106 lines
4.3 KiB
Diff
106 lines
4.3 KiB
Diff
Subject: arm-preempt-lazy-support.patch
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Wed, 31 Oct 2012 12:04:11 +0100
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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arch/arm/Kconfig | 1 +
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arch/arm/include/asm/thread_info.h | 3 +++
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arch/arm/kernel/asm-offsets.c | 1 +
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arch/arm/kernel/entry-armv.S | 8 ++++++++
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arch/arm/kernel/signal.c | 3 ++-
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5 files changed, 15 insertions(+), 1 deletion(-)
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Index: linux-stable/arch/arm/Kconfig
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===================================================================
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--- linux-stable.orig/arch/arm/Kconfig
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+++ linux-stable/arch/arm/Kconfig
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@@ -50,6 +50,7 @@ config ARM
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select GENERIC_STRNCPY_FROM_USER
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select GENERIC_STRNLEN_USER
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select DCACHE_WORD_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && !CPU_BIG_ENDIAN
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+ select HAVE_PREEMPT_LAZY
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help
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The ARM series is a line of low-power-consumption RISC chip designs
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licensed by ARM Ltd and targeted at embedded applications and
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Index: linux-stable/arch/arm/include/asm/thread_info.h
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===================================================================
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--- linux-stable.orig/arch/arm/include/asm/thread_info.h
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+++ linux-stable/arch/arm/include/asm/thread_info.h
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@@ -50,6 +50,7 @@ struct cpu_context_save {
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struct thread_info {
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unsigned long flags; /* low level flags */
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int preempt_count; /* 0 => preemptable, <0 => bug */
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+ int preempt_lazy_count; /* 0 => preemptable, <0 => bug */
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mm_segment_t addr_limit; /* address limit */
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struct task_struct *task; /* main task structure */
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struct exec_domain *exec_domain; /* execution domain */
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@@ -146,6 +147,7 @@ extern int vfp_restore_user_hwstate(stru
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#define TIF_SIGPENDING 0
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#define TIF_NEED_RESCHED 1
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#define TIF_NOTIFY_RESUME 2 /* callback before returning to user */
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+#define TIF_NEED_RESCHED_LAZY 3
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#define TIF_SYSCALL_TRACE 8
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#define TIF_SYSCALL_AUDIT 9
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#define TIF_POLLING_NRFLAG 16
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@@ -158,6 +160,7 @@ extern int vfp_restore_user_hwstate(stru
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#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
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#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
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#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
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+#define _TIF_NEED_RESCHED_LAZY (1 << TIF_NEED_RESCHED_LAZY)
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#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
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#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
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#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
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Index: linux-stable/arch/arm/kernel/asm-offsets.c
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===================================================================
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--- linux-stable.orig/arch/arm/kernel/asm-offsets.c
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+++ linux-stable/arch/arm/kernel/asm-offsets.c
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@@ -50,6 +50,7 @@ int main(void)
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BLANK();
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DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
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DEFINE(TI_PREEMPT, offsetof(struct thread_info, preempt_count));
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+ DEFINE(TI_PREEMPT_LAZY, offsetof(struct thread_info, preempt_lazy_count));
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DEFINE(TI_ADDR_LIMIT, offsetof(struct thread_info, addr_limit));
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DEFINE(TI_TASK, offsetof(struct thread_info, task));
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DEFINE(TI_EXEC_DOMAIN, offsetof(struct thread_info, exec_domain));
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Index: linux-stable/arch/arm/kernel/entry-armv.S
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===================================================================
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--- linux-stable.orig/arch/arm/kernel/entry-armv.S
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+++ linux-stable/arch/arm/kernel/entry-armv.S
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@@ -221,6 +221,12 @@ __irq_svc:
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movne r0, #0 @ force flags to 0
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tst r0, #_TIF_NEED_RESCHED
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blne svc_preempt
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+ ldr r8, [tsk, #TI_PREEMPT_LAZY] @ get preempt lazy count
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+ ldr r0, [tsk, #TI_FLAGS] @ get flags
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+ teq r8, #0 @ if preempt lazy count != 0
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+ movne r0, #0 @ force flags to 0
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+ tst r0, #_TIF_NEED_RESCHED_LAZY
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+ blne svc_preempt
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#endif
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#ifdef CONFIG_TRACE_IRQFLAGS
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@@ -240,6 +246,8 @@ svc_preempt:
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1: bl preempt_schedule_irq @ irq en/disable is done inside
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ldr r0, [tsk, #TI_FLAGS] @ get new tasks TI_FLAGS
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tst r0, #_TIF_NEED_RESCHED
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+ bne 1b
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+ tst r0, #_TIF_NEED_RESCHED_LAZY
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moveq pc, r8 @ go again
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b 1b
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#endif
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Index: linux-stable/arch/arm/kernel/signal.c
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===================================================================
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--- linux-stable.orig/arch/arm/kernel/signal.c
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+++ linux-stable/arch/arm/kernel/signal.c
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@@ -639,7 +639,8 @@ asmlinkage int
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do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
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{
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do {
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- if (likely(thread_flags & _TIF_NEED_RESCHED)) {
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+ if (likely(thread_flags & (_TIF_NEED_RESCHED |
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+ _TIF_NEED_RESCHED_LAZY))) {
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schedule();
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} else {
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if (unlikely(!user_mode(regs)))
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