diff options
Diffstat (limited to 'arch/arm/lib/strncpy_from_user.S')
| -rw-r--r-- | arch/arm/lib/strncpy_from_user.S | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/arch/arm/lib/strncpy_from_user.S b/arch/arm/lib/strncpy_from_user.S new file mode 100644 index 00000000000..629cc877527 --- /dev/null +++ b/arch/arm/lib/strncpy_from_user.S @@ -0,0 +1,43 @@ +/* + * 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(__arch_strncpy_from_user) + save_lr + mov ip, r1 +1: subs r2, r2, #1 +USER( ldrplbt r3, [r1], #1) + 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 + restore_pc + + .section .fixup,"ax" + .align 0 +9001: mov r3, #0 + strb r3, [r0, #0] @ null terminate + mov r0, #-EFAULT + restore_pc + .previous + |