[PATCH] ARM: proc-v7: Ensure correct instruction set after cpu_reset

Dave Martin dave.martin at linaro.org
Wed Oct 3 05:22:50 EDT 2012

Because mov pc,<Rn> never switches instruction set when executed in
Thumb code, Thumb-2 kernels will silently execute the target code
after cpu_reset as Thumb code, even if the passed code pointer
denotes ARM (bit 0 clear).

This patch uses bx instead, ensuring the correct instruction set
for the target code.

Thumb code in the kernel is not supported prior to ARMv7, so other
CPUs are not affected.

Signed-off-by: Dave Martin <dave.martin at linaro.org>
 arch/arm/mm/proc-v7.S |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index c2e2b66..ca5b575 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -57,7 +57,7 @@ ENTRY(cpu_v7_reset)
  THUMB(	bic	r1, r1, #1 << 30 )		@ SCTLR.TE (Thumb exceptions)
 	mcr	p15, 0, r1, c1, c0, 0		@ disable MMU
-	mov	pc, r0
+	bx	r0

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