linux/arch/arm/lib/memcpy.S
Russell King 1bd46782d0 ARM: avoid unwanted GCC memset()/memcpy() optimisations for IO variants
We don't want GCC optimising our memset_io(), memcpy_fromio() or
memcpy_toio() variants, so we must not call one of the standard
functions.  Provide a separate name for our assembly memcpy() and
memset() functions, and use that instead, thereby bypassing GCC's
ability to optimise these operations.

GCCs optimisation may introduce unaligned accesses which are invalid
for device mappings.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-07-03 20:46:15 +01:00

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1.4 KiB
ArmAsm

/*
* linux/arch/arm/lib/memcpy.S
*
* Author: Nicolas Pitre
* Created: Sep 28, 2005
* Copyright: MontaVista Software, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/unwind.h>
#define LDR1W_SHIFT 0
#define STR1W_SHIFT 0
.macro ldr1w ptr reg abort
W(ldr) \reg, [\ptr], #4
.endm
.macro ldr4w ptr reg1 reg2 reg3 reg4 abort
ldmia \ptr!, {\reg1, \reg2, \reg3, \reg4}
.endm
.macro ldr8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
ldmia \ptr!, {\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8}
.endm
.macro ldr1b ptr reg cond=al abort
ldr\cond\()b \reg, [\ptr], #1
.endm
.macro str1w ptr reg abort
W(str) \reg, [\ptr], #4
.endm
.macro str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
stmia \ptr!, {\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8}
.endm
.macro str1b ptr reg cond=al abort
str\cond\()b \reg, [\ptr], #1
.endm
.macro enter reg1 reg2
stmdb sp!, {r0, \reg1, \reg2}
.endm
.macro usave reg1 reg2
UNWIND( .save {r0, \reg1, \reg2} )
.endm
.macro exit reg1 reg2
ldmfd sp!, {r0, \reg1, \reg2}
.endm
.text
/* Prototype: void *memcpy(void *dest, const void *src, size_t n); */
ENTRY(mmiocpy)
ENTRY(memcpy)
#include "copy_template.S"
ENDPROC(memcpy)
ENDPROC(mmiocpy)