From: Li Shaohua 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 --- drivers/acpi/Kconfig | 2 - include/linux/suspend.h | 2 - kernel/power/Kconfig | 2 - kernel/power/disk.c | 36 ++++++++++-------- kernel/power/main.c | 16 +++++--- kernel/power/smp.c | 91 ++++++++++++++++++------------------------------ kernel/power/swsusp.c | 2 + 7 files changed, 69 insertions(+), 82 deletions(-) diff -puN drivers/acpi/Kconfig~suspend-resume-smp-support drivers/acpi/Kconfig --- 25/drivers/acpi/Kconfig~suspend-resume-smp-support 2005-05-09 19:57:41.000000000 -0700 +++ 25-akpm/drivers/acpi/Kconfig 2005-05-09 19:57:41.000000000 -0700 @@ -56,7 +56,7 @@ if ACPI_INTERPRETER config ACPI_SLEEP bool "Sleep States (EXPERIMENTAL)" - depends on X86 + depends on X86 && (!SMP || HOTPLUG_CPU) depends on EXPERIMENTAL default y ---help--- diff -puN include/linux/suspend.h~suspend-resume-smp-support include/linux/suspend.h --- 25/include/linux/suspend.h~suspend-resume-smp-support 2005-05-09 19:57:41.000000000 -0700 +++ 25-akpm/include/linux/suspend.h 2005-05-09 19:57:41.000000000 -0700 @@ -58,7 +58,7 @@ static inline int software_suspend(void) } #endif -#ifdef CONFIG_SMP +#ifdef CONFIG_HOTPLUG_CPU extern void disable_nonboot_cpus(void); extern void enable_nonboot_cpus(void); #else diff -puN kernel/power/disk.c~suspend-resume-smp-support kernel/power/disk.c --- 25/kernel/power/disk.c~suspend-resume-smp-support 2005-05-09 19:57:41.000000000 -0700 +++ 25-akpm/kernel/power/disk.c 2005-05-09 19:57:41.000000000 -0700 @@ -117,8 +117,8 @@ static void finish(void) { device_resume(); platform_finish(); - enable_nonboot_cpus(); thaw_processes(); + enable_nonboot_cpus(); pm_restore_console(); } @@ -131,28 +131,36 @@ static int prepare_processes(void) sys_sync(); + disable_nonboot_cpus(); + if (freeze_processes()) { error = -EBUSY; - return error; + goto enable_cpu; } if (pm_disk_mode == PM_DISK_PLATFORM) { if (pm_ops && pm_ops->prepare) { if ((error = pm_ops->prepare(PM_SUSPEND_DISK))) - return error; + goto thaw; } } /* Free memory before shutting down devices. */ free_some_memory(); - return 0; +thaw: + thaw_processes(); +enable_cpu: + enable_nonboot_cpus(); + pm_restore_console(); + return error; } static void unprepare_processes(void) { - enable_nonboot_cpus(); + platform_finish(); thaw_processes(); + enable_nonboot_cpus(); pm_restore_console(); } @@ -160,15 +168,9 @@ static int prepare_devices(void) { int error; - disable_nonboot_cpus(); - if ((error = device_suspend(PMSG_FREEZE))) { + if ((error = device_suspend(PMSG_FREEZE))) printk("Some devices failed to suspend\n"); - platform_finish(); - enable_nonboot_cpus(); - return error; - } - - return 0; + return error; } /** @@ -185,9 +187,9 @@ int pm_suspend_disk(void) int error; error = prepare_processes(); - if (!error) { - error = prepare_devices(); - } + if (error) + return error; + error = prepare_devices(); if (error) { unprepare_processes(); @@ -250,7 +252,7 @@ static int software_resume(void) if ((error = prepare_processes())) { swsusp_close(); - goto Cleanup; + goto Done; } pr_debug("PM: Reading swsusp image.\n"); diff -puN kernel/power/Kconfig~suspend-resume-smp-support kernel/power/Kconfig --- 25/kernel/power/Kconfig~suspend-resume-smp-support 2005-05-09 19:57:41.000000000 -0700 +++ 25-akpm/kernel/power/Kconfig 2005-05-09 19:57:41.000000000 -0700 @@ -28,7 +28,7 @@ config PM_DEBUG config SOFTWARE_SUSPEND bool "Software Suspend (EXPERIMENTAL)" - depends on EXPERIMENTAL && PM && SWAP + depends on EXPERIMENTAL && PM && SWAP && (HOTPLUG_CPU || !SMP) ---help--- Enable the possibility of suspending the machine. It doesn't need APM. diff -puN kernel/power/main.c~suspend-resume-smp-support kernel/power/main.c --- 25/kernel/power/main.c~suspend-resume-smp-support 2005-05-09 19:57:41.000000000 -0700 +++ 25-akpm/kernel/power/main.c 2005-05-09 19:57:57.000000000 -0700 @@ -59,6 +59,13 @@ static int suspend_prepare(suspend_state pm_prepare_console(); + disable_nonboot_cpus(); + + if (num_online_cpus() != 1) { + error = -EPERM; + goto Enable_cpu; + } + if (freeze_processes()) { error = -EAGAIN; goto Thaw; @@ -89,6 +96,8 @@ static int suspend_prepare(suspend_state pm_ops->finish(state); Thaw: thaw_processes(); + Enable_cpu: + enable_nonboot_cpus(); pm_restore_console(); return error; } @@ -127,6 +136,7 @@ static void suspend_finish(suspend_state if (pm_ops && pm_ops->finish) pm_ops->finish(state); thaw_processes(); + enable_nonboot_cpus(); pm_restore_console(); } @@ -164,12 +174,6 @@ static int enter_state(suspend_state_t s goto Unlock; } - /* Suspend is hard to get right on SMP. */ - if (num_online_cpus() != 1) { - error = -EPERM; - goto Unlock; - } - pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]); if ((error = suspend_prepare(state))) goto Unlock; diff -puN kernel/power/smp.c~suspend-resume-smp-support kernel/power/smp.c --- 25/kernel/power/smp.c~suspend-resume-smp-support 2005-05-09 19:57:41.000000000 -0700 +++ 25-akpm/kernel/power/smp.c 2005-05-09 19:57:41.000000000 -0700 @@ -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)", _smp_processor_id()); - current->state = TASK_INTERRUPTIBLE; - schedule_timeout(HZ); - printk("..."); - BUG_ON(_smp_processor_id() != 0); - - /* FIXME: for this to work, all the CPUs must be running - * "idle" thread (or we deadlock). Is that guaranteed? */ - - 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(); + int cpu, error; + + 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); } - diff -puN kernel/power/swsusp.c~suspend-resume-smp-support kernel/power/swsusp.c --- 25/kernel/power/swsusp.c~suspend-resume-smp-support 2005-05-09 19:57:41.000000000 -0700 +++ 25-akpm/kernel/power/swsusp.c 2005-05-09 19:57:41.000000000 -0700 @@ -1193,8 +1193,10 @@ static const char * sanity_check(void) return "version"; if (strcmp(swsusp_info.uts.machine,system_utsname.machine)) return "machine"; +#if 0 if(swsusp_info.cpus != num_online_cpus()) return "number of cpus"; +#endif return NULL; } _