diff options
Diffstat (limited to 'arch/x86_64/kernel/process.c')
| -rw-r--r-- | arch/x86_64/kernel/process.c | 51 |
1 files changed, 29 insertions, 22 deletions
diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c index 7451a4c43c1..cbbc6adc1a9 100644 --- a/arch/x86_64/kernel/process.c +++ b/arch/x86_64/kernel/process.c @@ -108,17 +108,19 @@ void exit_idle(void) */ static void default_idle(void) { - local_irq_enable(); - current_thread_info()->status &= ~TS_POLLING; - smp_mb__after_clear_bit(); - while (!need_resched()) { - local_irq_disable(); - if (!need_resched()) - safe_halt(); - else - local_irq_enable(); - } + /* + * TS_POLLING-cleared state must be visible before we + * test NEED_RESCHED: + */ + smp_mb(); + local_irq_disable(); + if (!need_resched()) { + /* Enables interrupts one instruction before HLT. + x86 special cases this so there is no race. */ + safe_halt(); + } else + local_irq_enable(); current_thread_info()->status |= TS_POLLING; } @@ -130,15 +132,7 @@ static void default_idle(void) static void poll_idle (void) { local_irq_enable(); - - asm volatile( - "2:" - "testl %0,%1;" - "rep; nop;" - "je 2b;" - : : - "i" (_TIF_NEED_RESCHED), - "m" (current_thread_info()->flags)); + cpu_relax(); } void cpu_idle_wait(void) @@ -219,6 +213,12 @@ void cpu_idle (void) idle = default_idle; if (cpu_is_offline(smp_processor_id())) play_dead(); + /* + * Idle routines should keep interrupts disabled + * from here on, until they go to idle. + * Otherwise, idle callbacks can misfire. + */ + local_irq_disable(); enter_idle(); idle(); /* In many cases the interrupt that ended idle @@ -256,9 +256,16 @@ void mwait_idle_with_hints(unsigned long eax, unsigned long ecx) /* Default MONITOR/MWAIT with no hints, used for default C1 state */ static void mwait_idle(void) { - local_irq_enable(); - while (!need_resched()) - mwait_idle_with_hints(0,0); + if (!need_resched()) { + __monitor((void *)¤t_thread_info()->flags, 0, 0); + smp_mb(); + if (!need_resched()) + __sti_mwait(0, 0); + else + local_irq_enable(); + } else { + local_irq_enable(); + } } void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c) |