118 lines
4.4 KiB
Diff
118 lines
4.4 KiB
Diff
From 65e31d7b980c1413f19fcb84234387f97b09588f Mon Sep 17 00:00:00 2001
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Thu, 1 Nov 2012 10:14:11 +0100
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Subject: [PATCH 37/62] powerpc: Add support for lazy preemption
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Implement the powerpc pieces for lazy preempt.
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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arch/powerpc/Kconfig | 1 +
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arch/powerpc/include/asm/thread_info.h | 8 ++++++++
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arch/powerpc/kernel/interrupt.c | 8 ++++++--
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3 files changed, 15 insertions(+), 2 deletions(-)
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diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
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index 6050e6e10d32..0eff864d6ec3 100644
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--- a/arch/powerpc/Kconfig
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+++ b/arch/powerpc/Kconfig
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@@ -242,6 +242,7 @@ config PPC
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select HAVE_PERF_EVENTS_NMI if PPC64
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select HAVE_PERF_REGS
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select HAVE_PERF_USER_STACK_DUMP
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+ select HAVE_PREEMPT_LAZY
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select HAVE_REGS_AND_STACK_ACCESS_API
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select HAVE_RELIABLE_STACKTRACE
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select HAVE_RSEQ
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diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h
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index af58f1ed3952..520864de8bb2 100644
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--- a/arch/powerpc/include/asm/thread_info.h
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+++ b/arch/powerpc/include/asm/thread_info.h
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@@ -53,6 +53,8 @@
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struct thread_info {
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int preempt_count; /* 0 => preemptable,
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<0 => BUG */
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+ int preempt_lazy_count; /* 0 => preemptable,
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+ <0 => BUG */
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#ifdef CONFIG_SMP
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unsigned int cpu;
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#endif
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@@ -77,6 +79,7 @@ struct thread_info {
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#define INIT_THREAD_INFO(tsk) \
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{ \
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.preempt_count = INIT_PREEMPT_COUNT, \
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+ .preempt_lazy_count = 0, \
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.flags = 0, \
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}
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@@ -102,6 +105,7 @@ void arch_setup_new_exec(void);
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#define TIF_PATCH_PENDING 6 /* pending live patching update */
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#define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */
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#define TIF_SINGLESTEP 8 /* singlestepping active */
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+#define TIF_NEED_RESCHED_LAZY 9 /* lazy rescheduling necessary */
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#define TIF_SECCOMP 10 /* secure computing */
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#define TIF_RESTOREALL 11 /* Restore all regs (implies NOERROR) */
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#define TIF_NOERROR 12 /* Force successful syscall return */
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@@ -117,6 +121,7 @@ void arch_setup_new_exec(void);
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#define TIF_POLLING_NRFLAG 19 /* true if poll_idle() is polling TIF_NEED_RESCHED */
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#define TIF_32BIT 20 /* 32 bit binary */
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+
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/* as above, but as bit values */
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#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
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#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
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@@ -128,6 +133,7 @@ void arch_setup_new_exec(void);
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#define _TIF_PATCH_PENDING (1<<TIF_PATCH_PENDING)
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#define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT)
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#define _TIF_SINGLESTEP (1<<TIF_SINGLESTEP)
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+#define _TIF_NEED_RESCHED_LAZY (1<<TIF_NEED_RESCHED_LAZY)
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#define _TIF_SECCOMP (1<<TIF_SECCOMP)
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#define _TIF_RESTOREALL (1<<TIF_RESTOREALL)
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#define _TIF_NOERROR (1<<TIF_NOERROR)
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@@ -141,10 +147,12 @@ void arch_setup_new_exec(void);
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_TIF_SYSCALL_EMU)
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#define _TIF_USER_WORK_MASK (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
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+ _TIF_NEED_RESCHED_LAZY | \
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_TIF_NOTIFY_RESUME | _TIF_UPROBE | \
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_TIF_RESTORE_TM | _TIF_PATCH_PENDING | \
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_TIF_NOTIFY_SIGNAL)
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#define _TIF_PERSYSCALL_MASK (_TIF_RESTOREALL|_TIF_NOERROR)
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+#define _TIF_NEED_RESCHED_MASK (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)
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/* Bits in local_flags */
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/* Don't move TLF_NAPPING without adjusting the code in entry_32.S */
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diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c
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index cf770d86c03c..2c454731c250 100644
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--- a/arch/powerpc/kernel/interrupt.c
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+++ b/arch/powerpc/kernel/interrupt.c
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@@ -186,7 +186,7 @@ interrupt_exit_user_prepare_main(unsigned long ret, struct pt_regs *regs)
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ti_flags = read_thread_flags();
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while (unlikely(ti_flags & (_TIF_USER_WORK_MASK & ~_TIF_RESTORE_TM))) {
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local_irq_enable();
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- if (ti_flags & _TIF_NEED_RESCHED) {
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+ if (ti_flags & _TIF_NEED_RESCHED_MASK) {
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schedule();
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} else {
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/*
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@@ -397,11 +397,15 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs)
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/* Returning to a kernel context with local irqs enabled. */
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WARN_ON_ONCE(!(regs->msr & MSR_EE));
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again:
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- if (IS_ENABLED(CONFIG_PREEMPT)) {
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+ if (IS_ENABLED(CONFIG_PREEMPTION)) {
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/* Return to preemptible kernel context */
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if (unlikely(read_thread_flags() & _TIF_NEED_RESCHED)) {
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if (preempt_count() == 0)
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preempt_schedule_irq();
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+ } else if (unlikely(current_thread_info()->flags & _TIF_NEED_RESCHED_LAZY)) {
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+ if ((preempt_count() == 0) &&
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+ (current_thread_info()->preempt_lazy_count == 0))
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+ preempt_schedule_irq();
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}
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}
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--
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2.43.0
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