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authorQais Yousef <[email protected]>2020-03-23 13:51:01 +0000
committerThomas Gleixner <[email protected]>2020-03-25 12:59:34 +0100
commitd720f98604391dab6aa3cb4c1bc005ed1aba4703 (patch)
tree4aa30be79a98f962c38b731a507add852860d9db
parent5efbe6a6e1c077b4022d9e89d79543c6106c6e25 (diff)
cpu/hotplug: Provide bringup_hibernate_cpu()
arm64 uses cpu_up() in the resume from hibernation code to ensure that the CPU on which the system hibernated is online. Provide a core function for this. [ tglx: Split out from the combo arm64 patch ] Signed-off-by: Qais Yousef <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Acked-by: Catalin Marinas <[email protected]> Cc: Will Deacon <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
-rw-r--r--include/linux/cpu.h1
-rw-r--r--kernel/cpu.c23
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;