From dcf309974555d17019c6a8e1a425238f17990b71 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 25 Jul 2008 18:00:42 -0400 Subject: ftrace: disable tracing on acpi idle calls The acpi idle waits calls local_irq_save and then uses mwait to go into idle. The tracer gets reenabled at local_irq_save but does not detect that the idle allows for wake ups. This patch adds code to disable the tracing when acpi puts the CPU to idle. Signed-off-by: Steven Rostedt Cc: Peter Zijlstra Signed-off-by: Ingo Molnar --- drivers/acpi/processor_idle.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'drivers/acpi/processor_idle.c') diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index d592dbb1d12..b7f2963693a 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -272,6 +272,8 @@ static atomic_t c3_cpu_count; /* Common C-state entry for C2, C3, .. */ static void acpi_cstate_enter(struct acpi_processor_cx *cstate) { + /* Don't trace irqs off for idle */ + stop_critical_timings(); if (cstate->entry_method == ACPI_CSTATE_FFH) { /* Call into architectural FFH based C-state */ acpi_processor_ffh_cstate_enter(cstate); @@ -284,6 +286,7 @@ static void acpi_cstate_enter(struct acpi_processor_cx *cstate) gets asserted in time to freeze execution properly. */ unused = inl(acpi_gbl_FADT.xpm_timer_block.address); } + start_critical_timings(); } #endif /* !CONFIG_CPU_IDLE */ @@ -1418,6 +1421,8 @@ static inline void acpi_idle_update_bm_rld(struct acpi_processor *pr, */ static inline void acpi_idle_do_entry(struct acpi_processor_cx *cx) { + /* Don't trace irqs off for idle */ + stop_critical_timings(); if (cx->entry_method == ACPI_CSTATE_FFH) { /* Call into architectural FFH based C-state */ acpi_processor_ffh_cstate_enter(cx); @@ -1432,6 +1437,7 @@ static inline void acpi_idle_do_entry(struct acpi_processor_cx *cx) gets asserted in time to freeze execution properly. */ unused = inl(acpi_gbl_FADT.xpm_timer_block.address); } + start_critical_timings(); } /** -- cgit v1.2.3-70-g09d2 From b032bf70df2e43149ce2b4e9a865b076c6140753 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sun, 27 Jul 2008 23:47:12 +0200 Subject: ACPI/CPUIDLE: prevent setting pm_idle to NULL pm_idle_save resp. pm_idle_old can be NULL when the restore code in acpi_processor_cst_has_changed() resp. cpuidle_uninstall_idle_handler() is called. This can set pm_idle unconditinally to NULL, which causes the kernel to panic when calling pm_idle in the x86 idle code. This was covered by an extra check for !pm_idle in the x86 idle code, which was removed during the x86 idle code refactoring. Instead of restoring the pm_idle check in the x86 code prevent the acpi/cpuidle code to set pm_idle to NULL. Reported by: Dhaval Giani http://lkml.org/lkml/2008/7/2/309 Based on a debug patch from Ingo Molnar Signed-off-by: Thomas Gleixner Signed-off-by: Linus Torvalds --- drivers/acpi/processor_idle.c | 15 +++++++++++---- drivers/cpuidle/cpuidle.c | 2 +- 2 files changed, 12 insertions(+), 5 deletions(-) (limited to 'drivers/acpi/processor_idle.c') diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index b7f2963693a..283c08f5f4d 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -1332,9 +1332,15 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr) if (!pr->flags.power_setup_done) return -ENODEV; - /* Fall back to the default idle loop */ - pm_idle = pm_idle_save; - synchronize_sched(); /* Relies on interrupts forcing exit from idle. */ + /* + * Fall back to the default idle loop, when pm_idle_save had + * been initialized. + */ + if (pm_idle_save) { + pm_idle = pm_idle_save; + /* Relies on interrupts forcing exit from idle. */ + synchronize_sched(); + } pr->flags.power = 0; result = acpi_processor_get_power_info(pr); @@ -1896,7 +1902,8 @@ int acpi_processor_power_exit(struct acpi_processor *pr, /* Unregister the idle handler when processor #0 is removed. */ if (pr->id == 0) { - pm_idle = pm_idle_save; + if (pm_idle_save) + pm_idle = pm_idle_save; /* * We are about to unload the current idle thread pm callback diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index 5405769020a..5ce07b517c5 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -94,7 +94,7 @@ void cpuidle_install_idle_handler(void) */ void cpuidle_uninstall_idle_handler(void) { - if (enabled_devices && (pm_idle != pm_idle_old)) { + if (enabled_devices && pm_idle_old && (pm_idle != pm_idle_old)) { pm_idle = pm_idle_old; cpuidle_kick_cpus(); } -- cgit v1.2.3-70-g09d2