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* [PATCH] ARM: Use the correct NOP size in memmove for Thumb-2 kernel builds
@ 2010-03-26 11:11 Catalin Marinas
  2010-03-28 21:52 ` Russell King - ARM Linux
  0 siblings, 1 reply; 2+ messages in thread
From: Catalin Marinas @ 2010-03-26 11:11 UTC (permalink / raw)
  To: linux-arm-kernel

When compiling the kernel to Thumb-2, using a 16-bit NOP in the
memmove() implementation causes the preceding ADD PC instruction to
branch incorrectly in the middle of a 32-bit LDR or STR instruction. The
memmove() code is no similar to the memcpy() template.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
 arch/arm/lib/memmove.S |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/lib/memmove.S b/arch/arm/lib/memmove.S
index 5025c86..938fc14 100644
--- a/arch/arm/lib/memmove.S
+++ b/arch/arm/lib/memmove.S
@@ -74,7 +74,7 @@ ENTRY(memmove)
 		rsb	ip, ip, #32
 		addne	pc, pc, ip		@ C is always clear here
 		b	7f
-6:		nop
+6:		W(nop)
 		W(ldr)	r3, [r1, #-4]!
 		W(ldr)	r4, [r1, #-4]!
 		W(ldr)	r5, [r1, #-4]!
@@ -85,7 +85,7 @@ ENTRY(memmove)
 
 		add	pc, pc, ip
 		nop
-		nop
+		W(nop)
 		W(str)	r3, [r0, #-4]!
 		W(str)	r4, [r0, #-4]!
 		W(str)	r5, [r0, #-4]!

^ permalink raw reply related	[flat|nested] 2+ messages in thread

* [PATCH] ARM: Use the correct NOP size in memmove for Thumb-2 kernel builds
  2010-03-26 11:11 [PATCH] ARM: Use the correct NOP size in memmove for Thumb-2 kernel builds Catalin Marinas
@ 2010-03-28 21:52 ` Russell King - ARM Linux
  0 siblings, 0 replies; 2+ messages in thread
From: Russell King - ARM Linux @ 2010-03-28 21:52 UTC (permalink / raw)
  To: linux-arm-kernel

On Fri, Mar 26, 2010 at 11:11:22AM +0000, Catalin Marinas wrote:
> When compiling the kernel to Thumb-2, using a 16-bit NOP in the
> memmove() implementation causes the preceding ADD PC instruction to
> branch incorrectly in the middle of a 32-bit LDR or STR instruction. The
> memmove() code is no similar to the memcpy() template.

Ok.

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2010-03-26 11:11 [PATCH] ARM: Use the correct NOP size in memmove for Thumb-2 kernel builds Catalin Marinas
2010-03-28 21:52 ` Russell King - ARM Linux

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