Commit fa0708b3 authored Dec 07, 2015 by Anson Huang Committed by Russell King Dec 15, 2015

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>

parent c014953d

arch/arm/mm/proc-v7.S

+2 −2

Original line number	Diff line number	Diff line
		@@ -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)

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