From 4586f9626b851a312eae3e452e2be5a5a2cf585d Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Tue, 12 Mar 2013 13:00:42 +0100 Subject: ARM: fix the memset fix From Kernel commit 418df63a 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 | Tested-by: Alexander Holler | Signed-off-by: Russell King Signed-off-by: Sascha Hauer --- arch/arm/lib/memset.S | 33 +++++++++++++-------------------- 1 file changed, 13 insertions(+), 20 deletions(-) diff --git a/arch/arm/lib/memset.S b/arch/arm/lib/memset.S index 5e35d7f5f6..c4d2672038 100644 --- 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 @@ -127,5 +111,14 @@ 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) -- cgit v1.2.3