diff options
Diffstat (limited to 'debian/patches-rt/0036-arm-Add-support-for-lazy-preemption.patch')
| -rw-r--r-- | debian/patches-rt/0036-arm-Add-support-for-lazy-preemption.patch | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/debian/patches-rt/0036-arm-Add-support-for-lazy-preemption.patch b/debian/patches-rt/0036-arm-Add-support-for-lazy-preemption.patch new file mode 100644 index 000000000..8f76d13b0 --- /dev/null +++ b/debian/patches-rt/0036-arm-Add-support-for-lazy-preemption.patch @@ -0,0 +1,137 @@ +From f242fbbb3f85d6b9c8c8fc06ddbc83b9ca5a0511 Mon Sep 17 00:00:00 2001 +From: Thomas Gleixner <tglx@linutronix.de> +Date: Wed, 31 Oct 2012 12:04:11 +0100 +Subject: [PATCH 36/62] arm: Add support for lazy preemption +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.1/older/patches-6.1.69-rt21.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 | 6 +++++- + arch/arm/kernel/asm-offsets.c | 1 + + arch/arm/kernel/entry-armv.S | 19 ++++++++++++++++--- + arch/arm/kernel/signal.c | 3 ++- + 5 files changed, 25 insertions(+), 5 deletions(-) + +diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig +index 6d5afe2e6ba3..717e596dc13b 100644 +--- a/arch/arm/Kconfig ++++ b/arch/arm/Kconfig +@@ -115,6 +115,7 @@ config ARM + select HAVE_PERF_EVENTS + select HAVE_PERF_REGS + select HAVE_PERF_USER_STACK_DUMP ++ select HAVE_PREEMPT_LAZY + select MMU_GATHER_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 7f092cb55a41..ffcbf8ebed4b 100644 +--- a/arch/arm/include/asm/thread_info.h ++++ b/arch/arm/include/asm/thread_info.h +@@ -62,6 +62,7 @@ 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 */ + __u32 cpu; /* cpu */ + __u32 cpu_domain; /* cpu domain */ + struct cpu_context_save cpu_context; /* cpu context */ +@@ -129,6 +130,7 @@ extern int vfp_restore_user_hwstate(struct user_vfp *, + #define TIF_NOTIFY_RESUME 2 /* callback before returning to user */ + #define TIF_UPROBE 3 /* breakpointed or singlestepping */ + #define TIF_NOTIFY_SIGNAL 4 /* signal notifications exist */ ++#define TIF_NEED_RESCHED_LAZY 5 + + #define TIF_USING_IWMMXT 17 + #define TIF_MEMDIE 18 /* is terminating due to OOM killer */ +@@ -148,6 +150,7 @@ extern int vfp_restore_user_hwstate(struct user_vfp *, + #define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT) + #define _TIF_SECCOMP (1 << TIF_SECCOMP) + #define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL) ++#define _TIF_NEED_RESCHED_LAZY (1 << TIF_NEED_RESCHED_LAZY) + #define _TIF_USING_IWMMXT (1 << TIF_USING_IWMMXT) + + /* Checks for any syscall work in entry-common.S */ +@@ -157,7 +160,8 @@ 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 | \ ++#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY | \ ++ _TIF_SIGPENDING | \ + _TIF_NOTIFY_RESUME | _TIF_UPROBE | \ + _TIF_NOTIFY_SIGNAL) + +diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c +index 2c8d76fd7c66..c3bdec7d2df9 100644 +--- a/arch/arm/kernel/asm-offsets.c ++++ b/arch/arm/kernel/asm-offsets.c +@@ -43,6 +43,7 @@ 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_CPU, offsetof(struct thread_info, cpu)); + DEFINE(TI_CPU_DOMAIN, offsetof(struct thread_info, cpu_domain)); + DEFINE(TI_CPU_SAVE, offsetof(struct thread_info, cpu_context)); +diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S +index c39303e5c234..cfb4660e9fea 100644 +--- a/arch/arm/kernel/entry-armv.S ++++ b/arch/arm/kernel/entry-armv.S +@@ -222,11 +222,18 @@ ENDPROC(__dabt_svc) + + #ifdef CONFIG_PREEMPTION + 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 +@@ -241,8 +248,14 @@ 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/signal.c b/arch/arm/kernel/signal.c +index e07f359254c3..b50a3248e79f 100644 +--- a/arch/arm/kernel/signal.c ++++ b/arch/arm/kernel/signal.c +@@ -607,7 +607,8 @@ 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))) +-- +2.43.0 + |