From 4e0ba5577dba686f96c1c10ef4166380667fdec7 Mon Sep 17 00:00:00 2001 From: Chen Yu Date: Sun, 25 Oct 2020 00:29:53 +0800 Subject: intel_idle: Fix max_cstate for processor models without C-state tables Currently intel_idle driver gets the c-state information from ACPI _CST if the processor model is not recognized by it. However the c-state in _CST starts with index 1 which is different from the index in intel_idle driver's internal c-state table. While intel_idle_max_cstate_reached() was previously introduced to deal with intel_idle driver's internal c-state table, re-using this function directly on _CST is incorrect. Fix this by subtracting 1 from the index when checking max_cstate in the _CST case. For example, append intel_idle.max_cstate=1 in boot command line, Before the patch: grep . /sys/devices/system/cpu/cpu0/cpuidle/state*/name POLL After the patch: grep . /sys/devices/system/cpu/cpu0/cpuidle/state*/name /sys/devices/system/cpu/cpu0/cpuidle/state0/name:POLL /sys/devices/system/cpu/cpu0/cpuidle/state1/name:C1_ACPI Fixes: 18734958e9bf ("intel_idle: Use ACPI _CST for processor models without C-state tables") Reported-by: Pengfei Xu Cc: 5.6+ # 5.6+ Signed-off-by: Chen Yu [ rjw: Changelog edits ] Signed-off-by: Rafael J. Wysocki --- drivers/idle/intel_idle.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/idle/intel_idle.c') diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 56f5b8077cba..01bace49a962 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -1239,7 +1239,7 @@ static void __init intel_idle_init_cstates_acpi(struct cpuidle_driver *drv) struct acpi_processor_cx *cx; struct cpuidle_state *state; - if (intel_idle_max_cstate_reached(cstate)) + if (intel_idle_max_cstate_reached(cstate - 1)) break; cx = &acpi_state_table.states[cstate]; -- cgit v1.2.3 From 6e1d2bc675bd57640f5658a4a657ae488db4c204 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 20 Nov 2020 11:28:35 +0100 Subject: 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) Acked-by: Rafael J. Wysocki Link: https://lkml.kernel.org/r/20201123143510.GR3021@hirez.programming.kicks-ass.net --- drivers/idle/intel_idle.c | 37 ++++++++++++++++++++----------------- 1 file changed, 20 insertions(+), 17 deletions(-) (limited to 'drivers/idle/intel_idle.c') 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++; } -- cgit v1.2.3