[PATCH] ARM: disable interrupt before spinning endlessly

The CPU will endlessly spin at the end of machine_halt and
machine_restart calls.  However, this will lead to a soft lockup
warning after about 20 seconds, if CONFIG_LOCKUP_DETECTOR is enabled,
as system timer is still alive.

Disable interrupt before going to spin endlessly, so that the lockup
warning will never be seen.

Reported-by: Marek Vasut <marex@denx.de>
Signed-off-by: Shawn Guo <redacted>
---
 arch/arm/kernel/process.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 19c95ea..693b744 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c

@@ -247,6 +247,7 @@ void machine_shutdown(void)
 void machine_halt(void)
 {
 	machine_shutdown();
+	local_irq_disable();
 	while (1);
 }
 

@@ -268,6 +269,7 @@ void machine_restart(char *cmd)
 
 	/* Whoops - the platform was unable to reboot. Tell the user! */
 	printk("Reboot failed -- System halted\n");
+	local_irq_disable();
 	while (1);
 }
 

-- 
1.7.5.4

Russell,

I took this patch as a trivial one and just put it into the patch
system as 7466/1, though I have got neither Reviewed-by nor Tested-by
with the patch on the list for several days.

Regards,
Shawn

On Mon, Jul 09, 2012 at 05:09:48PM +0800, Shawn Guo wrote:

Dear Shawn Guo,

The CPU will endlessly spin at the end of machine_halt and
machine_restart calls.  However, this will lead to a soft lockup
warning after about 20 seconds, if CONFIG_LOCKUP_DETECTOR is enabled,
as system timer is still alive.

Disable interrupt before going to spin endlessly, so that the lockup
warning will never be seen.

Reported-by: Marek Vasut <marex@denx.de>
Signed-off-by: Shawn Guo <redacted>
---
 arch/arm/kernel/process.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

I just got back from a conference, I'd gladly test. But my mx28 doesn't boot at 
all with latest -next. Any idea why?

Best regards,
Marek Vasut

On Mon, Jul 09, 2012 at 05:09:48PM +0800, Shawn Guo wrote:

The CPU will endlessly spin at the end of machine_halt and
machine_restart calls.  However, this will lead to a soft lockup
warning after about 20 seconds, if CONFIG_LOCKUP_DETECTOR is enabled,
as system timer is still alive.

Disable interrupt before going to spin endlessly, so that the lockup
warning will never be seen.

Reported-by: Marek Vasut <marex@denx.de>
Signed-off-by: Shawn Guo <redacted>
---

Should this also be Cc'd to stable when it's committed?

On Sun, Jul 29, 2012 at 10:22:16PM +0100, Russell King - ARM Linux wrote:

On Mon, Jul 09, 2012 at 05:09:48PM +0800, Shawn Guo wrote:

quoted

The CPU will endlessly spin at the end of machine_halt and
machine_restart calls.  However, this will lead to a soft lockup
warning after about 20 seconds, if CONFIG_LOCKUP_DETECTOR is enabled,
as system timer is still alive.

Disable interrupt before going to spin endlessly, so that the lockup
warning will never be seen.

Reported-by: Marek Vasut <marex@denx.de>
Signed-off-by: Shawn Guo <redacted>
---

Should this also be Cc'd to stable when it's committed?

Yes, I forgot it.

I assume you will take care of it when you commit it to your tree.
Otherwise, please let me know and I will resubmit the patch.

-- 
Regards,
Shawn