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authorQais Yousef <qais.yousef@arm.com>2020-03-23 14:50:55 +0100
committerThomas Gleixner <tglx@linutronix.de>2020-03-25 12:59:31 +0100
commit0441a5597c5d02ed7abed1d989eaaa1595dedac5 (patch)
treed5014aec6251f4733d0740fc9a632850fad9d9a5 /kernel/cpu.c
parentcpu/hotplug: Add new {add,remove}_cpu() functions (diff)
downloadlinux-0441a5597c5d02ed7abed1d989eaaa1595dedac5.tar.xz
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cpu/hotplug: Create a new function to shutdown nonboot cpus
This function will be used later in machine_shutdown() for some architectures. disable_nonboot_cpus() is not safe to use when doing machine_down(), because it relies on freeze_secondary_cpus() which in turn is a suspend/resume related freeze and could abort if the logic detects any pending activities that can prevent finishing the offlining process. Signed-off-by: Qais Yousef <qais.yousef@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200323135110.30522-3-qais.yousef@arm.com
Diffstat (limited to 'kernel/cpu.c')
-rw-r--r--kernel/cpu.c42
1 files changed, 42 insertions, 0 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 069802f7010f..03c727195b65 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1069,6 +1069,48 @@ int remove_cpu(unsigned int cpu)
}
EXPORT_SYMBOL_GPL(remove_cpu);
+void smp_shutdown_nonboot_cpus(unsigned int primary_cpu)
+{
+ unsigned int cpu;
+ int error;
+
+ cpu_maps_update_begin();
+
+ /*
+ * Make certain the cpu I'm about to reboot on is online.
+ *
+ * This is inline to what migrate_to_reboot_cpu() already do.
+ */
+ if (!cpu_online(primary_cpu))
+ primary_cpu = cpumask_first(cpu_online_mask);
+
+ for_each_online_cpu(cpu) {
+ if (cpu == primary_cpu)
+ continue;
+
+ error = cpu_down_maps_locked(cpu, CPUHP_OFFLINE);
+ if (error) {
+ pr_err("Failed to offline CPU%d - error=%d",
+ cpu, error);
+ break;
+ }
+ }
+
+ /*
+ * Ensure all but the reboot CPU are offline.
+ */
+ BUG_ON(num_online_cpus() > 1);
+
+ /*
+ * Make sure the CPUs won't be enabled by someone else after this
+ * point. Kexec will reboot to a new kernel shortly resetting
+ * everything along the way.
+ */
+ cpu_hotplug_disabled++;
+
+ cpu_maps_update_done();
+}
+
#else
#define takedown_cpu NULL
#endif /*CONFIG_HOTPLUG_CPU*/