From b2d8b0cb6ca9cb81dd71626642f764ac70d10813 Mon Sep 17 00:00:00 2001
From: James Morse <james.morse@arm.com>
Date: Wed, 17 Aug 2016 13:50:27 +0100
Subject: Revert "arm64: hibernate: Refuse to hibernate if the boot cpu is
 offline"

Now that we use the MPIDR to resume on the same CPU that we hibernated on,
we no longer need to refuse to hibernate if the boot cpu is offline. (Which
we can't possibly know if kexec causes logical CPUs to be renumbered).

This reverts commit 1fe492ce6482b77807b25d29690a48c46456beee.

Signed-off-by: James Morse <james.morse@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
index 3c74b9f..d55a7b0 100644
--- a/arch/arm64/kernel/hibernate.c
+++ b/arch/arm64/kernel/hibernate.c
@@ -18,7 +18,6 @@
 #include <linux/cpu.h>
 #include <linux/kvm_host.h>
 #include <linux/mm.h>
-#include <linux/notifier.h>
 #include <linux/pm.h>
 #include <linux/sched.h>
 #include <linux/suspend.h>
@@ -545,31 +544,6 @@ out:
 	return rc;
 }
 
-static int check_boot_cpu_online_pm_callback(struct notifier_block *nb,
-					     unsigned long action, void *ptr)
-{
-	if (action == PM_HIBERNATION_PREPARE &&
-	     cpumask_first(cpu_online_mask) != 0) {
-		pr_warn("CPU0 is offline.\n");
-		return notifier_from_errno(-ENODEV);
-	}
-
-	return NOTIFY_OK;
-}
-
-static int __init check_boot_cpu_online_init(void)
-{
-	/*
-	 * Set this pm_notifier callback with a lower priority than
-	 * cpu_hotplug_pm_callback, so that cpu_hotplug_pm_callback will be
-	 * called earlier to disable cpu hotplug before the cpu online check.
-	 */
-	pm_notifier(check_boot_cpu_online_pm_callback, -INT_MAX);
-
-	return 0;
-}
-core_initcall(check_boot_cpu_online_init);
-
 int hibernate_resume_nonboot_cpu_disable(void)
 {
 	if (sleep_cpu < 0) {
-- 
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