Patch "ARM: 8471/1: need to save/restore arm register(r11) when it is corrupted" has been added to the 3.14-stable tree

This is a note to let you know that I've just added the patch titled

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

to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:

     arm-8471-1-need-to-save-restore-arm-register-r11-when-it-is-corrupted.patch

and it can be found in the queue-3.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Anson Huang <[email protected]>
Date: Mon, 7 Dec 2015 10:09:19 +0100
Subject: ARM: 8471/1: need to save/restore arm register(r11) when it is corrupted

From: Anson Huang <[email protected]>

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.

---
 arch/arm/mm/proc-v7.S |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

@@ -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)

Patches currently in stable-queue which might be from [email protected] are

queue-3.14/arm-8471-1-need-to-save-restore-arm-register-r11-when-it-is-corrupted.patch