PM / reboot: call syscore_shutdown() after disable_nonboot_cpus()

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@lemote.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/kernel/sys.c b/kernel/sys.c
index 39c9c4a2949f..0da73cf73e60 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -324,7 +324,6 @@ void kernel_restart_prepare(char *cmd)
         system_state = SYSTEM_RESTART;
         usermodehelper_disable();
         device_shutdown();
-        syscore_shutdown();
 }
 
 /**
@@ -370,6 +369,7 @@ void kernel_restart(char *cmd)
 {
         kernel_restart_prepare(cmd);
         disable_nonboot_cpus();
+        syscore_shutdown();
         if (!cmd)
                 printk(KERN_EMERG "Restarting system.\n");
         else
@@ -395,6 +395,7 @@ static void kernel_shutdown_prepare(enum system_states state)
 void kernel_halt(void)
 {
         kernel_shutdown_prepare(SYSTEM_HALT);
+        disable_nonboot_cpus();
         syscore_shutdown();
         printk(KERN_EMERG "System halted.\n");
         kmsg_dump(KMSG_DUMP_HALT);