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Diffstat (limited to '')
| -rw-r--r-- | debian/patches-rt/0242-arm-Add-support-for-lazy-preemption.patch | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/debian/patches-rt/0242-arm-Add-support-for-lazy-preemption.patch b/debian/patches-rt/0242-arm-Add-support-for-lazy-preemption.patch new file mode 100644 index 000000000..af7fd9bc3 --- /dev/null +++ b/debian/patches-rt/0242-arm-Add-support-for-lazy-preemption.patch @@ -0,0 +1,168 @@ +From 3845cb2e5f05561da9e363932c9373f45b5fa6a4 Mon Sep 17 00:00:00 2001 +From: Thomas Gleixner <tglx@linutronix.de> +Date: Wed, 31 Oct 2012 12:04:11 +0100 +Subject: [PATCH 242/347] arm: Add support for lazy preemption +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz + +Implement the arm pieces for lazy preempt. + +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +--- + arch/arm/Kconfig | 1 + + arch/arm/include/asm/thread_info.h | 8 ++++++-- + arch/arm/kernel/asm-offsets.c | 1 + + arch/arm/kernel/entry-armv.S | 19 ++++++++++++++++--- + arch/arm/kernel/entry-common.S | 9 +++++++-- + arch/arm/kernel/signal.c | 3 ++- + 6 files changed, 33 insertions(+), 8 deletions(-) + +diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig +index ec99422059e3..2607cae04885 100644 +--- a/arch/arm/Kconfig ++++ b/arch/arm/Kconfig +@@ -91,6 +91,7 @@ config ARM + select HAVE_PERF_EVENTS + select HAVE_PERF_REGS + select HAVE_PERF_USER_STACK_DUMP ++ select HAVE_PREEMPT_LAZY + select HAVE_RCU_TABLE_FREE if (SMP && ARM_LPAE) + select HAVE_REGS_AND_STACK_ACCESS_API + select HAVE_RSEQ +diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h +index 8f55dc520a3e..4f834bfca470 100644 +--- a/arch/arm/include/asm/thread_info.h ++++ b/arch/arm/include/asm/thread_info.h +@@ -49,6 +49,7 @@ struct cpu_context_save { + struct thread_info { + unsigned long flags; /* low level flags */ + int preempt_count; /* 0 => preemptable, <0 => bug */ ++ int preempt_lazy_count; /* 0 => preemptable, <0 => bug */ + mm_segment_t addr_limit; /* address limit */ + struct task_struct *task; /* main task structure */ + __u32 cpu; /* cpu */ +@@ -139,7 +140,8 @@ extern int vfp_restore_user_hwstate(struct user_vfp *, + #define TIF_SYSCALL_TRACE 4 /* syscall trace active */ + #define TIF_SYSCALL_AUDIT 5 /* syscall auditing active */ + #define TIF_SYSCALL_TRACEPOINT 6 /* syscall tracepoint instrumentation */ +-#define TIF_SECCOMP 7 /* seccomp syscall filtering active */ ++#define TIF_SECCOMP 8 /* seccomp syscall filtering active */ ++#define TIF_NEED_RESCHED_LAZY 7 + + #define TIF_NOHZ 12 /* in adaptive nohz mode */ + #define TIF_USING_IWMMXT 17 +@@ -149,6 +151,7 @@ extern int vfp_restore_user_hwstate(struct user_vfp *, + #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) + #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) + #define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME) ++#define _TIF_NEED_RESCHED_LAZY (1 << TIF_NEED_RESCHED_LAZY) + #define _TIF_UPROBE (1 << TIF_UPROBE) + #define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE) + #define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT) +@@ -164,7 +167,8 @@ extern int vfp_restore_user_hwstate(struct user_vfp *, + * Change these and you break ASM code in entry-common.S + */ + #define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \ +- _TIF_NOTIFY_RESUME | _TIF_UPROBE) ++ _TIF_NOTIFY_RESUME | _TIF_UPROBE | \ ++ _TIF_NEED_RESCHED_LAZY) + + #endif /* __KERNEL__ */ + #endif /* __ASM_ARM_THREAD_INFO_H */ +diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c +index 40afe953a0e2..d634d6f36140 100644 +--- a/arch/arm/kernel/asm-offsets.c ++++ b/arch/arm/kernel/asm-offsets.c +@@ -58,6 +58,7 @@ int main(void) + BLANK(); + DEFINE(TI_FLAGS, offsetof(struct thread_info, flags)); + DEFINE(TI_PREEMPT, offsetof(struct thread_info, preempt_count)); ++ DEFINE(TI_PREEMPT_LAZY, offsetof(struct thread_info, preempt_lazy_count)); + DEFINE(TI_ADDR_LIMIT, offsetof(struct thread_info, addr_limit)); + DEFINE(TI_TASK, offsetof(struct thread_info, task)); + DEFINE(TI_CPU, offsetof(struct thread_info, cpu)); +diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S +index d779cd1a3b0c..dc7ae3d8e62f 100644 +--- a/arch/arm/kernel/entry-armv.S ++++ b/arch/arm/kernel/entry-armv.S +@@ -209,11 +209,18 @@ ENDPROC(__dabt_svc) + + #ifdef CONFIG_PREEMPT + ldr r8, [tsk, #TI_PREEMPT] @ get preempt count +- ldr r0, [tsk, #TI_FLAGS] @ get flags + teq r8, #0 @ if preempt count != 0 ++ bne 1f @ return from exeption ++ ldr r0, [tsk, #TI_FLAGS] @ get flags ++ tst r0, #_TIF_NEED_RESCHED @ if NEED_RESCHED is set ++ blne svc_preempt @ preempt! ++ ++ ldr r8, [tsk, #TI_PREEMPT_LAZY] @ get preempt lazy count ++ teq r8, #0 @ if preempt lazy count != 0 + movne r0, #0 @ force flags to 0 +- tst r0, #_TIF_NEED_RESCHED ++ tst r0, #_TIF_NEED_RESCHED_LAZY + blne svc_preempt ++1: + #endif + + svc_exit r5, irq = 1 @ return from exception +@@ -228,8 +235,14 @@ ENDPROC(__irq_svc) + 1: bl preempt_schedule_irq @ irq en/disable is done inside + ldr r0, [tsk, #TI_FLAGS] @ get new tasks TI_FLAGS + tst r0, #_TIF_NEED_RESCHED ++ bne 1b ++ tst r0, #_TIF_NEED_RESCHED_LAZY + reteq r8 @ go again +- b 1b ++ ldr r0, [tsk, #TI_PREEMPT_LAZY] @ get preempt lazy count ++ teq r0, #0 @ if preempt lazy count != 0 ++ beq 1b ++ ret r8 @ go again ++ + #endif + + __und_fault: +diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S +index e27fc2df5231..bc326519f648 100644 +--- a/arch/arm/kernel/entry-common.S ++++ b/arch/arm/kernel/entry-common.S +@@ -56,7 +56,9 @@ saved_pc .req lr + cmp r2, #TASK_SIZE + blne addr_limit_check_failed + ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing +- tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK ++ tst r1, #((_TIF_SYSCALL_WORK | _TIF_WORK_MASK) & ~_TIF_SECCOMP) ++ bne fast_work_pending ++ tst r1, #_TIF_SECCOMP + bne fast_work_pending + + +@@ -93,8 +95,11 @@ ENDPROC(ret_fast_syscall) + cmp r2, #TASK_SIZE + blne addr_limit_check_failed + ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing +- tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK ++ tst r1, #((_TIF_SYSCALL_WORK | _TIF_WORK_MASK) & ~_TIF_SECCOMP) ++ bne do_slower_path ++ tst r1, #_TIF_SECCOMP + beq no_work_pending ++do_slower_path: + UNWIND(.fnend ) + ENDPROC(ret_fast_syscall) + +diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c +index 1c01358b9b6d..263b0321dc50 100644 +--- a/arch/arm/kernel/signal.c ++++ b/arch/arm/kernel/signal.c +@@ -652,7 +652,8 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall) + */ + trace_hardirqs_off(); + do { +- if (likely(thread_flags & _TIF_NEED_RESCHED)) { ++ if (likely(thread_flags & (_TIF_NEED_RESCHED | ++ _TIF_NEED_RESCHED_LAZY))) { + schedule(); + } else { + if (unlikely(!user_mode(regs))) +-- +2.36.1 + |