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ARM: 7066/1: proc-v7: disable SCTLR.TE when disabling MMU

cpu_v7_reset disables the MMU and then branches to the provided address.
On Thumb-2 kernels, we should take care to clear the Thumb Exception
enable bit in the System Control Register, otherwise this may wreak
havok in the code to which we are branching (for example, an ARM kernel
image via kexec).

Reviewed-by: Dave Martin <dave.martin@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Will Deacon 14 жил өмнө
parent
commit
0f81bb6b05

+ 1 - 0
arch/arm/mm/proc-v7.S

@@ -66,6 +66,7 @@ ENDPROC(cpu_v7_proc_fin)
 ENTRY(cpu_v7_reset)
 ENTRY(cpu_v7_reset)
 	mrc	p15, 0, r1, c1, c0, 0		@ ctrl register
 	mrc	p15, 0, r1, c1, c0, 0		@ ctrl register
 	bic	r1, r1, #0x1			@ ...............m
 	bic	r1, r1, #0x1			@ ...............m
+ THUMB(	bic	r1, r1, #1 << 30 )		@ SCTLR.TE (Thumb exceptions)
 	mcr	p15, 0, r1, c1, c0, 0		@ disable MMU
 	mcr	p15, 0, r1, c1, c0, 0		@ disable MMU
 	isb
 	isb
 	mov	pc, r0
 	mov	pc, r0