ARM: 7466/1: disable interrupt before spinning endlessly

commit 98bd8b96 upstream.

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 <shawn.guo@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

arch/arm/kernel/process.c

@@ -125,6 +125,7 @@ void arm_machine_restart(char mode, const char *cmd)
 	 */
 	mdelay(1000);
 	printk("Reboot failed -- System halted\n");
+	local_irq_disable();
 	while (1);
 }
 
@@ -240,6 +241,7 @@ void machine_shutdown(void)
 void machine_halt(void)
 {
 	machine_shutdown();
+	local_irq_disable();
 	while (1);
 }