diff options
Diffstat (limited to 'arch/i386/kernel/process.c')
| -rw-r--r-- | arch/i386/kernel/process.c | 28 |
1 files changed, 20 insertions, 8 deletions
diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c index dad02a960e03..57d375900afb 100644 --- a/arch/i386/kernel/process.c +++ b/arch/i386/kernel/process.c @@ -236,20 +236,28 @@ EXPORT_SYMBOL_GPL(cpu_idle_wait); * We execute MONITOR against need_resched and enter optimized wait state * through MWAIT. Whenever someone changes need_resched, we would be woken * up from MWAIT (without an IPI). + * + * New with Core Duo processors, MWAIT can take some hints based on CPU + * capability. */ -static void mwait_idle(void) +void mwait_idle_with_hints(unsigned long eax, unsigned long ecx) { - local_irq_enable(); - - while (!need_resched()) { + if (!need_resched()) { __monitor((void *)¤t_thread_info()->flags, 0, 0); smp_mb(); - if (need_resched()) - break; - __mwait(0, 0); + if (!need_resched()) + __mwait(eax, 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); +} + void __devinit select_idle_routine(const struct cpuinfo_x86 *c) { if (cpu_has(c, X86_FEATURE_MWAIT)) { @@ -328,6 +336,7 @@ extern void kernel_thread_helper(void); int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) { struct pt_regs regs; + int err; memset(®s, 0, sizeof(regs)); @@ -342,7 +351,10 @@ int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) regs.eflags = X86_EFLAGS_IF | X86_EFLAGS_SF | X86_EFLAGS_PF | 0x2; /* Ok, create the new process.. */ - return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); + err = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); + if (err == 0) /* terminate kernel stack */ + task_pt_regs(current)->eip = 0; + return err; } EXPORT_SYMBOL(kernel_thread); |
