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 <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index d592dbb1d12a..b7f2963693a7 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();
 }
 
 /**