diff options
| author | Will Deacon <will.deacon@arm.com> | 2012-07-06 15:45:39 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2012-07-09 17:41:11 +0100 |
| commit | 8c56cc8be5b38e3684eba96dc9b3f7ca7e495755 (patch) | |
| tree | eccb882c8c5f1cc81fc226c769fc9ec99a45145b /arch/arm/lib/strncpy_from_user.S | |
| parent | 4295b898f5a5c7e62ae68e7a4ecc4b414622ffe6 (diff) | |
ARM: 7449/1: use generic strnlen_user and strncpy_from_user functions
This patch implements the word-at-a-time interface for ARM using the
same algorithm as x86. We use the fls macro from ARMv5 onwards, where
we have a clz instruction available which saves us a mov instruction
when targetting Thumb-2. For older CPUs, we use the magic 0x0ff0001
constant. Big-endian configurations make use of the implementation from
asm-generic.
With this implemented, we can replace our byte-at-a-time strnlen_user
and strncpy_from_user functions with the optimised generic versions.
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/lib/strncpy_from_user.S')
| -rw-r--r-- | arch/arm/lib/strncpy_from_user.S | 43 |
1 files changed, 0 insertions, 43 deletions
diff --git a/arch/arm/lib/strncpy_from_user.S b/arch/arm/lib/strncpy_from_user.S deleted file mode 100644 index f202d7bd164..00000000000 --- a/arch/arm/lib/strncpy_from_user.S +++ /dev/null @@ -1,43 +0,0 @@ -/* - * linux/arch/arm/lib/strncpy_from_user.S - * - * Copyright (C) 1995-2000 Russell King - * - * 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/errno.h> - - .text - .align 5 - -/* - * Copy a string from user space to kernel space. - * r0 = dst, r1 = src, r2 = byte length - * returns the number of characters copied (strlen of copied string), - * -EFAULT on exception, or "len" if we fill the whole buffer - */ -ENTRY(__strncpy_from_user) - mov ip, r1 -1: subs r2, r2, #1 - ldrusr r3, r1, 1, pl - bmi 2f - strb r3, [r0], #1 - teq r3, #0 - bne 1b - sub r1, r1, #1 @ take NUL character out of count -2: sub r0, r1, ip - mov pc, lr -ENDPROC(__strncpy_from_user) - - .pushsection .fixup,"ax" - .align 0 -9001: mov r3, #0 - strb r3, [r0, #0] @ null terminate - mov r0, #-EFAULT - mov pc, lr - .popsection - |