On 12/06/2012 09:05 PM, Steven J. Hill wrote:
From: "Steven J. Hill" <sjhill@xxxxxxxx> Optimise 'strncpy' to use microMIPS instructions and/or optimisations for binary size reduction. When the microMIPS ISA is not being used, the library function compiles to the original binary code.
This is an untrue statement. Why mislead us by saying the original binary code is obtained?
You don't really explain how the change helps optimization either.
Signed-off-by: Steven J. Hill <sjhill@xxxxxxxx> --- arch/mips/lib/strncpy_user.S | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-) diff --git a/arch/mips/lib/strncpy_user.S b/arch/mips/lib/strncpy_user.S index 7201b2f..dea9304 100644 --- a/arch/mips/lib/strncpy_user.S +++ b/arch/mips/lib/strncpy_user.S @@ -3,7 +3,8 @@ * License. See the file "COPYING" in the main directory of this archive * for more details. * - * Copyright (c) 1996, 1999 by Ralf Baechle + * Copyright (C) 1996, 1999 by Ralf Baechle + * Copyright (C) 2011 MIPS Technologies, Inc. */ #include <linux/errno.h> #include <asm/asm.h> @@ -33,22 +34,23 @@ LEAF(__strncpy_from_user_asm) bnez v0, .Lfault FEXPORT(__strncpy_from_user_nocheck_asm) - move v0, zero - move v1, a1 .set noreorder -1: EX(lbu, t0, (v1), .Lfault) + move t0, zero + move v1, a1 +1: EX(lbu, v0, (v1), .Lfault)
Look at these changes. v0 and t0 are not the same thing. the binary is being changed.
PTR_ADDIU v1, 1 R10KCBARRIER(0(ra)) - beqz t0, 2f - sb t0, (a0) - PTR_ADDIU v0, 1 - .set reorder - PTR_ADDIU a0, 1 - bne v0, a2, 1b -2: PTR_ADDU t0, a1, v0 - xor t0, a1 - bltz t0, .Lfault + beqz v0, 2f + sb v0, (a0) + PTR_ADDIU t0, 1 + bne t0, a2, 1b + PTR_ADDIU a0, 1 +2: PTR_ADDU v0, a1, t0 + xor v0, a1 + bltz v0, .Lfault + nop jr ra # return n + move v0, t0 END(__strncpy_from_user_asm) .Lfault: li v0, -EFAULT
