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authorPeter Zijlstra <peterz@infradead.org>2020-11-20 11:28:35 +0100
committerPeter Zijlstra <peterz@infradead.org>2020-11-24 16:47:36 +0100
commit6e1d2bc675bd57640f5658a4a657ae488db4c204 (patch)
tree2184496c918031ffc2b71eba9a6ba4c9b2e457a3 /drivers/idle
parent58c644ba512cfbc2e39b758dd979edd1d6d00e27 (diff)
intel_idle: Fix intel_idle() vs tracing
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
Diffstat (limited to 'drivers/idle')
-rw-r--r--drivers/idle/intel_idle.c37
1 files changed, 20 insertions, 17 deletions
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index 01bace49a962..7ee7ffe22ae3 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -126,26 +126,9 @@ static __cpuidle int intel_idle(struct cpuidle_device *dev,
struct cpuidle_state *state = &drv->states[index];
unsigned long eax = flg2MWAIT(state->flags);
unsigned long ecx = 1; /* break on interrupt flag */
- bool tick;
-
- if (!static_cpu_has(X86_FEATURE_ARAT)) {
- /*
- * 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);
- if (!static_cpu_has(X86_FEATURE_ARAT) && tick)
- tick_broadcast_exit();
-
return index;
}
@@ -1227,6 +1210,20 @@ static bool __init intel_idle_acpi_cst_extract(void)
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)
{
int cstate, limit = min_t(int, CPUIDLE_STATE_MAX, acpi_state_table.count);
@@ -1269,6 +1266,9 @@ static void __init intel_idle_init_cstates_acpi(struct cpuidle_driver *drv)
if (disabled_states_mask & BIT(cstate))
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_s2idle = intel_idle_s2idle;
}
@@ -1507,6 +1507,9 @@ static void __init intel_idle_init_cstates_icpu(struct cpuidle_driver *drv)
!(cpuidle_state_table[cstate].flags & CPUIDLE_FLAG_ALWAYS_ENABLE)))
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++;
}