diff options
Diffstat (limited to 'arch/i386/kernel/process.c')
| -rw-r--r-- | arch/i386/kernel/process.c | 39 |
1 files changed, 37 insertions, 2 deletions
diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c index aea2ce1145d..5f8cfa6b794 100644 --- a/arch/i386/kernel/process.c +++ b/arch/i386/kernel/process.c @@ -13,6 +13,7 @@ #include <stdarg.h> +#include <linux/cpu.h> #include <linux/errno.h> #include <linux/sched.h> #include <linux/fs.h> @@ -55,6 +56,9 @@ #include <linux/irq.h> #include <linux/err.h> +#include <asm/tlbflush.h> +#include <asm/cpu.h> + asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); static int hlt_counter; @@ -143,14 +147,42 @@ static void poll_idle (void) } } +#ifdef CONFIG_HOTPLUG_CPU +#include <asm/nmi.h> +/* We don't actually take CPU down, just spin without interrupts. */ +static inline void play_dead(void) +{ + /* This must be done before dead CPU ack */ + cpu_exit_clear(); + wbinvd(); + mb(); + /* Ack it */ + __get_cpu_var(cpu_state) = CPU_DEAD; + + /* + * With physical CPU hotplug, we should halt the cpu + */ + local_irq_disable(); + while (1) + __asm__ __volatile__("hlt":::"memory"); +} +#else +static inline void play_dead(void) +{ + BUG(); +} +#endif /* CONFIG_HOTPLUG_CPU */ + /* * The idle thread. There's no useful work to be * done, so just try to conserve power and have a * low exit latency (ie sit in a loop waiting for * somebody to say that they'd like to reschedule) */ -void cpu_idle (void) +void cpu_idle(void) { + int cpu = raw_smp_processor_id(); + /* endless idle loop with no priority at all */ while (1) { while (!need_resched()) { @@ -165,6 +197,9 @@ void cpu_idle (void) if (!idle) idle = default_idle; + if (cpu_is_offline(cpu)) + play_dead(); + __get_cpu_var(irq_stat).idle_timestamp = jiffies; idle(); } @@ -223,7 +258,7 @@ static void mwait_idle(void) } } -void __init select_idle_routine(const struct cpuinfo_x86 *c) +void __devinit select_idle_routine(const struct cpuinfo_x86 *c) { if (cpu_has(c, X86_FEATURE_MWAIT)) { printk("monitor/mwait feature present.\n"); |