +- spin_unlock(&sport->port.lock); ++ uart_port_unlock(&sport->port); + return; + } + +@@ -1200,9 +1200,9 @@ static void imx_uart_dma_rx_callback(voi + r_bytes = rx_ring->head - rx_ring->tail; + + /* If we received something, check for 0xff flood */ +- spin_lock(&sport->port.lock); ++ uart_port_lock(&sport->port); + imx_uart_check_flood(sport, imx_uart_readl(sport, USR2)); +- spin_unlock(&sport->port.lock); ++ uart_port_unlock(&sport->port); + + if (!(sport->port.ignore_status_mask & URXD_DUMMY_READ)) { + +@@ -1460,7 +1460,7 @@ static int imx_uart_startup(struct uart_ + if (!uart_console(port) && imx_uart_dma_init(sport) == 0) + dma_is_inited = 1; + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + + /* Reset fifo's and state machines */ + imx_uart_soft_reset(sport); +@@ -1533,7 +1533,7 @@ static int imx_uart_startup(struct uart_ + + imx_uart_disable_loopback_rs485(sport); + +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + + return 0; + } +@@ -1558,21 +1558,21 @@ static void imx_uart_shutdown(struct uar + sport->dma_is_rxing = 0; + } + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + imx_uart_stop_tx(port); + imx_uart_stop_rx(port); + imx_uart_disable_dma(sport); +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + imx_uart_dma_exit(sport); + } + + mctrl_gpio_disable_ms(sport->gpios); + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + ucr2 = imx_uart_readl(sport, UCR2); + ucr2 &= ~(UCR2_TXEN | UCR2_ATEN); + imx_uart_writel(sport, ucr2, UCR2); +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + + /* + * Stop our timer. +@@ -1583,7 +1583,7 @@ static void imx_uart_shutdown(struct uar + * Disable all interrupts, port and break condition. + */ + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + + ucr1 = imx_uart_readl(sport, UCR1); + ucr1 &= ~(UCR1_TRDYEN | UCR1_RRDYEN | UCR1_RTSDEN | UCR1_RXDMAEN | +@@ -1605,7 +1605,7 @@ static void imx_uart_shutdown(struct uar + ucr4 &= ~UCR4_TCEN; + imx_uart_writel(sport, ucr4, UCR4); + +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + + clk_disable_unprepare(sport->clk_per); + clk_disable_unprepare(sport->clk_ipg); +@@ -1668,7 +1668,7 @@ imx_uart_set_termios(struct uart_port *p + baud = uart_get_baud_rate(port, termios, old, 50, port->uartclk / 16); + quot = uart_get_divisor(port, baud); + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + + /* + * Read current UCR2 and save it for future use, then clear all the bits +@@ -1796,7 +1796,7 @@ imx_uart_set_termios(struct uart_port *p + if (UART_ENABLE_MS(&sport->port, termios->c_cflag)) + imx_uart_enable_ms(&sport->port); + +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + } + + static const char *imx_uart_type(struct uart_port *port) +@@ -1858,7 +1858,7 @@ static int imx_uart_poll_init(struct uar + + imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT); + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + + /* + * Be careful about the order of enabling bits here. First enable the +@@ -1886,7 +1886,7 @@ static int imx_uart_poll_init(struct uar + imx_uart_writel(sport, ucr1 | UCR1_RRDYEN, UCR1); + imx_uart_writel(sport, ucr2 | UCR2_ATEN, UCR2); + +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + + return 0; + } +@@ -2005,9 +2005,9 @@ imx_uart_console_write(struct console *c + if (sport->port.sysrq) + locked = 0; + else if (oops_in_progress) +- locked = spin_trylock_irqsave(&sport->port.lock, flags); ++ locked = uart_port_trylock_irqsave(&sport->port, &flags); + else +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + + /* + * First, save UCR1/2/3 and then disable interrupts +@@ -2035,7 +2035,7 @@ imx_uart_console_write(struct console *c + imx_uart_ucrs_restore(sport, &old_ucr); + + if (locked) +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + } + + /* +@@ -2193,10 +2193,10 @@ static enum hrtimer_restart imx_trigger_ + struct imx_port *sport = container_of(t, struct imx_port, trigger_start_tx); + unsigned long flags; + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + if (sport->tx_state == WAIT_AFTER_RTS) + imx_uart_start_tx(&sport->port); +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + + return HRTIMER_NORESTART; + } +@@ -2206,10 +2206,10 @@ static enum hrtimer_restart imx_trigger_ + struct imx_port *sport = container_of(t, struct imx_port, trigger_stop_tx); + unsigned long flags; + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + if (sport->tx_state == WAIT_AFTER_SEND) + imx_uart_stop_tx(&sport->port); +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + + return HRTIMER_NORESTART; + } +@@ -2482,9 +2482,9 @@ static void imx_uart_restore_context(str + { + unsigned long flags; + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + if (!sport->context_saved) { +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + return; + } + +@@ -2499,7 +2499,7 @@ static void imx_uart_restore_context(str + imx_uart_writel(sport, sport->saved_reg[2], UCR3); + imx_uart_writel(sport, sport->saved_reg[3], UCR4); + sport->context_saved = false; +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + } + + static void imx_uart_save_context(struct imx_port *sport) +@@ -2507,7 +2507,7 @@ static void imx_uart_save_context(struct + unsigned long flags; + + /* Save necessary regs */ +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + sport->saved_reg[0] = imx_uart_readl(sport, UCR1); + sport->saved_reg[1] = imx_uart_readl(sport, UCR2); + sport->saved_reg[2] = imx_uart_readl(sport, UCR3); +@@ -2519,7 +2519,7 @@ static void imx_uart_save_context(struct + sport->saved_reg[8] = imx_uart_readl(sport, UBMR); + sport->saved_reg[9] = imx_uart_readl(sport, IMX21_UTS); + sport->context_saved = true; +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + } + + static void imx_uart_enable_wakeup(struct imx_port *sport, bool on) diff --git a/debian/patches-rt/0030-serial-ip22zilog-Use-port-lock-wrappers.patch b/debian/patches-rt/0030-serial-ip22zilog-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..c1307a246 --- /dev/null +++ b/debian/patches-rt/0030-serial-ip22zilog-Use-port-lock-wrappers.patch @@ -0,0 +1,185 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:47 +0206 +Subject: [PATCH 030/134] serial: ip22zilog: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-31-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/ip22zilog.c | 36 ++++++++++++++++++------------------ + 1 file changed, 18 insertions(+), 18 deletions(-) + +--- a/drivers/tty/serial/ip22zilog.c ++++ b/drivers/tty/serial/ip22zilog.c +@@ -432,7 +432,7 @@ static irqreturn_t ip22zilog_interrupt(i + unsigned char r3; + bool push = false; + +- spin_lock(&up->port.lock); ++ uart_port_lock(&up->port); + r3 = read_zsreg(channel, R3); + + /* Channel A */ +@@ -448,7 +448,7 @@ static irqreturn_t ip22zilog_interrupt(i + if (r3 & CHATxIP) + ip22zilog_transmit_chars(up, channel); + } +- spin_unlock(&up->port.lock); ++ uart_port_unlock(&up->port); + + if (push) + tty_flip_buffer_push(&up->port.state->port); +@@ -458,7 +458,7 @@ static irqreturn_t ip22zilog_interrupt(i + channel = ZILOG_CHANNEL_FROM_PORT(&up->port); + push = false; + +- spin_lock(&up->port.lock); ++ uart_port_lock(&up->port); + if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) { + writeb(RES_H_IUS, &channel->control); + ZSDELAY(); +@@ -471,7 +471,7 @@ static irqreturn_t ip22zilog_interrupt(i + if (r3 & CHBTxIP) + ip22zilog_transmit_chars(up, channel); + } +- spin_unlock(&up->port.lock); ++ uart_port_unlock(&up->port); + + if (push) + tty_flip_buffer_push(&up->port.state->port); +@@ -504,11 +504,11 @@ static unsigned int ip22zilog_tx_empty(s + unsigned char status; + unsigned int ret; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + status = ip22zilog_read_channel_status(port); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + if (status & Tx_BUF_EMP) + ret = TIOCSER_TEMT; +@@ -664,7 +664,7 @@ static void ip22zilog_break_ctl(struct u + else + clear_bits |= SND_BRK; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + new_reg = (up->curregs[R5] | set_bits) & ~clear_bits; + if (new_reg != up->curregs[R5]) { +@@ -674,7 +674,7 @@ static void ip22zilog_break_ctl(struct u + write_zsreg(channel, R5, up->curregs[R5]); + } + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void __ip22zilog_reset(struct uart_ip22zilog_port *up) +@@ -735,9 +735,9 @@ static int ip22zilog_startup(struct uart + if (ZS_IS_CONS(up)) + return 0; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + __ip22zilog_startup(up); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + return 0; + } + +@@ -775,7 +775,7 @@ static void ip22zilog_shutdown(struct ua + if (ZS_IS_CONS(up)) + return; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + channel = ZILOG_CHANNEL_FROM_PORT(port); + +@@ -788,7 +788,7 @@ static void ip22zilog_shutdown(struct ua + up->curregs[R5] &= ~SND_BRK; + ip22zilog_maybe_update_regs(up, channel); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /* Shared by TTY driver and serial console setup. The port lock is held +@@ -880,7 +880,7 @@ ip22zilog_set_termios(struct uart_port * + + baud = uart_get_baud_rate(port, termios, old, 1200, 76800); + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR); + +@@ -894,7 +894,7 @@ ip22zilog_set_termios(struct uart_port * + ip22zilog_maybe_update_regs(up, ZILOG_CHANNEL_FROM_PORT(port)); + uart_update_timeout(port, termios->c_cflag, baud); + +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static const char *ip22zilog_type(struct uart_port *port) +@@ -1016,10 +1016,10 @@ ip22zilog_console_write(struct console * + struct uart_ip22zilog_port *up = &ip22zilog_port_table[con->index]; + unsigned long flags; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + uart_console_write(&up->port, s, count, ip22zilog_put_char); + udelay(2); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static int __init ip22zilog_console_setup(struct console *con, char *options) +@@ -1034,13 +1034,13 @@ static int __init ip22zilog_console_setu + + printk(KERN_INFO "Console: ttyS%d (IP22-Zilog)\n", con->index); + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + up->curregs[R15] |= BRKIE; + + __ip22zilog_startup(up); + +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + if (options) + uart_parse_options(options, &baud, &parity, &bits, &flow); diff --git a/debian/patches-rt/0031-serial-jsm-Use-port-lock-wrappers.patch b/debian/patches-rt/0031-serial-jsm-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..4326b333a --- /dev/null +++ b/debian/patches-rt/0031-serial-jsm-Use-port-lock-wrappers.patch @@ -0,0 +1,124 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:48 +0206 +Subject: [PATCH 031/134] serial: jsm: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-32-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/jsm/jsm_neo.c | 4 ++-- + drivers/tty/serial/jsm/jsm_tty.c | 16 ++++++++-------- + 2 files changed, 10 insertions(+), 10 deletions(-) + +--- a/drivers/tty/serial/jsm/jsm_neo.c ++++ b/drivers/tty/serial/jsm/jsm_neo.c +@@ -816,9 +816,9 @@ static void neo_parse_isr(struct jsm_boa + /* Parse any modem signal changes */ + jsm_dbg(INTR, &ch->ch_bd->pci_dev, + "MOD_STAT: sending to parse_modem_sigs\n"); +- spin_lock_irqsave(&ch->uart_port.lock, lock_flags); ++ uart_port_lock_irqsave(&ch->uart_port, &lock_flags); + neo_parse_modem(ch, readb(&ch->ch_neo_uart->msr)); +- spin_unlock_irqrestore(&ch->uart_port.lock, lock_flags); ++ uart_port_unlock_irqrestore(&ch->uart_port, lock_flags); + } + } + +--- a/drivers/tty/serial/jsm/jsm_tty.c ++++ b/drivers/tty/serial/jsm/jsm_tty.c +@@ -152,14 +152,14 @@ static void jsm_tty_send_xchar(struct ua + container_of(port, struct jsm_channel, uart_port); + struct ktermios *termios; + +- spin_lock_irqsave(&port->lock, lock_flags); ++ uart_port_lock_irqsave(port, &lock_flags); + termios = &port->state->port.tty->termios; + if (ch == termios->c_cc[VSTART]) + channel->ch_bd->bd_ops->send_start_character(channel); + + if (ch == termios->c_cc[VSTOP]) + channel->ch_bd->bd_ops->send_stop_character(channel); +- spin_unlock_irqrestore(&port->lock, lock_flags); ++ uart_port_unlock_irqrestore(port, lock_flags); + } + + static void jsm_tty_stop_rx(struct uart_port *port) +@@ -176,13 +176,13 @@ static void jsm_tty_break(struct uart_po + struct jsm_channel *channel = + container_of(port, struct jsm_channel, uart_port); + +- spin_lock_irqsave(&port->lock, lock_flags); ++ uart_port_lock_irqsave(port, &lock_flags); + if (break_state == -1) + channel->ch_bd->bd_ops->send_break(channel); + else + channel->ch_bd->bd_ops->clear_break(channel); + +- spin_unlock_irqrestore(&port->lock, lock_flags); ++ uart_port_unlock_irqrestore(port, lock_flags); + } + + static int jsm_tty_open(struct uart_port *port) +@@ -241,7 +241,7 @@ static int jsm_tty_open(struct uart_port + channel->ch_cached_lsr = 0; + channel->ch_stops_sent = 0; + +- spin_lock_irqsave(&port->lock, lock_flags); ++ uart_port_lock_irqsave(port, &lock_flags); + termios = &port->state->port.tty->termios; + channel->ch_c_cflag = termios->c_cflag; + channel->ch_c_iflag = termios->c_iflag; +@@ -261,7 +261,7 @@ static int jsm_tty_open(struct uart_port + jsm_carrier(channel); + + channel->ch_open_count++; +- spin_unlock_irqrestore(&port->lock, lock_flags); ++ uart_port_unlock_irqrestore(port, lock_flags); + + jsm_dbg(OPEN, &channel->ch_bd->pci_dev, "finish\n"); + return 0; +@@ -307,7 +307,7 @@ static void jsm_tty_set_termios(struct u + struct jsm_channel *channel = + container_of(port, struct jsm_channel, uart_port); + +- spin_lock_irqsave(&port->lock, lock_flags); ++ uart_port_lock_irqsave(port, &lock_flags); + channel->ch_c_cflag = termios->c_cflag; + channel->ch_c_iflag = termios->c_iflag; + channel->ch_c_oflag = termios->c_oflag; +@@ -317,7 +317,7 @@ static void jsm_tty_set_termios(struct u + + channel->ch_bd->bd_ops->param(channel); + jsm_carrier(channel); +- spin_unlock_irqrestore(&port->lock, lock_flags); ++ uart_port_unlock_irqrestore(port, lock_flags); + } + + static const char *jsm_tty_type(struct uart_port *port) diff --git a/debian/patches-rt/0032-serial-liteuart-Use-port-lock-wrappers.patch b/debian/patches-rt/0032-serial-liteuart-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..ae679c098 --- /dev/null +++ b/debian/patches-rt/0032-serial-liteuart-Use-port-lock-wrappers.patch @@ -0,0 +1,110 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:49 +0206 +Subject: [PATCH 032/134] serial: liteuart: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Acked-by: Gabriel Somlo +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-33-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/liteuart.c | 20 ++++++++++---------- + 1 file changed, 10 insertions(+), 10 deletions(-) + +--- a/drivers/tty/serial/liteuart.c ++++ b/drivers/tty/serial/liteuart.c +@@ -139,13 +139,13 @@ static irqreturn_t liteuart_interrupt(in + * if polling, the context would be "in_serving_softirq", so use + * irq[save|restore] spin_lock variants to cover all possibilities + */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + isr = litex_read8(port->membase + OFF_EV_PENDING) & uart->irq_reg; + if (isr & EV_RX) + liteuart_rx_chars(port); + if (isr & EV_TX) + liteuart_tx_chars(port); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return IRQ_RETVAL(isr); + } +@@ -195,10 +195,10 @@ static int liteuart_startup(struct uart_ + } + } + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + /* only enabling rx irqs during startup */ + liteuart_update_irq_reg(port, true, EV_RX); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + if (!port->irq) { + timer_setup(&uart->timer, liteuart_timer, 0); +@@ -213,9 +213,9 @@ static void liteuart_shutdown(struct uar + struct liteuart_port *uart = to_liteuart_port(port); + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + liteuart_update_irq_reg(port, false, EV_RX | EV_TX); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + if (port->irq) + free_irq(port->irq, port); +@@ -229,13 +229,13 @@ static void liteuart_set_termios(struct + unsigned int baud; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* update baudrate */ + baud = uart_get_baud_rate(port, new, old, 0, 460800); + uart_update_timeout(port, new->c_cflag, baud); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *liteuart_type(struct uart_port *port) +@@ -382,9 +382,9 @@ static void liteuart_console_write(struc + uart = (struct liteuart_port *)xa_load(&liteuart_array, co->index); + port = &uart->port; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + uart_console_write(port, s, count, liteuart_putchar); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int liteuart_console_setup(struct console *co, char *options) diff --git a/debian/patches-rt/0033-serial-lpc32xx_hs-Use-port-lock-wrappers.patch b/debian/patches-rt/0033-serial-lpc32xx_hs-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..06518e846 --- /dev/null +++ b/debian/patches-rt/0033-serial-lpc32xx_hs-Use-port-lock-wrappers.patch @@ -0,0 +1,148 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:50 +0206 +Subject: [PATCH 033/134] serial: lpc32xx_hs: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-34-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/lpc32xx_hs.c | 26 +++++++++++++------------- + 1 file changed, 13 insertions(+), 13 deletions(-) + +--- a/drivers/tty/serial/lpc32xx_hs.c ++++ b/drivers/tty/serial/lpc32xx_hs.c +@@ -140,15 +140,15 @@ static void lpc32xx_hsuart_console_write + if (up->port.sysrq) + locked = 0; + else if (oops_in_progress) +- locked = spin_trylock(&up->port.lock); ++ locked = uart_port_trylock(&up->port); + else +- spin_lock(&up->port.lock); ++ uart_port_lock(&up->port); + + uart_console_write(&up->port, s, count, lpc32xx_hsuart_console_putchar); + wait_for_xmit_empty(&up->port); + + if (locked) +- spin_unlock(&up->port.lock); ++ uart_port_unlock(&up->port); + local_irq_restore(flags); + } + +@@ -298,7 +298,7 @@ static irqreturn_t serial_lpc32xx_interr + struct tty_port *tport = &port->state->port; + u32 status; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + /* Read UART status and clear latched interrupts */ + status = readl(LPC32XX_HSUART_IIR(port->membase)); +@@ -333,7 +333,7 @@ static irqreturn_t serial_lpc32xx_interr + __serial_lpc32xx_tx(port); + } + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return IRQ_HANDLED; + } +@@ -404,14 +404,14 @@ static void serial_lpc32xx_break_ctl(str + unsigned long flags; + u32 tmp; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + tmp = readl(LPC32XX_HSUART_CTRL(port->membase)); + if (break_state != 0) + tmp |= LPC32XX_HSU_BREAK; + else + tmp &= ~LPC32XX_HSU_BREAK; + writel(tmp, LPC32XX_HSUART_CTRL(port->membase)); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /* port->lock is not held. */ +@@ -421,7 +421,7 @@ static int serial_lpc32xx_startup(struct + unsigned long flags; + u32 tmp; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + __serial_uart_flush(port); + +@@ -441,7 +441,7 @@ static int serial_lpc32xx_startup(struct + + lpc32xx_loopback_set(port->mapbase, 0); /* get out of loopback mode */ + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + retval = request_irq(port->irq, serial_lpc32xx_interrupt, + 0, MODNAME, port); +@@ -458,7 +458,7 @@ static void serial_lpc32xx_shutdown(stru + u32 tmp; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + tmp = LPC32XX_HSU_TX_TL8B | LPC32XX_HSU_RX_TL32B | + LPC32XX_HSU_OFFSET(20) | LPC32XX_HSU_TMO_INACT_4B; +@@ -466,7 +466,7 @@ static void serial_lpc32xx_shutdown(stru + + lpc32xx_loopback_set(port->mapbase, 1); /* go to loopback mode */ + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + free_irq(port->irq, port); + } +@@ -491,7 +491,7 @@ static void serial_lpc32xx_set_termios(s + + quot = __serial_get_clock_div(port->uartclk, baud); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Ignore characters? */ + tmp = readl(LPC32XX_HSUART_CTRL(port->membase)); +@@ -505,7 +505,7 @@ static void serial_lpc32xx_set_termios(s + + uart_update_timeout(port, termios->c_cflag, baud); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + /* Don't rewrite B0 */ + if (tty_termios_baud_rate(termios)) diff --git a/debian/patches-rt/0034-serial-ma35d1-Use-port-lock-wrappers.patch b/debian/patches-rt/0034-serial-ma35d1-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..995bad9aa --- /dev/null +++ b/debian/patches-rt/0034-serial-ma35d1-Use-port-lock-wrappers.patch @@ -0,0 +1,117 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:51 +0206 +Subject: [PATCH 034/134] serial: ma35d1: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-35-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/ma35d1_serial.c | 22 +++++++++++----------- + 1 file changed, 11 insertions(+), 11 deletions(-) + +--- a/drivers/tty/serial/ma35d1_serial.c ++++ b/drivers/tty/serial/ma35d1_serial.c +@@ -269,16 +269,16 @@ static void receive_chars(struct uart_ma + if (uart_handle_sysrq_char(&up->port, ch)) + continue; + +- spin_lock(&up->port.lock); ++ uart_port_lock(&up->port); + uart_insert_char(&up->port, fsr, MA35_FSR_RX_OVER_IF, ch, flag); +- spin_unlock(&up->port.lock); ++ uart_port_unlock(&up->port); + + fsr = serial_in(up, MA35_FSR_REG); + } while (!(fsr & MA35_FSR_RX_EMPTY) && (max_count-- > 0)); + +- spin_lock(&up->port.lock); ++ uart_port_lock(&up->port); + tty_flip_buffer_push(&up->port.state->port); +- spin_unlock(&up->port.lock); ++ uart_port_unlock(&up->port); + } + + static irqreturn_t ma35d1serial_interrupt(int irq, void *dev_id) +@@ -364,14 +364,14 @@ static void ma35d1serial_break_ctl(struc + unsigned long flags; + u32 lcr; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + lcr = serial_in(up, MA35_LCR_REG); + if (break_state != 0) + lcr |= MA35_LCR_BREAK; + else + lcr &= ~MA35_LCR_BREAK; + serial_out(up, MA35_LCR_REG, lcr); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static int ma35d1serial_startup(struct uart_port *port) +@@ -441,7 +441,7 @@ static void ma35d1serial_set_termios(str + * Ok, we're now changing the port state. Do it with + * interrupts disabled. + */ +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + up->port.read_status_mask = MA35_FSR_RX_OVER_IF; + if (termios->c_iflag & INPCK) +@@ -475,7 +475,7 @@ static void ma35d1serial_set_termios(str + + serial_out(up, MA35_LCR_REG, lcr); + +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static const char *ma35d1serial_type(struct uart_port *port) +@@ -560,9 +560,9 @@ static void ma35d1serial_console_write(s + if (up->port.sysrq) + locked = 0; + else if (oops_in_progress) +- locked = spin_trylock_irqsave(&up->port.lock, flags); ++ locked = uart_port_trylock_irqsave(&up->port, &flags); + else +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + /* + * First save the IER then disable the interrupts +@@ -576,7 +576,7 @@ static void ma35d1serial_console_write(s + serial_out(up, MA35_IER_REG, ier); + + if (locked) +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static int __init ma35d1serial_console_setup(struct console *co, char *options) diff --git a/debian/patches-rt/0035-serial-mcf-Use-port-lock-wrappers.patch b/debian/patches-rt/0035-serial-mcf-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..966618a3e --- /dev/null +++ b/debian/patches-rt/0035-serial-mcf-Use-port-lock-wrappers.patch @@ -0,0 +1,127 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:52 +0206 +Subject: [PATCH 035/134] serial: mcf: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-36-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/mcf.c | 20 ++++++++++---------- + 1 file changed, 10 insertions(+), 10 deletions(-) + +--- a/drivers/tty/serial/mcf.c ++++ b/drivers/tty/serial/mcf.c +@@ -135,12 +135,12 @@ static void mcf_break_ctl(struct uart_po + { + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + if (break_state == -1) + writeb(MCFUART_UCR_CMDBREAKSTART, port->membase + MCFUART_UCR); + else + writeb(MCFUART_UCR_CMDBREAKSTOP, port->membase + MCFUART_UCR); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /****************************************************************************/ +@@ -150,7 +150,7 @@ static int mcf_startup(struct uart_port + struct mcf_uart *pp = container_of(port, struct mcf_uart, port); + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Reset UART, get it into known state... */ + writeb(MCFUART_UCR_CMDRESETRX, port->membase + MCFUART_UCR); +@@ -164,7 +164,7 @@ static int mcf_startup(struct uart_port + pp->imr = MCFUART_UIR_RXREADY; + writeb(pp->imr, port->membase + MCFUART_UIMR); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return 0; + } +@@ -176,7 +176,7 @@ static void mcf_shutdown(struct uart_por + struct mcf_uart *pp = container_of(port, struct mcf_uart, port); + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Disable all interrupts now */ + pp->imr = 0; +@@ -186,7 +186,7 @@ static void mcf_shutdown(struct uart_por + writeb(MCFUART_UCR_CMDRESETRX, port->membase + MCFUART_UCR); + writeb(MCFUART_UCR_CMDRESETTX, port->membase + MCFUART_UCR); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /****************************************************************************/ +@@ -252,7 +252,7 @@ static void mcf_set_termios(struct uart_ + mr2 |= MCFUART_MR2_TXCTS; + } + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + if (port->rs485.flags & SER_RS485_ENABLED) { + dev_dbg(port->dev, "Setting UART to RS485\n"); + mr2 |= MCFUART_MR2_TXRTS; +@@ -273,7 +273,7 @@ static void mcf_set_termios(struct uart_ + port->membase + MCFUART_UCSR); + writeb(MCFUART_UCR_RXENABLE | MCFUART_UCR_TXENABLE, + port->membase + MCFUART_UCR); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /****************************************************************************/ +@@ -350,7 +350,7 @@ static irqreturn_t mcf_interrupt(int irq + + isr = readb(port->membase + MCFUART_UISR) & pp->imr; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + if (isr & MCFUART_UIR_RXREADY) { + mcf_rx_chars(pp); + ret = IRQ_HANDLED; +@@ -359,7 +359,7 @@ static irqreturn_t mcf_interrupt(int irq + mcf_tx_chars(pp); + ret = IRQ_HANDLED; + } +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return ret; + } diff --git a/debian/patches-rt/0036-serial-men_z135_uart-Use-port-lock-wrappers.patch b/debian/patches-rt/0036-serial-men_z135_uart-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..11019689b --- /dev/null +++ b/debian/patches-rt/0036-serial-men_z135_uart-Use-port-lock-wrappers.patch @@ -0,0 +1,76 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:53 +0206 +Subject: [PATCH 036/134] serial: men_z135_uart: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-37-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/men_z135_uart.c | 8 ++++---- + 1 file changed, 4 insertions(+), 4 deletions(-) + +--- a/drivers/tty/serial/men_z135_uart.c ++++ b/drivers/tty/serial/men_z135_uart.c +@@ -392,7 +392,7 @@ static irqreturn_t men_z135_intr(int irq + if (!irq_id) + goto out; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + /* It's save to write to IIR[7:6] RXC[9:8] */ + iowrite8(irq_id, port->membase + MEN_Z135_STAT_REG); + +@@ -418,7 +418,7 @@ static irqreturn_t men_z135_intr(int irq + handled = true; + } + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + out: + return IRQ_RETVAL(handled); + } +@@ -708,7 +708,7 @@ static void men_z135_set_termios(struct + + baud = uart_get_baud_rate(port, termios, old, 0, uart_freq / 16); + +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + if (tty_termios_baud_rate(termios)) + tty_termios_encode_baud_rate(termios, baud, baud); + +@@ -716,7 +716,7 @@ static void men_z135_set_termios(struct + iowrite32(bd_reg, port->membase + MEN_Z135_BAUD_REG); + + uart_update_timeout(port, termios->c_cflag, baud); +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + } + + static const char *men_z135_type(struct uart_port *port) diff --git a/debian/patches-rt/0037-serial-meson-Use-port-lock-wrappers.patch b/debian/patches-rt/0037-serial-meson-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..d2efb460b --- /dev/null +++ b/debian/patches-rt/0037-serial-meson-Use-port-lock-wrappers.patch @@ -0,0 +1,168 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:54 +0206 +Subject: [PATCH 037/134] serial: meson: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Acked-by: Neil Armstrong +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-38-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/meson_uart.c | 30 +++++++++++++++--------------- + 1 file changed, 15 insertions(+), 15 deletions(-) + +--- a/drivers/tty/serial/meson_uart.c ++++ b/drivers/tty/serial/meson_uart.c +@@ -129,14 +129,14 @@ static void meson_uart_shutdown(struct u + + free_irq(port->irq, port); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + val = readl(port->membase + AML_UART_CONTROL); + val &= ~AML_UART_RX_EN; + val &= ~(AML_UART_RX_INT_EN | AML_UART_TX_INT_EN); + writel(val, port->membase + AML_UART_CONTROL); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void meson_uart_start_tx(struct uart_port *port) +@@ -238,7 +238,7 @@ static irqreturn_t meson_uart_interrupt( + { + struct uart_port *port = (struct uart_port *)dev_id; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + if (!(readl(port->membase + AML_UART_STATUS) & AML_UART_RX_EMPTY)) + meson_receive_chars(port); +@@ -248,7 +248,7 @@ static irqreturn_t meson_uart_interrupt( + meson_uart_start_tx(port); + } + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return IRQ_HANDLED; + } +@@ -284,7 +284,7 @@ static int meson_uart_startup(struct uar + u32 val; + int ret = 0; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + val = readl(port->membase + AML_UART_CONTROL); + val |= AML_UART_CLEAR_ERR; +@@ -301,7 +301,7 @@ static int meson_uart_startup(struct uar + val = (AML_UART_RECV_IRQ(1) | AML_UART_XMIT_IRQ(port->fifosize / 2)); + writel(val, port->membase + AML_UART_MISC); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + ret = request_irq(port->irq, meson_uart_interrupt, 0, + port->name, port); +@@ -341,7 +341,7 @@ static void meson_uart_set_termios(struc + unsigned long flags; + u32 val; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + cflags = termios->c_cflag; + iflags = termios->c_iflag; +@@ -405,7 +405,7 @@ static void meson_uart_set_termios(struc + AML_UART_FRAME_ERR; + + uart_update_timeout(port, termios->c_cflag, baud); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int meson_uart_verify_port(struct uart_port *port, +@@ -464,14 +464,14 @@ static int meson_uart_poll_get_char(stru + u32 c; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + if (readl(port->membase + AML_UART_STATUS) & AML_UART_RX_EMPTY) + c = NO_POLL_CHAR; + else + c = readl(port->membase + AML_UART_RFIFO); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return c; + } +@@ -482,7 +482,7 @@ static void meson_uart_poll_put_char(str + u32 reg; + int ret; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Wait until FIFO is empty or timeout */ + ret = readl_poll_timeout_atomic(port->membase + AML_UART_STATUS, reg, +@@ -506,7 +506,7 @@ static void meson_uart_poll_put_char(str + dev_err(port->dev, "Timeout waiting for UART TX EMPTY\n"); + + out: +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + #endif /* CONFIG_CONSOLE_POLL */ +@@ -563,9 +563,9 @@ static void meson_serial_port_write(stru + if (port->sysrq) { + locked = 0; + } else if (oops_in_progress) { +- locked = spin_trylock(&port->lock); ++ locked = uart_port_trylock(port); + } else { +- spin_lock(&port->lock); ++ uart_port_lock(port); + locked = 1; + } + +@@ -577,7 +577,7 @@ static void meson_serial_port_write(stru + writel(val, port->membase + AML_UART_CONTROL); + + if (locked) +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + local_irq_restore(flags); + } + diff --git a/debian/patches-rt/0038-serial-milbeaut_usio-Use-port-lock-wrappers.patch b/debian/patches-rt/0038-serial-milbeaut_usio-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..47b1b7f3c --- /dev/null +++ b/debian/patches-rt/0038-serial-milbeaut_usio-Use-port-lock-wrappers.patch @@ -0,0 +1,101 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:55 +0206 +Subject: [PATCH 038/134] serial: milbeaut_usio: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-39-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/milbeaut_usio.c | 16 ++++++++-------- + 1 file changed, 8 insertions(+), 8 deletions(-) + +--- a/drivers/tty/serial/milbeaut_usio.c ++++ b/drivers/tty/serial/milbeaut_usio.c +@@ -207,9 +207,9 @@ static irqreturn_t mlb_usio_rx_irq(int i + { + struct uart_port *port = dev_id; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + mlb_usio_rx_chars(port); +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return IRQ_HANDLED; + } +@@ -218,10 +218,10 @@ static irqreturn_t mlb_usio_tx_irq(int i + { + struct uart_port *port = dev_id; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + if (readb(port->membase + MLB_USIO_REG_SSR) & MLB_USIO_SSR_TBI) + mlb_usio_tx_chars(port); +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return IRQ_HANDLED; + } +@@ -267,7 +267,7 @@ static int mlb_usio_startup(struct uart_ + escr = readb(port->membase + MLB_USIO_REG_ESCR); + if (of_property_read_bool(port->dev->of_node, "auto-flow-control")) + escr |= MLB_USIO_ESCR_FLWEN; +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + writeb(0, port->membase + MLB_USIO_REG_SCR); + writeb(escr, port->membase + MLB_USIO_REG_ESCR); + writeb(MLB_USIO_SCR_UPCL, port->membase + MLB_USIO_REG_SCR); +@@ -282,7 +282,7 @@ static int mlb_usio_startup(struct uart_ + + writeb(MLB_USIO_SCR_TXE | MLB_USIO_SCR_RIE | MLB_USIO_SCR_TBIE | + MLB_USIO_SCR_RXE, port->membase + MLB_USIO_REG_SCR); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return 0; + } +@@ -337,7 +337,7 @@ static void mlb_usio_set_termios(struct + else + quot = 0; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + uart_update_timeout(port, termios->c_cflag, baud); + port->read_status_mask = MLB_USIO_SSR_ORE | MLB_USIO_SSR_RDRF | + MLB_USIO_SSR_TDRE; +@@ -367,7 +367,7 @@ static void mlb_usio_set_termios(struct + writew(BIT(12), port->membase + MLB_USIO_REG_FBYTE); + writeb(MLB_USIO_SCR_RIE | MLB_USIO_SCR_RXE | MLB_USIO_SCR_TBIE | + MLB_USIO_SCR_TXE, port->membase + MLB_USIO_REG_SCR); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *mlb_usio_type(struct uart_port *port) diff --git a/debian/patches-rt/0039-serial-mpc52xx-Use-port-lock-wrappers.patch b/debian/patches-rt/0039-serial-mpc52xx-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..ee7014a92 --- /dev/null +++ b/debian/patches-rt/0039-serial-mpc52xx-Use-port-lock-wrappers.patch @@ -0,0 +1,89 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:56 +0206 +Subject: [PATCH 039/134] serial: mpc52xx: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-40-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/mpc52xx_uart.c | 12 ++++++------ + 1 file changed, 6 insertions(+), 6 deletions(-) + +--- a/drivers/tty/serial/mpc52xx_uart.c ++++ b/drivers/tty/serial/mpc52xx_uart.c +@@ -1096,14 +1096,14 @@ static void + mpc52xx_uart_break_ctl(struct uart_port *port, int ctl) + { + unsigned long flags; +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + if (ctl == -1) + psc_ops->command(port, MPC52xx_PSC_START_BRK); + else + psc_ops->command(port, MPC52xx_PSC_STOP_BRK); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int +@@ -1214,7 +1214,7 @@ mpc52xx_uart_set_termios(struct uart_por + } + + /* Get the lock */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Do our best to flush TX & RX, so we don't lose anything */ + /* But we don't wait indefinitely ! */ +@@ -1250,7 +1250,7 @@ mpc52xx_uart_set_termios(struct uart_por + psc_ops->command(port, MPC52xx_PSC_RX_ENABLE); + + /* We're all set, release the lock */ +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char * +@@ -1477,11 +1477,11 @@ mpc52xx_uart_int(int irq, void *dev_id) + struct uart_port *port = dev_id; + irqreturn_t ret; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + ret = psc_ops->handle_irq(port); + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return ret; + } diff --git a/debian/patches-rt/0040-serial-mps2-uart-Use-port-lock-wrappers.patch b/debian/patches-rt/0040-serial-mps2-uart-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..a626bdb03 --- /dev/null +++ b/debian/patches-rt/0040-serial-mps2-uart-Use-port-lock-wrappers.patch @@ -0,0 +1,103 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:57 +0206 +Subject: [PATCH 040/134] serial: mps2-uart: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-41-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/mps2-uart.c | 16 ++++++++-------- + 1 file changed, 8 insertions(+), 8 deletions(-) + +--- a/drivers/tty/serial/mps2-uart.c ++++ b/drivers/tty/serial/mps2-uart.c +@@ -188,12 +188,12 @@ static irqreturn_t mps2_uart_rxirq(int i + if (unlikely(!(irqflag & UARTn_INT_RX))) + return IRQ_NONE; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + mps2_uart_write8(port, UARTn_INT_RX, UARTn_INT); + mps2_uart_rx_chars(port); + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return IRQ_HANDLED; + } +@@ -206,12 +206,12 @@ static irqreturn_t mps2_uart_txirq(int i + if (unlikely(!(irqflag & UARTn_INT_TX))) + return IRQ_NONE; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + mps2_uart_write8(port, UARTn_INT_TX, UARTn_INT); + mps2_uart_tx_chars(port); + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return IRQ_HANDLED; + } +@@ -222,7 +222,7 @@ static irqreturn_t mps2_uart_oerrirq(int + struct uart_port *port = data; + u8 irqflag = mps2_uart_read8(port, UARTn_INT); + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + if (irqflag & UARTn_INT_RX_OVERRUN) { + struct tty_port *tport = &port->state->port; +@@ -244,7 +244,7 @@ static irqreturn_t mps2_uart_oerrirq(int + handled = IRQ_HANDLED; + } + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return handled; + } +@@ -356,12 +356,12 @@ mps2_uart_set_termios(struct uart_port * + + bauddiv = DIV_ROUND_CLOSEST(port->uartclk, baud); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + uart_update_timeout(port, termios->c_cflag, baud); + mps2_uart_write32(port, bauddiv, UARTn_BAUDDIV); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + if (tty_termios_baud_rate(termios)) + tty_termios_encode_baud_rate(termios, baud, baud); diff --git a/debian/patches-rt/0041-serial-msm-Use-port-lock-wrappers.patch b/debian/patches-rt/0041-serial-msm-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..89b845330 --- /dev/null +++ b/debian/patches-rt/0041-serial-msm-Use-port-lock-wrappers.patch @@ -0,0 +1,185 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:58 +0206 +Subject: [PATCH 041/134] serial: msm: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Reviewed-by: Bjorn Andersson +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-42-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/msm_serial.c | 38 +++++++++++++++++++------------------- + 1 file changed, 19 insertions(+), 19 deletions(-) + +--- a/drivers/tty/serial/msm_serial.c ++++ b/drivers/tty/serial/msm_serial.c +@@ -444,7 +444,7 @@ static void msm_complete_tx_dma(void *ar + unsigned int count; + u32 val; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Already stopped */ + if (!dma->count) +@@ -476,7 +476,7 @@ static void msm_complete_tx_dma(void *ar + + msm_handle_tx(port); + done: +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int msm_handle_tx_dma(struct msm_port *msm_port, unsigned int count) +@@ -549,7 +549,7 @@ static void msm_complete_rx_dma(void *ar + unsigned long flags; + u32 val; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Already stopped */ + if (!dma->count) +@@ -587,16 +587,16 @@ static void msm_complete_rx_dma(void *ar + if (!(port->read_status_mask & MSM_UART_SR_RX_BREAK)) + flag = TTY_NORMAL; + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + sysrq = uart_handle_sysrq_char(port, dma->virt[i]); +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + if (!sysrq) + tty_insert_flip_char(tport, dma->virt[i], flag); + } + + msm_start_rx_dma(msm_port); + done: +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + if (count) + tty_flip_buffer_push(tport); +@@ -762,9 +762,9 @@ static void msm_handle_rx_dm(struct uart + if (!(port->read_status_mask & MSM_UART_SR_RX_BREAK)) + flag = TTY_NORMAL; + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + sysrq = uart_handle_sysrq_char(port, buf[i]); +- spin_lock(&port->lock); ++ uart_port_lock(port); + if (!sysrq) + tty_insert_flip_char(tport, buf[i], flag); + } +@@ -824,9 +824,9 @@ static void msm_handle_rx(struct uart_po + else if (sr & MSM_UART_SR_PAR_FRAME_ERR) + flag = TTY_FRAME; + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + sysrq = uart_handle_sysrq_char(port, c); +- spin_lock(&port->lock); ++ uart_port_lock(port); + if (!sysrq) + tty_insert_flip_char(tport, c, flag); + } +@@ -951,7 +951,7 @@ static irqreturn_t msm_uart_irq(int irq, + unsigned int misr; + u32 val; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + misr = msm_read(port, MSM_UART_MISR); + msm_write(port, 0, MSM_UART_IMR); /* disable interrupt */ + +@@ -983,7 +983,7 @@ static irqreturn_t msm_uart_irq(int irq, + msm_handle_delta_cts(port); + + msm_write(port, msm_port->imr, MSM_UART_IMR); /* restore interrupt */ +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return IRQ_HANDLED; + } +@@ -1128,13 +1128,13 @@ static int msm_set_baud_rate(struct uart + unsigned long flags, rate; + + flags = *saved_flags; +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + entry = msm_find_best_baud(port, baud, &rate); + clk_set_rate(msm_port->clk, rate); + baud = rate / 16 / entry->divisor; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + *saved_flags = flags; + port->uartclk = rate; + +@@ -1266,7 +1266,7 @@ static void msm_set_termios(struct uart_ + unsigned long flags; + unsigned int baud, mr; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + if (dma->chan) /* Terminate if any */ + msm_stop_dma(port, dma); +@@ -1338,7 +1338,7 @@ static void msm_set_termios(struct uart_ + /* Try to use DMA */ + msm_start_rx_dma(msm_port); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *msm_type(struct uart_port *port) +@@ -1620,9 +1620,9 @@ static void __msm_console_write(struct u + if (port->sysrq) + locked = 0; + else if (oops_in_progress) +- locked = spin_trylock(&port->lock); ++ locked = uart_port_trylock(port); + else +- spin_lock(&port->lock); ++ uart_port_lock(port); + + if (is_uartdm) + msm_reset_dm_count(port, count); +@@ -1661,7 +1661,7 @@ static void __msm_console_write(struct u + } + + if (locked) +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + local_irq_restore(flags); + } diff --git a/debian/patches-rt/0042-serial-mvebu-uart-Use-port-lock-wrappers.patch b/debian/patches-rt/0042-serial-mvebu-uart-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..28b2c3b46 --- /dev/null +++ b/debian/patches-rt/0042-serial-mvebu-uart-Use-port-lock-wrappers.patch @@ -0,0 +1,108 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:43:59 +0206 +Subject: [PATCH 042/134] serial: mvebu-uart: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-43-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/mvebu-uart.c | 18 +++++++++--------- + 1 file changed, 9 insertions(+), 9 deletions(-) + +--- a/drivers/tty/serial/mvebu-uart.c ++++ b/drivers/tty/serial/mvebu-uart.c +@@ -187,9 +187,9 @@ static unsigned int mvebu_uart_tx_empty( + unsigned long flags; + unsigned int st; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + st = readl(port->membase + UART_STAT); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return (st & STAT_TX_EMP) ? TIOCSER_TEMT : 0; + } +@@ -249,14 +249,14 @@ static void mvebu_uart_break_ctl(struct + unsigned int ctl; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + ctl = readl(port->membase + UART_CTRL(port)); + if (brk == -1) + ctl |= CTRL_SND_BRK_SEQ; + else + ctl &= ~CTRL_SND_BRK_SEQ; + writel(ctl, port->membase + UART_CTRL(port)); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void mvebu_uart_rx_chars(struct uart_port *port, unsigned int status) +@@ -540,7 +540,7 @@ static void mvebu_uart_set_termios(struc + unsigned long flags; + unsigned int baud, min_baud, max_baud; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + port->read_status_mask = STAT_RX_RDY(port) | STAT_OVR_ERR | + STAT_TX_RDY(port) | STAT_TX_FIFO_FUL; +@@ -589,7 +589,7 @@ static void mvebu_uart_set_termios(struc + uart_update_timeout(port, termios->c_cflag, baud); + } + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *mvebu_uart_type(struct uart_port *port) +@@ -735,9 +735,9 @@ static void mvebu_uart_console_write(str + int locked = 1; + + if (oops_in_progress) +- locked = spin_trylock_irqsave(&port->lock, flags); ++ locked = uart_port_trylock_irqsave(port, &flags); + else +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + ier = readl(port->membase + UART_CTRL(port)) & CTRL_BRK_INT; + intr = readl(port->membase + UART_INTR(port)) & +@@ -758,7 +758,7 @@ static void mvebu_uart_console_write(str + } + + if (locked) +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int mvebu_uart_console_setup(struct console *co, char *options) diff --git a/debian/patches-rt/0043-serial-omap-Use-port-lock-wrappers.patch b/debian/patches-rt/0043-serial-omap-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..a79d6253c --- /dev/null +++ b/debian/patches-rt/0043-serial-omap-Use-port-lock-wrappers.patch @@ -0,0 +1,180 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:00 +0206 +Subject: [PATCH 043/134] serial: omap: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-44-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/omap-serial.c | 38 +++++++++++++++++++------------------- + 1 file changed, 19 insertions(+), 19 deletions(-) + +--- a/drivers/tty/serial/omap-serial.c ++++ b/drivers/tty/serial/omap-serial.c +@@ -390,10 +390,10 @@ static void serial_omap_throttle(struct + struct uart_omap_port *up = to_uart_omap_port(port); + unsigned long flags; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + up->ier &= ~(UART_IER_RLSI | UART_IER_RDI); + serial_out(up, UART_IER, up->ier); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static void serial_omap_unthrottle(struct uart_port *port) +@@ -401,10 +401,10 @@ static void serial_omap_unthrottle(struc + struct uart_omap_port *up = to_uart_omap_port(port); + unsigned long flags; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + up->ier |= UART_IER_RLSI | UART_IER_RDI; + serial_out(up, UART_IER, up->ier); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static unsigned int check_modem_status(struct uart_omap_port *up) +@@ -527,7 +527,7 @@ static irqreturn_t serial_omap_irq(int i + irqreturn_t ret = IRQ_NONE; + int max_count = 256; + +- spin_lock(&up->port.lock); ++ uart_port_lock(&up->port); + + do { + iir = serial_in(up, UART_IIR); +@@ -563,7 +563,7 @@ static irqreturn_t serial_omap_irq(int i + } + } while (max_count--); + +- spin_unlock(&up->port.lock); ++ uart_port_unlock(&up->port); + + tty_flip_buffer_push(&up->port.state->port); + +@@ -579,9 +579,9 @@ static unsigned int serial_omap_tx_empty + unsigned int ret = 0; + + dev_dbg(up->port.dev, "serial_omap_tx_empty+%d\n", up->port.line); +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0; +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + return ret; + } +@@ -647,13 +647,13 @@ static void serial_omap_break_ctl(struct + unsigned long flags; + + dev_dbg(up->port.dev, "serial_omap_break_ctl+%d\n", up->port.line); +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + if (break_state == -1) + up->lcr |= UART_LCR_SBC; + else + up->lcr &= ~UART_LCR_SBC; + serial_out(up, UART_LCR, up->lcr); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static int serial_omap_startup(struct uart_port *port) +@@ -701,13 +701,13 @@ static int serial_omap_startup(struct ua + * Now, initialize the UART + */ + serial_out(up, UART_LCR, UART_LCR_WLEN8); +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + /* + * Most PC uarts need OUT2 raised to enable interrupts. + */ + up->port.mctrl |= TIOCM_OUT2; + serial_omap_set_mctrl(&up->port, up->port.mctrl); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + up->msr_saved_flags = 0; + /* +@@ -742,10 +742,10 @@ static void serial_omap_shutdown(struct + up->ier = 0; + serial_out(up, UART_IER, 0); + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + up->port.mctrl &= ~TIOCM_OUT2; + serial_omap_set_mctrl(&up->port, up->port.mctrl); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + /* + * Disable break condition and FIFOs +@@ -815,7 +815,7 @@ serial_omap_set_termios(struct uart_port + * Ok, we're now changing the port state. Do it with + * interrupts disabled. + */ +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + /* + * Update the per-port timeout. +@@ -1013,7 +1013,7 @@ serial_omap_set_termios(struct uart_port + + serial_omap_set_mctrl(&up->port, up->port.mctrl); + +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + dev_dbg(up->port.dev, "serial_omap_set_termios+%d\n", up->port.line); + } + +@@ -1216,9 +1216,9 @@ serial_omap_console_write(struct console + if (up->port.sysrq) + locked = 0; + else if (oops_in_progress) +- locked = spin_trylock(&up->port.lock); ++ locked = uart_port_trylock(&up->port); + else +- spin_lock(&up->port.lock); ++ uart_port_lock(&up->port); + + /* + * First save the IER then disable the interrupts +@@ -1245,7 +1245,7 @@ serial_omap_console_write(struct console + check_modem_status(up); + + if (locked) +- spin_unlock(&up->port.lock); ++ uart_port_unlock(&up->port); + local_irq_restore(flags); + } + diff --git a/debian/patches-rt/0044-serial-owl-Use-port-lock-wrappers.patch b/debian/patches-rt/0044-serial-owl-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..fd8dc7501 --- /dev/null +++ b/debian/patches-rt/0044-serial-owl-Use-port-lock-wrappers.patch @@ -0,0 +1,147 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:01 +0206 +Subject: [PATCH 044/134] serial: owl: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-45-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/owl-uart.c | 26 +++++++++++++------------- + 1 file changed, 13 insertions(+), 13 deletions(-) + +--- a/drivers/tty/serial/owl-uart.c ++++ b/drivers/tty/serial/owl-uart.c +@@ -125,12 +125,12 @@ static unsigned int owl_uart_tx_empty(st + u32 val; + unsigned int ret; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + val = owl_uart_read(port, OWL_UART_STAT); + ret = (val & OWL_UART_STAT_TFES) ? TIOCSER_TEMT : 0; + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return ret; + } +@@ -232,7 +232,7 @@ static irqreturn_t owl_uart_irq(int irq, + unsigned long flags; + u32 stat; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + stat = owl_uart_read(port, OWL_UART_STAT); + +@@ -246,7 +246,7 @@ static irqreturn_t owl_uart_irq(int irq, + stat |= OWL_UART_STAT_RIP | OWL_UART_STAT_TIP; + owl_uart_write(port, stat, OWL_UART_STAT); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return IRQ_HANDLED; + } +@@ -256,14 +256,14 @@ static void owl_uart_shutdown(struct uar + u32 val; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + val = owl_uart_read(port, OWL_UART_CTL); + val &= ~(OWL_UART_CTL_TXIE | OWL_UART_CTL_RXIE + | OWL_UART_CTL_TXDE | OWL_UART_CTL_RXDE | OWL_UART_CTL_EN); + owl_uart_write(port, val, OWL_UART_CTL); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + free_irq(port->irq, port); + } +@@ -279,7 +279,7 @@ static int owl_uart_startup(struct uart_ + if (ret) + return ret; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + val = owl_uart_read(port, OWL_UART_STAT); + val |= OWL_UART_STAT_RIP | OWL_UART_STAT_TIP +@@ -291,7 +291,7 @@ static int owl_uart_startup(struct uart_ + val |= OWL_UART_CTL_EN; + owl_uart_write(port, val, OWL_UART_CTL); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return 0; + } +@@ -311,7 +311,7 @@ static void owl_uart_set_termios(struct + u32 ctl; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + ctl = owl_uart_read(port, OWL_UART_CTL); + +@@ -371,7 +371,7 @@ static void owl_uart_set_termios(struct + + uart_update_timeout(port, termios->c_cflag, baud); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void owl_uart_release_port(struct uart_port *port) +@@ -515,9 +515,9 @@ static void owl_uart_port_write(struct u + if (port->sysrq) + locked = 0; + else if (oops_in_progress) +- locked = spin_trylock(&port->lock); ++ locked = uart_port_trylock(port); + else { +- spin_lock(&port->lock); ++ uart_port_lock(port); + locked = 1; + } + +@@ -541,7 +541,7 @@ static void owl_uart_port_write(struct u + owl_uart_write(port, old_ctl, OWL_UART_CTL); + + if (locked) +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + local_irq_restore(flags); + } diff --git a/debian/patches-rt/0045-serial-pch-Use-port-lock-wrappers.patch b/debian/patches-rt/0045-serial-pch-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..6c4781cd0 --- /dev/null +++ b/debian/patches-rt/0045-serial-pch-Use-port-lock-wrappers.patch @@ -0,0 +1,80 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:02 +0206 +Subject: [PATCH 045/134] serial: pch: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-46-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/pch_uart.c | 10 +++++----- + 1 file changed, 5 insertions(+), 5 deletions(-) + +--- a/drivers/tty/serial/pch_uart.c ++++ b/drivers/tty/serial/pch_uart.c +@@ -1347,7 +1347,7 @@ static void pch_uart_set_termios(struct + baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16); + + spin_lock_irqsave(&priv->lock, flags); +- spin_lock(&port->lock); ++ uart_port_lock(port); + + uart_update_timeout(port, termios->c_cflag, baud); + rtn = pch_uart_hal_set_line(priv, baud, parity, bits, stb); +@@ -1360,7 +1360,7 @@ static void pch_uart_set_termios(struct + tty_termios_encode_baud_rate(termios, baud, baud); + + out: +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + spin_unlock_irqrestore(&priv->lock, flags); + } + +@@ -1581,10 +1581,10 @@ pch_console_write(struct console *co, co + port_locked = 0; + } else if (oops_in_progress) { + priv_locked = spin_trylock(&priv->lock); +- port_locked = spin_trylock(&priv->port.lock); ++ port_locked = uart_port_trylock(&priv->port); + } else { + spin_lock(&priv->lock); +- spin_lock(&priv->port.lock); ++ uart_port_lock(&priv->port); + } + + /* +@@ -1604,7 +1604,7 @@ pch_console_write(struct console *co, co + iowrite8(ier, priv->membase + UART_IER); + + if (port_locked) +- spin_unlock(&priv->port.lock); ++ uart_port_unlock(&priv->port); + if (priv_locked) + spin_unlock(&priv->lock); + local_irq_restore(flags); diff --git a/debian/patches-rt/0046-serial-pic32-Use-port-lock-wrappers.patch b/debian/patches-rt/0046-serial-pic32-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..7cb8da7d8 --- /dev/null +++ b/debian/patches-rt/0046-serial-pic32-Use-port-lock-wrappers.patch @@ -0,0 +1,118 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:03 +0206 +Subject: [PATCH 046/134] serial: pic32: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-47-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/pic32_uart.c | 20 ++++++++++---------- + 1 file changed, 10 insertions(+), 10 deletions(-) + +--- a/drivers/tty/serial/pic32_uart.c ++++ b/drivers/tty/serial/pic32_uart.c +@@ -243,7 +243,7 @@ static void pic32_uart_break_ctl(struct + struct pic32_sport *sport = to_pic32_sport(port); + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + if (ctl) + pic32_uart_writel(sport, PIC32_SET(PIC32_UART_STA), +@@ -252,7 +252,7 @@ static void pic32_uart_break_ctl(struct + pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_STA), + PIC32_UART_STA_UTXBRK); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /* get port type in string format */ +@@ -274,7 +274,7 @@ static void pic32_uart_do_rx(struct uart + */ + max_count = PIC32_UART_RX_FIFO_DEPTH; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + tty = &port->state->port; + +@@ -331,7 +331,7 @@ static void pic32_uart_do_rx(struct uart + + } while (--max_count); + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + tty_flip_buffer_push(tty); + } +@@ -410,9 +410,9 @@ static irqreturn_t pic32_uart_tx_interru + struct uart_port *port = dev_id; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + pic32_uart_do_tx(port); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return IRQ_HANDLED; + } +@@ -580,9 +580,9 @@ static void pic32_uart_shutdown(struct u + unsigned long flags; + + /* disable uart */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + pic32_uart_dsbl_and_mask(port); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + clk_disable_unprepare(sport->clk); + + /* free all 3 interrupts for this UART */ +@@ -604,7 +604,7 @@ static void pic32_uart_set_termios(struc + unsigned int quot; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* disable uart and mask all interrupts while changing speed */ + pic32_uart_dsbl_and_mask(port); +@@ -672,7 +672,7 @@ static void pic32_uart_set_termios(struc + /* enable uart */ + pic32_uart_en_and_unmask(port); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /* serial core request to claim uart iomem */ diff --git a/debian/patches-rt/0047-serial-pmac_zilog-Use-port-lock-wrappers.patch b/debian/patches-rt/0047-serial-pmac_zilog-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..e4a81157e --- /dev/null +++ b/debian/patches-rt/0047-serial-pmac_zilog-Use-port-lock-wrappers.patch @@ -0,0 +1,232 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:04 +0206 +Subject: [PATCH 047/134] serial: pmac_zilog: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-48-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/pmac_zilog.c | 52 ++++++++++++++++++++-------------------- + 1 file changed, 26 insertions(+), 26 deletions(-) + +--- a/drivers/tty/serial/pmac_zilog.c ++++ b/drivers/tty/serial/pmac_zilog.c +@@ -246,9 +246,9 @@ static bool pmz_receive_chars(struct uar + #endif /* USE_CTRL_O_SYSRQ */ + if (uap->port.sysrq) { + int swallow; +- spin_unlock(&uap->port.lock); ++ uart_port_unlock(&uap->port); + swallow = uart_handle_sysrq_char(&uap->port, ch); +- spin_lock(&uap->port.lock); ++ uart_port_lock(&uap->port); + if (swallow) + goto next_char; + } +@@ -435,7 +435,7 @@ static irqreturn_t pmz_interrupt(int irq + uap_a = pmz_get_port_A(uap); + uap_b = uap_a->mate; + +- spin_lock(&uap_a->port.lock); ++ uart_port_lock(&uap_a->port); + r3 = read_zsreg(uap_a, R3); + + /* Channel A */ +@@ -456,14 +456,14 @@ static irqreturn_t pmz_interrupt(int irq + rc = IRQ_HANDLED; + } + skip_a: +- spin_unlock(&uap_a->port.lock); ++ uart_port_unlock(&uap_a->port); + if (push) + tty_flip_buffer_push(&uap->port.state->port); + + if (!uap_b) + goto out; + +- spin_lock(&uap_b->port.lock); ++ uart_port_lock(&uap_b->port); + push = false; + if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) { + if (!ZS_IS_OPEN(uap_b)) { +@@ -481,7 +481,7 @@ static irqreturn_t pmz_interrupt(int irq + rc = IRQ_HANDLED; + } + skip_b: +- spin_unlock(&uap_b->port.lock); ++ uart_port_unlock(&uap_b->port); + if (push) + tty_flip_buffer_push(&uap->port.state->port); + +@@ -497,9 +497,9 @@ static inline u8 pmz_peek_status(struct + unsigned long flags; + u8 status; + +- spin_lock_irqsave(&uap->port.lock, flags); ++ uart_port_lock_irqsave(&uap->port, &flags); + status = read_zsreg(uap, R0); +- spin_unlock_irqrestore(&uap->port.lock, flags); ++ uart_port_unlock_irqrestore(&uap->port, flags); + + return status; + } +@@ -685,7 +685,7 @@ static void pmz_break_ctl(struct uart_po + else + clear_bits |= SND_BRK; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + new_reg = (uap->curregs[R5] | set_bits) & ~clear_bits; + if (new_reg != uap->curregs[R5]) { +@@ -693,7 +693,7 @@ static void pmz_break_ctl(struct uart_po + write_zsreg(uap, R5, uap->curregs[R5]); + } + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + #ifdef CONFIG_PPC_PMAC +@@ -865,18 +865,18 @@ static void pmz_irda_reset(struct uart_p + { + unsigned long flags; + +- spin_lock_irqsave(&uap->port.lock, flags); ++ uart_port_lock_irqsave(&uap->port, &flags); + uap->curregs[R5] |= DTR; + write_zsreg(uap, R5, uap->curregs[R5]); + zssync(uap); +- spin_unlock_irqrestore(&uap->port.lock, flags); ++ uart_port_unlock_irqrestore(&uap->port, flags); + msleep(110); + +- spin_lock_irqsave(&uap->port.lock, flags); ++ uart_port_lock_irqsave(&uap->port, &flags); + uap->curregs[R5] &= ~DTR; + write_zsreg(uap, R5, uap->curregs[R5]); + zssync(uap); +- spin_unlock_irqrestore(&uap->port.lock, flags); ++ uart_port_unlock_irqrestore(&uap->port, flags); + msleep(10); + } + +@@ -896,9 +896,9 @@ static int pmz_startup(struct uart_port + * initialize the chip + */ + if (!ZS_IS_CONS(uap)) { +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + pwr_delay = __pmz_startup(uap); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + sprintf(uap->irq_name, PMACZILOG_NAME"%d", uap->port.line); + if (request_irq(uap->port.irq, pmz_interrupt, IRQF_SHARED, +@@ -921,9 +921,9 @@ static int pmz_startup(struct uart_port + pmz_irda_reset(uap); + + /* Enable interrupt requests for the channel */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + pmz_interrupt_control(uap, 1); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return 0; + } +@@ -933,7 +933,7 @@ static void pmz_shutdown(struct uart_por + struct uart_pmac_port *uap = to_pmz(port); + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Disable interrupt requests for the channel */ + pmz_interrupt_control(uap, 0); +@@ -948,19 +948,19 @@ static void pmz_shutdown(struct uart_por + pmz_maybe_update_regs(uap); + } + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + /* Release interrupt handler */ + free_irq(uap->port.irq, uap); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + uap->flags &= ~PMACZILOG_FLAG_IS_OPEN; + + if (!ZS_IS_CONS(uap)) + pmz_set_scc_power(uap, 0); /* Shut the chip down */ + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /* Shared by TTY driver and serial console setup. The port lock is held +@@ -1247,7 +1247,7 @@ static void pmz_set_termios(struct uart_ + struct uart_pmac_port *uap = to_pmz(port); + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Disable IRQs on the port */ + pmz_interrupt_control(uap, 0); +@@ -1259,7 +1259,7 @@ static void pmz_set_termios(struct uart_ + if (ZS_IS_OPEN(uap)) + pmz_interrupt_control(uap, 1); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *pmz_type(struct uart_port *port) +@@ -1896,7 +1896,7 @@ static void pmz_console_write(struct con + struct uart_pmac_port *uap = &pmz_ports[con->index]; + unsigned long flags; + +- spin_lock_irqsave(&uap->port.lock, flags); ++ uart_port_lock_irqsave(&uap->port, &flags); + + /* Turn of interrupts and enable the transmitter. */ + write_zsreg(uap, R1, uap->curregs[1] & ~TxINT_ENAB); +@@ -1908,7 +1908,7 @@ static void pmz_console_write(struct con + write_zsreg(uap, R1, uap->curregs[1]); + /* Don't disable the transmitter. */ + +- spin_unlock_irqrestore(&uap->port.lock, flags); ++ uart_port_unlock_irqrestore(&uap->port, flags); + } + + /* diff --git a/debian/patches-rt/0048-serial-pxa-Use-port-lock-wrappers.patch b/debian/patches-rt/0048-serial-pxa-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..b0df211b6 --- /dev/null +++ b/debian/patches-rt/0048-serial-pxa-Use-port-lock-wrappers.patch @@ -0,0 +1,150 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:05 +0206 +Subject: [PATCH 048/134] serial: pxa: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-49-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/pxa.c | 30 +++++++++++++++--------------- + 1 file changed, 15 insertions(+), 15 deletions(-) + +--- a/drivers/tty/serial/pxa.c ++++ b/drivers/tty/serial/pxa.c +@@ -225,14 +225,14 @@ static inline irqreturn_t serial_pxa_irq + iir = serial_in(up, UART_IIR); + if (iir & UART_IIR_NO_INT) + return IRQ_NONE; +- spin_lock(&up->port.lock); ++ uart_port_lock(&up->port); + lsr = serial_in(up, UART_LSR); + if (lsr & UART_LSR_DR) + receive_chars(up, &lsr); + check_modem_status(up); + if (lsr & UART_LSR_THRE) + transmit_chars(up); +- spin_unlock(&up->port.lock); ++ uart_port_unlock(&up->port); + return IRQ_HANDLED; + } + +@@ -242,9 +242,9 @@ static unsigned int serial_pxa_tx_empty( + unsigned long flags; + unsigned int ret; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0; +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + return ret; + } +@@ -295,13 +295,13 @@ static void serial_pxa_break_ctl(struct + struct uart_pxa_port *up = (struct uart_pxa_port *)port; + unsigned long flags; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + if (break_state == -1) + up->lcr |= UART_LCR_SBC; + else + up->lcr &= ~UART_LCR_SBC; + serial_out(up, UART_LCR, up->lcr); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static int serial_pxa_startup(struct uart_port *port) +@@ -346,10 +346,10 @@ static int serial_pxa_startup(struct uar + */ + serial_out(up, UART_LCR, UART_LCR_WLEN8); + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + up->port.mctrl |= TIOCM_OUT2; + serial_pxa_set_mctrl(&up->port, up->port.mctrl); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + /* + * Finally, enable interrupts. Note: Modem status interrupts +@@ -383,10 +383,10 @@ static void serial_pxa_shutdown(struct u + up->ier = 0; + serial_out(up, UART_IER, 0); + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + up->port.mctrl &= ~TIOCM_OUT2; + serial_pxa_set_mctrl(&up->port, up->port.mctrl); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + /* + * Disable break condition and FIFOs +@@ -434,7 +434,7 @@ serial_pxa_set_termios(struct uart_port + * Ok, we're now changing the port state. Do it with + * interrupts disabled. + */ +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + /* + * Ensure the port will be enabled. +@@ -504,7 +504,7 @@ serial_pxa_set_termios(struct uart_port + up->lcr = cval; /* Save LCR */ + serial_pxa_set_mctrl(&up->port, up->port.mctrl); + serial_out(up, UART_FCR, fcr); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static void +@@ -608,9 +608,9 @@ serial_pxa_console_write(struct console + if (up->port.sysrq) + locked = 0; + else if (oops_in_progress) +- locked = spin_trylock(&up->port.lock); ++ locked = uart_port_trylock(&up->port); + else +- spin_lock(&up->port.lock); ++ uart_port_lock(&up->port); + + /* + * First save the IER then disable the interrupts +@@ -628,7 +628,7 @@ serial_pxa_console_write(struct console + serial_out(up, UART_IER, ier); + + if (locked) +- spin_unlock(&up->port.lock); ++ uart_port_unlock(&up->port); + local_irq_restore(flags); + clk_disable(up->clk); + diff --git a/debian/patches-rt/0049-serial-qcom-geni-Use-port-lock-wrappers.patch b/debian/patches-rt/0049-serial-qcom-geni-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..4f1bc6a1c --- /dev/null +++ b/debian/patches-rt/0049-serial-qcom-geni-Use-port-lock-wrappers.patch @@ -0,0 +1,71 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:06 +0206 +Subject: [PATCH 049/134] serial: qcom-geni: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Reviewed-by: Bjorn Andersson +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-50-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/qcom_geni_serial.c | 8 ++++---- + 1 file changed, 4 insertions(+), 4 deletions(-) + +--- a/drivers/tty/serial/qcom_geni_serial.c ++++ b/drivers/tty/serial/qcom_geni_serial.c +@@ -482,9 +482,9 @@ static void qcom_geni_serial_console_wri + + uport = &port->uport; + if (oops_in_progress) +- locked = spin_trylock_irqsave(&uport->lock, flags); ++ locked = uart_port_trylock_irqsave(uport, &flags); + else +- spin_lock_irqsave(&uport->lock, flags); ++ uart_port_lock_irqsave(uport, &flags); + + geni_status = readl(uport->membase + SE_GENI_STATUS); + +@@ -520,7 +520,7 @@ static void qcom_geni_serial_console_wri + qcom_geni_serial_setup_tx(uport, port->tx_remaining); + + if (locked) +- spin_unlock_irqrestore(&uport->lock, flags); ++ uart_port_unlock_irqrestore(uport, flags); + } + + static void handle_rx_console(struct uart_port *uport, u32 bytes, bool drop) +@@ -970,7 +970,7 @@ static irqreturn_t qcom_geni_serial_isr( + if (uport->suspended) + return IRQ_NONE; + +- spin_lock(&uport->lock); ++ uart_port_lock(uport); + + m_irq_status = readl(uport->membase + SE_GENI_M_IRQ_STATUS); + s_irq_status = readl(uport->membase + SE_GENI_S_IRQ_STATUS); diff --git a/debian/patches-rt/0050-serial-rda-Use-port-lock-wrappers.patch b/debian/patches-rt/0050-serial-rda-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..6d51972bc --- /dev/null +++ b/debian/patches-rt/0050-serial-rda-Use-port-lock-wrappers.patch @@ -0,0 +1,177 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:07 +0206 +Subject: [PATCH 050/134] serial: rda: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-51-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/rda-uart.c | 34 +++++++++++++++++----------------- + 1 file changed, 17 insertions(+), 17 deletions(-) + +--- a/drivers/tty/serial/rda-uart.c ++++ b/drivers/tty/serial/rda-uart.c +@@ -139,12 +139,12 @@ static unsigned int rda_uart_tx_empty(st + unsigned int ret; + u32 val; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + val = rda_uart_read(port, RDA_UART_STATUS); + ret = (val & RDA_UART_TX_FIFO_MASK) ? TIOCSER_TEMT : 0; + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return ret; + } +@@ -246,7 +246,7 @@ static void rda_uart_set_termios(struct + unsigned int baud; + u32 irq_mask; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + baud = uart_get_baud_rate(port, termios, old, 9600, port->uartclk / 4); + rda_uart_change_baudrate(rda_port, baud); +@@ -325,7 +325,7 @@ static void rda_uart_set_termios(struct + /* update the per-port timeout */ + uart_update_timeout(port, termios->c_cflag, baud); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void rda_uart_send_chars(struct uart_port *port) +@@ -408,7 +408,7 @@ static irqreturn_t rda_interrupt(int irq + unsigned long flags; + u32 val, irq_mask; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Clear IRQ cause */ + val = rda_uart_read(port, RDA_UART_IRQ_CAUSE); +@@ -425,7 +425,7 @@ static irqreturn_t rda_interrupt(int irq + rda_uart_send_chars(port); + } + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return IRQ_HANDLED; + } +@@ -436,16 +436,16 @@ static int rda_uart_startup(struct uart_ + int ret; + u32 val; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + rda_uart_write(port, 0, RDA_UART_IRQ_MASK); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + ret = request_irq(port->irq, rda_interrupt, IRQF_NO_SUSPEND, + "rda-uart", port); + if (ret) + return ret; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + val = rda_uart_read(port, RDA_UART_CTRL); + val |= RDA_UART_ENABLE; +@@ -456,7 +456,7 @@ static int rda_uart_startup(struct uart_ + val |= (RDA_UART_RX_DATA_AVAILABLE | RDA_UART_RX_TIMEOUT); + rda_uart_write(port, val, RDA_UART_IRQ_MASK); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return 0; + } +@@ -466,7 +466,7 @@ static void rda_uart_shutdown(struct uar + unsigned long flags; + u32 val; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + rda_uart_stop_tx(port); + rda_uart_stop_rx(port); +@@ -475,7 +475,7 @@ static void rda_uart_shutdown(struct uar + val &= ~RDA_UART_ENABLE; + rda_uart_write(port, val, RDA_UART_CTRL); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *rda_uart_type(struct uart_port *port) +@@ -515,7 +515,7 @@ static void rda_uart_config_port(struct + rda_uart_request_port(port); + } + +- spin_lock_irqsave(&port->lock, irq_flags); ++ uart_port_lock_irqsave(port, &irq_flags); + + /* Clear mask, so no surprise interrupts. */ + rda_uart_write(port, 0, RDA_UART_IRQ_MASK); +@@ -523,7 +523,7 @@ static void rda_uart_config_port(struct + /* Clear status register */ + rda_uart_write(port, 0, RDA_UART_STATUS); + +- spin_unlock_irqrestore(&port->lock, irq_flags); ++ uart_port_unlock_irqrestore(port, irq_flags); + } + + static void rda_uart_release_port(struct uart_port *port) +@@ -597,9 +597,9 @@ static void rda_uart_port_write(struct u + if (port->sysrq) { + locked = 0; + } else if (oops_in_progress) { +- locked = spin_trylock(&port->lock); ++ locked = uart_port_trylock(port); + } else { +- spin_lock(&port->lock); ++ uart_port_lock(port); + locked = 1; + } + +@@ -615,7 +615,7 @@ static void rda_uart_port_write(struct u + rda_uart_write(port, old_irq_mask, RDA_UART_IRQ_MASK); + + if (locked) +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + local_irq_restore(flags); + } diff --git a/debian/patches-rt/0051-serial-rp2-Use-port-lock-wrappers.patch b/debian/patches-rt/0051-serial-rp2-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..e2009ff4c --- /dev/null +++ b/debian/patches-rt/0051-serial-rp2-Use-port-lock-wrappers.patch @@ -0,0 +1,114 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:08 +0206 +Subject: [PATCH 051/134] serial: rp2: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-52-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/rp2.c | 20 ++++++++++---------- + 1 file changed, 10 insertions(+), 10 deletions(-) + +--- a/drivers/tty/serial/rp2.c ++++ b/drivers/tty/serial/rp2.c +@@ -276,9 +276,9 @@ static unsigned int rp2_uart_tx_empty(st + * But the TXEMPTY bit doesn't seem to work unless the TX IRQ is + * enabled. + */ +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + tx_fifo_bytes = readw(up->base + RP2_TX_FIFO_COUNT); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + return tx_fifo_bytes ? 0 : TIOCSER_TEMT; + } +@@ -323,10 +323,10 @@ static void rp2_uart_break_ctl(struct ua + { + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + rp2_rmw(port_to_up(port), RP2_TXRX_CTL, RP2_TXRX_CTL_BREAK_m, + break_state ? RP2_TXRX_CTL_BREAK_m : 0); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void rp2_uart_enable_ms(struct uart_port *port) +@@ -383,7 +383,7 @@ static void rp2_uart_set_termios(struct + if (tty_termios_baud_rate(new)) + tty_termios_encode_baud_rate(new, baud, baud); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* ignore all characters if CREAD is not set */ + port->ignore_status_mask = (new->c_cflag & CREAD) ? 0 : RP2_DUMMY_READ; +@@ -391,7 +391,7 @@ static void rp2_uart_set_termios(struct + __rp2_uart_set_termios(up, new->c_cflag, new->c_iflag, baud_div); + uart_update_timeout(port, new->c_cflag, baud); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void rp2_rx_chars(struct rp2_uart_port *up) +@@ -440,7 +440,7 @@ static void rp2_ch_interrupt(struct rp2_ + { + u32 status; + +- spin_lock(&up->port.lock); ++ uart_port_lock(&up->port); + + /* + * The IRQ status bits are clear-on-write. Other status bits in +@@ -456,7 +456,7 @@ static void rp2_ch_interrupt(struct rp2_ + if (status & RP2_CHAN_STAT_MS_CHANGED_MASK) + wake_up_interruptible(&up->port.state->port.delta_msr_wait); + +- spin_unlock(&up->port.lock); ++ uart_port_unlock(&up->port); + } + + static int rp2_asic_interrupt(struct rp2_card *card, unsigned int asic_id) +@@ -516,10 +516,10 @@ static void rp2_uart_shutdown(struct uar + + rp2_uart_break_ctl(port, 0); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + rp2_mask_ch_irq(up, up->idx, 0); + rp2_rmw(up, RP2_CHAN_STAT, 0, 0); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *rp2_uart_type(struct uart_port *port) diff --git a/debian/patches-rt/0052-serial-sa1100-Use-port-lock-wrappers.patch b/debian/patches-rt/0052-serial-sa1100-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..2f8073a48 --- /dev/null +++ b/debian/patches-rt/0052-serial-sa1100-Use-port-lock-wrappers.patch @@ -0,0 +1,117 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:09 +0206 +Subject: [PATCH 052/134] serial: sa1100: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-53-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/sa1100.c | 20 ++++++++++---------- + 1 file changed, 10 insertions(+), 10 deletions(-) + +--- a/drivers/tty/serial/sa1100.c ++++ b/drivers/tty/serial/sa1100.c +@@ -115,9 +115,9 @@ static void sa1100_timeout(struct timer_ + unsigned long flags; + + if (sport->port.state) { +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + sa1100_mctrl_check(sport); +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + + mod_timer(&sport->timer, jiffies + MCTRL_TIMEOUT); + } +@@ -247,7 +247,7 @@ static irqreturn_t sa1100_int(int irq, v + struct sa1100_port *sport = dev_id; + unsigned int status, pass_counter = 0; + +- spin_lock(&sport->port.lock); ++ uart_port_lock(&sport->port); + status = UART_GET_UTSR0(sport); + status &= SM_TO_UTSR0(sport->port.read_status_mask) | ~UTSR0_TFS; + do { +@@ -276,7 +276,7 @@ static irqreturn_t sa1100_int(int irq, v + status &= SM_TO_UTSR0(sport->port.read_status_mask) | + ~UTSR0_TFS; + } while (status & (UTSR0_TFS | UTSR0_RFS | UTSR0_RID)); +- spin_unlock(&sport->port.lock); ++ uart_port_unlock(&sport->port); + + return IRQ_HANDLED; + } +@@ -321,14 +321,14 @@ static void sa1100_break_ctl(struct uart + unsigned long flags; + unsigned int utcr3; + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + utcr3 = UART_GET_UTCR3(sport); + if (break_state == -1) + utcr3 |= UTCR3_BRK; + else + utcr3 &= ~UTCR3_BRK; + UART_PUT_UTCR3(sport, utcr3); +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + } + + static int sa1100_startup(struct uart_port *port) +@@ -354,9 +354,9 @@ static int sa1100_startup(struct uart_po + /* + * Enable modem status interrupts + */ +- spin_lock_irq(&sport->port.lock); ++ uart_port_lock_irq(&sport->port); + sa1100_enable_ms(&sport->port); +- spin_unlock_irq(&sport->port.lock); ++ uart_port_unlock_irq(&sport->port); + + return 0; + } +@@ -423,7 +423,7 @@ sa1100_set_termios(struct uart_port *por + + del_timer_sync(&sport->timer); + +- spin_lock_irqsave(&sport->port.lock, flags); ++ uart_port_lock_irqsave(&sport->port, &flags); + + sport->port.read_status_mask &= UTSR0_TO_SM(UTSR0_TFS); + sport->port.read_status_mask |= UTSR1_TO_SM(UTSR1_ROR); +@@ -485,7 +485,7 @@ sa1100_set_termios(struct uart_port *por + if (UART_ENABLE_MS(&sport->port, termios->c_cflag)) + sa1100_enable_ms(&sport->port); + +- spin_unlock_irqrestore(&sport->port.lock, flags); ++ uart_port_unlock_irqrestore(&sport->port, flags); + } + + static const char *sa1100_type(struct uart_port *port) diff --git a/debian/patches-rt/0053-serial-samsung_tty-Use-port-lock-wrappers.patch b/debian/patches-rt/0053-serial-samsung_tty-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..74dc3c014 --- /dev/null +++ b/debian/patches-rt/0053-serial-samsung_tty-Use-port-lock-wrappers.patch @@ -0,0 +1,245 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:10 +0206 +Subject: [PATCH 053/134] serial: samsung_tty: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-54-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/samsung_tty.c | 50 +++++++++++++++++++-------------------- + 1 file changed, 25 insertions(+), 25 deletions(-) + +--- a/drivers/tty/serial/samsung_tty.c ++++ b/drivers/tty/serial/samsung_tty.c +@@ -248,7 +248,7 @@ static void s3c24xx_serial_rx_enable(str + unsigned int ucon, ufcon; + int count = 10000; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + while (--count && !s3c24xx_serial_txempty_nofifo(port)) + udelay(100); +@@ -262,7 +262,7 @@ static void s3c24xx_serial_rx_enable(str + wr_regl(port, S3C2410_UCON, ucon); + + ourport->rx_enabled = 1; +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void s3c24xx_serial_rx_disable(struct uart_port *port) +@@ -271,14 +271,14 @@ static void s3c24xx_serial_rx_disable(st + unsigned long flags; + unsigned int ucon; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + ucon = rd_regl(port, S3C2410_UCON); + ucon &= ~S3C2410_UCON_RXIRQMODE; + wr_regl(port, S3C2410_UCON, ucon); + + ourport->rx_enabled = 0; +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void s3c24xx_serial_stop_tx(struct uart_port *port) +@@ -344,7 +344,7 @@ static void s3c24xx_serial_tx_dma_comple + dma->tx_transfer_addr, dma->tx_size, + DMA_TO_DEVICE); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + uart_xmit_advance(port, count); + ourport->tx_in_progress = 0; +@@ -353,7 +353,7 @@ static void s3c24xx_serial_tx_dma_comple + uart_write_wakeup(port); + + s3c24xx_serial_start_next_tx(ourport); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void enable_tx_dma(struct s3c24xx_uart_port *ourport) +@@ -619,7 +619,7 @@ static void s3c24xx_serial_rx_dma_comple + received = dma->rx_bytes_requested - state.residue; + async_tx_ack(dma->rx_desc); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + if (received) + s3c24xx_uart_copy_rx_to_tty(ourport, t, received); +@@ -631,7 +631,7 @@ static void s3c24xx_serial_rx_dma_comple + + s3c64xx_start_rx_dma(ourport); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void s3c64xx_start_rx_dma(struct s3c24xx_uart_port *ourport) +@@ -722,7 +722,7 @@ static irqreturn_t s3c24xx_serial_rx_cha + utrstat = rd_regl(port, S3C2410_UTRSTAT); + rd_regl(port, S3C2410_UFSTAT); + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + if (!(utrstat & S3C2410_UTRSTAT_TIMEOUT)) { + s3c64xx_start_rx_dma(ourport); +@@ -751,7 +751,7 @@ static irqreturn_t s3c24xx_serial_rx_cha + wr_regl(port, S3C2410_UTRSTAT, S3C2410_UTRSTAT_TIMEOUT); + + finish: +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return IRQ_HANDLED; + } +@@ -849,9 +849,9 @@ static irqreturn_t s3c24xx_serial_rx_cha + struct s3c24xx_uart_port *ourport = dev_id; + struct uart_port *port = &ourport->port; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + s3c24xx_serial_rx_drain_fifo(ourport); +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return IRQ_HANDLED; + } +@@ -932,11 +932,11 @@ static irqreturn_t s3c24xx_serial_tx_irq + struct s3c24xx_uart_port *ourport = id; + struct uart_port *port = &ourport->port; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + s3c24xx_serial_tx_chars(ourport); + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + return IRQ_HANDLED; + } + +@@ -1033,7 +1033,7 @@ static void s3c24xx_serial_break_ctl(str + unsigned long flags; + unsigned int ucon; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + ucon = rd_regl(port, S3C2410_UCON); + +@@ -1044,7 +1044,7 @@ static void s3c24xx_serial_break_ctl(str + + wr_regl(port, S3C2410_UCON, ucon); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p) +@@ -1303,7 +1303,7 @@ static int s3c64xx_serial_startup(struct + ourport->rx_enabled = 1; + ourport->tx_enabled = 0; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + ufcon = rd_regl(port, S3C2410_UFCON); + ufcon |= S3C2410_UFCON_RESETRX | S5PV210_UFCON_RXTRIG8; +@@ -1313,7 +1313,7 @@ static int s3c64xx_serial_startup(struct + + enable_rx_pio(ourport); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + /* Enable Rx Interrupt */ + s3c24xx_clear_bit(port, S3C64XX_UINTM_RXD, S3C64XX_UINTM); +@@ -1341,7 +1341,7 @@ static int apple_s5l_serial_startup(stru + ourport->rx_enabled = 1; + ourport->tx_enabled = 0; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + ufcon = rd_regl(port, S3C2410_UFCON); + ufcon |= S3C2410_UFCON_RESETRX | S5PV210_UFCON_RXTRIG8; +@@ -1351,7 +1351,7 @@ static int apple_s5l_serial_startup(stru + + enable_rx_pio(ourport); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + /* Enable Rx Interrupt */ + s3c24xx_set_bit(port, APPLE_S5L_UCON_RXTHRESH_ENA, S3C2410_UCON); +@@ -1626,7 +1626,7 @@ static void s3c24xx_serial_set_termios(s + ulcon |= S3C2410_LCON_PNONE; + } + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + dev_dbg(port->dev, + "setting ulcon to %08x, brddiv to %d, udivslot %08x\n", +@@ -1684,7 +1684,7 @@ static void s3c24xx_serial_set_termios(s + if ((termios->c_cflag & CREAD) == 0) + port->ignore_status_mask |= RXSTAT_DUMMY_READ; + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *s3c24xx_serial_type(struct uart_port *port) +@@ -2376,14 +2376,14 @@ s3c24xx_serial_console_write(struct cons + if (cons_uart->sysrq) + locked = false; + else if (oops_in_progress) +- locked = spin_trylock_irqsave(&cons_uart->lock, flags); ++ locked = uart_port_trylock_irqsave(cons_uart, &flags); + else +- spin_lock_irqsave(&cons_uart->lock, flags); ++ uart_port_lock_irqsave(cons_uart, &flags); + + uart_console_write(cons_uart, s, count, s3c24xx_serial_console_putchar); + + if (locked) +- spin_unlock_irqrestore(&cons_uart->lock, flags); ++ uart_port_unlock_irqrestore(cons_uart, flags); + } + + /* Shouldn't be __init, as it can be instantiated from other module */ diff --git a/debian/patches-rt/0054-serial-sb1250-duart-Use-port-lock-wrappers.patch b/debian/patches-rt/0054-serial-sb1250-duart-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..e5aeb528f --- /dev/null +++ b/debian/patches-rt/0054-serial-sb1250-duart-Use-port-lock-wrappers.patch @@ -0,0 +1,85 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:11 +0206 +Subject: [PATCH 054/134] serial: sb1250-duart: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-55-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/sb1250-duart.c | 12 ++++++------ + 1 file changed, 6 insertions(+), 6 deletions(-) + +--- a/drivers/tty/serial/sb1250-duart.c ++++ b/drivers/tty/serial/sb1250-duart.c +@@ -610,7 +610,7 @@ static void sbd_set_termios(struct uart_ + else + aux &= ~M_DUART_CTS_CHNG_ENA; + +- spin_lock(&uport->lock); ++ uart_port_lock(uport); + + if (sport->tx_stopped) + command |= M_DUART_TX_DIS; +@@ -632,7 +632,7 @@ static void sbd_set_termios(struct uart_ + + write_sbdchn(sport, R_DUART_CMD, command); + +- spin_unlock(&uport->lock); ++ uart_port_unlock(uport); + } + + +@@ -839,22 +839,22 @@ static void sbd_console_write(struct con + unsigned int mask; + + /* Disable transmit interrupts and enable the transmitter. */ +- spin_lock_irqsave(&uport->lock, flags); ++ uart_port_lock_irqsave(uport, &flags); + mask = read_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2)); + write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2), + mask & ~M_DUART_IMR_TX); + write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_EN); +- spin_unlock_irqrestore(&uport->lock, flags); ++ uart_port_unlock_irqrestore(uport, flags); + + uart_console_write(&sport->port, s, count, sbd_console_putchar); + + /* Restore transmit interrupts and the transmitter enable. */ +- spin_lock_irqsave(&uport->lock, flags); ++ uart_port_lock_irqsave(uport, &flags); + sbd_line_drain(sport); + if (sport->tx_stopped) + write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_DIS); + write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2), mask); +- spin_unlock_irqrestore(&uport->lock, flags); ++ uart_port_unlock_irqrestore(uport, flags); + } + + static int __init sbd_console_setup(struct console *co, char *options) diff --git a/debian/patches-rt/0056-serial-tegra-Use-port-lock-wrappers.patch b/debian/patches-rt/0056-serial-tegra-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..f53b521dc --- /dev/null +++ b/debian/patches-rt/0056-serial-tegra-Use-port-lock-wrappers.patch @@ -0,0 +1,176 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:13 +0206 +Subject: [PATCH 056/134] serial: tegra: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-57-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/serial-tegra.c | 32 ++++++++++++++++---------------- + 1 file changed, 16 insertions(+), 16 deletions(-) + +--- a/drivers/tty/serial/serial-tegra.c ++++ b/drivers/tty/serial/serial-tegra.c +@@ -411,7 +411,7 @@ static int tegra_set_baudrate(struct teg + divisor = DIV_ROUND_CLOSEST(rate, baud * 16); + } + +- spin_lock_irqsave(&tup->uport.lock, flags); ++ uart_port_lock_irqsave(&tup->uport, &flags); + lcr = tup->lcr_shadow; + lcr |= UART_LCR_DLAB; + tegra_uart_write(tup, lcr, UART_LCR); +@@ -424,7 +424,7 @@ static int tegra_set_baudrate(struct teg + + /* Dummy read to ensure the write is posted */ + tegra_uart_read(tup, UART_SCR); +- spin_unlock_irqrestore(&tup->uport.lock, flags); ++ uart_port_unlock_irqrestore(&tup->uport, flags); + + tup->current_baud = baud; + +@@ -522,13 +522,13 @@ static void tegra_uart_tx_dma_complete(v + dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state); + count = tup->tx_bytes_requested - state.residue; + async_tx_ack(tup->tx_dma_desc); +- spin_lock_irqsave(&tup->uport.lock, flags); ++ uart_port_lock_irqsave(&tup->uport, &flags); + uart_xmit_advance(&tup->uport, count); + tup->tx_in_progress = 0; + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + uart_write_wakeup(&tup->uport); + tegra_uart_start_next_tx(tup); +- spin_unlock_irqrestore(&tup->uport.lock, flags); ++ uart_port_unlock_irqrestore(&tup->uport, flags); + } + + static int tegra_uart_start_tx_dma(struct tegra_uart_port *tup, +@@ -598,13 +598,13 @@ static unsigned int tegra_uart_tx_empty( + unsigned int ret = 0; + unsigned long flags; + +- spin_lock_irqsave(&u->lock, flags); ++ uart_port_lock_irqsave(u, &flags); + if (!tup->tx_in_progress) { + unsigned long lsr = tegra_uart_read(tup, UART_LSR); + if ((lsr & TX_EMPTY_STATUS) == TX_EMPTY_STATUS) + ret = TIOCSER_TEMT; + } +- spin_unlock_irqrestore(&u->lock, flags); ++ uart_port_unlock_irqrestore(u, flags); + return ret; + } + +@@ -727,7 +727,7 @@ static void tegra_uart_rx_dma_complete(v + struct dma_tx_state state; + enum dma_status status; + +- spin_lock_irqsave(&u->lock, flags); ++ uart_port_lock_irqsave(u, &flags); + + status = dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state); + +@@ -749,7 +749,7 @@ static void tegra_uart_rx_dma_complete(v + set_rts(tup, true); + + done: +- spin_unlock_irqrestore(&u->lock, flags); ++ uart_port_unlock_irqrestore(u, flags); + } + + static void tegra_uart_terminate_rx_dma(struct tegra_uart_port *tup) +@@ -836,7 +836,7 @@ static irqreturn_t tegra_uart_isr(int ir + bool is_rx_int = false; + unsigned long flags; + +- spin_lock_irqsave(&u->lock, flags); ++ uart_port_lock_irqsave(u, &flags); + while (1) { + iir = tegra_uart_read(tup, UART_IIR); + if (iir & UART_IIR_NO_INT) { +@@ -852,7 +852,7 @@ static irqreturn_t tegra_uart_isr(int ir + } else if (is_rx_start) { + tegra_uart_start_rx_dma(tup); + } +- spin_unlock_irqrestore(&u->lock, flags); ++ uart_port_unlock_irqrestore(u, flags); + return IRQ_HANDLED; + } + +@@ -969,11 +969,11 @@ static void tegra_uart_hw_deinit(struct + } + } + +- spin_lock_irqsave(&tup->uport.lock, flags); ++ uart_port_lock_irqsave(&tup->uport, &flags); + /* Reset the Rx and Tx FIFOs */ + tegra_uart_fifo_reset(tup, UART_FCR_CLEAR_XMIT | UART_FCR_CLEAR_RCVR); + tup->current_baud = 0; +- spin_unlock_irqrestore(&tup->uport.lock, flags); ++ uart_port_unlock_irqrestore(&tup->uport, flags); + + tup->rx_in_progress = 0; + tup->tx_in_progress = 0; +@@ -1292,7 +1292,7 @@ static void tegra_uart_set_termios(struc + int ret; + + max_divider *= 16; +- spin_lock_irqsave(&u->lock, flags); ++ uart_port_lock_irqsave(u, &flags); + + /* Changing configuration, it is safe to stop any rx now */ + if (tup->rts_active) +@@ -1341,7 +1341,7 @@ static void tegra_uart_set_termios(struc + baud = uart_get_baud_rate(u, termios, oldtermios, + parent_clk_rate/max_divider, + parent_clk_rate/16); +- spin_unlock_irqrestore(&u->lock, flags); ++ uart_port_unlock_irqrestore(u, flags); + ret = tegra_set_baudrate(tup, baud); + if (ret < 0) { + dev_err(tup->uport.dev, "Failed to set baud rate\n"); +@@ -1349,7 +1349,7 @@ static void tegra_uart_set_termios(struc + } + if (tty_termios_baud_rate(termios)) + tty_termios_encode_baud_rate(termios, baud, baud); +- spin_lock_irqsave(&u->lock, flags); ++ uart_port_lock_irqsave(u, &flags); + + /* Flow control */ + if (termios->c_cflag & CRTSCTS) { +@@ -1382,7 +1382,7 @@ static void tegra_uart_set_termios(struc + if (termios->c_iflag & IGNBRK) + tup->uport.ignore_status_mask |= UART_LSR_BI; + +- spin_unlock_irqrestore(&u->lock, flags); ++ uart_port_unlock_irqrestore(u, flags); + } + + static const char *tegra_uart_type(struct uart_port *u) diff --git a/debian/patches-rt/0057-serial-core-Use-port-lock-wrappers.patch b/debian/patches-rt/0057-serial-core-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..33c270382 --- /dev/null +++ b/debian/patches-rt/0057-serial-core-Use-port-lock-wrappers.patch @@ -0,0 +1,365 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:14 +0206 +Subject: [PATCH 057/134] serial: core: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-58-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/serial_core.c | 92 +++++++++++++++++++-------------------- + drivers/tty/serial/serial_port.c | 4 - + 2 files changed, 48 insertions(+), 48 deletions(-) + +--- a/drivers/tty/serial/serial_core.c ++++ b/drivers/tty/serial/serial_core.c +@@ -79,7 +79,7 @@ + ({ \ + struct uart_port *__uport = uart_port_ref(state); \ + if (__uport) \ +- spin_lock_irqsave(&__uport->lock, flags); \ ++ uart_port_lock_irqsave(__uport, &flags); \ + __uport; \ + }) + +@@ -87,7 +87,7 @@ + ({ \ + struct uart_port *__uport = uport; \ + if (__uport) { \ +- spin_unlock_irqrestore(&__uport->lock, flags); \ ++ uart_port_unlock_irqrestore(__uport, flags); \ + uart_port_deref(__uport); \ + } \ + }) +@@ -179,12 +179,12 @@ + unsigned long flags; + unsigned int old; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + old = port->mctrl; + port->mctrl = (old & ~clear) | set; + if (old != port->mctrl && !(port->rs485.flags & SER_RS485_ENABLED)) + port->ops->set_mctrl(port, port->mctrl); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + #define uart_set_mctrl(port, set) uart_update_mctrl(port, set, 0) +@@ -219,7 +219,7 @@ + /* + * Set modem status enables based on termios cflag + */ +- spin_lock_irq(&uport->lock); ++ uart_port_lock_irq(uport); + if (termios->c_cflag & CRTSCTS) + uport->status |= UPSTAT_CTS_ENABLE; + else +@@ -240,7 +240,7 @@ + else + __uart_start(state); + } +- spin_unlock_irq(&uport->lock); ++ uart_port_unlock_irq(uport); + } + + /* +@@ -702,11 +702,11 @@ + if (port->ops->send_xchar) + port->ops->send_xchar(port, ch); + else { +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + port->x_char = ch; + if (ch) + port->ops->start_tx(port); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + uart_port_deref(port); + } +@@ -1085,9 +1085,9 @@ + + if (!tty_io_error(tty)) { + result = uport->mctrl; +- spin_lock_irq(&uport->lock); ++ uart_port_lock_irq(uport); + result |= uport->ops->get_mctrl(uport); +- spin_unlock_irq(&uport->lock); ++ uart_port_unlock_irq(uport); + } + out: + mutex_unlock(&port->mutex); +@@ -1223,16 +1223,16 @@ + uport = uart_port_ref(state); + if (!uport) + return -EIO; +- spin_lock_irq(&uport->lock); ++ uart_port_lock_irq(uport); + memcpy(&cprev, &uport->icount, sizeof(struct uart_icount)); + uart_enable_ms(uport); +- spin_unlock_irq(&uport->lock); ++ uart_port_unlock_irq(uport); + + add_wait_queue(&port->delta_msr_wait, &wait); + for (;;) { +- spin_lock_irq(&uport->lock); ++ uart_port_lock_irq(uport); + memcpy(&cnow, &uport->icount, sizeof(struct uart_icount)); +- spin_unlock_irq(&uport->lock); ++ uart_port_unlock_irq(uport); + + set_current_state(TASK_INTERRUPTIBLE); + +@@ -1277,9 +1277,9 @@ + uport = uart_port_ref(state); + if (!uport) + return -EIO; +- spin_lock_irq(&uport->lock); ++ uart_port_lock_irq(uport); + memcpy(&cnow, &uport->icount, sizeof(struct uart_icount)); +- spin_unlock_irq(&uport->lock); ++ uart_port_unlock_irq(uport); + uart_port_deref(uport); + + icount->cts = cnow.cts; +@@ -1432,9 +1432,9 @@ + uart_set_rs485_termination(port, rs485); + uart_set_rs485_rx_during_tx(port, rs485); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + ret = port->rs485_config(port, NULL, rs485); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + if (ret) { + memset(rs485, 0, sizeof(*rs485)); + /* unset GPIOs */ +@@ -1451,9 +1451,9 @@ + unsigned long flags; + struct serial_rs485 aux; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + aux = port->rs485; +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + if (copy_to_user(rs485, &aux, sizeof(aux))) + return -EFAULT; +@@ -1481,7 +1481,7 @@ + uart_set_rs485_termination(port, &rs485); + uart_set_rs485_rx_during_tx(port, &rs485); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + ret = port->rs485_config(port, &tty->termios, &rs485); + if (!ret) { + port->rs485 = rs485; +@@ -1490,7 +1490,7 @@ + if (!(rs485.flags & SER_RS485_ENABLED)) + port->ops->set_mctrl(port, port->mctrl); + } +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + if (ret) { + /* restore old GPIO settings */ + gpiod_set_value_cansleep(port->rs485_term_gpio, +@@ -1515,9 +1515,9 @@ + if (!port->iso7816_config) + return -ENOTTY; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + aux = port->iso7816; +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + if (copy_to_user(iso7816, &aux, sizeof(aux))) + return -EFAULT; +@@ -1546,9 +1546,9 @@ + if (iso7816.reserved[i]) + return -EINVAL; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + ret = port->iso7816_config(port, &iso7816); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + if (ret) + return ret; + +@@ -1765,9 +1765,9 @@ + if (WARN(!uport, "detached port still initialized!\n")) + return; + +- spin_lock_irq(&uport->lock); ++ uart_port_lock_irq(uport); + uport->ops->stop_rx(uport); +- spin_unlock_irq(&uport->lock); ++ uart_port_unlock_irq(uport); + + uart_port_shutdown(port); + +@@ -1781,10 +1781,10 @@ + /* + * Free the transmit buffer. + */ +- spin_lock_irq(&uport->lock); ++ uart_port_lock_irq(uport); + buf = state->xmit.buf; + state->xmit.buf = NULL; +- spin_unlock_irq(&uport->lock); ++ uart_port_unlock_irq(uport); + + free_page((unsigned long)buf); + +@@ -1927,10 +1927,10 @@ + */ + if (WARN_ON(!uport)) + return true; +- spin_lock_irq(&uport->lock); ++ uart_port_lock_irq(uport); + uart_enable_ms(uport); + mctrl = uport->ops->get_mctrl(uport); +- spin_unlock_irq(&uport->lock); ++ uart_port_unlock_irq(uport); + uart_port_deref(uport); + + return mctrl & TIOCM_CAR; +@@ -2047,9 +2047,9 @@ + pm_state = state->pm_state; + if (pm_state != UART_PM_STATE_ON) + uart_change_pm(state, UART_PM_STATE_ON); +- spin_lock_irq(&uport->lock); ++ uart_port_lock_irq(uport); + status = uport->ops->get_mctrl(uport); +- spin_unlock_irq(&uport->lock); ++ uart_port_unlock_irq(uport); + if (pm_state != UART_PM_STATE_ON) + uart_change_pm(state, pm_state); + +@@ -2388,9 +2388,9 @@ + */ + if (!console_suspend_enabled && uart_console(uport)) { + if (uport->ops->start_rx) { +- spin_lock_irq(&uport->lock); ++ uart_port_lock_irq(uport); + uport->ops->stop_rx(uport); +- spin_unlock_irq(&uport->lock); ++ uart_port_unlock_irq(uport); + } + goto unlock; + } +@@ -2405,7 +2405,7 @@ + tty_port_set_suspended(port, true); + tty_port_set_initialized(port, false); + +- spin_lock_irq(&uport->lock); ++ uart_port_lock_irq(uport); + ops->stop_tx(uport); + if (!(uport->rs485.flags & SER_RS485_ENABLED)) + ops->set_mctrl(uport, 0); +@@ -2413,7 +2413,7 @@ + mctrl = uport->mctrl; + uport->mctrl = 0; + ops->stop_rx(uport); +- spin_unlock_irq(&uport->lock); ++ uart_port_unlock_irq(uport); + + /* + * Wait for the transmitter to empty. +@@ -2485,9 +2485,9 @@ + uart_change_pm(state, UART_PM_STATE_ON); + uport->ops->set_termios(uport, &termios, NULL); + if (!console_suspend_enabled && uport->ops->start_rx) { +- spin_lock_irq(&uport->lock); ++ uart_port_lock_irq(uport); + uport->ops->start_rx(uport); +- spin_unlock_irq(&uport->lock); ++ uart_port_unlock_irq(uport); + } + if (console_suspend_enabled) + console_start(uport->cons); +@@ -2498,10 +2498,10 @@ + int ret; + + uart_change_pm(state, UART_PM_STATE_ON); +- spin_lock_irq(&uport->lock); ++ uart_port_lock_irq(uport); + if (!(uport->rs485.flags & SER_RS485_ENABLED)) + ops->set_mctrl(uport, 0); +- spin_unlock_irq(&uport->lock); ++ uart_port_unlock_irq(uport); + if (console_suspend_enabled || !uart_console(uport)) { + /* Protected by port mutex for now */ + struct tty_struct *tty = port->tty; +@@ -2511,11 +2511,11 @@ + if (tty) + uart_change_line_settings(tty, state, NULL); + uart_rs485_config(uport); +- spin_lock_irq(&uport->lock); ++ uart_port_lock_irq(uport); + if (!(uport->rs485.flags & SER_RS485_ENABLED)) + ops->set_mctrl(uport, uport->mctrl); + ops->start_tx(uport); +- spin_unlock_irq(&uport->lock); ++ uart_port_unlock_irq(uport); + tty_port_set_initialized(port, true); + } else { + /* +@@ -2618,11 +2618,11 @@ + * keep the DTR setting that is set in uart_set_options() + * We probably don't need a spinlock around this, but + */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + port->mctrl &= TIOCM_DTR; + if (!(port->rs485.flags & SER_RS485_ENABLED)) + port->ops->set_mctrl(port, port->mctrl); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + uart_rs485_config(port); + +--- a/drivers/tty/serial/serial_port.c ++++ b/drivers/tty/serial/serial_port.c +@@ -35,10 +35,10 @@ + goto out; + + /* Flush any pending TX for the port */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + if (__serial_port_busy(port)) + port->ops->start_tx(port); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + out: + pm_runtime_mark_last_busy(dev); diff --git a/debian/patches-rt/0058-serial-mctrl_gpio-Use-port-lock-wrappers.patch b/debian/patches-rt/0058-serial-mctrl_gpio-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..46719cb07 --- /dev/null +++ b/debian/patches-rt/0058-serial-mctrl_gpio-Use-port-lock-wrappers.patch @@ -0,0 +1,58 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:15 +0206 +Subject: [PATCH 058/134] serial: mctrl_gpio: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-59-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/serial_mctrl_gpio.c | 4 ++-- + 1 file changed, 2 insertions(+), 2 deletions(-) + +--- a/drivers/tty/serial/serial_mctrl_gpio.c ++++ b/drivers/tty/serial/serial_mctrl_gpio.c +@@ -184,7 +184,7 @@ static irqreturn_t mctrl_gpio_irq_handle + + mctrl_gpio_get(gpios, &mctrl); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + mctrl_diff = mctrl ^ gpios->mctrl_prev; + gpios->mctrl_prev = mctrl; +@@ -205,7 +205,7 @@ static irqreturn_t mctrl_gpio_irq_handle + wake_up_interruptible(&port->state->port.delta_msr_wait); + } + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return IRQ_HANDLED; + } diff --git a/debian/patches-rt/0059-serial-txx9-Use-port-lock-wrappers.patch b/debian/patches-rt/0059-serial-txx9-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..bbe48684b --- /dev/null +++ b/debian/patches-rt/0059-serial-txx9-Use-port-lock-wrappers.patch @@ -0,0 +1,134 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:16 +0206 +Subject: [PATCH 059/134] serial: txx9: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-60-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/serial_txx9.c | 26 +++++++++++++------------- + 1 file changed, 13 insertions(+), 13 deletions(-) + +--- a/drivers/tty/serial/serial_txx9.c ++++ b/drivers/tty/serial/serial_txx9.c +@@ -335,13 +335,13 @@ static irqreturn_t serial_txx9_interrupt + unsigned int status; + + while (1) { +- spin_lock(&up->lock); ++ uart_port_lock(up); + status = sio_in(up, TXX9_SIDISR); + if (!(sio_in(up, TXX9_SIDICR) & TXX9_SIDICR_TIE)) + status &= ~TXX9_SIDISR_TDIS; + if (!(status & (TXX9_SIDISR_TDIS | TXX9_SIDISR_RDIS | + TXX9_SIDISR_TOUT))) { +- spin_unlock(&up->lock); ++ uart_port_unlock(up); + break; + } + +@@ -353,7 +353,7 @@ static irqreturn_t serial_txx9_interrupt + sio_mask(up, TXX9_SIDISR, + TXX9_SIDISR_TDIS | TXX9_SIDISR_RDIS | + TXX9_SIDISR_TOUT); +- spin_unlock(&up->lock); ++ uart_port_unlock(up); + + if (pass_counter++ > PASS_LIMIT) + break; +@@ -367,9 +367,9 @@ static unsigned int serial_txx9_tx_empty + unsigned long flags; + unsigned int ret; + +- spin_lock_irqsave(&up->lock, flags); ++ uart_port_lock_irqsave(up, &flags); + ret = (sio_in(up, TXX9_SICISR) & TXX9_SICISR_TXALS) ? TIOCSER_TEMT : 0; +- spin_unlock_irqrestore(&up->lock, flags); ++ uart_port_unlock_irqrestore(up, flags); + + return ret; + } +@@ -399,12 +399,12 @@ static void serial_txx9_break_ctl(struct + { + unsigned long flags; + +- spin_lock_irqsave(&up->lock, flags); ++ uart_port_lock_irqsave(up, &flags); + if (break_state == -1) + sio_set(up, TXX9_SIFLCR, TXX9_SIFLCR_TBRK); + else + sio_mask(up, TXX9_SIFLCR, TXX9_SIFLCR_TBRK); +- spin_unlock_irqrestore(&up->lock, flags); ++ uart_port_unlock_irqrestore(up, flags); + } + + #if defined(CONFIG_SERIAL_TXX9_CONSOLE) || defined(CONFIG_CONSOLE_POLL) +@@ -517,9 +517,9 @@ static int serial_txx9_startup(struct ua + /* + * Now, initialize the UART + */ +- spin_lock_irqsave(&up->lock, flags); ++ uart_port_lock_irqsave(up, &flags); + serial_txx9_set_mctrl(up, up->mctrl); +- spin_unlock_irqrestore(&up->lock, flags); ++ uart_port_unlock_irqrestore(up, flags); + + /* Enable RX/TX */ + sio_mask(up, TXX9_SIFLCR, TXX9_SIFLCR_RSDE | TXX9_SIFLCR_TSDE); +@@ -541,9 +541,9 @@ static void serial_txx9_shutdown(struct + */ + sio_out(up, TXX9_SIDICR, 0); /* disable all intrs */ + +- spin_lock_irqsave(&up->lock, flags); ++ uart_port_lock_irqsave(up, &flags); + serial_txx9_set_mctrl(up, up->mctrl); +- spin_unlock_irqrestore(&up->lock, flags); ++ uart_port_unlock_irqrestore(up, flags); + + /* + * Disable break condition +@@ -625,7 +625,7 @@ serial_txx9_set_termios(struct uart_port + * Ok, we're now changing the port state. Do it with + * interrupts disabled. + */ +- spin_lock_irqsave(&up->lock, flags); ++ uart_port_lock_irqsave(up, &flags); + + /* + * Update the per-port timeout. +@@ -676,7 +676,7 @@ serial_txx9_set_termios(struct uart_port + sio_out(up, TXX9_SIFCR, fcr); + + serial_txx9_set_mctrl(up, up->mctrl); +- spin_unlock_irqrestore(&up->lock, flags); ++ uart_port_unlock_irqrestore(up, flags); + } + + static void diff --git a/debian/patches-rt/0060-serial-sh-sci-Use-port-lock-wrappers.patch b/debian/patches-rt/0060-serial-sh-sci-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..6d039c665 --- /dev/null +++ b/debian/patches-rt/0060-serial-sh-sci-Use-port-lock-wrappers.patch @@ -0,0 +1,302 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:17 +0206 +Subject: [PATCH 060/134] serial: sh-sci: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-61-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/sh-sci.c | 68 ++++++++++++++++++++++---------------------- + 1 file changed, 34 insertions(+), 34 deletions(-) + +--- a/drivers/tty/serial/sh-sci.c ++++ b/drivers/tty/serial/sh-sci.c +@@ -1205,7 +1205,7 @@ static void sci_dma_tx_complete(void *ar + + dev_dbg(port->dev, "%s(%d)\n", __func__, port->line); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + uart_xmit_advance(port, s->tx_dma_len); + +@@ -1229,7 +1229,7 @@ static void sci_dma_tx_complete(void *ar + } + } + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /* Locking: called with port lock held */ +@@ -1320,7 +1320,7 @@ static void sci_dma_rx_complete(void *ar + dev_dbg(port->dev, "%s(%d) active cookie %d\n", __func__, port->line, + s->active_rx); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + active = sci_dma_rx_find_active(s); + if (active >= 0) +@@ -1347,20 +1347,20 @@ static void sci_dma_rx_complete(void *ar + + dma_async_issue_pending(chan); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + dev_dbg(port->dev, "%s: cookie %d #%d, new active cookie %d\n", + __func__, s->cookie_rx[active], active, s->active_rx); + return; + + fail: +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + dev_warn(port->dev, "Failed submitting Rx DMA descriptor\n"); + /* Switch to PIO */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + dmaengine_terminate_async(chan); + sci_dma_rx_chan_invalidate(s); + sci_dma_rx_reenable_irq(s); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void sci_dma_tx_release(struct sci_port *s) +@@ -1409,13 +1409,13 @@ static int sci_dma_rx_submit(struct sci_ + fail: + /* Switch to PIO */ + if (!port_lock_held) +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + if (i) + dmaengine_terminate_async(chan); + sci_dma_rx_chan_invalidate(s); + sci_start_rx(port); + if (!port_lock_held) +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + return -EAGAIN; + } + +@@ -1437,14 +1437,14 @@ static void sci_dma_tx_work_fn(struct wo + * transmit till the end, and then the rest. Take the port lock to get a + * consistent xmit buffer state. + */ +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + head = xmit->head; + tail = xmit->tail; + buf = s->tx_dma_addr + tail; + s->tx_dma_len = CIRC_CNT_TO_END(head, tail, UART_XMIT_SIZE); + if (!s->tx_dma_len) { + /* Transmit buffer has been flushed */ +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + return; + } + +@@ -1452,7 +1452,7 @@ static void sci_dma_tx_work_fn(struct wo + DMA_MEM_TO_DEV, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc) { +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + dev_warn(port->dev, "Failed preparing Tx DMA descriptor\n"); + goto switch_to_pio; + } +@@ -1464,12 +1464,12 @@ static void sci_dma_tx_work_fn(struct wo + desc->callback_param = s; + s->cookie_tx = dmaengine_submit(desc); + if (dma_submit_error(s->cookie_tx)) { +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + dev_warn(port->dev, "Failed submitting Tx DMA descriptor\n"); + goto switch_to_pio; + } + +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + dev_dbg(port->dev, "%s: %p: %d...%d, cookie %d\n", + __func__, xmit->buf, tail, head, s->cookie_tx); + +@@ -1477,10 +1477,10 @@ static void sci_dma_tx_work_fn(struct wo + return; + + switch_to_pio: +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + s->chan_tx = NULL; + sci_start_tx(port); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + return; + } + +@@ -1497,17 +1497,17 @@ static enum hrtimer_restart sci_dma_rx_t + + dev_dbg(port->dev, "DMA Rx timed out\n"); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + active = sci_dma_rx_find_active(s); + if (active < 0) { +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + return HRTIMER_NORESTART; + } + + status = dmaengine_tx_status(s->chan_rx, s->active_rx, &state); + if (status == DMA_COMPLETE) { +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + dev_dbg(port->dev, "Cookie %d #%d has already completed\n", + s->active_rx, active); + +@@ -1525,7 +1525,7 @@ static enum hrtimer_restart sci_dma_rx_t + */ + status = dmaengine_tx_status(s->chan_rx, s->active_rx, &state); + if (status == DMA_COMPLETE) { +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + dev_dbg(port->dev, "Transaction complete after DMA engine was stopped"); + return HRTIMER_NORESTART; + } +@@ -1546,7 +1546,7 @@ static enum hrtimer_restart sci_dma_rx_t + + sci_dma_rx_reenable_irq(s); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return HRTIMER_NORESTART; + } +@@ -1770,9 +1770,9 @@ static irqreturn_t sci_tx_interrupt(int + struct uart_port *port = ptr; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + sci_transmit_chars(port); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return IRQ_HANDLED; + } +@@ -1786,11 +1786,11 @@ static irqreturn_t sci_tx_end_interrupt( + if (port->type != PORT_SCI) + return sci_tx_interrupt(irq, ptr); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + ctrl = serial_port_in(port, SCSCR); + ctrl &= ~(SCSCR_TE | SCSCR_TEIE); + serial_port_out(port, SCSCR, ctrl); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return IRQ_HANDLED; + } +@@ -2187,7 +2187,7 @@ static void sci_break_ctl(struct uart_po + return; + } + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + scsptr = serial_port_in(port, SCSPTR); + scscr = serial_port_in(port, SCSCR); + +@@ -2201,7 +2201,7 @@ static void sci_break_ctl(struct uart_po + + serial_port_out(port, SCSPTR, scsptr); + serial_port_out(port, SCSCR, scscr); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int sci_startup(struct uart_port *port) +@@ -2233,7 +2233,7 @@ static void sci_shutdown(struct uart_por + s->autorts = false; + mctrl_gpio_disable_ms(to_sci_port(port)->gpios); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + sci_stop_rx(port); + sci_stop_tx(port); + /* +@@ -2243,7 +2243,7 @@ static void sci_shutdown(struct uart_por + scr = serial_port_in(port, SCSCR); + serial_port_out(port, SCSCR, scr & + (SCSCR_CKE1 | SCSCR_CKE0 | s->hscif_tot)); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + #ifdef CONFIG_SERIAL_SH_SCI_DMA + if (s->chan_rx_saved) { +@@ -2545,7 +2545,7 @@ static void sci_set_termios(struct uart_ + serial_port_out(port, SCCKS, sccks); + } + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + sci_reset(port); + +@@ -2667,7 +2667,7 @@ static void sci_set_termios(struct uart_ + if ((termios->c_cflag & CREAD) != 0) + sci_start_rx(port); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + sci_port_disable(s); + +@@ -3052,9 +3052,9 @@ static void serial_console_write(struct + if (port->sysrq) + locked = 0; + else if (oops_in_progress) +- locked = spin_trylock_irqsave(&port->lock, flags); ++ locked = uart_port_trylock_irqsave(port, &flags); + else +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* first save SCSCR then disable interrupts, keep clock source */ + ctrl = serial_port_in(port, SCSCR); +@@ -3074,7 +3074,7 @@ static void serial_console_write(struct + serial_port_out(port, SCSCR, ctrl); + + if (locked) +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int serial_console_setup(struct console *co, char *options) diff --git a/debian/patches-rt/0061-serial-sifive-Use-port-lock-wrappers.patch b/debian/patches-rt/0061-serial-sifive-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..a2babdbea --- /dev/null +++ b/debian/patches-rt/0061-serial-sifive-Use-port-lock-wrappers.patch @@ -0,0 +1,102 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:18 +0206 +Subject: [PATCH 061/134] serial: sifive: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-62-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/sifive.c | 16 ++++++++-------- + 1 file changed, 8 insertions(+), 8 deletions(-) + +--- a/drivers/tty/serial/sifive.c ++++ b/drivers/tty/serial/sifive.c +@@ -521,11 +521,11 @@ static irqreturn_t sifive_serial_irq(int + struct sifive_serial_port *ssp = dev_id; + u32 ip; + +- spin_lock(&ssp->port.lock); ++ uart_port_lock(&ssp->port); + + ip = __ssp_readl(ssp, SIFIVE_SERIAL_IP_OFFS); + if (!ip) { +- spin_unlock(&ssp->port.lock); ++ uart_port_unlock(&ssp->port); + return IRQ_NONE; + } + +@@ -534,7 +534,7 @@ static irqreturn_t sifive_serial_irq(int + if (ip & SIFIVE_SERIAL_IP_TXWM_MASK) + __ssp_transmit_chars(ssp); + +- spin_unlock(&ssp->port.lock); ++ uart_port_unlock(&ssp->port); + + return IRQ_HANDLED; + } +@@ -653,7 +653,7 @@ static void sifive_serial_set_termios(st + ssp->port.uartclk / 16); + __ssp_update_baud_rate(ssp, rate); + +- spin_lock_irqsave(&ssp->port.lock, flags); ++ uart_port_lock_irqsave(&ssp->port, &flags); + + /* Update the per-port timeout */ + uart_update_timeout(port, termios->c_cflag, rate); +@@ -670,7 +670,7 @@ static void sifive_serial_set_termios(st + if (v != old_v) + __ssp_writel(v, SIFIVE_SERIAL_RXCTRL_OFFS, ssp); + +- spin_unlock_irqrestore(&ssp->port.lock, flags); ++ uart_port_unlock_irqrestore(&ssp->port, flags); + } + + static void sifive_serial_release_port(struct uart_port *port) +@@ -795,9 +795,9 @@ static void sifive_serial_console_write( + if (ssp->port.sysrq) + locked = 0; + else if (oops_in_progress) +- locked = spin_trylock(&ssp->port.lock); ++ locked = uart_port_trylock(&ssp->port); + else +- spin_lock(&ssp->port.lock); ++ uart_port_lock(&ssp->port); + + ier = __ssp_readl(ssp, SIFIVE_SERIAL_IE_OFFS); + __ssp_writel(0, SIFIVE_SERIAL_IE_OFFS, ssp); +@@ -807,7 +807,7 @@ static void sifive_serial_console_write( + __ssp_writel(ier, SIFIVE_SERIAL_IE_OFFS, ssp); + + if (locked) +- spin_unlock(&ssp->port.lock); ++ uart_port_unlock(&ssp->port); + local_irq_restore(flags); + } + diff --git a/debian/patches-rt/0062-serial-sprd-Use-port-lock-wrappers.patch b/debian/patches-rt/0062-serial-sprd-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..5be78db09 --- /dev/null +++ b/debian/patches-rt/0062-serial-sprd-Use-port-lock-wrappers.patch @@ -0,0 +1,162 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:19 +0206 +Subject: [PATCH 062/134] serial: sprd: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-63-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/sprd_serial.c | 30 +++++++++++++++--------------- + 1 file changed, 15 insertions(+), 15 deletions(-) + +--- a/drivers/tty/serial/sprd_serial.c ++++ b/drivers/tty/serial/sprd_serial.c +@@ -247,7 +247,7 @@ static void sprd_complete_tx_dma(void *d + struct circ_buf *xmit = &port->state->xmit; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + dma_unmap_single(port->dev, sp->tx_dma.phys_addr, + sp->tx_dma.trans_len, DMA_TO_DEVICE); + +@@ -260,7 +260,7 @@ static void sprd_complete_tx_dma(void *d + sprd_tx_dma_config(port)) + sp->tx_dma.trans_len = 0; + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int sprd_uart_dma_submit(struct uart_port *port, +@@ -429,13 +429,13 @@ static void sprd_complete_rx_dma(void *d + enum dma_status status; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + status = dmaengine_tx_status(sp->rx_dma.chn, + sp->rx_dma.cookie, &state); + if (status != DMA_COMPLETE) { + sprd_stop_rx(port); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + return; + } + +@@ -449,7 +449,7 @@ static void sprd_complete_rx_dma(void *d + if (sprd_start_dma_rx(port)) + sprd_stop_rx(port); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int sprd_start_dma_rx(struct uart_port *port) +@@ -638,12 +638,12 @@ static irqreturn_t sprd_handle_irq(int i + struct uart_port *port = dev_id; + unsigned int ims; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + ims = serial_in(port, SPRD_IMSR); + + if (!ims) { +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + return IRQ_NONE; + } + +@@ -660,7 +660,7 @@ static irqreturn_t sprd_handle_irq(int i + if (ims & SPRD_IMSR_TX_FIFO_EMPTY) + sprd_tx(port); + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return IRQ_HANDLED; + } +@@ -727,13 +727,13 @@ static int sprd_startup(struct uart_port + serial_out(port, SPRD_CTL1, fc); + + /* enable interrupt */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + ien = serial_in(port, SPRD_IEN); + ien |= SPRD_IEN_BREAK_DETECT | SPRD_IEN_TIMEOUT; + if (!sp->rx_dma.enable) + ien |= SPRD_IEN_RX_FULL; + serial_out(port, SPRD_IEN, ien); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return 0; + } +@@ -793,7 +793,7 @@ static void sprd_set_termios(struct uart + lcr |= SPRD_LCR_EVEN_PAR; + } + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* update the per-port timeout */ + uart_update_timeout(port, termios->c_cflag, baud); +@@ -837,7 +837,7 @@ static void sprd_set_termios(struct uart + fc |= RX_TOUT_THLD_DEF | RX_HFC_THLD_DEF; + serial_out(port, SPRD_CTL1, fc); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + /* Don't rewrite B0 */ + if (tty_termios_baud_rate(termios)) +@@ -974,9 +974,9 @@ static void sprd_console_write(struct co + if (port->sysrq) + locked = 0; + else if (oops_in_progress) +- locked = spin_trylock_irqsave(&port->lock, flags); ++ locked = uart_port_trylock_irqsave(port, &flags); + else +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + uart_console_write(port, s, count, sprd_console_putchar); + +@@ -984,7 +984,7 @@ static void sprd_console_write(struct co + wait_for_xmitr(port); + + if (locked) +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int sprd_console_setup(struct console *co, char *options) diff --git a/debian/patches-rt/0063-serial-st-asc-Use-port-lock-wrappers.patch b/debian/patches-rt/0063-serial-st-asc-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..99f4358e6 --- /dev/null +++ b/debian/patches-rt/0063-serial-st-asc-Use-port-lock-wrappers.patch @@ -0,0 +1,110 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:20 +0206 +Subject: [PATCH 063/134] serial: st-asc: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-64-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/st-asc.c | 18 +++++++++--------- + 1 file changed, 9 insertions(+), 9 deletions(-) + +--- a/drivers/tty/serial/st-asc.c ++++ b/drivers/tty/serial/st-asc.c +@@ -319,7 +319,7 @@ static irqreturn_t asc_interrupt(int irq + struct uart_port *port = ptr; + u32 status; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + status = asc_in(port, ASC_STA); + +@@ -334,7 +334,7 @@ static irqreturn_t asc_interrupt(int irq + asc_transmit_chars(port); + } + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return IRQ_HANDLED; + } +@@ -452,10 +452,10 @@ static void asc_pm(struct uart_port *por + * we can come to turning it off. Note this is not called with + * the port spinlock held. + */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + ctl = asc_in(port, ASC_CTL) & ~ASC_CTL_RUN; + asc_out(port, ASC_CTL, ctl); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + clk_disable_unprepare(ascport->clk); + break; + } +@@ -480,7 +480,7 @@ static void asc_set_termios(struct uart_ + baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16); + cflag = termios->c_cflag; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* read control register */ + ctrl_val = asc_in(port, ASC_CTL); +@@ -594,7 +594,7 @@ static void asc_set_termios(struct uart_ + /* write final value and enable port */ + asc_out(port, ASC_CTL, (ctrl_val | ASC_CTL_RUN)); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *asc_type(struct uart_port *port) +@@ -849,9 +849,9 @@ static void asc_console_write(struct con + if (port->sysrq) + locked = 0; /* asc_interrupt has already claimed the lock */ + else if (oops_in_progress) +- locked = spin_trylock_irqsave(&port->lock, flags); ++ locked = uart_port_trylock_irqsave(port, &flags); + else +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* + * Disable interrupts so we don't get the IRQ line bouncing +@@ -869,7 +869,7 @@ static void asc_console_write(struct con + asc_out(port, ASC_INTEN, intenable); + + if (locked) +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int asc_console_setup(struct console *co, char *options) diff --git a/debian/patches-rt/0064-serial-stm32-Use-port-lock-wrappers.patch b/debian/patches-rt/0064-serial-stm32-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..cc261d43e --- /dev/null +++ b/debian/patches-rt/0064-serial-stm32-Use-port-lock-wrappers.patch @@ -0,0 +1,184 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:21 +0206 +Subject: [PATCH 064/134] serial: stm32: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-65-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/stm32-usart.c | 38 +++++++++++++++++++------------------- + 1 file changed, 19 insertions(+), 19 deletions(-) + +--- a/drivers/tty/serial/stm32-usart.c ++++ b/drivers/tty/serial/stm32-usart.c +@@ -537,7 +537,7 @@ static void stm32_usart_rx_dma_complete( + unsigned int size; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + size = stm32_usart_receive_chars(port, false); + uart_unlock_and_check_sysrq_irqrestore(port, flags); + if (size) +@@ -643,9 +643,9 @@ static void stm32_usart_tx_dma_complete( + stm32_usart_tx_dma_terminate(stm32port); + + /* Let's see if we have pending data to send */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + stm32_usart_transmit_chars(port); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void stm32_usart_tx_interrupt_enable(struct uart_port *port) +@@ -889,7 +889,7 @@ static irqreturn_t stm32_usart_interrupt + if (!stm32_port->throttled) { + if (((sr & USART_SR_RXNE) && !stm32_usart_rx_dma_started(stm32_port)) || + ((sr & USART_SR_ERR_MASK) && stm32_usart_rx_dma_started(stm32_port))) { +- spin_lock(&port->lock); ++ uart_port_lock(port); + size = stm32_usart_receive_chars(port, false); + uart_unlock_and_check_sysrq(port); + if (size) +@@ -898,14 +898,14 @@ static irqreturn_t stm32_usart_interrupt + } + + if ((sr & USART_SR_TXE) && !(stm32_port->tx_ch)) { +- spin_lock(&port->lock); ++ uart_port_lock(port); + stm32_usart_transmit_chars(port); +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + } + + /* Receiver timeout irq for DMA RX */ + if (stm32_usart_rx_dma_started(stm32_port) && !stm32_port->throttled) { +- spin_lock(&port->lock); ++ uart_port_lock(port); + size = stm32_usart_receive_chars(port, false); + uart_unlock_and_check_sysrq(port); + if (size) +@@ -993,7 +993,7 @@ static void stm32_usart_throttle(struct + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* + * Pause DMA transfer, so the RX data gets queued into the FIFO. +@@ -1006,7 +1006,7 @@ static void stm32_usart_throttle(struct + stm32_usart_clr_bits(port, ofs->cr3, stm32_port->cr3_irq); + + stm32_port->throttled = true; +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /* Unthrottle the remote, the input buffer can now accept data. */ +@@ -1016,7 +1016,7 @@ static void stm32_usart_unthrottle(struc + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + stm32_usart_set_bits(port, ofs->cr1, stm32_port->cr1_irq); + if (stm32_port->cr3_irq) + stm32_usart_set_bits(port, ofs->cr3, stm32_port->cr3_irq); +@@ -1030,7 +1030,7 @@ static void stm32_usart_unthrottle(struc + if (stm32_port->rx_ch) + stm32_usart_rx_dma_start_or_resume(port); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /* Receive stop */ +@@ -1158,7 +1158,7 @@ static void stm32_usart_set_termios(stru + + baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 8); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr, + isr, +@@ -1349,7 +1349,7 @@ static void stm32_usart_set_termios(stru + writel_relaxed(cr1, port->membase + ofs->cr1); + + stm32_usart_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit)); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + /* Handle modem control interrupts */ + if (UART_ENABLE_MS(port, termios->c_cflag)) +@@ -1399,9 +1399,9 @@ static void stm32_usart_pm(struct uart_p + pm_runtime_get_sync(port->dev); + break; + case UART_PM_STATE_OFF: +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + stm32_usart_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit)); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + pm_runtime_put_sync(port->dev); + break; + } +@@ -1884,9 +1884,9 @@ static void stm32_usart_console_write(st + int locked = 1; + + if (oops_in_progress) +- locked = spin_trylock_irqsave(&port->lock, flags); ++ locked = uart_port_trylock_irqsave(port, &flags); + else +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Save and disable interrupts, enable the transmitter */ + old_cr1 = readl_relaxed(port->membase + ofs->cr1); +@@ -1900,7 +1900,7 @@ static void stm32_usart_console_write(st + writel_relaxed(old_cr1, port->membase + ofs->cr1); + + if (locked) +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int stm32_usart_console_setup(struct console *co, char *options) +@@ -2035,7 +2035,7 @@ static int __maybe_unused stm32_usart_se + * low-power mode. + */ + if (stm32_port->rx_ch) { +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + /* Poll data from DMA RX buffer if any */ + if (!stm32_usart_rx_dma_pause(stm32_port)) + size += stm32_usart_receive_chars(port, true); diff --git a/debian/patches-rt/0065-serial-sunhv-Use-port-lock-wrappers.patch b/debian/patches-rt/0065-serial-sunhv-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..beacd2be7 --- /dev/null +++ b/debian/patches-rt/0065-serial-sunhv-Use-port-lock-wrappers.patch @@ -0,0 +1,149 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:22 +0206 +Subject: [PATCH 065/134] serial: sunhv: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-66-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/sunhv.c | 28 ++++++++++++++-------------- + 1 file changed, 14 insertions(+), 14 deletions(-) + +--- a/drivers/tty/serial/sunhv.c ++++ b/drivers/tty/serial/sunhv.c +@@ -217,10 +217,10 @@ static irqreturn_t sunhv_interrupt(int i + struct tty_port *tport; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + tport = receive_chars(port); + transmit_chars(port); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + if (tport) + tty_flip_buffer_push(tport); +@@ -271,7 +271,7 @@ static void sunhv_send_xchar(struct uart + if (ch == __DISABLED_CHAR) + return; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + while (limit-- > 0) { + long status = sun4v_con_putchar(ch); +@@ -280,7 +280,7 @@ static void sunhv_send_xchar(struct uart + udelay(1); + } + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /* port->lock held by caller. */ +@@ -295,7 +295,7 @@ static void sunhv_break_ctl(struct uart_ + unsigned long flags; + int limit = 10000; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + while (limit-- > 0) { + long status = sun4v_con_putchar(CON_BREAK); +@@ -304,7 +304,7 @@ static void sunhv_break_ctl(struct uart_ + udelay(1); + } + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + } + +@@ -328,7 +328,7 @@ static void sunhv_set_termios(struct uar + unsigned int iflag, cflag; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + iflag = termios->c_iflag; + cflag = termios->c_cflag; +@@ -343,7 +343,7 @@ static void sunhv_set_termios(struct uar + uart_update_timeout(port, cflag, + (port->uartclk / (16 * quot))); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *sunhv_type(struct uart_port *port) +@@ -437,9 +437,9 @@ static void sunhv_console_write_paged(st + int locked = 1; + + if (port->sysrq || oops_in_progress) +- locked = spin_trylock_irqsave(&port->lock, flags); ++ locked = uart_port_trylock_irqsave(port, &flags); + else +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + while (n > 0) { + unsigned long ra = __pa(con_write_page); +@@ -470,7 +470,7 @@ static void sunhv_console_write_paged(st + } + + if (locked) +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static inline void sunhv_console_putchar(struct uart_port *port, char c) +@@ -492,9 +492,9 @@ static void sunhv_console_write_bychar(s + int i, locked = 1; + + if (port->sysrq || oops_in_progress) +- locked = spin_trylock_irqsave(&port->lock, flags); ++ locked = uart_port_trylock_irqsave(port, &flags); + else +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + for (i = 0; i < n; i++) { + if (*s == '\n') +@@ -503,7 +503,7 @@ static void sunhv_console_write_bychar(s + } + + if (locked) +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static struct console sunhv_console = { diff --git a/debian/patches-rt/0066-serial-sunplus-uart-Use-port-lock-wrappers.patch b/debian/patches-rt/0066-serial-sunplus-uart-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..10ae6c477 --- /dev/null +++ b/debian/patches-rt/0066-serial-sunplus-uart-Use-port-lock-wrappers.patch @@ -0,0 +1,146 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:23 +0206 +Subject: [PATCH 066/134] serial: sunplus-uart: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-67-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/sunplus-uart.c | 26 +++++++++++++------------- + 1 file changed, 13 insertions(+), 13 deletions(-) + +--- a/drivers/tty/serial/sunplus-uart.c ++++ b/drivers/tty/serial/sunplus-uart.c +@@ -184,7 +184,7 @@ static void sunplus_break_ctl(struct uar + unsigned long flags; + unsigned int lcr; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + lcr = readl(port->membase + SUP_UART_LCR); + +@@ -195,7 +195,7 @@ static void sunplus_break_ctl(struct uar + + writel(lcr, port->membase + SUP_UART_LCR); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void transmit_chars(struct uart_port *port) +@@ -277,7 +277,7 @@ static irqreturn_t sunplus_uart_irq(int + struct uart_port *port = args; + unsigned int isc; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + isc = readl(port->membase + SUP_UART_ISC); + +@@ -287,7 +287,7 @@ static irqreturn_t sunplus_uart_irq(int + if (isc & SUP_UART_ISC_TX) + transmit_chars(port); + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return IRQ_HANDLED; + } +@@ -302,14 +302,14 @@ static int sunplus_startup(struct uart_p + if (ret) + return ret; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + /* isc define Bit[7:4] int setting, Bit[3:0] int status + * isc register will clean Bit[3:0] int status after read + * only do a write to Bit[7:4] int setting + */ + isc |= SUP_UART_ISC_RXM; + writel(isc, port->membase + SUP_UART_ISC); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return 0; + } +@@ -318,13 +318,13 @@ static void sunplus_shutdown(struct uart + { + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + /* isc define Bit[7:4] int setting, Bit[3:0] int status + * isc register will clean Bit[3:0] int status after read + * only do a write to Bit[7:4] int setting + */ + writel(0, port->membase + SUP_UART_ISC); /* disable all interrupt */ +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + free_irq(port->irq, port); + } +@@ -372,7 +372,7 @@ static void sunplus_set_termios(struct u + lcr |= UART_LCR_EPAR; + } + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + uart_update_timeout(port, termios->c_cflag, baud); + +@@ -407,7 +407,7 @@ static void sunplus_set_termios(struct u + writel(div_l, port->membase + SUP_UART_DIV_L); + writel(lcr, port->membase + SUP_UART_LCR); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void sunplus_set_ldisc(struct uart_port *port, struct ktermios *termios) +@@ -517,15 +517,15 @@ static void sunplus_console_write(struct + if (sunplus_console_ports[co->index]->port.sysrq) + locked = 0; + else if (oops_in_progress) +- locked = spin_trylock(&sunplus_console_ports[co->index]->port.lock); ++ locked = uart_port_trylock(&sunplus_console_ports[co->index]->port); + else +- spin_lock(&sunplus_console_ports[co->index]->port.lock); ++ uart_port_lock(&sunplus_console_ports[co->index]->port); + + uart_console_write(&sunplus_console_ports[co->index]->port, s, count, + sunplus_uart_console_putchar); + + if (locked) +- spin_unlock(&sunplus_console_ports[co->index]->port.lock); ++ uart_port_unlock(&sunplus_console_ports[co->index]->port); + + local_irq_restore(flags); + } diff --git a/debian/patches-rt/0067-serial-sunsab-Use-port-lock-wrappers.patch b/debian/patches-rt/0067-serial-sunsab-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..b96d5080c --- /dev/null +++ b/debian/patches-rt/0067-serial-sunsab-Use-port-lock-wrappers.patch @@ -0,0 +1,176 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:24 +0206 +Subject: [PATCH 067/134] serial: sunsab: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-68-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/sunsab.c | 34 +++++++++++++++++----------------- + 1 file changed, 17 insertions(+), 17 deletions(-) + +--- a/drivers/tty/serial/sunsab.c ++++ b/drivers/tty/serial/sunsab.c +@@ -310,7 +310,7 @@ static irqreturn_t sunsab_interrupt(int + unsigned long flags; + unsigned char gis; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + status.stat = 0; + gis = readb(&up->regs->r.gis) >> up->gis_shift; +@@ -331,7 +331,7 @@ static irqreturn_t sunsab_interrupt(int + transmit_chars(up, &status); + } + +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + if (port) + tty_flip_buffer_push(port); +@@ -473,12 +473,12 @@ static void sunsab_send_xchar(struct uar + if (ch == __DISABLED_CHAR) + return; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + sunsab_tec_wait(up); + writeb(ch, &up->regs->w.tic); + +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + /* port->lock held by caller. */ +@@ -499,7 +499,7 @@ static void sunsab_break_ctl(struct uart + unsigned long flags; + unsigned char val; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + val = up->cached_dafo; + if (break_state) +@@ -512,7 +512,7 @@ static void sunsab_break_ctl(struct uart + if (test_bit(SAB82532_XPR, &up->irqflags)) + sunsab_tx_idle(up); + +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + /* port->lock is not held. */ +@@ -527,7 +527,7 @@ static int sunsab_startup(struct uart_po + if (err) + return err; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + /* + * Wait for any commands or immediate characters +@@ -582,7 +582,7 @@ static int sunsab_startup(struct uart_po + set_bit(SAB82532_ALLS, &up->irqflags); + set_bit(SAB82532_XPR, &up->irqflags); + +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + return 0; + } +@@ -594,7 +594,7 @@ static void sunsab_shutdown(struct uart_ + container_of(port, struct uart_sunsab_port, port); + unsigned long flags; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + /* Disable Interrupts */ + up->interrupt_mask0 = 0xff; +@@ -628,7 +628,7 @@ static void sunsab_shutdown(struct uart_ + writeb(tmp, &up->regs->rw.ccr0); + #endif + +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + free_irq(up->port.irq, up); + } + +@@ -779,9 +779,9 @@ static void sunsab_set_termios(struct ua + unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000); + unsigned int quot = uart_get_divisor(port, baud); + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + sunsab_convert_to_sab(up, termios->c_cflag, termios->c_iflag, baud, quot); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static const char *sunsab_type(struct uart_port *port) +@@ -857,15 +857,15 @@ static void sunsab_console_write(struct + int locked = 1; + + if (up->port.sysrq || oops_in_progress) +- locked = spin_trylock_irqsave(&up->port.lock, flags); ++ locked = uart_port_trylock_irqsave(&up->port, &flags); + else +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + uart_console_write(&up->port, s, n, sunsab_console_putchar); + sunsab_tec_wait(up); + + if (locked) +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static int sunsab_console_setup(struct console *con, char *options) +@@ -914,7 +914,7 @@ static int sunsab_console_setup(struct c + */ + sunsab_startup(&up->port); + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + /* + * Finally, enable interrupts +@@ -932,7 +932,7 @@ static int sunsab_console_setup(struct c + sunsab_convert_to_sab(up, con->cflag, 0, baud, quot); + sunsab_set_mctrl(&up->port, TIOCM_DTR | TIOCM_RTS); + +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + return 0; + } diff --git a/debian/patches-rt/0068-serial-sunsu-Use-port-lock-wrappers.patch b/debian/patches-rt/0068-serial-sunsu-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..77945a1ed --- /dev/null +++ b/debian/patches-rt/0068-serial-sunsu-Use-port-lock-wrappers.patch @@ -0,0 +1,219 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:25 +0206 +Subject: [PATCH 068/134] serial: sunsu: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-69-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/sunsu.c | 46 ++++++++++++++++++++++----------------------- + 1 file changed, 23 insertions(+), 23 deletions(-) + +--- a/drivers/tty/serial/sunsu.c ++++ b/drivers/tty/serial/sunsu.c +@@ -212,9 +212,9 @@ static void enable_rsa(struct uart_sunsu + { + if (up->port.type == PORT_RSA) { + if (up->port.uartclk != SERIAL_RSA_BAUD_BASE * 16) { +- spin_lock_irq(&up->port.lock); ++ uart_port_lock_irq(&up->port); + __enable_rsa(up); +- spin_unlock_irq(&up->port.lock); ++ uart_port_unlock_irq(&up->port); + } + if (up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16) + serial_outp(up, UART_RSA_FRR, 0); +@@ -234,7 +234,7 @@ static void disable_rsa(struct uart_suns + + if (up->port.type == PORT_RSA && + up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16) { +- spin_lock_irq(&up->port.lock); ++ uart_port_lock_irq(&up->port); + + mode = serial_inp(up, UART_RSA_MSR); + result = !(mode & UART_RSA_MSR_FIFO); +@@ -247,7 +247,7 @@ static void disable_rsa(struct uart_suns + + if (result) + up->port.uartclk = SERIAL_RSA_BAUD_BASE_LO * 16; +- spin_unlock_irq(&up->port.lock); ++ uart_port_unlock_irq(&up->port); + } + } + #endif /* CONFIG_SERIAL_8250_RSA */ +@@ -311,10 +311,10 @@ static void sunsu_enable_ms(struct uart_ + container_of(port, struct uart_sunsu_port, port); + unsigned long flags; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + up->ier |= UART_IER_MSI; + serial_out(up, UART_IER, up->ier); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static void +@@ -456,7 +456,7 @@ static irqreturn_t sunsu_serial_interrup + unsigned long flags; + unsigned char status; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + do { + status = serial_inp(up, UART_LSR); +@@ -470,7 +470,7 @@ static irqreturn_t sunsu_serial_interrup + + } while (!(serial_in(up, UART_IIR) & UART_IIR_NO_INT)); + +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + return IRQ_HANDLED; + } +@@ -545,9 +545,9 @@ static unsigned int sunsu_tx_empty(struc + unsigned long flags; + unsigned int ret; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0; +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + return ret; + } +@@ -599,13 +599,13 @@ static void sunsu_break_ctl(struct uart_ + container_of(port, struct uart_sunsu_port, port); + unsigned long flags; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + if (break_state == -1) + up->lcr |= UART_LCR_SBC; + else + up->lcr &= ~UART_LCR_SBC; + serial_out(up, UART_LCR, up->lcr); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static int sunsu_startup(struct uart_port *port) +@@ -683,12 +683,12 @@ static int sunsu_startup(struct uart_por + */ + serial_outp(up, UART_LCR, UART_LCR_WLEN8); + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + up->port.mctrl |= TIOCM_OUT2; + + sunsu_set_mctrl(&up->port, up->port.mctrl); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + /* + * Finally, enable interrupts. Note: Modem status interrupts +@@ -731,7 +731,7 @@ static void sunsu_shutdown(struct uart_p + up->ier = 0; + serial_outp(up, UART_IER, 0); + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + if (up->port.flags & UPF_FOURPORT) { + /* reset interrupts on the AST Fourport board */ + inb((up->port.iobase & 0xfe0) | 0x1f); +@@ -740,7 +740,7 @@ static void sunsu_shutdown(struct uart_p + up->port.mctrl &= ~TIOCM_OUT2; + + sunsu_set_mctrl(&up->port, up->port.mctrl); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + /* + * Disable break condition and FIFOs +@@ -826,7 +826,7 @@ sunsu_change_speed(struct uart_port *por + * Ok, we're now changing the port state. Do it with + * interrupts disabled. + */ +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + /* + * Update the per-port timeout. +@@ -891,7 +891,7 @@ sunsu_change_speed(struct uart_port *por + + up->cflag = cflag; + +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static void +@@ -1038,7 +1038,7 @@ static void sunsu_autoconfig(struct uart + up->type_probed = PORT_UNKNOWN; + up->port.iotype = UPIO_MEM; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + if (!(up->port.flags & UPF_BUGGY_UART)) { + /* +@@ -1173,7 +1173,7 @@ static void sunsu_autoconfig(struct uart + serial_outp(up, UART_IER, 0); + + out: +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static struct uart_driver sunsu_reg = { +@@ -1298,9 +1298,9 @@ static void sunsu_console_write(struct c + int locked = 1; + + if (up->port.sysrq || oops_in_progress) +- locked = spin_trylock_irqsave(&up->port.lock, flags); ++ locked = uart_port_trylock_irqsave(&up->port, &flags); + else +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + /* + * First save the UER then disable the interrupts +@@ -1318,7 +1318,7 @@ static void sunsu_console_write(struct c + serial_out(up, UART_IER, ier); + + if (locked) +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + /* diff --git a/debian/patches-rt/0069-serial-sunzilog-Use-port-lock-wrappers.patch b/debian/patches-rt/0069-serial-sunzilog-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..dca4327a4 --- /dev/null +++ b/debian/patches-rt/0069-serial-sunzilog-Use-port-lock-wrappers.patch @@ -0,0 +1,211 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:26 +0206 +Subject: [PATCH 069/134] serial: sunzilog: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-70-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/sunzilog.c | 42 +++++++++++++++++++++--------------------- + 1 file changed, 21 insertions(+), 21 deletions(-) + +--- a/drivers/tty/serial/sunzilog.c ++++ b/drivers/tty/serial/sunzilog.c +@@ -531,7 +531,7 @@ static irqreturn_t sunzilog_interrupt(in + struct tty_port *port; + unsigned char r3; + +- spin_lock(&up->port.lock); ++ uart_port_lock(&up->port); + r3 = read_zsreg(channel, R3); + + /* Channel A */ +@@ -548,7 +548,7 @@ static irqreturn_t sunzilog_interrupt(in + if (r3 & CHATxIP) + sunzilog_transmit_chars(up, channel); + } +- spin_unlock(&up->port.lock); ++ uart_port_unlock(&up->port); + + if (port) + tty_flip_buffer_push(port); +@@ -557,7 +557,7 @@ static irqreturn_t sunzilog_interrupt(in + up = up->next; + channel = ZILOG_CHANNEL_FROM_PORT(&up->port); + +- spin_lock(&up->port.lock); ++ uart_port_lock(&up->port); + port = NULL; + if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) { + writeb(RES_H_IUS, &channel->control); +@@ -571,7 +571,7 @@ static irqreturn_t sunzilog_interrupt(in + if (r3 & CHBTxIP) + sunzilog_transmit_chars(up, channel); + } +- spin_unlock(&up->port.lock); ++ uart_port_unlock(&up->port); + + if (port) + tty_flip_buffer_push(port); +@@ -604,11 +604,11 @@ static unsigned int sunzilog_tx_empty(st + unsigned char status; + unsigned int ret; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + status = sunzilog_read_channel_status(port); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + if (status & Tx_BUF_EMP) + ret = TIOCSER_TEMT; +@@ -764,7 +764,7 @@ static void sunzilog_break_ctl(struct ua + else + clear_bits |= SND_BRK; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + new_reg = (up->curregs[R5] | set_bits) & ~clear_bits; + if (new_reg != up->curregs[R5]) { +@@ -774,7 +774,7 @@ static void sunzilog_break_ctl(struct ua + write_zsreg(channel, R5, up->curregs[R5]); + } + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void __sunzilog_startup(struct uart_sunzilog_port *up) +@@ -800,9 +800,9 @@ static int sunzilog_startup(struct uart_ + if (ZS_IS_CONS(up)) + return 0; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + __sunzilog_startup(up); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + return 0; + } + +@@ -840,7 +840,7 @@ static void sunzilog_shutdown(struct uar + if (ZS_IS_CONS(up)) + return; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + channel = ZILOG_CHANNEL_FROM_PORT(port); + +@@ -853,7 +853,7 @@ static void sunzilog_shutdown(struct uar + up->curregs[R5] &= ~SND_BRK; + sunzilog_maybe_update_regs(up, channel); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /* Shared by TTY driver and serial console setup. The port lock is held +@@ -945,7 +945,7 @@ sunzilog_set_termios(struct uart_port *p + + baud = uart_get_baud_rate(port, termios, old, 1200, 76800); + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR); + +@@ -962,7 +962,7 @@ sunzilog_set_termios(struct uart_port *p + + uart_update_timeout(port, termios->c_cflag, baud); + +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static const char *sunzilog_type(struct uart_port *port) +@@ -1201,15 +1201,15 @@ sunzilog_console_write(struct console *c + int locked = 1; + + if (up->port.sysrq || oops_in_progress) +- locked = spin_trylock_irqsave(&up->port.lock, flags); ++ locked = uart_port_trylock_irqsave(&up->port, &flags); + else +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + uart_console_write(&up->port, s, count, sunzilog_putchar); + udelay(2); + + if (locked) +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static int __init sunzilog_console_setup(struct console *con, char *options) +@@ -1244,7 +1244,7 @@ static int __init sunzilog_console_setup + + brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR); + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + up->curregs[R15] |= BRKIE; + sunzilog_convert_to_zs(up, con->cflag, 0, brg); +@@ -1252,7 +1252,7 @@ static int __init sunzilog_console_setup + sunzilog_set_mctrl(&up->port, TIOCM_DTR | TIOCM_RTS); + __sunzilog_startup(up); + +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + return 0; + } +@@ -1333,7 +1333,7 @@ static void sunzilog_init_hw(struct uart + + channel = ZILOG_CHANNEL_FROM_PORT(&up->port); + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + if (ZS_IS_CHANNEL_A(up)) { + write_zsreg(channel, R9, FHWRES); + ZSDELAY_LONG(); +@@ -1383,7 +1383,7 @@ static void sunzilog_init_hw(struct uart + write_zsreg(channel, R9, up->curregs[R9]); + } + +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + #ifdef CONFIG_SERIO + if (up->flags & (SUNZILOG_FLAG_CONS_KEYB | diff --git a/debian/patches-rt/0070-serial-timbuart-Use-port-lock-wrappers.patch b/debian/patches-rt/0070-serial-timbuart-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..2d5a3d95e --- /dev/null +++ b/debian/patches-rt/0070-serial-timbuart-Use-port-lock-wrappers.patch @@ -0,0 +1,71 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:27 +0206 +Subject: [PATCH 070/134] serial: timbuart: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-71-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/timbuart.c | 8 ++++---- + 1 file changed, 4 insertions(+), 4 deletions(-) + +--- a/drivers/tty/serial/timbuart.c ++++ b/drivers/tty/serial/timbuart.c +@@ -174,7 +174,7 @@ static void timbuart_tasklet(struct task + struct timbuart_port *uart = from_tasklet(uart, t, tasklet); + u32 isr, ier = 0; + +- spin_lock(&uart->port.lock); ++ uart_port_lock(&uart->port); + + isr = ioread32(uart->port.membase + TIMBUART_ISR); + dev_dbg(uart->port.dev, "%s ISR: %x\n", __func__, isr); +@@ -189,7 +189,7 @@ static void timbuart_tasklet(struct task + + iowrite32(ier, uart->port.membase + TIMBUART_IER); + +- spin_unlock(&uart->port.lock); ++ uart_port_unlock(&uart->port); + dev_dbg(uart->port.dev, "%s leaving\n", __func__); + } + +@@ -295,10 +295,10 @@ static void timbuart_set_termios(struct + tty_termios_copy_hw(termios, old); + tty_termios_encode_baud_rate(termios, baud, baud); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + iowrite8((u8)bindex, port->membase + TIMBUART_BAUDRATE); + uart_update_timeout(port, termios->c_cflag, baud); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *timbuart_type(struct uart_port *port) diff --git a/debian/patches-rt/0071-serial-uartlite-Use-port-lock-wrappers.patch b/debian/patches-rt/0071-serial-uartlite-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..13c64d7ee --- /dev/null +++ b/debian/patches-rt/0071-serial-uartlite-Use-port-lock-wrappers.patch @@ -0,0 +1,105 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:28 +0206 +Subject: [PATCH 071/134] serial: uartlite: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-72-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/uartlite.c | 18 +++++++++--------- + 1 file changed, 9 insertions(+), 9 deletions(-) + +--- a/drivers/tty/serial/uartlite.c ++++ b/drivers/tty/serial/uartlite.c +@@ -216,11 +216,11 @@ static irqreturn_t ulite_isr(int irq, vo + unsigned long flags; + + do { +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + stat = uart_in32(ULITE_STATUS, port); + busy = ulite_receive(port, stat); + busy |= ulite_transmit(port, stat); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + n++; + } while (busy); + +@@ -238,9 +238,9 @@ static unsigned int ulite_tx_empty(struc + unsigned long flags; + unsigned int ret; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + ret = uart_in32(ULITE_STATUS, port); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return ret & ULITE_STATUS_TXEMPTY ? TIOCSER_TEMT : 0; + } +@@ -323,7 +323,7 @@ static void ulite_set_termios(struct uar + termios->c_cflag |= pdata->cflags & (PARENB | PARODD | CSIZE); + tty_termios_encode_baud_rate(termios, pdata->baud, pdata->baud); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + port->read_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN + | ULITE_STATUS_TXFULL; +@@ -346,7 +346,7 @@ static void ulite_set_termios(struct uar + /* update timeout */ + uart_update_timeout(port, termios->c_cflag, pdata->baud); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *ulite_type(struct uart_port *port) +@@ -495,9 +495,9 @@ static void ulite_console_write(struct c + int locked = 1; + + if (oops_in_progress) { +- locked = spin_trylock_irqsave(&port->lock, flags); ++ locked = uart_port_trylock_irqsave(port, &flags); + } else +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* save and disable interrupt */ + ier = uart_in32(ULITE_STATUS, port) & ULITE_STATUS_IE; +@@ -512,7 +512,7 @@ static void ulite_console_write(struct c + uart_out32(ULITE_CONTROL_IE, ULITE_CONTROL, port); + + if (locked) +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int ulite_console_setup(struct console *co, char *options) diff --git a/debian/patches-rt/0072-serial-ucc_uart-Use-port-lock-wrappers.patch b/debian/patches-rt/0072-serial-ucc_uart-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..30681434a --- /dev/null +++ b/debian/patches-rt/0072-serial-ucc_uart-Use-port-lock-wrappers.patch @@ -0,0 +1,59 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:29 +0206 +Subject: [PATCH 072/134] serial: ucc_uart: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Acked-by: Timur Tabi +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-73-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/ucc_uart.c | 4 ++-- + 1 file changed, 2 insertions(+), 2 deletions(-) + +--- a/drivers/tty/serial/ucc_uart.c ++++ b/drivers/tty/serial/ucc_uart.c +@@ -931,7 +931,7 @@ static void qe_uart_set_termios(struct u + baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16); + + /* Do we really need a spinlock here? */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Update the per-port timeout. */ + uart_update_timeout(port, termios->c_cflag, baud); +@@ -949,7 +949,7 @@ static void qe_uart_set_termios(struct u + qe_setbrg(qe_port->us_info.tx_clock, baud, 16); + } + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /* diff --git a/debian/patches-rt/0073-serial-vt8500-Use-port-lock-wrappers.patch b/debian/patches-rt/0073-serial-vt8500-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..7209ed066 --- /dev/null +++ b/debian/patches-rt/0073-serial-vt8500-Use-port-lock-wrappers.patch @@ -0,0 +1,76 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:30 +0206 +Subject: [PATCH 073/134] serial: vt8500: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-74-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/vt8500_serial.c | 8 ++++---- + 1 file changed, 4 insertions(+), 4 deletions(-) + +--- a/drivers/tty/serial/vt8500_serial.c ++++ b/drivers/tty/serial/vt8500_serial.c +@@ -227,7 +227,7 @@ static irqreturn_t vt8500_irq(int irq, v + struct uart_port *port = dev_id; + unsigned long isr; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + isr = vt8500_read(port, VT8500_URISR); + + /* Acknowledge active status bits */ +@@ -240,7 +240,7 @@ static irqreturn_t vt8500_irq(int irq, v + if (isr & TCTS) + handle_delta_cts(port); + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return IRQ_HANDLED; + } +@@ -342,7 +342,7 @@ static void vt8500_set_termios(struct ua + unsigned int baud, lcr; + unsigned int loops = 1000; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* calculate and set baud rate */ + baud = uart_get_baud_rate(port, termios, old, 900, 921600); +@@ -410,7 +410,7 @@ static void vt8500_set_termios(struct ua + vt8500_write(&vt8500_port->uart, 0x881, VT8500_URFCR); + vt8500_write(&vt8500_port->uart, vt8500_port->ier, VT8500_URIER); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *vt8500_type(struct uart_port *port) diff --git a/debian/patches-rt/0074-serial-xilinx_uartps-Use-port-lock-wrappers.patch b/debian/patches-rt/0074-serial-xilinx_uartps-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..307ee6df7 --- /dev/null +++ b/debian/patches-rt/0074-serial-xilinx_uartps-Use-port-lock-wrappers.patch @@ -0,0 +1,276 @@ +From: Thomas Gleixner +Date: Thu, 14 Sep 2023 20:44:31 +0206 +Subject: [PATCH 074/134] serial: xilinx_uartps: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner +Signed-off-by: John Ogness +Link: https://lore.kernel.org/r/20230914183831.587273-75-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/xilinx_uartps.c | 56 ++++++++++++++++++------------------- + 1 file changed, 28 insertions(+), 28 deletions(-) + +--- a/drivers/tty/serial/xilinx_uartps.c ++++ b/drivers/tty/serial/xilinx_uartps.c +@@ -346,7 +346,7 @@ static irqreturn_t cdns_uart_isr(int irq + struct uart_port *port = (struct uart_port *)dev_id; + unsigned int isrstatus; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + /* Read the interrupt status register to determine which + * interrupt(s) is/are active and clear them. +@@ -369,7 +369,7 @@ static irqreturn_t cdns_uart_isr(int irq + !(readl(port->membase + CDNS_UART_CR) & CDNS_UART_CR_RX_DIS)) + cdns_uart_handle_rx(dev_id, isrstatus); + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + return IRQ_HANDLED; + } + +@@ -506,14 +506,14 @@ static int cdns_uart_clk_notifier_cb(str + return NOTIFY_BAD; + } + +- spin_lock_irqsave(&cdns_uart->port->lock, flags); ++ uart_port_lock_irqsave(cdns_uart->port, &flags); + + /* Disable the TX and RX to set baud rate */ + ctrl_reg = readl(port->membase + CDNS_UART_CR); + ctrl_reg |= CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS; + writel(ctrl_reg, port->membase + CDNS_UART_CR); + +- spin_unlock_irqrestore(&cdns_uart->port->lock, flags); ++ uart_port_unlock_irqrestore(cdns_uart->port, flags); + + return NOTIFY_OK; + } +@@ -523,7 +523,7 @@ static int cdns_uart_clk_notifier_cb(str + * frequency. + */ + +- spin_lock_irqsave(&cdns_uart->port->lock, flags); ++ uart_port_lock_irqsave(cdns_uart->port, &flags); + + locked = 1; + port->uartclk = ndata->new_rate; +@@ -533,7 +533,7 @@ static int cdns_uart_clk_notifier_cb(str + fallthrough; + case ABORT_RATE_CHANGE: + if (!locked) +- spin_lock_irqsave(&cdns_uart->port->lock, flags); ++ uart_port_lock_irqsave(cdns_uart->port, &flags); + + /* Set TX/RX Reset */ + ctrl_reg = readl(port->membase + CDNS_UART_CR); +@@ -555,7 +555,7 @@ static int cdns_uart_clk_notifier_cb(str + ctrl_reg |= CDNS_UART_CR_TX_EN | CDNS_UART_CR_RX_EN; + writel(ctrl_reg, port->membase + CDNS_UART_CR); + +- spin_unlock_irqrestore(&cdns_uart->port->lock, flags); ++ uart_port_unlock_irqrestore(cdns_uart->port, flags); + + return NOTIFY_OK; + default: +@@ -652,7 +652,7 @@ static void cdns_uart_break_ctl(struct u + unsigned int status; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + status = readl(port->membase + CDNS_UART_CR); + +@@ -664,7 +664,7 @@ static void cdns_uart_break_ctl(struct u + writel(CDNS_UART_CR_STOPBRK | status, + port->membase + CDNS_UART_CR); + } +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /** +@@ -683,7 +683,7 @@ static void cdns_uart_set_termios(struct + unsigned long flags; + unsigned int ctrl_reg, mode_reg; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Disable the TX and RX to set baud rate */ + ctrl_reg = readl(port->membase + CDNS_UART_CR); +@@ -794,7 +794,7 @@ static void cdns_uart_set_termios(struct + cval &= ~CDNS_UART_MODEMCR_FCM; + writel(cval, port->membase + CDNS_UART_MODEMCR); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /** +@@ -813,7 +813,7 @@ static int cdns_uart_startup(struct uart + + is_brk_support = cdns_uart->quirks & CDNS_UART_RXBS_SUPPORT; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Disable the TX and RX */ + writel(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS, +@@ -861,7 +861,7 @@ static int cdns_uart_startup(struct uart + writel(readl(port->membase + CDNS_UART_ISR), + port->membase + CDNS_UART_ISR); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + ret = request_irq(port->irq, cdns_uart_isr, 0, CDNS_UART_NAME, port); + if (ret) { +@@ -889,7 +889,7 @@ static void cdns_uart_shutdown(struct ua + int status; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Disable interrupts */ + status = readl(port->membase + CDNS_UART_IMR); +@@ -900,7 +900,7 @@ static void cdns_uart_shutdown(struct ua + writel(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS, + port->membase + CDNS_UART_CR); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + free_irq(port->irq, port); + } +@@ -1050,7 +1050,7 @@ static int cdns_uart_poll_get_char(struc + int c; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Check if FIFO is empty */ + if (readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_RXEMPTY) +@@ -1058,7 +1058,7 @@ static int cdns_uart_poll_get_char(struc + else /* Read a character */ + c = (unsigned char) readl(port->membase + CDNS_UART_FIFO); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return c; + } +@@ -1067,7 +1067,7 @@ static void cdns_uart_poll_put_char(stru + { + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Wait until FIFO is empty */ + while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXEMPTY)) +@@ -1080,7 +1080,7 @@ static void cdns_uart_poll_put_char(stru + while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXEMPTY)) + cpu_relax(); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + #endif + +@@ -1232,9 +1232,9 @@ static void cdns_uart_console_write(stru + if (port->sysrq) + locked = 0; + else if (oops_in_progress) +- locked = spin_trylock_irqsave(&port->lock, flags); ++ locked = uart_port_trylock_irqsave(port, &flags); + else +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* save and disable interrupt */ + imr = readl(port->membase + CDNS_UART_IMR); +@@ -1257,7 +1257,7 @@ static void cdns_uart_console_write(stru + writel(imr, port->membase + CDNS_UART_IER); + + if (locked) +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /** +@@ -1325,7 +1325,7 @@ static int cdns_uart_suspend(struct devi + if (console_suspend_enabled && uart_console(port) && may_wake) { + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + /* Empty the receive FIFO 1st before making changes */ + while (!(readl(port->membase + CDNS_UART_SR) & + CDNS_UART_SR_RXEMPTY)) +@@ -1334,7 +1334,7 @@ static int cdns_uart_suspend(struct devi + writel(1, port->membase + CDNS_UART_RXWM); + /* disable RX timeout interrups */ + writel(CDNS_UART_IXR_TOUT, port->membase + CDNS_UART_IDR); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /* +@@ -1372,7 +1372,7 @@ static int cdns_uart_resume(struct devic + return ret; + } + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Set TX/RX Reset */ + ctrl_reg = readl(port->membase + CDNS_UART_CR); +@@ -1392,14 +1392,14 @@ static int cdns_uart_resume(struct devic + + clk_disable(cdns_uart->uartclk); + clk_disable(cdns_uart->pclk); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } else { +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + /* restore original rx trigger level */ + writel(rx_trigger_level, port->membase + CDNS_UART_RXWM); + /* enable RX timeout interrupt */ + writel(CDNS_UART_IXR_TOUT, port->membase + CDNS_UART_IER); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + return uart_resume_port(cdns_uart->cdns_uart_driver, port); diff --git a/debian/patches-rt/0075-printk-Add-non-BKL-nbcon-console-basic-infrastructur.patch b/debian/patches-rt/0075-printk-Add-non-BKL-nbcon-console-basic-infrastructur.patch new file mode 100644 index 000000000..00f7850c3 --- /dev/null +++ b/debian/patches-rt/0075-printk-Add-non-BKL-nbcon-console-basic-infrastructur.patch @@ -0,0 +1,261 @@ +From: Thomas Gleixner +Date: Sat, 16 Sep 2023 21:26:00 +0206 +Subject: [PATCH 075/134] printk: Add non-BKL (nbcon) console basic + infrastructure +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +The current console/printk subsystem is protected by a Big Kernel Lock, +(aka console_lock) which has ill defined semantics and is more or less +stateless. This puts severe limitations on the console subsystem and +makes forced takeover and output in emergency and panic situations a +fragile endeavour that is based on try and pray. + +The goal of non-BKL (nbcon) consoles is to break out of the console lock +jail and to provide a new infrastructure that avoids the pitfalls and +also allows console drivers to be gradually converted over. + +The proposed infrastructure aims for the following properties: + + - Per console locking instead of global locking + - Per console state that allows to make informed decisions + - Stateful handover and takeover + +As a first step, state is added to struct console. The per console state +is an atomic_t using a 32bit bit field. + +Reserve state bits, which will be populated later in the series. Wire +it up into the console register/unregister functionality. + +It was decided to use a bitfield because using a plain u32 with +mask/shift operations resulted in uncomprehensible code. + +Co-developed-by: John Ogness +Signed-off-by: John Ogness +Signed-off-by: Thomas Gleixner (Intel) +Reviewed-by: Petr Mladek +Signed-off-by: Petr Mladek +Link: https://lore.kernel.org/r/20230916192007.608398-2-john.ogness@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/console.h | 31 ++++++++++++++++++++ + kernel/printk/Makefile | 2 - + kernel/printk/internal.h | 8 +++++ + kernel/printk/nbcon.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++ + kernel/printk/printk.c | 13 ++++++-- + 5 files changed, 120 insertions(+), 4 deletions(-) + create mode 100644 kernel/printk/nbcon.c + +--- a/include/linux/console.h ++++ b/include/linux/console.h +@@ -156,6 +156,8 @@ static inline int con_debug_leave(void) + * /dev/kmesg which requires a larger output buffer. + * @CON_SUSPENDED: Indicates if a console is suspended. If true, the + * printing callbacks must not be called. ++ * @CON_NBCON: Console can operate outside of the legacy style console_lock ++ * constraints. + */ + enum cons_flags { + CON_PRINTBUFFER = BIT(0), +@@ -166,9 +168,33 @@ enum cons_flags { + CON_BRL = BIT(5), + CON_EXTENDED = BIT(6), + CON_SUSPENDED = BIT(7), ++ CON_NBCON = BIT(8), + }; + + /** ++ * struct nbcon_state - console state for nbcon consoles ++ * @atom: Compound of the state fields for atomic operations ++ * ++ * To be used for reading and preparing of the value stored in the nbcon ++ * state variable @console::nbcon_state. ++ */ ++struct nbcon_state { ++ union { ++ unsigned int atom; ++ struct { ++ }; ++ }; ++}; ++ ++/* ++ * The nbcon_state struct is used to easily create and interpret values that ++ * are stored in the @console::nbcon_state variable. Ensure this struct stays ++ * within the size boundaries of the atomic variable's underlying type in ++ * order to avoid any accidental truncation. ++ */ ++static_assert(sizeof(struct nbcon_state) <= sizeof(int)); ++ ++/** + * struct console - The console descriptor structure + * @name: The name of the console driver + * @write: Write callback to output messages (Optional) +@@ -187,6 +213,8 @@ enum cons_flags { + * @dropped: Number of unreported dropped ringbuffer records + * @data: Driver private data + * @node: hlist node for the console list ++ * ++ * @nbcon_state: State for nbcon consoles + */ + struct console { + char name[16]; +@@ -206,6 +234,9 @@ struct console { + unsigned long dropped; + void *data; + struct hlist_node node; ++ ++ /* nbcon console specific members */ ++ atomic_t __private nbcon_state; + }; + + #ifdef CONFIG_LOCKDEP +--- a/kernel/printk/Makefile ++++ b/kernel/printk/Makefile +@@ -1,6 +1,6 @@ + # SPDX-License-Identifier: GPL-2.0-only + obj-y = printk.o +-obj-$(CONFIG_PRINTK) += printk_safe.o ++obj-$(CONFIG_PRINTK) += printk_safe.o nbcon.o + obj-$(CONFIG_A11Y_BRAILLE_CONSOLE) += braille.o + obj-$(CONFIG_PRINTK_INDEX) += index.o + +--- a/kernel/printk/internal.h ++++ b/kernel/printk/internal.h +@@ -3,6 +3,7 @@ + * internal.h - printk internal definitions + */ + #include ++#include + + #if defined(CONFIG_PRINTK) && defined(CONFIG_SYSCTL) + void __init printk_sysctl_init(void); +@@ -61,6 +62,10 @@ void defer_console_output(void); + + u16 printk_parse_prefix(const char *text, int *level, + enum printk_info_flags *flags); ++ ++void nbcon_init(struct console *con); ++void nbcon_cleanup(struct console *con); ++ + #else + + #define PRINTK_PREFIX_MAX 0 +@@ -76,6 +81,9 @@ u16 printk_parse_prefix(const char *text + #define printk_safe_exit_irqrestore(flags) local_irq_restore(flags) + + static inline bool printk_percpu_data_ready(void) { return false; } ++static inline void nbcon_init(struct console *con) { } ++static inline void nbcon_cleanup(struct console *con) { } ++ + #endif /* CONFIG_PRINTK */ + + /** +--- /dev/null ++++ b/kernel/printk/nbcon.c +@@ -0,0 +1,70 @@ ++// SPDX-License-Identifier: GPL-2.0-only ++// Copyright (C) 2022 Linutronix GmbH, John Ogness ++// Copyright (C) 2022 Intel, Thomas Gleixner ++ ++#include ++#include ++#include "internal.h" ++/* ++ * Printk console printing implementation for consoles which does not depend ++ * on the legacy style console_lock mechanism. ++ */ ++ ++/** ++ * nbcon_state_set - Helper function to set the console state ++ * @con: Console to update ++ * @new: The new state to write ++ * ++ * Only to be used when the console is not yet or no longer visible in the ++ * system. Otherwise use nbcon_state_try_cmpxchg(). ++ */ ++static inline void nbcon_state_set(struct console *con, struct nbcon_state *new) ++{ ++ atomic_set(&ACCESS_PRIVATE(con, nbcon_state), new->atom); ++} ++ ++/** ++ * nbcon_state_read - Helper function to read the console state ++ * @con: Console to read ++ * @state: The state to store the result ++ */ ++static inline void nbcon_state_read(struct console *con, struct nbcon_state *state) ++{ ++ state->atom = atomic_read(&ACCESS_PRIVATE(con, nbcon_state)); ++} ++ ++/** ++ * nbcon_state_try_cmpxchg() - Helper function for atomic_try_cmpxchg() on console state ++ * @con: Console to update ++ * @cur: Old/expected state ++ * @new: New state ++ * ++ * Return: True on success. False on fail and @cur is updated. ++ */ ++static inline bool nbcon_state_try_cmpxchg(struct console *con, struct nbcon_state *cur, ++ struct nbcon_state *new) ++{ ++ return atomic_try_cmpxchg(&ACCESS_PRIVATE(con, nbcon_state), &cur->atom, new->atom); ++} ++ ++/** ++ * nbcon_init - Initialize the nbcon console specific data ++ * @con: Console to initialize ++ */ ++void nbcon_init(struct console *con) ++{ ++ struct nbcon_state state = { }; ++ ++ nbcon_state_set(con, &state); ++} ++ ++/** ++ * nbcon_cleanup - Cleanup the nbcon console specific data ++ * @con: Console to cleanup ++ */ ++void nbcon_cleanup(struct console *con) ++{ ++ struct nbcon_state state = { }; ++ ++ nbcon_state_set(con, &state); ++} +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -3326,9 +3326,10 @@ static void try_enable_default_console(s + newcon->flags |= CON_CONSDEV; + } + +-#define con_printk(lvl, con, fmt, ...) \ +- printk(lvl pr_fmt("%sconsole [%s%d] " fmt), \ +- (con->flags & CON_BOOT) ? "boot" : "", \ ++#define con_printk(lvl, con, fmt, ...) \ ++ printk(lvl pr_fmt("%s%sconsole [%s%d] " fmt), \ ++ (con->flags & CON_NBCON) ? "" : "legacy ", \ ++ (con->flags & CON_BOOT) ? "boot" : "", \ + con->name, con->index, ##__VA_ARGS__) + + static void console_init_seq(struct console *newcon, bool bootcon_registered) +@@ -3488,6 +3489,9 @@ void register_console(struct console *ne + newcon->dropped = 0; + console_init_seq(newcon, bootcon_registered); + ++ if (newcon->flags & CON_NBCON) ++ nbcon_init(newcon); ++ + /* + * Put this console in the list - keep the + * preferred driver at the head of the list. +@@ -3579,6 +3583,9 @@ static int unregister_console_locked(str + */ + synchronize_srcu(&console_srcu); + ++ if (console->flags & CON_NBCON) ++ nbcon_cleanup(console); ++ + console_sysfs_notify(); + + if (console->exit) diff --git a/debian/patches-rt/0076-printk-nbcon-Add-acquire-release-logic.patch b/debian/patches-rt/0076-printk-nbcon-Add-acquire-release-logic.patch new file mode 100644 index 000000000..271837903 --- /dev/null +++ b/debian/patches-rt/0076-printk-nbcon-Add-acquire-release-logic.patch @@ -0,0 +1,705 @@ +From: Thomas Gleixner +Date: Sat, 16 Sep 2023 21:26:01 +0206 +Subject: [PATCH 076/134] printk: nbcon: Add acquire/release logic +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Add per console acquire/release functionality. + +The state of the console is maintained in the "nbcon_state" atomic +variable. + +The console is locked when: + + - The 'prio' field contains the priority of the context that owns the + console. Only higher priority contexts are allowed to take over the + lock. A value of 0 (NBCON_PRIO_NONE) means the console is not locked. + + - The 'cpu' field denotes on which CPU the console is locked. It is used + to prevent busy waiting on the same CPU. Also it informs the lock owner + that it has lost the lock in a more complex scenario when the lock was + taken over by a higher priority context, released, and taken on another + CPU with the same priority as the interrupted owner. + +The acquire mechanism uses a few more fields: + + - The 'req_prio' field is used by the handover approach to make the + current owner aware that there is a context with a higher priority + waiting for the friendly handover. + + - The 'unsafe' field allows to take over the console in a safe way in the + middle of emitting a message. The field is set only when accessing some + shared resources or when the console device is manipulated. It can be + cleared, for example, after emitting one character when the console + device is in a consistent state. + + - The 'unsafe_takeover' field is set when a hostile takeover took the + console in an unsafe state. The console will stay in the unsafe state + until re-initialized. + +The acquire mechanism uses three approaches: + + 1) Direct acquire when the console is not owned or is owned by a lower + priority context and is in a safe state. + + 2) Friendly handover mechanism uses a request/grant handshake. It is used + when the current owner has lower priority and the console is in an + unsafe state. + + The requesting context: + + a) Sets its priority into the 'req_prio' field. + + b) Waits (with a timeout) for the owning context to unlock the + console. + + c) Takes the lock and clears the 'req_prio' field. + + The owning context: + + a) Observes the 'req_prio' field set on exit from the unsafe + console state. + + b) Gives up console ownership by clearing the 'prio' field. + + 3) Unsafe hostile takeover allows to take over the lock even when the + console is an unsafe state. It is used only in panic() by the final + attempt to flush consoles in a try and hope mode. + + Note that separate record buffers are used in panic(). As a result, + the messages can be read and formatted without any risk even after + using the hostile takeover in unsafe state. + +The release function simply clears the 'prio' field. + +All operations on @console::nbcon_state are atomic cmpxchg based to +handle concurrency. + +The acquire/release functions implement only minimal policies: + + - Preference for higher priority contexts. + - Protection of the panic CPU. + +All other policy decisions must be made at the call sites: + + - What is marked as an unsafe section. + - Whether to spin-wait if there is already an owner and the console is + in an unsafe state. + - Whether to attempt an unsafe hostile takeover. + +The design allows to implement the well known: + + acquire() + output_one_printk_record() + release() + +The output of one printk record might be interrupted with a higher priority +context. The new owner is supposed to reprint the entire interrupted record +from scratch. + +Co-developed-by: John Ogness +Signed-off-by: John Ogness +Signed-off-by: Thomas Gleixner (Intel) +Signed-off-by: Petr Mladek +Link: https://lore.kernel.org/r/20230916192007.608398-3-john.ogness@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/console.h | 56 +++++ + kernel/printk/nbcon.c | 497 ++++++++++++++++++++++++++++++++++++++++++++++++ + 2 files changed, 553 insertions(+) + +--- a/include/linux/console.h ++++ b/include/linux/console.h +@@ -175,13 +175,29 @@ enum cons_flags { + * struct nbcon_state - console state for nbcon consoles + * @atom: Compound of the state fields for atomic operations + * ++ * @req_prio: The priority of a handover request ++ * @prio: The priority of the current owner ++ * @unsafe: Console is busy in a non takeover region ++ * @unsafe_takeover: A hostile takeover in an unsafe state happened in the ++ * past. The console cannot be safe until re-initialized. ++ * @cpu: The CPU on which the owner runs ++ * + * To be used for reading and preparing of the value stored in the nbcon + * state variable @console::nbcon_state. ++ * ++ * The @prio and @req_prio fields are particularly important to allow ++ * spin-waiting to timeout and give up without the risk of a waiter being ++ * assigned the lock after giving up. + */ + struct nbcon_state { + union { + unsigned int atom; + struct { ++ unsigned int prio : 2; ++ unsigned int req_prio : 2; ++ unsigned int unsafe : 1; ++ unsigned int unsafe_takeover : 1; ++ unsigned int cpu : 24; + }; + }; + }; +@@ -195,6 +211,46 @@ struct nbcon_state { + static_assert(sizeof(struct nbcon_state) <= sizeof(int)); + + /** ++ * nbcon_prio - console owner priority for nbcon consoles ++ * @NBCON_PRIO_NONE: Unused ++ * @NBCON_PRIO_NORMAL: Normal (non-emergency) usage ++ * @NBCON_PRIO_EMERGENCY: Emergency output (WARN/OOPS...) ++ * @NBCON_PRIO_PANIC: Panic output ++ * @NBCON_PRIO_MAX: The number of priority levels ++ * ++ * A higher priority context can takeover the console when it is ++ * in the safe state. The final attempt to flush consoles in panic() ++ * can be allowed to do so even in an unsafe state (Hope and pray). ++ */ ++enum nbcon_prio { ++ NBCON_PRIO_NONE = 0, ++ NBCON_PRIO_NORMAL, ++ NBCON_PRIO_EMERGENCY, ++ NBCON_PRIO_PANIC, ++ NBCON_PRIO_MAX, ++}; ++ ++struct console; ++ ++/** ++ * struct nbcon_context - Context for console acquire/release ++ * @console: The associated console ++ * @spinwait_max_us: Limit for spin-wait acquire ++ * @prio: Priority of the context ++ * @allow_unsafe_takeover: Allow performing takeover even if unsafe. Can ++ * be used only with NBCON_PRIO_PANIC @prio. It ++ * might cause a system freeze when the console ++ * is used later. ++ */ ++struct nbcon_context { ++ /* members set by caller */ ++ struct console *console; ++ unsigned int spinwait_max_us; ++ enum nbcon_prio prio; ++ unsigned int allow_unsafe_takeover : 1; ++}; ++ ++/** + * struct console - The console descriptor structure + * @name: The name of the console driver + * @write: Write callback to output messages (Optional) +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -4,10 +4,98 @@ + + #include + #include ++#include + #include "internal.h" + /* + * Printk console printing implementation for consoles which does not depend + * on the legacy style console_lock mechanism. ++ * ++ * The state of the console is maintained in the "nbcon_state" atomic ++ * variable. ++ * ++ * The console is locked when: ++ * ++ * - The 'prio' field contains the priority of the context that owns the ++ * console. Only higher priority contexts are allowed to take over the ++ * lock. A value of 0 (NBCON_PRIO_NONE) means the console is not locked. ++ * ++ * - The 'cpu' field denotes on which CPU the console is locked. It is used ++ * to prevent busy waiting on the same CPU. Also it informs the lock owner ++ * that it has lost the lock in a more complex scenario when the lock was ++ * taken over by a higher priority context, released, and taken on another ++ * CPU with the same priority as the interrupted owner. ++ * ++ * The acquire mechanism uses a few more fields: ++ * ++ * - The 'req_prio' field is used by the handover approach to make the ++ * current owner aware that there is a context with a higher priority ++ * waiting for the friendly handover. ++ * ++ * - The 'unsafe' field allows to take over the console in a safe way in the ++ * middle of emitting a message. The field is set only when accessing some ++ * shared resources or when the console device is manipulated. It can be ++ * cleared, for example, after emitting one character when the console ++ * device is in a consistent state. ++ * ++ * - The 'unsafe_takeover' field is set when a hostile takeover took the ++ * console in an unsafe state. The console will stay in the unsafe state ++ * until re-initialized. ++ * ++ * The acquire mechanism uses three approaches: ++ * ++ * 1) Direct acquire when the console is not owned or is owned by a lower ++ * priority context and is in a safe state. ++ * ++ * 2) Friendly handover mechanism uses a request/grant handshake. It is used ++ * when the current owner has lower priority and the console is in an ++ * unsafe state. ++ * ++ * The requesting context: ++ * ++ * a) Sets its priority into the 'req_prio' field. ++ * ++ * b) Waits (with a timeout) for the owning context to unlock the ++ * console. ++ * ++ * c) Takes the lock and clears the 'req_prio' field. ++ * ++ * The owning context: ++ * ++ * a) Observes the 'req_prio' field set on exit from the unsafe ++ * console state. ++ * ++ * b) Gives up console ownership by clearing the 'prio' field. ++ * ++ * 3) Unsafe hostile takeover allows to take over the lock even when the ++ * console is an unsafe state. It is used only in panic() by the final ++ * attempt to flush consoles in a try and hope mode. ++ * ++ * The release function simply clears the 'prio' field. ++ * ++ * All operations on @console::nbcon_state are atomic cmpxchg based to ++ * handle concurrency. ++ * ++ * The acquire/release functions implement only minimal policies: ++ * ++ * - Preference for higher priority contexts. ++ * - Protection of the panic CPU. ++ * ++ * All other policy decisions must be made at the call sites: ++ * ++ * - What is marked as an unsafe section. ++ * - Whether to spin-wait if there is already an owner and the console is ++ * in an unsafe state. ++ * - Whether to attempt an unsafe hostile takeover. ++ * ++ * The design allows to implement the well known: ++ * ++ * acquire() ++ * output_one_printk_record() ++ * release() ++ * ++ * The output of one printk record might be interrupted with a higher priority ++ * context. The new owner is supposed to reprint the entire interrupted record ++ * from scratch. + */ + + /** +@@ -48,6 +136,415 @@ static inline bool nbcon_state_try_cmpxc + } + + /** ++ * nbcon_context_try_acquire_direct - Try to acquire directly ++ * @ctxt: The context of the caller ++ * @cur: The current console state ++ * ++ * Acquire the console when it is released. Also acquire the console when ++ * the current owner has a lower priority and the console is in a safe state. ++ * ++ * Return: 0 on success. Otherwise, an error code on failure. Also @cur ++ * is updated to the latest state when failed to modify it. ++ * ++ * Errors: ++ * ++ * -EPERM: A panic is in progress and this is not the panic CPU. ++ * Or the current owner or waiter has the same or higher ++ * priority. No acquire method can be successful in ++ * this case. ++ * ++ * -EBUSY: The current owner has a lower priority but the console ++ * in an unsafe state. The caller should try using ++ * the handover acquire method. ++ */ ++static int nbcon_context_try_acquire_direct(struct nbcon_context *ctxt, ++ struct nbcon_state *cur) ++{ ++ unsigned int cpu = smp_processor_id(); ++ struct console *con = ctxt->console; ++ struct nbcon_state new; ++ ++ do { ++ if (other_cpu_in_panic()) ++ return -EPERM; ++ ++ if (ctxt->prio <= cur->prio || ctxt->prio <= cur->req_prio) ++ return -EPERM; ++ ++ if (cur->unsafe) ++ return -EBUSY; ++ ++ /* ++ * The console should never be safe for a direct acquire ++ * if an unsafe hostile takeover has ever happened. ++ */ ++ WARN_ON_ONCE(cur->unsafe_takeover); ++ ++ new.atom = cur->atom; ++ new.prio = ctxt->prio; ++ new.req_prio = NBCON_PRIO_NONE; ++ new.unsafe = cur->unsafe_takeover; ++ new.cpu = cpu; ++ ++ } while (!nbcon_state_try_cmpxchg(con, cur, &new)); ++ ++ return 0; ++} ++ ++static bool nbcon_waiter_matches(struct nbcon_state *cur, int expected_prio) ++{ ++ /* ++ * The request context is well defined by the @req_prio because: ++ * ++ * - Only a context with a higher priority can take over the request. ++ * - There are only three priorities. ++ * - Only one CPU is allowed to request PANIC priority. ++ * - Lower priorities are ignored during panic() until reboot. ++ * ++ * As a result, the following scenario is *not* possible: ++ * ++ * 1. Another context with a higher priority directly takes ownership. ++ * 2. The higher priority context releases the ownership. ++ * 3. A lower priority context takes the ownership. ++ * 4. Another context with the same priority as this context ++ * creates a request and starts waiting. ++ */ ++ ++ return (cur->req_prio == expected_prio); ++} ++ ++/** ++ * nbcon_context_try_acquire_requested - Try to acquire after having ++ * requested a handover ++ * @ctxt: The context of the caller ++ * @cur: The current console state ++ * ++ * This is a helper function for nbcon_context_try_acquire_handover(). ++ * It is called when the console is in an unsafe state. The current ++ * owner will release the console on exit from the unsafe region. ++ * ++ * Return: 0 on success and @cur is updated to the new console state. ++ * Otherwise an error code on failure. ++ * ++ * Errors: ++ * ++ * -EPERM: A panic is in progress and this is not the panic CPU ++ * or this context is no longer the waiter. ++ * ++ * -EBUSY: The console is still locked. The caller should ++ * continue waiting. ++ * ++ * Note: The caller must still remove the request when an error has occurred ++ * except when this context is no longer the waiter. ++ */ ++static int nbcon_context_try_acquire_requested(struct nbcon_context *ctxt, ++ struct nbcon_state *cur) ++{ ++ unsigned int cpu = smp_processor_id(); ++ struct console *con = ctxt->console; ++ struct nbcon_state new; ++ ++ /* Note that the caller must still remove the request! */ ++ if (other_cpu_in_panic()) ++ return -EPERM; ++ ++ /* ++ * Note that the waiter will also change if there was an unsafe ++ * hostile takeover. ++ */ ++ if (!nbcon_waiter_matches(cur, ctxt->prio)) ++ return -EPERM; ++ ++ /* If still locked, caller should continue waiting. */ ++ if (cur->prio != NBCON_PRIO_NONE) ++ return -EBUSY; ++ ++ /* ++ * The previous owner should have never released ownership ++ * in an unsafe region. ++ */ ++ WARN_ON_ONCE(cur->unsafe); ++ ++ new.atom = cur->atom; ++ new.prio = ctxt->prio; ++ new.req_prio = NBCON_PRIO_NONE; ++ new.unsafe = cur->unsafe_takeover; ++ new.cpu = cpu; ++ ++ if (!nbcon_state_try_cmpxchg(con, cur, &new)) { ++ /* ++ * The acquire could fail only when it has been taken ++ * over by a higher priority context. ++ */ ++ WARN_ON_ONCE(nbcon_waiter_matches(cur, ctxt->prio)); ++ return -EPERM; ++ } ++ ++ /* Handover success. This context now owns the console. */ ++ return 0; ++} ++ ++/** ++ * nbcon_context_try_acquire_handover - Try to acquire via handover ++ * @ctxt: The context of the caller ++ * @cur: The current console state ++ * ++ * The function must be called only when the context has higher priority ++ * than the current owner and the console is in an unsafe state. ++ * It is the case when nbcon_context_try_acquire_direct() returns -EBUSY. ++ * ++ * The function sets "req_prio" field to make the current owner aware of ++ * the request. Then it waits until the current owner releases the console, ++ * or an even higher context takes over the request, or timeout expires. ++ * ++ * The current owner checks the "req_prio" field on exit from the unsafe ++ * region and releases the console. It does not touch the "req_prio" field ++ * so that the console stays reserved for the waiter. ++ * ++ * Return: 0 on success. Otherwise, an error code on failure. Also @cur ++ * is updated to the latest state when failed to modify it. ++ * ++ * Errors: ++ * ++ * -EPERM: A panic is in progress and this is not the panic CPU. ++ * Or a higher priority context has taken over the ++ * console or the handover request. ++ * ++ * -EBUSY: The current owner is on the same CPU so that the hand ++ * shake could not work. Or the current owner is not ++ * willing to wait (zero timeout). Or the console does ++ * not enter the safe state before timeout passed. The ++ * caller might still use the unsafe hostile takeover ++ * when allowed. ++ * ++ * -EAGAIN: @cur has changed when creating the handover request. ++ * The caller should retry with direct acquire. ++ */ ++static int nbcon_context_try_acquire_handover(struct nbcon_context *ctxt, ++ struct nbcon_state *cur) ++{ ++ unsigned int cpu = smp_processor_id(); ++ struct console *con = ctxt->console; ++ struct nbcon_state new; ++ int timeout; ++ int request_err = -EBUSY; ++ ++ /* ++ * Check that the handover is called when the direct acquire failed ++ * with -EBUSY. ++ */ ++ WARN_ON_ONCE(ctxt->prio <= cur->prio || ctxt->prio <= cur->req_prio); ++ WARN_ON_ONCE(!cur->unsafe); ++ ++ /* Handover is not possible on the same CPU. */ ++ if (cur->cpu == cpu) ++ return -EBUSY; ++ ++ /* ++ * Console stays unsafe after an unsafe takeover until re-initialized. ++ * Waiting is not going to help in this case. ++ */ ++ if (cur->unsafe_takeover) ++ return -EBUSY; ++ ++ /* Is the caller willing to wait? */ ++ if (ctxt->spinwait_max_us == 0) ++ return -EBUSY; ++ ++ /* ++ * Setup a request for the handover. The caller should try to acquire ++ * the console directly when the current state has been modified. ++ */ ++ new.atom = cur->atom; ++ new.req_prio = ctxt->prio; ++ if (!nbcon_state_try_cmpxchg(con, cur, &new)) ++ return -EAGAIN; ++ ++ cur->atom = new.atom; ++ ++ /* Wait until there is no owner and then acquire the console. */ ++ for (timeout = ctxt->spinwait_max_us; timeout >= 0; timeout--) { ++ /* On successful acquire, this request is cleared. */ ++ request_err = nbcon_context_try_acquire_requested(ctxt, cur); ++ if (!request_err) ++ return 0; ++ ++ /* ++ * If the acquire should be aborted, it must be ensured ++ * that the request is removed before returning to caller. ++ */ ++ if (request_err == -EPERM) ++ break; ++ ++ udelay(1); ++ ++ /* Re-read the state because some time has passed. */ ++ nbcon_state_read(con, cur); ++ } ++ ++ /* Timed out or aborted. Carefully remove handover request. */ ++ do { ++ /* ++ * No need to remove request if there is a new waiter. This ++ * can only happen if a higher priority context has taken over ++ * the console or the handover request. ++ */ ++ if (!nbcon_waiter_matches(cur, ctxt->prio)) ++ return -EPERM; ++ ++ /* Unset request for handover. */ ++ new.atom = cur->atom; ++ new.req_prio = NBCON_PRIO_NONE; ++ if (nbcon_state_try_cmpxchg(con, cur, &new)) { ++ /* ++ * Request successfully unset. Report failure of ++ * acquiring via handover. ++ */ ++ cur->atom = new.atom; ++ return request_err; ++ } ++ ++ /* ++ * Unable to remove request. Try to acquire in case ++ * the owner has released the lock. ++ */ ++ } while (nbcon_context_try_acquire_requested(ctxt, cur)); ++ ++ /* Lucky timing. The acquire succeeded while removing the request. */ ++ return 0; ++} ++ ++/** ++ * nbcon_context_try_acquire_hostile - Acquire via unsafe hostile takeover ++ * @ctxt: The context of the caller ++ * @cur: The current console state ++ * ++ * Acquire the console even in the unsafe state. ++ * ++ * It can be permitted by setting the 'allow_unsafe_takeover' field only ++ * by the final attempt to flush messages in panic(). ++ * ++ * Return: 0 on success. -EPERM when not allowed by the context. ++ */ ++static int nbcon_context_try_acquire_hostile(struct nbcon_context *ctxt, ++ struct nbcon_state *cur) ++{ ++ unsigned int cpu = smp_processor_id(); ++ struct console *con = ctxt->console; ++ struct nbcon_state new; ++ ++ if (!ctxt->allow_unsafe_takeover) ++ return -EPERM; ++ ++ /* Ensure caller is allowed to perform unsafe hostile takeovers. */ ++ if (WARN_ON_ONCE(ctxt->prio != NBCON_PRIO_PANIC)) ++ return -EPERM; ++ ++ /* ++ * Check that try_acquire_direct() and try_acquire_handover() returned ++ * -EBUSY in the right situation. ++ */ ++ WARN_ON_ONCE(ctxt->prio <= cur->prio || ctxt->prio <= cur->req_prio); ++ WARN_ON_ONCE(cur->unsafe != true); ++ ++ do { ++ new.atom = cur->atom; ++ new.cpu = cpu; ++ new.prio = ctxt->prio; ++ new.unsafe |= cur->unsafe_takeover; ++ new.unsafe_takeover |= cur->unsafe; ++ ++ } while (!nbcon_state_try_cmpxchg(con, cur, &new)); ++ ++ return 0; ++} ++ ++/** ++ * nbcon_context_try_acquire - Try to acquire nbcon console ++ * @ctxt: The context of the caller ++ * ++ * Return: True if the console was acquired. False otherwise. ++ * ++ * If the caller allowed an unsafe hostile takeover, on success the ++ * caller should check the current console state to see if it is ++ * in an unsafe state. Otherwise, on success the caller may assume ++ * the console is not in an unsafe state. ++ */ ++__maybe_unused ++static bool nbcon_context_try_acquire(struct nbcon_context *ctxt) ++{ ++ struct console *con = ctxt->console; ++ struct nbcon_state cur; ++ int err; ++ ++ nbcon_state_read(con, &cur); ++try_again: ++ err = nbcon_context_try_acquire_direct(ctxt, &cur); ++ if (err != -EBUSY) ++ goto out; ++ ++ err = nbcon_context_try_acquire_handover(ctxt, &cur); ++ if (err == -EAGAIN) ++ goto try_again; ++ if (err != -EBUSY) ++ goto out; ++ ++ err = nbcon_context_try_acquire_hostile(ctxt, &cur); ++out: ++ return !err; ++} ++ ++static bool nbcon_owner_matches(struct nbcon_state *cur, int expected_cpu, ++ int expected_prio) ++{ ++ /* ++ * Since consoles can only be acquired by higher priorities, ++ * owning contexts are uniquely identified by @prio. However, ++ * since contexts can unexpectedly lose ownership, it is ++ * possible that later another owner appears with the same ++ * priority. For this reason @cpu is also needed. ++ */ ++ ++ if (cur->prio != expected_prio) ++ return false; ++ ++ if (cur->cpu != expected_cpu) ++ return false; ++ ++ return true; ++} ++ ++/** ++ * nbcon_context_release - Release the console ++ * @ctxt: The nbcon context from nbcon_context_try_acquire() ++ */ ++__maybe_unused ++static void nbcon_context_release(struct nbcon_context *ctxt) ++{ ++ unsigned int cpu = smp_processor_id(); ++ struct console *con = ctxt->console; ++ struct nbcon_state cur; ++ struct nbcon_state new; ++ ++ nbcon_state_read(con, &cur); ++ ++ do { ++ if (!nbcon_owner_matches(&cur, cpu, ctxt->prio)) ++ return; ++ ++ new.atom = cur.atom; ++ new.prio = NBCON_PRIO_NONE; ++ ++ /* ++ * If @unsafe_takeover is set, it is kept set so that ++ * the state remains permanently unsafe. ++ */ ++ new.unsafe |= cur.unsafe_takeover; ++ ++ } while (!nbcon_state_try_cmpxchg(con, &cur, &new)); ++} ++ ++/** + * nbcon_init - Initialize the nbcon console specific data + * @con: Console to initialize + */ diff --git a/debian/patches-rt/0077-printk-Make-static-printk-buffers-available-to-nbcon.patch b/debian/patches-rt/0077-printk-Make-static-printk-buffers-available-to-nbcon.patch new file mode 100644 index 000000000..f3fbb6a82 --- /dev/null +++ b/debian/patches-rt/0077-printk-Make-static-printk-buffers-available-to-nbcon.patch @@ -0,0 +1,65 @@ +From: John Ogness +Date: Sat, 16 Sep 2023 21:26:02 +0206 +Subject: [PATCH 077/134] printk: Make static printk buffers available to nbcon +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +The nbcon boot consoles also need printk buffers that are available +very early. Since the nbcon boot consoles will also be serialized +by the console_lock, they can use the same static printk buffers +that the legacy consoles are using. + +Make the legacy static printk buffers available outside of printk.c +so they can be used by nbcon.c. + +Signed-off-by: John Ogness +Reviewed-by: Petr Mladek +Signed-off-by: Petr Mladek +Link: https://lore.kernel.org/r/20230916192007.608398-4-john.ogness@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/internal.h | 2 ++ + kernel/printk/printk.c | 13 +++++++++---- + 2 files changed, 11 insertions(+), 4 deletions(-) + +--- a/kernel/printk/internal.h ++++ b/kernel/printk/internal.h +@@ -86,6 +86,8 @@ static inline void nbcon_cleanup(struct + + #endif /* CONFIG_PRINTK */ + ++extern struct printk_buffers printk_shared_pbufs; ++ + /** + * struct printk_buffers - Buffers to read/format/output printk messages. + * @outbuf: After formatting, contains text to output. +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -2847,6 +2847,13 @@ static bool printk_get_next_message(stru + } + + /* ++ * Used as the printk buffers for non-panic, serialized console printing. ++ * This is for legacy (!CON_NBCON) as well as all boot (CON_BOOT) consoles. ++ * Its usage requires the console_lock held. ++ */ ++struct printk_buffers printk_shared_pbufs; ++ ++/* + * Print one record for the given console. The record printed is whatever + * record is the next available record for the given console. + * +@@ -2863,12 +2870,10 @@ static bool printk_get_next_message(stru + */ + static bool console_emit_next_record(struct console *con, bool *handover, int cookie) + { +- static struct printk_buffers pbufs; +- + bool is_extended = console_srcu_read_flags(con) & CON_EXTENDED; +- char *outbuf = &pbufs.outbuf[0]; ++ char *outbuf = &printk_shared_pbufs.outbuf[0]; + struct printk_message pmsg = { +- .pbufs = &pbufs, ++ .pbufs = &printk_shared_pbufs, + }; + unsigned long flags; + diff --git a/debian/patches-rt/0078-printk-nbcon-Add-buffer-management.patch b/debian/patches-rt/0078-printk-nbcon-Add-buffer-management.patch new file mode 100644 index 000000000..ea96abd7e --- /dev/null +++ b/debian/patches-rt/0078-printk-nbcon-Add-buffer-management.patch @@ -0,0 +1,311 @@ +From: Thomas Gleixner +Date: Sat, 16 Sep 2023 21:26:03 +0206 +Subject: [PATCH 078/134] printk: nbcon: Add buffer management +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +In case of hostile takeovers it must be ensured that the previous +owner cannot scribble over the output buffer of the emergency/panic +context. This is achieved by: + + - Adding a global output buffer instance for the panic context. + This is the only situation where hostile takeovers can occur and + there is always at most 1 panic context. + + - Allocating an output buffer per non-boot console upon console + registration. This buffer is used by the console owner when not + in panic context. (For boot consoles, the existing shared global + legacy output buffer is used instead. Boot console printing will + be synchronized with legacy console printing.) + + - Choosing the appropriate buffer is handled in the acquire/release + functions. + +Co-developed-by: John Ogness +Signed-off-by: John Ogness +Signed-off-by: Thomas Gleixner (Intel) +Reviewed-by: Petr Mladek +Signed-off-by: Petr Mladek +Link: https://lore.kernel.org/r/20230916192007.608398-5-john.ogness@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/console.h | 7 ++++ + kernel/printk/internal.h | 12 ++++++- + kernel/printk/nbcon.c | 73 +++++++++++++++++++++++++++++++++++++++++++---- + kernel/printk/printk.c | 22 +++++++++----- + 4 files changed, 99 insertions(+), 15 deletions(-) + +--- a/include/linux/console.h ++++ b/include/linux/console.h +@@ -231,6 +231,7 @@ enum nbcon_prio { + }; + + struct console; ++struct printk_buffers; + + /** + * struct nbcon_context - Context for console acquire/release +@@ -241,6 +242,7 @@ struct console; + * be used only with NBCON_PRIO_PANIC @prio. It + * might cause a system freeze when the console + * is used later. ++ * @pbufs: Pointer to the text buffer for this context + */ + struct nbcon_context { + /* members set by caller */ +@@ -248,6 +250,9 @@ struct nbcon_context { + unsigned int spinwait_max_us; + enum nbcon_prio prio; + unsigned int allow_unsafe_takeover : 1; ++ ++ /* members set by acquire */ ++ struct printk_buffers *pbufs; + }; + + /** +@@ -271,6 +276,7 @@ struct nbcon_context { + * @node: hlist node for the console list + * + * @nbcon_state: State for nbcon consoles ++ * @pbufs: Pointer to nbcon private buffer + */ + struct console { + char name[16]; +@@ -293,6 +299,7 @@ struct console { + + /* nbcon console specific members */ + atomic_t __private nbcon_state; ++ struct printk_buffers *pbufs; + }; + + #ifdef CONFIG_LOCKDEP +--- a/kernel/printk/internal.h ++++ b/kernel/printk/internal.h +@@ -13,6 +13,12 @@ int devkmsg_sysctl_set_loglvl(struct ctl + #define printk_sysctl_init() do { } while (0) + #endif + ++#define con_printk(lvl, con, fmt, ...) \ ++ printk(lvl pr_fmt("%s%sconsole [%s%d] " fmt), \ ++ (con->flags & CON_NBCON) ? "" : "legacy ", \ ++ (con->flags & CON_BOOT) ? "boot" : "", \ ++ con->name, con->index, ##__VA_ARGS__) ++ + #ifdef CONFIG_PRINTK + + #ifdef CONFIG_PRINTK_CALLER +@@ -63,8 +69,9 @@ void defer_console_output(void); + u16 printk_parse_prefix(const char *text, int *level, + enum printk_info_flags *flags); + ++bool nbcon_alloc(struct console *con); + void nbcon_init(struct console *con); +-void nbcon_cleanup(struct console *con); ++void nbcon_free(struct console *con); + + #else + +@@ -81,8 +88,9 @@ void nbcon_cleanup(struct console *con); + #define printk_safe_exit_irqrestore(flags) local_irq_restore(flags) + + static inline bool printk_percpu_data_ready(void) { return false; } ++static inline bool nbcon_alloc(struct console *con) { return false; } + static inline void nbcon_init(struct console *con) { } +-static inline void nbcon_cleanup(struct console *con) { } ++static inline void nbcon_free(struct console *con) { } + + #endif /* CONFIG_PRINTK */ + +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -5,6 +5,7 @@ + #include + #include + #include ++#include + #include "internal.h" + /* + * Printk console printing implementation for consoles which does not depend +@@ -70,6 +71,10 @@ + * console is an unsafe state. It is used only in panic() by the final + * attempt to flush consoles in a try and hope mode. + * ++ * Note that separate record buffers are used in panic(). As a result, ++ * the messages can be read and formatted without any risk even after ++ * using the hostile takeover in unsafe state. ++ * + * The release function simply clears the 'prio' field. + * + * All operations on @console::nbcon_state are atomic cmpxchg based to +@@ -459,6 +464,8 @@ static int nbcon_context_try_acquire_hos + return 0; + } + ++static struct printk_buffers panic_nbcon_pbufs; ++ + /** + * nbcon_context_try_acquire - Try to acquire nbcon console + * @ctxt: The context of the caller +@@ -473,6 +480,7 @@ static int nbcon_context_try_acquire_hos + __maybe_unused + static bool nbcon_context_try_acquire(struct nbcon_context *ctxt) + { ++ unsigned int cpu = smp_processor_id(); + struct console *con = ctxt->console; + struct nbcon_state cur; + int err; +@@ -491,7 +499,18 @@ static bool nbcon_context_try_acquire(st + + err = nbcon_context_try_acquire_hostile(ctxt, &cur); + out: +- return !err; ++ if (err) ++ return false; ++ ++ /* Acquire succeeded. */ ++ ++ /* Assign the appropriate buffer for this context. */ ++ if (atomic_read(&panic_cpu) == cpu) ++ ctxt->pbufs = &panic_nbcon_pbufs; ++ else ++ ctxt->pbufs = con->pbufs; ++ ++ return true; + } + + static bool nbcon_owner_matches(struct nbcon_state *cur, int expected_cpu, +@@ -530,7 +549,7 @@ static void nbcon_context_release(struct + + do { + if (!nbcon_owner_matches(&cur, cpu, ctxt->prio)) +- return; ++ break; + + new.atom = cur.atom; + new.prio = NBCON_PRIO_NONE; +@@ -542,26 +561,70 @@ static void nbcon_context_release(struct + new.unsafe |= cur.unsafe_takeover; + + } while (!nbcon_state_try_cmpxchg(con, &cur, &new)); ++ ++ ctxt->pbufs = NULL; ++} ++ ++/** ++ * nbcon_alloc - Allocate buffers needed by the nbcon console ++ * @con: Console to allocate buffers for ++ * ++ * Return: True on success. False otherwise and the console cannot ++ * be used. ++ * ++ * This is not part of nbcon_init() because buffer allocation must ++ * be performed earlier in the console registration process. ++ */ ++bool nbcon_alloc(struct console *con) ++{ ++ if (con->flags & CON_BOOT) { ++ /* ++ * Boot console printing is synchronized with legacy console ++ * printing, so boot consoles can share the same global printk ++ * buffers. ++ */ ++ con->pbufs = &printk_shared_pbufs; ++ } else { ++ con->pbufs = kmalloc(sizeof(*con->pbufs), GFP_KERNEL); ++ if (!con->pbufs) { ++ con_printk(KERN_ERR, con, "failed to allocate printing buffer\n"); ++ return false; ++ } ++ } ++ ++ return true; + } + + /** + * nbcon_init - Initialize the nbcon console specific data + * @con: Console to initialize ++ * ++ * nbcon_alloc() *must* be called and succeed before this function ++ * is called. + */ + void nbcon_init(struct console *con) + { + struct nbcon_state state = { }; + ++ /* nbcon_alloc() must have been called and successful! */ ++ BUG_ON(!con->pbufs); ++ + nbcon_state_set(con, &state); + } + + /** +- * nbcon_cleanup - Cleanup the nbcon console specific data +- * @con: Console to cleanup ++ * nbcon_free - Free and cleanup the nbcon console specific data ++ * @con: Console to free/cleanup nbcon data + */ +-void nbcon_cleanup(struct console *con) ++void nbcon_free(struct console *con) + { + struct nbcon_state state = { }; + + nbcon_state_set(con, &state); ++ ++ /* Boot consoles share global printk buffers. */ ++ if (!(con->flags & CON_BOOT)) ++ kfree(con->pbufs); ++ ++ con->pbufs = NULL; + } +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -3331,12 +3331,6 @@ static void try_enable_default_console(s + newcon->flags |= CON_CONSDEV; + } + +-#define con_printk(lvl, con, fmt, ...) \ +- printk(lvl pr_fmt("%s%sconsole [%s%d] " fmt), \ +- (con->flags & CON_NBCON) ? "" : "legacy ", \ +- (con->flags & CON_BOOT) ? "boot" : "", \ +- con->name, con->index, ##__VA_ARGS__) +- + static void console_init_seq(struct console *newcon, bool bootcon_registered) + { + struct console *con; +@@ -3450,6 +3444,15 @@ void register_console(struct console *ne + goto unlock; + } + ++ if (newcon->flags & CON_NBCON) { ++ /* ++ * Ensure the nbcon console buffers can be allocated ++ * before modifying any global data. ++ */ ++ if (!nbcon_alloc(newcon)) ++ goto unlock; ++ } ++ + /* + * See if we want to enable this console driver by default. + * +@@ -3477,8 +3480,11 @@ void register_console(struct console *ne + err = try_enable_preferred_console(newcon, false); + + /* printk() messages are not printed to the Braille console. */ +- if (err || newcon->flags & CON_BRL) ++ if (err || newcon->flags & CON_BRL) { ++ if (newcon->flags & CON_NBCON) ++ nbcon_free(newcon); + goto unlock; ++ } + + /* + * If we have a bootconsole, and are switching to a real console, +@@ -3589,7 +3595,7 @@ static int unregister_console_locked(str + synchronize_srcu(&console_srcu); + + if (console->flags & CON_NBCON) +- nbcon_cleanup(console); ++ nbcon_free(console); + + console_sysfs_notify(); + diff --git a/debian/patches-rt/0079-printk-nbcon-Add-ownership-state-functions.patch b/debian/patches-rt/0079-printk-nbcon-Add-ownership-state-functions.patch new file mode 100644 index 000000000..e26a5f332 --- /dev/null +++ b/debian/patches-rt/0079-printk-nbcon-Add-ownership-state-functions.patch @@ -0,0 +1,179 @@ +From: Thomas Gleixner +Date: Sat, 16 Sep 2023 21:26:04 +0206 +Subject: [PATCH 079/134] printk: nbcon: Add ownership state functions +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Provide functions that are related to the safe handover mechanism +and allow console drivers to dynamically specify unsafe regions: + + - nbcon_context_can_proceed() + + Invoked by a console owner to check whether a handover request + is pending or whether the console has been taken over by another + context. If a handover request is pending, this function will + also perform the handover, thus cancelling its own ownership. + + - nbcon_context_enter_unsafe()/nbcon_context_exit_unsafe() + + Invoked by a console owner to denote that the driver is about + to enter or leave a critical region where a take over is unsafe. + The exit variant is the point where the current owner releases + the lock for a higher priority context which asked for the + friendly handover. + + The unsafe state is stored in the console state and allows a + new context to make informed decisions whether to attempt a + takeover of such a console. The unsafe state is also available + to the driver so that it can make informed decisions about the + required actions and possibly take a special emergency path. + +Co-developed-by: John Ogness +Signed-off-by: John Ogness +Signed-off-by: Thomas Gleixner (Intel) +Reviewed-by: Petr Mladek +Signed-off-by: Petr Mladek +Link: https://lore.kernel.org/r/20230916192007.608398-6-john.ogness@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/nbcon.c | 123 +++++++++++++++++++++++++++++++++++++++++++++++++- + 1 file changed, 122 insertions(+), 1 deletion(-) + +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -537,7 +537,6 @@ static bool nbcon_owner_matches(struct n + * nbcon_context_release - Release the console + * @ctxt: The nbcon context from nbcon_context_try_acquire() + */ +-__maybe_unused + static void nbcon_context_release(struct nbcon_context *ctxt) + { + unsigned int cpu = smp_processor_id(); +@@ -566,6 +565,128 @@ static void nbcon_context_release(struct + } + + /** ++ * nbcon_context_can_proceed - Check whether ownership can proceed ++ * @ctxt: The nbcon context from nbcon_context_try_acquire() ++ * @cur: The current console state ++ * ++ * Return: True if this context still owns the console. False if ++ * ownership was handed over or taken. ++ * ++ * Must be invoked when entering the unsafe state to make sure that it still ++ * owns the lock. Also must be invoked when exiting the unsafe context ++ * to eventually free the lock for a higher priority context which asked ++ * for the friendly handover. ++ * ++ * It can be called inside an unsafe section when the console is just ++ * temporary in safe state instead of exiting and entering the unsafe ++ * state. ++ * ++ * Also it can be called in the safe context before doing an expensive ++ * safe operation. It does not make sense to do the operation when ++ * a higher priority context took the lock. ++ * ++ * When this function returns false then the calling context no longer owns ++ * the console and is no longer allowed to go forward. In this case it must ++ * back out immediately and carefully. The buffer content is also no longer ++ * trusted since it no longer belongs to the calling context. ++ */ ++static bool nbcon_context_can_proceed(struct nbcon_context *ctxt, struct nbcon_state *cur) ++{ ++ unsigned int cpu = smp_processor_id(); ++ ++ /* Make sure this context still owns the console. */ ++ if (!nbcon_owner_matches(cur, cpu, ctxt->prio)) ++ return false; ++ ++ /* The console owner can proceed if there is no waiter. */ ++ if (cur->req_prio == NBCON_PRIO_NONE) ++ return true; ++ ++ /* ++ * A console owner within an unsafe region is always allowed to ++ * proceed, even if there are waiters. It can perform a handover ++ * when exiting the unsafe region. Otherwise the waiter will ++ * need to perform an unsafe hostile takeover. ++ */ ++ if (cur->unsafe) ++ return true; ++ ++ /* Waiters always have higher priorities than owners. */ ++ WARN_ON_ONCE(cur->req_prio <= cur->prio); ++ ++ /* ++ * Having a safe point for take over and eventually a few ++ * duplicated characters or a full line is way better than a ++ * hostile takeover. Post processing can take care of the garbage. ++ * Release and hand over. ++ */ ++ nbcon_context_release(ctxt); ++ ++ /* ++ * It is not clear whether the waiter really took over ownership. The ++ * outermost callsite must make the final decision whether console ++ * ownership is needed for it to proceed. If yes, it must reacquire ++ * ownership (possibly hostile) before carefully proceeding. ++ * ++ * The calling context no longer owns the console so go back all the ++ * way instead of trying to implement reacquire heuristics in tons of ++ * places. ++ */ ++ return false; ++} ++ ++#define nbcon_context_enter_unsafe(c) __nbcon_context_update_unsafe(c, true) ++#define nbcon_context_exit_unsafe(c) __nbcon_context_update_unsafe(c, false) ++ ++/** ++ * __nbcon_context_update_unsafe - Update the unsafe bit in @con->nbcon_state ++ * @ctxt: The nbcon context from nbcon_context_try_acquire() ++ * @unsafe: The new value for the unsafe bit ++ * ++ * Return: True if the unsafe state was updated and this context still ++ * owns the console. Otherwise false if ownership was handed ++ * over or taken. ++ * ++ * This function allows console owners to modify the unsafe status of the ++ * console. ++ * ++ * When this function returns false then the calling context no longer owns ++ * the console and is no longer allowed to go forward. In this case it must ++ * back out immediately and carefully. The buffer content is also no longer ++ * trusted since it no longer belongs to the calling context. ++ * ++ * Internal helper to avoid duplicated code. ++ */ ++__maybe_unused ++static bool __nbcon_context_update_unsafe(struct nbcon_context *ctxt, bool unsafe) ++{ ++ struct console *con = ctxt->console; ++ struct nbcon_state cur; ++ struct nbcon_state new; ++ ++ nbcon_state_read(con, &cur); ++ ++ do { ++ /* ++ * The unsafe bit must not be cleared if an ++ * unsafe hostile takeover has occurred. ++ */ ++ if (!unsafe && cur.unsafe_takeover) ++ goto out; ++ ++ if (!nbcon_context_can_proceed(ctxt, &cur)) ++ return false; ++ ++ new.atom = cur.atom; ++ new.unsafe = unsafe; ++ } while (!nbcon_state_try_cmpxchg(con, &cur, &new)); ++ ++ cur.atom = new.atom; ++out: ++ return nbcon_context_can_proceed(ctxt, &cur); ++} ++ ++/** + * nbcon_alloc - Allocate buffers needed by the nbcon console + * @con: Console to allocate buffers for + * diff --git a/debian/patches-rt/0080-printk-nbcon-Add-sequence-handling.patch b/debian/patches-rt/0080-printk-nbcon-Add-sequence-handling.patch new file mode 100644 index 000000000..3988d6124 --- /dev/null +++ b/debian/patches-rt/0080-printk-nbcon-Add-sequence-handling.patch @@ -0,0 +1,311 @@ +From: Thomas Gleixner +Date: Sat, 16 Sep 2023 21:26:05 +0206 +Subject: [PATCH 080/134] printk: nbcon: Add sequence handling +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Add an atomic_long_t field @nbcon_seq to the console struct to +store the sequence number for nbcon consoles. For nbcon consoles +this will be used instead of the non-atomic @seq field. The new +field allows for safe atomic sequence number updates without +requiring any locking. + +On 64bit systems the new field stores the full sequence number. +On 32bit systems the new field stores the lower 32 bits of the +sequence number, which are expanded to 64bit as needed by +folding the values based on the sequence numbers available in +the ringbuffer. + +For 32bit systems, having a 32bit representation in the console +is sufficient. If a console ever gets more than 2^31 records +behind the ringbuffer then this is the least of the problems. + +Co-developed-by: John Ogness +Signed-off-by: John Ogness +Signed-off-by: Thomas Gleixner (Intel) +Signed-off-by: Petr Mladek +Link: https://lore.kernel.org/r/20230916192007.608398-7-john.ogness@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/console.h | 4 + + kernel/printk/internal.h | 7 +++ + kernel/printk/nbcon.c | 101 +++++++++++++++++++++++++++++++++++++++++++++++ + kernel/printk/printk.c | 31 +++++++++++--- + 4 files changed, 136 insertions(+), 7 deletions(-) + +--- a/include/linux/console.h ++++ b/include/linux/console.h +@@ -243,6 +243,7 @@ struct printk_buffers; + * might cause a system freeze when the console + * is used later. + * @pbufs: Pointer to the text buffer for this context ++ * @seq: The sequence number to print for this context + */ + struct nbcon_context { + /* members set by caller */ +@@ -253,6 +254,7 @@ struct nbcon_context { + + /* members set by acquire */ + struct printk_buffers *pbufs; ++ u64 seq; + }; + + /** +@@ -276,6 +278,7 @@ struct nbcon_context { + * @node: hlist node for the console list + * + * @nbcon_state: State for nbcon consoles ++ * @nbcon_seq: Sequence number of the next record for nbcon to print + * @pbufs: Pointer to nbcon private buffer + */ + struct console { +@@ -299,6 +302,7 @@ struct console { + + /* nbcon console specific members */ + atomic_t __private nbcon_state; ++ atomic_long_t __private nbcon_seq; + struct printk_buffers *pbufs; + }; + +--- a/kernel/printk/internal.h ++++ b/kernel/printk/internal.h +@@ -4,6 +4,7 @@ + */ + #include + #include ++#include "printk_ringbuffer.h" + + #if defined(CONFIG_PRINTK) && defined(CONFIG_SYSCTL) + void __init printk_sysctl_init(void); +@@ -42,6 +43,8 @@ enum printk_info_flags { + LOG_CONT = 8, /* text is a fragment of a continuation line */ + }; + ++extern struct printk_ringbuffer *prb; ++ + __printf(4, 0) + int vprintk_store(int facility, int level, + const struct dev_printk_info *dev_info, +@@ -69,6 +72,8 @@ void defer_console_output(void); + u16 printk_parse_prefix(const char *text, int *level, + enum printk_info_flags *flags); + ++u64 nbcon_seq_read(struct console *con); ++void nbcon_seq_force(struct console *con, u64 seq); + bool nbcon_alloc(struct console *con); + void nbcon_init(struct console *con); + void nbcon_free(struct console *con); +@@ -88,6 +93,8 @@ void nbcon_free(struct console *con); + #define printk_safe_exit_irqrestore(flags) local_irq_restore(flags) + + static inline bool printk_percpu_data_ready(void) { return false; } ++static inline u64 nbcon_seq_read(struct console *con) { return 0; } ++static inline void nbcon_seq_force(struct console *con, u64 seq) { } + static inline bool nbcon_alloc(struct console *con) { return false; } + static inline void nbcon_init(struct console *con) { } + static inline void nbcon_free(struct console *con) { } +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -140,6 +140,101 @@ static inline bool nbcon_state_try_cmpxc + return atomic_try_cmpxchg(&ACCESS_PRIVATE(con, nbcon_state), &cur->atom, new->atom); + } + ++#ifdef CONFIG_64BIT ++ ++#define __seq_to_nbcon_seq(seq) (seq) ++#define __nbcon_seq_to_seq(seq) (seq) ++ ++#else /* CONFIG_64BIT */ ++ ++#define __seq_to_nbcon_seq(seq) ((u32)seq) ++ ++static inline u64 __nbcon_seq_to_seq(u32 nbcon_seq) ++{ ++ u64 seq; ++ u64 rb_next_seq; ++ ++ /* ++ * The provided sequence is only the lower 32 bits of the ringbuffer ++ * sequence. It needs to be expanded to 64bit. Get the next sequence ++ * number from the ringbuffer and fold it. ++ * ++ * Having a 32bit representation in the console is sufficient. ++ * If a console ever gets more than 2^31 records behind ++ * the ringbuffer then this is the least of the problems. ++ * ++ * Also the access to the ring buffer is always safe. ++ */ ++ rb_next_seq = prb_next_seq(prb); ++ seq = rb_next_seq - ((u32)rb_next_seq - nbcon_seq); ++ ++ return seq; ++} ++ ++#endif /* CONFIG_64BIT */ ++ ++/** ++ * nbcon_seq_read - Read the current console sequence ++ * @con: Console to read the sequence of ++ * ++ * Return: Sequence number of the next record to print on @con. ++ */ ++u64 nbcon_seq_read(struct console *con) ++{ ++ unsigned long nbcon_seq = atomic_long_read(&ACCESS_PRIVATE(con, nbcon_seq)); ++ ++ return __nbcon_seq_to_seq(nbcon_seq); ++} ++ ++/** ++ * nbcon_seq_force - Force console sequence to a specific value ++ * @con: Console to work on ++ * @seq: Sequence number value to set ++ * ++ * Only to be used during init (before registration) or in extreme situations ++ * (such as panic with CONSOLE_REPLAY_ALL). ++ */ ++void nbcon_seq_force(struct console *con, u64 seq) ++{ ++ /* ++ * If the specified record no longer exists, the oldest available record ++ * is chosen. This is especially important on 32bit systems because only ++ * the lower 32 bits of the sequence number are stored. The upper 32 bits ++ * are derived from the sequence numbers available in the ringbuffer. ++ */ ++ u64 valid_seq = max_t(u64, seq, prb_first_valid_seq(prb)); ++ ++ atomic_long_set(&ACCESS_PRIVATE(con, nbcon_seq), __seq_to_nbcon_seq(valid_seq)); ++ ++ /* Clear con->seq since nbcon consoles use con->nbcon_seq instead. */ ++ con->seq = 0; ++} ++ ++/** ++ * nbcon_seq_try_update - Try to update the console sequence number ++ * @ctxt: Pointer to an acquire context that contains ++ * all information about the acquire mode ++ * @new_seq: The new sequence number to set ++ * ++ * @ctxt->seq is updated to the new value of @con::nbcon_seq (expanded to ++ * the 64bit value). This could be a different value than @new_seq if ++ * nbcon_seq_force() was used or the current context no longer owns the ++ * console. In the later case, it will stop printing anyway. ++ */ ++__maybe_unused ++static void nbcon_seq_try_update(struct nbcon_context *ctxt, u64 new_seq) ++{ ++ unsigned long nbcon_seq = __seq_to_nbcon_seq(ctxt->seq); ++ struct console *con = ctxt->console; ++ ++ if (atomic_long_try_cmpxchg(&ACCESS_PRIVATE(con, nbcon_seq), &nbcon_seq, ++ __seq_to_nbcon_seq(new_seq))) { ++ ctxt->seq = new_seq; ++ } else { ++ ctxt->seq = nbcon_seq_read(con); ++ } ++} ++ + /** + * nbcon_context_try_acquire_direct - Try to acquire directly + * @ctxt: The context of the caller +@@ -510,6 +605,9 @@ static bool nbcon_context_try_acquire(st + else + ctxt->pbufs = con->pbufs; + ++ /* Set the record sequence for this context to print. */ ++ ctxt->seq = nbcon_seq_read(ctxt->console); ++ + return true; + } + +@@ -722,6 +820,8 @@ bool nbcon_alloc(struct console *con) + * + * nbcon_alloc() *must* be called and succeed before this function + * is called. ++ * ++ * This function expects that the legacy @con->seq has been set. + */ + void nbcon_init(struct console *con) + { +@@ -730,6 +830,7 @@ void nbcon_init(struct console *con) + /* nbcon_alloc() must have been called and successful! */ + BUG_ON(!con->pbufs); + ++ nbcon_seq_force(con, con->seq); + nbcon_state_set(con, &state); + } + +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -494,7 +494,7 @@ static u32 log_buf_len = __LOG_BUF_LEN; + + static struct printk_ringbuffer printk_rb_dynamic; + +-static struct printk_ringbuffer *prb = &printk_rb_static; ++struct printk_ringbuffer *prb = &printk_rb_static; + + /* + * We cannot access per-CPU data (e.g. per-CPU flush irq_work) before +@@ -3168,6 +3168,7 @@ void console_flush_on_panic(enum con_flu + + if (mode == CONSOLE_REPLAY_ALL) { + struct console *c; ++ short flags; + int cookie; + u64 seq; + +@@ -3175,11 +3176,17 @@ void console_flush_on_panic(enum con_flu + + cookie = console_srcu_read_lock(); + for_each_console_srcu(c) { +- /* +- * This is an unsynchronized assignment, but the +- * kernel is in "hope and pray" mode anyway. +- */ +- c->seq = seq; ++ flags = console_srcu_read_flags(c); ++ ++ if (flags & CON_NBCON) { ++ nbcon_seq_force(c, seq); ++ } else { ++ /* ++ * This is an unsynchronized assignment. On ++ * panic legacy consoles are only best effort. ++ */ ++ c->seq = seq; ++ } + } + console_srcu_read_unlock(cookie); + } +@@ -3750,6 +3757,7 @@ static bool __pr_flush(struct console *c + struct console *c; + u64 last_diff = 0; + u64 printk_seq; ++ short flags; + int cookie; + u64 diff; + u64 seq; +@@ -3777,6 +3785,9 @@ static bool __pr_flush(struct console *c + for_each_console_srcu(c) { + if (con && con != c) + continue; ++ ++ flags = console_srcu_read_flags(c); ++ + /* + * If consoles are not usable, it cannot be expected + * that they make forward progress, so only increment +@@ -3784,7 +3795,13 @@ static bool __pr_flush(struct console *c + */ + if (!console_is_usable(c)) + continue; +- printk_seq = c->seq; ++ ++ if (flags & CON_NBCON) { ++ printk_seq = nbcon_seq_read(c); ++ } else { ++ printk_seq = c->seq; ++ } ++ + if (printk_seq < seq) + diff += seq - printk_seq; + } diff --git a/debian/patches-rt/0081-printk-nbcon-Add-emit-function-and-callback-function.patch b/debian/patches-rt/0081-printk-nbcon-Add-emit-function-and-callback-function.patch new file mode 100644 index 000000000..ab32a05b1 --- /dev/null +++ b/debian/patches-rt/0081-printk-nbcon-Add-emit-function-and-callback-function.patch @@ -0,0 +1,262 @@ +From: Thomas Gleixner +Date: Sat, 16 Sep 2023 21:26:06 +0206 +Subject: [PATCH 081/134] printk: nbcon: Add emit function and callback + function for atomic printing +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Implement an emit function for nbcon consoles to output printk +messages. It utilizes the lockless printk_get_next_message() and +console_prepend_dropped() functions to retrieve/build the output +message. The emit function includes the required safety points to +check for handover/takeover and calls a new write_atomic callback +of the console driver to output the message. It also includes +proper handling for updating the nbcon console sequence number. + +A new nbcon_write_context struct is introduced. This is provided +to the write_atomic callback and includes only the information +necessary for performing atomic writes. + +Co-developed-by: John Ogness +Signed-off-by: John Ogness +Signed-off-by: Thomas Gleixner (Intel) +Reviewed-by: Petr Mladek +Signed-off-by: Petr Mladek +Link: https://lore.kernel.org/r/20230916192007.608398-8-john.ogness@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/console.h | 21 +++++++++ + kernel/printk/internal.h | 6 ++ + kernel/printk/nbcon.c | 106 ++++++++++++++++++++++++++++++++++++++++++++++- + kernel/printk/printk.c | 9 +-- + 4 files changed, 134 insertions(+), 8 deletions(-) + +--- a/include/linux/console.h ++++ b/include/linux/console.h +@@ -242,6 +242,7 @@ struct printk_buffers; + * be used only with NBCON_PRIO_PANIC @prio. It + * might cause a system freeze when the console + * is used later. ++ * @backlog: Ringbuffer has pending records + * @pbufs: Pointer to the text buffer for this context + * @seq: The sequence number to print for this context + */ +@@ -252,12 +253,29 @@ struct nbcon_context { + enum nbcon_prio prio; + unsigned int allow_unsafe_takeover : 1; + ++ /* members set by emit */ ++ unsigned int backlog : 1; ++ + /* members set by acquire */ + struct printk_buffers *pbufs; + u64 seq; + }; + + /** ++ * struct nbcon_write_context - Context handed to the nbcon write callbacks ++ * @ctxt: The core console context ++ * @outbuf: Pointer to the text buffer for output ++ * @len: Length to write ++ * @unsafe_takeover: If a hostile takeover in an unsafe state has occurred ++ */ ++struct nbcon_write_context { ++ struct nbcon_context __private ctxt; ++ char *outbuf; ++ unsigned int len; ++ bool unsafe_takeover; ++}; ++ ++/** + * struct console - The console descriptor structure + * @name: The name of the console driver + * @write: Write callback to output messages (Optional) +@@ -277,6 +295,7 @@ struct nbcon_context { + * @data: Driver private data + * @node: hlist node for the console list + * ++ * @write_atomic: Write callback for atomic context + * @nbcon_state: State for nbcon consoles + * @nbcon_seq: Sequence number of the next record for nbcon to print + * @pbufs: Pointer to nbcon private buffer +@@ -301,6 +320,8 @@ struct console { + struct hlist_node node; + + /* nbcon console specific members */ ++ bool (*write_atomic)(struct console *con, ++ struct nbcon_write_context *wctxt); + atomic_t __private nbcon_state; + atomic_long_t __private nbcon_seq; + struct printk_buffers *pbufs; +--- a/kernel/printk/internal.h ++++ b/kernel/printk/internal.h +@@ -130,3 +130,9 @@ struct printk_message { + }; + + bool other_cpu_in_panic(void); ++bool printk_get_next_message(struct printk_message *pmsg, u64 seq, ++ bool is_extended, bool may_supress); ++ ++#ifdef CONFIG_PRINTK ++void console_prepend_dropped(struct printk_message *pmsg, unsigned long dropped); ++#endif +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -221,7 +221,6 @@ void nbcon_seq_force(struct console *con + * nbcon_seq_force() was used or the current context no longer owns the + * console. In the later case, it will stop printing anyway. + */ +-__maybe_unused + static void nbcon_seq_try_update(struct nbcon_context *ctxt, u64 new_seq) + { + unsigned long nbcon_seq = __seq_to_nbcon_seq(ctxt->seq); +@@ -755,7 +754,6 @@ static bool nbcon_context_can_proceed(st + * + * Internal helper to avoid duplicated code. + */ +-__maybe_unused + static bool __nbcon_context_update_unsafe(struct nbcon_context *ctxt, bool unsafe) + { + struct console *con = ctxt->console; +@@ -785,6 +783,110 @@ static bool __nbcon_context_update_unsaf + } + + /** ++ * nbcon_emit_next_record - Emit a record in the acquired context ++ * @wctxt: The write context that will be handed to the write function ++ * ++ * Return: True if this context still owns the console. False if ++ * ownership was handed over or taken. ++ * ++ * When this function returns false then the calling context no longer owns ++ * the console and is no longer allowed to go forward. In this case it must ++ * back out immediately and carefully. The buffer content is also no longer ++ * trusted since it no longer belongs to the calling context. If the caller ++ * wants to do more it must reacquire the console first. ++ * ++ * When true is returned, @wctxt->ctxt.backlog indicates whether there are ++ * still records pending in the ringbuffer, ++ */ ++__maybe_unused ++static bool nbcon_emit_next_record(struct nbcon_write_context *wctxt) ++{ ++ struct nbcon_context *ctxt = &ACCESS_PRIVATE(wctxt, ctxt); ++ struct console *con = ctxt->console; ++ bool is_extended = console_srcu_read_flags(con) & CON_EXTENDED; ++ struct printk_message pmsg = { ++ .pbufs = ctxt->pbufs, ++ }; ++ unsigned long con_dropped; ++ struct nbcon_state cur; ++ unsigned long dropped; ++ bool done; ++ ++ /* ++ * The printk buffers are filled within an unsafe section. This ++ * prevents NBCON_PRIO_NORMAL and NBCON_PRIO_EMERGENCY from ++ * clobbering each other. ++ */ ++ ++ if (!nbcon_context_enter_unsafe(ctxt)) ++ return false; ++ ++ ctxt->backlog = printk_get_next_message(&pmsg, ctxt->seq, is_extended, true); ++ if (!ctxt->backlog) ++ return nbcon_context_exit_unsafe(ctxt); ++ ++ /* ++ * @con->dropped is not protected in case of an unsafe hostile ++ * takeover. In that situation the update can be racy so ++ * annotate it accordingly. ++ */ ++ con_dropped = data_race(READ_ONCE(con->dropped)); ++ ++ dropped = con_dropped + pmsg.dropped; ++ if (dropped && !is_extended) ++ console_prepend_dropped(&pmsg, dropped); ++ ++ if (!nbcon_context_exit_unsafe(ctxt)) ++ return false; ++ ++ /* For skipped records just update seq/dropped in @con. */ ++ if (pmsg.outbuf_len == 0) ++ goto update_con; ++ ++ /* Initialize the write context for driver callbacks. */ ++ wctxt->outbuf = &pmsg.pbufs->outbuf[0]; ++ wctxt->len = pmsg.outbuf_len; ++ nbcon_state_read(con, &cur); ++ wctxt->unsafe_takeover = cur.unsafe_takeover; ++ ++ if (con->write_atomic) { ++ done = con->write_atomic(con, wctxt); ++ } else { ++ nbcon_context_release(ctxt); ++ WARN_ON_ONCE(1); ++ done = false; ++ } ++ ++ /* If not done, the emit was aborted. */ ++ if (!done) ++ return false; ++ ++ /* ++ * Since any dropped message was successfully output, reset the ++ * dropped count for the console. ++ */ ++ dropped = 0; ++update_con: ++ /* ++ * The dropped count and the sequence number are updated within an ++ * unsafe section. This limits update races to the panic context and ++ * allows the panic context to win. ++ */ ++ ++ if (!nbcon_context_enter_unsafe(ctxt)) ++ return false; ++ ++ if (dropped != con_dropped) { ++ /* Counterpart to the READ_ONCE() above. */ ++ WRITE_ONCE(con->dropped, dropped); ++ } ++ ++ nbcon_seq_try_update(ctxt, pmsg.seq + 1); ++ ++ return nbcon_context_exit_unsafe(ctxt); ++} ++ ++/** + * nbcon_alloc - Allocate buffers needed by the nbcon console + * @con: Console to allocate buffers for + * +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -698,9 +698,6 @@ static ssize_t msg_print_ext_body(char * + return len; + } + +-static bool printk_get_next_message(struct printk_message *pmsg, u64 seq, +- bool is_extended, bool may_supress); +- + /* /dev/kmsg - userspace message inject/listen interface */ + struct devkmsg_user { + atomic64_t seq; +@@ -2733,7 +2730,7 @@ static void __console_unlock(void) + * If @pmsg->pbufs->outbuf is modified, @pmsg->outbuf_len is updated. + */ + #ifdef CONFIG_PRINTK +-static void console_prepend_dropped(struct printk_message *pmsg, unsigned long dropped) ++void console_prepend_dropped(struct printk_message *pmsg, unsigned long dropped) + { + struct printk_buffers *pbufs = pmsg->pbufs; + const size_t scratchbuf_sz = sizeof(pbufs->scratchbuf); +@@ -2787,8 +2784,8 @@ static void console_prepend_dropped(stru + * of @pmsg are valid. (See the documentation of struct printk_message + * for information about the @pmsg fields.) + */ +-static bool printk_get_next_message(struct printk_message *pmsg, u64 seq, +- bool is_extended, bool may_suppress) ++bool printk_get_next_message(struct printk_message *pmsg, u64 seq, ++ bool is_extended, bool may_suppress) + { + static int panic_console_dropped; + diff --git a/debian/patches-rt/0082-printk-nbcon-Allow-drivers-to-mark-unsafe-regions-an.patch b/debian/patches-rt/0082-printk-nbcon-Allow-drivers-to-mark-unsafe-regions-an.patch new file mode 100644 index 000000000..16a07a839 --- /dev/null +++ b/debian/patches-rt/0082-printk-nbcon-Allow-drivers-to-mark-unsafe-regions-an.patch @@ -0,0 +1,136 @@ +From: Thomas Gleixner +Date: Sat, 16 Sep 2023 21:26:07 +0206 +Subject: [PATCH 082/134] printk: nbcon: Allow drivers to mark unsafe regions + and check state +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +For the write_atomic callback, the console driver may have unsafe +regions that need to be appropriately marked. Provide functions +that accept the nbcon_write_context struct to allow for the driver +to enter and exit unsafe regions. + +Also provide a function for drivers to check if they are still the +owner of the console. + +Co-developed-by: John Ogness +Signed-off-by: John Ogness +Signed-off-by: Thomas Gleixner (Intel) +Reviewed-by: Petr Mladek +Signed-off-by: Petr Mladek +Link: https://lore.kernel.org/r/20230916192007.608398-9-john.ogness@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/console.h | 10 ++++++ + kernel/printk/nbcon.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++++ + 2 files changed, 85 insertions(+) + +--- a/include/linux/console.h ++++ b/include/linux/console.h +@@ -451,6 +451,16 @@ static inline bool console_is_registered + lockdep_assert_console_list_lock_held(); \ + hlist_for_each_entry(con, &console_list, node) + ++#ifdef CONFIG_PRINTK ++extern bool nbcon_can_proceed(struct nbcon_write_context *wctxt); ++extern bool nbcon_enter_unsafe(struct nbcon_write_context *wctxt); ++extern bool nbcon_exit_unsafe(struct nbcon_write_context *wctxt); ++#else ++static inline bool nbcon_can_proceed(struct nbcon_write_context *wctxt) { return false; } ++static inline bool nbcon_enter_unsafe(struct nbcon_write_context *wctxt) { return false; } ++static inline bool nbcon_exit_unsafe(struct nbcon_write_context *wctxt) { return false; } ++#endif ++ + extern int console_set_on_cmdline; + extern struct console *early_console; + +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -732,6 +732,41 @@ static bool nbcon_context_can_proceed(st + return false; + } + ++/** ++ * nbcon_can_proceed - Check whether ownership can proceed ++ * @wctxt: The write context that was handed to the write function ++ * ++ * Return: True if this context still owns the console. False if ++ * ownership was handed over or taken. ++ * ++ * It is used in nbcon_enter_unsafe() to make sure that it still owns the ++ * lock. Also it is used in nbcon_exit_unsafe() to eventually free the lock ++ * for a higher priority context which asked for the friendly handover. ++ * ++ * It can be called inside an unsafe section when the console is just ++ * temporary in safe state instead of exiting and entering the unsafe state. ++ * ++ * Also it can be called in the safe context before doing an expensive safe ++ * operation. It does not make sense to do the operation when a higher ++ * priority context took the lock. ++ * ++ * When this function returns false then the calling context no longer owns ++ * the console and is no longer allowed to go forward. In this case it must ++ * back out immediately and carefully. The buffer content is also no longer ++ * trusted since it no longer belongs to the calling context. ++ */ ++bool nbcon_can_proceed(struct nbcon_write_context *wctxt) ++{ ++ struct nbcon_context *ctxt = &ACCESS_PRIVATE(wctxt, ctxt); ++ struct console *con = ctxt->console; ++ struct nbcon_state cur; ++ ++ nbcon_state_read(con, &cur); ++ ++ return nbcon_context_can_proceed(ctxt, &cur); ++} ++EXPORT_SYMBOL_GPL(nbcon_can_proceed); ++ + #define nbcon_context_enter_unsafe(c) __nbcon_context_update_unsafe(c, true) + #define nbcon_context_exit_unsafe(c) __nbcon_context_update_unsafe(c, false) + +@@ -783,6 +818,46 @@ static bool __nbcon_context_update_unsaf + } + + /** ++ * nbcon_enter_unsafe - Enter an unsafe region in the driver ++ * @wctxt: The write context that was handed to the write function ++ * ++ * Return: True if this context still owns the console. False if ++ * ownership was handed over or taken. ++ * ++ * When this function returns false then the calling context no longer owns ++ * the console and is no longer allowed to go forward. In this case it must ++ * back out immediately and carefully. The buffer content is also no longer ++ * trusted since it no longer belongs to the calling context. ++ */ ++bool nbcon_enter_unsafe(struct nbcon_write_context *wctxt) ++{ ++ struct nbcon_context *ctxt = &ACCESS_PRIVATE(wctxt, ctxt); ++ ++ return nbcon_context_enter_unsafe(ctxt); ++} ++EXPORT_SYMBOL_GPL(nbcon_enter_unsafe); ++ ++/** ++ * nbcon_exit_unsafe - Exit an unsafe region in the driver ++ * @wctxt: The write context that was handed to the write function ++ * ++ * Return: True if this context still owns the console. False if ++ * ownership was handed over or taken. ++ * ++ * When this function returns false then the calling context no longer owns ++ * the console and is no longer allowed to go forward. In this case it must ++ * back out immediately and carefully. The buffer content is also no longer ++ * trusted since it no longer belongs to the calling context. ++ */ ++bool nbcon_exit_unsafe(struct nbcon_write_context *wctxt) ++{ ++ struct nbcon_context *ctxt = &ACCESS_PRIVATE(wctxt, ctxt); ++ ++ return nbcon_context_exit_unsafe(ctxt); ++} ++EXPORT_SYMBOL_GPL(nbcon_exit_unsafe); ++ ++/** + * nbcon_emit_next_record - Emit a record in the acquired context + * @wctxt: The write context that will be handed to the write function + * diff --git a/debian/patches-rt/0083-printk-fix-illegal-pbufs-access-for-CONFIG_PRINTK.patch b/debian/patches-rt/0083-printk-fix-illegal-pbufs-access-for-CONFIG_PRINTK.patch new file mode 100644 index 000000000..80de1c716 --- /dev/null +++ b/debian/patches-rt/0083-printk-fix-illegal-pbufs-access-for-CONFIG_PRINTK.patch @@ -0,0 +1,134 @@ +From: John Ogness +Date: Wed, 20 Sep 2023 17:58:38 +0206 +Subject: [PATCH 083/134] printk: fix illegal pbufs access for !CONFIG_PRINTK +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When CONFIG_PRINTK is not set, PRINTK_MESSAGE_MAX is 0. This +leads to a zero-sized array @outbuf in @printk_shared_pbufs. In +console_flush_all() a pointer to the first element of the array +is assigned with: + + char *outbuf = &printk_shared_pbufs.outbuf[0]; + +For !CONFIG_PRINTK this leads to a compiler warning: + + warning: array subscript 0 is outside array bounds of + 'char[0]' [-Warray-bounds] + +This is not really dangerous because printk_get_next_message() +always returns false for !CONFIG_PRINTK, which leads to @outbuf +never being used. However, it makes no sense to even compile +these functions for !CONFIG_PRINTK. + +Extend the existing '#ifdef CONFIG_PRINTK' block to contain +the formatting and emitting functions since these have no +purpose in !CONFIG_PRINTK. This also allows removing several +more !CONFIG_PRINTK dummies as well as moving +@suppress_panic_printk into a CONFIG_PRINTK block. + +Reported-by: kernel test robot +Closes: https://lore.kernel.org/oe-kbuild-all/202309201724.M9BMAQIh-lkp@intel.com/ +Signed-off-by: John Ogness +Reviewed-by: Sergey Senozhatsky +Signed-off-by: Petr Mladek +Link: https://lore.kernel.org/r/20230920155238.670439-1-john.ogness@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/printk.c | 44 ++++++++++++++++++-------------------------- + 1 file changed, 18 insertions(+), 26 deletions(-) + +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -102,12 +102,6 @@ DEFINE_STATIC_SRCU(console_srcu); + */ + int __read_mostly suppress_printk; + +-/* +- * During panic, heavy printk by other CPUs can delay the +- * panic and risk deadlock on console resources. +- */ +-static int __read_mostly suppress_panic_printk; +- + #ifdef CONFIG_LOCKDEP + static struct lockdep_map console_lock_dep_map = { + .name = "console_lock" +@@ -445,6 +439,12 @@ static int console_msg_format = MSG_FORM + static DEFINE_MUTEX(syslog_lock); + + #ifdef CONFIG_PRINTK ++/* ++ * During panic, heavy printk by other CPUs can delay the ++ * panic and risk deadlock on console resources. ++ */ ++static int __read_mostly suppress_panic_printk; ++ + DECLARE_WAIT_QUEUE_HEAD(log_wait); + /* All 3 protected by @syslog_lock. */ + /* the next printk record to read by syslog(READ) or /proc/kmsg */ +@@ -2346,22 +2346,6 @@ static bool __pr_flush(struct console *c + + static u64 syslog_seq; + +-static size_t record_print_text(const struct printk_record *r, +- bool syslog, bool time) +-{ +- return 0; +-} +-static ssize_t info_print_ext_header(char *buf, size_t size, +- struct printk_info *info) +-{ +- return 0; +-} +-static ssize_t msg_print_ext_body(char *buf, size_t size, +- char *text, size_t text_len, +- struct dev_printk_info *dev_info) { return 0; } +-static void console_lock_spinning_enable(void) { } +-static int console_lock_spinning_disable_and_check(int cookie) { return 0; } +-static bool suppress_message_printing(int level) { return false; } + static bool pr_flush(int timeout_ms, bool reset_on_progress) { return true; } + static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progress) { return true; } + +@@ -2715,6 +2699,8 @@ static void __console_unlock(void) + up_console_sem(); + } + ++#ifdef CONFIG_PRINTK ++ + /* + * Prepend the message in @pmsg->pbufs->outbuf with a "dropped message". This + * is achieved by shifting the existing message over and inserting the dropped +@@ -2729,7 +2715,6 @@ static void __console_unlock(void) + * + * If @pmsg->pbufs->outbuf is modified, @pmsg->outbuf_len is updated. + */ +-#ifdef CONFIG_PRINTK + void console_prepend_dropped(struct printk_message *pmsg, unsigned long dropped) + { + struct printk_buffers *pbufs = pmsg->pbufs; +@@ -2761,9 +2746,6 @@ void console_prepend_dropped(struct prin + memcpy(outbuf, scratchbuf, len); + pmsg->outbuf_len += len; + } +-#else +-#define console_prepend_dropped(pmsg, dropped) +-#endif /* CONFIG_PRINTK */ + + /* + * Read and format the specified record (or a later record if the specified +@@ -2921,6 +2903,16 @@ static bool console_emit_next_record(str + return true; + } + ++#else ++ ++static bool console_emit_next_record(struct console *con, bool *handover, int cookie) ++{ ++ *handover = false; ++ return false; ++} ++ ++#endif /* CONFIG_PRINTK */ ++ + /* + * Print out all remaining records to all consoles. + * diff --git a/debian/patches-rt/0084-printk-Reduce-pr_flush-pooling-time.patch b/debian/patches-rt/0084-printk-Reduce-pr_flush-pooling-time.patch new file mode 100644 index 000000000..09d1d343f --- /dev/null +++ b/debian/patches-rt/0084-printk-Reduce-pr_flush-pooling-time.patch @@ -0,0 +1,102 @@ +From: Petr Mladek +Date: Fri, 6 Oct 2023 10:21:51 +0200 +Subject: [PATCH 084/134] printk: Reduce pr_flush() pooling time +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +pr_flush() does not guarantee that all messages would really get flushed +to the console. The best it could do is to wait with a given timeout.[*] + +The current interval 100ms for checking the progress might seem too +long in some situations. For example, such delays are not appreciated +during suspend and resume especially when the consoles have been flushed +"long" time before the check. + +On the other hand, the sleeping wait might be useful in other situations. +Especially, it would allow flushing the messages using printk kthreads +on the same CPU[*]. + +Use msleep(1) as a compromise. + +Also measure the time using jiffies. msleep() does not guarantee +precise wakeup after the given delay. It might be much longer, +especially for times < 20s. See Documentation/timers/timers-howto.rst +for more details. + +Note that msecs_to_jiffies() already translates a negative value into +an infinite timeout. + +[*] console_unlock() does not guarantee flushing the consoles since + the commit dbdda842fe96f893 ("printk: Add console owner and waiter + logic to load balance console writes"). + + It would be possible to guarantee it another way. For example, + the spinning might be enabled only when the console_lock has been + taken via console_trylock(). + + But the load balancing is helpful. And more importantly, the flush + with a timeout has been added as a preparation step for introducing + printk kthreads. + +Signed-off-by: Petr Mladek +Reviewed-by: John Ogness +Link: https://lore.kernel.org/r/20231006082151.6969-3-pmladek@suse.com +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/printk.c | 26 +++++++++++++------------- + 1 file changed, 13 insertions(+), 13 deletions(-) + +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -3742,7 +3742,8 @@ late_initcall(printk_late_init); + /* If @con is specified, only wait for that console. Otherwise wait for all. */ + static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progress) + { +- int remaining = timeout_ms; ++ unsigned long timeout_jiffies = msecs_to_jiffies(timeout_ms); ++ unsigned long remaining_jiffies = timeout_jiffies; + struct console *c; + u64 last_diff = 0; + u64 printk_seq; +@@ -3760,6 +3761,9 @@ static bool __pr_flush(struct console *c + console_unlock(); + + for (;;) { ++ unsigned long begin_jiffies; ++ unsigned long slept_jiffies; ++ + diff = 0; + + /* +@@ -3797,24 +3801,20 @@ static bool __pr_flush(struct console *c + console_srcu_read_unlock(cookie); + + if (diff != last_diff && reset_on_progress) +- remaining = timeout_ms; ++ remaining_jiffies = timeout_jiffies; + + console_unlock(); + + /* Note: @diff is 0 if there are no usable consoles. */ +- if (diff == 0 || remaining == 0) ++ if (diff == 0 || remaining_jiffies == 0) + break; + +- if (remaining < 0) { +- /* no timeout limit */ +- msleep(100); +- } else if (remaining < 100) { +- msleep(remaining); +- remaining = 0; +- } else { +- msleep(100); +- remaining -= 100; +- } ++ /* msleep(1) might sleep much longer. Check time by jiffies. */ ++ begin_jiffies = jiffies; ++ msleep(1); ++ slept_jiffies = jiffies - begin_jiffies; ++ ++ remaining_jiffies -= min(slept_jiffies, remaining_jiffies); + + last_diff = diff; + } diff --git a/debian/patches-rt/0085-printk-nbcon-Relocate-32bit-seq-macros.patch b/debian/patches-rt/0085-printk-nbcon-Relocate-32bit-seq-macros.patch new file mode 100644 index 000000000..6d1cf3686 --- /dev/null +++ b/debian/patches-rt/0085-printk-nbcon-Relocate-32bit-seq-macros.patch @@ -0,0 +1,141 @@ +From: John Ogness +Date: Wed, 6 Dec 2023 12:01:56 +0000 +Subject: [PATCH 085/134] printk: nbcon: Relocate 32bit seq macros +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +The macros __seq_to_nbcon_seq() and __nbcon_seq_to_seq() are +used to provide support for atomic handling of sequence numbers +on 32bit systems. Until now this was only used by nbcon.c, +which is why they were located in nbcon.c and include nbcon in +the name. + +In a follow-up commit this functionality is also needed by +printk_ringbuffer. Rather than duplicating the functionality, +relocate the macros to printk_ringbuffer.h. + +Also, since the macros will be no longer nbcon-specific, rename +them to __u64seq_to_ulseq() and __ulseq_to_u64seq(). + +This does not result in any functional change. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/nbcon.c | 41 +++----------------------------------- + kernel/printk/printk_ringbuffer.h | 33 ++++++++++++++++++++++++++++++ + 2 files changed, 37 insertions(+), 37 deletions(-) + +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -140,39 +140,6 @@ static inline bool nbcon_state_try_cmpxc + return atomic_try_cmpxchg(&ACCESS_PRIVATE(con, nbcon_state), &cur->atom, new->atom); + } + +-#ifdef CONFIG_64BIT +- +-#define __seq_to_nbcon_seq(seq) (seq) +-#define __nbcon_seq_to_seq(seq) (seq) +- +-#else /* CONFIG_64BIT */ +- +-#define __seq_to_nbcon_seq(seq) ((u32)seq) +- +-static inline u64 __nbcon_seq_to_seq(u32 nbcon_seq) +-{ +- u64 seq; +- u64 rb_next_seq; +- +- /* +- * The provided sequence is only the lower 32 bits of the ringbuffer +- * sequence. It needs to be expanded to 64bit. Get the next sequence +- * number from the ringbuffer and fold it. +- * +- * Having a 32bit representation in the console is sufficient. +- * If a console ever gets more than 2^31 records behind +- * the ringbuffer then this is the least of the problems. +- * +- * Also the access to the ring buffer is always safe. +- */ +- rb_next_seq = prb_next_seq(prb); +- seq = rb_next_seq - ((u32)rb_next_seq - nbcon_seq); +- +- return seq; +-} +- +-#endif /* CONFIG_64BIT */ +- + /** + * nbcon_seq_read - Read the current console sequence + * @con: Console to read the sequence of +@@ -183,7 +150,7 @@ u64 nbcon_seq_read(struct console *con) + { + unsigned long nbcon_seq = atomic_long_read(&ACCESS_PRIVATE(con, nbcon_seq)); + +- return __nbcon_seq_to_seq(nbcon_seq); ++ return __ulseq_to_u64seq(prb, nbcon_seq); + } + + /** +@@ -204,7 +171,7 @@ void nbcon_seq_force(struct console *con + */ + u64 valid_seq = max_t(u64, seq, prb_first_valid_seq(prb)); + +- atomic_long_set(&ACCESS_PRIVATE(con, nbcon_seq), __seq_to_nbcon_seq(valid_seq)); ++ atomic_long_set(&ACCESS_PRIVATE(con, nbcon_seq), __u64seq_to_ulseq(valid_seq)); + + /* Clear con->seq since nbcon consoles use con->nbcon_seq instead. */ + con->seq = 0; +@@ -223,11 +190,11 @@ void nbcon_seq_force(struct console *con + */ + static void nbcon_seq_try_update(struct nbcon_context *ctxt, u64 new_seq) + { +- unsigned long nbcon_seq = __seq_to_nbcon_seq(ctxt->seq); ++ unsigned long nbcon_seq = __u64seq_to_ulseq(ctxt->seq); + struct console *con = ctxt->console; + + if (atomic_long_try_cmpxchg(&ACCESS_PRIVATE(con, nbcon_seq), &nbcon_seq, +- __seq_to_nbcon_seq(new_seq))) { ++ __u64seq_to_ulseq(new_seq))) { + ctxt->seq = new_seq; + } else { + ctxt->seq = nbcon_seq_read(con); +--- a/kernel/printk/printk_ringbuffer.h ++++ b/kernel/printk/printk_ringbuffer.h +@@ -381,4 +381,37 @@ bool prb_read_valid_info(struct printk_r + u64 prb_first_valid_seq(struct printk_ringbuffer *rb); + u64 prb_next_seq(struct printk_ringbuffer *rb); + ++#ifdef CONFIG_64BIT ++ ++#define __u64seq_to_ulseq(u64seq) (u64seq) ++#define __ulseq_to_u64seq(rb, ulseq) (ulseq) ++ ++#else /* CONFIG_64BIT */ ++ ++#define __u64seq_to_ulseq(u64seq) ((u32)u64seq) ++ ++static inline u64 __ulseq_to_u64seq(struct printk_ringbuffer *rb, u32 ulseq) ++{ ++ u64 seq; ++ u64 rb_next_seq; ++ ++ /* ++ * The provided sequence is only the lower 32 bits of the ringbuffer ++ * sequence. It needs to be expanded to 64bit. Get the next sequence ++ * number from the ringbuffer and fold it. ++ * ++ * Having a 32bit representation in the console is sufficient. ++ * If a console ever gets more than 2^31 records behind ++ * the ringbuffer then this is the least of the problems. ++ * ++ * Also the access to the ring buffer is always safe. ++ */ ++ rb_next_seq = prb_next_seq(rb); ++ seq = rb_next_seq - ((u32)rb_next_seq - ulseq); ++ ++ return seq; ++} ++ ++#endif /* CONFIG_64BIT */ ++ + #endif /* _KERNEL_PRINTK_RINGBUFFER_H */ diff --git a/debian/patches-rt/0086-printk-Adjust-mapping-for-32bit-seq-macros.patch b/debian/patches-rt/0086-printk-Adjust-mapping-for-32bit-seq-macros.patch new file mode 100644 index 000000000..d6ff341f4 --- /dev/null +++ b/debian/patches-rt/0086-printk-Adjust-mapping-for-32bit-seq-macros.patch @@ -0,0 +1,71 @@ +From: Sebastian Andrzej Siewior +Date: Thu, 7 Dec 2023 14:15:15 +0000 +Subject: [PATCH 086/134] printk: Adjust mapping for 32bit seq macros +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Note: This change only applies to 32bit architectures. On 64bit + architectures the macros are NOPs. + +__ulseq_to_u64seq() computes the upper 32 bits of the passed +argument value (@ulseq). The upper bits are derived from a base +value (@rb_next_seq) in a way that assumes @ulseq represents a +64bit number that is less than or equal to @rb_next_seq. + +Until now this mapping has been correct for all call sites. However, +in a follow-up commit, values of @ulseq will be passed in that are +higher than the base value. This requires a change to how the 32bit +value is mapped to a 64bit sequence number. + +Rather than mapping @ulseq such that the base value is the end of a +32bit block, map @ulseq such that the base value is in the middle of +a 32bit block. This allows supporting 31 bits before and after the +base value, which is deemed acceptable for the console sequence +number during runtime. + +Here is an example to illustrate the previous and new mappings. + +For a base value (@rb_next_seq) of 2 2000 0000... + +Before this change the range of possible return values was: + +1 2000 0001 to 2 2000 0000 + +__ulseq_to_u64seq(1fff ffff) => 2 1fff ffff +__ulseq_to_u64seq(2000 0000) => 2 2000 0000 +__ulseq_to_u64seq(2000 0001) => 1 2000 0001 +__ulseq_to_u64seq(9fff ffff) => 1 9fff ffff +__ulseq_to_u64seq(a000 0000) => 1 a000 0000 +__ulseq_to_u64seq(a000 0001) => 1 a000 0001 + +After this change the range of possible return values are: +1 a000 0001 to 2 a000 0000 + +__ulseq_to_u64seq(1fff ffff) => 2 1fff ffff +__ulseq_to_u64seq(2000 0000) => 2 2000 0000 +__ulseq_to_u64seq(2000 0001) => 2 2000 0001 +__ulseq_to_u64seq(9fff ffff) => 2 9fff ffff +__ulseq_to_u64seq(a000 0000) => 2 a000 0000 +__ulseq_to_u64seq(a000 0001) => 1 a000 0001 + +[ john.ogness: Rewrite commit message. ] + +Reported-by: Francesco Dolcini +Reported-by: kernel test robot +Signed-off-by: Sebastian Andrzej Siewior +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/printk_ringbuffer.h | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +--- a/kernel/printk/printk_ringbuffer.h ++++ b/kernel/printk/printk_ringbuffer.h +@@ -407,7 +407,7 @@ static inline u64 __ulseq_to_u64seq(stru + * Also the access to the ring buffer is always safe. + */ + rb_next_seq = prb_next_seq(rb); +- seq = rb_next_seq - ((u32)rb_next_seq - ulseq); ++ seq = rb_next_seq - (s32)((u32)rb_next_seq - ulseq); + + return seq; + } diff --git a/debian/patches-rt/0087-printk-Use-prb_first_seq-as-base-for-32bit-seq-macro.patch b/debian/patches-rt/0087-printk-Use-prb_first_seq-as-base-for-32bit-seq-macro.patch new file mode 100644 index 000000000..2ed6d52b5 --- /dev/null +++ b/debian/patches-rt/0087-printk-Use-prb_first_seq-as-base-for-32bit-seq-macro.patch @@ -0,0 +1,71 @@ +From: John Ogness +Date: Wed, 22 Nov 2023 16:13:37 +0000 +Subject: [PATCH 087/134] printk: Use prb_first_seq() as base for 32bit seq + macros +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Note: This change only applies to 32bit architectures. On 64bit + architectures the macros are NOPs. + +Currently prb_next_seq() is used as the base for the 32bit seq +macros __u64seq_to_ulseq() and __ulseq_to_u64seq(). However, in +a follow-up commit, prb_next_seq() will need to make use of the +32bit seq macros. + +Use prb_first_seq() as the base for the 32bit seq macros instead +because it is guaranteed to return 64bit sequence numbers without +relying on any 32bit seq macros. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/printk_ringbuffer.c | 2 +- + kernel/printk/printk_ringbuffer.h | 8 ++++---- + 2 files changed, 5 insertions(+), 5 deletions(-) + +--- a/kernel/printk/printk_ringbuffer.c ++++ b/kernel/printk/printk_ringbuffer.c +@@ -1832,7 +1832,7 @@ static int prb_read(struct printk_ringbu + } + + /* Get the sequence number of the tail descriptor. */ +-static u64 prb_first_seq(struct printk_ringbuffer *rb) ++u64 prb_first_seq(struct printk_ringbuffer *rb) + { + struct prb_desc_ring *desc_ring = &rb->desc_ring; + enum desc_state d_state; +--- a/kernel/printk/printk_ringbuffer.h ++++ b/kernel/printk/printk_ringbuffer.h +@@ -378,6 +378,7 @@ bool prb_read_valid(struct printk_ringbu + bool prb_read_valid_info(struct printk_ringbuffer *rb, u64 seq, + struct printk_info *info, unsigned int *line_count); + ++u64 prb_first_seq(struct printk_ringbuffer *rb); + u64 prb_first_valid_seq(struct printk_ringbuffer *rb); + u64 prb_next_seq(struct printk_ringbuffer *rb); + +@@ -392,12 +393,12 @@ u64 prb_next_seq(struct printk_ringbuffe + + static inline u64 __ulseq_to_u64seq(struct printk_ringbuffer *rb, u32 ulseq) + { ++ u64 rb_first_seq = prb_first_seq(rb); + u64 seq; +- u64 rb_next_seq; + + /* + * The provided sequence is only the lower 32 bits of the ringbuffer +- * sequence. It needs to be expanded to 64bit. Get the next sequence ++ * sequence. It needs to be expanded to 64bit. Get the first sequence + * number from the ringbuffer and fold it. + * + * Having a 32bit representation in the console is sufficient. +@@ -406,8 +407,7 @@ static inline u64 __ulseq_to_u64seq(stru + * + * Also the access to the ring buffer is always safe. + */ +- rb_next_seq = prb_next_seq(rb); +- seq = rb_next_seq - (s32)((u32)rb_next_seq - ulseq); ++ seq = rb_first_seq - (s32)((u32)rb_first_seq - ulseq); + + return seq; + } diff --git a/debian/patches-rt/0088-printk-ringbuffer-Do-not-skip-non-finalized-records-.patch b/debian/patches-rt/0088-printk-ringbuffer-Do-not-skip-non-finalized-records-.patch new file mode 100644 index 000000000..917f777f1 --- /dev/null +++ b/debian/patches-rt/0088-printk-ringbuffer-Do-not-skip-non-finalized-records-.patch @@ -0,0 +1,304 @@ +From: John Ogness +Date: Thu, 19 Oct 2023 10:32:05 +0000 +Subject: [PATCH 088/134] printk: ringbuffer: Do not skip non-finalized records + with prb_next_seq() +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Commit f244b4dc53e5 ("printk: ringbuffer: Improve +prb_next_seq() performance") introduced an optimization for +prb_next_seq() by using best-effort to track recently finalized +records. However, the order of finalization does not +necessarily match the order of the records. The optimization +changed prb_next_seq() to return inconsistent results, possibly +yielding sequence numbers that are not available to readers +because they are preceded by non-finalized records or they are +not yet visible to the reader CPU. + +Rather than simply best-effort tracking recently finalized +records, force the committing writer to read records and +increment the last "contiguous block" of finalized records. In +order to do this, the sequence number instead of ID must be +stored because ID's cannot be directly compared. + +A new memory barrier pair is introduced to guarantee that a +reader can always read the records up until the sequence number +returned by prb_next_seq() (unless the records have since +been overwritten in the ringbuffer). + +This restores the original functionality of prb_next_seq() +while also keeping the optimization. + +For 32bit systems, only the lower 32 bits of the sequence +number are stored. When reading the value, it is expanded to +the full 64bit sequence number using the 32bit seq macros, +which fold in the value returned by prb_first_seq(). + +Fixes: f244b4dc53e5 ("printk: ringbuffer: Improve prb_next_seq() performance") +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/printk_ringbuffer.c | 164 ++++++++++++++++++++++++++++---------- + kernel/printk/printk_ringbuffer.h | 4 + 2 files changed, 127 insertions(+), 41 deletions(-) + +--- a/kernel/printk/printk_ringbuffer.c ++++ b/kernel/printk/printk_ringbuffer.c +@@ -6,6 +6,7 @@ + #include + #include + #include "printk_ringbuffer.h" ++#include "internal.h" + + /** + * DOC: printk_ringbuffer overview +@@ -303,6 +304,9 @@ + * + * desc_push_tail:B / desc_reserve:D + * set descriptor reusable (state), then push descriptor tail (id) ++ * ++ * desc_update_last_finalized:A / desc_last_finalized_seq:A ++ * store finalized record, then set new highest finalized sequence number + */ + + #define DATA_SIZE(data_ring) _DATA_SIZE((data_ring)->size_bits) +@@ -1442,19 +1446,117 @@ bool prb_reserve_in_last(struct prb_rese + } + + /* ++ * @last_finalized_seq value guarantees that all records up to and including ++ * this sequence number are finalized and can be read. The only exception are ++ * too old records which have already been overwritten. ++ * ++ * It is also guaranteed that @last_finalized_seq only increases. ++ * ++ * Be aware that finalized records following non-finalized records are not ++ * reported because they are not yet available to the reader. For example, ++ * a new record stored via printk() will not be available to a printer if ++ * it follows a record that has not been finalized yet. However, once that ++ * non-finalized record becomes finalized, @last_finalized_seq will be ++ * appropriately updated and the full set of finalized records will be ++ * available to the printer. And since each printk() caller will either ++ * directly print or trigger deferred printing of all available unprinted ++ * records, all printk() messages will get printed. ++ */ ++static u64 desc_last_finalized_seq(struct printk_ringbuffer *rb) ++{ ++ struct prb_desc_ring *desc_ring = &rb->desc_ring; ++ unsigned long ulseq; ++ ++ /* ++ * Guarantee the sequence number is loaded before loading the ++ * associated record in order to guarantee that the record can be ++ * seen by this CPU. This pairs with desc_update_last_finalized:A. ++ */ ++ ulseq = atomic_long_read_acquire(&desc_ring->last_finalized_seq ++ ); /* LMM(desc_last_finalized_seq:A) */ ++ ++ return __ulseq_to_u64seq(rb, ulseq); ++} ++ ++static bool _prb_read_valid(struct printk_ringbuffer *rb, u64 *seq, ++ struct printk_record *r, unsigned int *line_count); ++ ++/* ++ * Check if there are records directly following @last_finalized_seq that are ++ * finalized. If so, update @last_finalized_seq to the latest of these ++ * records. It is not allowed to skip over records that are not yet finalized. ++ */ ++static void desc_update_last_finalized(struct printk_ringbuffer *rb) ++{ ++ struct prb_desc_ring *desc_ring = &rb->desc_ring; ++ u64 old_seq = desc_last_finalized_seq(rb); ++ unsigned long oldval; ++ unsigned long newval; ++ u64 finalized_seq; ++ u64 try_seq; ++ ++try_again: ++ finalized_seq = old_seq; ++ try_seq = finalized_seq + 1; ++ ++ /* Try to find later finalized records. */ ++ while (_prb_read_valid(rb, &try_seq, NULL, NULL)) { ++ finalized_seq = try_seq; ++ try_seq++; ++ } ++ ++ /* No update needed if no later finalized record was found. */ ++ if (finalized_seq == old_seq) ++ return; ++ ++ oldval = __u64seq_to_ulseq(old_seq); ++ newval = __u64seq_to_ulseq(finalized_seq); ++ ++ /* ++ * Set the sequence number of a later finalized record that has been ++ * seen. ++ * ++ * Guarantee the record data is visible to other CPUs before storing ++ * its sequence number. This pairs with desc_last_finalized_seq:A. ++ * ++ * Memory barrier involvement: ++ * ++ * If desc_last_finalized_seq:A reads from ++ * desc_update_last_finalized:A, then desc_read:A reads from ++ * _prb_commit:B. ++ * ++ * Relies on: ++ * ++ * RELEASE from _prb_commit:B to desc_update_last_finalized:A ++ * matching ++ * ACQUIRE from desc_last_finalized_seq:A to desc_read:A ++ * ++ * Note: _prb_commit:B and desc_update_last_finalized:A can be ++ * different CPUs. However, the desc_update_last_finalized:A ++ * CPU (which performs the release) must have previously seen ++ * _prb_commit:B. ++ */ ++ if (!atomic_long_try_cmpxchg_release(&desc_ring->last_finalized_seq, ++ &oldval, newval)) { /* LMM(desc_update_last_finalized:A) */ ++ old_seq = __ulseq_to_u64seq(rb, oldval); ++ goto try_again; ++ } ++} ++ ++/* + * Attempt to finalize a specified descriptor. If this fails, the descriptor + * is either already final or it will finalize itself when the writer commits. + */ +-static void desc_make_final(struct prb_desc_ring *desc_ring, unsigned long id) ++static void desc_make_final(struct printk_ringbuffer *rb, unsigned long id) + { ++ struct prb_desc_ring *desc_ring = &rb->desc_ring; + unsigned long prev_state_val = DESC_SV(id, desc_committed); + struct prb_desc *d = to_desc(desc_ring, id); + +- atomic_long_cmpxchg_relaxed(&d->state_var, prev_state_val, +- DESC_SV(id, desc_finalized)); /* LMM(desc_make_final:A) */ +- +- /* Best effort to remember the last finalized @id. */ +- atomic_long_set(&desc_ring->last_finalized_id, id); ++ if (atomic_long_try_cmpxchg_relaxed(&d->state_var, &prev_state_val, ++ DESC_SV(id, desc_finalized))) { /* LMM(desc_make_final:A) */ ++ desc_update_last_finalized(rb); ++ } + } + + /** +@@ -1550,7 +1652,7 @@ bool prb_reserve(struct prb_reserved_ent + * readers. (For seq==0 there is no previous descriptor.) + */ + if (info->seq > 0) +- desc_make_final(desc_ring, DESC_ID(id - 1)); ++ desc_make_final(rb, DESC_ID(id - 1)); + + r->text_buf = data_alloc(rb, r->text_buf_size, &d->text_blk_lpos, id); + /* If text data allocation fails, a data-less record is committed. */ +@@ -1643,7 +1745,7 @@ void prb_commit(struct prb_reserved_entr + */ + head_id = atomic_long_read(&desc_ring->head_id); /* LMM(prb_commit:A) */ + if (head_id != e->id) +- desc_make_final(desc_ring, e->id); ++ desc_make_final(e->rb, e->id); + } + + /** +@@ -1663,12 +1765,9 @@ void prb_commit(struct prb_reserved_entr + */ + void prb_final_commit(struct prb_reserved_entry *e) + { +- struct prb_desc_ring *desc_ring = &e->rb->desc_ring; +- + _prb_commit(e, desc_finalized); + +- /* Best effort to remember the last finalized @id. */ +- atomic_long_set(&desc_ring->last_finalized_id, e->id); ++ desc_update_last_finalized(e->rb); + } + + /* +@@ -2008,7 +2107,9 @@ u64 prb_first_valid_seq(struct printk_ri + * newest sequence number available to readers will be. + * + * This provides readers a sequence number to jump to if all currently +- * available records should be skipped. ++ * available records should be skipped. It is guaranteed that all records ++ * previous to the returned value have been finalized and are (or were) ++ * available to the reader. + * + * Context: Any context. + * Return: The sequence number of the next newest (not yet available) record +@@ -2016,34 +2117,19 @@ u64 prb_first_valid_seq(struct printk_ri + */ + u64 prb_next_seq(struct printk_ringbuffer *rb) + { +- struct prb_desc_ring *desc_ring = &rb->desc_ring; +- enum desc_state d_state; +- unsigned long id; + u64 seq; + +- /* Check if the cached @id still points to a valid @seq. */ +- id = atomic_long_read(&desc_ring->last_finalized_id); +- d_state = desc_read(desc_ring, id, NULL, &seq, NULL); ++ seq = desc_last_finalized_seq(rb); + +- if (d_state == desc_finalized || d_state == desc_reusable) { +- /* +- * Begin searching after the last finalized record. +- * +- * On 0, the search must begin at 0 because of hack#2 +- * of the bootstrapping phase it is not known if a +- * record at index 0 exists. +- */ +- if (seq != 0) +- seq++; +- } else { +- /* +- * The information about the last finalized sequence number +- * has gone. It should happen only when there is a flood of +- * new messages and the ringbuffer is rapidly recycled. +- * Give up and start from the beginning. +- */ +- seq = 0; +- } ++ /* ++ * Begin searching after the last finalized record. ++ * ++ * On 0, the search must begin at 0 because of hack#2 ++ * of the bootstrapping phase it is not known if a ++ * record at index 0 exists. ++ */ ++ if (seq != 0) ++ seq++; + + /* + * The information about the last finalized @seq might be inaccurate. +@@ -2085,7 +2171,7 @@ void prb_init(struct printk_ringbuffer * + rb->desc_ring.infos = infos; + atomic_long_set(&rb->desc_ring.head_id, DESC0_ID(descbits)); + atomic_long_set(&rb->desc_ring.tail_id, DESC0_ID(descbits)); +- atomic_long_set(&rb->desc_ring.last_finalized_id, DESC0_ID(descbits)); ++ atomic_long_set(&rb->desc_ring.last_finalized_seq, 0); + + rb->text_data_ring.size_bits = textbits; + rb->text_data_ring.data = text_buf; +--- a/kernel/printk/printk_ringbuffer.h ++++ b/kernel/printk/printk_ringbuffer.h +@@ -75,7 +75,7 @@ struct prb_desc_ring { + struct printk_info *infos; + atomic_long_t head_id; + atomic_long_t tail_id; +- atomic_long_t last_finalized_id; ++ atomic_long_t last_finalized_seq; + }; + + /* +@@ -259,7 +259,7 @@ static struct printk_ringbuffer name = { + .infos = &_##name##_infos[0], \ + .head_id = ATOMIC_INIT(DESC0_ID(descbits)), \ + .tail_id = ATOMIC_INIT(DESC0_ID(descbits)), \ +- .last_finalized_id = ATOMIC_INIT(DESC0_ID(descbits)), \ ++ .last_finalized_seq = ATOMIC_INIT(0), \ + }, \ + .text_data_ring = { \ + .size_bits = (avgtextbits) + (descbits), \ diff --git a/debian/patches-rt/0089-printk-ringbuffer-Clarify-special-lpos-values.patch b/debian/patches-rt/0089-printk-ringbuffer-Clarify-special-lpos-values.patch new file mode 100644 index 000000000..397f61984 --- /dev/null +++ b/debian/patches-rt/0089-printk-ringbuffer-Clarify-special-lpos-values.patch @@ -0,0 +1,92 @@ +From: John Ogness +Date: Mon, 23 Oct 2023 11:11:05 +0000 +Subject: [PATCH 089/134] printk: ringbuffer: Clarify special lpos values +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +For empty line records, no data blocks are created. Instead, +these valid records are identified by special logical position +values (in fields of @prb_desc.text_blk_lpos). + +Currently the macro NO_LPOS is used for empty line records. +This name is confusing because it does not imply _why_ there is +no data block. + +Rename NO_LPOS to EMPTY_LINE_LPOS so that it is clear why there +is no data block. + +Also add comments explaining the use of EMPTY_LINE_LPOS as well +as clarification to the values used to represent data-less +blocks. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/printk_ringbuffer.c | 20 ++++++++++++++++---- + kernel/printk/printk_ringbuffer.h | 16 +++++++++++++++- + 2 files changed, 31 insertions(+), 5 deletions(-) + +--- a/kernel/printk/printk_ringbuffer.c ++++ b/kernel/printk/printk_ringbuffer.c +@@ -1034,9 +1034,13 @@ static char *data_alloc(struct printk_ri + unsigned long next_lpos; + + if (size == 0) { +- /* Specify a data-less block. */ +- blk_lpos->begin = NO_LPOS; +- blk_lpos->next = NO_LPOS; ++ /* ++ * Data blocks are not created for empty lines. Instead, the ++ * reader will recognize these special lpos values and handle ++ * it appropriately. ++ */ ++ blk_lpos->begin = EMPTY_LINE_LPOS; ++ blk_lpos->next = EMPTY_LINE_LPOS; + return NULL; + } + +@@ -1214,10 +1218,18 @@ static const char *get_data(struct prb_d + + /* Data-less data block description. */ + if (BLK_DATALESS(blk_lpos)) { +- if (blk_lpos->begin == NO_LPOS && blk_lpos->next == NO_LPOS) { ++ /* ++ * Records that are just empty lines are also valid, even ++ * though they do not have a data block. For such records ++ * explicitly return empty string data to signify success. ++ */ ++ if (blk_lpos->begin == EMPTY_LINE_LPOS && ++ blk_lpos->next == EMPTY_LINE_LPOS) { + *data_size = 0; + return ""; + } ++ ++ /* Data lost, invalid, or otherwise unavailable. */ + return NULL; + } + +--- a/kernel/printk/printk_ringbuffer.h ++++ b/kernel/printk/printk_ringbuffer.h +@@ -127,8 +127,22 @@ enum desc_state { + #define DESC_SV(id, state) (((unsigned long)state << DESC_FLAGS_SHIFT) | id) + #define DESC_ID_MASK (~DESC_FLAGS_MASK) + #define DESC_ID(sv) ((sv) & DESC_ID_MASK) ++ ++/* ++ * Special data block logical position values (for fields of ++ * @prb_desc.text_blk_lpos). ++ * ++ * - Bit0 is used to identify if the record has no data block. (Implemented in ++ * the LPOS_DATALESS() macro.) ++ * ++ * - Bit1 specifies the reason for not having a data block. ++ * ++ * These special values could never be real lpos values because of the ++ * meta data and alignment padding of data blocks. (See to_blk_size() for ++ * details.) ++ */ + #define FAILED_LPOS 0x1 +-#define NO_LPOS 0x3 ++#define EMPTY_LINE_LPOS 0x3 + + #define FAILED_BLK_LPOS \ + { \ diff --git a/debian/patches-rt/0090-printk-For-suppress_panic_printk-check-for-other-CPU.patch b/debian/patches-rt/0090-printk-For-suppress_panic_printk-check-for-other-CPU.patch new file mode 100644 index 000000000..1fb32b1ac --- /dev/null +++ b/debian/patches-rt/0090-printk-For-suppress_panic_printk-check-for-other-CPU.patch @@ -0,0 +1,34 @@ +From: John Ogness +Date: Fri, 13 Oct 2023 20:13:02 +0000 +Subject: [PATCH 090/134] printk: For @suppress_panic_printk check for other + CPU in panic +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Currently @suppress_panic_printk is checked along with +non-matching @panic_cpu and current CPU. This works +because @suppress_panic_printk is only set when +panic_in_progress() is true. + +Rather than relying on the @suppress_panic_printk semantics, +use the concise helper function other_cpu_in_progress(). The +helper function exists to avoid open coding such tests. + +Signed-off-by: John Ogness +Reviewed-by: Petr Mladek +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/printk.c | 3 +-- + 1 file changed, 1 insertion(+), 2 deletions(-) + +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -2271,8 +2271,7 @@ asmlinkage int vprintk_emit(int facility + if (unlikely(suppress_printk)) + return 0; + +- if (unlikely(suppress_panic_printk) && +- atomic_read(&panic_cpu) != raw_smp_processor_id()) ++ if (unlikely(suppress_panic_printk) && other_cpu_in_panic()) + return 0; + + if (level == LOGLEVEL_SCHED) { diff --git a/debian/patches-rt/0091-printk-Add-this_cpu_in_panic.patch b/debian/patches-rt/0091-printk-Add-this_cpu_in_panic.patch new file mode 100644 index 000000000..092591125 --- /dev/null +++ b/debian/patches-rt/0091-printk-Add-this_cpu_in_panic.patch @@ -0,0 +1,88 @@ +From: John Ogness +Date: Fri, 13 Oct 2023 14:30:49 +0000 +Subject: [PATCH 091/134] printk: Add this_cpu_in_panic() +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +There is already panic_in_progress() and other_cpu_in_panic(), +but checking if the current CPU is the panic CPU must still be +open coded. + +Add this_cpu_in_panic() to complete the set. + +Signed-off-by: John Ogness +Reviewed-by: Petr Mladek +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/internal.h | 1 + + kernel/printk/printk.c | 43 +++++++++++++++++++++++-------------------- + 2 files changed, 24 insertions(+), 20 deletions(-) + +--- a/kernel/printk/internal.h ++++ b/kernel/printk/internal.h +@@ -130,6 +130,7 @@ struct printk_message { + }; + + bool other_cpu_in_panic(void); ++bool this_cpu_in_panic(void); + bool printk_get_next_message(struct printk_message *pmsg, u64 seq, + bool is_extended, bool may_supress); + +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -347,6 +347,29 @@ static bool panic_in_progress(void) + return unlikely(atomic_read(&panic_cpu) != PANIC_CPU_INVALID); + } + ++/* Return true if a panic is in progress on the current CPU. */ ++bool this_cpu_in_panic(void) ++{ ++ /* ++ * We can use raw_smp_processor_id() here because it is impossible for ++ * the task to be migrated to the panic_cpu, or away from it. If ++ * panic_cpu has already been set, and we're not currently executing on ++ * that CPU, then we never will be. ++ */ ++ return unlikely(atomic_read(&panic_cpu) == raw_smp_processor_id()); ++} ++ ++/* ++ * Return true if a panic is in progress on a remote CPU. ++ * ++ * On true, the local CPU should immediately release any printing resources ++ * that may be needed by the panic CPU. ++ */ ++bool other_cpu_in_panic(void) ++{ ++ return (panic_in_progress() && !this_cpu_in_panic()); ++} ++ + /* + * This is used for debugging the mess that is the VT code by + * keeping track if we have the console semaphore held. It's +@@ -2593,26 +2616,6 @@ static int console_cpu_notify(unsigned i + return 0; + } + +-/* +- * Return true if a panic is in progress on a remote CPU. +- * +- * On true, the local CPU should immediately release any printing resources +- * that may be needed by the panic CPU. +- */ +-bool other_cpu_in_panic(void) +-{ +- if (!panic_in_progress()) +- return false; +- +- /* +- * We can use raw_smp_processor_id() here because it is impossible for +- * the task to be migrated to the panic_cpu, or away from it. If +- * panic_cpu has already been set, and we're not currently executing on +- * that CPU, then we never will be. +- */ +- return atomic_read(&panic_cpu) != raw_smp_processor_id(); +-} +- + /** + * console_lock - block the console subsystem from printing + * diff --git a/debian/patches-rt/0092-printk-ringbuffer-Cleanup-reader-terminology.patch b/debian/patches-rt/0092-printk-ringbuffer-Cleanup-reader-terminology.patch new file mode 100644 index 000000000..31c6312c4 --- /dev/null +++ b/debian/patches-rt/0092-printk-ringbuffer-Cleanup-reader-terminology.patch @@ -0,0 +1,67 @@ +From: John Ogness +Date: Mon, 6 Nov 2023 15:01:58 +0000 +Subject: [PATCH 092/134] printk: ringbuffer: Cleanup reader terminology +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +With the lockless ringbuffer, it is allowed that multiple +CPUs/contexts write simultaneously into the buffer. This creates +an ambiguity as some writers will finalize sooner. + +The documentation for the prb_read functions is not clear as it +refers to "not yet written" and "no data available". Clarify the +return values and language to be in terms of the reader: records +available for reading. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/printk_ringbuffer.c | 16 +++++++++------- + 1 file changed, 9 insertions(+), 7 deletions(-) + +--- a/kernel/printk/printk_ringbuffer.c ++++ b/kernel/printk/printk_ringbuffer.c +@@ -1987,11 +1987,13 @@ u64 prb_first_seq(struct printk_ringbuff + } + + /* +- * Non-blocking read of a record. Updates @seq to the last finalized record +- * (which may have no data available). ++ * Non-blocking read of a record. + * +- * See the description of prb_read_valid() and prb_read_valid_info() +- * for details. ++ * On success @seq is updated to the record that was read and (if provided) ++ * @r and @line_count will contain the read/calculated data. ++ * ++ * On failure @seq is updated to a record that is not yet available to the ++ * reader, but it will be the next record available to the reader. + */ + static bool _prb_read_valid(struct printk_ringbuffer *rb, u64 *seq, + struct printk_record *r, unsigned int *line_count) +@@ -2010,7 +2012,7 @@ static bool _prb_read_valid(struct print + *seq = tail_seq; + + } else if (err == -ENOENT) { +- /* Record exists, but no data available. Skip. */ ++ /* Record exists, but the data was lost. Skip. */ + (*seq)++; + + } else { +@@ -2043,7 +2045,7 @@ static bool _prb_read_valid(struct print + * On success, the reader must check r->info.seq to see which record was + * actually read. This allows the reader to detect dropped records. + * +- * Failure means @seq refers to a not yet written record. ++ * Failure means @seq refers to a record not yet available to the reader. + */ + bool prb_read_valid(struct printk_ringbuffer *rb, u64 seq, + struct printk_record *r) +@@ -2073,7 +2075,7 @@ bool prb_read_valid(struct printk_ringbu + * On success, the reader must check info->seq to see which record meta data + * was actually read. This allows the reader to detect dropped records. + * +- * Failure means @seq refers to a not yet written record. ++ * Failure means @seq refers to a record not yet available to the reader. + */ + bool prb_read_valid_info(struct printk_ringbuffer *rb, u64 seq, + struct printk_info *info, unsigned int *line_count) diff --git a/debian/patches-rt/0093-printk-Wait-for-all-reserved-records-with-pr_flush.patch b/debian/patches-rt/0093-printk-Wait-for-all-reserved-records-with-pr_flush.patch new file mode 100644 index 000000000..661aea210 --- /dev/null +++ b/debian/patches-rt/0093-printk-Wait-for-all-reserved-records-with-pr_flush.patch @@ -0,0 +1,170 @@ +From: John Ogness +Date: Mon, 6 Nov 2023 14:59:55 +0000 +Subject: [PATCH 093/134] printk: Wait for all reserved records with pr_flush() +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Currently pr_flush() will only wait for records that were +available to readers at the time of the call (using +prb_next_seq()). But there may be more records (non-finalized) +that have following finalized records. pr_flush() should wait +for these to print as well. Particularly because any trailing +finalized records may be the messages that the calling context +wants to ensure are printed. + +Add a new ringbuffer function prb_next_reserve_seq() to return +the sequence number following the most recently reserved record. +This guarantees that pr_flush() will wait until all current +printk() messages (completed or in progress) have been printed. + +Fixes: 3b604ca81202 ("printk: add pr_flush()") +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/printk.c | 2 + kernel/printk/printk_ringbuffer.c | 113 ++++++++++++++++++++++++++++++++++++++ + kernel/printk/printk_ringbuffer.h | 1 + 3 files changed, 115 insertions(+), 1 deletion(-) + +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -3756,7 +3756,7 @@ static bool __pr_flush(struct console *c + + might_sleep(); + +- seq = prb_next_seq(prb); ++ seq = prb_next_reserve_seq(prb); + + /* Flush the consoles so that records up to @seq are printed. */ + console_lock(); +--- a/kernel/printk/printk_ringbuffer.c ++++ b/kernel/printk/printk_ringbuffer.c +@@ -1986,6 +1986,119 @@ u64 prb_first_seq(struct printk_ringbuff + return seq; + } + ++/** ++ * prb_next_reserve_seq() - Get the sequence number after the most recently ++ * reserved record. ++ * ++ * @rb: The ringbuffer to get the sequence number from. ++ * ++ * This is the public function available to readers to see what sequence ++ * number will be assigned to the next reserved record. ++ * ++ * Note that depending on the situation, this value can be equal to or ++ * higher than the sequence number returned by prb_next_seq(). ++ * ++ * Context: Any context. ++ * Return: The sequence number that will be assigned to the next record ++ * reserved. ++ */ ++u64 prb_next_reserve_seq(struct printk_ringbuffer *rb) ++{ ++ struct prb_desc_ring *desc_ring = &rb->desc_ring; ++ unsigned long last_finalized_id; ++ atomic_long_t *state_var; ++ u64 last_finalized_seq; ++ unsigned long head_id; ++ struct prb_desc desc; ++ unsigned long diff; ++ struct prb_desc *d; ++ int err; ++ ++ /* ++ * It may not be possible to read a sequence number for @head_id. ++ * So the ID of @last_finailzed_seq is used to calculate what the ++ * sequence number of @head_id will be. ++ */ ++ ++try_again: ++ last_finalized_seq = desc_last_finalized_seq(rb); ++ ++ /* ++ * @head_id is loaded after @last_finalized_seq to ensure that it is ++ * at or beyond @last_finalized_seq. ++ * ++ * Memory barrier involvement: ++ * ++ * If desc_last_finalized_seq:A reads from ++ * desc_update_last_finalized:A, then ++ * prb_next_reserve_seq:A reads from desc_reserve:D. ++ * ++ * Relies on: ++ * ++ * RELEASE from desc_reserve:D to desc_update_last_finalized:A ++ * matching ++ * ACQUIRE from desc_last_finalized_seq:A to prb_next_reserve_seq:A ++ * ++ * Note: desc_reserve:D and desc_update_last_finalized:A can be ++ * different CPUs. However, the desc_update_last_finalized:A CPU ++ * (which performs the release) must have previously seen ++ * desc_read:C, which implies desc_reserve:D can be seen. ++ */ ++ head_id = atomic_long_read(&desc_ring->head_id); /* LMM(prb_next_reserve_seq:A) */ ++ ++ d = to_desc(desc_ring, last_finalized_seq); ++ state_var = &d->state_var; ++ ++ /* Extract the ID, used to specify the descriptor to read. */ ++ last_finalized_id = DESC_ID(atomic_long_read(state_var)); ++ ++ /* Ensure @last_finalized_id is correct. */ ++ err = desc_read_finalized_seq(desc_ring, last_finalized_id, last_finalized_seq, &desc); ++ ++ if (err == -EINVAL) { ++ if (last_finalized_seq == 0) { ++ /* ++ * @last_finalized_seq still contains its initial ++ * value. Probably no record has been finalized yet. ++ * This means the ringbuffer is not yet full and the ++ * @head_id value can be used directly (subtracting ++ * off the id value corresponding to seq=0). ++ */ ++ ++ /* ++ * Because of hack#2 of the bootstrapping phase, the ++ * @head_id initial value must be handled separately. ++ */ ++ if (head_id == DESC0_ID(desc_ring->count_bits)) ++ return 0; ++ ++ /* ++ * The @head_id is initialized such that the first ++ * increment will yield the first record (seq=0). ++ * Therefore use the initial value +1 as the base to ++ * subtract from @head_id. ++ */ ++ last_finalized_id = DESC0_ID(desc_ring->count_bits) + 1; ++ } else { ++ /* Record must have been overwritten. Try again. */ ++ goto try_again; ++ } ++ } ++ ++ /* ++ * @diff is the number of records beyond the last record available ++ * to readers. ++ */ ++ diff = head_id - last_finalized_id; ++ ++ /* ++ * @head_id points to the most recently reserved record, but this ++ * function returns the sequence number that will be assigned to the ++ * next (not yet reserved) record. Thus +1 is needed. ++ */ ++ return (last_finalized_seq + diff + 1); ++} ++ + /* + * Non-blocking read of a record. + * +--- a/kernel/printk/printk_ringbuffer.h ++++ b/kernel/printk/printk_ringbuffer.h +@@ -395,6 +395,7 @@ bool prb_read_valid_info(struct printk_r + u64 prb_first_seq(struct printk_ringbuffer *rb); + u64 prb_first_valid_seq(struct printk_ringbuffer *rb); + u64 prb_next_seq(struct printk_ringbuffer *rb); ++u64 prb_next_reserve_seq(struct printk_ringbuffer *rb); + + #ifdef CONFIG_64BIT + diff --git a/debian/patches-rt/0094-printk-ringbuffer-Skip-non-finalized-records-in-pani.patch b/debian/patches-rt/0094-printk-ringbuffer-Skip-non-finalized-records-in-pani.patch new file mode 100644 index 000000000..56c675cea --- /dev/null +++ b/debian/patches-rt/0094-printk-ringbuffer-Skip-non-finalized-records-in-pani.patch @@ -0,0 +1,68 @@ +From: John Ogness +Date: Fri, 13 Oct 2023 10:23:11 +0000 +Subject: [PATCH 094/134] printk: ringbuffer: Skip non-finalized records in + panic +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Normally a reader will stop once reaching a non-finalized +record. However, when a panic happens, writers from other CPUs +(or an interrupted context on the panic CPU) may have been +writing a record and were unable to finalize it. The panic CPU +will reserve/commit/finalize its panic records, but these will +be located after the non-finalized records. This results in +panic() not flushing the panic messages. + +Extend _prb_read_valid() to skip over non-finalized records if +on the panic CPU. + +Fixes: 896fbe20b4e2 ("printk: use the lockless ringbuffer") +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/printk_ringbuffer.c | 28 ++++++++++++++++++++++++++-- + 1 file changed, 26 insertions(+), 2 deletions(-) + +--- a/kernel/printk/printk_ringbuffer.c ++++ b/kernel/printk/printk_ringbuffer.c +@@ -2107,6 +2107,10 @@ u64 prb_next_reserve_seq(struct printk_r + * + * On failure @seq is updated to a record that is not yet available to the + * reader, but it will be the next record available to the reader. ++ * ++ * Note: When the current CPU is in panic, this function will skip over any ++ * non-existent/non-finalized records in order to allow the panic CPU ++ * to print any and all records that have been finalized. + */ + static bool _prb_read_valid(struct printk_ringbuffer *rb, u64 *seq, + struct printk_record *r, unsigned int *line_count) +@@ -2129,8 +2133,28 @@ static bool _prb_read_valid(struct print + (*seq)++; + + } else { +- /* Non-existent/non-finalized record. Must stop. */ +- return false; ++ /* ++ * Non-existent/non-finalized record. Must stop. ++ * ++ * For panic situations it cannot be expected that ++ * non-finalized records will become finalized. But ++ * there may be other finalized records beyond that ++ * need to be printed for a panic situation. If this ++ * is the panic CPU, skip this ++ * non-existent/non-finalized record unless it is ++ * at or beyond the head, in which case it is not ++ * possible to continue. ++ * ++ * Note that new messages printed on panic CPU are ++ * finalized when we are here. The only exception ++ * might be the last message without trailing newline. ++ * But it would have the sequence number returned ++ * by "prb_next_reserve_seq() - 1". ++ */ ++ if (this_cpu_in_panic() && ((*seq + 1) < prb_next_reserve_seq(rb))) ++ (*seq)++; ++ else ++ return false; + } + } + diff --git a/debian/patches-rt/0095-printk-ringbuffer-Consider-committed-as-finalized-in.patch b/debian/patches-rt/0095-printk-ringbuffer-Consider-committed-as-finalized-in.patch new file mode 100644 index 000000000..932ba13e7 --- /dev/null +++ b/debian/patches-rt/0095-printk-ringbuffer-Consider-committed-as-finalized-in.patch @@ -0,0 +1,62 @@ +From: John Ogness +Date: Mon, 20 Nov 2023 12:46:35 +0100 +Subject: [PATCH 095/134] printk: ringbuffer: Consider committed as finalized + in panic +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +A descriptor in the committed state means the record does not yet +exist for the reader. However, for the panic CPU, committed +records should be handled as finalized records since they contain +message data in a consistent state and may contain additional +hints as to the cause of the panic. + +Add an exception for records in the commit state to not be +considered non-existing when reading from the panic CPU. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/printk_ringbuffer.c | 17 ++++++++++++++--- + 1 file changed, 14 insertions(+), 3 deletions(-) + +--- a/kernel/printk/printk_ringbuffer.c ++++ b/kernel/printk/printk_ringbuffer.c +@@ -1857,6 +1857,8 @@ static bool copy_data(struct prb_data_ri + * descriptor. However, it also verifies that the record is finalized and has + * the sequence number @seq. On success, 0 is returned. + * ++ * For the panic CPU, committed descriptors are also considered finalized. ++ * + * Error return values: + * -EINVAL: A finalized record with sequence number @seq does not exist. + * -ENOENT: A finalized record with sequence number @seq exists, but its data +@@ -1875,17 +1877,26 @@ static int desc_read_finalized_seq(struc + + /* + * An unexpected @id (desc_miss) or @seq mismatch means the record +- * does not exist. A descriptor in the reserved or committed state +- * means the record does not yet exist for the reader. ++ * does not exist. A descriptor in the reserved state means the ++ * record does not yet exist for the reader. + */ + if (d_state == desc_miss || + d_state == desc_reserved || +- d_state == desc_committed || + s != seq) { + return -EINVAL; + } + + /* ++ * A descriptor in the committed state means the record does not yet ++ * exist for the reader. However, for the panic CPU, committed ++ * records are also handled as finalized records since they contain ++ * message data in a consistent state and may contain additional ++ * hints as to the cause of the panic. ++ */ ++ if (d_state == desc_committed && !this_cpu_in_panic()) ++ return -EINVAL; ++ ++ /* + * A descriptor in the reusable state may no longer have its data + * available; report it as existing but with lost data. Or the record + * may actually be a record with lost data. diff --git a/debian/patches-rt/0096-printk-Disable-passing-console-lock-owner-completely.patch b/debian/patches-rt/0096-printk-Disable-passing-console-lock-owner-completely.patch new file mode 100644 index 000000000..d5dcdcdcc --- /dev/null +++ b/debian/patches-rt/0096-printk-Disable-passing-console-lock-owner-completely.patch @@ -0,0 +1,107 @@ +From: Petr Mladek +Date: Fri, 13 Oct 2023 14:12:05 +0000 +Subject: [PATCH 096/134] printk: Disable passing console lock owner completely + during panic() +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +The commit d51507098ff91 ("printk: disable optimistic spin +during panic") added checks to avoid becoming a console waiter +if a panic is in progress. + +However, the transition to panic can occur while there is +already a waiter. The current owner should not pass the lock to +the waiter because it might get stopped or blocked anytime. + +Also the panic context might pass the console lock owner to an +already stopped waiter by mistake. It might happen when +console_flush_on_panic() ignores the current lock owner, for +example: + +CPU0 CPU1 +---- ---- +console_lock_spinning_enable() + console_trylock_spinning() + [CPU1 now console waiter] +NMI: panic() + panic_other_cpus_shutdown() + [stopped as console waiter] + console_flush_on_panic() + console_lock_spinning_enable() + [print 1 record] + console_lock_spinning_disable_and_check() + [handover to stopped CPU1] + +This results in panic() not flushing the panic messages. + +Fix these problems by disabling all spinning operations +completely during panic(). + +Another advantage is that it prevents possible deadlocks caused +by "console_owner_lock". The panic() context does not need to +take it any longer. The lockless checks are safe because the +functions become NOPs when they see the panic in progress. All +operations manipulating the state are still synchronized by the +lock even when non-panic CPUs would notice the panic +synchronously. + +The current owner might stay spinning. But non-panic() CPUs +would get stopped anyway and the panic context will never start +spinning. + +Fixes: dbdda842fe96 ("printk: Add console owner and waiter logic to load balance console writes") +Signed-off-by: Petr Mladek +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/printk.c | 29 +++++++++++++++++++++++++++++ + 1 file changed, 29 insertions(+) + +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -1870,10 +1870,23 @@ static bool console_waiter; + */ + static void console_lock_spinning_enable(void) + { ++ /* ++ * Do not use spinning in panic(). The panic CPU wants to keep the lock. ++ * Non-panic CPUs abandon the flush anyway. ++ * ++ * Just keep the lockdep annotation. The panic-CPU should avoid ++ * taking console_owner_lock because it might cause a deadlock. ++ * This looks like the easiest way how to prevent false lockdep ++ * reports without handling races a lockless way. ++ */ ++ if (panic_in_progress()) ++ goto lockdep; ++ + raw_spin_lock(&console_owner_lock); + console_owner = current; + raw_spin_unlock(&console_owner_lock); + ++lockdep: + /* The waiter may spin on us after setting console_owner */ + spin_acquire(&console_owner_dep_map, 0, 0, _THIS_IP_); + } +@@ -1898,6 +1911,22 @@ static int console_lock_spinning_disable + { + int waiter; + ++ /* ++ * Ignore spinning waiters during panic() because they might get stopped ++ * or blocked at any time, ++ * ++ * It is safe because nobody is allowed to start spinning during panic ++ * in the first place. If there has been a waiter then non panic CPUs ++ * might stay spinning. They would get stopped anyway. The panic context ++ * will never start spinning and an interrupted spin on panic CPU will ++ * never continue. ++ */ ++ if (panic_in_progress()) { ++ /* Keep lockdep happy. */ ++ spin_release(&console_owner_dep_map, _THIS_IP_); ++ return 0; ++ } ++ + raw_spin_lock(&console_owner_lock); + waiter = READ_ONCE(console_waiter); + console_owner = NULL; diff --git a/debian/patches-rt/0097-printk-Avoid-non-panic-CPUs-writing-to-ringbuffer.patch b/debian/patches-rt/0097-printk-Avoid-non-panic-CPUs-writing-to-ringbuffer.patch new file mode 100644 index 000000000..2f5a4ba17 --- /dev/null +++ b/debian/patches-rt/0097-printk-Avoid-non-panic-CPUs-writing-to-ringbuffer.patch @@ -0,0 +1,78 @@ +From: John Ogness +Date: Fri, 20 Oct 2023 09:37:05 +0000 +Subject: [PATCH 097/134] printk: Avoid non-panic CPUs writing to ringbuffer +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Commit 13fb0f74d702 ("printk: Avoid livelock with heavy printk +during panic") introduced a mechanism to silence non-panic CPUs +if too many messages are being dropped. Aside from trying to +workaround the livelock bugs of legacy consoles, it was also +intended to avoid losing panic messages. However, if non-panic +CPUs are writing to the ringbuffer, then reacting to dropped +messages is too late. + +To avoid losing panic CPU messages, silence non-panic CPUs +immediately on panic. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/printk.c | 26 ++++++-------------------- + 1 file changed, 6 insertions(+), 20 deletions(-) + +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -462,12 +462,6 @@ static int console_msg_format = MSG_FORM + static DEFINE_MUTEX(syslog_lock); + + #ifdef CONFIG_PRINTK +-/* +- * During panic, heavy printk by other CPUs can delay the +- * panic and risk deadlock on console resources. +- */ +-static int __read_mostly suppress_panic_printk; +- + DECLARE_WAIT_QUEUE_HEAD(log_wait); + /* All 3 protected by @syslog_lock. */ + /* the next printk record to read by syslog(READ) or /proc/kmsg */ +@@ -2323,7 +2317,12 @@ asmlinkage int vprintk_emit(int facility + if (unlikely(suppress_printk)) + return 0; + +- if (unlikely(suppress_panic_printk) && other_cpu_in_panic()) ++ /* ++ * The messages on the panic CPU are the most important. If ++ * non-panic CPUs are generating any messages, they will be ++ * silently dropped. ++ */ ++ if (other_cpu_in_panic()) + return 0; + + if (level == LOGLEVEL_SCHED) { +@@ -2800,8 +2799,6 @@ void console_prepend_dropped(struct prin + bool printk_get_next_message(struct printk_message *pmsg, u64 seq, + bool is_extended, bool may_suppress) + { +- static int panic_console_dropped; +- + struct printk_buffers *pbufs = pmsg->pbufs; + const size_t scratchbuf_sz = sizeof(pbufs->scratchbuf); + const size_t outbuf_sz = sizeof(pbufs->outbuf); +@@ -2829,17 +2826,6 @@ bool printk_get_next_message(struct prin + pmsg->seq = r.info->seq; + pmsg->dropped = r.info->seq - seq; + +- /* +- * Check for dropped messages in panic here so that printk +- * suppression can occur as early as possible if necessary. +- */ +- if (pmsg->dropped && +- panic_in_progress() && +- panic_console_dropped++ > 10) { +- suppress_panic_printk = 1; +- pr_warn_once("Too many dropped messages. Suppress messages on non-panic CPUs to prevent livelock.\n"); +- } +- + /* Skip record that has level above the console loglevel. */ + if (may_suppress && suppress_message_printing(r.info->level)) + goto out; diff --git a/debian/patches-rt/0098-panic-Flush-kernel-log-buffer-at-the-end.patch b/debian/patches-rt/0098-panic-Flush-kernel-log-buffer-at-the-end.patch new file mode 100644 index 000000000..ec3cbc5dd --- /dev/null +++ b/debian/patches-rt/0098-panic-Flush-kernel-log-buffer-at-the-end.patch @@ -0,0 +1,38 @@ +From: John Ogness +Date: Thu, 14 Dec 2023 20:48:23 +0000 +Subject: [PATCH 098/134] panic: Flush kernel log buffer at the end +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +If the kernel crashes in a context where printk() calls always +defer printing (such as in NMI or inside a printk_safe section) +then the final panic messages will be deferred to irq_work. But +if irq_work is not available, the messages will not get printed +unless explicitly flushed. The result is that the final +"end Kernel panic" banner does not get printed. + +Add one final flush after the last printk() call to make sure +the final panic messages make it out as well. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/panic.c | 8 ++++++++ + 1 file changed, 8 insertions(+) + +--- a/kernel/panic.c ++++ b/kernel/panic.c +@@ -442,6 +442,14 @@ void panic(const char *fmt, ...) + + /* Do not scroll important messages printed above */ + suppress_printk = 1; ++ ++ /* ++ * The final messages may not have been printed if in a context that ++ * defers printing (such as NMI) and irq_work is not available. ++ * Explicitly flush the kernel log buffer one last time. ++ */ ++ console_flush_on_panic(CONSOLE_FLUSH_PENDING); ++ + local_irq_enable(); + for (i = 0; ; i += PANIC_TIMER_STEP) { + touch_softlockup_watchdog(); diff --git a/debian/patches-rt/0099-printk-Consider-nbcon-boot-consoles-on-seq-init.patch b/debian/patches-rt/0099-printk-Consider-nbcon-boot-consoles-on-seq-init.patch new file mode 100644 index 000000000..b4e61c768 --- /dev/null +++ b/debian/patches-rt/0099-printk-Consider-nbcon-boot-consoles-on-seq-init.patch @@ -0,0 +1,51 @@ +From: John Ogness +Date: Wed, 22 Nov 2023 11:23:43 +0000 +Subject: [PATCH 099/134] printk: Consider nbcon boot consoles on seq init +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +If a non-boot console is registering and boot consoles exist, the +consoles are flushed before being unregistered. This allows the +non-boot console to continue where the boot console left off. + +If for whatever reason flushing fails, the lowest seq found from +any of the enabled boot consoles is used. Until now con->seq was +checked. However, if it is an nbcon boot console, the function +nbcon_seq_read() must be used to read seq because con->seq is +always 0. + +Check if it is an nbcon boot console and if so call +nbcon_seq_read() to read seq. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/printk.c | 17 +++++++++++++---- + 1 file changed, 13 insertions(+), 4 deletions(-) + +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -3392,11 +3392,20 @@ static void console_init_seq(struct cons + + newcon->seq = prb_next_seq(prb); + for_each_console(con) { +- if ((con->flags & CON_BOOT) && +- (con->flags & CON_ENABLED) && +- con->seq < newcon->seq) { +- newcon->seq = con->seq; ++ u64 seq; ++ ++ if (!((con->flags & CON_BOOT) && ++ (con->flags & CON_ENABLED))) { ++ continue; + } ++ ++ if (con->flags & CON_NBCON) ++ seq = nbcon_seq_read(con); ++ else ++ seq = con->seq; ++ ++ if (seq < newcon->seq) ++ newcon->seq = seq; + } + } + diff --git a/debian/patches-rt/0100-printk-Add-sparse-notation-to-console_srcu-locking.patch b/debian/patches-rt/0100-printk-Add-sparse-notation-to-console_srcu-locking.patch new file mode 100644 index 000000000..8a1473c93 --- /dev/null +++ b/debian/patches-rt/0100-printk-Add-sparse-notation-to-console_srcu-locking.patch @@ -0,0 +1,36 @@ +From: John Ogness +Date: Mon, 9 Oct 2023 13:55:19 +0000 +Subject: [PATCH 100/134] printk: Add sparse notation to console_srcu locking +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +kernel/printk/printk.c:284:5: sparse: sparse: context imbalance in +'console_srcu_read_lock' - wrong count at exit +include/linux/srcu.h:301:9: sparse: sparse: context imbalance in +'console_srcu_read_unlock' - unexpected unlock + +Reported-by: kernel test robot +Fixes: 6c4afa79147e ("printk: Prepare for SRCU console list protection") +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/printk.c | 2 ++ + 1 file changed, 2 insertions(+) + +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -282,6 +282,7 @@ EXPORT_SYMBOL(console_list_unlock); + * Return: A cookie to pass to console_srcu_read_unlock(). + */ + int console_srcu_read_lock(void) ++ __acquires(&console_srcu) + { + return srcu_read_lock_nmisafe(&console_srcu); + } +@@ -295,6 +296,7 @@ EXPORT_SYMBOL(console_srcu_read_lock); + * Counterpart to console_srcu_read_lock() + */ + void console_srcu_read_unlock(int cookie) ++ __releases(&console_srcu) + { + srcu_read_unlock_nmisafe(&console_srcu, cookie); + } diff --git a/debian/patches-rt/0101-printk-nbcon-Ensure-ownership-release-on-failed-emit.patch b/debian/patches-rt/0101-printk-nbcon-Ensure-ownership-release-on-failed-emit.patch new file mode 100644 index 000000000..d96f2dc2b --- /dev/null +++ b/debian/patches-rt/0101-printk-nbcon-Ensure-ownership-release-on-failed-emit.patch @@ -0,0 +1,58 @@ +From: John Ogness +Date: Fri, 20 Oct 2023 09:52:59 +0000 +Subject: [PATCH 101/134] printk: nbcon: Ensure ownership release on failed + emit +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Until now it was assumed that ownership has been lost when the +write_atomic() callback fails. nbcon_emit_next_record() only +returns false when ownership has been lost. + +Ensure ownership has been lost before reporting failure by +explicitly attempting a release. If the current context is not +the owner, the release has no effect. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/nbcon.c | 19 ++++++++++--------- + 1 file changed, 10 insertions(+), 9 deletions(-) + +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -852,7 +852,7 @@ static bool nbcon_emit_next_record(struc + unsigned long con_dropped; + struct nbcon_state cur; + unsigned long dropped; +- bool done; ++ bool done = false; + + /* + * The printk buffers are filled within an unsafe section. This +@@ -891,17 +891,18 @@ static bool nbcon_emit_next_record(struc + nbcon_state_read(con, &cur); + wctxt->unsafe_takeover = cur.unsafe_takeover; + +- if (con->write_atomic) { ++ if (con->write_atomic) + done = con->write_atomic(con, wctxt); +- } else { +- nbcon_context_release(ctxt); +- WARN_ON_ONCE(1); +- done = false; +- } + +- /* If not done, the emit was aborted. */ +- if (!done) ++ if (!done) { ++ /* ++ * The emit was aborted, probably due to a loss of ownership. ++ * Ensure ownership was lost or released before reporting the ++ * loss. ++ */ ++ nbcon_context_release(ctxt); + return false; ++ } + + /* + * Since any dropped message was successfully output, reset the diff --git a/debian/patches-rt/0102-printk-Check-printk_deferred_enter-_exit-usage.patch b/debian/patches-rt/0102-printk-Check-printk_deferred_enter-_exit-usage.patch new file mode 100644 index 000000000..2e1d736ea --- /dev/null +++ b/debian/patches-rt/0102-printk-Check-printk_deferred_enter-_exit-usage.patch @@ -0,0 +1,58 @@ +From: Sebastian Andrzej Siewior +Date: Fri, 22 Sep 2023 14:58:18 +0000 +Subject: [PATCH 102/134] printk: Check printk_deferred_enter()/_exit() usage +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Add validation that printk_deferred_enter()/_exit() are called in +non-migration contexts. + +Signed-off-by: Sebastian Andrzej Siewior +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/printk.h | 7 +++++-- + kernel/printk/printk_safe.c | 12 ++++++++++++ + 2 files changed, 17 insertions(+), 2 deletions(-) + +--- a/include/linux/printk.h ++++ b/include/linux/printk.h +@@ -159,13 +159,16 @@ int _printk(const char *fmt, ...); + + extern void __printk_safe_enter(void); + extern void __printk_safe_exit(void); ++extern void __printk_deferred_enter(void); ++extern void __printk_deferred_exit(void); ++ + /* + * The printk_deferred_enter/exit macros are available only as a hack for + * some code paths that need to defer all printk console printing. Interrupts + * must be disabled for the deferred duration. + */ +-#define printk_deferred_enter __printk_safe_enter +-#define printk_deferred_exit __printk_safe_exit ++#define printk_deferred_enter() __printk_deferred_enter() ++#define printk_deferred_exit() __printk_deferred_exit() + + /* + * Please don't use printk_ratelimit(), because it shares ratelimiting state +--- a/kernel/printk/printk_safe.c ++++ b/kernel/printk/printk_safe.c +@@ -26,6 +26,18 @@ void __printk_safe_exit(void) + this_cpu_dec(printk_context); + } + ++void __printk_deferred_enter(void) ++{ ++ cant_migrate(); ++ this_cpu_inc(printk_context); ++} ++ ++void __printk_deferred_exit(void) ++{ ++ cant_migrate(); ++ this_cpu_dec(printk_context); ++} ++ + asmlinkage int vprintk(const char *fmt, va_list args) + { + #ifdef CONFIG_KGDB_KDB diff --git a/debian/patches-rt/0103-printk-nbcon-Implement-processing-in-port-lock-wrapp.patch b/debian/patches-rt/0103-printk-nbcon-Implement-processing-in-port-lock-wrapp.patch new file mode 100644 index 000000000..cee70cb44 --- /dev/null +++ b/debian/patches-rt/0103-printk-nbcon-Implement-processing-in-port-lock-wrapp.patch @@ -0,0 +1,244 @@ +From: John Ogness +Date: Wed, 13 Sep 2023 08:35:23 +0000 +Subject: [PATCH 103/134] printk: nbcon: Implement processing in port->lock + wrapper +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Currently the port->lock wrappers uart_port_lock(), +uart_port_unlock() (and their variants) only lock/unlock +the spin_lock. + +If the port is an nbcon console, the wrappers must also +acquire/release the console and mark the region as unsafe. This +allows general port->lock synchronization to be synchronized +with the nbcon console ownership. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/console.h | 2 + + include/linux/printk.h | 13 +++++++ + include/linux/serial_core.h | 18 +++++++++- + kernel/printk/nbcon.c | 77 ++++++++++++++++++++++++++++++++++++++++++++ + 4 files changed, 108 insertions(+), 2 deletions(-) + +--- a/include/linux/console.h ++++ b/include/linux/console.h +@@ -299,6 +299,7 @@ struct nbcon_write_context { + * @nbcon_state: State for nbcon consoles + * @nbcon_seq: Sequence number of the next record for nbcon to print + * @pbufs: Pointer to nbcon private buffer ++ * @locked_port: True, if the port lock is locked by nbcon + */ + struct console { + char name[16]; +@@ -325,6 +326,7 @@ struct console { + atomic_t __private nbcon_state; + atomic_long_t __private nbcon_seq; + struct printk_buffers *pbufs; ++ bool locked_port; + }; + + #ifdef CONFIG_LOCKDEP +--- a/include/linux/printk.h ++++ b/include/linux/printk.h +@@ -9,6 +9,8 @@ + #include + #include + ++struct uart_port; ++ + extern const char linux_banner[]; + extern const char linux_proc_banner[]; + +@@ -195,6 +197,8 @@ void show_regs_print_info(const char *lo + extern asmlinkage void dump_stack_lvl(const char *log_lvl) __cold; + extern asmlinkage void dump_stack(void) __cold; + void printk_trigger_flush(void); ++extern void nbcon_acquire(struct uart_port *up); ++extern void nbcon_release(struct uart_port *up); + #else + static inline __printf(1, 0) + int vprintk(const char *s, va_list args) +@@ -274,6 +278,15 @@ static inline void dump_stack(void) + static inline void printk_trigger_flush(void) + { + } ++ ++static inline void nbcon_acquire(struct uart_port *up) ++{ ++} ++ ++static inline void nbcon_release(struct uart_port *up) ++{ ++} ++ + #endif + + #ifdef CONFIG_SMP +--- a/include/linux/serial_core.h ++++ b/include/linux/serial_core.h +@@ -595,6 +595,7 @@ struct uart_port { + static inline void uart_port_lock(struct uart_port *up) + { + spin_lock(&up->lock); ++ nbcon_acquire(up); + } + + /** +@@ -604,6 +605,7 @@ static inline void uart_port_lock(struct + static inline void uart_port_lock_irq(struct uart_port *up) + { + spin_lock_irq(&up->lock); ++ nbcon_acquire(up); + } + + /** +@@ -614,6 +616,7 @@ static inline void uart_port_lock_irq(st + static inline void uart_port_lock_irqsave(struct uart_port *up, unsigned long *flags) + { + spin_lock_irqsave(&up->lock, *flags); ++ nbcon_acquire(up); + } + + /** +@@ -624,7 +627,11 @@ static inline void uart_port_lock_irqsav + */ + static inline bool uart_port_trylock(struct uart_port *up) + { +- return spin_trylock(&up->lock); ++ if (!spin_trylock(&up->lock)) ++ return false; ++ ++ nbcon_acquire(up); ++ return true; + } + + /** +@@ -636,7 +643,11 @@ static inline bool uart_port_trylock(str + */ + static inline bool uart_port_trylock_irqsave(struct uart_port *up, unsigned long *flags) + { +- return spin_trylock_irqsave(&up->lock, *flags); ++ if (!spin_trylock_irqsave(&up->lock, *flags)) ++ return false; ++ ++ nbcon_acquire(up); ++ return true; + } + + /** +@@ -645,6 +656,7 @@ static inline bool uart_port_trylock_irq + */ + static inline void uart_port_unlock(struct uart_port *up) + { ++ nbcon_release(up); + spin_unlock(&up->lock); + } + +@@ -654,6 +666,7 @@ static inline void uart_port_unlock(stru + */ + static inline void uart_port_unlock_irq(struct uart_port *up) + { ++ nbcon_release(up); + spin_unlock_irq(&up->lock); + } + +@@ -664,6 +677,7 @@ static inline void uart_port_unlock_irq( + */ + static inline void uart_port_unlock_irqrestore(struct uart_port *up, unsigned long flags) + { ++ nbcon_release(up); + spin_unlock_irqrestore(&up->lock, flags); + } + +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -6,6 +6,7 @@ + #include + #include + #include ++#include + #include "internal.h" + /* + * Printk console printing implementation for consoles which does not depend +@@ -995,3 +996,79 @@ void nbcon_free(struct console *con) + + con->pbufs = NULL; + } ++ ++static inline bool uart_is_nbcon(struct uart_port *up) ++{ ++ int cookie; ++ bool ret; ++ ++ if (!uart_console(up)) ++ return false; ++ ++ cookie = console_srcu_read_lock(); ++ ret = (console_srcu_read_flags(up->cons) & CON_NBCON); ++ console_srcu_read_unlock(cookie); ++ return ret; ++} ++ ++/** ++ * nbcon_acquire - The second half of the port locking wrapper ++ * @up: The uart port whose @lock was locked ++ * ++ * The uart_port_lock() wrappers will first lock the spin_lock @up->lock. ++ * Then this function is called to implement nbcon-specific processing. ++ * ++ * If @up is an nbcon console, this console will be acquired and marked as ++ * unsafe. Otherwise this function does nothing. ++ */ ++void nbcon_acquire(struct uart_port *up) ++{ ++ struct console *con = up->cons; ++ struct nbcon_context ctxt; ++ ++ if (!uart_is_nbcon(up)) ++ return; ++ ++ WARN_ON_ONCE(con->locked_port); ++ ++ do { ++ do { ++ memset(&ctxt, 0, sizeof(ctxt)); ++ ctxt.console = con; ++ ctxt.prio = NBCON_PRIO_NORMAL; ++ } while (!nbcon_context_try_acquire(&ctxt)); ++ ++ } while (!nbcon_context_enter_unsafe(&ctxt)); ++ ++ con->locked_port = true; ++} ++EXPORT_SYMBOL_GPL(nbcon_acquire); ++ ++/** ++ * nbcon_release - The first half of the port unlocking wrapper ++ * @up: The uart port whose @lock is about to be unlocked ++ * ++ * The uart_port_unlock() wrappers will first call this function to implement ++ * nbcon-specific processing. Then afterwards the uart_port_unlock() wrappers ++ * will unlock the spin_lock @up->lock. ++ * ++ * If @up is an nbcon console, the console will be marked as safe and ++ * released. Otherwise this function does nothing. ++ */ ++void nbcon_release(struct uart_port *up) ++{ ++ struct console *con = up->cons; ++ struct nbcon_context ctxt = { ++ .console = con, ++ .prio = NBCON_PRIO_NORMAL, ++ }; ++ ++ if (!con->locked_port) ++ return; ++ ++ if (nbcon_context_exit_unsafe(&ctxt)) ++ nbcon_context_release(&ctxt); ++ ++ con->locked_port = false; ++} ++EXPORT_SYMBOL_GPL(nbcon_release); diff --git a/debian/patches-rt/0104-printk-nbcon-Add-driver_enter-driver_exit-console-ca.patch b/debian/patches-rt/0104-printk-nbcon-Add-driver_enter-driver_exit-console-ca.patch new file mode 100644 index 000000000..d314cb53d --- /dev/null +++ b/debian/patches-rt/0104-printk-nbcon-Add-driver_enter-driver_exit-console-ca.patch @@ -0,0 +1,42 @@ +From: John Ogness +Date: Fri, 8 Dec 2023 15:54:27 +0000 +Subject: [PATCH 104/134] printk: nbcon: Add driver_enter/driver_exit console + callbacks +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Console drivers need some mechanism to synchronize between "normal +driver activity" and console printing. For uart serial drivers it +is the port lock. Other types of console drivers (network, +graphics, USB) will need something as well. + +Provide 2 new mandatory nbcon console callbacks (driver_enter and +driver_exit) to allow the consoles drivers to implement the +appropriate synchronization. The callbacks are also expected to +disable/enable migration. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/console.h | 4 ++++ + 1 file changed, 4 insertions(+) + +--- a/include/linux/console.h ++++ b/include/linux/console.h +@@ -296,6 +296,8 @@ struct nbcon_write_context { + * @node: hlist node for the console list + * + * @write_atomic: Write callback for atomic context ++ * @driver_enter: Callback to begin synchronization with driver code ++ * @driver_exit: Callback to finish synchronization with driver code + * @nbcon_state: State for nbcon consoles + * @nbcon_seq: Sequence number of the next record for nbcon to print + * @pbufs: Pointer to nbcon private buffer +@@ -323,6 +325,8 @@ struct console { + /* nbcon console specific members */ + bool (*write_atomic)(struct console *con, + struct nbcon_write_context *wctxt); ++ void (*driver_enter)(struct console *con, unsigned long *flags); ++ void (*driver_exit)(struct console *con, unsigned long flags); + atomic_t __private nbcon_state; + atomic_long_t __private nbcon_seq; + struct printk_buffers *pbufs; diff --git a/debian/patches-rt/0105-printk-Make-console_is_usable-available-to-nbcon.patch b/debian/patches-rt/0105-printk-Make-console_is_usable-available-to-nbcon.patch new file mode 100644 index 000000000..a0bf51492 --- /dev/null +++ b/debian/patches-rt/0105-printk-Make-console_is_usable-available-to-nbcon.patch @@ -0,0 +1,103 @@ +From: John Ogness +Date: Tue, 12 Sep 2023 13:25:41 +0000 +Subject: [PATCH 105/134] printk: Make console_is_usable() available to nbcon +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Move console_is_usable() as-is into internal.h so that it can +be used by nbcon printing functions as well. + +Signed-off-by: John Ogness +Reviewed-by: Petr Mladek +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/internal.h | 32 ++++++++++++++++++++++++++++++++ + kernel/printk/printk.c | 30 ------------------------------ + 2 files changed, 32 insertions(+), 30 deletions(-) + +--- a/kernel/printk/internal.h ++++ b/kernel/printk/internal.h +@@ -78,6 +78,36 @@ bool nbcon_alloc(struct console *con); + void nbcon_init(struct console *con); + void nbcon_free(struct console *con); + ++/* ++ * Check if the given console is currently capable and allowed to print ++ * records. ++ * ++ * Requires the console_srcu_read_lock. ++ */ ++static inline bool console_is_usable(struct console *con) ++{ ++ short flags = console_srcu_read_flags(con); ++ ++ if (!(flags & CON_ENABLED)) ++ return false; ++ ++ if ((flags & CON_SUSPENDED)) ++ return false; ++ ++ if (!con->write) ++ return false; ++ ++ /* ++ * Console drivers may assume that per-cpu resources have been ++ * allocated. So unless they're explicitly marked as being able to ++ * cope (CON_ANYTIME) don't call them until this CPU is officially up. ++ */ ++ if (!cpu_online(raw_smp_processor_id()) && !(flags & CON_ANYTIME)) ++ return false; ++ ++ return true; ++} ++ + #else + + #define PRINTK_PREFIX_MAX 0 +@@ -99,6 +129,8 @@ static inline bool nbcon_alloc(struct co + static inline void nbcon_init(struct console *con) { } + static inline void nbcon_free(struct console *con) { } + ++static inline bool console_is_usable(struct console *con) { return false; } ++ + #endif /* CONFIG_PRINTK */ + + extern struct printk_buffers printk_shared_pbufs; +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -2695,36 +2695,6 @@ int is_console_locked(void) + } + EXPORT_SYMBOL(is_console_locked); + +-/* +- * Check if the given console is currently capable and allowed to print +- * records. +- * +- * Requires the console_srcu_read_lock. +- */ +-static inline bool console_is_usable(struct console *con) +-{ +- short flags = console_srcu_read_flags(con); +- +- if (!(flags & CON_ENABLED)) +- return false; +- +- if ((flags & CON_SUSPENDED)) +- return false; +- +- if (!con->write) +- return false; +- +- /* +- * Console drivers may assume that per-cpu resources have been +- * allocated. So unless they're explicitly marked as being able to +- * cope (CON_ANYTIME) don't call them until this CPU is officially up. +- */ +- if (!cpu_online(raw_smp_processor_id()) && !(flags & CON_ANYTIME)) +- return false; +- +- return true; +-} +- + static void __console_unlock(void) + { + console_locked = 0; diff --git a/debian/patches-rt/0106-printk-Let-console_is_usable-handle-nbcon.patch b/debian/patches-rt/0106-printk-Let-console_is_usable-handle-nbcon.patch new file mode 100644 index 000000000..62a776cf2 --- /dev/null +++ b/debian/patches-rt/0106-printk-Let-console_is_usable-handle-nbcon.patch @@ -0,0 +1,43 @@ +From: John Ogness +Date: Tue, 12 Sep 2023 13:53:21 +0000 +Subject: [PATCH 106/134] printk: Let console_is_usable() handle nbcon +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +The nbcon consoles use a different printing callback. For nbcon +consoles, check for the write_atomic() callback instead of +write(). + +Signed-off-by: John Ogness +Reviewed-by: Petr Mladek +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/internal.h | 11 +++++++++-- + 1 file changed, 9 insertions(+), 2 deletions(-) + +--- a/kernel/printk/internal.h ++++ b/kernel/printk/internal.h +@@ -80,6 +80,8 @@ void nbcon_free(struct console *con); + + /* + * Check if the given console is currently capable and allowed to print ++ * records. Note that this function does not consider the current context, ++ * which can also play a role in deciding if @con can be used to print + * records. + * + * Requires the console_srcu_read_lock. +@@ -94,8 +96,13 @@ static inline bool console_is_usable(str + if ((flags & CON_SUSPENDED)) + return false; + +- if (!con->write) +- return false; ++ if (flags & CON_NBCON) { ++ if (!con->write_atomic) ++ return false; ++ } else { ++ if (!con->write) ++ return false; ++ } + + /* + * Console drivers may assume that per-cpu resources have been diff --git a/debian/patches-rt/0107-printk-Add-flags-argument-for-console_is_usable.patch b/debian/patches-rt/0107-printk-Add-flags-argument-for-console_is_usable.patch new file mode 100644 index 000000000..e8c4b4a73 --- /dev/null +++ b/debian/patches-rt/0107-printk-Add-flags-argument-for-console_is_usable.patch @@ -0,0 +1,67 @@ +From: John Ogness +Date: Tue, 12 Sep 2023 13:45:33 +0000 +Subject: [PATCH 107/134] printk: Add @flags argument for console_is_usable() +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +The caller of console_is_usable() usually needs @console->flags +for its own checks. Rather than having console_is_usable() read +its own copy, make the caller pass in the @flags. This also +ensures that the caller saw the same @flags value. + +Signed-off-by: John Ogness +Reviewed-by: Petr Mladek +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/internal.h | 8 ++------ + kernel/printk/printk.c | 5 +++-- + 2 files changed, 5 insertions(+), 8 deletions(-) + +--- a/kernel/printk/internal.h ++++ b/kernel/printk/internal.h +@@ -83,13 +83,9 @@ void nbcon_free(struct console *con); + * records. Note that this function does not consider the current context, + * which can also play a role in deciding if @con can be used to print + * records. +- * +- * Requires the console_srcu_read_lock. + */ +-static inline bool console_is_usable(struct console *con) ++static inline bool console_is_usable(struct console *con, short flags) + { +- short flags = console_srcu_read_flags(con); +- + if (!(flags & CON_ENABLED)) + return false; + +@@ -136,7 +132,7 @@ static inline bool nbcon_alloc(struct co + static inline void nbcon_init(struct console *con) { } + static inline void nbcon_free(struct console *con) { } + +-static inline bool console_is_usable(struct console *con) { return false; } ++static inline bool console_is_usable(struct console *con, short flags) { return false; } + + #endif /* CONFIG_PRINTK */ + +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -2940,9 +2940,10 @@ static bool console_flush_all(bool do_co + + cookie = console_srcu_read_lock(); + for_each_console_srcu(con) { ++ short flags = console_srcu_read_flags(con); + bool progress; + +- if (!console_is_usable(con)) ++ if (!console_is_usable(con, flags)) + continue; + any_usable = true; + +@@ -3784,7 +3785,7 @@ static bool __pr_flush(struct console *c + * that they make forward progress, so only increment + * @diff for usable consoles. + */ +- if (!console_is_usable(c)) ++ if (!console_is_usable(c, flags)) + continue; + + if (flags & CON_NBCON) { diff --git a/debian/patches-rt/0108-printk-nbcon-Provide-function-to-flush-using-write_a.patch b/debian/patches-rt/0108-printk-nbcon-Provide-function-to-flush-using-write_a.patch new file mode 100644 index 000000000..14933eef6 --- /dev/null +++ b/debian/patches-rt/0108-printk-nbcon-Provide-function-to-flush-using-write_a.patch @@ -0,0 +1,186 @@ +From: Thomas Gleixner +Date: Tue, 12 Sep 2023 12:00:08 +0000 +Subject: [PATCH 108/134] printk: nbcon: Provide function to flush using + write_atomic() +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Provide nbcon_atomic_flush_all() to perform flushing of all +registered nbcon consoles using their write_atomic() callback. +Like with legacy consoles, the nbcon consoles are flushed one +record per console. This allows all nbcon consoles to print +lines pseudo-simultaneously, rather than one console waiting +for the full ringbuffer to dump to another console before +printing anything. + +Unlike console_flush_all(), nbcon_atomic_flush_all() will only +flush up through the newest record at the time of the call. +This prevents a CPU from printing unbounded when other CPUs are +adding records. + +Perform nbcon console atomic flushing in +console_flush_on_panic(). This function is not only used in +panic() but also other locations where there may be stored +messages that need to be flushed. + +Co-developed-by: John Ogness +Signed-off-by: John Ogness +Signed-off-by: Thomas Gleixner (Intel) +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/internal.h | 2 + kernel/printk/nbcon.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++- + kernel/printk/printk.c | 2 + 3 files changed, 102 insertions(+), 2 deletions(-) + +--- a/kernel/printk/internal.h ++++ b/kernel/printk/internal.h +@@ -77,6 +77,7 @@ void nbcon_seq_force(struct console *con + bool nbcon_alloc(struct console *con); + void nbcon_init(struct console *con); + void nbcon_free(struct console *con); ++void nbcon_atomic_flush_all(void); + + /* + * Check if the given console is currently capable and allowed to print +@@ -131,6 +132,7 @@ static inline void nbcon_seq_force(struc + static inline bool nbcon_alloc(struct console *con) { return false; } + static inline void nbcon_init(struct console *con) { } + static inline void nbcon_free(struct console *con) { } ++static inline void nbcon_atomic_flush_all(void) { } + + static inline bool console_is_usable(struct console *con, short flags) { return false; } + +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -539,7 +539,6 @@ static struct printk_buffers panic_nbcon + * in an unsafe state. Otherwise, on success the caller may assume + * the console is not in an unsafe state. + */ +-__maybe_unused + static bool nbcon_context_try_acquire(struct nbcon_context *ctxt) + { + unsigned int cpu = smp_processor_id(); +@@ -841,7 +840,6 @@ EXPORT_SYMBOL_GPL(nbcon_exit_unsafe); + * When true is returned, @wctxt->ctxt.backlog indicates whether there are + * still records pending in the ringbuffer, + */ +-__maybe_unused + static bool nbcon_emit_next_record(struct nbcon_write_context *wctxt) + { + struct nbcon_context *ctxt = &ACCESS_PRIVATE(wctxt, ctxt); +@@ -931,6 +929,104 @@ static bool nbcon_emit_next_record(struc + } + + /** ++ * nbcon_atomic_emit_one - Print one record for an nbcon console using the ++ * write_atomic() callback ++ * @wctxt: An initialized write context struct to use ++ * for this context ++ * ++ * Return: False if the given console could not print a record or there ++ * are no more records to print, otherwise true. ++ * ++ * This is an internal helper to handle the locking of the console before ++ * calling nbcon_emit_next_record(). ++ */ ++static bool nbcon_atomic_emit_one(struct nbcon_write_context *wctxt) ++{ ++ struct nbcon_context *ctxt = &ACCESS_PRIVATE(wctxt, ctxt); ++ ++ if (!nbcon_context_try_acquire(ctxt)) ++ return false; ++ ++ /* ++ * nbcon_emit_next_record() returns false when the console was ++ * handed over or taken over. In both cases the context is no ++ * longer valid. ++ */ ++ if (!nbcon_emit_next_record(wctxt)) ++ return false; ++ ++ nbcon_context_release(ctxt); ++ ++ return ctxt->backlog; ++} ++ ++/** ++ * __nbcon_atomic_flush_all - Flush all nbcon consoles using their ++ * write_atomic() callback ++ * @stop_seq: Flush up until this record ++ */ ++static void __nbcon_atomic_flush_all(u64 stop_seq) ++{ ++ struct nbcon_write_context wctxt = { }; ++ struct nbcon_context *ctxt = &ACCESS_PRIVATE(&wctxt, ctxt); ++ struct console *con; ++ bool any_progress; ++ int cookie; ++ ++ do { ++ any_progress = false; ++ ++ cookie = console_srcu_read_lock(); ++ for_each_console_srcu(con) { ++ short flags = console_srcu_read_flags(con); ++ unsigned long irq_flags; ++ ++ if (!(flags & CON_NBCON)) ++ continue; ++ ++ if (!console_is_usable(con, flags)) ++ continue; ++ ++ if (nbcon_seq_read(con) >= stop_seq) ++ continue; ++ ++ memset(ctxt, 0, sizeof(*ctxt)); ++ ctxt->console = con; ++ ctxt->spinwait_max_us = 2000; ++ ctxt->prio = NBCON_PRIO_NORMAL; ++ ++ /* ++ * Atomic flushing does not use console driver ++ * synchronization (i.e. it does not hold the port ++ * lock for uart consoles). Therefore IRQs must be ++ * disabled to avoid being interrupted and then ++ * calling into a driver that will deadlock trying ++ * acquire console ownership. ++ */ ++ local_irq_save(irq_flags); ++ ++ any_progress |= nbcon_atomic_emit_one(&wctxt); ++ ++ local_irq_restore(irq_flags); ++ } ++ console_srcu_read_unlock(cookie); ++ } while (any_progress); ++} ++ ++/** ++ * nbcon_atomic_flush_all - Flush all nbcon consoles using their ++ * write_atomic() callback ++ * ++ * Flush the backlog up through the currently newest record. Any new ++ * records added while flushing will not be flushed. This is to avoid ++ * one CPU printing unbounded because other CPUs continue to add records. ++ */ ++void nbcon_atomic_flush_all(void) ++{ ++ __nbcon_atomic_flush_all(prb_next_reserve_seq(prb)); ++} ++ ++/** + * nbcon_alloc - Allocate buffers needed by the nbcon console + * @con: Console to allocate buffers for + * +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -3170,6 +3170,8 @@ void console_flush_on_panic(enum con_flu + console_srcu_read_unlock(cookie); + } + ++ nbcon_atomic_flush_all(); ++ + console_flush_all(false, &next_seq, &handover); + } + diff --git a/debian/patches-rt/0109-printk-Track-registered-boot-consoles.patch b/debian/patches-rt/0109-printk-Track-registered-boot-consoles.patch new file mode 100644 index 000000000..51b866f20 --- /dev/null +++ b/debian/patches-rt/0109-printk-Track-registered-boot-consoles.patch @@ -0,0 +1,78 @@ +From: John Ogness +Date: Tue, 24 Oct 2023 14:13:14 +0000 +Subject: [PATCH 109/134] printk: Track registered boot consoles +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Unfortunately it is not known if a boot console and a regular +(legacy or nbcon) console use the same hardware. For this reason +they must not be allowed to print simultaneously. + +For legacy consoles this is not an issue because they are +already synchronized with the boot consoles using the console +lock. However nbcon consoles can be triggered separately. + +Add a global flag @have_boot_console to identify if any boot +consoles are registered. This will be used in follow-up commits +to ensure that boot consoles and nbcon consoles cannot print +simultaneously. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/printk.c | 24 ++++++++++++++++++++++++ + 1 file changed, 24 insertions(+) + +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -463,6 +463,14 @@ static int console_msg_format = MSG_FORM + /* syslog_lock protects syslog_* variables and write access to clear_seq. */ + static DEFINE_MUTEX(syslog_lock); + ++/* ++ * Specifies if a boot console is registered. If boot consoles are present, ++ * nbcon consoles cannot print simultaneously and must be synchronized by ++ * the console lock. This is because boot consoles and nbcon consoles may ++ * have mapped the same hardware. ++ */ ++bool have_boot_console; ++ + #ifdef CONFIG_PRINTK + DECLARE_WAIT_QUEUE_HEAD(log_wait); + /* All 3 protected by @syslog_lock. */ +@@ -3500,6 +3508,9 @@ void register_console(struct console *ne + if (newcon->flags & CON_NBCON) + nbcon_init(newcon); + ++ if (newcon->flags & CON_BOOT) ++ have_boot_console = true; ++ + /* + * Put this console in the list - keep the + * preferred driver at the head of the list. +@@ -3552,6 +3563,8 @@ EXPORT_SYMBOL(register_console); + /* Must be called under console_list_lock(). */ + static int unregister_console_locked(struct console *console) + { ++ bool found_boot_con = false; ++ struct console *c; + int res; + + lockdep_assert_console_list_lock_held(); +@@ -3599,6 +3612,17 @@ static int unregister_console_locked(str + if (console->exit) + res = console->exit(console); + ++ /* ++ * With this console gone, the global flags tracking registered ++ * console types may have changed. Update them. ++ */ ++ for_each_console(c) { ++ if (c->flags & CON_BOOT) ++ found_boot_con = true; ++ } ++ if (!found_boot_con) ++ have_boot_console = false; ++ + return res; + } + diff --git a/debian/patches-rt/0110-printk-nbcon-Use-nbcon-consoles-in-console_flush_all.patch b/debian/patches-rt/0110-printk-nbcon-Use-nbcon-consoles-in-console_flush_all.patch new file mode 100644 index 000000000..b46ecd765 --- /dev/null +++ b/debian/patches-rt/0110-printk-nbcon-Use-nbcon-consoles-in-console_flush_all.patch @@ -0,0 +1,173 @@ +From: John Ogness +Date: Tue, 19 Sep 2023 14:33:27 +0000 +Subject: [PATCH 110/134] printk: nbcon: Use nbcon consoles in + console_flush_all() +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Allow nbcon consoles to print messages in the printk() caller +context by integrating them into console_flush_all(). The +write_atomic() callback is used for printing. + +Provide nbcon_console_emit_next_record(), which acts as the +nbcon variant of console_emit_next_record(). Call this variant +within console_flush_all() for nbcon consoles. Since nbcon +consoles use their own @nbcon_seq variable to track the next +record to print, this also must be appropriately handled. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/internal.h | 5 ++++ + kernel/printk/nbcon.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++ + kernel/printk/printk.c | 19 +++++++++++++---- + 3 files changed, 69 insertions(+), 5 deletions(-) + +--- a/kernel/printk/internal.h ++++ b/kernel/printk/internal.h +@@ -71,6 +71,8 @@ void defer_console_output(void); + + u16 printk_parse_prefix(const char *text, int *level, + enum printk_info_flags *flags); ++void console_lock_spinning_enable(void); ++int console_lock_spinning_disable_and_check(int cookie); + + u64 nbcon_seq_read(struct console *con); + void nbcon_seq_force(struct console *con, u64 seq); +@@ -78,6 +80,7 @@ bool nbcon_alloc(struct console *con); + void nbcon_init(struct console *con); + void nbcon_free(struct console *con); + void nbcon_atomic_flush_all(void); ++bool nbcon_atomic_emit_next_record(struct console *con, bool *handover, int cookie); + + /* + * Check if the given console is currently capable and allowed to print +@@ -133,6 +136,8 @@ static inline bool nbcon_alloc(struct co + static inline void nbcon_init(struct console *con) { } + static inline void nbcon_free(struct console *con) { } + static inline void nbcon_atomic_flush_all(void) { } ++static inline bool nbcon_atomic_emit_next_record(struct console *con, bool *handover, ++ int cookie) { return false; } + + static inline bool console_is_usable(struct console *con, short flags) { return false; } + +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -532,6 +532,7 @@ static struct printk_buffers panic_nbcon + * nbcon_context_try_acquire - Try to acquire nbcon console + * @ctxt: The context of the caller + * ++ * Context: Any context which could not be migrated to another CPU. + * Return: True if the console was acquired. False otherwise. + * + * If the caller allowed an unsafe hostile takeover, on success the +@@ -961,6 +962,55 @@ static bool nbcon_atomic_emit_one(struct + } + + /** ++ * nbcon_atomic_emit_next_record - Print one record for an nbcon console ++ * using the write_atomic() callback ++ * @con: The console to print on ++ * @handover: Will be set to true if a printk waiter has taken over the ++ * console_lock, in which case the caller is no longer holding ++ * both the console_lock and the SRCU read lock. Otherwise it ++ * is set to false. ++ * @cookie: The cookie from the SRCU read lock. ++ * ++ * Context: Any context which could not be migrated to another CPU. ++ * Return: True if a record could be printed, otherwise false. ++ * ++ * This function is meant to be called by console_flush_all() to print records ++ * on nbcon consoles using the write_atomic() callback. Essentially it is the ++ * nbcon version of console_emit_next_record(). ++ */ ++bool nbcon_atomic_emit_next_record(struct console *con, bool *handover, int cookie) ++{ ++ struct nbcon_write_context wctxt = { }; ++ struct nbcon_context *ctxt = &ACCESS_PRIVATE(&wctxt, ctxt); ++ unsigned long driver_flags; ++ bool progress = false; ++ unsigned long flags; ++ ++ *handover = false; ++ ++ /* Use the same locking order as console_emit_next_record(). */ ++ printk_safe_enter_irqsave(flags); ++ console_lock_spinning_enable(); ++ stop_critical_timings(); ++ ++ con->driver_enter(con, &driver_flags); ++ cant_migrate(); ++ ++ ctxt->console = con; ++ ctxt->prio = NBCON_PRIO_NORMAL; ++ ++ progress = nbcon_atomic_emit_one(&wctxt); ++ ++ con->driver_exit(con, driver_flags); ++ ++ start_critical_timings(); ++ *handover = console_lock_spinning_disable_and_check(cookie); ++ printk_safe_exit_irqrestore(flags); ++ ++ return progress; ++} ++ ++/** + * __nbcon_atomic_flush_all - Flush all nbcon consoles using their + * write_atomic() callback + * @stop_seq: Flush up until this record +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -1872,7 +1872,7 @@ static bool console_waiter; + * there may be a waiter spinning (like a spinlock). Also it must be + * ready to hand over the lock at the end of the section. + */ +-static void console_lock_spinning_enable(void) ++void console_lock_spinning_enable(void) + { + /* + * Do not use spinning in panic(). The panic CPU wants to keep the lock. +@@ -1911,7 +1911,7 @@ static void console_lock_spinning_enable + * + * Return: 1 if the lock rights were passed, 0 otherwise. + */ +-static int console_lock_spinning_disable_and_check(int cookie) ++int console_lock_spinning_disable_and_check(int cookie) + { + int waiter; + +@@ -2949,13 +2949,22 @@ static bool console_flush_all(bool do_co + cookie = console_srcu_read_lock(); + for_each_console_srcu(con) { + short flags = console_srcu_read_flags(con); ++ u64 printk_seq; + bool progress; + + if (!console_is_usable(con, flags)) + continue; + any_usable = true; + +- progress = console_emit_next_record(con, handover, cookie); ++ if (flags & CON_NBCON) { ++ progress = nbcon_atomic_emit_next_record(con, handover, cookie); ++ ++ printk_seq = nbcon_seq_read(con); ++ } else { ++ progress = console_emit_next_record(con, handover, cookie); ++ ++ printk_seq = con->seq; ++ } + + /* + * If a handover has occurred, the SRCU read lock +@@ -2965,8 +2974,8 @@ static bool console_flush_all(bool do_co + return false; + + /* Track the next of the highest seq flushed. */ +- if (con->seq > *next_seq) +- *next_seq = con->seq; ++ if (printk_seq > *next_seq) ++ *next_seq = printk_seq; + + if (!progress) + continue; diff --git a/debian/patches-rt/0111-printk-nbcon-Assign-priority-based-on-CPU-state.patch b/debian/patches-rt/0111-printk-nbcon-Assign-priority-based-on-CPU-state.patch new file mode 100644 index 000000000..7e826c3e4 --- /dev/null +++ b/debian/patches-rt/0111-printk-nbcon-Assign-priority-based-on-CPU-state.patch @@ -0,0 +1,113 @@ +From: John Ogness +Date: Thu, 14 Dec 2023 14:38:42 +0000 +Subject: [PATCH 111/134] printk: nbcon: Assign priority based on CPU state +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Use the current state of the CPU to determine which priority to +assign to the printing context. + +Note: The uart_port wrapper, which is responsible for non-console- + printing activities, will always use NORMAL priority. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/internal.h | 2 ++ + kernel/printk/nbcon.c | 30 ++++++++++++++++++++++++++++-- + 2 files changed, 30 insertions(+), 2 deletions(-) + +--- a/kernel/printk/internal.h ++++ b/kernel/printk/internal.h +@@ -79,6 +79,7 @@ void nbcon_seq_force(struct console *con + bool nbcon_alloc(struct console *con); + void nbcon_init(struct console *con); + void nbcon_free(struct console *con); ++enum nbcon_prio nbcon_get_default_prio(void); + void nbcon_atomic_flush_all(void); + bool nbcon_atomic_emit_next_record(struct console *con, bool *handover, int cookie); + +@@ -135,6 +136,7 @@ static inline void nbcon_seq_force(struc + static inline bool nbcon_alloc(struct console *con) { return false; } + static inline void nbcon_init(struct console *con) { } + static inline void nbcon_free(struct console *con) { } ++static inline enum nbcon_prio nbcon_get_default_prio(void) { return NBCON_PRIO_NONE; } + static inline void nbcon_atomic_flush_all(void) { } + static inline bool nbcon_atomic_emit_next_record(struct console *con, bool *handover, + int cookie) { return false; } +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -962,6 +962,22 @@ static bool nbcon_atomic_emit_one(struct + } + + /** ++ * nbcon_get_default_prio - The appropriate nbcon priority to use for nbcon ++ * printing on the current CPU ++ * ++ * Context: Any context which could not be migrated to another CPU. ++ * Return: The nbcon_prio to use for acquiring an nbcon console in this ++ * context for printing. ++ */ ++enum nbcon_prio nbcon_get_default_prio(void) ++{ ++ if (this_cpu_in_panic()) ++ return NBCON_PRIO_PANIC; ++ ++ return NBCON_PRIO_NORMAL; ++} ++ ++/** + * nbcon_atomic_emit_next_record - Print one record for an nbcon console + * using the write_atomic() callback + * @con: The console to print on +@@ -997,7 +1013,7 @@ bool nbcon_atomic_emit_next_record(struc + cant_migrate(); + + ctxt->console = con; +- ctxt->prio = NBCON_PRIO_NORMAL; ++ ctxt->prio = nbcon_get_default_prio(); + + progress = nbcon_atomic_emit_one(&wctxt); + +@@ -1043,7 +1059,6 @@ static void __nbcon_atomic_flush_all(u64 + memset(ctxt, 0, sizeof(*ctxt)); + ctxt->console = con; + ctxt->spinwait_max_us = 2000; +- ctxt->prio = NBCON_PRIO_NORMAL; + + /* + * Atomic flushing does not use console driver +@@ -1052,9 +1067,14 @@ static void __nbcon_atomic_flush_all(u64 + * disabled to avoid being interrupted and then + * calling into a driver that will deadlock trying + * acquire console ownership. ++ * ++ * This also disables migration in order to get the ++ * current CPU priority. + */ + local_irq_save(irq_flags); + ++ ctxt->prio = nbcon_get_default_prio(); ++ + any_progress |= nbcon_atomic_emit_one(&wctxt); + + local_irq_restore(irq_flags); +@@ -1166,6 +1186,9 @@ static inline bool uart_is_nbcon(struct + * + * If @up is an nbcon console, this console will be acquired and marked as + * unsafe. Otherwise this function does nothing. ++ * ++ * nbcon consoles acquired via the port lock wrapper always use priority ++ * NBCON_PRIO_NORMAL. + */ + void nbcon_acquire(struct uart_port *up) + { +@@ -1200,6 +1223,9 @@ EXPORT_SYMBOL_GPL(nbcon_acquire); + * + * If @up is an nbcon console, the console will be marked as safe and + * released. Otherwise this function does nothing. ++ * ++ * nbcon consoles acquired via the port lock wrapper always use priority ++ * NBCON_PRIO_NORMAL. + */ + void nbcon_release(struct uart_port *up) + { diff --git a/debian/patches-rt/0112-printk-nbcon-Add-unsafe-flushing-on-panic.patch b/debian/patches-rt/0112-printk-nbcon-Add-unsafe-flushing-on-panic.patch new file mode 100644 index 000000000..cc689de08 --- /dev/null +++ b/debian/patches-rt/0112-printk-nbcon-Add-unsafe-flushing-on-panic.patch @@ -0,0 +1,96 @@ +From: John Ogness +Date: Fri, 20 Oct 2023 10:03:42 +0000 +Subject: [PATCH 112/134] printk: nbcon: Add unsafe flushing on panic +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Add nbcon_atomic_flush_unsafe() to flush all nbcon consoles +using the write_atomic() callback and allowing unsafe hostile +takeovers. Call this at the end of panic() as a final attempt +to flush any pending messages. + +Note that legacy consoles use unsafe methods for flushing +from the beginning of panic (see bust_spinlocks()). Therefore, +systems using both legacy and nbcon consoles may still fail to +see panic messages due to unsafe legacy console usage. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/printk.h | 5 +++++ + kernel/panic.c | 1 + + kernel/printk/nbcon.c | 18 ++++++++++++++++-- + 3 files changed, 22 insertions(+), 2 deletions(-) + +--- a/include/linux/printk.h ++++ b/include/linux/printk.h +@@ -199,6 +199,7 @@ extern asmlinkage void dump_stack(void) + void printk_trigger_flush(void); + extern void nbcon_acquire(struct uart_port *up); + extern void nbcon_release(struct uart_port *up); ++void nbcon_atomic_flush_unsafe(void); + #else + static inline __printf(1, 0) + int vprintk(const char *s, va_list args) +@@ -287,6 +288,10 @@ static inline void nbcon_release(struct + { + } + ++static inline void nbcon_atomic_flush_unsafe(void) ++{ ++} ++ + #endif + + #ifdef CONFIG_SMP +--- a/kernel/panic.c ++++ b/kernel/panic.c +@@ -449,6 +449,7 @@ void panic(const char *fmt, ...) + * Explicitly flush the kernel log buffer one last time. + */ + console_flush_on_panic(CONSOLE_FLUSH_PENDING); ++ nbcon_atomic_flush_unsafe(); + + local_irq_enable(); + for (i = 0; ; i += PANIC_TIMER_STEP) { +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -1030,8 +1030,9 @@ bool nbcon_atomic_emit_next_record(struc + * __nbcon_atomic_flush_all - Flush all nbcon consoles using their + * write_atomic() callback + * @stop_seq: Flush up until this record ++ * @allow_unsafe_takeover: True, to allow unsafe hostile takeovers + */ +-static void __nbcon_atomic_flush_all(u64 stop_seq) ++static void __nbcon_atomic_flush_all(u64 stop_seq, bool allow_unsafe_takeover) + { + struct nbcon_write_context wctxt = { }; + struct nbcon_context *ctxt = &ACCESS_PRIVATE(&wctxt, ctxt); +@@ -1059,6 +1060,7 @@ static void __nbcon_atomic_flush_all(u64 + memset(ctxt, 0, sizeof(*ctxt)); + ctxt->console = con; + ctxt->spinwait_max_us = 2000; ++ ctxt->allow_unsafe_takeover = allow_unsafe_takeover; + + /* + * Atomic flushing does not use console driver +@@ -1093,7 +1095,19 @@ static void __nbcon_atomic_flush_all(u64 + */ + void nbcon_atomic_flush_all(void) + { +- __nbcon_atomic_flush_all(prb_next_reserve_seq(prb)); ++ __nbcon_atomic_flush_all(prb_next_reserve_seq(prb), false); ++} ++ ++/** ++ * nbcon_atomic_flush_unsafe - Flush all nbcon consoles using their ++ * write_atomic() callback and allowing unsafe hostile takeovers ++ * ++ * Flush the backlog up through the currently newest record. Unsafe hostile ++ * takeovers will be performed, if necessary. ++ */ ++void nbcon_atomic_flush_unsafe(void) ++{ ++ __nbcon_atomic_flush_all(prb_next_reserve_seq(prb), true); + } + + /** diff --git a/debian/patches-rt/0113-printk-Avoid-console_lock-dance-if-no-legacy-or-boot.patch b/debian/patches-rt/0113-printk-Avoid-console_lock-dance-if-no-legacy-or-boot.patch new file mode 100644 index 000000000..a73363867 --- /dev/null +++ b/debian/patches-rt/0113-printk-Avoid-console_lock-dance-if-no-legacy-or-boot.patch @@ -0,0 +1,211 @@ +From: John Ogness +Date: Tue, 26 Sep 2023 12:44:07 +0000 +Subject: [PATCH 113/134] printk: Avoid console_lock dance if no legacy or boot + consoles +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Currently the console lock is used to attempt legacy-type +printing even if there are no legacy or boot consoles registered. +If no such consoles are registered, the console lock does not +need to be taken. + +Also, if boot consoles are registered, nbcon consoles must +perform their atomic printing under the console lock in order +to be synchronized with boot consoles. + +Add tracking of legacy console registration and use it with +boot console tracking to avoid unnecessary code paths, i.e. +do not use the console lock if there are no boot consoles +and no legacy consoles. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/internal.h | 12 +++++++++ + kernel/printk/printk.c | 59 +++++++++++++++++++++++++++++++++++------------ + 2 files changed, 56 insertions(+), 15 deletions(-) + +--- a/kernel/printk/internal.h ++++ b/kernel/printk/internal.h +@@ -44,6 +44,16 @@ enum printk_info_flags { + }; + + extern struct printk_ringbuffer *prb; ++extern bool have_legacy_console; ++extern bool have_boot_console; ++ ++/* ++ * Specifies if the console lock/unlock dance is needed for console ++ * printing. If @have_boot_console is true, the nbcon consoles will ++ * be printed serially along with the legacy consoles because nbcon ++ * consoles cannot print simultaneously with boot consoles. ++ */ ++#define printing_via_unlock (have_legacy_console || have_boot_console) + + __printf(4, 0) + int vprintk_store(int facility, int level, +@@ -122,6 +132,8 @@ static inline bool console_is_usable(str + #define PRINTK_MESSAGE_MAX 0 + #define PRINTKRB_RECORD_MAX 0 + ++#define printing_via_unlock (false) ++ + /* + * In !PRINTK builds we still export console_sem + * semaphore and some of console functions (console_unlock()/etc.), so +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -464,6 +464,13 @@ static int console_msg_format = MSG_FORM + static DEFINE_MUTEX(syslog_lock); + + /* ++ * Specifies if a legacy console is registered. If legacy consoles are ++ * present, it is necessary to perform the console_lock/console_unlock dance ++ * whenever console flushing should occur. ++ */ ++bool have_legacy_console; ++ ++/* + * Specifies if a boot console is registered. If boot consoles are present, + * nbcon consoles cannot print simultaneously and must be synchronized by + * the console lock. This is because boot consoles and nbcon consoles may +@@ -2345,7 +2352,7 @@ asmlinkage int vprintk_emit(int facility + printed_len = vprintk_store(facility, level, dev_info, fmt, args); + + /* If called from the scheduler, we can not call up(). */ +- if (!in_sched) { ++ if (!in_sched && printing_via_unlock) { + /* + * The caller may be holding system-critical or + * timing-sensitive locks. Disable preemption during +@@ -2646,7 +2653,7 @@ void resume_console(void) + */ + static int console_cpu_notify(unsigned int cpu) + { +- if (!cpuhp_tasks_frozen) { ++ if (!cpuhp_tasks_frozen && printing_via_unlock) { + /* If trylock fails, someone else is doing the printing */ + if (console_trylock()) + console_unlock(); +@@ -3189,7 +3196,8 @@ void console_flush_on_panic(enum con_flu + + nbcon_atomic_flush_all(); + +- console_flush_all(false, &next_seq, &handover); ++ if (printing_via_unlock) ++ console_flush_all(false, &next_seq, &handover); + } + + /* +@@ -3514,8 +3522,11 @@ void register_console(struct console *ne + newcon->dropped = 0; + console_init_seq(newcon, bootcon_registered); + +- if (newcon->flags & CON_NBCON) ++ if (newcon->flags & CON_NBCON) { + nbcon_init(newcon); ++ } else { ++ have_legacy_console = true; ++ } + + if (newcon->flags & CON_BOOT) + have_boot_console = true; +@@ -3572,6 +3583,7 @@ EXPORT_SYMBOL(register_console); + /* Must be called under console_list_lock(). */ + static int unregister_console_locked(struct console *console) + { ++ bool found_legacy_con = false; + bool found_boot_con = false; + struct console *c; + int res; +@@ -3628,9 +3640,13 @@ static int unregister_console_locked(str + for_each_console(c) { + if (c->flags & CON_BOOT) + found_boot_con = true; ++ if (!(c->flags & CON_NBCON)) ++ found_legacy_con = true; + } + if (!found_boot_con) + have_boot_console = false; ++ if (!found_legacy_con) ++ have_legacy_console = false; + + return res; + } +@@ -3782,6 +3798,7 @@ static bool __pr_flush(struct console *c + u64 last_diff = 0; + u64 printk_seq; + short flags; ++ bool locked; + int cookie; + u64 diff; + u64 seq; +@@ -3791,22 +3808,28 @@ static bool __pr_flush(struct console *c + seq = prb_next_reserve_seq(prb); + + /* Flush the consoles so that records up to @seq are printed. */ +- console_lock(); +- console_unlock(); ++ if (printing_via_unlock) { ++ console_lock(); ++ console_unlock(); ++ } + + for (;;) { + unsigned long begin_jiffies; + unsigned long slept_jiffies; + ++ locked = false; + diff = 0; + +- /* +- * Hold the console_lock to guarantee safe access to +- * console->seq. Releasing console_lock flushes more +- * records in case @seq is still not printed on all +- * usable consoles. +- */ +- console_lock(); ++ if (printing_via_unlock) { ++ /* ++ * Hold the console_lock to guarantee safe access to ++ * console->seq. Releasing console_lock flushes more ++ * records in case @seq is still not printed on all ++ * usable consoles. ++ */ ++ console_lock(); ++ locked = true; ++ } + + cookie = console_srcu_read_lock(); + for_each_console_srcu(c) { +@@ -3826,6 +3849,7 @@ static bool __pr_flush(struct console *c + if (flags & CON_NBCON) { + printk_seq = nbcon_seq_read(c); + } else { ++ WARN_ON_ONCE(!locked); + printk_seq = c->seq; + } + +@@ -3837,7 +3861,8 @@ static bool __pr_flush(struct console *c + if (diff != last_diff && reset_on_progress) + remaining_jiffies = timeout_jiffies; + +- console_unlock(); ++ if (locked) ++ console_unlock(); + + /* Note: @diff is 0 if there are no usable consoles. */ + if (diff == 0 || remaining_jiffies == 0) +@@ -3959,7 +3984,11 @@ void defer_console_output(void) + * New messages may have been added directly to the ringbuffer + * using vprintk_store(), so wake any waiters as well. + */ +- __wake_up_klogd(PRINTK_PENDING_WAKEUP | PRINTK_PENDING_OUTPUT); ++ int val = PRINTK_PENDING_WAKEUP; ++ ++ if (printing_via_unlock) ++ val |= PRINTK_PENDING_OUTPUT; ++ __wake_up_klogd(val); + } + + void printk_trigger_flush(void) diff --git a/debian/patches-rt/0114-printk-Track-nbcon-consoles.patch b/debian/patches-rt/0114-printk-Track-nbcon-consoles.patch new file mode 100644 index 000000000..fb85c5bbb --- /dev/null +++ b/debian/patches-rt/0114-printk-Track-nbcon-consoles.patch @@ -0,0 +1,67 @@ +From: John Ogness +Date: Mon, 11 Dec 2023 09:36:52 +0000 +Subject: [PATCH 114/134] printk: Track nbcon consoles +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Add a global flag @have_nbcon_console to identify if any nbcon +consoles are registered. This will be used in follow-up commits +to preserve legacy behavior when no nbcon consoles are registered. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/printk.c | 16 +++++++++++++++- + 1 file changed, 15 insertions(+), 1 deletion(-) + +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -471,6 +471,13 @@ static DEFINE_MUTEX(syslog_lock); + bool have_legacy_console; + + /* ++ * Specifies if an nbcon console is registered. If nbcon consoles are present, ++ * synchronous printing of legacy consoles will not occur during panic until ++ * the backtrace has been stored to the ringbuffer. ++ */ ++bool have_nbcon_console; ++ ++/* + * Specifies if a boot console is registered. If boot consoles are present, + * nbcon consoles cannot print simultaneously and must be synchronized by + * the console lock. This is because boot consoles and nbcon consoles may +@@ -3523,6 +3530,7 @@ void register_console(struct console *ne + console_init_seq(newcon, bootcon_registered); + + if (newcon->flags & CON_NBCON) { ++ have_nbcon_console = true; + nbcon_init(newcon); + } else { + have_legacy_console = true; +@@ -3584,6 +3592,7 @@ EXPORT_SYMBOL(register_console); + static int unregister_console_locked(struct console *console) + { + bool found_legacy_con = false; ++ bool found_nbcon_con = false; + bool found_boot_con = false; + struct console *c; + int res; +@@ -3640,13 +3649,18 @@ static int unregister_console_locked(str + for_each_console(c) { + if (c->flags & CON_BOOT) + found_boot_con = true; +- if (!(c->flags & CON_NBCON)) ++ ++ if (c->flags & CON_NBCON) ++ found_nbcon_con = true; ++ else + found_legacy_con = true; + } + if (!found_boot_con) + have_boot_console = false; + if (!found_legacy_con) + have_legacy_console = false; ++ if (!found_nbcon_con) ++ have_nbcon_console = false; + + return res; + } diff --git a/debian/patches-rt/0115-printk-Coordinate-direct-printing-in-panic.patch b/debian/patches-rt/0115-printk-Coordinate-direct-printing-in-panic.patch new file mode 100644 index 000000000..972df7668 --- /dev/null +++ b/debian/patches-rt/0115-printk-Coordinate-direct-printing-in-panic.patch @@ -0,0 +1,134 @@ +From: John Ogness +Date: Wed, 22 Nov 2023 11:56:58 +0000 +Subject: [PATCH 115/134] printk: Coordinate direct printing in panic +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Perform printing by nbcon consoles on the panic CPU from the +printk() caller context in order to get panic messages printed +as soon as possible. + +If legacy and nbcon consoles are registered, the legacy consoles +will no longer perform direct printing on the panic CPU until +after the backtrace has been stored. This will give the safe +nbcon consoles a chance to print the panic messages before +allowing the unsafe legacy consoles to print. + +If no nbcon consoles are registered, there is no change in +behavior (i.e. legacy consoles will always attempt to print +from the printk() caller context). + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/printk.h | 2 + + kernel/panic.c | 2 + + kernel/printk/printk.c | 53 ++++++++++++++++++++++++++++++++++++++++++------- + 3 files changed, 50 insertions(+), 7 deletions(-) + +--- a/include/linux/printk.h ++++ b/include/linux/printk.h +@@ -782,3 +782,5 @@ static inline void print_hex_dump_debug( + print_hex_dump_debug(prefix_str, prefix_type, 16, 1, buf, len, true) + + #endif ++ ++void printk_legacy_allow_panic_sync(void); +--- a/kernel/panic.c ++++ b/kernel/panic.c +@@ -366,6 +366,8 @@ void panic(const char *fmt, ...) + */ + atomic_notifier_call_chain(&panic_notifier_list, 0, buf); + ++ printk_legacy_allow_panic_sync(); ++ + panic_print_sys_info(false); + + kmsg_dump(KMSG_DUMP_PANIC); +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -2330,12 +2330,23 @@ int vprintk_store(int facility, int leve + return ret; + } + ++static bool legacy_allow_panic_sync; ++ ++/* ++ * This acts as a one-way switch to allow legacy consoles to print from ++ * the printk() caller context on a panic CPU. ++ */ ++void printk_legacy_allow_panic_sync(void) ++{ ++ legacy_allow_panic_sync = true; ++} ++ + asmlinkage int vprintk_emit(int facility, int level, + const struct dev_printk_info *dev_info, + const char *fmt, va_list args) + { ++ bool do_trylock_unlock = printing_via_unlock; + int printed_len; +- bool in_sched = false; + + /* Suppress unimportant messages after panic happens */ + if (unlikely(suppress_printk)) +@@ -2351,15 +2362,43 @@ asmlinkage int vprintk_emit(int facility + + if (level == LOGLEVEL_SCHED) { + level = LOGLEVEL_DEFAULT; +- in_sched = true; ++ /* If called from the scheduler, we can not call up(). */ ++ do_trylock_unlock = false; + } + + printk_delay(level); + + printed_len = vprintk_store(facility, level, dev_info, fmt, args); + +- /* If called from the scheduler, we can not call up(). */ +- if (!in_sched && printing_via_unlock) { ++ if (!have_boot_console && have_nbcon_console) { ++ bool is_panic_context = this_cpu_in_panic(); ++ ++ /* ++ * In panic, the legacy consoles are not allowed to print from ++ * the printk calling context unless explicitly allowed. This ++ * gives the safe nbcon consoles a chance to print out all the ++ * panic messages first. This restriction only applies if ++ * there are nbcon consoles registered. ++ */ ++ if (is_panic_context) ++ do_trylock_unlock &= legacy_allow_panic_sync; ++ ++ /* ++ * There are situations where nbcon atomic printing should ++ * happen in the printk() caller context: ++ * ++ * - When this CPU is in panic. ++ * ++ * Note that if boot consoles are registered, the ++ * console_lock/console_unlock dance must be relied upon ++ * instead because nbcon consoles cannot print simultaneously ++ * with boot consoles. ++ */ ++ if (is_panic_context) ++ nbcon_atomic_flush_all(); ++ } ++ ++ if (do_trylock_unlock) { + /* + * The caller may be holding system-critical or + * timing-sensitive locks. Disable preemption during +@@ -2379,10 +2418,10 @@ asmlinkage int vprintk_emit(int facility + preempt_enable(); + } + +- if (in_sched) +- defer_console_output(); +- else ++ if (do_trylock_unlock) + wake_up_klogd(); ++ else ++ defer_console_output(); + + return printed_len; + } diff --git a/debian/patches-rt/0116-printk-nbcon-Implement-emergency-sections.patch b/debian/patches-rt/0116-printk-nbcon-Implement-emergency-sections.patch new file mode 100644 index 000000000..11175cacb --- /dev/null +++ b/debian/patches-rt/0116-printk-nbcon-Implement-emergency-sections.patch @@ -0,0 +1,232 @@ +From: Thomas Gleixner +Date: Mon, 11 Sep 2023 15:21:57 +0000 +Subject: [PATCH 116/134] printk: nbcon: Implement emergency sections +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +In emergency situations (something has gone wrong but the +system continues to operate), usually important information +(such as a backtrace) is generated via printk(). Each +individual printk record has little meaning. It is the +collection of printk messages that is most often needed by +developers and users. + +In order to help ensure that the collection of printk messages +in an emergency situation are all stored to the ringbuffer as +quickly as possible, disable console output for that CPU while +it is in the emergency situation. When exiting the emergency +situation, trigger the consoles to be flushed. + +Add per-CPU emergency nesting tracking because an emergency +can arise while in an emergency situation. + +Add functions to mark the beginning and end of emergency +sections where the urgent messages are generated. + +Do not print if the current CPU is in an emergency state. + +Trigger console flushing when exiting all emergency nesting. + +Note that the emergency state is not system-wide. While one CPU +is in an emergency state, another CPU may continue to print +console messages. + +Co-developed-by: John Ogness +Signed-off-by: John Ogness +Signed-off-by: Thomas Gleixner (Intel) +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/console.h | 4 ++ + include/linux/printk.h | 7 ++-- + kernel/printk/nbcon.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++ + kernel/printk/printk.c | 25 +++++++++++--- + 4 files changed, 109 insertions(+), 8 deletions(-) + +--- a/include/linux/console.h ++++ b/include/linux/console.h +@@ -458,10 +458,14 @@ static inline bool console_is_registered + hlist_for_each_entry(con, &console_list, node) + + #ifdef CONFIG_PRINTK ++extern void nbcon_cpu_emergency_enter(void); ++extern void nbcon_cpu_emergency_exit(void); + extern bool nbcon_can_proceed(struct nbcon_write_context *wctxt); + extern bool nbcon_enter_unsafe(struct nbcon_write_context *wctxt); + extern bool nbcon_exit_unsafe(struct nbcon_write_context *wctxt); + #else ++static inline void nbcon_cpu_emergency_enter(void) { } ++static inline void nbcon_cpu_emergency_exit(void) { } + static inline bool nbcon_can_proceed(struct nbcon_write_context *wctxt) { return false; } + static inline bool nbcon_enter_unsafe(struct nbcon_write_context *wctxt) { return false; } + static inline bool nbcon_exit_unsafe(struct nbcon_write_context *wctxt) { return false; } +--- a/include/linux/printk.h ++++ b/include/linux/printk.h +@@ -197,6 +197,7 @@ void show_regs_print_info(const char *lo + extern asmlinkage void dump_stack_lvl(const char *log_lvl) __cold; + extern asmlinkage void dump_stack(void) __cold; + void printk_trigger_flush(void); ++void printk_legacy_allow_panic_sync(void); + extern void nbcon_acquire(struct uart_port *up); + extern void nbcon_release(struct uart_port *up); + void nbcon_atomic_flush_unsafe(void); +@@ -280,6 +281,10 @@ static inline void printk_trigger_flush( + { + } + ++static inline void printk_legacy_allow_panic_sync(void) ++{ ++} ++ + static inline void nbcon_acquire(struct uart_port *up) + { + } +@@ -782,5 +787,3 @@ static inline void print_hex_dump_debug( + print_hex_dump_debug(prefix_str, prefix_type, 16, 1, buf, len, true) + + #endif +- +-void printk_legacy_allow_panic_sync(void); +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -929,6 +929,29 @@ static bool nbcon_emit_next_record(struc + return nbcon_context_exit_unsafe(ctxt); + } + ++/* Track the nbcon emergency nesting per CPU. */ ++static DEFINE_PER_CPU(unsigned int, nbcon_pcpu_emergency_nesting); ++static unsigned int early_nbcon_pcpu_emergency_nesting __initdata; ++ ++/** ++ * nbcon_get_cpu_emergency_nesting - Get the per CPU emergency nesting pointer ++ * ++ * Return: Either a pointer to the per CPU emergency nesting counter of ++ * the current CPU or to the init data during early boot. ++ */ ++static __ref unsigned int *nbcon_get_cpu_emergency_nesting(void) ++{ ++ /* ++ * The value of __printk_percpu_data_ready gets set in normal ++ * context and before SMP initialization. As a result it could ++ * never change while inside an nbcon emergency section. ++ */ ++ if (!printk_percpu_data_ready()) ++ return &early_nbcon_pcpu_emergency_nesting; ++ ++ return this_cpu_ptr(&nbcon_pcpu_emergency_nesting); ++} ++ + /** + * nbcon_atomic_emit_one - Print one record for an nbcon console using the + * write_atomic() callback +@@ -971,9 +994,15 @@ static bool nbcon_atomic_emit_one(struct + */ + enum nbcon_prio nbcon_get_default_prio(void) + { ++ unsigned int *cpu_emergency_nesting; ++ + if (this_cpu_in_panic()) + return NBCON_PRIO_PANIC; + ++ cpu_emergency_nesting = nbcon_get_cpu_emergency_nesting(); ++ if (*cpu_emergency_nesting) ++ return NBCON_PRIO_EMERGENCY; ++ + return NBCON_PRIO_NORMAL; + } + +@@ -1111,6 +1140,58 @@ void nbcon_atomic_flush_unsafe(void) + } + + /** ++ * nbcon_cpu_emergency_enter - Enter an emergency section where printk() ++ * messages for that CPU are only stored ++ * ++ * Upon exiting the emergency section, all stored messages are flushed. ++ * ++ * Context: Any context. Disables preemption. ++ * ++ * When within an emergency section, no printing occurs on that CPU. This ++ * is to allow all emergency messages to be dumped into the ringbuffer before ++ * flushing the ringbuffer. The actual printing occurs when exiting the ++ * outermost emergency section. ++ */ ++void nbcon_cpu_emergency_enter(void) ++{ ++ unsigned int *cpu_emergency_nesting; ++ ++ preempt_disable(); ++ ++ cpu_emergency_nesting = nbcon_get_cpu_emergency_nesting(); ++ (*cpu_emergency_nesting)++; ++} ++ ++/** ++ * nbcon_cpu_emergency_exit - Exit an emergency section and flush the ++ * stored messages ++ * ++ * Flushing only occurs when exiting all nesting for the CPU. ++ * ++ * Context: Any context. Enables preemption. ++ */ ++void nbcon_cpu_emergency_exit(void) ++{ ++ unsigned int *cpu_emergency_nesting; ++ bool do_trigger_flush = false; ++ ++ cpu_emergency_nesting = nbcon_get_cpu_emergency_nesting(); ++ ++ WARN_ON_ONCE(*cpu_emergency_nesting == 0); ++ ++ if (*cpu_emergency_nesting == 1) ++ do_trigger_flush = true; ++ ++ /* Undo the nesting count of nbcon_cpu_emergency_enter(). */ ++ (*cpu_emergency_nesting)--; ++ ++ preempt_enable(); ++ ++ if (do_trigger_flush) ++ printk_trigger_flush(); ++} ++ ++/** + * nbcon_alloc - Allocate buffers needed by the nbcon console + * @con: Console to allocate buffers for + * +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -2405,16 +2405,29 @@ asmlinkage int vprintk_emit(int facility + * printing of all remaining records to all consoles so that + * this context can return as soon as possible. Hopefully + * another printk() caller will take over the printing. ++ * ++ * Also, nbcon_get_default_prio() requires migration disabled. + */ + preempt_disable(); ++ + /* +- * Try to acquire and then immediately release the console +- * semaphore. The release will print out buffers. With the +- * spinning variant, this context tries to take over the +- * printing from another printing context. ++ * Do not emit for EMERGENCY priority. The console will be ++ * explicitly flushed when exiting the emergency section. + */ +- if (console_trylock_spinning()) +- console_unlock(); ++ if (nbcon_get_default_prio() == NBCON_PRIO_EMERGENCY) { ++ do_trylock_unlock = false; ++ } else { ++ /* ++ * Try to acquire and then immediately release the ++ * console semaphore. The release will print out ++ * buffers. With the spinning variant, this context ++ * tries to take over the printing from another ++ * printing context. ++ */ ++ if (console_trylock_spinning()) ++ console_unlock(); ++ } ++ + preempt_enable(); + } + diff --git a/debian/patches-rt/0117-panic-Mark-emergency-section-in-warn.patch b/debian/patches-rt/0117-panic-Mark-emergency-section-in-warn.patch new file mode 100644 index 000000000..84201d25f --- /dev/null +++ b/debian/patches-rt/0117-panic-Mark-emergency-section-in-warn.patch @@ -0,0 +1,38 @@ +From: Thomas Gleixner +Date: Mon, 11 Sep 2023 15:53:04 +0000 +Subject: [PATCH 117/134] panic: Mark emergency section in warn +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Mark the full contents of __warn() as an emergency section. In +this section, the CPU will not perform console output for the +printk() calls. Instead, a flushing of the console output will +triggered when exiting the emergency section. + +Co-developed-by: John Ogness +Signed-off-by: John Ogness +Signed-off-by: Thomas Gleixner (Intel) +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/panic.c | 4 ++++ + 1 file changed, 4 insertions(+) + +--- a/kernel/panic.c ++++ b/kernel/panic.c +@@ -663,6 +663,8 @@ struct warn_args { + void __warn(const char *file, int line, void *caller, unsigned taint, + struct pt_regs *regs, struct warn_args *args) + { ++ nbcon_cpu_emergency_enter(); ++ + disable_trace_on_warning(); + + if (file) +@@ -693,6 +695,8 @@ void __warn(const char *file, int line, + + /* Just a warning, don't kill lockdep. */ + add_taint(taint, LOCKDEP_STILL_OK); ++ ++ nbcon_cpu_emergency_exit(); + } + + #ifdef CONFIG_BUG diff --git a/debian/patches-rt/0118-panic-Mark-emergency-section-in-oops.patch b/debian/patches-rt/0118-panic-Mark-emergency-section-in-oops.patch new file mode 100644 index 000000000..6e52fd3a6 --- /dev/null +++ b/debian/patches-rt/0118-panic-Mark-emergency-section-in-oops.patch @@ -0,0 +1,39 @@ +From: John Ogness +Date: Tue, 19 Sep 2023 17:07:34 +0000 +Subject: [PATCH 118/134] panic: Mark emergency section in oops +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Mark an emergency section beginning with oops_enter() until the +end of oops_exit(). In this section, the CPU will not perform +console output for the printk() calls. Instead, a flushing of the +console output will triggered when exiting the emergency section. + +The very end of oops_exit() performs a kmsg_dump(). This is not +included in the emergency section because it is another +flushing mechanism that should occur after the consoles have +been triggered to flush. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/panic.c | 2 ++ + 1 file changed, 2 insertions(+) + +--- a/kernel/panic.c ++++ b/kernel/panic.c +@@ -630,6 +630,7 @@ bool oops_may_print(void) + */ + void oops_enter(void) + { ++ nbcon_cpu_emergency_enter(); + tracing_off(); + /* can't trust the integrity of the kernel anymore: */ + debug_locks_off(); +@@ -652,6 +653,7 @@ void oops_exit(void) + { + do_oops_enter_exit(); + print_oops_end_marker(); ++ nbcon_cpu_emergency_exit(); + kmsg_dump(KMSG_DUMP_OOPS); + } + diff --git a/debian/patches-rt/0119-rcu-Mark-emergency-section-in-rcu-stalls.patch b/debian/patches-rt/0119-rcu-Mark-emergency-section-in-rcu-stalls.patch new file mode 100644 index 000000000..d1d6efced --- /dev/null +++ b/debian/patches-rt/0119-rcu-Mark-emergency-section-in-rcu-stalls.patch @@ -0,0 +1,45 @@ +From: John Ogness +Date: Mon, 11 Sep 2023 15:53:39 +0000 +Subject: [PATCH 119/134] rcu: Mark emergency section in rcu stalls +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Mark an emergency section within print_other_cpu_stall(), where +RCU stall information is printed. In this section, the CPU will +not perform console output for the printk() calls. Instead, a +flushing of the console output will triggered when exiting the +emergency section. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/rcu/tree_stall.h | 5 +++++ + 1 file changed, 5 insertions(+) + +--- a/kernel/rcu/tree_stall.h ++++ b/kernel/rcu/tree_stall.h +@@ -8,6 +8,7 @@ + */ + + #include ++#include + + ////////////////////////////////////////////////////////////////////////////// + // +@@ -603,6 +604,8 @@ static void print_other_cpu_stall(unsign + if (rcu_stall_is_suppressed()) + return; + ++ nbcon_cpu_emergency_enter(); ++ + /* + * OK, time to rat on our buddy... + * See Documentation/RCU/stallwarn.rst for info on how to debug +@@ -657,6 +660,8 @@ static void print_other_cpu_stall(unsign + panic_on_rcu_stall(); + + rcu_force_quiescent_state(); /* Kick them all. */ ++ ++ nbcon_cpu_emergency_exit(); + } + + static void print_cpu_stall(unsigned long gps) diff --git a/debian/patches-rt/0120-lockdep-Mark-emergency-section-in-lockdep-splats.patch b/debian/patches-rt/0120-lockdep-Mark-emergency-section-in-lockdep-splats.patch new file mode 100644 index 000000000..248d17afc --- /dev/null +++ b/debian/patches-rt/0120-lockdep-Mark-emergency-section-in-lockdep-splats.patch @@ -0,0 +1,45 @@ +From: John Ogness +Date: Mon, 18 Sep 2023 20:27:41 +0000 +Subject: [PATCH 120/134] lockdep: Mark emergency section in lockdep splats +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Mark an emergency section within print_usage_bug(), where +lockdep bugs are printed. In this section, the CPU will not +perform console output for the printk() calls. Instead, a +flushing of the console output will triggered when exiting +the emergency section. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/locking/lockdep.c | 5 +++++ + 1 file changed, 5 insertions(+) + +--- a/kernel/locking/lockdep.c ++++ b/kernel/locking/lockdep.c +@@ -56,6 +56,7 @@ + #include + #include + #include ++#include + + #include + +@@ -3971,6 +3972,8 @@ print_usage_bug(struct task_struct *curr + if (!debug_locks_off() || debug_locks_silent) + return; + ++ nbcon_cpu_emergency_enter(); ++ + pr_warn("\n"); + pr_warn("================================\n"); + pr_warn("WARNING: inconsistent lock state\n"); +@@ -3999,6 +4002,8 @@ print_usage_bug(struct task_struct *curr + + pr_warn("\nstack backtrace:\n"); + dump_stack(); ++ ++ nbcon_cpu_emergency_exit(); + } + + /* diff --git a/debian/patches-rt/0121-printk-nbcon-Introduce-printing-kthreads.patch b/debian/patches-rt/0121-printk-nbcon-Introduce-printing-kthreads.patch new file mode 100644 index 000000000..7b158ddb7 --- /dev/null +++ b/debian/patches-rt/0121-printk-nbcon-Introduce-printing-kthreads.patch @@ -0,0 +1,441 @@ +From: Thomas Gleixner +Date: Fri, 22 Sep 2023 14:12:21 +0000 +Subject: [PATCH 121/134] printk: nbcon: Introduce printing kthreads +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Provide the main implementation for running a printer kthread +per nbcon console that is takeover/handover aware. + +The main print function nbcon_emit_next_record() will generate +a warning if a task other than the dedicated printer thread +tries to print using write_thread(). + +Co-developed-by: John Ogness +Signed-off-by: John Ogness +Signed-off-by: Thomas Gleixner (Intel) +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/console.h | 8 ++ + kernel/printk/internal.h | 25 ++++++ + kernel/printk/nbcon.c | 188 ++++++++++++++++++++++++++++++++++++++++++++++- + kernel/printk/printk.c | 31 +++++++ + 4 files changed, 249 insertions(+), 3 deletions(-) + +--- a/include/linux/console.h ++++ b/include/linux/console.h +@@ -17,6 +17,7 @@ + #include + #include + #include ++#include + #include + + struct vc_data; +@@ -296,12 +297,15 @@ struct nbcon_write_context { + * @node: hlist node for the console list + * + * @write_atomic: Write callback for atomic context ++ * @write_thread: Write callback for non-atomic context + * @driver_enter: Callback to begin synchronization with driver code + * @driver_exit: Callback to finish synchronization with driver code + * @nbcon_state: State for nbcon consoles + * @nbcon_seq: Sequence number of the next record for nbcon to print + * @pbufs: Pointer to nbcon private buffer + * @locked_port: True, if the port lock is locked by nbcon ++ * @kthread: Printer kthread for this console ++ * @rcuwait: RCU-safe wait object for @kthread waking + */ + struct console { + char name[16]; +@@ -325,12 +329,16 @@ struct console { + /* nbcon console specific members */ + bool (*write_atomic)(struct console *con, + struct nbcon_write_context *wctxt); ++ bool (*write_thread)(struct console *con, ++ struct nbcon_write_context *wctxt); + void (*driver_enter)(struct console *con, unsigned long *flags); + void (*driver_exit)(struct console *con, unsigned long flags); + atomic_t __private nbcon_state; + atomic_long_t __private nbcon_seq; + struct printk_buffers *pbufs; + bool locked_port; ++ struct task_struct *kthread; ++ struct rcuwait rcuwait; + }; + + #ifdef CONFIG_LOCKDEP +--- a/kernel/printk/internal.h ++++ b/kernel/printk/internal.h +@@ -92,6 +92,7 @@ void nbcon_free(struct console *con); + enum nbcon_prio nbcon_get_default_prio(void); + void nbcon_atomic_flush_all(void); + bool nbcon_atomic_emit_next_record(struct console *con, bool *handover, int cookie); ++void nbcon_kthread_create(struct console *con); + + /* + * Check if the given console is currently capable and allowed to print +@@ -110,6 +111,8 @@ static inline bool console_is_usable(str + if (flags & CON_NBCON) { + if (!con->write_atomic) + return false; ++ if (!con->write_thread || !con->kthread) ++ return false; + } else { + if (!con->write) + return false; +@@ -126,12 +129,34 @@ static inline bool console_is_usable(str + return true; + } + ++/** ++ * nbcon_kthread_wake - Wake up a printk thread ++ * @con: Console to operate on ++ */ ++static inline void nbcon_kthread_wake(struct console *con) ++{ ++ /* ++ * Guarantee any new records can be seen by tasks preparing to wait ++ * before this context checks if the rcuwait is empty. ++ * ++ * The full memory barrier in rcuwait_wake_up() pairs with the full ++ * memory barrier within set_current_state() of ++ * ___rcuwait_wait_event(), which is called after prepare_to_rcuwait() ++ * adds the waiter but before it has checked the wait condition. ++ * ++ * This pairs with nbcon_kthread_func:A. ++ */ ++ rcuwait_wake_up(&con->rcuwait); /* LMM(nbcon_kthread_wake:A) */ ++} ++ + #else + + #define PRINTK_PREFIX_MAX 0 + #define PRINTK_MESSAGE_MAX 0 + #define PRINTKRB_RECORD_MAX 0 + ++static inline void nbcon_kthread_wake(struct console *con) { } ++static inline void nbcon_kthread_create(struct console *con) { } + #define printing_via_unlock (false) + + /* +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -5,8 +5,10 @@ + #include + #include + #include ++#include + #include + #include ++#include "printk_ringbuffer.h" + #include "internal.h" + /* + * Printk console printing implementation for consoles which does not depend +@@ -828,6 +830,7 @@ EXPORT_SYMBOL_GPL(nbcon_exit_unsafe); + /** + * nbcon_emit_next_record - Emit a record in the acquired context + * @wctxt: The write context that will be handed to the write function ++ * @use_atomic: True if the write_atomic callback is to be used + * + * Return: True if this context still owns the console. False if + * ownership was handed over or taken. +@@ -841,7 +844,7 @@ EXPORT_SYMBOL_GPL(nbcon_exit_unsafe); + * When true is returned, @wctxt->ctxt.backlog indicates whether there are + * still records pending in the ringbuffer, + */ +-static bool nbcon_emit_next_record(struct nbcon_write_context *wctxt) ++static bool nbcon_emit_next_record(struct nbcon_write_context *wctxt, bool use_atomic) + { + struct nbcon_context *ctxt = &ACCESS_PRIVATE(wctxt, ctxt); + struct console *con = ctxt->console; +@@ -891,9 +894,17 @@ static bool nbcon_emit_next_record(struc + nbcon_state_read(con, &cur); + wctxt->unsafe_takeover = cur.unsafe_takeover; + +- if (con->write_atomic) ++ if (use_atomic && ++ con->write_atomic) { + done = con->write_atomic(con, wctxt); + ++ } else if (!use_atomic && ++ con->write_thread && ++ con->kthread) { ++ WARN_ON_ONCE(con->kthread != current); ++ done = con->write_thread(con, wctxt); ++ } ++ + if (!done) { + /* + * The emit was aborted, probably due to a loss of ownership. +@@ -929,6 +940,118 @@ static bool nbcon_emit_next_record(struc + return nbcon_context_exit_unsafe(ctxt); + } + ++/** ++ * nbcon_kthread_should_wakeup - Check whether a printer thread should wakeup ++ * @con: Console to operate on ++ * @ctxt: The acquire context that contains the state ++ * at console_acquire() ++ * ++ * Return: True if the thread should shutdown or if the console is ++ * allowed to print and a record is available. False otherwise. ++ * ++ * After the thread wakes up, it must first check if it should shutdown before ++ * attempting any printing. ++ */ ++static bool nbcon_kthread_should_wakeup(struct console *con, struct nbcon_context *ctxt) ++{ ++ bool is_usable; ++ short flags; ++ int cookie; ++ ++ if (kthread_should_stop()) ++ return true; ++ ++ cookie = console_srcu_read_lock(); ++ flags = console_srcu_read_flags(con); ++ is_usable = console_is_usable(con, flags); ++ console_srcu_read_unlock(cookie); ++ ++ if (!is_usable) ++ return false; ++ ++ /* Bring the sequence in @ctxt up to date */ ++ ctxt->seq = nbcon_seq_read(con); ++ ++ return prb_read_valid(prb, ctxt->seq, NULL); ++} ++ ++/** ++ * nbcon_kthread_func - The printer thread function ++ * @__console: Console to operate on ++ */ ++static int nbcon_kthread_func(void *__console) ++{ ++ struct console *con = __console; ++ struct nbcon_write_context wctxt = { ++ .ctxt.console = con, ++ .ctxt.prio = NBCON_PRIO_NORMAL, ++ }; ++ struct nbcon_context *ctxt = &ACCESS_PRIVATE(&wctxt, ctxt); ++ unsigned long flags; ++ short con_flags; ++ bool backlog; ++ int cookie; ++ int ret; ++ ++wait_for_event: ++ /* ++ * Guarantee this task is visible on the rcuwait before ++ * checking the wake condition. ++ * ++ * The full memory barrier within set_current_state() of ++ * ___rcuwait_wait_event() pairs with the full memory ++ * barrier within rcuwait_has_sleeper(). ++ * ++ * This pairs with rcuwait_has_sleeper:A and nbcon_kthread_wake:A. ++ */ ++ ret = rcuwait_wait_event(&con->rcuwait, ++ nbcon_kthread_should_wakeup(con, ctxt), ++ TASK_INTERRUPTIBLE); /* LMM(nbcon_kthread_func:A) */ ++ ++ if (kthread_should_stop()) ++ return 0; ++ ++ /* Wait was interrupted by a spurious signal, go back to sleep. */ ++ if (ret) ++ goto wait_for_event; ++ ++ do { ++ backlog = false; ++ ++ cookie = console_srcu_read_lock(); ++ ++ con_flags = console_srcu_read_flags(con); ++ ++ if (console_is_usable(con, con_flags)) { ++ con->driver_enter(con, &flags); ++ ++ /* ++ * Ensure this stays on the CPU to make handover and ++ * takeover possible. ++ */ ++ cant_migrate(); ++ ++ if (nbcon_context_try_acquire(ctxt)) { ++ /* ++ * If the emit fails, this context is no ++ * longer the owner. ++ */ ++ if (nbcon_emit_next_record(&wctxt, false)) { ++ nbcon_context_release(ctxt); ++ backlog = ctxt->backlog; ++ } ++ } ++ ++ con->driver_exit(con, flags); ++ } ++ ++ console_srcu_read_unlock(cookie); ++ ++ } while (backlog); ++ ++ goto wait_for_event; ++} ++ + /* Track the nbcon emergency nesting per CPU. */ + static DEFINE_PER_CPU(unsigned int, nbcon_pcpu_emergency_nesting); + static unsigned int early_nbcon_pcpu_emergency_nesting __initdata; +@@ -976,7 +1099,7 @@ static bool nbcon_atomic_emit_one(struct + * handed over or taken over. In both cases the context is no + * longer valid. + */ +- if (!nbcon_emit_next_record(wctxt)) ++ if (!nbcon_emit_next_record(wctxt, true)) + return false; + + nbcon_context_release(ctxt); +@@ -1192,6 +1315,63 @@ void nbcon_cpu_emergency_exit(void) + } + + /** ++ * nbcon_kthread_stop - Stop a printer thread ++ * @con: Console to operate on ++ */ ++static void nbcon_kthread_stop(struct console *con) ++{ ++ lockdep_assert_console_list_lock_held(); ++ ++ if (!con->kthread) ++ return; ++ ++ kthread_stop(con->kthread); ++ con->kthread = NULL; ++} ++ ++/** ++ * nbcon_kthread_create - Create a printer thread ++ * @con: Console to operate on ++ * ++ * If it fails, let the console proceed. The atomic part might ++ * be usable and useful. ++ */ ++void nbcon_kthread_create(struct console *con) ++{ ++ struct task_struct *kt; ++ ++ lockdep_assert_console_list_lock_held(); ++ ++ if (!(con->flags & CON_NBCON) || !con->write_thread) ++ return; ++ ++ if (con->kthread) ++ return; ++ ++ /* ++ * Printer threads cannot be started as long as any boot console is ++ * registered because there is no way to synchronize the hardware ++ * registers between boot console code and regular console code. ++ */ ++ if (have_boot_console) ++ return; ++ ++ kt = kthread_run(nbcon_kthread_func, con, "pr/%s%d", con->name, con->index); ++ if (IS_ERR(kt)) { ++ con_printk(KERN_ERR, con, "failed to start printing thread\n"); ++ return; ++ } ++ ++ con->kthread = kt; ++ ++ /* ++ * It is important that console printing threads are scheduled ++ * shortly after a printk call and with generous runtime budgets. ++ */ ++ sched_set_normal(con->kthread, -20); ++} ++ ++/** + * nbcon_alloc - Allocate buffers needed by the nbcon console + * @con: Console to allocate buffers for + * +@@ -1237,6 +1417,7 @@ void nbcon_init(struct console *con) + /* nbcon_alloc() must have been called and successful! */ + BUG_ON(!con->pbufs); + ++ rcuwait_init(&con->rcuwait); + nbcon_seq_force(con, con->seq); + nbcon_state_set(con, &state); + } +@@ -1249,6 +1430,7 @@ void nbcon_free(struct console *con) + { + struct nbcon_state state = { }; + ++ nbcon_kthread_stop(con); + nbcon_state_set(con, &state); + + /* Boot consoles share global printk buffers. */ +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -2682,6 +2682,8 @@ void suspend_console(void) + void resume_console(void) + { + struct console *con; ++ short flags; ++ int cookie; + + if (!console_suspend_enabled) + return; +@@ -2698,6 +2700,14 @@ void resume_console(void) + */ + synchronize_srcu(&console_srcu); + ++ cookie = console_srcu_read_lock(); ++ for_each_console_srcu(con) { ++ flags = console_srcu_read_flags(con); ++ if (flags & CON_NBCON) ++ nbcon_kthread_wake(con); ++ } ++ console_srcu_read_unlock(cookie); ++ + pr_flush(1000, true); + } + +@@ -3018,6 +3028,13 @@ static bool console_flush_all(bool do_co + u64 printk_seq; + bool progress; + ++ /* ++ * console_flush_all() is only for legacy consoles, ++ * unless the nbcon console has no kthread printer. ++ */ ++ if ((flags & CON_NBCON) && con->kthread) ++ continue; ++ + if (!console_is_usable(con, flags)) + continue; + any_usable = true; +@@ -3313,9 +3330,23 @@ EXPORT_SYMBOL(console_stop); + + void console_start(struct console *console) + { ++ short flags; ++ + console_list_lock(); + console_srcu_write_flags(console, console->flags | CON_ENABLED); ++ flags = console->flags; + console_list_unlock(); ++ ++ /* ++ * Ensure that all SRCU list walks have completed. The related ++ * printing context must be able to see it is enabled so that ++ * it is guaranteed to wake up and resume printing. ++ */ ++ synchronize_srcu(&console_srcu); ++ ++ if (flags & CON_NBCON) ++ nbcon_kthread_wake(console); ++ + __pr_flush(console, 1000, true); + } + EXPORT_SYMBOL(console_start); diff --git a/debian/patches-rt/0122-printk-Atomic-print-in-printk-context-on-shutdown.patch b/debian/patches-rt/0122-printk-Atomic-print-in-printk-context-on-shutdown.patch new file mode 100644 index 000000000..35c88289b --- /dev/null +++ b/debian/patches-rt/0122-printk-Atomic-print-in-printk-context-on-shutdown.patch @@ -0,0 +1,41 @@ +From: John Ogness +Date: Mon, 23 Oct 2023 17:43:48 +0000 +Subject: [PATCH 122/134] printk: Atomic print in printk context on shutdown +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +For nbcon consoles, normally the printing is handled by the +dedicated console printing threads. However, on shutdown the +printing threads may not get a chance to print the final +messages. + +When shutting down or rebooting (system_state > SYSTEM_RUNNING), +perform atomic printing from the printk() caller context. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/printk.c | 7 ++++++- + 1 file changed, 6 insertions(+), 1 deletion(-) + +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -2389,13 +2389,18 @@ asmlinkage int vprintk_emit(int facility + * + * - When this CPU is in panic. + * ++ * - During shutdown, since the printing threads may not get ++ * a chance to print the final messages. ++ * + * Note that if boot consoles are registered, the + * console_lock/console_unlock dance must be relied upon + * instead because nbcon consoles cannot print simultaneously + * with boot consoles. + */ +- if (is_panic_context) ++ if (is_panic_context || ++ (system_state > SYSTEM_RUNNING)) { + nbcon_atomic_flush_all(); ++ } + } + + if (do_trylock_unlock) { diff --git a/debian/patches-rt/0123-printk-nbcon-Add-context-to-console_is_usable.patch b/debian/patches-rt/0123-printk-nbcon-Add-context-to-console_is_usable.patch new file mode 100644 index 000000000..26a494c16 --- /dev/null +++ b/debian/patches-rt/0123-printk-nbcon-Add-context-to-console_is_usable.patch @@ -0,0 +1,111 @@ +From: John Ogness +Date: Tue, 26 Sep 2023 14:43:30 +0000 +Subject: [PATCH 123/134] printk: nbcon: Add context to console_is_usable() +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +The nbcon consoles have two callbacks to be used for different +contexts. In order to determine if an nbcon console is usable, +console_is_usable() needs to know if it is a context that will +use the write_atomic() callback or the write_thread() callback. + +Add an extra parameter @use_atomic to specify this. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/internal.h | 16 ++++++++++------ + kernel/printk/nbcon.c | 6 +++--- + kernel/printk/printk.c | 6 ++++-- + 3 files changed, 17 insertions(+), 11 deletions(-) + +--- a/kernel/printk/internal.h ++++ b/kernel/printk/internal.h +@@ -100,7 +100,7 @@ void nbcon_kthread_create(struct console + * which can also play a role in deciding if @con can be used to print + * records. + */ +-static inline bool console_is_usable(struct console *con, short flags) ++static inline bool console_is_usable(struct console *con, short flags, bool use_atomic) + { + if (!(flags & CON_ENABLED)) + return false; +@@ -109,10 +109,13 @@ static inline bool console_is_usable(str + return false; + + if (flags & CON_NBCON) { +- if (!con->write_atomic) +- return false; +- if (!con->write_thread || !con->kthread) +- return false; ++ if (use_atomic) { ++ if (!con->write_atomic) ++ return false; ++ } else { ++ if (!con->write_thread || !con->kthread) ++ return false; ++ } + } else { + if (!con->write) + return false; +@@ -178,7 +181,8 @@ static inline void nbcon_atomic_flush_al + static inline bool nbcon_atomic_emit_next_record(struct console *con, bool *handover, + int cookie) { return false; } + +-static inline bool console_is_usable(struct console *con, short flags) { return false; } ++static inline bool console_is_usable(struct console *con, short flags, ++ bool use_atomic) { return false; } + + #endif /* CONFIG_PRINTK */ + +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -963,7 +963,7 @@ static bool nbcon_kthread_should_wakeup( + + cookie = console_srcu_read_lock(); + flags = console_srcu_read_flags(con); +- is_usable = console_is_usable(con, flags); ++ is_usable = console_is_usable(con, flags, false); + console_srcu_read_unlock(cookie); + + if (!is_usable) +@@ -1022,7 +1022,7 @@ static int nbcon_kthread_func(void *__co + + con_flags = console_srcu_read_flags(con); + +- if (console_is_usable(con, con_flags)) { ++ if (console_is_usable(con, con_flags, false)) { + con->driver_enter(con, &flags); + + /* +@@ -1203,7 +1203,7 @@ static void __nbcon_atomic_flush_all(u64 + if (!(flags & CON_NBCON)) + continue; + +- if (!console_is_usable(con, flags)) ++ if (!console_is_usable(con, flags, true)) + continue; + + if (nbcon_seq_read(con) >= stop_seq) +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -3040,7 +3040,7 @@ static bool console_flush_all(bool do_co + if ((flags & CON_NBCON) && con->kthread) + continue; + +- if (!console_is_usable(con, flags)) ++ if (!console_is_usable(con, flags, true)) + continue; + any_usable = true; + +@@ -3945,8 +3945,10 @@ static bool __pr_flush(struct console *c + * that they make forward progress, so only increment + * @diff for usable consoles. + */ +- if (!console_is_usable(c, flags)) ++ if (!console_is_usable(c, flags, true) && ++ !console_is_usable(c, flags, false)) { + continue; ++ } + + if (flags & CON_NBCON) { + printk_seq = nbcon_seq_read(c); diff --git a/debian/patches-rt/0124-printk-nbcon-Add-printer-thread-wakeups.patch b/debian/patches-rt/0124-printk-nbcon-Add-printer-thread-wakeups.patch new file mode 100644 index 000000000..18e02593f --- /dev/null +++ b/debian/patches-rt/0124-printk-nbcon-Add-printer-thread-wakeups.patch @@ -0,0 +1,164 @@ +From: Thomas Gleixner +Date: Tue, 26 Sep 2023 13:03:52 +0000 +Subject: [PATCH 124/134] printk: nbcon: Add printer thread wakeups +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Add a function to wakeup the printer threads. Use the new function +when: + + - records are added to the printk ringbuffer + - consoles are resumed + - triggered via printk_trigger_flush() + +The actual waking is performed via irq_work so that the wakeup can +be triggered from any context. + +Co-developed-by: John Ogness +Signed-off-by: John Ogness +Signed-off-by: Thomas Gleixner (Intel) +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/console.h | 3 ++ + kernel/printk/internal.h | 1 + kernel/printk/nbcon.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++ + kernel/printk/printk.c | 7 +++++ + 4 files changed, 67 insertions(+) + +--- a/include/linux/console.h ++++ b/include/linux/console.h +@@ -16,6 +16,7 @@ + + #include + #include ++#include + #include + #include + #include +@@ -306,6 +307,7 @@ struct nbcon_write_context { + * @locked_port: True, if the port lock is locked by nbcon + * @kthread: Printer kthread for this console + * @rcuwait: RCU-safe wait object for @kthread waking ++ * @irq_work: Defer @kthread waking to IRQ work context + */ + struct console { + char name[16]; +@@ -339,6 +341,7 @@ struct console { + bool locked_port; + struct task_struct *kthread; + struct rcuwait rcuwait; ++ struct irq_work irq_work; + }; + + #ifdef CONFIG_LOCKDEP +--- a/kernel/printk/internal.h ++++ b/kernel/printk/internal.h +@@ -93,6 +93,7 @@ enum nbcon_prio nbcon_get_default_prio(v + void nbcon_atomic_flush_all(void); + bool nbcon_atomic_emit_next_record(struct console *con, bool *handover, int cookie); + void nbcon_kthread_create(struct console *con); ++void nbcon_wake_threads(void); + + /* + * Check if the given console is currently capable and allowed to print +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -1052,6 +1052,61 @@ static int nbcon_kthread_func(void *__co + goto wait_for_event; + } + ++/** ++ * nbcon_irq_work - irq work to wake printk thread ++ * @irq_work: The irq work to operate on ++ */ ++static void nbcon_irq_work(struct irq_work *irq_work) ++{ ++ struct console *con = container_of(irq_work, struct console, irq_work); ++ ++ nbcon_kthread_wake(con); ++} ++ ++static inline bool rcuwait_has_sleeper(struct rcuwait *w) ++{ ++ bool has_sleeper; ++ ++ rcu_read_lock(); ++ /* ++ * Guarantee any new records can be seen by tasks preparing to wait ++ * before this context checks if the rcuwait is empty. ++ * ++ * This full memory barrier pairs with the full memory barrier within ++ * set_current_state() of ___rcuwait_wait_event(), which is called ++ * after prepare_to_rcuwait() adds the waiter but before it has ++ * checked the wait condition. ++ * ++ * This pairs with nbcon_kthread_func:A. ++ */ ++ smp_mb(); /* LMM(rcuwait_has_sleeper:A) */ ++ has_sleeper = !!rcu_dereference(w->task); ++ rcu_read_unlock(); ++ ++ return has_sleeper; ++} ++ ++/** ++ * nbcon_wake_threads - Wake up printing threads using irq_work ++ */ ++void nbcon_wake_threads(void) ++{ ++ struct console *con; ++ int cookie; ++ ++ cookie = console_srcu_read_lock(); ++ for_each_console_srcu(con) { ++ /* ++ * Only schedule irq_work if the printing thread is ++ * actively waiting. If not waiting, the thread will ++ * notice by itself that it has work to do. ++ */ ++ if (con->kthread && rcuwait_has_sleeper(&con->rcuwait)) ++ irq_work_queue(&con->irq_work); ++ } ++ console_srcu_read_unlock(cookie); ++} ++ + /* Track the nbcon emergency nesting per CPU. */ + static DEFINE_PER_CPU(unsigned int, nbcon_pcpu_emergency_nesting); + static unsigned int early_nbcon_pcpu_emergency_nesting __initdata; +@@ -1418,6 +1473,7 @@ void nbcon_init(struct console *con) + BUG_ON(!con->pbufs); + + rcuwait_init(&con->rcuwait); ++ init_irq_work(&con->irq_work, nbcon_irq_work); + nbcon_seq_force(con, con->seq); + nbcon_state_set(con, &state); + } +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -2403,6 +2403,8 @@ asmlinkage int vprintk_emit(int facility + } + } + ++ nbcon_wake_threads(); ++ + if (do_trylock_unlock) { + /* + * The caller may be holding system-critical or +@@ -2705,6 +2707,10 @@ void resume_console(void) + */ + synchronize_srcu(&console_srcu); + ++ /* ++ * Since this runs in task context, wake the threaded printers ++ * directly rather than scheduling irq_work to do it. ++ */ + cookie = console_srcu_read_lock(); + for_each_console_srcu(con) { + flags = console_srcu_read_flags(con); +@@ -4097,6 +4103,7 @@ void defer_console_output(void) + + void printk_trigger_flush(void) + { ++ nbcon_wake_threads(); + defer_console_output(); + } + diff --git a/debian/patches-rt/0125-printk-nbcon-Stop-threads-on-shutdown-reboot.patch b/debian/patches-rt/0125-printk-nbcon-Stop-threads-on-shutdown-reboot.patch new file mode 100644 index 000000000..55ec76c5c --- /dev/null +++ b/debian/patches-rt/0125-printk-nbcon-Stop-threads-on-shutdown-reboot.patch @@ -0,0 +1,60 @@ +From: John Ogness +Date: Tue, 26 Sep 2023 13:04:15 +0000 +Subject: [PATCH 125/134] printk: nbcon: Stop threads on shutdown/reboot +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Register a syscore_ops shutdown function to stop all threaded +printers on shutdown/reboot. This allows printk to transition back +to atomic printing in order to provide a robust mechanism for +outputting the final messages. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/nbcon.c | 31 +++++++++++++++++++++++++++++++ + 1 file changed, 31 insertions(+) + +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -8,6 +8,7 @@ + #include + #include + #include ++#include + #include "printk_ringbuffer.h" + #include "internal.h" + /* +@@ -1577,3 +1578,33 @@ void nbcon_release(struct uart_port *up) + con->locked_port = false; + } + EXPORT_SYMBOL_GPL(nbcon_release); ++ ++/** ++ * printk_kthread_shutdown - shutdown all threaded printers ++ * ++ * On system shutdown all threaded printers are stopped. This allows printk ++ * to transition back to atomic printing, thus providing a robust mechanism ++ * for the final shutdown/reboot messages to be output. ++ */ ++static void printk_kthread_shutdown(void) ++{ ++ struct console *con; ++ ++ console_list_lock(); ++ for_each_console(con) { ++ if (con->flags & CON_NBCON) ++ nbcon_kthread_stop(con); ++ } ++ console_list_unlock(); ++} ++ ++static struct syscore_ops printk_syscore_ops = { ++ .shutdown = printk_kthread_shutdown, ++}; ++ ++static int __init printk_init_ops(void) ++{ ++ register_syscore_ops(&printk_syscore_ops); ++ return 0; ++} ++device_initcall(printk_init_ops); diff --git a/debian/patches-rt/0126-printk-nbcon-Start-printing-threads.patch b/debian/patches-rt/0126-printk-nbcon-Start-printing-threads.patch new file mode 100644 index 000000000..ec4122163 --- /dev/null +++ b/debian/patches-rt/0126-printk-nbcon-Start-printing-threads.patch @@ -0,0 +1,135 @@ +From: John Ogness +Date: Tue, 5 Dec 2023 14:09:31 +0000 +Subject: [PATCH 126/134] printk: nbcon: Start printing threads +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +If there are no boot consoles, the printing threads are started +in early_initcall. + +If there are boot consoles, the printing threads are started +after the last boot console has unregistered. The printing +threads do not need to be concerned about boot consoles because +boot consoles cannot register once a non-boot console has +registered. + +Until a printing thread of a console has started, that console +will print using atomic_write() in the printk() caller context. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/internal.h | 2 ++ + kernel/printk/nbcon.c | 18 +++++++++++++++++- + kernel/printk/printk.c | 14 ++++++++++++++ + 3 files changed, 33 insertions(+), 1 deletion(-) + +--- a/kernel/printk/internal.h ++++ b/kernel/printk/internal.h +@@ -44,6 +44,7 @@ enum printk_info_flags { + }; + + extern struct printk_ringbuffer *prb; ++extern bool printk_threads_enabled; + extern bool have_legacy_console; + extern bool have_boot_console; + +@@ -161,6 +162,7 @@ static inline void nbcon_kthread_wake(st + + static inline void nbcon_kthread_wake(struct console *con) { } + static inline void nbcon_kthread_create(struct console *con) { } ++#define printk_threads_enabled (false) + #define printing_via_unlock (false) + + /* +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -205,6 +205,8 @@ static void nbcon_seq_try_update(struct + } + } + ++bool printk_threads_enabled __ro_after_init; ++ + /** + * nbcon_context_try_acquire_direct - Try to acquire directly + * @ctxt: The context of the caller +@@ -1401,7 +1403,7 @@ void nbcon_kthread_create(struct console + if (!(con->flags & CON_NBCON) || !con->write_thread) + return; + +- if (con->kthread) ++ if (!printk_threads_enabled || con->kthread) + return; + + /* +@@ -1427,6 +1429,19 @@ void nbcon_kthread_create(struct console + sched_set_normal(con->kthread, -20); + } + ++static int __init printk_setup_threads(void) ++{ ++ struct console *con; ++ ++ console_list_lock(); ++ printk_threads_enabled = true; ++ for_each_console(con) ++ nbcon_kthread_create(con); ++ console_list_unlock(); ++ return 0; ++} ++early_initcall(printk_setup_threads); ++ + /** + * nbcon_alloc - Allocate buffers needed by the nbcon console + * @con: Console to allocate buffers for +@@ -1477,6 +1492,7 @@ void nbcon_init(struct console *con) + init_irq_work(&con->irq_work, nbcon_irq_work); + nbcon_seq_force(con, con->seq); + nbcon_state_set(con, &state); ++ nbcon_kthread_create(con); + } + + /** +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -2389,6 +2389,9 @@ asmlinkage int vprintk_emit(int facility + * + * - When this CPU is in panic. + * ++ * - When booting, before the printing threads have been ++ * started. ++ * + * - During shutdown, since the printing threads may not get + * a chance to print the final messages. + * +@@ -2398,6 +2401,7 @@ asmlinkage int vprintk_emit(int facility + * with boot consoles. + */ + if (is_panic_context || ++ !printk_threads_enabled || + (system_state > SYSTEM_RUNNING)) { + nbcon_atomic_flush_all(); + } +@@ -3685,6 +3689,7 @@ EXPORT_SYMBOL(register_console); + /* Must be called under console_list_lock(). */ + static int unregister_console_locked(struct console *console) + { ++ bool is_boot_con = (console->flags & CON_BOOT); + bool found_legacy_con = false; + bool found_nbcon_con = false; + bool found_boot_con = false; +@@ -3756,6 +3761,15 @@ static int unregister_console_locked(str + if (!found_nbcon_con) + have_nbcon_console = false; + ++ /* ++ * When the last boot console unregisters, start up the ++ * printing threads. ++ */ ++ if (is_boot_con && !have_boot_console) { ++ for_each_console(c) ++ nbcon_kthread_create(c); ++ } ++ + return res; + } + diff --git a/debian/patches-rt/0127-proc-Add-nbcon-support-for-proc-consoles.patch b/debian/patches-rt/0127-proc-Add-nbcon-support-for-proc-consoles.patch new file mode 100644 index 000000000..615ecb02a --- /dev/null +++ b/debian/patches-rt/0127-proc-Add-nbcon-support-for-proc-consoles.patch @@ -0,0 +1,53 @@ +From: John Ogness +Date: Tue, 26 Sep 2023 13:31:00 +0000 +Subject: [PATCH 127/134] proc: Add nbcon support for /proc/consoles +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Update /proc/consoles output to show 'W' if an nbcon write +callback is implemented (write_atomic or write_thread). + +Also update /proc/consoles output to show 'N' if it is an +nbcon console. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + fs/proc/consoles.c | 14 +++++++++++--- + 1 file changed, 11 insertions(+), 3 deletions(-) + +--- a/fs/proc/consoles.c ++++ b/fs/proc/consoles.c +@@ -21,12 +21,14 @@ static int show_console_dev(struct seq_f + { CON_ENABLED, 'E' }, + { CON_CONSDEV, 'C' }, + { CON_BOOT, 'B' }, ++ { CON_NBCON, 'N' }, + { CON_PRINTBUFFER, 'p' }, + { CON_BRL, 'b' }, + { CON_ANYTIME, 'a' }, + }; + char flags[ARRAY_SIZE(con_flags) + 1]; + struct console *con = v; ++ char con_write = '-'; + unsigned int a; + dev_t dev = 0; + +@@ -57,9 +59,15 @@ static int show_console_dev(struct seq_f + seq_setwidth(m, 21 - 1); + seq_printf(m, "%s%d", con->name, con->index); + seq_pad(m, ' '); +- seq_printf(m, "%c%c%c (%s)", con->read ? 'R' : '-', +- con->write ? 'W' : '-', con->unblank ? 'U' : '-', +- flags); ++ if (con->flags & CON_NBCON) { ++ if (con->write_atomic || con->write_thread) ++ con_write = 'W'; ++ } else { ++ if (con->write) ++ con_write = 'W'; ++ } ++ seq_printf(m, "%c%c%c (%s)", con->read ? 'R' : '-', con_write, ++ con->unblank ? 'U' : '-', flags); + if (dev) + seq_printf(m, " %4d:%d", MAJOR(dev), MINOR(dev)); + diff --git a/debian/patches-rt/0128-tty-sysfs-Add-nbcon-support-for-active.patch b/debian/patches-rt/0128-tty-sysfs-Add-nbcon-support-for-active.patch new file mode 100644 index 000000000..f8b285f43 --- /dev/null +++ b/debian/patches-rt/0128-tty-sysfs-Add-nbcon-support-for-active.patch @@ -0,0 +1,33 @@ +From: John Ogness +Date: Fri, 22 Sep 2023 14:31:09 +0000 +Subject: [PATCH 128/134] tty: sysfs: Add nbcon support for 'active' +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Allow the 'active' attribute to list nbcon consoles. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/tty_io.c | 11 +++++++++-- + 1 file changed, 9 insertions(+), 2 deletions(-) + +--- a/drivers/tty/tty_io.c ++++ b/drivers/tty/tty_io.c +@@ -3540,8 +3540,15 @@ static ssize_t show_cons_active(struct d + for_each_console(c) { + if (!c->device) + continue; +- if (!c->write) +- continue; ++ if (c->flags & CON_NBCON) { ++ if (!c->write_atomic && ++ !(c->write_thread && c->kthread)) { ++ continue; ++ } ++ } else { ++ if (!c->write) ++ continue; ++ } + if ((c->flags & CON_ENABLED) == 0) + continue; + cs[i++] = c; diff --git a/debian/patches-rt/0129-printk-nbcon-Provide-function-to-reacquire-ownership.patch b/debian/patches-rt/0129-printk-nbcon-Provide-function-to-reacquire-ownership.patch new file mode 100644 index 000000000..e878a4b1b --- /dev/null +++ b/debian/patches-rt/0129-printk-nbcon-Provide-function-to-reacquire-ownership.patch @@ -0,0 +1,92 @@ +From: John Ogness +Date: Fri, 20 Oct 2023 10:01:58 +0000 +Subject: [PATCH 129/134] printk: nbcon: Provide function to reacquire + ownership +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Contexts may become nbcon owners for various reasons, not just +for printing. Indeed, the port->lock wrapper takes ownership +for anything relating to the hardware. + +Since ownership can be lost at any time due to handover or +takeover, a context _should_ be prepared to back out +immediately and carefully. However, there are many scenarios +where the context _must_ reacquire ownership in order to +finalize or revert hardware changes. + +One such example is when interrupts are disabled by a context. +No other context will automagically re-enable the interrupts. +For this case, the disabling context _must_ reacquire nbcon +ownership so that it can re-enable the interrupts. + +Provide nbcon_reacquire() for exactly this purpose. + +Note that for printing contexts, after a successful reacquire +the context will have no output buffer because that has been +lost. nbcon_reacquire() cannot be used to resume printing. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/console.h | 2 ++ + kernel/printk/nbcon.c | 32 ++++++++++++++++++++++++++++++++ + 2 files changed, 34 insertions(+) + +--- a/include/linux/console.h ++++ b/include/linux/console.h +@@ -474,12 +474,14 @@ extern void nbcon_cpu_emergency_exit(voi + extern bool nbcon_can_proceed(struct nbcon_write_context *wctxt); + extern bool nbcon_enter_unsafe(struct nbcon_write_context *wctxt); + extern bool nbcon_exit_unsafe(struct nbcon_write_context *wctxt); ++extern void nbcon_reacquire(struct nbcon_write_context *wctxt); + #else + static inline void nbcon_cpu_emergency_enter(void) { } + static inline void nbcon_cpu_emergency_exit(void) { } + static inline bool nbcon_can_proceed(struct nbcon_write_context *wctxt) { return false; } + static inline bool nbcon_enter_unsafe(struct nbcon_write_context *wctxt) { return false; } + static inline bool nbcon_exit_unsafe(struct nbcon_write_context *wctxt) { return false; } ++static inline void nbcon_reacquire(struct nbcon_write_context *wctxt) { } + #endif + + extern int console_set_on_cmdline; +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -831,6 +831,38 @@ bool nbcon_exit_unsafe(struct nbcon_writ + EXPORT_SYMBOL_GPL(nbcon_exit_unsafe); + + /** ++ * nbcon_reacquire - Reacquire a console after losing ownership ++ * @wctxt: The write context that was handed to the write function ++ * ++ * Since ownership can be lost at any time due to handover or takeover, a ++ * printing context _should_ be prepared to back out immediately and ++ * carefully. However, there are many scenarios where the context _must_ ++ * reacquire ownership in order to finalize or revert hardware changes. ++ * ++ * This function allows a context to reacquire ownership using the same ++ * priority as its previous ownership. ++ * ++ * Note that for printing contexts, after a successful reacquire the ++ * context will have no output buffer because that has been lost. This ++ * function cannot be used to resume printing. ++ */ ++void nbcon_reacquire(struct nbcon_write_context *wctxt) ++{ ++ struct nbcon_context *ctxt = &ACCESS_PRIVATE(wctxt, ctxt); ++ struct console *con = ctxt->console; ++ struct nbcon_state cur; ++ ++ while (!nbcon_context_try_acquire(ctxt)) ++ cpu_relax(); ++ ++ wctxt->outbuf = NULL; ++ wctxt->len = 0; ++ nbcon_state_read(con, &cur); ++ wctxt->unsafe_takeover = cur.unsafe_takeover; ++} ++EXPORT_SYMBOL_GPL(nbcon_reacquire); ++ ++/** + * nbcon_emit_next_record - Emit a record in the acquired context + * @wctxt: The write context that will be handed to the write function + * @use_atomic: True if the write_atomic callback is to be used diff --git a/debian/patches-rt/0130-serial-core-Provide-low-level-functions-to-port-lock.patch b/debian/patches-rt/0130-serial-core-Provide-low-level-functions-to-port-lock.patch new file mode 100644 index 000000000..e8e506fe5 --- /dev/null +++ b/debian/patches-rt/0130-serial-core-Provide-low-level-functions-to-port-lock.patch @@ -0,0 +1,43 @@ +From: John Ogness +Date: Mon, 11 Dec 2023 09:19:18 +0000 +Subject: [PATCH 130/134] serial: core: Provide low-level functions to port + lock +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +The nbcon console's driver_enter() and driver_exit() callbacks need +to lock the port lock in order to synchronize against other hardware +activity (such as adjusting baud rates). However, they cannot use +the uart_port_lock() wrappers because the printk subsystem will +perform nbcon locking after calling the driver_enter() callback. + +Provide low-level variants __uart_port_lock_irqsave() and +__uart_port_unlock_irqrestore() for this purpose. These are only +to be used by the driver_enter()/driver_exit() callbacks. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/serial_core.h | 12 ++++++++++++ + 1 file changed, 12 insertions(+) + +--- a/include/linux/serial_core.h ++++ b/include/linux/serial_core.h +@@ -681,6 +681,18 @@ static inline void uart_port_unlock_irqr + spin_unlock_irqrestore(&up->lock, flags); + } + ++/* Only for use in the console->driver_enter() callback. */ ++static inline void __uart_port_lock_irqsave(struct uart_port *up, unsigned long *flags) ++{ ++ spin_lock_irqsave(&up->lock, *flags); ++} ++ ++/* Only for use in the console->driver_exit() callback. */ ++static inline void __uart_port_unlock_irqrestore(struct uart_port *up, unsigned long flags) ++{ ++ spin_unlock_irqrestore(&up->lock, flags); ++} ++ + static inline int serial_port_in(struct uart_port *up, int offset) + { + return up->serial_in(up, offset); diff --git a/debian/patches-rt/0131-serial-8250-Switch-to-nbcon-console.patch b/debian/patches-rt/0131-serial-8250-Switch-to-nbcon-console.patch new file mode 100644 index 000000000..7ba577d9c --- /dev/null +++ b/debian/patches-rt/0131-serial-8250-Switch-to-nbcon-console.patch @@ -0,0 +1,335 @@ +From: John Ogness +Date: Wed, 13 Sep 2023 15:30:36 +0000 +Subject: [PATCH 131/134] serial: 8250: Switch to nbcon console +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Implement the necessary callbacks to switch the 8250 console driver +to perform as an nbcon console. + +Add implementations for the nbcon consoles (write_atomic, write_thread, +driver_enter, driver_exit) and add CON_NBCON to the initial flags. + +The legacy code is kept in order to easily switch back to legacy mode +by defining CONFIG_SERIAL_8250_LEGACY_CONSOLE. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/8250/8250_core.c | 42 +++++++++ + drivers/tty/serial/8250/8250_port.c | 156 +++++++++++++++++++++++++++++++++++- + include/linux/serial_8250.h | 6 + + 3 files changed, 201 insertions(+), 3 deletions(-) + +--- a/drivers/tty/serial/8250/8250_core.c ++++ b/drivers/tty/serial/8250/8250_core.c +@@ -592,6 +592,7 @@ serial8250_register_ports(struct uart_dr + + #ifdef CONFIG_SERIAL_8250_CONSOLE + ++#ifdef CONFIG_SERIAL_8250_LEGACY_CONSOLE + static void univ8250_console_write(struct console *co, const char *s, + unsigned int count) + { +@@ -599,6 +600,37 @@ static void univ8250_console_write(struc + + serial8250_console_write(up, s, count); + } ++#else ++static bool univ8250_console_write_atomic(struct console *co, ++ struct nbcon_write_context *wctxt) ++{ ++ struct uart_8250_port *up = &serial8250_ports[co->index]; ++ ++ return serial8250_console_write_atomic(up, wctxt); ++} ++ ++static bool univ8250_console_write_thread(struct console *co, ++ struct nbcon_write_context *wctxt) ++{ ++ struct uart_8250_port *up = &serial8250_ports[co->index]; ++ ++ return serial8250_console_write_thread(up, wctxt); ++} ++ ++static void univ8250_console_driver_enter(struct console *con, unsigned long *flags) ++{ ++ struct uart_port *up = &serial8250_ports[con->index].port; ++ ++ __uart_port_lock_irqsave(up, flags); ++} ++ ++static void univ8250_console_driver_exit(struct console *con, unsigned long flags) ++{ ++ struct uart_port *up = &serial8250_ports[con->index].port; ++ ++ __uart_port_unlock_irqrestore(up, flags); ++} ++#endif /* CONFIG_SERIAL_8250_LEGACY_CONSOLE */ + + static int univ8250_console_setup(struct console *co, char *options) + { +@@ -698,12 +730,20 @@ static int univ8250_console_match(struct + + static struct console univ8250_console = { + .name = "ttyS", ++#ifdef CONFIG_SERIAL_8250_LEGACY_CONSOLE + .write = univ8250_console_write, ++ .flags = CON_PRINTBUFFER | CON_ANYTIME, ++#else ++ .write_atomic = univ8250_console_write_atomic, ++ .write_thread = univ8250_console_write_thread, ++ .driver_enter = univ8250_console_driver_enter, ++ .driver_exit = univ8250_console_driver_exit, ++ .flags = CON_PRINTBUFFER | CON_ANYTIME | CON_NBCON, ++#endif + .device = uart_console_device, + .setup = univ8250_console_setup, + .exit = univ8250_console_exit, + .match = univ8250_console_match, +- .flags = CON_PRINTBUFFER | CON_ANYTIME, + .index = -1, + .data = &serial8250_reg, + }; +--- a/drivers/tty/serial/8250/8250_port.c ++++ b/drivers/tty/serial/8250/8250_port.c +@@ -557,6 +557,11 @@ static int serial8250_em485_init(struct + if (!p->em485) + return -ENOMEM; + ++#ifndef CONFIG_SERIAL_8250_LEGACY_CONSOLE ++ if (uart_console(&p->port)) ++ dev_warn(p->port.dev, "no atomic printing for rs485 consoles\n"); ++#endif ++ + hrtimer_init(&p->em485->stop_tx_timer, CLOCK_MONOTONIC, + HRTIMER_MODE_REL); + hrtimer_init(&p->em485->start_tx_timer, CLOCK_MONOTONIC, +@@ -709,7 +714,11 @@ static void serial8250_set_sleep(struct + serial8250_rpm_put(p); + } + +-static void serial8250_clear_IER(struct uart_8250_port *up) ++/* ++ * Only to be used by write_atomic() and the legacy write(), which do not ++ * require port lock. ++ */ ++static void __serial8250_clear_IER(struct uart_8250_port *up) + { + if (up->capabilities & UART_CAP_UUE) + serial_out(up, UART_IER, UART_IER_UUE); +@@ -717,6 +726,11 @@ static void serial8250_clear_IER(struct + serial_out(up, UART_IER, 0); + } + ++static inline void serial8250_clear_IER(struct uart_8250_port *up) ++{ ++ __serial8250_clear_IER(up); ++} ++ + #ifdef CONFIG_SERIAL_8250_RSA + /* + * Attempts to turn on the RSA FIFO. Returns zero on failure. +@@ -3328,6 +3342,11 @@ static void serial8250_console_putchar(s + + wait_for_xmitr(up, UART_LSR_THRE); + serial_port_out(port, UART_TX, ch); ++ ++ if (ch == '\n') ++ up->console_newline_needed = false; ++ else ++ up->console_newline_needed = true; + } + + /* +@@ -3356,6 +3375,7 @@ static void serial8250_console_restore(s + serial8250_out_MCR(up, up->mcr | UART_MCR_DTR | UART_MCR_RTS); + } + ++#ifdef CONFIG_SERIAL_8250_LEGACY_CONSOLE + /* + * Print a string to the serial port using the device FIFO + * +@@ -3414,7 +3434,7 @@ void serial8250_console_write(struct uar + * First save the IER then disable the interrupts + */ + ier = serial_port_in(port, UART_IER); +- serial8250_clear_IER(up); ++ __serial8250_clear_IER(up); + + /* check scratch reg to see if port powered off during system sleep */ + if (up->canary && (up->canary != serial_port_in(port, UART_SCR))) { +@@ -3480,6 +3500,135 @@ void serial8250_console_write(struct uar + if (locked) + uart_port_unlock_irqrestore(port, flags); + } ++#else ++bool serial8250_console_write_thread(struct uart_8250_port *up, ++ struct nbcon_write_context *wctxt) ++{ ++ struct uart_8250_em485 *em485 = up->em485; ++ struct uart_port *port = &up->port; ++ bool done = false; ++ unsigned int ier; ++ ++ touch_nmi_watchdog(); ++ ++ if (!nbcon_enter_unsafe(wctxt)) ++ return false; ++ ++ /* First save IER then disable the interrupts. */ ++ ier = serial_port_in(port, UART_IER); ++ serial8250_clear_IER(up); ++ ++ /* Check scratch reg if port powered off during system sleep. */ ++ if (up->canary && (up->canary != serial_port_in(port, UART_SCR))) { ++ serial8250_console_restore(up); ++ up->canary = 0; ++ } ++ ++ if (em485) { ++ if (em485->tx_stopped) ++ up->rs485_start_tx(up); ++ mdelay(port->rs485.delay_rts_before_send); ++ } ++ ++ if (nbcon_exit_unsafe(wctxt)) { ++ int len = READ_ONCE(wctxt->len); ++ int i; ++ ++ /* ++ * Write out the message. Toggle unsafe for each byte in order ++ * to give another (higher priority) context the opportunity ++ * for a friendly takeover. If such a takeover occurs, this ++ * context must reacquire ownership in order to perform final ++ * actions (such as re-enabling the interrupts). ++ * ++ * IMPORTANT: wctxt->outbuf and wctxt->len are no longer valid ++ * after a reacquire so writing the message must be ++ * aborted. ++ */ ++ for (i = 0; i < len; i++) { ++ if (!nbcon_enter_unsafe(wctxt)) { ++ nbcon_reacquire(wctxt); ++ break; ++ } ++ ++ uart_console_write(port, wctxt->outbuf + i, 1, serial8250_console_putchar); ++ ++ if (!nbcon_exit_unsafe(wctxt)) { ++ nbcon_reacquire(wctxt); ++ break; ++ } ++ } ++ done = (i == len); ++ } else { ++ nbcon_reacquire(wctxt); ++ } ++ ++ while (!nbcon_enter_unsafe(wctxt)) ++ nbcon_reacquire(wctxt); ++ ++ /* Finally, wait for transmitter to become empty and restore IER. */ ++ wait_for_xmitr(up, UART_LSR_BOTH_EMPTY); ++ if (em485) { ++ mdelay(port->rs485.delay_rts_after_send); ++ if (em485->tx_stopped) ++ up->rs485_stop_tx(up); ++ } ++ serial_port_out(port, UART_IER, ier); ++ ++ /* ++ * The receive handling will happen properly because the receive ready ++ * bit will still be set; it is not cleared on read. However, modem ++ * control will not, we must call it if we have saved something in the ++ * saved flags while processing with interrupts off. ++ */ ++ if (up->msr_saved_flags) ++ serial8250_modem_status(up); ++ ++ /* Success if no handover/takeover and message fully printed. */ ++ return (nbcon_exit_unsafe(wctxt) && done); ++} ++ ++bool serial8250_console_write_atomic(struct uart_8250_port *up, ++ struct nbcon_write_context *wctxt) ++{ ++ struct uart_port *port = &up->port; ++ unsigned int ier; ++ ++ /* Atomic console not supported for rs485 mode. */ ++ if (up->em485) ++ return false; ++ ++ touch_nmi_watchdog(); ++ ++ if (!nbcon_enter_unsafe(wctxt)) ++ return false; ++ ++ /* ++ * First save IER then disable the interrupts. The special variant to ++ * clear IER is used because atomic printing may occur without holding ++ * the port lock. ++ */ ++ ier = serial_port_in(port, UART_IER); ++ __serial8250_clear_IER(up); ++ ++ /* Check scratch reg if port powered off during system sleep. */ ++ if (up->canary && (up->canary != serial_port_in(port, UART_SCR))) { ++ serial8250_console_restore(up); ++ up->canary = 0; ++ } ++ ++ if (up->console_newline_needed) ++ uart_console_write(port, "\n", 1, serial8250_console_putchar); ++ uart_console_write(port, wctxt->outbuf, wctxt->len, serial8250_console_putchar); ++ ++ /* Finally, wait for transmitter to become empty and restore IER. */ ++ wait_for_xmitr(up, UART_LSR_BOTH_EMPTY); ++ serial_port_out(port, UART_IER, ier); ++ ++ /* Success if no handover/takeover. */ ++ return nbcon_exit_unsafe(wctxt); ++} ++#endif /* CONFIG_SERIAL_8250_LEGACY_CONSOLE */ + + static unsigned int probe_baud(struct uart_port *port) + { +@@ -3498,6 +3647,7 @@ static unsigned int probe_baud(struct ua + + int serial8250_console_setup(struct uart_port *port, char *options, bool probe) + { ++ struct uart_8250_port *up = up_to_u8250p(port); + int baud = 9600; + int bits = 8; + int parity = 'n'; +@@ -3507,6 +3657,8 @@ int serial8250_console_setup(struct uart + if (!port->iobase && !port->membase) + return -ENODEV; + ++ up->console_newline_needed = false; ++ + if (options) + uart_parse_options(options, &baud, &parity, &bits, &flow); + else if (probe) +--- a/include/linux/serial_8250.h ++++ b/include/linux/serial_8250.h +@@ -153,6 +153,8 @@ struct uart_8250_port { + #define MSR_SAVE_FLAGS UART_MSR_ANY_DELTA + unsigned char msr_saved_flags; + ++ bool console_newline_needed; ++ + struct uart_8250_dma *dma; + const struct uart_8250_ops *ops; + +@@ -204,6 +206,10 @@ void serial8250_init_port(struct uart_82 + void serial8250_set_defaults(struct uart_8250_port *up); + void serial8250_console_write(struct uart_8250_port *up, const char *s, + unsigned int count); ++bool serial8250_console_write_atomic(struct uart_8250_port *up, ++ struct nbcon_write_context *wctxt); ++bool serial8250_console_write_thread(struct uart_8250_port *up, ++ struct nbcon_write_context *wctxt); + int serial8250_console_setup(struct uart_port *port, char *options, bool probe); + int serial8250_console_exit(struct uart_port *port); + diff --git a/debian/patches-rt/0132-printk-Add-kthread-for-all-legacy-consoles.patch b/debian/patches-rt/0132-printk-Add-kthread-for-all-legacy-consoles.patch new file mode 100644 index 000000000..7c46be713 --- /dev/null +++ b/debian/patches-rt/0132-printk-Add-kthread-for-all-legacy-consoles.patch @@ -0,0 +1,422 @@ +From: John Ogness +Date: Fri, 22 Sep 2023 17:35:04 +0000 +Subject: [PATCH 132/134] printk: Add kthread for all legacy consoles +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +The write callback of legacy consoles make use of spinlocks. +This is not permitted with PREEMPT_RT in atomic contexts. + +Create a new kthread to handle printing of all the legacy +consoles (and nbcon consoles if boot consoles are registered). + +Since the consoles are printing in a task context, it is no +longer appropriate to support the legacy handover mechanism. + +These changes exist only for CONFIG_PREEMPT_RT. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/internal.h | 1 + kernel/printk/nbcon.c | 18 ++- + kernel/printk/printk.c | 237 +++++++++++++++++++++++++++++++++++++++-------- + 3 files changed, 210 insertions(+), 46 deletions(-) + +--- a/kernel/printk/internal.h ++++ b/kernel/printk/internal.h +@@ -95,6 +95,7 @@ void nbcon_atomic_flush_all(void); + bool nbcon_atomic_emit_next_record(struct console *con, bool *handover, int cookie); + void nbcon_kthread_create(struct console *con); + void nbcon_wake_threads(void); ++void nbcon_legacy_kthread_create(void); + + /* + * Check if the given console is currently capable and allowed to print +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -1247,9 +1247,11 @@ bool nbcon_atomic_emit_next_record(struc + *handover = false; + + /* Use the same locking order as console_emit_next_record(). */ +- printk_safe_enter_irqsave(flags); +- console_lock_spinning_enable(); +- stop_critical_timings(); ++ if (!IS_ENABLED(CONFIG_PREEMPT_RT)) { ++ printk_safe_enter_irqsave(flags); ++ console_lock_spinning_enable(); ++ stop_critical_timings(); ++ } + + con->driver_enter(con, &driver_flags); + cant_migrate(); +@@ -1261,9 +1263,11 @@ bool nbcon_atomic_emit_next_record(struc + + con->driver_exit(con, driver_flags); + +- start_critical_timings(); +- *handover = console_lock_spinning_disable_and_check(cookie); +- printk_safe_exit_irqrestore(flags); ++ if (!IS_ENABLED(CONFIG_PREEMPT_RT)) { ++ start_critical_timings(); ++ *handover = console_lock_spinning_disable_and_check(cookie); ++ printk_safe_exit_irqrestore(flags); ++ } + + return progress; + } +@@ -1469,6 +1473,8 @@ static int __init printk_setup_threads(v + printk_threads_enabled = true; + for_each_console(con) + nbcon_kthread_create(con); ++ if (IS_ENABLED(CONFIG_PREEMPT_RT) && printing_via_unlock) ++ nbcon_legacy_kthread_create(); + console_list_unlock(); + return 0; + } +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -487,6 +487,9 @@ bool have_boot_console; + + #ifdef CONFIG_PRINTK + DECLARE_WAIT_QUEUE_HEAD(log_wait); ++ ++static DECLARE_WAIT_QUEUE_HEAD(legacy_wait); ++ + /* All 3 protected by @syslog_lock. */ + /* the next printk record to read by syslog(READ) or /proc/kmsg */ + static u64 syslog_seq; +@@ -2345,7 +2348,8 @@ asmlinkage int vprintk_emit(int facility + const struct dev_printk_info *dev_info, + const char *fmt, va_list args) + { +- bool do_trylock_unlock = printing_via_unlock; ++ bool do_trylock_unlock = printing_via_unlock && ++ !IS_ENABLED(CONFIG_PREEMPT_RT); + int printed_len; + + /* Suppress unimportant messages after panic happens */ +@@ -2473,6 +2477,14 @@ EXPORT_SYMBOL(_printk); + static bool pr_flush(int timeout_ms, bool reset_on_progress); + static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progress); + ++static struct task_struct *nbcon_legacy_kthread; ++ ++static inline void wake_up_legacy_kthread(void) ++{ ++ if (nbcon_legacy_kthread) ++ wake_up_interruptible(&legacy_wait); ++} ++ + #else /* CONFIG_PRINTK */ + + #define printk_time false +@@ -2486,6 +2498,8 @@ static u64 syslog_seq; + static bool pr_flush(int timeout_ms, bool reset_on_progress) { return true; } + static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progress) { return true; } + ++static inline void nbcon_legacy_kthread_create(void) { } ++static inline void wake_up_legacy_kthread(void) { } + #endif /* CONFIG_PRINTK */ + + #ifdef CONFIG_EARLY_PRINTK +@@ -2723,6 +2737,8 @@ void resume_console(void) + } + console_srcu_read_unlock(cookie); + ++ wake_up_legacy_kthread(); ++ + pr_flush(1000, true); + } + +@@ -2737,7 +2753,8 @@ void resume_console(void) + */ + static int console_cpu_notify(unsigned int cpu) + { +- if (!cpuhp_tasks_frozen && printing_via_unlock) { ++ if (!cpuhp_tasks_frozen && printing_via_unlock && ++ !IS_ENABLED(CONFIG_PREEMPT_RT)) { + /* If trylock fails, someone else is doing the printing */ + if (console_trylock()) + console_unlock(); +@@ -2962,31 +2979,43 @@ static bool console_emit_next_record(str + con->dropped = 0; + } + +- /* +- * While actively printing out messages, if another printk() +- * were to occur on another CPU, it may wait for this one to +- * finish. This task can not be preempted if there is a +- * waiter waiting to take over. +- * +- * Interrupts are disabled because the hand over to a waiter +- * must not be interrupted until the hand over is completed +- * (@console_waiter is cleared). +- */ +- printk_safe_enter_irqsave(flags); +- console_lock_spinning_enable(); ++ /* Write everything out to the hardware. */ + +- /* Do not trace print latency. */ +- stop_critical_timings(); ++ if (IS_ENABLED(CONFIG_PREEMPT_RT)) { ++ /* ++ * On PREEMPT_RT this function is either in a thread or ++ * panic context. So there is no need for concern about ++ * printk reentrance or handovers. ++ */ + +- /* Write everything out to the hardware. */ +- con->write(con, outbuf, pmsg.outbuf_len); ++ con->write(con, outbuf, pmsg.outbuf_len); ++ con->seq = pmsg.seq + 1; ++ } else { ++ /* ++ * While actively printing out messages, if another printk() ++ * were to occur on another CPU, it may wait for this one to ++ * finish. This task can not be preempted if there is a ++ * waiter waiting to take over. ++ * ++ * Interrupts are disabled because the hand over to a waiter ++ * must not be interrupted until the hand over is completed ++ * (@console_waiter is cleared). ++ */ ++ printk_safe_enter_irqsave(flags); ++ console_lock_spinning_enable(); + +- start_critical_timings(); ++ /* Do not trace print latency. */ ++ stop_critical_timings(); + +- con->seq = pmsg.seq + 1; ++ con->write(con, outbuf, pmsg.outbuf_len); + +- *handover = console_lock_spinning_disable_and_check(cookie); +- printk_safe_exit_irqrestore(flags); ++ start_critical_timings(); ++ ++ con->seq = pmsg.seq + 1; ++ ++ *handover = console_lock_spinning_disable_and_check(cookie); ++ printk_safe_exit_irqrestore(flags); ++ } + skip: + return true; + } +@@ -3096,19 +3125,7 @@ static bool console_flush_all(bool do_co + return false; + } + +-/** +- * console_unlock - unblock the console subsystem from printing +- * +- * Releases the console_lock which the caller holds to block printing of +- * the console subsystem. +- * +- * While the console_lock was held, console output may have been buffered +- * by printk(). If this is the case, console_unlock(); emits +- * the output prior to releasing the lock. +- * +- * console_unlock(); may be called from any context. +- */ +-void console_unlock(void) ++static void console_flush_and_unlock(void) + { + bool do_cond_resched; + bool handover; +@@ -3152,6 +3169,32 @@ void console_unlock(void) + */ + } while (prb_read_valid(prb, next_seq, NULL) && console_trylock()); + } ++ ++/** ++ * console_unlock - unblock the console subsystem from printing ++ * ++ * Releases the console_lock which the caller holds to block printing of ++ * the console subsystem. ++ * ++ * While the console_lock was held, console output may have been buffered ++ * by printk(). If this is the case, console_unlock(); emits ++ * the output prior to releasing the lock. ++ * ++ * console_unlock(); may be called from any context. ++ */ ++void console_unlock(void) ++{ ++ /* ++ * PREEMPT_RT relies on kthread and atomic consoles for printing. ++ * It never attempts to print from console_unlock(). ++ */ ++ if (IS_ENABLED(CONFIG_PREEMPT_RT)) { ++ __console_unlock(); ++ return; ++ } ++ ++ console_flush_and_unlock(); ++} + EXPORT_SYMBOL(console_unlock); + + /** +@@ -3361,11 +3404,106 @@ void console_start(struct console *conso + + if (flags & CON_NBCON) + nbcon_kthread_wake(console); ++ else ++ wake_up_legacy_kthread(); + + __pr_flush(console, 1000, true); + } + EXPORT_SYMBOL(console_start); + ++#ifdef CONFIG_PRINTK ++static bool printer_should_wake(void) ++{ ++ bool available = false; ++ struct console *con; ++ int cookie; ++ ++ if (kthread_should_stop()) ++ return true; ++ ++ cookie = console_srcu_read_lock(); ++ for_each_console_srcu(con) { ++ short flags = console_srcu_read_flags(con); ++ u64 printk_seq; ++ ++ /* ++ * The legacy printer thread is only for legacy consoles, ++ * unless the nbcon console has no kthread printer. ++ */ ++ if ((flags & CON_NBCON) && con->kthread) ++ continue; ++ ++ if (!console_is_usable(con, flags, true)) ++ continue; ++ ++ if (flags & CON_NBCON) { ++ printk_seq = nbcon_seq_read(con); ++ } else { ++ /* ++ * It is safe to read @seq because only this ++ * thread context updates @seq. ++ */ ++ printk_seq = con->seq; ++ } ++ ++ if (prb_read_valid(prb, printk_seq, NULL)) { ++ available = true; ++ break; ++ } ++ } ++ console_srcu_read_unlock(cookie); ++ ++ return available; ++} ++ ++static int nbcon_legacy_kthread_func(void *unused) ++{ ++ int error; ++ ++ for (;;) { ++ error = wait_event_interruptible(legacy_wait, printer_should_wake()); ++ ++ if (kthread_should_stop()) ++ break; ++ ++ if (error) ++ continue; ++ ++ console_lock(); ++ console_flush_and_unlock(); ++ } ++ ++ return 0; ++} ++ ++void nbcon_legacy_kthread_create(void) ++{ ++ struct task_struct *kt; ++ ++ lockdep_assert_held(&console_mutex); ++ ++ if (!IS_ENABLED(CONFIG_PREEMPT_RT)) ++ return; ++ ++ if (!printk_threads_enabled || nbcon_legacy_kthread) ++ return; ++ ++ kt = kthread_run(nbcon_legacy_kthread_func, NULL, "pr/legacy"); ++ if (IS_ERR(kt)) { ++ pr_err("unable to start legacy printing thread\n"); ++ return; ++ } ++ ++ nbcon_legacy_kthread = kt; ++ ++ /* ++ * It is important that console printing threads are scheduled ++ * shortly after a printk call and with generous runtime budgets. ++ */ ++ sched_set_normal(nbcon_legacy_kthread, -20); ++} ++#endif /* CONFIG_PRINTK */ ++ + static int __read_mostly keep_bootcon; + + static int __init keep_bootcon_setup(char *str) +@@ -3632,6 +3770,7 @@ void register_console(struct console *ne + nbcon_init(newcon); + } else { + have_legacy_console = true; ++ nbcon_legacy_kthread_create(); + } + + if (newcon->flags & CON_BOOT) +@@ -3770,6 +3909,13 @@ static int unregister_console_locked(str + nbcon_kthread_create(c); + } + ++#ifdef CONFIG_PRINTK ++ if (!printing_via_unlock && nbcon_legacy_kthread) { ++ kthread_stop(nbcon_legacy_kthread); ++ nbcon_legacy_kthread = NULL; ++ } ++#endif ++ + return res; + } + +@@ -3929,8 +4075,12 @@ static bool __pr_flush(struct console *c + + seq = prb_next_reserve_seq(prb); + +- /* Flush the consoles so that records up to @seq are printed. */ +- if (printing_via_unlock) { ++ /* ++ * Flush the consoles so that records up to @seq are printed. ++ * Otherwise this function will just wait for the threaded printers ++ * to print up to @seq. ++ */ ++ if (printing_via_unlock && !IS_ENABLED(CONFIG_PREEMPT_RT)) { + console_lock(); + console_unlock(); + } +@@ -4038,9 +4188,16 @@ static void wake_up_klogd_work_func(stru + int pending = this_cpu_xchg(printk_pending, 0); + + if (pending & PRINTK_PENDING_OUTPUT) { +- /* If trylock fails, someone else is doing the printing */ +- if (console_trylock()) +- console_unlock(); ++ if (IS_ENABLED(CONFIG_PREEMPT_RT)) { ++ wake_up_interruptible(&legacy_wait); ++ } else { ++ /* ++ * If trylock fails, some other context ++ * will do the printing. ++ */ ++ if (console_trylock()) ++ console_unlock(); ++ } + } + + if (pending & PRINTK_PENDING_WAKEUP) diff --git a/debian/patches-rt/0133-serial-8250-revert-drop-lockdep-annotation-from-seri.patch b/debian/patches-rt/0133-serial-8250-revert-drop-lockdep-annotation-from-seri.patch new file mode 100644 index 000000000..c9eba0a73 --- /dev/null +++ b/debian/patches-rt/0133-serial-8250-revert-drop-lockdep-annotation-from-seri.patch @@ -0,0 +1,29 @@ +From: John Ogness +Date: Mon, 2 Oct 2023 15:30:43 +0000 +Subject: [PATCH 133/134] serial: 8250: revert "drop lockdep annotation from + serial8250_clear_IER()" +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +The 8250 driver no longer depends on @oops_in_progress and +will no longer violate the port->lock locking constraints. + +This reverts commit 3d9e6f556e235ddcdc9f73600fdd46fe1736b090. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/tty/serial/8250/8250_port.c | 3 +++ + 1 file changed, 3 insertions(+) + +--- a/drivers/tty/serial/8250/8250_port.c ++++ b/drivers/tty/serial/8250/8250_port.c +@@ -728,6 +728,9 @@ static void __serial8250_clear_IER(struc + + static inline void serial8250_clear_IER(struct uart_8250_port *up) + { ++ /* Port locked to synchronize UART_IER access against the console. */ ++ lockdep_assert_held_once(&up->port.lock); ++ + __serial8250_clear_IER(up); + } + diff --git a/debian/patches-rt/0134-printk-Avoid-false-positive-lockdep-report-for-legac.patch b/debian/patches-rt/0134-printk-Avoid-false-positive-lockdep-report-for-legac.patch new file mode 100644 index 000000000..225e8db69 --- /dev/null +++ b/debian/patches-rt/0134-printk-Avoid-false-positive-lockdep-report-for-legac.patch @@ -0,0 +1,64 @@ +From: John Ogness +Date: Mon, 11 Dec 2023 09:34:16 +0000 +Subject: [PATCH 134/134] printk: Avoid false positive lockdep report for + legacy driver. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +printk may invoke the legacy console driver from atomic context. This leads to +a lockdep splat because the console driver will acquire a sleeping lock and the +caller may also hold a spinning lock. This is noticed by lockdep on !PREEMPT_RT +configurations because it will also lead to a problem on PREEMPT_RT. + +On PREEMPT_RT the atomic path is always avoided and the console driver is +always invoked from a dedicated thread. Thus the lockdep splat is a false +positive. + +Override the lock-context before invoking the console driver. + +Signed-off-by: John Ogness +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/printk/printk.c | 9 ++++++++- + 1 file changed, 8 insertions(+), 1 deletion(-) + +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -2817,6 +2817,8 @@ static void __console_unlock(void) + up_console_sem(); + } + ++static DEFINE_WAIT_OVERRIDE_MAP(printk_legacy_map, LD_WAIT_SLEEP); ++ + #ifdef CONFIG_PRINTK + + /* +@@ -2985,7 +2987,7 @@ static bool console_emit_next_record(str + /* + * On PREEMPT_RT this function is either in a thread or + * panic context. So there is no need for concern about +- * printk reentrance or handovers. ++ * printk reentrance, handovers, or lockdep complaints. + */ + + con->write(con, outbuf, pmsg.outbuf_len); +@@ -3007,7 +3009,9 @@ static bool console_emit_next_record(str + /* Do not trace print latency. */ + stop_critical_timings(); + ++ lock_map_acquire_try(&printk_legacy_map); + con->write(con, outbuf, pmsg.outbuf_len); ++ lock_map_release(&printk_legacy_map); + + start_critical_timings(); + +@@ -3084,7 +3088,10 @@ static bool console_flush_all(bool do_co + any_usable = true; + + if (flags & CON_NBCON) { ++ ++ lock_map_acquire_try(&printk_legacy_map); + progress = nbcon_atomic_emit_next_record(con, handover, cookie); ++ lock_map_release(&printk_legacy_map); + + printk_seq = nbcon_seq_read(con); + } else { diff --git a/debian/patches-rt/ARM64__Allow_to_enable_RT.patch b/debian/patches-rt/ARM64__Allow_to_enable_RT.patch new file mode 100644 index 000000000..3657ef870 --- /dev/null +++ b/debian/patches-rt/ARM64__Allow_to_enable_RT.patch @@ -0,0 +1,27 @@ +Subject: ARM64: Allow to enable RT +From: Sebastian Andrzej Siewior +Date: Fri Oct 11 13:14:35 2019 +0200 +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +From: Sebastian Andrzej Siewior + +Allow to select RT. + +Signed-off-by: Sebastian Andrzej Siewior +Signed-off-by: Thomas Gleixner + + +--- + arch/arm64/Kconfig | 1 + + 1 file changed, 1 insertion(+) +--- +--- a/arch/arm64/Kconfig ++++ b/arch/arm64/Kconfig +@@ -97,6 +97,7 @@ config ARM64 + select ARCH_SUPPORTS_NUMA_BALANCING + select ARCH_SUPPORTS_PAGE_TABLE_CHECK + select ARCH_SUPPORTS_PER_VMA_LOCK ++ select ARCH_SUPPORTS_RT + select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH + select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT + select ARCH_WANT_DEFAULT_BPF_JIT diff --git a/debian/patches-rt/ARM__Allow_to_enable_RT.patch b/debian/patches-rt/ARM__Allow_to_enable_RT.patch new file mode 100644 index 000000000..902eca18c --- /dev/null +++ b/debian/patches-rt/ARM__Allow_to_enable_RT.patch @@ -0,0 +1,35 @@ +Subject: ARM: Allow to enable RT +From: Sebastian Andrzej Siewior +Date: Fri Oct 11 13:14:29 2019 +0200 +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +From: Sebastian Andrzej Siewior + +Allow to select RT. + +Signed-off-by: Sebastian Andrzej Siewior +Signed-off-by: Thomas Gleixner + + +--- + arch/arm/Kconfig | 2 ++ + 1 file changed, 2 insertions(+) +--- +--- a/arch/arm/Kconfig ++++ b/arch/arm/Kconfig +@@ -34,6 +34,7 @@ config ARM + select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7 + select ARCH_SUPPORTS_ATOMIC_RMW + select ARCH_SUPPORTS_HUGETLBFS if ARM_LPAE ++ select ARCH_SUPPORTS_RT if HAVE_POSIX_CPU_TIMERS_TASK_WORK + select ARCH_USE_BUILTIN_BSWAP + select ARCH_USE_CMPXCHG_LOCKREF + select ARCH_USE_MEMTEST +@@ -118,6 +119,7 @@ config ARM + select HAVE_PERF_EVENTS + select HAVE_PERF_REGS + select HAVE_PERF_USER_STACK_DUMP ++ select HAVE_POSIX_CPU_TIMERS_TASK_WORK if !KVM + select MMU_GATHER_RCU_TABLE_FREE if SMP && ARM_LPAE + select HAVE_REGS_AND_STACK_ACCESS_API + select HAVE_RSEQ diff --git a/debian/patches-rt/ARM__enable_irq_in_translation_section_permission_fault_handlers.patch b/debian/patches-rt/ARM__enable_irq_in_translation_section_permission_fault_handlers.patch new file mode 100644 index 000000000..ce42fd3a2 --- /dev/null +++ b/debian/patches-rt/ARM__enable_irq_in_translation_section_permission_fault_handlers.patch @@ -0,0 +1,91 @@ +Subject: ARM: enable irq in translation/section permission fault handlers +From: Yadi.hu +Date: Wed Dec 10 10:32:09 2014 +0800 +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +From: Yadi.hu + +Probably happens on all ARM, with +CONFIG_PREEMPT_RT +CONFIG_DEBUG_ATOMIC_SLEEP + +This simple program.... + +int main() { + *((char*)0xc0001000) = 0; +}; + +[ 512.742724] BUG: sleeping function called from invalid context at kernel/rtmutex.c:658 +[ 512.743000] in_atomic(): 0, irqs_disabled(): 128, pid: 994, name: a +[ 512.743217] INFO: lockdep is turned off. +[ 512.743360] irq event stamp: 0 +[ 512.743482] hardirqs last enabled at (0): [< (null)>] (null) +[ 512.743714] hardirqs last disabled at (0): [] copy_process+0x3b0/0x11c0 +[ 512.744013] softirqs last enabled at (0): [] copy_process+0x3b0/0x11c0 +[ 512.744303] softirqs last disabled at (0): [< (null)>] (null) +[ 512.744631] [] (unwind_backtrace+0x0/0x104) +[ 512.745001] [] (dump_stack+0x20/0x24) +[ 512.745355] [] (__might_sleep+0x1dc/0x1e0) +[ 512.745717] [] (rt_spin_lock+0x34/0x6c) +[ 512.746073] [] (do_force_sig_info+0x34/0xf0) +[ 512.746457] [] (force_sig_info+0x18/0x1c) +[ 512.746829] [] (__do_user_fault+0x9c/0xd8) +[ 512.747185] [] (do_bad_area+0x7c/0x94) +[ 512.747536] [] (do_sect_fault+0x40/0x48) +[ 512.747898] [] (do_DataAbort+0x40/0xa0) +[ 512.748181] Exception stack(0xecaa1fb0 to 0xecaa1ff8) + +Oxc0000000 belongs to kernel address space, user task can not be +allowed to access it. For above condition, correct result is that +test case should receive a “segment fault” and exits but not stacks. + +the root cause is commit 02fe2845d6a8 ("avoid enabling interrupts in +prefetch/data abort handlers"),it deletes irq enable block in Data +abort assemble code and move them into page/breakpiont/alignment fault +handlers instead. But author does not enable irq in translation/section +permission fault handlers. ARM disables irq when it enters exception/ +interrupt mode, if kernel doesn't enable irq, it would be still disabled +during translation/section permission fault. + +We see the above splat because do_force_sig_info is still called with +IRQs off, and that code eventually does a: + + spin_lock_irqsave(&t->sighand->siglock, flags); + +As this is architecture independent code, and we've not seen any other +need for other arch to have the siglock converted to raw lock, we can +conclude that we should enable irq for ARM translation/section +permission exception. + + +Signed-off-by: Yadi.hu +Signed-off-by: Sebastian Andrzej Siewior +Signed-off-by: Thomas Gleixner + + +--- + arch/arm/mm/fault.c | 6 ++++++ + 1 file changed, 6 insertions(+) +--- +--- a/arch/arm/mm/fault.c ++++ b/arch/arm/mm/fault.c +@@ -404,6 +404,9 @@ do_translation_fault(unsigned long addr, + if (addr < TASK_SIZE) + return do_page_fault(addr, fsr, regs); + ++ if (interrupts_enabled(regs)) ++ local_irq_enable(); ++ + if (user_mode(regs)) + goto bad_area; + +@@ -474,6 +477,9 @@ do_translation_fault(unsigned long addr, + static int + do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs) + { ++ if (interrupts_enabled(regs)) ++ local_irq_enable(); ++ + do_bad_area(addr, fsr, regs); + return 0; + } diff --git a/debian/patches-rt/Add_localversion_for_-RT_release.patch b/debian/patches-rt/Add_localversion_for_-RT_release.patch new file mode 100644 index 000000000..55db77eff --- /dev/null +++ b/debian/patches-rt/Add_localversion_for_-RT_release.patch @@ -0,0 +1,19 @@ +Subject: Add localversion for -RT release +From: Thomas Gleixner +Date: Fri Jul 8 20:25:16 2011 +0200 +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +From: Thomas Gleixner + +Signed-off-by: Thomas Gleixner + + +--- + localversion-rt | 1 + + 1 file changed, 1 insertion(+) + create mode 100644 localversion-rt +--- +--- /dev/null ++++ b/localversion-rt +@@ -0,0 +1 @@ ++-rt18 diff --git a/debian/patches-rt/POWERPC__Allow_to_enable_RT.patch b/debian/patches-rt/POWERPC__Allow_to_enable_RT.patch new file mode 100644 index 000000000..797e2084b --- /dev/null +++ b/debian/patches-rt/POWERPC__Allow_to_enable_RT.patch @@ -0,0 +1,35 @@ +Subject: POWERPC: Allow to enable RT +From: Sebastian Andrzej Siewior +Date: Fri Oct 11 13:14:41 2019 +0200 +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +From: Sebastian Andrzej Siewior + +Allow to select RT. + +Signed-off-by: Sebastian Andrzej Siewior +Signed-off-by: Thomas Gleixner + + +--- + arch/powerpc/Kconfig | 2 ++ + 1 file changed, 2 insertions(+) +--- +--- a/arch/powerpc/Kconfig ++++ b/arch/powerpc/Kconfig +@@ -166,6 +166,7 @@ config PPC + select ARCH_STACKWALK + select ARCH_SUPPORTS_ATOMIC_RMW + select ARCH_SUPPORTS_DEBUG_PAGEALLOC if PPC_BOOK3S || PPC_8xx || 40x ++ select ARCH_SUPPORTS_RT if HAVE_POSIX_CPU_TIMERS_TASK_WORK + select ARCH_USE_BUILTIN_BSWAP + select ARCH_USE_CMPXCHG_LOCKREF if PPC64 + select ARCH_USE_MEMTEST +@@ -268,6 +269,7 @@ config PPC + select HAVE_PERF_USER_STACK_DUMP + select HAVE_REGS_AND_STACK_ACCESS_API + select HAVE_RELIABLE_STACKTRACE ++ select HAVE_POSIX_CPU_TIMERS_TASK_WORK if !KVM + select HAVE_RSEQ + select HAVE_SETUP_PER_CPU_AREA if PPC64 + select HAVE_SOFTIRQ_ON_OWN_STACK diff --git a/debian/patches-rt/PREEMPT_AUTO.patch b/debian/patches-rt/PREEMPT_AUTO.patch new file mode 100644 index 000000000..859dadc20 --- /dev/null +++ b/debian/patches-rt/PREEMPT_AUTO.patch @@ -0,0 +1,779 @@ +From: Thomas Gleixner +Date: Sat, 23 Sep 2023 03:11:05 +0200 +Subject: [PATCH] sched: define TIF_ALLOW_RESCHED +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +On Fri, Sep 22 2023 at 00:55, Thomas Gleixner wrote: +> On Thu, Sep 21 2023 at 09:00, Linus Torvalds wrote: +>> That said - I think as a proof of concept and "look, with this we get +>> the expected scheduling event counts", that patch is perfect. I think +>> you more than proved the concept. +> +> There is certainly quite some analyis work to do to make this a one to +> one replacement. +> +> With a handful of benchmarks the PoC (tweaked with some obvious fixes) +> is pretty much on par with the current mainline variants (NONE/FULL), +> but the memtier benchmark makes a massive dent. +> +> It sports a whopping 10% regression with the LAZY mode versus the mainline +> NONE model. Non-LAZY and FULL behave unsurprisingly in the same way. +> +> That benchmark is really sensitive to the preemption model. With current +> mainline (DYNAMIC_PREEMPT enabled) the preempt=FULL model has ~20% +> performance drop versus preempt=NONE. + +That 20% was a tired pilot error. The real number is in the 5% ballpark. + +> I have no clue what's going on there yet, but that shows that there is +> obviously quite some work ahead to get this sorted. + +It took some head scratching to figure that out. The initial fix broke +the handling of the hog issue, i.e. the problem that Ankur tried to +solve, but I hacked up a "solution" for that too. + +With that the memtier benchmark is roughly back to the mainline numbers, +but my throughput benchmark know how is pretty close to zero, so that +should be looked at by people who actually understand these things. + +Likewise the hog prevention is just at the PoC level and clearly beyond +my knowledge of scheduler details: It unconditionally forces a +reschedule when the looping task is not responding to a lazy reschedule +request before the next tick. IOW it forces a reschedule on the second +tick, which is obviously different from the cond_resched()/might_sleep() +behaviour. + +The changes vs. the original PoC aside of the bug and thinko fixes: + + 1) A hack to utilize the TRACE_FLAG_IRQS_NOSUPPORT flag to trace the + lazy preempt bit as the trace_entry::flags field is full already. + + That obviously breaks the tracer ABI, but if we go there then + this needs to be fixed. Steven? + + 2) debugfs file to validate that loops can be force preempted w/o + cond_resched() + + The usage is: + + # taskset -c 1 bash + # echo 1 > /sys/kernel/debug/sched/hog & + # echo 1 > /sys/kernel/debug/sched/hog & + # echo 1 > /sys/kernel/debug/sched/hog & + + top shows ~33% CPU for each of the hogs and tracing confirms that + the crude hack in the scheduler tick works: + + bash-4559 [001] dlh2. 2253.331202: resched_curr <-__update_curr + bash-4560 [001] dlh2. 2253.340199: resched_curr <-__update_curr + bash-4561 [001] dlh2. 2253.346199: resched_curr <-__update_curr + bash-4559 [001] dlh2. 2253.353199: resched_curr <-__update_curr + bash-4561 [001] dlh2. 2253.358199: resched_curr <-__update_curr + bash-4560 [001] dlh2. 2253.370202: resched_curr <-__update_curr + bash-4559 [001] dlh2. 2253.378198: resched_curr <-__update_curr + bash-4561 [001] dlh2. 2253.389199: resched_curr <-__update_curr + + The 'l' instead of the usual 'N' reflects that the lazy resched + bit is set. That makes __update_curr() invoke resched_curr() + instead of the lazy variant. resched_curr() sets TIF_NEED_RESCHED + and folds it into preempt_count so that preemption happens at the + next possible point, i.e. either in return from interrupt or at + the next preempt_enable(). + +That's as much as I wanted to demonstrate and I'm not going to spend +more cycles on it as I have already too many other things on flight and +the resulting scheduler woes are clearly outside of my expertice. + +Though definitely I'm putting a permanent NAK in place for any attempts +to duct tape the preempt=NONE model any further by sprinkling more +cond*() and whatever warts around. + +Thanks, + + tglx + +[tglx: s@CONFIG_PREEMPT_AUTO@CONFIG_PREEMPT_BUILD_AUTO@ ] + +Link: https://lore.kernel.org/all/87jzshhexi.ffs@tglx/ +Signed-off-by: Thomas Gleixner +Signed-off-by: Sebastian Andrzej Siewior +--- + arch/x86/Kconfig | 1 + arch/x86/include/asm/thread_info.h | 6 ++-- + drivers/acpi/processor_idle.c | 2 - + include/linux/entry-common.h | 2 - + include/linux/entry-kvm.h | 2 - + include/linux/sched.h | 12 +++++--- + include/linux/sched/idle.h | 8 ++--- + include/linux/thread_info.h | 24 +++++++++++++++++ + include/linux/trace_events.h | 8 ++--- + kernel/Kconfig.preempt | 17 +++++++++++- + kernel/entry/common.c | 4 +- + kernel/entry/kvm.c | 2 - + kernel/sched/core.c | 50 +++++++++++++++++++++++++------------ + kernel/sched/debug.c | 19 ++++++++++++++ + kernel/sched/fair.c | 46 ++++++++++++++++++++++------------ + kernel/sched/features.h | 2 + + kernel/sched/idle.c | 3 -- + kernel/sched/sched.h | 1 + kernel/trace/trace.c | 2 + + kernel/trace/trace_output.c | 16 ++++++++++- + 20 files changed, 171 insertions(+), 56 deletions(-) + +--- a/arch/x86/Kconfig ++++ b/arch/x86/Kconfig +@@ -272,6 +272,7 @@ config X86 + select HAVE_STATIC_CALL + select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL + select HAVE_PREEMPT_DYNAMIC_CALL ++ select HAVE_PREEMPT_AUTO + select HAVE_RSEQ + select HAVE_RUST if X86_64 + select HAVE_SYSCALL_TRACEPOINTS +--- a/arch/x86/include/asm/thread_info.h ++++ b/arch/x86/include/asm/thread_info.h +@@ -81,8 +81,9 @@ struct thread_info { + #define TIF_NOTIFY_RESUME 1 /* callback before returning to user */ + #define TIF_SIGPENDING 2 /* signal pending */ + #define TIF_NEED_RESCHED 3 /* rescheduling necessary */ +-#define TIF_SINGLESTEP 4 /* reenable singlestep on user return*/ +-#define TIF_SSBD 5 /* Speculative store bypass disable */ ++#define TIF_ARCH_RESCHED_LAZY 4 /* Lazy rescheduling */ ++#define TIF_SINGLESTEP 5 /* reenable singlestep on user return*/ ++#define TIF_SSBD 6 /* Speculative store bypass disable */ + #define TIF_SPEC_IB 9 /* Indirect branch speculation mitigation */ + #define TIF_SPEC_L1D_FLUSH 10 /* Flush L1D on mm switches (processes) */ + #define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */ +@@ -104,6 +105,7 @@ struct thread_info { + #define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME) + #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) + #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) ++#define _TIF_ARCH_RESCHED_LAZY (1 << TIF_ARCH_RESCHED_LAZY) + #define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP) + #define _TIF_SSBD (1 << TIF_SSBD) + #define _TIF_SPEC_IB (1 << TIF_SPEC_IB) +--- a/drivers/acpi/processor_idle.c ++++ b/drivers/acpi/processor_idle.c +@@ -108,7 +108,7 @@ static const struct dmi_system_id proces + */ + static void __cpuidle acpi_safe_halt(void) + { +- if (!tif_need_resched()) { ++ if (!need_resched()) { + raw_safe_halt(); + raw_local_irq_disable(); + } +--- a/include/linux/entry-common.h ++++ b/include/linux/entry-common.h +@@ -60,7 +60,7 @@ + #define EXIT_TO_USER_MODE_WORK \ + (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_UPROBE | \ + _TIF_NEED_RESCHED | _TIF_PATCH_PENDING | _TIF_NOTIFY_SIGNAL | \ +- ARCH_EXIT_TO_USER_MODE_WORK) ++ _TIF_NEED_RESCHED_LAZY | ARCH_EXIT_TO_USER_MODE_WORK) + + /** + * arch_enter_from_user_mode - Architecture specific sanity check for user mode regs +--- a/include/linux/entry-kvm.h ++++ b/include/linux/entry-kvm.h +@@ -18,7 +18,7 @@ + + #define XFER_TO_GUEST_MODE_WORK \ + (_TIF_NEED_RESCHED | _TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL | \ +- _TIF_NOTIFY_RESUME | ARCH_XFER_TO_GUEST_MODE_WORK) ++ _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED_LAZY | ARCH_XFER_TO_GUEST_MODE_WORK) + + struct kvm_vcpu; + +--- a/include/linux/sched.h ++++ b/include/linux/sched.h +@@ -2050,17 +2050,17 @@ static inline void update_tsk_thread_fla + update_ti_thread_flag(task_thread_info(tsk), flag, value); + } + +-static inline int test_and_set_tsk_thread_flag(struct task_struct *tsk, int flag) ++static inline bool test_and_set_tsk_thread_flag(struct task_struct *tsk, int flag) + { + return test_and_set_ti_thread_flag(task_thread_info(tsk), flag); + } + +-static inline int test_and_clear_tsk_thread_flag(struct task_struct *tsk, int flag) ++static inline bool test_and_clear_tsk_thread_flag(struct task_struct *tsk, int flag) + { + return test_and_clear_ti_thread_flag(task_thread_info(tsk), flag); + } + +-static inline int test_tsk_thread_flag(struct task_struct *tsk, int flag) ++static inline bool test_tsk_thread_flag(struct task_struct *tsk, int flag) + { + return test_ti_thread_flag(task_thread_info(tsk), flag); + } +@@ -2073,9 +2073,11 @@ static inline void set_tsk_need_resched( + static inline void clear_tsk_need_resched(struct task_struct *tsk) + { + clear_tsk_thread_flag(tsk,TIF_NEED_RESCHED); ++ if (IS_ENABLED(CONFIG_PREEMPT_BUILD_AUTO)) ++ clear_tsk_thread_flag(tsk, TIF_NEED_RESCHED_LAZY); + } + +-static inline int test_tsk_need_resched(struct task_struct *tsk) ++static inline bool test_tsk_need_resched(struct task_struct *tsk) + { + return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED)); + } +@@ -2256,7 +2258,7 @@ static inline int rwlock_needbreak(rwloc + + static __always_inline bool need_resched(void) + { +- return unlikely(tif_need_resched()); ++ return unlikely(tif_need_resched_lazy() || tif_need_resched()); + } + + /* +--- a/include/linux/sched/idle.h ++++ b/include/linux/sched/idle.h +@@ -63,7 +63,7 @@ static __always_inline bool __must_check + */ + smp_mb__after_atomic(); + +- return unlikely(tif_need_resched()); ++ return unlikely(need_resched()); + } + + static __always_inline bool __must_check current_clr_polling_and_test(void) +@@ -76,7 +76,7 @@ static __always_inline bool __must_check + */ + smp_mb__after_atomic(); + +- return unlikely(tif_need_resched()); ++ return unlikely(need_resched()); + } + + #else +@@ -85,11 +85,11 @@ static inline void __current_clr_polling + + static inline bool __must_check current_set_polling_and_test(void) + { +- return unlikely(tif_need_resched()); ++ return unlikely(need_resched()); + } + static inline bool __must_check current_clr_polling_and_test(void) + { +- return unlikely(tif_need_resched()); ++ return unlikely(need_resched()); + } + #endif + +--- a/include/linux/thread_info.h ++++ b/include/linux/thread_info.h +@@ -59,6 +59,16 @@ enum syscall_work_bit { + + #include + ++#ifdef CONFIG_PREEMPT_BUILD_AUTO ++# define TIF_NEED_RESCHED_LAZY TIF_ARCH_RESCHED_LAZY ++# define _TIF_NEED_RESCHED_LAZY _TIF_ARCH_RESCHED_LAZY ++# define TIF_NEED_RESCHED_LAZY_OFFSET (TIF_NEED_RESCHED_LAZY - TIF_NEED_RESCHED) ++#else ++# define TIF_NEED_RESCHED_LAZY TIF_NEED_RESCHED ++# define _TIF_NEED_RESCHED_LAZY _TIF_NEED_RESCHED ++# define TIF_NEED_RESCHED_LAZY_OFFSET 0 ++#endif ++ + #ifdef __KERNEL__ + + #ifndef arch_set_restart_data +@@ -185,6 +195,13 @@ static __always_inline bool tif_need_res + (unsigned long *)(¤t_thread_info()->flags)); + } + ++static __always_inline bool tif_need_resched_lazy(void) ++{ ++ return IS_ENABLED(CONFIG_PREEMPT_BUILD_AUTO) && ++ arch_test_bit(TIF_NEED_RESCHED_LAZY, ++ (unsigned long *)(¤t_thread_info()->flags)); ++} ++ + #else + + static __always_inline bool tif_need_resched(void) +@@ -193,6 +210,13 @@ static __always_inline bool tif_need_res + (unsigned long *)(¤t_thread_info()->flags)); + } + ++static __always_inline bool tif_need_resched_lazy(void) ++{ ++ return IS_ENABLED(CONFIG_PREEMPT_BUILD_AUTO) && ++ test_bit(TIF_NEED_RESCHED_LAZY, ++ (unsigned long *)(¤t_thread_info()->flags)); ++} ++ + #endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_NON_ATOMIC_H */ + + #ifndef CONFIG_HAVE_ARCH_WITHIN_STACK_FRAMES +--- a/include/linux/trace_events.h ++++ b/include/linux/trace_events.h +@@ -178,8 +178,8 @@ unsigned int tracing_gen_ctx_irq_test(un + + enum trace_flag_type { + TRACE_FLAG_IRQS_OFF = 0x01, +- TRACE_FLAG_IRQS_NOSUPPORT = 0x02, +- TRACE_FLAG_NEED_RESCHED = 0x04, ++ TRACE_FLAG_NEED_RESCHED = 0x02, ++ TRACE_FLAG_NEED_RESCHED_LAZY = 0x04, + TRACE_FLAG_HARDIRQ = 0x08, + TRACE_FLAG_SOFTIRQ = 0x10, + TRACE_FLAG_PREEMPT_RESCHED = 0x20, +@@ -205,11 +205,11 @@ static inline unsigned int tracing_gen_c + + static inline unsigned int tracing_gen_ctx_flags(unsigned long irqflags) + { +- return tracing_gen_ctx_irq_test(TRACE_FLAG_IRQS_NOSUPPORT); ++ return tracing_gen_ctx_irq_test(0); + } + static inline unsigned int tracing_gen_ctx(void) + { +- return tracing_gen_ctx_irq_test(TRACE_FLAG_IRQS_NOSUPPORT); ++ return tracing_gen_ctx_irq_test(0); + } + #endif + +--- a/kernel/Kconfig.preempt ++++ b/kernel/Kconfig.preempt +@@ -11,6 +11,13 @@ config PREEMPT_BUILD + select PREEMPTION + select UNINLINE_SPIN_UNLOCK if !ARCH_INLINE_SPIN_UNLOCK + ++config PREEMPT_BUILD_AUTO ++ bool ++ select PREEMPT_BUILD ++ ++config HAVE_PREEMPT_AUTO ++ bool ++ + choice + prompt "Preemption Model" + default PREEMPT_NONE +@@ -67,9 +74,17 @@ config PREEMPT + embedded system with latency requirements in the milliseconds + range. + ++config PREEMPT_AUTO ++ bool "Automagic preemption mode with runtime tweaking support" ++ depends on HAVE_PREEMPT_AUTO ++ select PREEMPT_BUILD_AUTO ++ help ++ Add some sensible blurb here ++ + config PREEMPT_RT + bool "Fully Preemptible Kernel (Real-Time)" + depends on EXPERT && ARCH_SUPPORTS_RT ++ select PREEMPT_BUILD_AUTO if HAVE_PREEMPT_AUTO + select PREEMPTION + help + This option turns the kernel into a real-time kernel by replacing +@@ -95,7 +110,7 @@ config PREEMPTION + + config PREEMPT_DYNAMIC + bool "Preemption behaviour defined on boot" +- depends on HAVE_PREEMPT_DYNAMIC && !PREEMPT_RT ++ depends on HAVE_PREEMPT_DYNAMIC && !PREEMPT_RT && !PREEMPT_AUTO + select JUMP_LABEL if HAVE_PREEMPT_DYNAMIC_KEY + select PREEMPT_BUILD + default y if HAVE_PREEMPT_DYNAMIC_CALL +--- a/kernel/entry/common.c ++++ b/kernel/entry/common.c +@@ -155,7 +155,7 @@ static unsigned long exit_to_user_mode_l + + local_irq_enable_exit_to_user(ti_work); + +- if (ti_work & _TIF_NEED_RESCHED) ++ if (ti_work & (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)) + schedule(); + + if (ti_work & _TIF_UPROBE) +@@ -385,7 +385,7 @@ void raw_irqentry_exit_cond_resched(void + rcu_irq_exit_check_preempt(); + if (IS_ENABLED(CONFIG_DEBUG_ENTRY)) + WARN_ON_ONCE(!on_thread_stack()); +- if (need_resched()) ++ if (test_tsk_need_resched(current)) + preempt_schedule_irq(); + } + } +--- a/kernel/entry/kvm.c ++++ b/kernel/entry/kvm.c +@@ -13,7 +13,7 @@ static int xfer_to_guest_mode_work(struc + return -EINTR; + } + +- if (ti_work & _TIF_NEED_RESCHED) ++ if (ti_work & (_TIF_NEED_RESCHED | TIF_NEED_RESCHED_LAZY)) + schedule(); + + if (ti_work & _TIF_NOTIFY_RESUME) +--- a/kernel/sched/core.c ++++ b/kernel/sched/core.c +@@ -898,14 +898,15 @@ static inline void hrtick_rq_init(struct + + #if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG) + /* +- * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG, ++ * Atomically set TIF_NEED_RESCHED[_LAZY] and test for TIF_POLLING_NRFLAG, + * this avoids any races wrt polling state changes and thereby avoids + * spurious IPIs. + */ +-static inline bool set_nr_and_not_polling(struct task_struct *p) ++static inline bool set_nr_and_not_polling(struct task_struct *p, int tif_bit) + { + struct thread_info *ti = task_thread_info(p); +- return !(fetch_or(&ti->flags, _TIF_NEED_RESCHED) & _TIF_POLLING_NRFLAG); ++ ++ return !(fetch_or(&ti->flags, 1 << tif_bit) & _TIF_POLLING_NRFLAG); + } + + /* +@@ -922,7 +923,7 @@ static bool set_nr_if_polling(struct tas + for (;;) { + if (!(val & _TIF_POLLING_NRFLAG)) + return false; +- if (val & _TIF_NEED_RESCHED) ++ if (val & (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)) + return true; + if (try_cmpxchg(&ti->flags, &val, val | _TIF_NEED_RESCHED)) + break; +@@ -931,9 +932,9 @@ static bool set_nr_if_polling(struct tas + } + + #else +-static inline bool set_nr_and_not_polling(struct task_struct *p) ++static inline bool set_nr_and_not_polling(struct task_struct *p, int tif_bit) + { +- set_tsk_need_resched(p); ++ set_tsk_thread_flag(p, tif_bit); + return true; + } + +@@ -1038,28 +1039,47 @@ void wake_up_q(struct wake_q_head *head) + * might also involve a cross-CPU call to trigger the scheduler on + * the target CPU. + */ +-void resched_curr(struct rq *rq) ++static void __resched_curr(struct rq *rq, int lazy) + { ++ int cpu, tif_bit = TIF_NEED_RESCHED + lazy; + struct task_struct *curr = rq->curr; +- int cpu; + + lockdep_assert_rq_held(rq); + +- if (test_tsk_need_resched(curr)) ++ if (unlikely(test_tsk_thread_flag(curr, tif_bit))) + return; + + cpu = cpu_of(rq); + + if (cpu == smp_processor_id()) { +- set_tsk_need_resched(curr); +- set_preempt_need_resched(); ++ set_tsk_thread_flag(curr, tif_bit); ++ if (!lazy) ++ set_preempt_need_resched(); + return; + } + +- if (set_nr_and_not_polling(curr)) +- smp_send_reschedule(cpu); +- else ++ if (set_nr_and_not_polling(curr, tif_bit)) { ++ if (!lazy) ++ smp_send_reschedule(cpu); ++ } else { + trace_sched_wake_idle_without_ipi(cpu); ++ } ++} ++ ++void resched_curr(struct rq *rq) ++{ ++ __resched_curr(rq, 0); ++} ++ ++void resched_curr_lazy(struct rq *rq) ++{ ++ int lazy = IS_ENABLED(CONFIG_PREEMPT_BUILD_AUTO) && !sched_feat(FORCE_NEED_RESCHED) ? ++ TIF_NEED_RESCHED_LAZY_OFFSET : 0; ++ ++ if (lazy && unlikely(test_tsk_thread_flag(rq->curr, TIF_NEED_RESCHED))) ++ return; ++ ++ __resched_curr(rq, lazy); + } + + void resched_cpu(int cpu) +@@ -1132,7 +1152,7 @@ static void wake_up_idle_cpu(int cpu) + if (cpu == smp_processor_id()) + return; + +- if (set_nr_and_not_polling(rq->idle)) ++ if (set_nr_and_not_polling(rq->idle, TIF_NEED_RESCHED)) + smp_send_reschedule(cpu); + else + trace_sched_wake_idle_without_ipi(cpu); +--- a/kernel/sched/debug.c ++++ b/kernel/sched/debug.c +@@ -333,6 +333,23 @@ static const struct file_operations sche + .release = seq_release, + }; + ++static ssize_t sched_hog_write(struct file *filp, const char __user *ubuf, ++ size_t cnt, loff_t *ppos) ++{ ++ unsigned long end = jiffies + 60 * HZ; ++ ++ for (; time_before(jiffies, end) && !signal_pending(current);) ++ cpu_relax(); ++ ++ return cnt; ++} ++ ++static const struct file_operations sched_hog_fops = { ++ .write = sched_hog_write, ++ .open = simple_open, ++ .llseek = default_llseek, ++}; ++ + static struct dentry *debugfs_sched; + + static __init int sched_init_debug(void) +@@ -374,6 +391,8 @@ static __init int sched_init_debug(void) + + debugfs_create_file("debug", 0444, debugfs_sched, NULL, &sched_debug_fops); + ++ debugfs_create_file("hog", 0200, debugfs_sched, NULL, &sched_hog_fops); ++ + return 0; + } + late_initcall(sched_init_debug); +--- a/kernel/sched/fair.c ++++ b/kernel/sched/fair.c +@@ -1016,8 +1016,10 @@ static void clear_buddies(struct cfs_rq + * XXX: strictly: vd_i += N*r_i/w_i such that: vd_i > ve_i + * this is probably good enough. + */ +-static void update_deadline(struct cfs_rq *cfs_rq, struct sched_entity *se) ++static void update_deadline(struct cfs_rq *cfs_rq, struct sched_entity *se, bool tick) + { ++ struct rq *rq = rq_of(cfs_rq); ++ + if ((s64)(se->vruntime - se->deadline) < 0) + return; + +@@ -1036,10 +1038,19 @@ static void update_deadline(struct cfs_r + /* + * The task has consumed its request, reschedule. + */ +- if (cfs_rq->nr_running > 1) { +- resched_curr(rq_of(cfs_rq)); +- clear_buddies(cfs_rq, se); ++ if (cfs_rq->nr_running < 2) ++ return; ++ ++ if (!IS_ENABLED(CONFIG_PREEMPT_BUILD_AUTO) || sched_feat(FORCE_NEED_RESCHED)) { ++ resched_curr(rq); ++ } else { ++ /* Did the task ignore the lazy reschedule request? */ ++ if (tick && test_tsk_thread_flag(rq->curr, TIF_NEED_RESCHED_LAZY)) ++ resched_curr(rq); ++ else ++ resched_curr_lazy(rq); + } ++ clear_buddies(cfs_rq, se); + } + + #include "pelt.h" +@@ -1147,7 +1158,7 @@ static void update_tg_load_avg(struct cf + /* + * Update the current task's runtime statistics. + */ +-static void update_curr(struct cfs_rq *cfs_rq) ++static void __update_curr(struct cfs_rq *cfs_rq, bool tick) + { + struct sched_entity *curr = cfs_rq->curr; + u64 now = rq_clock_task(rq_of(cfs_rq)); +@@ -1174,7 +1185,7 @@ static void update_curr(struct cfs_rq *c + schedstat_add(cfs_rq->exec_clock, delta_exec); + + curr->vruntime += calc_delta_fair(delta_exec, curr); +- update_deadline(cfs_rq, curr); ++ update_deadline(cfs_rq, curr, tick); + update_min_vruntime(cfs_rq); + + if (entity_is_task(curr)) { +@@ -1188,6 +1199,11 @@ static void update_curr(struct cfs_rq *c + account_cfs_rq_runtime(cfs_rq, delta_exec); + } + ++static inline void update_curr(struct cfs_rq *cfs_rq) ++{ ++ __update_curr(cfs_rq, false); ++} ++ + static void update_curr_fair(struct rq *rq) + { + update_curr(cfs_rq_of(&rq->curr->se)); +@@ -5398,7 +5414,7 @@ entity_tick(struct cfs_rq *cfs_rq, struc + /* + * Update run-time statistics of the 'current'. + */ +- update_curr(cfs_rq); ++ __update_curr(cfs_rq, true); + + /* + * Ensure that runnable average is periodically updated. +@@ -5412,7 +5428,7 @@ entity_tick(struct cfs_rq *cfs_rq, struc + * validating it and just reschedule. + */ + if (queued) { +- resched_curr(rq_of(cfs_rq)); ++ resched_curr_lazy(rq_of(cfs_rq)); + return; + } + /* +@@ -5558,7 +5574,7 @@ static void __account_cfs_rq_runtime(str + * hierarchy can be throttled + */ + if (!assign_cfs_rq_runtime(cfs_rq) && likely(cfs_rq->curr)) +- resched_curr(rq_of(cfs_rq)); ++ resched_curr_lazy(rq_of(cfs_rq)); + } + + static __always_inline +@@ -5818,7 +5834,7 @@ void unthrottle_cfs_rq(struct cfs_rq *cf + + /* Determine whether we need to wake up potentially idle CPU: */ + if (rq->curr == rq->idle && rq->cfs.nr_running) +- resched_curr(rq); ++ resched_curr_lazy(rq); + } + + #ifdef CONFIG_SMP +@@ -6523,7 +6539,7 @@ static void hrtick_start_fair(struct rq + + if (delta < 0) { + if (task_current(rq, p)) +- resched_curr(rq); ++ resched_curr_lazy(rq); + return; + } + hrtick_start(rq, delta); +@@ -8175,7 +8191,7 @@ static void check_preempt_wakeup(struct + * prevents us from potentially nominating it as a false LAST_BUDDY + * below. + */ +- if (test_tsk_need_resched(curr)) ++ if (need_resched()) + return; + + /* Idle tasks are by definition preempted by non-idle tasks. */ +@@ -8217,7 +8233,7 @@ static void check_preempt_wakeup(struct + return; + + preempt: +- resched_curr(rq); ++ resched_curr_lazy(rq); + } + + #ifdef CONFIG_SMP +@@ -12374,7 +12390,7 @@ static inline void task_tick_core(struct + */ + if (rq->core->core_forceidle_count && rq->cfs.nr_running == 1 && + __entity_slice_used(&curr->se, MIN_NR_TASKS_DURING_FORCEIDLE)) +- resched_curr(rq); ++ resched_curr_lazy(rq); + } + + /* +@@ -12539,7 +12555,7 @@ prio_changed_fair(struct rq *rq, struct + */ + if (task_current(rq, p)) { + if (p->prio > oldprio) +- resched_curr(rq); ++ resched_curr_lazy(rq); + } else + check_preempt_curr(rq, p, 0); + } +--- a/kernel/sched/features.h ++++ b/kernel/sched/features.h +@@ -89,3 +89,5 @@ SCHED_FEAT(UTIL_EST_FASTUP, true) + SCHED_FEAT(LATENCY_WARN, false) + + SCHED_FEAT(HZ_BW, true) ++ ++SCHED_FEAT(FORCE_NEED_RESCHED, false) +--- a/kernel/sched/idle.c ++++ b/kernel/sched/idle.c +@@ -57,8 +57,7 @@ static noinline int __cpuidle cpu_idle_p + ct_cpuidle_enter(); + + raw_local_irq_enable(); +- while (!tif_need_resched() && +- (cpu_idle_force_poll || tick_check_broadcast_expired())) ++ while (!need_resched() && (cpu_idle_force_poll || tick_check_broadcast_expired())) + cpu_relax(); + raw_local_irq_disable(); + +--- a/kernel/sched/sched.h ++++ b/kernel/sched/sched.h +@@ -2435,6 +2435,7 @@ extern void init_sched_fair_class(void); + extern void reweight_task(struct task_struct *p, int prio); + + extern void resched_curr(struct rq *rq); ++extern void resched_curr_lazy(struct rq *rq); + extern void resched_cpu(int cpu); + + extern struct rt_bandwidth def_rt_bandwidth; +--- a/kernel/trace/trace.c ++++ b/kernel/trace/trace.c +@@ -2722,6 +2722,8 @@ unsigned int tracing_gen_ctx_irq_test(un + + if (tif_need_resched()) + trace_flags |= TRACE_FLAG_NEED_RESCHED; ++ if (tif_need_resched_lazy()) ++ trace_flags |= TRACE_FLAG_NEED_RESCHED_LAZY; + if (test_preempt_need_resched()) + trace_flags |= TRACE_FLAG_PREEMPT_RESCHED; + return (trace_flags << 16) | (min_t(unsigned int, pc & 0xff, 0xf)) | +--- a/kernel/trace/trace_output.c ++++ b/kernel/trace/trace_output.c +@@ -460,17 +460,29 @@ int trace_print_lat_fmt(struct trace_seq + (entry->flags & TRACE_FLAG_IRQS_OFF && bh_off) ? 'D' : + (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' : + bh_off ? 'b' : +- (entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' : ++ !IS_ENABLED(CONFIG_TRACE_IRQFLAGS_SUPPORT) ? 'X' : + '.'; + +- switch (entry->flags & (TRACE_FLAG_NEED_RESCHED | ++ switch (entry->flags & (TRACE_FLAG_NEED_RESCHED | TRACE_FLAG_NEED_RESCHED_LAZY | + TRACE_FLAG_PREEMPT_RESCHED)) { ++ case TRACE_FLAG_NEED_RESCHED | TRACE_FLAG_NEED_RESCHED_LAZY | TRACE_FLAG_PREEMPT_RESCHED: ++ need_resched = 'B'; ++ break; + case TRACE_FLAG_NEED_RESCHED | TRACE_FLAG_PREEMPT_RESCHED: + need_resched = 'N'; + break; ++ case TRACE_FLAG_NEED_RESCHED_LAZY | TRACE_FLAG_PREEMPT_RESCHED: ++ need_resched = 'L'; ++ break; ++ case TRACE_FLAG_NEED_RESCHED | TRACE_FLAG_NEED_RESCHED_LAZY: ++ need_resched = 'b'; ++ break; + case TRACE_FLAG_NEED_RESCHED: + need_resched = 'n'; + break; ++ case TRACE_FLAG_NEED_RESCHED_LAZY: ++ need_resched = 'l'; ++ break; + case TRACE_FLAG_PREEMPT_RESCHED: + need_resched = 'p'; + break; diff --git a/debian/patches-rt/RISC-V-Probe-misaligned-access-speed-in-parallel.patch b/debian/patches-rt/RISC-V-Probe-misaligned-access-speed-in-parallel.patch new file mode 100644 index 000000000..78e57b07a --- /dev/null +++ b/debian/patches-rt/RISC-V-Probe-misaligned-access-speed-in-parallel.patch @@ -0,0 +1,197 @@ +From: Evan Green +Date: Mon, 6 Nov 2023 14:58:55 -0800 +Subject: [PATCH] RISC-V: Probe misaligned access speed in parallel +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Probing for misaligned access speed takes about 0.06 seconds. On a +system with 64 cores, doing this in smp_callin() means it's done +serially, extending boot time by 3.8 seconds. That's a lot of boot time. + +Instead of measuring each CPU serially, let's do the measurements on +all CPUs in parallel. If we disable preemption on all CPUs, the +jiffies stop ticking, so we can do this in stages of 1) everybody +except core 0, then 2) core 0. The allocations are all done outside of +on_each_cpu() to avoid calling alloc_pages() with interrupts disabled. + +For hotplugged CPUs that come in after the boot time measurement, +register CPU hotplug callbacks, and do the measurement there. Interrupts +are enabled in those callbacks, so they're fine to do alloc_pages() in. + +[bigeasy: merge the individual patches into the final step.] + +Reported-by: Jisheng Zhang +Closes: https://lore.kernel.org/all/mhng-9359993d-6872-4134-83ce-c97debe1cf9a@palmer-ri-x1c9/T/#mae9b8f40016f9df428829d33360144dc5026bcbf +Fixes: 584ea6564bca ("RISC-V: Probe for unaligned access speed") +Signed-off-by: Evan Green +Link: https://lore.kernel.org/r/20231106225855.3121724-1-evan@rivosinc.com +Signed-off-by: Palmer Dabbelt +Signed-off-by: Sebastian Andrzej Siewior +--- + arch/riscv/include/asm/cpufeature.h | 2 + arch/riscv/kernel/cpufeature.c | 90 ++++++++++++++++++++++++++++++------ + arch/riscv/kernel/smpboot.c | 1 + 3 files changed, 76 insertions(+), 17 deletions(-) + +--- a/arch/riscv/include/asm/cpufeature.h ++++ b/arch/riscv/include/asm/cpufeature.h +@@ -30,6 +30,4 @@ DECLARE_PER_CPU(long, misaligned_access_ + /* Per-cpu ISA extensions. */ + extern struct riscv_isainfo hart_isa[NR_CPUS]; + +-void check_unaligned_access(int cpu); +- + #endif +--- a/arch/riscv/kernel/cpufeature.c ++++ b/arch/riscv/kernel/cpufeature.c +@@ -8,6 +8,7 @@ + + #include + #include ++#include + #include + #include + #include +@@ -29,6 +30,7 @@ + + #define MISALIGNED_ACCESS_JIFFIES_LG2 1 + #define MISALIGNED_BUFFER_SIZE 0x4000 ++#define MISALIGNED_BUFFER_ORDER get_order(MISALIGNED_BUFFER_SIZE) + #define MISALIGNED_COPY_SIZE ((MISALIGNED_BUFFER_SIZE / 2) - 0x80) + + unsigned long elf_hwcap __read_mostly; +@@ -556,24 +558,19 @@ unsigned long riscv_get_elf_hwcap(void) + return hwcap; + } + +-void check_unaligned_access(int cpu) ++static int check_unaligned_access(void *param) + { ++ int cpu = smp_processor_id(); + u64 start_cycles, end_cycles; + u64 word_cycles; + u64 byte_cycles; + int ratio; + unsigned long start_jiffies, now; +- struct page *page; ++ struct page *page = param; + void *dst; + void *src; + long speed = RISCV_HWPROBE_MISALIGNED_SLOW; + +- page = alloc_pages(GFP_NOWAIT, get_order(MISALIGNED_BUFFER_SIZE)); +- if (!page) { +- pr_warn("Can't alloc pages to measure memcpy performance"); +- return; +- } +- + /* Make an unaligned destination buffer. */ + dst = (void *)((unsigned long)page_address(page) | 0x1); + /* Unalign src as well, but differently (off by 1 + 2 = 3). */ +@@ -626,7 +623,7 @@ void check_unaligned_access(int cpu) + pr_warn("cpu%d: rdtime lacks granularity needed to measure unaligned access speed\n", + cpu); + +- goto out; ++ return 0; + } + + if (word_cycles < byte_cycles) +@@ -640,18 +637,83 @@ void check_unaligned_access(int cpu) + (speed == RISCV_HWPROBE_MISALIGNED_FAST) ? "fast" : "slow"); + + per_cpu(misaligned_access_speed, cpu) = speed; ++ return 0; ++} + +-out: +- __free_pages(page, get_order(MISALIGNED_BUFFER_SIZE)); ++static void check_unaligned_access_nonboot_cpu(void *param) ++{ ++ unsigned int cpu = smp_processor_id(); ++ struct page **pages = param; ++ ++ if (smp_processor_id() != 0) ++ check_unaligned_access(pages[cpu]); ++} ++ ++static int riscv_online_cpu(unsigned int cpu) ++{ ++ static struct page *buf; ++ ++ /* We are already set since the last check */ ++ if (per_cpu(misaligned_access_speed, cpu) != RISCV_HWPROBE_MISALIGNED_UNKNOWN) ++ return 0; ++ ++ buf = alloc_pages(GFP_KERNEL, MISALIGNED_BUFFER_ORDER); ++ if (!buf) { ++ pr_warn("Allocation failure, not measuring misaligned performance\n"); ++ return -ENOMEM; ++ } ++ ++ check_unaligned_access(buf); ++ __free_pages(buf, MISALIGNED_BUFFER_ORDER); ++ return 0; + } + +-static int check_unaligned_access_boot_cpu(void) ++/* Measure unaligned access on all CPUs present at boot in parallel. */ ++static int check_unaligned_access_all_cpus(void) + { +- check_unaligned_access(0); ++ unsigned int cpu; ++ unsigned int cpu_count = num_possible_cpus(); ++ struct page **bufs = kzalloc(cpu_count * sizeof(struct page *), ++ GFP_KERNEL); ++ ++ if (!bufs) { ++ pr_warn("Allocation failure, not measuring misaligned performance\n"); ++ return 0; ++ } ++ ++ /* ++ * Allocate separate buffers for each CPU so there's no fighting over ++ * cache lines. ++ */ ++ for_each_cpu(cpu, cpu_online_mask) { ++ bufs[cpu] = alloc_pages(GFP_KERNEL, MISALIGNED_BUFFER_ORDER); ++ if (!bufs[cpu]) { ++ pr_warn("Allocation failure, not measuring misaligned performance\n"); ++ goto out; ++ } ++ } ++ ++ /* Check everybody except 0, who stays behind to tend jiffies. */ ++ on_each_cpu(check_unaligned_access_nonboot_cpu, bufs, 1); ++ ++ /* Check core 0. */ ++ smp_call_on_cpu(0, check_unaligned_access, bufs[0], true); ++ ++ /* Setup hotplug callback for any new CPUs that come online. */ ++ cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "riscv:online", ++ riscv_online_cpu, NULL); ++ ++out: ++ for_each_cpu(cpu, cpu_online_mask) { ++ if (bufs[cpu]) ++ __free_pages(bufs[cpu], MISALIGNED_BUFFER_ORDER); ++ } ++ ++ kfree(bufs); + return 0; + } + +-arch_initcall(check_unaligned_access_boot_cpu); ++arch_initcall(check_unaligned_access_all_cpus); + + #ifdef CONFIG_RISCV_ALTERNATIVE + /* +--- a/arch/riscv/kernel/smpboot.c ++++ b/arch/riscv/kernel/smpboot.c +@@ -246,7 +246,6 @@ asmlinkage __visible void smp_callin(voi + + numa_add_cpu(curr_cpuid); + set_cpu_online(curr_cpuid, 1); +- check_unaligned_access(curr_cpuid); + + if (has_vector()) { + if (riscv_v_setup_vsize()) diff --git a/debian/patches-rt/Revert-drm-i915-Depend-on-PREEMPT_RT.patch b/debian/patches-rt/Revert-drm-i915-Depend-on-PREEMPT_RT.patch new file mode 100644 index 000000000..dc62e007e --- /dev/null +++ b/debian/patches-rt/Revert-drm-i915-Depend-on-PREEMPT_RT.patch @@ -0,0 +1,23 @@ +From: Sebastian Andrzej Siewior +Date: Mon, 21 Feb 2022 17:59:14 +0100 +Subject: [PATCH] Revert "drm/i915: Depend on !PREEMPT_RT." +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Once the known issues are addressed, it should be safe to enable the +driver. + +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/gpu/drm/i915/Kconfig | 1 - + 1 file changed, 1 deletion(-) + +--- a/drivers/gpu/drm/i915/Kconfig ++++ b/drivers/gpu/drm/i915/Kconfig +@@ -3,7 +3,6 @@ config DRM_I915 + tristate "Intel 8xx/9xx/G3x/G4x/HD Graphics" + depends on DRM + depends on X86 && PCI +- depends on !PREEMPT_RT + select INTEL_GTT if X86 + select INTERVAL_TREE + # we need shmfs for the swappable backing store, and in particular diff --git a/debian/patches-rt/drm-i915-Do-not-disable-preemption-for-resets.patch b/debian/patches-rt/drm-i915-Do-not-disable-preemption-for-resets.patch new file mode 100644 index 000000000..586966703 --- /dev/null +++ b/debian/patches-rt/drm-i915-Do-not-disable-preemption-for-resets.patch @@ -0,0 +1,99 @@ +From: Tvrtko Ursulin +Date: Wed, 5 Jul 2023 10:30:25 +0100 +Subject: [PATCH] drm/i915: Do not disable preemption for resets +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Commit ade8a0f59844 ("drm/i915: Make all GPU resets atomic") added a +preempt disable section over the hardware reset callback to prepare the +driver for being able to reset from atomic contexts. + +In retrospect I can see that the work item at a time was about removing +the struct mutex from the reset path. Code base also briefly entertained +the idea of doing the reset under stop_machine in order to serialize +userspace mmap and temporary glitch in the fence registers (see +eb8d0f5af4ec ("drm/i915: Remove GPU reset dependence on struct_mutex"), +but that never materialized and was soon removed in 2caffbf11762 +("drm/i915: Revoke mmaps and prevent access to fence registers across +reset") and replaced with a SRCU based solution. + +As such, as far as I can see, today we still have a requirement that +resets must not sleep (invoked from submission tasklets), but no need to +support invoking them from a truly atomic context. + +Given that the preemption section is problematic on RT kernels, since the +uncore lock becomes a sleeping lock and so is invalid in such section, +lets try and remove it. Potential downside is that our short waits on GPU +to complete the reset may get extended if CPU scheduling interferes, but +in practice that probably isn't a deal breaker. + +In terms of mechanics, since the preemption disabled block is being +removed we just need to replace a few of the wait_for_atomic macros into +busy looping versions which will work (and not complain) when called from +non-atomic sections. + +Signed-off-by: Tvrtko Ursulin +Cc: Chris Wilson +Cc: Paul Gortmaker +Cc: Sebastian Andrzej Siewior +Acked-by: Sebastian Andrzej Siewior +Link: https://lore.kernel.org/r/20230705093025.3689748-1-tvrtko.ursulin@linux.intel.com +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/gpu/drm/i915/gt/intel_reset.c | 12 +++++------- + 1 file changed, 5 insertions(+), 7 deletions(-) + +--- a/drivers/gpu/drm/i915/gt/intel_reset.c ++++ b/drivers/gpu/drm/i915/gt/intel_reset.c +@@ -164,13 +164,13 @@ static int i915_do_reset(struct intel_gt + /* Assert reset for at least 20 usec, and wait for acknowledgement. */ + pci_write_config_byte(pdev, I915_GDRST, GRDOM_RESET_ENABLE); + udelay(50); +- err = wait_for_atomic(i915_in_reset(pdev), 50); ++ err = _wait_for_atomic(i915_in_reset(pdev), 50, 0); + + /* Clear the reset request. */ + pci_write_config_byte(pdev, I915_GDRST, 0); + udelay(50); + if (!err) +- err = wait_for_atomic(!i915_in_reset(pdev), 50); ++ err = _wait_for_atomic(!i915_in_reset(pdev), 50, 0); + + return err; + } +@@ -190,7 +190,7 @@ static int g33_do_reset(struct intel_gt + struct pci_dev *pdev = to_pci_dev(gt->i915->drm.dev); + + pci_write_config_byte(pdev, I915_GDRST, GRDOM_RESET_ENABLE); +- return wait_for_atomic(g4x_reset_complete(pdev), 50); ++ return _wait_for_atomic(g4x_reset_complete(pdev), 50, 0); + } + + static int g4x_do_reset(struct intel_gt *gt, +@@ -207,7 +207,7 @@ static int g4x_do_reset(struct intel_gt + + pci_write_config_byte(pdev, I915_GDRST, + GRDOM_MEDIA | GRDOM_RESET_ENABLE); +- ret = wait_for_atomic(g4x_reset_complete(pdev), 50); ++ ret = _wait_for_atomic(g4x_reset_complete(pdev), 50, 0); + if (ret) { + GT_TRACE(gt, "Wait for media reset failed\n"); + goto out; +@@ -215,7 +215,7 @@ static int g4x_do_reset(struct intel_gt + + pci_write_config_byte(pdev, I915_GDRST, + GRDOM_RENDER | GRDOM_RESET_ENABLE); +- ret = wait_for_atomic(g4x_reset_complete(pdev), 50); ++ ret = _wait_for_atomic(g4x_reset_complete(pdev), 50, 0); + if (ret) { + GT_TRACE(gt, "Wait for render reset failed\n"); + goto out; +@@ -785,9 +785,7 @@ int __intel_gt_reset(struct intel_gt *gt + reset_mask = wa_14015076503_start(gt, engine_mask, !retry); + + GT_TRACE(gt, "engine_mask=%x\n", reset_mask); +- preempt_disable(); + ret = reset(gt, reset_mask, retry); +- preempt_enable(); + + wa_14015076503_end(gt, reset_mask); + } diff --git a/debian/patches-rt/drm-i915-guc-Consider-also-RCU-depth-in-busy-loop.patch b/debian/patches-rt/drm-i915-guc-Consider-also-RCU-depth-in-busy-loop.patch new file mode 100644 index 000000000..0f030b42f --- /dev/null +++ b/debian/patches-rt/drm-i915-guc-Consider-also-RCU-depth-in-busy-loop.patch @@ -0,0 +1,29 @@ +From: Sebastian Andrzej Siewior +Date: Tue, 3 Oct 2023 21:37:21 +0200 +Subject: [PATCH] drm/i915/guc: Consider also RCU depth in busy loop. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +intel_guc_send_busy_loop() looks at in_atomic() and irqs_disabled() to +decide if it should busy-spin while waiting or if it may sleep. +Both checks will report false on PREEMPT_RT if sleeping spinlocks are +acquired leading to RCU splats while the function sleeps. + +Check also if RCU has been disabled. + +Reported-by: "John B. Wyatt IV" +Signed-off-by: Sebastian Andrzej Siewior +--- + drivers/gpu/drm/i915/gt/uc/intel_guc.h | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +--- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h ++++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h +@@ -317,7 +317,7 @@ static inline int intel_guc_send_busy_lo + { + int err; + unsigned int sleep_period_ms = 1; +- bool not_atomic = !in_atomic() && !irqs_disabled(); ++ bool not_atomic = !in_atomic() && !irqs_disabled() && !rcu_preempt_depth(); + + /* + * FIXME: Have caller pass in if we are in an atomic context to avoid diff --git a/debian/patches-rt/net-Avoid-the-IPI-to-free-the.patch b/debian/patches-rt/net-Avoid-the-IPI-to-free-the.patch new file mode 100644 index 000000000..6005e7a2e --- /dev/null +++ b/debian/patches-rt/net-Avoid-the-IPI-to-free-the.patch @@ -0,0 +1,119 @@ +From: Sebastian Andrzej Siewior +Date: Mon, 15 Aug 2022 17:29:50 +0200 +Subject: [PATCH] net: Avoid the IPI to free the +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +skb_attempt_defer_free() collects a skbs, which was allocated on a +remote CPU, on a per-CPU list. These skbs are either freed on that +remote CPU once the CPU enters NET_RX or an remote IPI function is +invoked in to raise the NET_RX softirq if a threshold of pending skb has +been exceeded. +This remote IPI can cause the wakeup of ksoftirqd on PREEMPT_RT if the +remote CPU idle was idle. This is undesired because once the ksoftirqd +is running it will acquire all pending softirqs and they will not be +executed as part of the threaded interrupt until ksoftird goes idle +again. + +To void all this, schedule the deferred clean up from a worker. + +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/netdevice.h | 4 ++++ + net/core/dev.c | 39 ++++++++++++++++++++++++++++++--------- + net/core/skbuff.c | 7 ++++++- + 3 files changed, 40 insertions(+), 10 deletions(-) + +--- a/include/linux/netdevice.h ++++ b/include/linux/netdevice.h +@@ -3258,7 +3258,11 @@ struct softnet_data { + int defer_count; + int defer_ipi_scheduled; + struct sk_buff *defer_list; ++#ifndef CONFIG_PREEMPT_RT + call_single_data_t defer_csd; ++#else ++ struct work_struct defer_work; ++#endif + }; + + static inline void input_queue_head_incr(struct softnet_data *sd) +--- a/net/core/dev.c ++++ b/net/core/dev.c +@@ -4702,15 +4702,6 @@ static void rps_trigger_softirq(void *da + + #endif /* CONFIG_RPS */ + +-/* Called from hardirq (IPI) context */ +-static void trigger_rx_softirq(void *data) +-{ +- struct softnet_data *sd = data; +- +- __raise_softirq_irqoff(NET_RX_SOFTIRQ); +- smp_store_release(&sd->defer_ipi_scheduled, 0); +-} +- + /* + * After we queued a packet into sd->input_pkt_queue, + * we need to make sure this queue is serviced soon. +@@ -6679,6 +6670,32 @@ static void skb_defer_free_flush(struct + } + } + ++#ifndef CONFIG_PREEMPT_RT ++ ++/* Called from hardirq (IPI) context */ ++static void trigger_rx_softirq(void *data) ++{ ++ struct softnet_data *sd = data; ++ ++ __raise_softirq_irqoff(NET_RX_SOFTIRQ); ++ smp_store_release(&sd->defer_ipi_scheduled, 0); ++} ++ ++#else ++ ++static void trigger_rx_softirq(struct work_struct *defer_work) ++{ ++ struct softnet_data *sd; ++ ++ sd = container_of(defer_work, struct softnet_data, defer_work); ++ smp_store_release(&sd->defer_ipi_scheduled, 0); ++ local_bh_disable(); ++ skb_defer_free_flush(sd); ++ local_bh_enable(); ++} ++ ++#endif ++ + static int napi_threaded_poll(void *data) + { + struct napi_struct *napi = data; +@@ -11603,7 +11620,11 @@ static int __init net_dev_init(void) + INIT_CSD(&sd->csd, rps_trigger_softirq, sd); + sd->cpu = i; + #endif ++#ifndef CONFIG_PREEMPT_RT + INIT_CSD(&sd->defer_csd, trigger_rx_softirq, sd); ++#else ++ INIT_WORK(&sd->defer_work, trigger_rx_softirq); ++#endif + spin_lock_init(&sd->defer_lock); + + init_gro_hash(&sd->backlog); +--- a/net/core/skbuff.c ++++ b/net/core/skbuff.c +@@ -6841,8 +6841,13 @@ nodefer: __kfree_skb(skb); + /* Make sure to trigger NET_RX_SOFTIRQ on the remote CPU + * if we are unlucky enough (this seems very unlikely). + */ +- if (unlikely(kick) && !cmpxchg(&sd->defer_ipi_scheduled, 0, 1)) ++ if (unlikely(kick) && !cmpxchg(&sd->defer_ipi_scheduled, 0, 1)) { ++#ifndef CONFIG_PREEMPT_RT + smp_call_function_single_async(cpu, &sd->defer_csd); ++#else ++ schedule_work_on(cpu, &sd->defer_work); ++#endif ++ } + } + + static void skb_splice_csum_page(struct sk_buff *skb, struct page *page, diff --git a/debian/patches-rt/powerpc-pseries-Select-the-generic-memory-allocator.patch b/debian/patches-rt/powerpc-pseries-Select-the-generic-memory-allocator.patch new file mode 100644 index 000000000..6eb1f4c87 --- /dev/null +++ b/debian/patches-rt/powerpc-pseries-Select-the-generic-memory-allocator.patch @@ -0,0 +1,27 @@ +From: Sebastian Andrzej Siewior +Date: Thu, 9 Mar 2023 09:13:52 +0100 +Subject: [PATCH] powerpc/pseries: Select the generic memory allocator. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +The RTAS work area allocator is using the generic memory allocator and +as such it must select it. + +Select the generic memory allocator on pseries. + +Fixes: 43033bc62d349 ("powerpc/pseries: add RTAS work area allocator") +Signed-off-by: Sebastian Andrzej Siewior +Link: https://lore.kernel.org/20230309135110.uAxhqRFk@linutronix.de +--- + arch/powerpc/platforms/pseries/Kconfig | 1 + + 1 file changed, 1 insertion(+) + +--- a/arch/powerpc/platforms/pseries/Kconfig ++++ b/arch/powerpc/platforms/pseries/Kconfig +@@ -2,6 +2,7 @@ + config PPC_PSERIES + depends on PPC64 && PPC_BOOK3S + bool "IBM pSeries & new (POWER5-based) iSeries" ++ select GENERIC_ALLOCATOR + select HAVE_PCSPKR_PLATFORM + select MPIC + select OF_DYNAMIC diff --git a/debian/patches-rt/powerpc__traps__Use_PREEMPT_RT.patch b/debian/patches-rt/powerpc__traps__Use_PREEMPT_RT.patch new file mode 100644 index 000000000..de8c14fd7 --- /dev/null +++ b/debian/patches-rt/powerpc__traps__Use_PREEMPT_RT.patch @@ -0,0 +1,38 @@ +Subject: powerpc: traps: Use PREEMPT_RT +From: Sebastian Andrzej Siewior +Date: Fri Jul 26 11:30:49 2019 +0200 +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +From: Sebastian Andrzej Siewior + +Add PREEMPT_RT to the backtrace if enabled. + +Signed-off-by: Sebastian Andrzej Siewior +Signed-off-by: Thomas Gleixner + + +--- + arch/powerpc/kernel/traps.c | 7 ++++++- + 1 file changed, 6 insertions(+), 1 deletion(-) +--- +--- a/arch/powerpc/kernel/traps.c ++++ b/arch/powerpc/kernel/traps.c +@@ -261,12 +261,17 @@ static char *get_mmu_str(void) + + static int __die(const char *str, struct pt_regs *regs, long err) + { ++ const char *pr = ""; ++ + printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter); + ++ if (IS_ENABLED(CONFIG_PREEMPTION)) ++ pr = IS_ENABLED(CONFIG_PREEMPT_RT) ? " PREEMPT_RT" : " PREEMPT"; ++ + printk("%s PAGE_SIZE=%luK%s%s%s%s%s%s %s\n", + IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN) ? "LE" : "BE", + PAGE_SIZE / 1024, get_mmu_str(), +- IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT" : "", ++ pr, + IS_ENABLED(CONFIG_SMP) ? " SMP" : "", + IS_ENABLED(CONFIG_SMP) ? (" NR_CPUS=" __stringify(NR_CPUS)) : "", + debug_pagealloc_enabled() ? " DEBUG_PAGEALLOC" : "", diff --git a/debian/patches-rt/powerpc_kvm__Disable_in-kernel_MPIC_emulation_for_PREEMPT_RT.patch b/debian/patches-rt/powerpc_kvm__Disable_in-kernel_MPIC_emulation_for_PREEMPT_RT.patch new file mode 100644 index 000000000..f53f527b3 --- /dev/null +++ b/debian/patches-rt/powerpc_kvm__Disable_in-kernel_MPIC_emulation_for_PREEMPT_RT.patch @@ -0,0 +1,43 @@ +Subject: powerpc/kvm: Disable in-kernel MPIC emulation for PREEMPT_RT +From: Bogdan Purcareata +Date: Fri Apr 24 15:53:13 2015 +0000 +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +From: Bogdan Purcareata + +While converting the openpic emulation code to use a raw_spinlock_t enables +guests to run on RT, there's still a performance issue. For interrupts sent in +directed delivery mode with a multiple CPU mask, the emulated openpic will loop +through all of the VCPUs, and for each VCPUs, it call IRQ_check, which will loop +through all the pending interrupts for that VCPU. This is done while holding the +raw_lock, meaning that in all this time the interrupts and preemption are +disabled on the host Linux. A malicious user app can max both these number and +cause a DoS. + +This temporary fix is sent for two reasons. First is so that users who want to +use the in-kernel MPIC emulation are aware of the potential latencies, thus +making sure that the hardware MPIC and their usage scenario does not involve +interrupts sent in directed delivery mode, and the number of possible pending +interrupts is kept small. Secondly, this should incentivize the development of a +proper openpic emulation that would be better suited for RT. + +Acked-by: Scott Wood +Signed-off-by: Bogdan Purcareata +Signed-off-by: Sebastian Andrzej Siewior +Signed-off-by: Thomas Gleixner + + +--- + arch/powerpc/kvm/Kconfig | 1 + + 1 file changed, 1 insertion(+) +--- +--- a/arch/powerpc/kvm/Kconfig ++++ b/arch/powerpc/kvm/Kconfig +@@ -224,6 +224,7 @@ config KVM_E500MC + config KVM_MPIC + bool "KVM in-kernel MPIC emulation" + depends on KVM && PPC_E500 ++ depends on !PREEMPT_RT + select HAVE_KVM_IRQCHIP + select HAVE_KVM_IRQFD + select HAVE_KVM_IRQ_ROUTING diff --git a/debian/patches-rt/powerpc_pseries_iommu__Use_a_locallock_instead_local_irq_save.patch b/debian/patches-rt/powerpc_pseries_iommu__Use_a_locallock_instead_local_irq_save.patch new file mode 100644 index 000000000..f20adf29e --- /dev/null +++ b/debian/patches-rt/powerpc_pseries_iommu__Use_a_locallock_instead_local_irq_save.patch @@ -0,0 +1,115 @@ +Subject: powerpc/pseries/iommu: Use a locallock instead local_irq_save() +From: Sebastian Andrzej Siewior +Date: Tue Mar 26 18:31:54 2019 +0100 +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +From: Sebastian Andrzej Siewior + +The locallock protects the per-CPU variable tce_page. The function +attempts to allocate memory while tce_page is protected (by disabling +interrupts). + +Use local_irq_save() instead of local_irq_disable(). + +Cc: stable-rt@vger.kernel.org +Signed-off-by: Sebastian Andrzej Siewior +Signed-off-by: Thomas Gleixner + + +--- + arch/powerpc/platforms/pseries/iommu.c | 31 ++++++++++++++++++++----------- + 1 file changed, 20 insertions(+), 11 deletions(-) +--- +--- a/arch/powerpc/platforms/pseries/iommu.c ++++ b/arch/powerpc/platforms/pseries/iommu.c +@@ -25,6 +25,7 @@ + #include + #include + #include ++#include + #include + #include + #include +@@ -206,7 +207,13 @@ static int tce_build_pSeriesLP(unsigned + return ret; + } + +-static DEFINE_PER_CPU(__be64 *, tce_page); ++struct tce_page { ++ __be64 * page; ++ local_lock_t lock; ++}; ++static DEFINE_PER_CPU(struct tce_page, tce_page) = { ++ .lock = INIT_LOCAL_LOCK(lock), ++}; + + static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum, + long npages, unsigned long uaddr, +@@ -229,9 +236,10 @@ static int tce_buildmulti_pSeriesLP(stru + direction, attrs); + } + +- local_irq_save(flags); /* to protect tcep and the page behind it */ ++ /* to protect tcep and the page behind it */ ++ local_lock_irqsave(&tce_page.lock, flags); + +- tcep = __this_cpu_read(tce_page); ++ tcep = __this_cpu_read(tce_page.page); + + /* This is safe to do since interrupts are off when we're called + * from iommu_alloc{,_sg}() +@@ -240,12 +248,12 @@ static int tce_buildmulti_pSeriesLP(stru + tcep = (__be64 *)__get_free_page(GFP_ATOMIC); + /* If allocation fails, fall back to the loop implementation */ + if (!tcep) { +- local_irq_restore(flags); ++ local_unlock_irqrestore(&tce_page.lock, flags); + return tce_build_pSeriesLP(tbl->it_index, tcenum, + tceshift, + npages, uaddr, direction, attrs); + } +- __this_cpu_write(tce_page, tcep); ++ __this_cpu_write(tce_page.page, tcep); + } + + rpn = __pa(uaddr) >> tceshift; +@@ -275,7 +283,7 @@ static int tce_buildmulti_pSeriesLP(stru + tcenum += limit; + } while (npages > 0 && !rc); + +- local_irq_restore(flags); ++ local_unlock_irqrestore(&tce_page.lock, flags); + + if (unlikely(rc == H_NOT_ENOUGH_RESOURCES)) { + ret = (int)rc; +@@ -459,16 +467,17 @@ static int tce_setrange_multi_pSeriesLP( + DMA_BIDIRECTIONAL, 0); + } + +- local_irq_disable(); /* to protect tcep and the page behind it */ +- tcep = __this_cpu_read(tce_page); ++ /* to protect tcep and the page behind it */ ++ local_lock_irq(&tce_page.lock); ++ tcep = __this_cpu_read(tce_page.page); + + if (!tcep) { + tcep = (__be64 *)__get_free_page(GFP_ATOMIC); + if (!tcep) { +- local_irq_enable(); ++ local_unlock_irq(&tce_page.lock); + return -ENOMEM; + } +- __this_cpu_write(tce_page, tcep); ++ __this_cpu_write(tce_page.page, tcep); + } + + proto_tce = TCE_PCI_READ | TCE_PCI_WRITE; +@@ -511,7 +520,7 @@ static int tce_setrange_multi_pSeriesLP( + + /* error cleanup: caller will clear whole range */ + +- local_irq_enable(); ++ local_unlock_irq(&tce_page.lock); + return rc; + } + diff --git a/debian/patches-rt/powerpc_stackprotector__work_around_stack-guard_init_from_atomic.patch b/debian/patches-rt/powerpc_stackprotector__work_around_stack-guard_init_from_atomic.patch new file mode 100644 index 000000000..c8994ca9d --- /dev/null +++ b/debian/patches-rt/powerpc_stackprotector__work_around_stack-guard_init_from_atomic.patch @@ -0,0 +1,37 @@ +Subject: powerpc/stackprotector: work around stack-guard init from atomic +From: Sebastian Andrzej Siewior +Date: Tue Mar 26 18:31:29 2019 +0100 +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +From: Sebastian Andrzej Siewior + +This is invoked from the secondary CPU in atomic context. On x86 we use +tsc instead. On Power we XOR it against mftb() so lets use stack address +as the initial value. + +Cc: stable-rt@vger.kernel.org +Signed-off-by: Sebastian Andrzej Siewior +Signed-off-by: Thomas Gleixner + + +--- + arch/powerpc/include/asm/stackprotector.h | 7 ++++++- + 1 file changed, 6 insertions(+), 1 deletion(-) +--- +--- a/arch/powerpc/include/asm/stackprotector.h ++++ b/arch/powerpc/include/asm/stackprotector.h +@@ -19,8 +19,13 @@ + */ + static __always_inline void boot_init_stack_canary(void) + { +- unsigned long canary = get_random_canary(); ++ unsigned long canary; + ++#ifndef CONFIG_PREEMPT_RT ++ canary = get_random_canary(); ++#else ++ canary = ((unsigned long)&canary) & CANARY_MASK; ++#endif + current->stack_canary = canary; + #ifdef CONFIG_PPC64 + get_paca()->canary = canary; diff --git a/debian/patches-rt/preempt-Put-preempt_enable-within-an-instrumentation.patch b/debian/patches-rt/preempt-Put-preempt_enable-within-an-instrumentation.patch new file mode 100644 index 000000000..beddd4726 --- /dev/null +++ b/debian/patches-rt/preempt-Put-preempt_enable-within-an-instrumentation.patch @@ -0,0 +1,47 @@ +From: Sebastian Andrzej Siewior +Date: Wed, 8 Mar 2023 16:29:38 +0100 +Subject: [PATCH] preempt: Put preempt_enable() within an instrumentation*() + section. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Callers of preempt_enable() can be within an noinstr section leading to: +| vmlinux.o: warning: objtool: native_sched_clock+0x97: call to preempt_schedule_notrace_thunk() leaves .noinstr.text section +| vmlinux.o: warning: objtool: kvm_clock_read+0x22: call to preempt_schedule_notrace_thunk() leaves .noinstr.text section +| vmlinux.o: warning: objtool: local_clock+0xb4: call to preempt_schedule_notrace_thunk() leaves .noinstr.text section +| vmlinux.o: warning: objtool: enter_from_user_mode+0xea: call to preempt_schedule_thunk() leaves .noinstr.text section +| vmlinux.o: warning: objtool: syscall_enter_from_user_mode+0x140: call to preempt_schedule_thunk() leaves .noinstr.text section +| vmlinux.o: warning: objtool: syscall_enter_from_user_mode_prepare+0xf2: call to preempt_schedule_thunk() leaves .noinstr.text section +| vmlinux.o: warning: objtool: irqentry_enter_from_user_mode+0xea: call to preempt_schedule_thunk() leaves .noinstr.text section + +Signed-off-by: Sebastian Andrzej Siewior +Link: https://lore.kernel.org/r/20230309072724.3F6zRkvw@linutronix.de +--- + include/linux/preempt.h | 10 ++++++++-- + 1 file changed, 8 insertions(+), 2 deletions(-) + +--- a/include/linux/preempt.h ++++ b/include/linux/preempt.h +@@ -230,15 +230,21 @@ do { \ + #define preempt_enable() \ + do { \ + barrier(); \ +- if (unlikely(preempt_count_dec_and_test())) \ ++ if (unlikely(preempt_count_dec_and_test())) { \ ++ instrumentation_begin(); \ + __preempt_schedule(); \ ++ instrumentation_end(); \ ++ } \ + } while (0) + + #define preempt_enable_notrace() \ + do { \ + barrier(); \ +- if (unlikely(__preempt_count_dec_and_test())) \ ++ if (unlikely(__preempt_count_dec_and_test())) { \ ++ instrumentation_begin(); \ + __preempt_schedule_notrace(); \ ++ instrumentation_end(); \ ++ } \ + } while (0) + + #define preempt_check_resched() \ diff --git a/debian/patches-rt/rcutorture-Also-force-sched-priority-to-timersd-on-b.patch b/debian/patches-rt/rcutorture-Also-force-sched-priority-to-timersd-on-b.patch new file mode 100644 index 000000000..a75971478 --- /dev/null +++ b/debian/patches-rt/rcutorture-Also-force-sched-priority-to-timersd-on-b.patch @@ -0,0 +1,71 @@ +From: Frederic Weisbecker +Date: Tue, 5 Apr 2022 03:07:51 +0200 +Subject: [PATCH] rcutorture: Also force sched priority to timersd on + boosting test. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +ksoftirqd is statically boosted to the priority level right above the +one of rcu_torture_boost() so that timers, which torture readers rely on, +get a chance to run while rcu_torture_boost() is polling. + +However timers processing got split from ksoftirqd into their own kthread +(timersd) that isn't boosted. It has the same SCHED_FIFO low prio as +rcu_torture_boost() and therefore timers can't preempt it and may +starve. + +The issue can be triggered in practice on v5.17.1-rt17 using: + + ./kvm.sh --allcpus --configs TREE04 --duration 10m --kconfig "CONFIG_EXPERT=y CONFIG_PREEMPT_RT=y" + +Fix this with statically boosting timersd just like is done with +ksoftirqd in commit + ea6d962e80b61 ("rcutorture: Judge RCU priority boosting on grace periods, not callbacks") + +Suggested-by: Mel Gorman +Cc: Sebastian Andrzej Siewior +Cc: Thomas Gleixner +Signed-off-by: Frederic Weisbecker +Link: https://lkml.kernel.org/r/20220405010752.1347437-1-frederic@kernel.org +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/interrupt.h | 1 + + kernel/rcu/rcutorture.c | 6 ++++++ + kernel/softirq.c | 2 +- + 3 files changed, 8 insertions(+), 1 deletion(-) + +--- a/include/linux/interrupt.h ++++ b/include/linux/interrupt.h +@@ -610,6 +610,7 @@ extern void raise_softirq_irqoff(unsigne + extern void raise_softirq(unsigned int nr); + + #ifdef CONFIG_PREEMPT_RT ++DECLARE_PER_CPU(struct task_struct *, timersd); + extern void raise_timer_softirq(void); + extern void raise_hrtimer_softirq(void); + +--- a/kernel/rcu/rcutorture.c ++++ b/kernel/rcu/rcutorture.c +@@ -2408,6 +2408,12 @@ static int rcutorture_booster_init(unsig + WARN_ON_ONCE(!t); + sp.sched_priority = 2; + sched_setscheduler_nocheck(t, SCHED_FIFO, &sp); ++#ifdef CONFIG_PREEMPT_RT ++ t = per_cpu(timersd, cpu); ++ WARN_ON_ONCE(!t); ++ sp.sched_priority = 2; ++ sched_setscheduler_nocheck(t, SCHED_FIFO, &sp); ++#endif + } + + /* Don't allow time recalculation while creating a new task. */ +--- a/kernel/softirq.c ++++ b/kernel/softirq.c +@@ -620,7 +620,7 @@ static inline void tick_irq_exit(void) + } + + #ifdef CONFIG_PREEMPT_RT +-static DEFINE_PER_CPU(struct task_struct *, timersd); ++DEFINE_PER_CPU(struct task_struct *, timersd); + static DEFINE_PER_CPU(unsigned long, pending_timer_softirq); + + static unsigned int local_pending_timers(void) diff --git a/debian/patches-rt/riscv-add-PREEMPT_AUTO-support.patch b/debian/patches-rt/riscv-add-PREEMPT_AUTO-support.patch new file mode 100644 index 000000000..60c3bf3aa --- /dev/null +++ b/debian/patches-rt/riscv-add-PREEMPT_AUTO-support.patch @@ -0,0 +1,44 @@ +From: Jisheng Zhang +Date: Tue, 31 Oct 2023 22:35:20 +0800 +Subject: [PATCH] riscv: add PREEMPT_AUTO support +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +riscv has switched to GENERIC_ENTRY, so adding PREEMPT_AUTO is as simple +as adding TIF_ARCH_RESCHED_LAZY related definitions and enabling +HAVE_PREEMPT_AUTO. + +Signed-off-by: Jisheng Zhang +Signed-off-by: Sebastian Andrzej Siewior +--- + arch/riscv/Kconfig | 1 + + arch/riscv/include/asm/thread_info.h | 2 ++ + 2 files changed, 3 insertions(+) + +--- a/arch/riscv/Kconfig ++++ b/arch/riscv/Kconfig +@@ -135,6 +135,7 @@ config RISCV + select HAVE_PERF_USER_STACK_DUMP + select HAVE_POSIX_CPU_TIMERS_TASK_WORK + select HAVE_PREEMPT_DYNAMIC_KEY if !XIP_KERNEL ++ select HAVE_PREEMPT_AUTO + select HAVE_REGS_AND_STACK_ACCESS_API + select HAVE_RETHOOK if !XIP_KERNEL + select HAVE_RSEQ +--- a/arch/riscv/include/asm/thread_info.h ++++ b/arch/riscv/include/asm/thread_info.h +@@ -82,6 +82,7 @@ int arch_dup_task_struct(struct task_str + * - pending work-to-be-done flags are in lowest half-word + * - other flags in upper half-word(s) + */ ++#define TIF_ARCH_RESCHED_LAZY 0 /* Lazy rescheduling */ + #define TIF_NOTIFY_RESUME 1 /* callback before returning to user */ + #define TIF_SIGPENDING 2 /* signal pending */ + #define TIF_NEED_RESCHED 3 /* rescheduling necessary */ +@@ -96,6 +97,7 @@ int arch_dup_task_struct(struct task_str + #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) + #define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL) + #define _TIF_UPROBE (1 << TIF_UPROBE) ++#define _TIF_ARCH_RESCHED_LAZY (1 << TIF_ARCH_RESCHED_LAZY) + + #define _TIF_WORK_MASK \ + (_TIF_NOTIFY_RESUME | _TIF_SIGPENDING | _TIF_NEED_RESCHED | \ diff --git a/debian/patches-rt/riscv-allow-to-enable-RT.patch b/debian/patches-rt/riscv-allow-to-enable-RT.patch new file mode 100644 index 000000000..66fcfc8e7 --- /dev/null +++ b/debian/patches-rt/riscv-allow-to-enable-RT.patch @@ -0,0 +1,23 @@ +From: Jisheng Zhang +Date: Tue, 31 Oct 2023 22:35:21 +0800 +Subject: [PATCH] riscv: allow to enable RT +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Now, it's ready to enable RT on riscv. + +Signed-off-by: Jisheng Zhang +Signed-off-by: Sebastian Andrzej Siewior +--- + arch/riscv/Kconfig | 1 + + 1 file changed, 1 insertion(+) + +--- a/arch/riscv/Kconfig ++++ b/arch/riscv/Kconfig +@@ -48,6 +48,7 @@ config RISCV + select ARCH_SUPPORTS_HUGETLBFS if MMU + select ARCH_SUPPORTS_PAGE_TABLE_CHECK if MMU + select ARCH_SUPPORTS_PER_VMA_LOCK if MMU ++ select ARCH_SUPPORTS_RT + select ARCH_USE_MEMTEST + select ARCH_USE_QUEUED_RWLOCKS + select ARCH_USES_CFI_TRAPS if CFI_CLANG diff --git a/debian/patches-rt/sched-rt-Don-t-try-push-tasks-if-there-are-none.patch b/debian/patches-rt/sched-rt-Don-t-try-push-tasks-if-there-are-none.patch new file mode 100644 index 000000000..01e19e8fc --- /dev/null +++ b/debian/patches-rt/sched-rt-Don-t-try-push-tasks-if-there-are-none.patch @@ -0,0 +1,58 @@ +From: Sebastian Andrzej Siewior +Date: Tue, 1 Aug 2023 17:26:48 +0200 +Subject: [PATCH] sched/rt: Don't try push tasks if there are none. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +I have a RT task X at a high priority and cyclictest on each CPU with +lower priority than X's. If X is active and each CPU wakes their own +cylictest thread then it ends in a longer rto_push storm. +A random CPU determines via balance_rt() that the CPU on which X is +running needs to push tasks. X has the highest priority, cyclictest is +next in line so there is nothing that can be done since the task with +the higher priority is not touched. + +tell_cpu_to_push() increments rto_loop_next and schedules +rto_push_irq_work_func() on X's CPU. The other CPUs also increment the +loop counter and do the same. Once rto_push_irq_work_func() is active it +does nothing because it has _no_ pushable tasks on its runqueue. Then +checks rto_next_cpu() and decides to queue irq_work on the local CPU +because another CPU requested a push by incrementing the counter. + +I have traces where ~30 CPUs request this ~3 times each before it +finally ends. This greatly increases X's runtime while X isn't making +much progress. + +Teach rto_next_cpu() to only return CPUs which also have tasks on their +runqueue which can be pushed away. This does not reduce the +tell_cpu_to_push() invocations (rto_loop_next counter increments) but +reduces the amount of issued rto_push_irq_work_func() if nothing can be +done. As the result the overloaded CPU is blocked less often. + +There are still cases where the "same job" is repeated several times +(for instance the current CPU needs to resched but didn't yet because +the irq-work is repeated a few times and so the old task remains on the +CPU) but the majority of request end in tell_cpu_to_push() before an IPI +is issued. + +Reviewed-by: "Steven Rostedt (Google)" +Link: https://lore.kernel.org/r/20230801152648._y603AS_@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/sched/rt.c | 5 ++++- + 1 file changed, 4 insertions(+), 1 deletion(-) + +--- a/kernel/sched/rt.c ++++ b/kernel/sched/rt.c +@@ -2249,8 +2249,11 @@ static int rto_next_cpu(struct root_doma + + rd->rto_cpu = cpu; + +- if (cpu < nr_cpu_ids) ++ if (cpu < nr_cpu_ids) { ++ if (!has_pushable_tasks(cpu_rq(cpu))) ++ continue; + return cpu; ++ } + + rd->rto_cpu = -1; + diff --git a/debian/patches-rt/series b/debian/patches-rt/series new file mode 100644 index 000000000..9269d7464 --- /dev/null +++ b/debian/patches-rt/series @@ -0,0 +1,255 @@ +# Applied upstream + +########################################################################### +# Posted and applied +########################################################################### + +# signal_x86__Delay_calling_signals_in_atomic.patch + +########################################################################### +# Posted +########################################################################### +0001-sched-Constrain-locks-in-sched_submit_work.patch +0002-locking-rtmutex-Avoid-unconditional-slowpath-for-DEB.patch +0003-sched-Extract-__schedule_loop.patch +0004-sched-Provide-rt_mutex-specific-scheduler-helpers.patch +0005-locking-rtmutex-Use-rt_mutex-specific-scheduler-help.patch +0006-locking-rtmutex-Add-a-lockdep-assert-to-catch-potent.patch +0007-futex-pi-Fix-recursive-rt_mutex-waiter-state.patch + +# Hacks to get ptrace to work. +0001-signal-Add-proper-comment-about-the-preempt-disable-.patch +0002-signal-Don-t-disable-preemption-in-ptrace_stop-on-PR.patch + +# DRM AMD GPU +0001-drm-amd-display-Remove-migrate_en-dis-from-dc_fpu_be.patch +0002-drm-amd-display-Simplify-the-per-CPU-usage.patch +0003-drm-amd-display-Add-a-warning-if-the-FPU-is-used-out.patch +0004-drm-amd-display-Move-the-memory-allocation-out-of-dc.patch +0005-drm-amd-display-Move-the-memory-allocation-out-of-dc.patch + +########################################################################### +# Post +########################################################################### +net-Avoid-the-IPI-to-free-the.patch + +########################################################################### +# X86: +########################################################################### +x86__Allow_to_enable_RT.patch +x86__Enable_RT_also_on_32bit.patch + +########################################################################### +# For later, not essencial +########################################################################### +# Posted +sched-rt-Don-t-try-push-tasks-if-there-are-none.patch + +# Needs discussion first. +softirq-Use-a-dedicated-thread-for-timer-wakeups.patch +rcutorture-Also-force-sched-priority-to-timersd-on-b.patch +tick-Fix-timer-storm-since-introduction-of-timersd.patch +softirq-Wake-ktimers-thread-also-in-softirq.patch +zram-Replace-bit-spinlocks-with-spinlock_t-for-PREEM.patch +preempt-Put-preempt_enable-within-an-instrumentation.patch + +# Sched +0001-sched-core-Provide-a-method-to-check-if-a-task-is-PI.patch +0002-softirq-Add-function-to-preempt-serving-softirqs.patch +0003-time-Allow-to-preempt-after-a-callback.patch + +########################################################################### +# John's printk queue +########################################################################### +0002-serial-core-Use-lock-wrappers.patch +0003-serial-21285-Use-port-lock-wrappers.patch +0004-serial-8250_aspeed_vuart-Use-port-lock-wrappers.patch +0005-serial-8250_bcm7271-Use-port-lock-wrappers.patch +0006-serial-8250-Use-port-lock-wrappers.patch +0007-serial-8250_dma-Use-port-lock-wrappers.patch +0008-serial-8250_dw-Use-port-lock-wrappers.patch +0009-serial-8250_exar-Use-port-lock-wrappers.patch +0010-serial-8250_fsl-Use-port-lock-wrappers.patch +0011-serial-8250_mtk-Use-port-lock-wrappers.patch +0012-serial-8250_omap-Use-port-lock-wrappers.patch +0013-serial-8250_pci1xxxx-Use-port-lock-wrappers.patch +0014-serial-altera_jtaguart-Use-port-lock-wrappers.patch +0015-serial-altera_uart-Use-port-lock-wrappers.patch +0016-serial-amba-pl010-Use-port-lock-wrappers.patch +0017-serial-amba-pl011-Use-port-lock-wrappers.patch +0018-serial-apb-Use-port-lock-wrappers.patch +0019-serial-ar933x-Use-port-lock-wrappers.patch +0020-serial-arc_uart-Use-port-lock-wrappers.patch +0021-serial-atmel-Use-port-lock-wrappers.patch +0022-serial-bcm63xx-uart-Use-port-lock-wrappers.patch +0023-serial-cpm_uart-Use-port-lock-wrappers.patch +0024-serial-digicolor-Use-port-lock-wrappers.patch +0025-serial-dz-Use-port-lock-wrappers.patch +0026-serial-linflexuart-Use-port-lock-wrappers.patch +0027-serial-fsl_lpuart-Use-port-lock-wrappers.patch +0028-serial-icom-Use-port-lock-wrappers.patch +0029-serial-imx-Use-port-lock-wrappers.patch +0030-serial-ip22zilog-Use-port-lock-wrappers.patch +0031-serial-jsm-Use-port-lock-wrappers.patch +0032-serial-liteuart-Use-port-lock-wrappers.patch +0033-serial-lpc32xx_hs-Use-port-lock-wrappers.patch +0034-serial-ma35d1-Use-port-lock-wrappers.patch +0035-serial-mcf-Use-port-lock-wrappers.patch +0036-serial-men_z135_uart-Use-port-lock-wrappers.patch +0037-serial-meson-Use-port-lock-wrappers.patch +0038-serial-milbeaut_usio-Use-port-lock-wrappers.patch +0039-serial-mpc52xx-Use-port-lock-wrappers.patch +0040-serial-mps2-uart-Use-port-lock-wrappers.patch +0041-serial-msm-Use-port-lock-wrappers.patch +0042-serial-mvebu-uart-Use-port-lock-wrappers.patch +0043-serial-omap-Use-port-lock-wrappers.patch +0044-serial-owl-Use-port-lock-wrappers.patch +0045-serial-pch-Use-port-lock-wrappers.patch +0046-serial-pic32-Use-port-lock-wrappers.patch +0047-serial-pmac_zilog-Use-port-lock-wrappers.patch +0048-serial-pxa-Use-port-lock-wrappers.patch +0049-serial-qcom-geni-Use-port-lock-wrappers.patch +0050-serial-rda-Use-port-lock-wrappers.patch +0051-serial-rp2-Use-port-lock-wrappers.patch +0052-serial-sa1100-Use-port-lock-wrappers.patch +0053-serial-samsung_tty-Use-port-lock-wrappers.patch +0054-serial-sb1250-duart-Use-port-lock-wrappers.patch +0056-serial-tegra-Use-port-lock-wrappers.patch +0057-serial-core-Use-port-lock-wrappers.patch +0058-serial-mctrl_gpio-Use-port-lock-wrappers.patch +0059-serial-txx9-Use-port-lock-wrappers.patch +0060-serial-sh-sci-Use-port-lock-wrappers.patch +0061-serial-sifive-Use-port-lock-wrappers.patch +0062-serial-sprd-Use-port-lock-wrappers.patch +0063-serial-st-asc-Use-port-lock-wrappers.patch +0064-serial-stm32-Use-port-lock-wrappers.patch +0065-serial-sunhv-Use-port-lock-wrappers.patch +0066-serial-sunplus-uart-Use-port-lock-wrappers.patch +0067-serial-sunsab-Use-port-lock-wrappers.patch +0068-serial-sunsu-Use-port-lock-wrappers.patch +0069-serial-sunzilog-Use-port-lock-wrappers.patch +0070-serial-timbuart-Use-port-lock-wrappers.patch +0071-serial-uartlite-Use-port-lock-wrappers.patch +0072-serial-ucc_uart-Use-port-lock-wrappers.patch +0073-serial-vt8500-Use-port-lock-wrappers.patch +0074-serial-xilinx_uartps-Use-port-lock-wrappers.patch +0075-printk-Add-non-BKL-nbcon-console-basic-infrastructur.patch +0076-printk-nbcon-Add-acquire-release-logic.patch +0077-printk-Make-static-printk-buffers-available-to-nbcon.patch +0078-printk-nbcon-Add-buffer-management.patch +0079-printk-nbcon-Add-ownership-state-functions.patch +0080-printk-nbcon-Add-sequence-handling.patch +0081-printk-nbcon-Add-emit-function-and-callback-function.patch +0082-printk-nbcon-Allow-drivers-to-mark-unsafe-regions-an.patch +0083-printk-fix-illegal-pbufs-access-for-CONFIG_PRINTK.patch +0084-printk-Reduce-pr_flush-pooling-time.patch +0085-printk-nbcon-Relocate-32bit-seq-macros.patch +0086-printk-Adjust-mapping-for-32bit-seq-macros.patch +0087-printk-Use-prb_first_seq-as-base-for-32bit-seq-macro.patch +0088-printk-ringbuffer-Do-not-skip-non-finalized-records-.patch +0089-printk-ringbuffer-Clarify-special-lpos-values.patch +0090-printk-For-suppress_panic_printk-check-for-other-CPU.patch +0091-printk-Add-this_cpu_in_panic.patch +0092-printk-ringbuffer-Cleanup-reader-terminology.patch +0093-printk-Wait-for-all-reserved-records-with-pr_flush.patch +0094-printk-ringbuffer-Skip-non-finalized-records-in-pani.patch +0095-printk-ringbuffer-Consider-committed-as-finalized-in.patch +0096-printk-Disable-passing-console-lock-owner-completely.patch +0097-printk-Avoid-non-panic-CPUs-writing-to-ringbuffer.patch +0098-panic-Flush-kernel-log-buffer-at-the-end.patch +0099-printk-Consider-nbcon-boot-consoles-on-seq-init.patch +0100-printk-Add-sparse-notation-to-console_srcu-locking.patch +0101-printk-nbcon-Ensure-ownership-release-on-failed-emit.patch +0102-printk-Check-printk_deferred_enter-_exit-usage.patch +0103-printk-nbcon-Implement-processing-in-port-lock-wrapp.patch +0104-printk-nbcon-Add-driver_enter-driver_exit-console-ca.patch +0105-printk-Make-console_is_usable-available-to-nbcon.patch +0106-printk-Let-console_is_usable-handle-nbcon.patch +0107-printk-Add-flags-argument-for-console_is_usable.patch +0108-printk-nbcon-Provide-function-to-flush-using-write_a.patch +0109-printk-Track-registered-boot-consoles.patch +0110-printk-nbcon-Use-nbcon-consoles-in-console_flush_all.patch +0111-printk-nbcon-Assign-priority-based-on-CPU-state.patch +0112-printk-nbcon-Add-unsafe-flushing-on-panic.patch +0113-printk-Avoid-console_lock-dance-if-no-legacy-or-boot.patch +0114-printk-Track-nbcon-consoles.patch +0115-printk-Coordinate-direct-printing-in-panic.patch +0116-printk-nbcon-Implement-emergency-sections.patch +0117-panic-Mark-emergency-section-in-warn.patch +0118-panic-Mark-emergency-section-in-oops.patch +0119-rcu-Mark-emergency-section-in-rcu-stalls.patch +0120-lockdep-Mark-emergency-section-in-lockdep-splats.patch +0121-printk-nbcon-Introduce-printing-kthreads.patch +0122-printk-Atomic-print-in-printk-context-on-shutdown.patch +0123-printk-nbcon-Add-context-to-console_is_usable.patch +0124-printk-nbcon-Add-printer-thread-wakeups.patch +0125-printk-nbcon-Stop-threads-on-shutdown-reboot.patch +0126-printk-nbcon-Start-printing-threads.patch +0127-proc-Add-nbcon-support-for-proc-consoles.patch +0128-tty-sysfs-Add-nbcon-support-for-active.patch +0129-printk-nbcon-Provide-function-to-reacquire-ownership.patch +0130-serial-core-Provide-low-level-functions-to-port-lock.patch +0131-serial-8250-Switch-to-nbcon-console.patch +0132-printk-Add-kthread-for-all-legacy-consoles.patch +0133-serial-8250-revert-drop-lockdep-annotation-from-seri.patch +0134-printk-Avoid-false-positive-lockdep-report-for-legac.patch + +########################################################################### +# DRM: +########################################################################### +0003-drm-i915-Use-preempt_disable-enable_rt-where-recomme.patch +0004-drm-i915-Don-t-disable-interrupts-on-PREEMPT_RT-duri.patch +0005-drm-i915-Don-t-check-for-atomic-context-on-PREEMPT_R.patch +0006-drm-i915-Disable-tracing-points-on-PREEMPT_RT.patch +0007-drm-i915-skip-DRM_I915_LOW_LEVEL_TRACEPOINTS-with-NO.patch +0008-drm-i915-gt-Queue-and-wait-for-the-irq_work-item.patch +0009-drm-i915-gt-Use-spin_lock_irq-instead-of-local_irq_d.patch +0010-drm-i915-Drop-the-irqs_disabled-check.patch +drm-i915-Do-not-disable-preemption-for-resets.patch +drm-i915-guc-Consider-also-RCU-depth-in-busy-loop.patch +Revert-drm-i915-Depend-on-PREEMPT_RT.patch + +########################################################################### +# Lazy preemption +########################################################################### +PREEMPT_AUTO.patch + +########################################################################### +# ARM/ARM64 +########################################################################### +0001-arm-Disable-jump-label-on-PREEMPT_RT.patch +ARM__enable_irq_in_translation_section_permission_fault_handlers.patch +# arm64-signal-Use-ARCH_RT_DELAYS_SIGNAL_SEND.patch +tty_serial_omap__Make_the_locking_RT_aware.patch +tty_serial_pl011__Make_the_locking_work_on_RT.patch +0001-ARM-vfp-Provide-vfp_lock-for-VFP-locking.patch +0002-ARM-vfp-Use-vfp_lock-in-vfp_sync_hwstate.patch +0003-ARM-vfp-Use-vfp_lock-in-vfp_support_entry.patch +0004-ARM-vfp-Move-sending-signals-outside-of-vfp_lock-ed-.patch +ARM__Allow_to_enable_RT.patch +ARM64__Allow_to_enable_RT.patch + +########################################################################### +# POWERPC +########################################################################### +powerpc__traps__Use_PREEMPT_RT.patch +powerpc_pseries_iommu__Use_a_locallock_instead_local_irq_save.patch +powerpc-pseries-Select-the-generic-memory-allocator.patch +powerpc_kvm__Disable_in-kernel_MPIC_emulation_for_PREEMPT_RT.patch +powerpc_stackprotector__work_around_stack-guard_init_from_atomic.patch +POWERPC__Allow_to_enable_RT.patch + +########################################################################### +# RISC-V +########################################################################### +#RISC-V-Probe-misaligned-access-speed-in-parallel.patch +riscv-add-PREEMPT_AUTO-support.patch +riscv-allow-to-enable-RT.patch + +# Sysfs file vs uname() -v +sysfs__Add__sys_kernel_realtime_entry.patch + +########################################################################### +# RT release version +########################################################################### +Add_localversion_for_-RT_release.patch diff --git a/debian/patches-rt/softirq-Use-a-dedicated-thread-for-timer-wakeups.patch b/debian/patches-rt/softirq-Use-a-dedicated-thread-for-timer-wakeups.patch new file mode 100644 index 000000000..949ff6da7 --- /dev/null +++ b/debian/patches-rt/softirq-Use-a-dedicated-thread-for-timer-wakeups.patch @@ -0,0 +1,222 @@ +From: Sebastian Andrzej Siewior +Date: Wed, 1 Dec 2021 17:41:09 +0100 +Subject: [PATCH] softirq: Use a dedicated thread for timer wakeups. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +A timer/hrtimer softirq is raised in-IRQ context. With threaded +interrupts enabled or on PREEMPT_RT this leads to waking the ksoftirqd +for the processing of the softirq. +Once the ksoftirqd is marked as pending (or is running) it will collect +all raised softirqs. This in turn means that a softirq which would have +been processed at the end of the threaded interrupt, which runs at an +elevated priority, is now moved to ksoftirqd which runs at SCHED_OTHER +priority and competes with every regular task for CPU resources. +This introduces long delays on heavy loaded systems and is not desired +especially if the system is not overloaded by the softirqs. + +Split the TIMER_SOFTIRQ and HRTIMER_SOFTIRQ processing into a dedicated +timers thread and let it run at the lowest SCHED_FIFO priority. +RT tasks are are woken up from hardirq context so only timer_list timers +and hrtimers for "regular" tasks are processed here. The higher priority +ensures that wakeups are performed before scheduling SCHED_OTHER tasks. + +Using a dedicated variable to store the pending softirq bits values +ensure that the timer are not accidentally picked up by ksoftirqd and +other threaded interrupts. +It shouldn't be picked up by ksoftirqd since it runs at lower priority. +However if the timer bits are ORed while a threaded interrupt is +running, then the timer softirq would be performed at higher priority. +The new timer thread will block on the softirq lock before it starts +softirq work. This "race window" isn't closed because while timer thread +is performing the softirq it can get PI-boosted via the softirq lock by +a random force-threaded thread. +The timer thread can pick up pending softirqs from ksoftirqd but only +if the softirq load is high. It is not be desired that the picked up +softirqs are processed at SCHED_FIFO priority under high softirq load +but this can already happen by a PI-boost by a force-threaded interrupt. + +Reported-by: kernel test robot [ static timer_threads ] +Signed-off-by: Sebastian Andrzej Siewior +--- + include/linux/interrupt.h | 16 ++++++++ + kernel/softirq.c | 92 ++++++++++++++++++++++++++++++++++++++++++++-- + kernel/time/hrtimer.c | 4 +- + kernel/time/timer.c | 2 - + 4 files changed, 108 insertions(+), 6 deletions(-) + +--- a/include/linux/interrupt.h ++++ b/include/linux/interrupt.h +@@ -609,6 +609,22 @@ extern void __raise_softirq_irqoff(unsig + extern void raise_softirq_irqoff(unsigned int nr); + extern void raise_softirq(unsigned int nr); + ++#ifdef CONFIG_PREEMPT_RT ++extern void raise_timer_softirq(void); ++extern void raise_hrtimer_softirq(void); ++ ++#else ++static inline void raise_timer_softirq(void) ++{ ++ raise_softirq(TIMER_SOFTIRQ); ++} ++ ++static inline void raise_hrtimer_softirq(void) ++{ ++ raise_softirq_irqoff(HRTIMER_SOFTIRQ); ++} ++#endif ++ + DECLARE_PER_CPU(struct task_struct *, ksoftirqd); + + static inline struct task_struct *this_cpu_ksoftirqd(void) +--- a/kernel/softirq.c ++++ b/kernel/softirq.c +@@ -619,6 +619,29 @@ static inline void tick_irq_exit(void) + #endif + } + ++#ifdef CONFIG_PREEMPT_RT ++static DEFINE_PER_CPU(struct task_struct *, timersd); ++static DEFINE_PER_CPU(unsigned long, pending_timer_softirq); ++ ++static unsigned int local_pending_timers(void) ++{ ++ return __this_cpu_read(pending_timer_softirq); ++} ++ ++static void wake_timersd(void) ++{ ++ struct task_struct *tsk = __this_cpu_read(timersd); ++ ++ if (tsk) ++ wake_up_process(tsk); ++} ++ ++#else ++ ++static inline void wake_timersd(void) { } ++ ++#endif ++ + static inline void __irq_exit_rcu(void) + { + #ifndef __ARCH_IRQ_EXIT_IRQS_DISABLED +@@ -628,8 +651,13 @@ static inline void __irq_exit_rcu(void) + #endif + account_hardirq_exit(current); + preempt_count_sub(HARDIRQ_OFFSET); +- if (!in_interrupt() && local_softirq_pending()) +- invoke_softirq(); ++ if (!in_interrupt()) { ++ if (local_softirq_pending()) ++ invoke_softirq(); ++ ++ if (IS_ENABLED(CONFIG_PREEMPT_RT) && local_pending_timers()) ++ wake_timersd(); ++ } + + tick_irq_exit(); + } +@@ -963,12 +991,70 @@ static struct smp_hotplug_thread softirq + .thread_comm = "ksoftirqd/%u", + }; + ++#ifdef CONFIG_PREEMPT_RT ++static void timersd_setup(unsigned int cpu) ++{ ++ sched_set_fifo_low(current); ++} ++ ++static int timersd_should_run(unsigned int cpu) ++{ ++ return local_pending_timers(); ++} ++ ++static void run_timersd(unsigned int cpu) ++{ ++ unsigned int timer_si; ++ ++ ksoftirqd_run_begin(); ++ ++ timer_si = local_pending_timers(); ++ __this_cpu_write(pending_timer_softirq, 0); ++ or_softirq_pending(timer_si); ++ ++ __do_softirq(); ++ ++ ksoftirqd_run_end(); ++} ++ ++static void raise_ktimers_thread(unsigned int nr) ++{ ++ trace_softirq_raise(nr); ++ __this_cpu_or(pending_timer_softirq, 1 << nr); ++} ++ ++void raise_hrtimer_softirq(void) ++{ ++ raise_ktimers_thread(HRTIMER_SOFTIRQ); ++} ++ ++void raise_timer_softirq(void) ++{ ++ unsigned long flags; ++ ++ local_irq_save(flags); ++ raise_ktimers_thread(TIMER_SOFTIRQ); ++ wake_timersd(); ++ local_irq_restore(flags); ++} ++ ++static struct smp_hotplug_thread timer_threads = { ++ .store = &timersd, ++ .setup = timersd_setup, ++ .thread_should_run = timersd_should_run, ++ .thread_fn = run_timersd, ++ .thread_comm = "ktimers/%u", ++}; ++#endif ++ + static __init int spawn_ksoftirqd(void) + { + cpuhp_setup_state_nocalls(CPUHP_SOFTIRQ_DEAD, "softirq:dead", NULL, + takeover_tasklets); + BUG_ON(smpboot_register_percpu_thread(&softirq_threads)); +- ++#ifdef CONFIG_PREEMPT_RT ++ BUG_ON(smpboot_register_percpu_thread(&timer_threads)); ++#endif + return 0; + } + early_initcall(spawn_ksoftirqd); +--- a/kernel/time/hrtimer.c ++++ b/kernel/time/hrtimer.c +@@ -1808,7 +1808,7 @@ void hrtimer_interrupt(struct clock_even + if (!ktime_before(now, cpu_base->softirq_expires_next)) { + cpu_base->softirq_expires_next = KTIME_MAX; + cpu_base->softirq_activated = 1; +- raise_softirq_irqoff(HRTIMER_SOFTIRQ); ++ raise_hrtimer_softirq(); + } + + __hrtimer_run_queues(cpu_base, now, flags, HRTIMER_ACTIVE_HARD); +@@ -1921,7 +1921,7 @@ void hrtimer_run_queues(void) + if (!ktime_before(now, cpu_base->softirq_expires_next)) { + cpu_base->softirq_expires_next = KTIME_MAX; + cpu_base->softirq_activated = 1; +- raise_softirq_irqoff(HRTIMER_SOFTIRQ); ++ raise_hrtimer_softirq(); + } + + __hrtimer_run_queues(cpu_base, now, flags, HRTIMER_ACTIVE_HARD); +--- a/kernel/time/timer.c ++++ b/kernel/time/timer.c +@@ -2054,7 +2054,7 @@ static void run_local_timers(void) + if (time_before(jiffies, base->next_expiry)) + return; + } +- raise_softirq(TIMER_SOFTIRQ); ++ raise_timer_softirq(); + } + + /* diff --git a/debian/patches-rt/softirq-Wake-ktimers-thread-also-in-softirq.patch b/debian/patches-rt/softirq-Wake-ktimers-thread-also-in-softirq.patch new file mode 100644 index 000000000..21609fe20 --- /dev/null +++ b/debian/patches-rt/softirq-Wake-ktimers-thread-also-in-softirq.patch @@ -0,0 +1,44 @@ +From: Junxiao Chang +Date: Mon, 20 Feb 2023 09:12:20 +0100 +Subject: [PATCH] softirq: Wake ktimers thread also in softirq. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +If the hrtimer is raised while a softirq is processed then it does not +wake the corresponding ktimers thread. This is due to the optimisation in the +irq-exit path which is also used to wake the ktimers thread. For the other +softirqs, this is okay because the additional softirq bits will be handled by +the currently running softirq handler. +The timer related softirq bits are added to a different variable and rely on +the ktimers thread. +As a consuequence the wake up of ktimersd is delayed until the next timer tick. + +Always wake the ktimers thread if a timer related softirq is pending. + +Reported-by: Peh, Hock Zhang +Signed-off-by: Junxiao Chang +Signed-off-by: Sebastian Andrzej Siewior +--- + kernel/softirq.c | 11 +++++------ + 1 file changed, 5 insertions(+), 6 deletions(-) + +--- a/kernel/softirq.c ++++ b/kernel/softirq.c +@@ -646,13 +646,12 @@ static inline void __irq_exit_rcu(void) + #endif + account_hardirq_exit(current); + preempt_count_sub(HARDIRQ_OFFSET); +- if (!in_interrupt()) { +- if (local_softirq_pending()) +- invoke_softirq(); ++ if (!in_interrupt() && local_softirq_pending()) ++ invoke_softirq(); + +- if (IS_ENABLED(CONFIG_PREEMPT_RT) && local_pending_timers()) +- wake_timersd(); +- } ++ if (IS_ENABLED(CONFIG_PREEMPT_RT) && local_pending_timers() && ++ !(in_nmi() | in_hardirq())) ++ wake_timersd(); + + tick_irq_exit(); + } diff --git a/debian/patches-rt/sysfs__Add__sys_kernel_realtime_entry.patch b/debian/patches-rt/sysfs__Add__sys_kernel_realtime_entry.patch new file mode 100644 index 000000000..2e6928846 --- /dev/null +++ b/debian/patches-rt/sysfs__Add__sys_kernel_realtime_entry.patch @@ -0,0 +1,53 @@ +Subject: sysfs: Add /sys/kernel/realtime entry +From: Clark Williams +Date: Sat Jul 30 21:55:53 2011 -0500 +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +From: Clark Williams + +Add a /sys/kernel entry to indicate that the kernel is a +realtime kernel. + +Clark says that he needs this for udev rules, udev needs to evaluate +if its a PREEMPT_RT kernel a few thousand times and parsing uname +output is too slow or so. + +Are there better solutions? Should it exist and return 0 on !-rt? + +Signed-off-by: Clark Williams +Signed-off-by: Peter Zijlstra +Signed-off-by: Thomas Gleixner + + +--- + kernel/ksysfs.c | 12 ++++++++++++ + 1 file changed, 12 insertions(+) +--- +--- a/kernel/ksysfs.c ++++ b/kernel/ksysfs.c +@@ -179,6 +179,15 @@ KERNEL_ATTR_RO(crash_elfcorehdr_size); + + #endif /* CONFIG_CRASH_CORE */ + ++#if defined(CONFIG_PREEMPT_RT) ++static ssize_t realtime_show(struct kobject *kobj, ++ struct kobj_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "%d\n", 1); ++} ++KERNEL_ATTR_RO(realtime); ++#endif ++ + /* whether file capabilities are enabled */ + static ssize_t fscaps_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +@@ -275,6 +284,9 @@ static struct attribute * kernel_attrs[] + &rcu_expedited_attr.attr, + &rcu_normal_attr.attr, + #endif ++#ifdef CONFIG_PREEMPT_RT ++ &realtime_attr.attr, ++#endif + NULL + }; + diff --git a/debian/patches-rt/tick-Fix-timer-storm-since-introduction-of-timersd.patch b/debian/patches-rt/tick-Fix-timer-storm-since-introduction-of-timersd.patch new file mode 100644 index 000000000..874c7b3b3 --- /dev/null +++ b/debian/patches-rt/tick-Fix-timer-storm-since-introduction-of-timersd.patch @@ -0,0 +1,106 @@ +From: Frederic Weisbecker +Date: Tue, 5 Apr 2022 03:07:52 +0200 +Subject: [PATCH] tick: Fix timer storm since introduction of timersd +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +If timers are pending while the tick is reprogrammed on nohz_mode, the +next expiry is not armed to fire now, it is delayed one jiffy forward +instead so as not to raise an inextinguishable timer storm with such +scenario: + +1) IRQ triggers and queue a timer +2) ksoftirqd() is woken up +3) IRQ tail: timer is reprogrammed to fire now +4) IRQ exit +5) TIMER interrupt +6) goto 3) + +...all that until we finally reach ksoftirqd. + +Unfortunately we are checking the wrong softirq vector bitmask since +timersd kthread has split from ksoftirqd. Timers now have their own +vector state field that must be checked separately. As a result, the +old timer storm is back. This shows up early on boot with extremely long +initcalls: + + [ 333.004807] initcall dquot_init+0x0/0x111 returned 0 after 323822879 usecs + +and the cause is uncovered with the right trace events showing just +10 microseconds between ticks (~100 000 Hz): + +|swapper/-1 1dn.h111 60818582us : hrtimer_expire_entry: hrtimer=00000000e0ef0f6b function=tick_sched_timer now=60415486608 +|swapper/-1 1dn.h111 60818592us : hrtimer_expire_entry: hrtimer=00000000e0ef0f6b function=tick_sched_timer now=60415496082 +|swapper/-1 1dn.h111 60818601us : hrtimer_expire_entry: hrtimer=00000000e0ef0f6b function=tick_sched_timer now=60415505550 + +Fix this by checking the right timer vector state from the nohz code. + +Signed-off-by: Frederic Weisbecker +Cc: Mel Gorman +Cc: Sebastian Andrzej Siewior +Cc: Thomas Gleixner +Signed-off-by: Sebastian Andrzej Siewior +Link: https://lkml.kernel.org/r/20220405010752.1347437-2-frederic@kernel.org +--- + include/linux/interrupt.h | 12 ++++++++++++ + kernel/softirq.c | 7 +------ + kernel/time/tick-sched.c | 2 +- + 3 files changed, 14 insertions(+), 7 deletions(-) + +--- a/include/linux/interrupt.h ++++ b/include/linux/interrupt.h +@@ -611,9 +611,16 @@ extern void raise_softirq(unsigned int n + + #ifdef CONFIG_PREEMPT_RT + DECLARE_PER_CPU(struct task_struct *, timersd); ++DECLARE_PER_CPU(unsigned long, pending_timer_softirq); ++ + extern void raise_timer_softirq(void); + extern void raise_hrtimer_softirq(void); + ++static inline unsigned int local_pending_timers(void) ++{ ++ return __this_cpu_read(pending_timer_softirq); ++} ++ + #else + static inline void raise_timer_softirq(void) + { +@@ -624,6 +631,11 @@ static inline void raise_hrtimer_softirq + { + raise_softirq_irqoff(HRTIMER_SOFTIRQ); + } ++ ++static inline unsigned int local_pending_timers(void) ++{ ++ return local_softirq_pending(); ++} + #endif + + DECLARE_PER_CPU(struct task_struct *, ksoftirqd); +--- a/kernel/softirq.c ++++ b/kernel/softirq.c +@@ -621,12 +621,7 @@ static inline void tick_irq_exit(void) + + #ifdef CONFIG_PREEMPT_RT + DEFINE_PER_CPU(struct task_struct *, timersd); +-static DEFINE_PER_CPU(unsigned long, pending_timer_softirq); +- +-static unsigned int local_pending_timers(void) +-{ +- return __this_cpu_read(pending_timer_softirq); +-} ++DEFINE_PER_CPU(unsigned long, pending_timer_softirq); + + static void wake_timersd(void) + { +--- a/kernel/time/tick-sched.c ++++ b/kernel/time/tick-sched.c +@@ -795,7 +795,7 @@ static void tick_nohz_restart(struct tic + + static inline bool local_timer_softirq_pending(void) + { +- return local_softirq_pending() & BIT(TIMER_SOFTIRQ); ++ return local_pending_timers() & BIT(TIMER_SOFTIRQ); + } + + static ktime_t tick_nohz_next_event(struct tick_sched *ts, int cpu) diff --git a/debian/patches-rt/tty_serial_omap__Make_the_locking_RT_aware.patch b/debian/patches-rt/tty_serial_omap__Make_the_locking_RT_aware.patch new file mode 100644 index 000000000..89d744740 --- /dev/null +++ b/debian/patches-rt/tty_serial_omap__Make_the_locking_RT_aware.patch @@ -0,0 +1,47 @@ +Subject: tty/serial/omap: Make the locking RT aware +From: Thomas Gleixner +Date: Thu Jul 28 13:32:57 2011 +0200 +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +From: Thomas Gleixner + +The lock is a sleeping lock and local_irq_save() is not the +optimsation we are looking for. Redo it to make it work on -RT and +non-RT. + +Signed-off-by: Thomas Gleixner + + +--- + drivers/tty/serial/omap-serial.c | 12 ++++-------- + 1 file changed, 4 insertions(+), 8 deletions(-) +--- +--- a/drivers/tty/serial/omap-serial.c ++++ b/drivers/tty/serial/omap-serial.c +@@ -1212,13 +1212,10 @@ serial_omap_console_write(struct console + unsigned int ier; + int locked = 1; + +- local_irq_save(flags); +- if (up->port.sysrq) +- locked = 0; +- else if (oops_in_progress) +- locked = uart_port_trylock(&up->port); ++ if (up->port.sysrq || oops_in_progress) ++ locked = uart_port_trylock_irqsave(&up->port, &flags); + else +- uart_port_lock(&up->port); ++ uart_port_lock_irqsave(&up->port, &flags); + + /* + * First save the IER then disable the interrupts +@@ -1245,8 +1242,7 @@ serial_omap_console_write(struct console + check_modem_status(up); + + if (locked) +- uart_port_unlock(&up->port); +- local_irq_restore(flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static int __init diff --git a/debian/patches-rt/tty_serial_pl011__Make_the_locking_work_on_RT.patch b/debian/patches-rt/tty_serial_pl011__Make_the_locking_work_on_RT.patch new file mode 100644 index 000000000..32ff14fba --- /dev/null +++ b/debian/patches-rt/tty_serial_pl011__Make_the_locking_work_on_RT.patch @@ -0,0 +1,46 @@ +Subject: tty/serial/pl011: Make the locking work on RT +From: Thomas Gleixner +Date: Tue Jan 8 21:36:51 2013 +0100 +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +From: Thomas Gleixner + +The lock is a sleeping lock and local_irq_save() is not the optimsation +we are looking for. Redo it to make it work on -RT and non-RT. + +Signed-off-by: Thomas Gleixner + + +--- + drivers/tty/serial/amba-pl011.c | 12 ++++-------- + 1 file changed, 4 insertions(+), 8 deletions(-) +--- +--- a/drivers/tty/serial/amba-pl011.c ++++ b/drivers/tty/serial/amba-pl011.c +@@ -2332,13 +2332,10 @@ pl011_console_write(struct console *co, + + clk_enable(uap->clk); + +- local_irq_save(flags); +- if (uap->port.sysrq) +- locked = 0; +- else if (oops_in_progress) +- locked = uart_port_trylock(&uap->port); ++ if (uap->port.sysrq || oops_in_progress) ++ locked = uart_port_trylock_irqsave(&uap->port, &flags); + else +- uart_port_lock(&uap->port); ++ uart_port_lock_irqsave(&uap->port, &flags); + + /* + * First save the CR then disable the interrupts +@@ -2364,8 +2361,7 @@ pl011_console_write(struct console *co, + pl011_write(old_cr, uap, REG_CR); + + if (locked) +- uart_port_unlock(&uap->port); +- local_irq_restore(flags); ++ uart_port_unlock_irqrestore(&uap->port, flags); + + clk_disable(uap->clk); + } diff --git a/debian/patches-rt/x86__Allow_to_enable_RT.patch b/debian/patches-rt/x86__Allow_to_enable_RT.patch new file mode 100644 index 000000000..3fa433084 --- /dev/null +++ b/debian/patches-rt/x86__Allow_to_enable_RT.patch @@ -0,0 +1,27 @@ +Subject: x86: Allow to enable RT +From: Sebastian Andrzej Siewior +Date: Wed Aug 7 18:15:38 2019 +0200 +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +From: Sebastian Andrzej Siewior + +Allow to select RT. + +Signed-off-by: Sebastian Andrzej Siewior +Signed-off-by: Thomas Gleixner + + +--- + arch/x86/Kconfig | 1 + + 1 file changed, 1 insertion(+) +--- +--- a/arch/x86/Kconfig ++++ b/arch/x86/Kconfig +@@ -28,6 +28,7 @@ config X86_64 + select ARCH_HAS_GIGANTIC_PAGE + select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 + select ARCH_SUPPORTS_PER_VMA_LOCK ++ select ARCH_SUPPORTS_RT + select ARCH_USE_CMPXCHG_LOCKREF + select HAVE_ARCH_SOFT_DIRTY + select MODULES_USE_ELF_RELA diff --git a/debian/patches-rt/x86__Enable_RT_also_on_32bit.patch b/debian/patches-rt/x86__Enable_RT_also_on_32bit.patch new file mode 100644 index 000000000..3092b41ac --- /dev/null +++ b/debian/patches-rt/x86__Enable_RT_also_on_32bit.patch @@ -0,0 +1,33 @@ +Subject: x86: Enable RT also on 32bit +From: Sebastian Andrzej Siewior +Date: Thu Nov 7 17:49:20 2019 +0100 +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +From: Sebastian Andrzej Siewior + +Signed-off-by: Sebastian Andrzej Siewior +Signed-off-by: Thomas Gleixner + + +--- + arch/x86/Kconfig | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) +--- +--- a/arch/x86/Kconfig ++++ b/arch/x86/Kconfig +@@ -28,7 +28,6 @@ config X86_64 + select ARCH_HAS_GIGANTIC_PAGE + select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 + select ARCH_SUPPORTS_PER_VMA_LOCK +- select ARCH_SUPPORTS_RT + select ARCH_USE_CMPXCHG_LOCKREF + select HAVE_ARCH_SOFT_DIRTY + select MODULES_USE_ELF_RELA +@@ -118,6 +117,7 @@ config X86 + select ARCH_USES_CFI_TRAPS if X86_64 && CFI_CLANG + select ARCH_SUPPORTS_LTO_CLANG + select ARCH_SUPPORTS_LTO_CLANG_THIN ++ select ARCH_SUPPORTS_RT + select ARCH_USE_BUILTIN_BSWAP + select ARCH_USE_MEMTEST + select ARCH_USE_QUEUED_RWLOCKS diff --git a/debian/patches-rt/zram-Replace-bit-spinlocks-with-spinlock_t-for-PREEM.patch b/debian/patches-rt/zram-Replace-bit-spinlocks-with-spinlock_t-for-PREEM.patch new file mode 100644 index 000000000..0ccb2d87c --- /dev/null +++ b/debian/patches-rt/zram-Replace-bit-spinlocks-with-spinlock_t-for-PREEM.patch @@ -0,0 +1,94 @@ +From: Mike Galbraith +Date: Thu, 31 Mar 2016 04:08:28 +0200 +Subject: [PATCH] zram: Replace bit spinlocks with spinlock_t for PREEMPT_RT. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +The bit spinlock disables preemption. The spinlock_t lock becomes a sleeping +lock on PREEMPT_RT and it can not be acquired in this context. In this locked +section, zs_free() acquires a zs_pool::lock, and there is access to +zram::wb_limit_lock. + +Use a spinlock_t on PREEMPT_RT for locking and set/ clear ZRAM_LOCK bit after +the lock has been acquired/ dropped. + +Signed-off-by: Mike Galbraith +Signed-off-by: Sebastian Andrzej Siewior +Link: https://lkml.kernel.org/r/YqIbMuHCPiQk+Ac2@linutronix.de +Link: https://lore.kernel.org/20230323161830.jFbWCosd@linutronix.de +--- + drivers/block/zram/zram_drv.c | 37 +++++++++++++++++++++++++++++++++++++ + drivers/block/zram/zram_drv.h | 3 +++ + 2 files changed, 40 insertions(+) + +--- a/drivers/block/zram/zram_drv.c ++++ b/drivers/block/zram/zram_drv.c +@@ -57,6 +57,41 @@ static void zram_free_page(struct zram * + static int zram_read_page(struct zram *zram, struct page *page, u32 index, + struct bio *parent); + ++#ifdef CONFIG_PREEMPT_RT ++static void zram_meta_init_table_locks(struct zram *zram, size_t num_pages) ++{ ++ size_t index; ++ ++ for (index = 0; index < num_pages; index++) ++ spin_lock_init(&zram->table[index].lock); ++} ++ ++static int zram_slot_trylock(struct zram *zram, u32 index) ++{ ++ int ret; ++ ++ ret = spin_trylock(&zram->table[index].lock); ++ if (ret) ++ __set_bit(ZRAM_LOCK, &zram->table[index].flags); ++ return ret; ++} ++ ++static void zram_slot_lock(struct zram *zram, u32 index) ++{ ++ spin_lock(&zram->table[index].lock); ++ __set_bit(ZRAM_LOCK, &zram->table[index].flags); ++} ++ ++static void zram_slot_unlock(struct zram *zram, u32 index) ++{ ++ __clear_bit(ZRAM_LOCK, &zram->table[index].flags); ++ spin_unlock(&zram->table[index].lock); ++} ++ ++#else ++ ++static void zram_meta_init_table_locks(struct zram *zram, size_t num_pages) { } ++ + static int zram_slot_trylock(struct zram *zram, u32 index) + { + return bit_spin_trylock(ZRAM_LOCK, &zram->table[index].flags); +@@ -71,6 +106,7 @@ static void zram_slot_unlock(struct zram + { + bit_spin_unlock(ZRAM_LOCK, &zram->table[index].flags); + } ++#endif + + static inline bool init_done(struct zram *zram) + { +@@ -1245,6 +1281,7 @@ static bool zram_meta_alloc(struct zram + + if (!huge_class_size) + huge_class_size = zs_huge_class_size(zram->mem_pool); ++ zram_meta_init_table_locks(zram, num_pages); + return true; + } + +--- a/drivers/block/zram/zram_drv.h ++++ b/drivers/block/zram/zram_drv.h +@@ -69,6 +69,9 @@ struct zram_table_entry { + unsigned long element; + }; + unsigned long flags; ++#ifdef CONFIG_PREEMPT_RT ++ spinlock_t lock; ++#endif + #ifdef CONFIG_ZRAM_MEMORY_TRACKING + ktime_t ac_time; + #endif -- cgit v1.2.3