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Subject[PATCH v3 7/7] x86/power/cpu.c: Don't hibernate/suspend if CPU0 is offline
Date
From: Fenghua Yu <fenghua.yu@intel.com>

Because x86 BIOS requires CPU0 to resume from sleep, suspend or hibernate
can't be executed if CPU0 is detected offline.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
---
arch/x86/power/cpu.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 44 insertions(+), 0 deletions(-)

diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index f10c0af..a4ec084 100644
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -236,3 +236,47 @@ void restore_processor_state(void)
#ifdef CONFIG_X86_32
EXPORT_SYMBOL(restore_processor_state);
#endif
+
+/*
+ * When bsp_check() is called in hibernate and suspend, cpu hotplug
+ * is disabled already. So it's unnessary to handle race condition between
+ * cpumask query and cpu hotplug.
+ */
+static int bsp_check(void)
+{
+ if (cpumask_first(cpu_online_mask) != 0) {
+ printk(KERN_WARNING "CPU0 is offline.\n");
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
+static int bsp_pm_callback(struct notifier_block *nb, unsigned long action,
+ void *ptr)
+{
+ int ret = 0;
+
+ switch (action) {
+ case PM_SUSPEND_PREPARE:
+ case PM_HIBERNATION_PREPARE:
+ ret = bsp_check();
+ break;
+ default:
+ break;
+ }
+ return notifier_from_errno(ret);
+}
+
+static int __init bsp_pm_check_init(void)
+{
+ /*
+ * Set this bsp_pm_callback as lower priority than
+ * cpu_hotplug_pm_callback. So cpu_hotplug_pm_callback will be called
+ * earlier to disable cpu hotplug before bsp online check.
+ */
+ pm_notifier(bsp_pm_callback, -INT_MAX);
+ return 0;
+}
+
+core_initcall(bsp_pm_check_init);
--
1.6.0.3


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