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- From 418df63adac56841ef6b0f1fcf435bc64d4ed177 Mon Sep 17 00:00:00 2001
- From: Nicolas Pitre <nicolas.pitre@linaro.org>
- Date: Tue, 12 Mar 2013 13:00:42 +0100
- Subject: [PATCH] ARM: 7670/1: fix the memset fix
- Commit 455bd4c430b0 ("ARM: 7668/1: fix memset-related crashes caused by
- recent GCC (4.7.2) optimizations") attempted to fix a compliance issue
- with the memset return value. However the memset itself became broken
- by that patch for misaligned pointers.
- This fixes the above by branching over the entry code from the
- misaligned fixup code to avoid reloading the original pointer.
- Also, because the function entry alignment is wrong in the Thumb mode
- compilation, that fixup code is moved to the end.
- While at it, the entry instructions are slightly reworked to help dual
- issue pipelines.
- Signed-off-by: Nicolas Pitre <nico@linaro.org>
- Tested-by: Alexander Holler <holler@ahsoftware.de>
- Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
- ---
- arch/arm/lib/memset.S | 33 +++++++++++++--------------------
- 1 file changed, 13 insertions(+), 20 deletions(-)
- --- a/arch/arm/lib/memset.S
- +++ b/arch/arm/lib/memset.S
- @@ -14,31 +14,15 @@
-
- .text
- .align 5
- - .word 0
- -
- -1: subs r2, r2, #4 @ 1 do we have enough
- - blt 5f @ 1 bytes to align with?
- - cmp r3, #2 @ 1
- - strltb r1, [ip], #1 @ 1
- - strleb r1, [ip], #1 @ 1
- - strb r1, [ip], #1 @ 1
- - add r2, r2, r3 @ 1 (r2 = r2 - (4 - r3))
- -/*
- - * The pointer is now aligned and the length is adjusted. Try doing the
- - * memset again.
- - */
-
- ENTRY(memset)
- -/*
- - * Preserve the contents of r0 for the return value.
- - */
- - mov ip, r0
- - ands r3, ip, #3 @ 1 unaligned?
- - bne 1b @ 1
- + ands r3, r0, #3 @ 1 unaligned?
- + mov ip, r0 @ preserve r0 as return value
- + bne 6f @ 1
- /*
- * we know that the pointer in ip is aligned to a word boundary.
- */
- - orr r1, r1, r1, lsl #8
- +1: orr r1, r1, r1, lsl #8
- orr r1, r1, r1, lsl #16
- mov r3, r1
- cmp r2, #16
- @@ -127,4 +111,13 @@ ENTRY(memset)
- tst r2, #1
- strneb r1, [ip], #1
- mov pc, lr
- +
- +6: subs r2, r2, #4 @ 1 do we have enough
- + blt 5b @ 1 bytes to align with?
- + cmp r3, #2 @ 1
- + strltb r1, [ip], #1 @ 1
- + strleb r1, [ip], #1 @ 1
- + strb r1, [ip], #1 @ 1
- + add r2, r2, r3 @ 1 (r2 = r2 - (4 - r3))
- + b 1b
- ENDPROC(memset)
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