As per the (somewhat recent) comment before the definition of
`__cpuidle`, the tag is like `noinstr` but also marks a function so it
can be identified by cpu_in_idle(). Let'a add this.
After doing this then when we dump stack traces of all processors
using nmi_cpu_backtrace() then instead of getting useless backtraces
we get things like:
NMI backtrace for cpu N skipped: idling at cpu_do_idle+0x94/0x98
NOTE: this patch won't make cpu_in_idle() work perfectly for arm64,
but it doesn't hurt and does catch some cases. Specifically an example
that wasn't caught in my testing looked like this:
gic_cpu_sys_reg_init+0x1f8/0x314
gic_cpu_pm_notifier+0x40/0x78
raw_notifier_call_chain+0x5c/0x134
cpu_pm_notify+0x38/0x64
cpu_pm_exit+0x20/0x2c
psci_enter_idle_state+0x48/0x70
cpuidle_enter_state+0xb8/0x260
cpuidle_enter+0x44/0x5c
do_idle+0x188/0x30c
Signed-off-by: Douglas Anderson <diand...@chromium.org>
---
Changes in v9:
- Added to commit message that this doesn't catch all cases.
Changes in v8:
- "Tag the arm64 idle functions as __cpuidle" new for v8
arch/arm64/kernel/idle.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kernel/idle.c b/arch/arm64/kernel/idle.c
index c1125753fe9b..05cfb347ec26 100644
--- a/arch/arm64/kernel/idle.c
+++ b/arch/arm64/kernel/idle.c
@@ -20,7 +20,7 @@
* ensure that interrupts are not masked at the PMR (because the core will
* not wake up if we block the wake up signal in the interrupt controller).
*/
-void noinstr cpu_do_idle(void)
+void __cpuidle cpu_do_idle(void)
{
struct arm_cpuidle_irq_context context;
@@ -35,7 +35,7 @@ void noinstr cpu_do_idle(void)
/*
* This is our default idle handler.
*/
-void noinstr arch_cpu_idle(void)
+void __cpuidle arch_cpu_idle(void)
{
/*
* This should do all the clock switching and wait for interrupt
--
2.41.0.rc2.161.g9c6817b8e7-goog
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