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intel_idle: Fix intel_idle() vs tracing 

commit 6e1d2bc675 upstream.

cpuidle->enter() callbacks should not call into tracing because RCU
has already been disabled. Instead of doing the broadcast thing
itself, simply advertise to the cpuidle core that those states stop
the timer.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lkml.kernel.org/r/20201123143510.GR3021@hirez.programming.kicks-ass.net
Signed-off-by: Chen Zhuo <sagazchen@tencent.com>
Signed-off-by: Xinghui Li <korantli@tencent.com>
This commit is contained in:
Peter Zijlstra 2020-11-20 11:28:35 +01:00 committed by Jianping Liu
parent 24b0b982e5
commit 69a0944244
1 changed files with 20 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
drivers/idle/intel_idle.c
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@ -127,26 +127,9 @@ static __cpuidle int intel_idle(struct cpuidle_device *dev,
struct cpuidle_state *state = &drv->states[index]; struct cpuidle_state *state = &drv->states[index];
unsigned long eax = flg2MWAIT(state->flags); unsigned long eax = flg2MWAIT(state->flags);
unsigned long ecx = 1; /* break on interrupt flag */ unsigned long ecx = 1; /* break on interrupt flag */
bool uninitialized_var(tick);
if (!static_cpu_has(X86_FEATURE_ARAT) && !lapic_timer_always_reliable) {
/*
* Switch over to one-shot tick broadcast if the target C-state
* is deeper than C1.
*/
if ((eax >> MWAIT_SUBSTATE_SIZE) & MWAIT_CSTATE_MASK) {
tick = true;
tick_broadcast_enter();
} else {
tick = false;
}
}
mwait_idle_with_hints(eax, ecx); mwait_idle_with_hints(eax, ecx);
if (!static_cpu_has(X86_FEATURE_ARAT) && tick)
tick_broadcast_exit();
return index; return index;
} }
@ -1229,6 +1212,20 @@ static bool __init intel_idle_acpi_cst_extract(void)
return false; return false;
} }
static bool __init intel_idle_state_needs_timer_stop(struct cpuidle_state *state)
{
unsigned long eax = flg2MWAIT(state->flags);
if (boot_cpu_has(X86_FEATURE_ARAT))
return false;
/*
* Switch over to one-shot tick broadcast if the target C-state
* is deeper than C1.
*/
return !!((eax >> MWAIT_SUBSTATE_SIZE) & MWAIT_CSTATE_MASK);
}
static void __init intel_idle_init_cstates_acpi(struct cpuidle_driver *drv) static void __init intel_idle_init_cstates_acpi(struct cpuidle_driver *drv)
{ {
int cstate, limit = min_t(int, CPUIDLE_STATE_MAX, acpi_state_table.count); int cstate, limit = min_t(int, CPUIDLE_STATE_MAX, acpi_state_table.count);
@ -1271,6 +1268,9 @@ static void __init intel_idle_init_cstates_acpi(struct cpuidle_driver *drv)
if (disabled_states_mask & BIT(cstate)) if (disabled_states_mask & BIT(cstate))
state->flags |= CPUIDLE_FLAG_OFF; state->flags |= CPUIDLE_FLAG_OFF;
if (intel_idle_state_needs_timer_stop(state))
state->flags |= CPUIDLE_FLAG_TIMER_STOP;
state->enter = intel_idle; state->enter = intel_idle;
state->enter_s2idle = intel_idle_s2idle; state->enter_s2idle = intel_idle_s2idle;
} }
@ -1524,6 +1524,9 @@ static void __init intel_idle_init_cstates_icpu(struct cpuidle_driver *drv)
!(cpuidle_state_table[cstate].flags & CPUIDLE_FLAG_ALWAYS_ENABLE))) !(cpuidle_state_table[cstate].flags & CPUIDLE_FLAG_ALWAYS_ENABLE)))
drv->states[drv->state_count].flags |= CPUIDLE_FLAG_OFF; drv->states[drv->state_count].flags |= CPUIDLE_FLAG_OFF;
if (intel_idle_state_needs_timer_stop(&drv->states[drv->state_count]))
drv->states[drv->state_count].flags |= CPUIDLE_FLAG_TIMER_STOP;
drv->state_count++; drv->state_count++;
} }