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arm64: klib: Optimised string functions

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This patch introduces AArch64-specific string functions (strchr,
strrchr).

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Catalin Marinas 2013-03-21 16:23:43 +00:00
parent 4a8992271c
commit 2b8cac814c
5 changed files with 95 additions and 1 deletions
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6
arch/arm64/include/asm/string.h
View file

@ -16,6 +16,12 @@
#ifndef __ASM_STRING_H
#define __ASM_STRING_H
#define __HAVE_ARCH_STRRCHR
extern char *strrchr(const char *, int c);
#define __HAVE_ARCH_STRCHR
extern char *strchr(const char *, int c);
#define __HAVE_ARCH_MEMCPY
extern void *memcpy(void *, const void *, __kernel_size_t);

2
arch/arm64/kernel/arm64ksyms.c
View file

@ -48,6 +48,8 @@ EXPORT_SYMBOL(__atomic_hash);
EXPORT_SYMBOL(memstart_addr);
/* string / mem functions */
EXPORT_SYMBOL(strchr);
EXPORT_SYMBOL(strrchr);
EXPORT_SYMBOL(memset);
EXPORT_SYMBOL(memcpy);
EXPORT_SYMBOL(memmove);

3
arch/arm64/lib/Makefile
View file

@ -2,4 +2,5 @@ lib-y := bitops.o delay.o \
strncpy_from_user.o strnlen_user.o clear_user.o \
copy_from_user.o copy_to_user.o copy_in_user.o \
copy_page.o clear_page.o \
memchr.o memcpy.o memmove.o memset.o
memchr.o memcpy.o memmove.o memset.o \
strchr.o strrchr.o

42
arch/arm64/lib/strchr.S Normal file
View file

@ -0,0 +1,42 @@
/*
* Based on arch/arm/lib/strchr.S
*
* Copyright (C) 1995-2000 Russell King
* Copyright (C) 2013 ARM Ltd.
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
/*
* Find the first occurrence of a character in a string.
*
* Parameters:
* x0 - str
* x1 - c
* Returns:
* x0 - address of first occurrence of 'c' or 0
*/
ENTRY(strchr)
and w1, w1, #0xff
1: ldrb w2, [x0], #1
cmp w2, w1
ccmp w2, wzr, #4, ne
b.ne 1b
sub x0, x0, #1
cmp w2, w1
csel x0, x0, xzr, eq
ret
ENDPROC(strchr)

43
arch/arm64/lib/strrchr.S Normal file
View file

@ -0,0 +1,43 @@
/*
* Based on arch/arm/lib/strrchr.S
*
* Copyright (C) 1995-2000 Russell King
* Copyright (C) 2013 ARM Ltd.
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
/*
* Find the last occurrence of a character in a string.
*
* Parameters:
* x0 - str
* x1 - c
* Returns:
* x0 - address of last occurrence of 'c' or 0
*/
ENTRY(strrchr)
mov x3, #0
and w1, w1, #0xff
1: ldrb w2, [x0], #1
cbz w2, 2f
cmp w2, w1
b.ne 1b
sub x3, x0, #1
b 1b
2: mov x0, x3
ret
ENDPROC(strrchr)