ARM: 8471/1: need to save/restore arm register(r11) when it is corrupted

In cpu_v7_do_suspend routine, r11 is used while it is NOT
saved/restored, different compiler may have different usage
of ARM general registers, so it may cause issues during
calling cpu_v7_do_suspend.

We meet kernel fault occurs when using GCC 4.8.3, r11 contains
valid value before calling into cpu_v7_do_suspend, but when returned
from this routine, r11 is corrupted and lead to kernel fault.
Doing save/restore for those corrupted registers is a must in
assemble code.

Signed-off-by: Anson Huang <Anson.Huang@freescale.com>
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Cc: <stable@vger.kernel.org> # v3.3+
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index de2b246..8e1ea43 100644 (file)
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -95,7 +95,7 @@ ENDPROC(cpu_v7_dcache_clean_area)
 .equ   cpu_v7_suspend_size, 4 * 9
 #ifdef CONFIG_ARM_CPU_SUSPEND
 ENTRY(cpu_v7_do_suspend)
-       stmfd   sp!, {r4 - r10, lr}
+       stmfd   sp!, {r4 - r11, lr}
        mrc     p15, 0, r4, c13, c0, 0  @ FCSE/PID
        mrc     p15, 0, r5, c13, c0, 3  @ User r/o thread ID
        stmia   r0!, {r4 - r5}
@@ -112,7 +112,7 @@ ENTRY(cpu_v7_do_suspend)
        mrc     p15, 0, r9, c1, c0, 1   @ Auxiliary control register
        mrc     p15, 0, r10, c1, c0, 2  @ Co-processor access control
        stmia   r0, {r5 - r11}
-       ldmfd   sp!, {r4 - r10, pc}
+       ldmfd   sp!, {r4 - r11, pc}
 ENDPROC(cpu_v7_do_suspend)
 
 ENTRY(cpu_v7_do_resume)