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Message-ID: <20220919101521.743503410@infradead.org>
Date: Mon, 19 Sep 2022 12:00:00 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: peterz@...radead.org
Cc: richard.henderson@...aro.org, ink@...assic.park.msu.ru,
mattst88@...il.com, vgupta@...nel.org, linux@...linux.org.uk,
ulli.kroll@...glemail.com, linus.walleij@...aro.org,
shawnguo@...nel.org, Sascha Hauer <s.hauer@...gutronix.de>,
kernel@...gutronix.de, festevam@...il.com, linux-imx@....com,
tony@...mide.com, khilman@...nel.org, catalin.marinas@....com,
will@...nel.org, guoren@...nel.org, bcain@...cinc.com,
chenhuacai@...nel.org, kernel@...0n.name, geert@...ux-m68k.org,
sammy@...my.net, monstr@...str.eu, tsbogend@...ha.franken.de,
dinguyen@...nel.org, jonas@...thpole.se,
stefan.kristiansson@...nalahti.fi, shorne@...il.com,
James.Bottomley@...senPartnership.com, deller@....de,
mpe@...erman.id.au, npiggin@...il.com, christophe.leroy@...roup.eu,
paul.walmsley@...ive.com, palmer@...belt.com,
aou@...s.berkeley.edu, hca@...ux.ibm.com, gor@...ux.ibm.com,
agordeev@...ux.ibm.com, borntraeger@...ux.ibm.com,
svens@...ux.ibm.com, ysato@...rs.sourceforge.jp, dalias@...c.org,
davem@...emloft.net, richard@....at,
anton.ivanov@...bridgegreys.com, johannes@...solutions.net,
tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com,
acme@...nel.org, mark.rutland@....com,
alexander.shishkin@...ux.intel.com, jolsa@...nel.org,
namhyung@...nel.org, jgross@...e.com, srivatsa@...il.mit.edu,
amakhalov@...are.com, pv-drivers@...are.com,
boris.ostrovsky@...cle.com, chris@...kel.net, jcmvbkbc@...il.com,
rafael@...nel.org, lenb@...nel.org, pavel@....cz,
gregkh@...uxfoundation.org, mturquette@...libre.com,
sboyd@...nel.org, daniel.lezcano@...aro.org, lpieralisi@...nel.org,
sudeep.holla@....com, agross@...nel.org,
bjorn.andersson@...aro.org, konrad.dybcio@...ainline.org,
anup@...infault.org, thierry.reding@...il.com,
jonathanh@...dia.com, jacob.jun.pan@...ux.intel.com,
atishp@...shpatra.org, Arnd Bergmann <arnd@...db.de>,
yury.norov@...il.com, andriy.shevchenko@...ux.intel.com,
linux@...musvillemoes.dk, dennis@...nel.org, tj@...nel.org,
cl@...ux.com, rostedt@...dmis.org, pmladek@...e.com,
senozhatsky@...omium.org, john.ogness@...utronix.de,
juri.lelli@...hat.com, vincent.guittot@...aro.org,
dietmar.eggemann@....com, bsegall@...gle.com, mgorman@...e.de,
bristot@...hat.com, vschneid@...hat.com, fweisbec@...il.com,
ryabinin.a.a@...il.com, glider@...gle.com, andreyknvl@...il.com,
dvyukov@...gle.com, vincenzo.frascino@....com,
Andrew Morton <akpm@...ux-foundation.org>, jpoimboe@...nel.org,
linux-alpha@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-snps-arc@...ts.infradead.org, linux-omap@...r.kernel.org,
linux-csky@...r.kernel.org, linux-hexagon@...r.kernel.org,
linux-ia64@...r.kernel.org, loongarch@...ts.linux.dev,
linux-m68k@...ts.linux-m68k.org, linux-mips@...r.kernel.org,
openrisc@...ts.librecores.org, linux-parisc@...r.kernel.org,
linuxppc-dev@...ts.ozlabs.org, linux-riscv@...ts.infradead.org,
linux-s390@...r.kernel.org, linux-sh@...r.kernel.org,
sparclinux@...r.kernel.org, linux-um@...ts.infradead.org,
linux-perf-users@...r.kernel.org,
virtualization@...ts.linux-foundation.org,
linux-xtensa@...ux-xtensa.org, linux-acpi@...r.kernel.org,
linux-pm@...r.kernel.org, linux-clk@...r.kernel.org,
linux-arm-msm@...r.kernel.org, linux-tegra@...r.kernel.org,
linux-arch@...r.kernel.org, kasan-dev@...glegroups.com,
"Gautham R. Shenoy" <gautham.shenoy@....com>,
"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Subject: [PATCH v2 21/44] arch/idle: Change arch_cpu_idle() IRQ behaviour
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) <peterz@...radead.org>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@....com>
Acked-by: Mark Rutland <mark.rutland@....com> [arm64]
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
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(-)
--- 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)
--- 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
--- 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)
--- 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)
--- 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();
}
--- 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
--- 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"
--- 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();
}
/*
--- 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);
--- 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();
}
--- a/arch/microblaze/kernel/process.c
+++ b/arch/microblaze/kernel/process.c
@@ -140,5 +140,4 @@ int dump_fpu(struct pt_regs *regs, elf_f
void arch_cpu_idle(void)
{
- raw_local_irq_enable();
}
--- 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(v
" 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
--- 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();
}
/*
--- 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;
--- a/arch/parisc/kernel/process.c
+++ b/arch/parisc/kernel/process.c
@@ -187,8 +187,6 @@ 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":::);
}
--- 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.
--- a/arch/riscv/kernel/process.c
+++ b/arch/riscv/kernel/process.c
@@ -39,7 +39,6 @@ extern asmlinkage void ret_from_kernel_t
void arch_cpu_idle(void)
{
cpu_do_idle();
- raw_local_irq_enable();
}
void __show_regs(struct pt_regs *regs)
--- 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,
--- 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();
}
--- 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 */
--- 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. */
--- 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();
}
}
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -217,7 +217,6 @@ 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) {
--- a/arch/x86/coco/tdx/tdx.c
+++ b/arch/x86/coco/tdx/tdx.c
@@ -223,6 +223,9 @@ 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)
--- 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();
}
--- a/arch/xtensa/kernel/process.c
+++ b/arch/xtensa/kernel/process.c
@@ -183,6 +183,7 @@ void coprocessor_flush_release_all(struc
void arch_cpu_idle(void)
{
platform_idle();
+ raw_local_irq_disable();
}
/*
--- 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();
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