diff options
| -rw-r--r-- | include/linux/cpu.h | 1 | ||||
| -rw-r--r-- | kernel/cpu.c | 23 |
2 files changed, 24 insertions, 0 deletions
diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 64a246e9c8db..9dc1e892e193 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -93,6 +93,7 @@ int add_cpu(unsigned int cpu); void notify_cpu_starting(unsigned int cpu); extern void cpu_maps_update_begin(void); extern void cpu_maps_update_done(void); +int bringup_hibernate_cpu(unsigned int sleep_cpu); #else /* CONFIG_SMP */ #define cpuhp_tasks_frozen 0 diff --git a/kernel/cpu.c b/kernel/cpu.c index 03c727195b65..f803678684e9 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -1275,6 +1275,29 @@ int add_cpu(unsigned int cpu) } EXPORT_SYMBOL_GPL(add_cpu); +/** + * bringup_hibernate_cpu - Bring up the CPU that we hibernated on + * @sleep_cpu: The cpu we hibernated on and should be brought up. + * + * On some architectures like arm64, we can hibernate on any CPU, but on + * wake up the CPU we hibernated on might be offline as a side effect of + * using maxcpus= for example. + */ +int bringup_hibernate_cpu(unsigned int sleep_cpu) +{ + int ret; + + if (!cpu_online(sleep_cpu)) { + pr_info("Hibernated on a CPU that is offline! Bringing CPU up.\n"); + ret = cpu_up(sleep_cpu); + if (ret) { + pr_err("Failed to bring hibernate-CPU up!\n"); + return ret; + } + } + return 0; +} + #ifdef CONFIG_PM_SLEEP_SMP static cpumask_var_t frozen_cpus; |