From 89b3098703bd2aa3237ef10a704e6a5838e6ea69 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 12 Jan 2023 20:43:35 +0100 Subject: [PATCH] arch/idle: Change arch_cpu_idle() behavior: always exit with IRQs disabled Current arch_cpu_idle() is called with IRQs disabled, but will return with IRQs enabled. However, the very first thing the generic code does after calling arch_cpu_idle() is raw_local_irq_disable(). This means that architectures that can idle with IRQs disabled end up doing a pointless 'enable-disable' dance. Therefore, push this IRQ disabling into the idle function, meaning that those architectures can avoid the pointless IRQ state flipping. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Tested-by: Tony Lindgren Tested-by: Ulf Hansson Reviewed-by: Gautham R. Shenoy Acked-by: Mark Rutland [arm64] Acked-by: Rafael J. Wysocki Acked-by: Guo Ren Acked-by: Frederic Weisbecker Link: https://lore.kernel.org/r/20230112195540.618076436@infradead.org --- arch/alpha/kernel/process.c | 1 - arch/arc/kernel/process.c | 3 +++ arch/arm/kernel/process.c | 1 - arch/arm/mach-gemini/board-dt.c | 3 ++- arch/arm64/kernel/idle.c | 1 - arch/csky/kernel/process.c | 1 - arch/csky/kernel/smp.c | 2 +- arch/hexagon/kernel/process.c | 1 - arch/ia64/kernel/process.c | 1 + arch/loongarch/kernel/idle.c | 1 + arch/microblaze/kernel/process.c | 1 - arch/mips/kernel/idle.c | 8 +++----- arch/nios2/kernel/process.c | 1 - arch/openrisc/kernel/process.c | 1 + arch/parisc/kernel/process.c | 2 -- arch/powerpc/kernel/idle.c | 5 ++--- arch/riscv/kernel/process.c | 1 - arch/s390/kernel/idle.c | 1 - arch/sh/kernel/idle.c | 1 + arch/sparc/kernel/leon_pmc.c | 4 ++++ arch/sparc/kernel/process_32.c | 1 - arch/sparc/kernel/process_64.c | 3 ++- arch/um/kernel/process.c | 1 - arch/x86/coco/tdx/tdx.c | 3 +++ arch/x86/kernel/process.c | 15 ++++----------- arch/xtensa/kernel/process.c | 1 + kernel/sched/idle.c | 2 -- 27 files changed, 29 insertions(+), 37 deletions(-) diff --git a/arch/alpha/kernel/process.c b/arch/alpha/kernel/process.c index 65fdae9..ce20c31 100644 --- a/arch/alpha/kernel/process.c +++ b/arch/alpha/kernel/process.c @@ -57,7 +57,6 @@ EXPORT_SYMBOL(pm_power_off); void arch_cpu_idle(void) { wtint(0); - raw_local_irq_enable(); } void arch_cpu_idle_dead(void) diff --git a/arch/arc/kernel/process.c b/arch/arc/kernel/process.c index 3369f07..980b71d 100644 --- a/arch/arc/kernel/process.c +++ b/arch/arc/kernel/process.c @@ -114,6 +114,8 @@ void arch_cpu_idle(void) "sleep %0 \n" : :"I"(arg)); /* can't be "r" has to be embedded const */ + + raw_local_irq_disable(); } #else /* ARC700 */ @@ -122,6 +124,7 @@ void arch_cpu_idle(void) { /* sleep, but enable both set E1/E2 (levels of interrupts) before committing */ __asm__ __volatile__("sleep 0x3 \n"); + raw_local_irq_disable(); } #endif diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index f811733..c81e7be 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -78,7 +78,6 @@ void arch_cpu_idle(void) arm_pm_idle(); else cpu_do_idle(); - raw_local_irq_enable(); } void arch_cpu_idle_prepare(void) diff --git a/arch/arm/mach-gemini/board-dt.c b/arch/arm/mach-gemini/board-dt.c index de0afcc..fbafe74 100644 --- a/arch/arm/mach-gemini/board-dt.c +++ b/arch/arm/mach-gemini/board-dt.c @@ -42,8 +42,9 @@ static void gemini_idle(void) */ /* FIXME: Enabling interrupts here is racy! */ - local_irq_enable(); + raw_local_irq_enable(); cpu_do_idle(); + raw_local_irq_disable(); } static void __init gemini_init_machine(void) diff --git a/arch/arm64/kernel/idle.c b/arch/arm64/kernel/idle.c index a2cfbace..c112575 100644 --- a/arch/arm64/kernel/idle.c +++ b/arch/arm64/kernel/idle.c @@ -42,5 +42,4 @@ void noinstr arch_cpu_idle(void) * tricks */ cpu_do_idle(); - raw_local_irq_enable(); } diff --git a/arch/csky/kernel/process.c b/arch/csky/kernel/process.c index 2b0ed51..0c6e4b1 100644 --- a/arch/csky/kernel/process.c +++ b/arch/csky/kernel/process.c @@ -100,6 +100,5 @@ void arch_cpu_idle(void) #ifdef CONFIG_CPU_PM_STOP asm volatile("stop\n"); #endif - raw_local_irq_enable(); } #endif diff --git a/arch/csky/kernel/smp.c b/arch/csky/kernel/smp.c index 4b605aa..b45d107 100644 --- a/arch/csky/kernel/smp.c +++ b/arch/csky/kernel/smp.c @@ -309,7 +309,7 @@ void arch_cpu_idle_dead(void) while (!secondary_stack) arch_cpu_idle(); - local_irq_disable(); + raw_local_irq_disable(); asm volatile( "mov sp, %0\n" diff --git a/arch/hexagon/kernel/process.c b/arch/hexagon/kernel/process.c index e15eeae..dd7f74e 100644 --- a/arch/hexagon/kernel/process.c +++ b/arch/hexagon/kernel/process.c @@ -44,7 +44,6 @@ void arch_cpu_idle(void) { __vmwait(); /* interrupts wake us up, but irqs are still disabled */ - raw_local_irq_enable(); } /* diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c index 416305e..f6195a0 100644 --- a/arch/ia64/kernel/process.c +++ b/arch/ia64/kernel/process.c @@ -242,6 +242,7 @@ void arch_cpu_idle(void) (*mark_idle)(1); raw_safe_halt(); + raw_local_irq_disable(); if (mark_idle) (*mark_idle)(0); diff --git a/arch/loongarch/kernel/idle.c b/arch/loongarch/kernel/idle.c index 1a65d05..0b5dd2f 100644 --- a/arch/loongarch/kernel/idle.c +++ b/arch/loongarch/kernel/idle.c @@ -13,4 +13,5 @@ void __cpuidle arch_cpu_idle(void) { raw_local_irq_enable(); __arch_cpu_idle(); /* idle instruction needs irq enabled */ + raw_local_irq_disable(); } diff --git a/arch/microblaze/kernel/process.c b/arch/microblaze/kernel/process.c index 1f802aa..56342e1 100644 --- a/arch/microblaze/kernel/process.c +++ b/arch/microblaze/kernel/process.c @@ -140,5 +140,4 @@ int elf_core_copy_task_fpregs(struct task_struct *t, elf_fpregset_t *fpu) void arch_cpu_idle(void) { - raw_local_irq_enable(); } diff --git a/arch/mips/kernel/idle.c b/arch/mips/kernel/idle.c index 53adcc1..3e7ccdd 100644 --- a/arch/mips/kernel/idle.c +++ b/arch/mips/kernel/idle.c @@ -33,13 +33,13 @@ static void __cpuidle r3081_wait(void) { unsigned long cfg = read_c0_conf(); write_c0_conf(cfg | R30XX_CONF_HALT); - raw_local_irq_enable(); } void __cpuidle r4k_wait(void) { raw_local_irq_enable(); __r4k_wait(); + raw_local_irq_disable(); } /* @@ -57,7 +57,6 @@ void __cpuidle r4k_wait_irqoff(void) " .set arch=r4000 \n" " wait \n" " .set pop \n"); - raw_local_irq_enable(); } /* @@ -77,7 +76,6 @@ static void __cpuidle rm7k_wait_irqoff(void) " wait \n" " mtc0 $1, $12 # stalls until W stage \n" " .set pop \n"); - raw_local_irq_enable(); } /* @@ -103,6 +101,8 @@ static void __cpuidle au1k_wait(void) " nop \n" " .set pop \n" : : "r" (au1k_wait), "r" (c0status)); + + raw_local_irq_disable(); } static int __initdata nowait; @@ -245,8 +245,6 @@ void arch_cpu_idle(void) { if (cpu_wait) cpu_wait(); - else - raw_local_irq_enable(); } #ifdef CONFIG_CPU_IDLE diff --git a/arch/nios2/kernel/process.c b/arch/nios2/kernel/process.c index 29593b9..f840213 100644 --- a/arch/nios2/kernel/process.c +++ b/arch/nios2/kernel/process.c @@ -33,7 +33,6 @@ EXPORT_SYMBOL(pm_power_off); void arch_cpu_idle(void) { - raw_local_irq_enable(); } /* diff --git a/arch/openrisc/kernel/process.c b/arch/openrisc/kernel/process.c index f94b5ec..dfa558f 100644 --- a/arch/openrisc/kernel/process.c +++ b/arch/openrisc/kernel/process.c @@ -102,6 +102,7 @@ void arch_cpu_idle(void) raw_local_irq_enable(); if (mfspr(SPR_UPR) & SPR_UPR_PMP) mtspr(SPR_PMR, mfspr(SPR_PMR) | SPR_PMR_DME); + raw_local_irq_disable(); } void (*pm_power_off)(void) = NULL; diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c index c4f8374..c064719 100644 --- a/arch/parisc/kernel/process.c +++ b/arch/parisc/kernel/process.c @@ -183,8 +183,6 @@ void arch_cpu_idle_dead(void) void __cpuidle arch_cpu_idle(void) { - raw_local_irq_enable(); - /* nop on real hardware, qemu will idle sleep. */ asm volatile("or %%r10,%%r10,%%r10\n":::); } diff --git a/arch/powerpc/kernel/idle.c b/arch/powerpc/kernel/idle.c index 77cd4c5..b9a725a 100644 --- a/arch/powerpc/kernel/idle.c +++ b/arch/powerpc/kernel/idle.c @@ -51,10 +51,9 @@ void arch_cpu_idle(void) * Some power_save functions return with * interrupts enabled, some don't. */ - if (irqs_disabled()) - raw_local_irq_enable(); + if (!irqs_disabled()) + raw_local_irq_disable(); } else { - raw_local_irq_enable(); /* * Go into low thread priority and possibly * low power mode. diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c index 8955f24..774ffde 100644 --- a/arch/riscv/kernel/process.c +++ b/arch/riscv/kernel/process.c @@ -39,7 +39,6 @@ extern asmlinkage void ret_from_kernel_thread(void); void arch_cpu_idle(void) { cpu_do_idle(); - raw_local_irq_enable(); } void __show_regs(struct pt_regs *regs) diff --git a/arch/s390/kernel/idle.c b/arch/s390/kernel/idle.c index a6bbcea..b04fb41 100644 --- a/arch/s390/kernel/idle.c +++ b/arch/s390/kernel/idle.c @@ -66,7 +66,6 @@ void arch_cpu_idle(void) idle->idle_count++; account_idle_time(cputime_to_nsecs(idle_time)); raw_write_seqcount_end(&idle->seqcount); - raw_local_irq_enable(); } static ssize_t show_idle_count(struct device *dev, diff --git a/arch/sh/kernel/idle.c b/arch/sh/kernel/idle.c index f598149..3418c40 100644 --- a/arch/sh/kernel/idle.c +++ b/arch/sh/kernel/idle.c @@ -25,6 +25,7 @@ void default_idle(void) raw_local_irq_enable(); /* Isn't this racy ? */ cpu_sleep(); + raw_local_irq_disable(); clear_bl_bit(); } diff --git a/arch/sparc/kernel/leon_pmc.c b/arch/sparc/kernel/leon_pmc.c index 396f46b..6c00cba 100644 --- a/arch/sparc/kernel/leon_pmc.c +++ b/arch/sparc/kernel/leon_pmc.c @@ -57,6 +57,8 @@ static void pmc_leon_idle_fixup(void) "lda [%0] %1, %%g0\n" : : "r"(address), "i"(ASI_LEON_BYPASS)); + + raw_local_irq_disable(); } /* @@ -70,6 +72,8 @@ static void pmc_leon_idle(void) /* For systems without power-down, this will be no-op */ __asm__ __volatile__ ("wr %g0, %asr19\n\t"); + + raw_local_irq_disable(); } /* Install LEON Power Down function */ diff --git a/arch/sparc/kernel/process_32.c b/arch/sparc/kernel/process_32.c index 33b0215..9c7c662 100644 --- a/arch/sparc/kernel/process_32.c +++ b/arch/sparc/kernel/process_32.c @@ -71,7 +71,6 @@ void arch_cpu_idle(void) { if (sparc_idle) (*sparc_idle)(); - raw_local_irq_enable(); } /* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */ diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c index 6335b69..91c2b81 100644 --- a/arch/sparc/kernel/process_64.c +++ b/arch/sparc/kernel/process_64.c @@ -59,7 +59,6 @@ void arch_cpu_idle(void) { if (tlb_type != hypervisor) { touch_nmi_watchdog(); - raw_local_irq_enable(); } else { unsigned long pstate; @@ -90,6 +89,8 @@ void arch_cpu_idle(void) "wrpr %0, %%g0, %%pstate" : "=&r" (pstate) : "i" (PSTATE_IE)); + + raw_local_irq_disable(); } } diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c index 47830ad..106b7da 100644 --- a/arch/um/kernel/process.c +++ b/arch/um/kernel/process.c @@ -218,7 +218,6 @@ void arch_cpu_idle(void) { cpu_tasks[current_thread_info()->cpu].pid = os_getpid(); um_idle_sleep(); - raw_local_irq_enable(); } int __cant_sleep(void) { diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c index cfd4c95..f4a59c3 100644 --- a/arch/x86/coco/tdx/tdx.c +++ b/arch/x86/coco/tdx/tdx.c @@ -274,6 +274,9 @@ void __cpuidle tdx_safe_halt(void) */ if (__halt(irq_disabled, do_sti)) WARN_ONCE(1, "HLT instruction emulation failed\n"); + + /* XXX I can't make sense of what @do_sti actually does */ + raw_local_irq_disable(); } static int read_msr(struct pt_regs *regs, struct ve_info *ve) diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 8481fbe..e57cd31 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -701,6 +701,7 @@ EXPORT_SYMBOL(boot_option_idle_override); void __cpuidle default_idle(void) { raw_safe_halt(); + raw_local_irq_disable(); } #if defined(CONFIG_APM_MODULE) || defined(CONFIG_HALTPOLL_CPUIDLE_MODULE) EXPORT_SYMBOL(default_idle); @@ -806,13 +807,7 @@ static void amd_e400_idle(void) default_idle(); - /* - * The switch back from broadcast mode needs to be called with - * interrupts disabled. - */ - raw_local_irq_disable(); tick_broadcast_exit(); - raw_local_irq_enable(); } /* @@ -870,12 +865,10 @@ static __cpuidle void mwait_idle(void) } __monitor((void *)¤t_thread_info()->flags, 0, 0); - if (!need_resched()) + if (!need_resched()) { __sti_mwait(0, 0); - else - raw_local_irq_enable(); - } else { - raw_local_irq_enable(); + raw_local_irq_disable(); + } } __current_clr_polling(); } diff --git a/arch/xtensa/kernel/process.c b/arch/xtensa/kernel/process.c index 68e0e2f..a815577 100644 --- a/arch/xtensa/kernel/process.c +++ b/arch/xtensa/kernel/process.c @@ -183,6 +183,7 @@ void coprocessor_flush_release_all(struct thread_info *ti) void arch_cpu_idle(void) { platform_idle(); + raw_local_irq_disable(); } /* diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index e924602..e9ef66b 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -79,7 +79,6 @@ void __weak arch_cpu_idle_dead(void) { } void __weak arch_cpu_idle(void) { cpu_idle_force_poll = 1; - raw_local_irq_enable(); } /** @@ -96,7 +95,6 @@ void __cpuidle default_idle_call(void) ct_cpuidle_enter(); arch_cpu_idle(); - raw_local_irq_disable(); ct_cpuidle_exit(); start_critical_timings(); -- 2.7.4