[PATCH 3.4 086/125] ARM: 8471/1: need to save/restore arm register(r11) when it is corrupted

[lizf]

From: Anson Huang 

3.4.113-rc1 review patch.  If anyone has any objections, please let me know.

--


commit fa0708b320f6da4c1104fe56e01b7abf66fd16ad upstream.

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 
Reviewed-by: Nicolas Pitre 
Signed-off-by: Russell King 
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li 
---
 arch/arm/mm/proc-v7.S | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index fb489cc..74c3e53 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -94,7 +94,7 @@ ENDPROC(cpu_v7_dcache_clean_area)
 .equ   cpu_v7_suspend_size, 4 * 8
 #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}
@@ -105,7 +105,7 @@ 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, {r6 - r11}
-   ldmfd   sp!, {r4 - r10, pc}
+   ldmfd   sp!, {r4 - r11, pc}
 ENDPROC(cpu_v7_do_suspend)
 
 ENTRY(cpu_v7_do_resume)
-- 
1.9.1

[PATCH 3.4 086/125] ARM: 8471/1: need to save/restore arm register(r11) when it is corrupted

[lizf]

From: Anson Huang 

3.4.113-rc1 review patch.  If anyone has any objections, please let me know.

--


commit fa0708b320f6da4c1104fe56e01b7abf66fd16ad upstream.

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 
Reviewed-by: Nicolas Pitre 
Signed-off-by: Russell King 
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li 
---
 arch/arm/mm/proc-v7.S | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index fb489cc..74c3e53 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -94,7 +94,7 @@ ENDPROC(cpu_v7_dcache_clean_area)
 .equ   cpu_v7_suspend_size, 4 * 8
 #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}
@@ -105,7 +105,7 @@ 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, {r6 - r11}
-   ldmfd   sp!, {r4 - r10, pc}
+   ldmfd   sp!, {r4 - r11, pc}
 ENDPROC(cpu_v7_do_suspend)
 
 ENTRY(cpu_v7_do_resume)
-- 
1.9.1