tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * linux/arch/arm/lib/strncpy_from_user.S
3 *
4 * Copyright (C) 1995-2000 Russell King
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10#include <linux/linkage.h>
11#include <asm/assembler.h>
12#include <asm/errno.h>
13
14 .text
15 .align 5
16
17/*
18 * Copy a string from user space to kernel space.
19 * r0 = dst, r1 = src, r2 = byte length
20 * returns the number of characters copied (strlen of copied string),
21 * -EFAULT on exception, or "len" if we fill the whole buffer
22 */
23ENTRY(__strncpy_from_user)
24 mov ip, r1
251: subs r2, r2, #1
26USER( ldrplbt r3, [r1], #1)
27 bmi 2f
28 strb r3, [r0], #1
29 teq r3, #0
30 bne 1b
31 sub r1, r1, #1 @ take NUL character out of count
322: sub r0, r1, ip
33 mov pc, lr
34
35 .section .fixup,"ax"
36 .align 0
379001: mov r3, #0
38 strb r3, [r0, #0] @ null terminate
39 mov r0, #-EFAULT
40 mov pc, lr
41 .previous
42