[PATCH 49/72] PM / reboot: call syscore_shutdown() after disable_nonboot_cpus()

Luis Henriques luis.henriques at canonical.com
Thu Apr 18 09:16:34 UTC 2013 -stable review patch.  If anyone has any objections, please let me know.


From: Huacai Chen <chenhc at lemote.com>

commit 6f389a8f1dd22a24f3d9afc2812b30d639e94625 upstream.

As commit 40dc166c (PM / Core: Introduce struct syscore_ops for core
subsystems PM) say, syscore_ops operations should be carried with one
CPU on-line and interrupts disabled. However, after commit f96972f2d
(kernel/sys.c: call disable_nonboot_cpus() in kernel_restart()),
syscore_shutdown() is called before disable_nonboot_cpus(), so break
the rules. We have a MIPS machine with a 8259A PIC, and there is an
external timer (HPET) linked at 8259A. Since 8259A has been shutdown
too early (by syscore_shutdown()), disable_nonboot_cpus() runs without
timer interrupt, so it hangs and reboot fails. This patch call
syscore_shutdown() a little later (after disable_nonboot_cpus()) to
avoid reboot failure, this is the same way as poweroff does.

For consistency, add disable_nonboot_cpus() to kernel_halt().

Signed-off-by: Huacai Chen <chenhc at lemote.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
 kernel/sys.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/sys.c b/kernel/sys.c
index b6fe559..0836a7f 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -323,7 +323,6 @@ void kernel_restart_prepare(char *cmd)
 	system_state = SYSTEM_RESTART;
-	syscore_shutdown();
@@ -369,6 +368,7 @@ void kernel_restart(char *cmd)
+	syscore_shutdown();
 	if (!cmd)
 		printk(KERN_EMERG "Restarting system.\n");
@@ -394,6 +394,7 @@ static void kernel_shutdown_prepare(enum system_states state)
 void kernel_halt(void)
+	disable_nonboot_cpus();
 	printk(KERN_EMERG "System halted.\n");

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