| Subject: arm-preempt-lazy-support.patch |
| From: Thomas Gleixner <tglx@linutronix.de> |
| Date: Wed, 31 Oct 2012 12:04:11 +0100 |
| |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| --- |
| arch/arm/Kconfig | 1 + |
| arch/arm/include/asm/thread_info.h | 3 +++ |
| arch/arm/kernel/asm-offsets.c | 1 + |
| arch/arm/kernel/entry-armv.S | 13 +++++++++++-- |
| arch/arm/kernel/signal.c | 3 ++- |
| 5 files changed, 18 insertions(+), 3 deletions(-) |
| |
| Index: linux-stable/arch/arm/Kconfig |
| =================================================================== |
| --- linux-stable.orig/arch/arm/Kconfig |
| +++ linux-stable/arch/arm/Kconfig |
| @@ -50,6 +50,7 @@ config ARM |
| select GENERIC_STRNCPY_FROM_USER |
| select GENERIC_STRNLEN_USER |
| select DCACHE_WORD_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && !CPU_BIG_ENDIAN |
| + select HAVE_PREEMPT_LAZY |
| help |
| The ARM series is a line of low-power-consumption RISC chip designs |
| licensed by ARM Ltd and targeted at embedded applications and |
| Index: linux-stable/arch/arm/include/asm/thread_info.h |
| =================================================================== |
| --- linux-stable.orig/arch/arm/include/asm/thread_info.h |
| +++ linux-stable/arch/arm/include/asm/thread_info.h |
| @@ -50,6 +50,7 @@ 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 */ |
| struct exec_domain *exec_domain; /* execution domain */ |
| @@ -146,6 +147,7 @@ extern int vfp_restore_user_hwstate(stru |
| #define TIF_SIGPENDING 0 |
| #define TIF_NEED_RESCHED 1 |
| #define TIF_NOTIFY_RESUME 2 /* callback before returning to user */ |
| +#define TIF_NEED_RESCHED_LAZY 3 |
| #define TIF_SYSCALL_TRACE 8 |
| #define TIF_SYSCALL_AUDIT 9 |
| #define TIF_POLLING_NRFLAG 16 |
| @@ -158,6 +160,7 @@ extern int vfp_restore_user_hwstate(stru |
| #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_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE) |
| #define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT) |
| #define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG) |
| Index: linux-stable/arch/arm/kernel/asm-offsets.c |
| =================================================================== |
| --- linux-stable.orig/arch/arm/kernel/asm-offsets.c |
| +++ linux-stable/arch/arm/kernel/asm-offsets.c |
| @@ -50,6 +50,7 @@ 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_EXEC_DOMAIN, offsetof(struct thread_info, exec_domain)); |
| Index: linux-stable/arch/arm/kernel/entry-armv.S |
| =================================================================== |
| --- linux-stable.orig/arch/arm/kernel/entry-armv.S |
| +++ linux-stable/arch/arm/kernel/entry-armv.S |
| @@ -216,11 +216,18 @@ __irq_svc: |
| #ifdef CONFIG_PREEMPT |
| get_thread_info tsk |
| 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 |
| |
| #ifdef CONFIG_TRACE_IRQFLAGS |
| @@ -240,6 +247,8 @@ svc_preempt: |
| 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 |
| moveq pc, r8 @ go again |
| b 1b |
| #endif |
| Index: linux-stable/arch/arm/kernel/signal.c |
| =================================================================== |
| --- linux-stable.orig/arch/arm/kernel/signal.c |
| +++ linux-stable/arch/arm/kernel/signal.c |
| @@ -639,7 +639,8 @@ asmlinkage int |
| do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall) |
| { |
| 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))) |