From 69a09442447b23f8d312d434802d57cff27bbb07 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 20 Nov 2020 11:28:35 +0100 Subject: [PATCH] intel_idle: Fix intel_idle() vs tracing commit 6e1d2bc675bd57640f5658a4a657ae488db4c204 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) Acked-by: Rafael J. Wysocki Link: https://lkml.kernel.org/r/20201123143510.GR3021@hirez.programming.kicks-ass.net Signed-off-by: Chen Zhuo Signed-off-by: Xinghui Li --- drivers/idle/intel_idle.c | 37 ++++++++++++++++++++----------------- 1 file changed, 20 insertions(+), 17 deletions(-) diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 6d3ac05f5e8b..b13e84bf41a7 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -127,26 +127,9 @@ 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 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); - if (!static_cpu_has(X86_FEATURE_ARAT) && tick) - tick_broadcast_exit(); - return index; } @@ -1229,6 +1212,20 @@ 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); @@ -1271,6 +1268,9 @@ 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; } @@ -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))) 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++; }