1 files changed, 23 insertions, 0 deletions
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;