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

From	lizf@kernel.org
Newsgroups	linux.kernel
Subject	[PATCH 3.4 086/125] ARM: 8471/1: need to save/restore arm register(r11) when it is corrupted
Date	2016-10-12 14:50 +0200
Message-ID	<srr8S-4rr-11@gated-at.bofh.it> (permalink)
References	<srqZb-4nM-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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From: Anson Huang <Anson.Huang@freescale.com>

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 <Anson.Huang@freescale.com>
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>
---
 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

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[PATCH 3.4 086/125] ARM: 8471/1: need to save/restore arm register(r11) when it is corrupted lizf@kernel.org - 2016-10-12 14:50 +0200

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