From 5a72e04df5470df0ec646029d31e5528167ab1a7 Mon Sep 17 00:00:00 2001 From: Li Shaohua Date: Sat, 25 Jun 2005 14:55:06 -0700 Subject: [PATCH] suspend/resume SMP support Using CPU hotplug to support suspend/resume SMP. Both S3 and S4 use disable/enable_nonboot_cpus API. The S4 part is based on Pavel's original S4 SMP patch. Signed-off-by: Li Shaohua Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/power/smp.c | 89 +++++++++++++++++++++--------------------------------- 1 file changed, 34 insertions(+), 55 deletions(-) (limited to 'kernel/power/smp.c') diff --git a/kernel/power/smp.c b/kernel/power/smp.c index 457c2302ed4..bbe23079c62 100644 --- a/kernel/power/smp.c +++ b/kernel/power/smp.c @@ -13,73 +13,52 @@ #include #include #include +#include #include #include -static atomic_t cpu_counter, freeze; - - -static void smp_pause(void * data) -{ - struct saved_context ctxt; - __save_processor_state(&ctxt); - printk("Sleeping in:\n"); - dump_stack(); - atomic_inc(&cpu_counter); - while (atomic_read(&freeze)) { - /* FIXME: restore takes place at random piece inside this. - This should probably be written in assembly, and - preserve general-purpose registers, too - - What about stack? We may need to move to new stack here. - - This should better be ran with interrupts disabled. - */ - cpu_relax(); - barrier(); - } - atomic_dec(&cpu_counter); - __restore_processor_state(&ctxt); -} - -static cpumask_t oldmask; +/* This is protected by pm_sem semaphore */ +static cpumask_t frozen_cpus; void disable_nonboot_cpus(void) { - oldmask = current->cpus_allowed; - set_cpus_allowed(current, cpumask_of_cpu(0)); - printk("Freezing CPUs (at %d)", raw_smp_processor_id()); - current->state = TASK_INTERRUPTIBLE; - schedule_timeout(HZ); - printk("..."); - BUG_ON(raw_smp_processor_id() != 0); - - /* FIXME: for this to work, all the CPUs must be running - * "idle" thread (or we deadlock). Is that guaranteed? */ + int cpu, error; - atomic_set(&cpu_counter, 0); - atomic_set(&freeze, 1); - smp_call_function(smp_pause, NULL, 0, 0); - while (atomic_read(&cpu_counter) < (num_online_cpus() - 1)) { - cpu_relax(); - barrier(); + error = 0; + cpus_clear(frozen_cpus); + printk("Freezing cpus ...\n"); + for_each_online_cpu(cpu) { + if (cpu == 0) + continue; + error = cpu_down(cpu); + if (!error) { + cpu_set(cpu, frozen_cpus); + printk("CPU%d is down\n", cpu); + continue; + } + printk("Error taking cpu %d down: %d\n", cpu, error); } - printk("ok\n"); + BUG_ON(smp_processor_id() != 0); + if (error) + panic("cpus not sleeping"); } void enable_nonboot_cpus(void) { - printk("Restarting CPUs"); - atomic_set(&freeze, 0); - while (atomic_read(&cpu_counter)) { - cpu_relax(); - barrier(); - } - printk("..."); - set_cpus_allowed(current, oldmask); - schedule(); - printk("ok\n"); + int cpu, error; + printk("Thawing cpus ...\n"); + for_each_cpu_mask(cpu, frozen_cpus) { + error = smp_prepare_cpu(cpu); + if (!error) + error = cpu_up(cpu); + if (!error) { + printk("CPU%d is up\n", cpu); + continue; + } + printk("Error taking cpu %d up: %d\n", cpu, error); + panic("Not enough cpus"); + } + cpus_clear(frozen_cpus); } - -- cgit v1.2.3-70-g09d2