diff options
Diffstat (limited to 'arch/i386/kernel/process.c')
| -rw-r--r-- | arch/i386/kernel/process.c | 39 |
1 files changed, 38 insertions, 1 deletions
diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c index aea2ce1145df..c1b11e8df60b 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 +147,44 @@ 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) +{ + /* Ack it */ + __get_cpu_var(cpu_state) = CPU_DEAD; + + /* We shouldn't have to disable interrupts while dead, but + * some interrupts just don't seem to go away, and this makes + * it "work" for testing purposes. */ + /* Death loop */ + while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE) + cpu_relax(); + + local_irq_disable(); + __flush_tlb_all(); + cpu_set(smp_processor_id(), cpu_online_map); + enable_APIC_timer(); + local_irq_enable(); +} +#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 +199,9 @@ 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(); } |