1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License.  See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (c) 1996, 1999 by Ralf Baechle
7 */
8#include <linux/errno.h>
9#include <asm/asm.h>
10#include <asm/asm-offsets.h>
11#include <asm/regdef.h>
12
13#define EX(insn,reg,addr,handler)			\
149:	insn	reg, addr;				\
15	.section __ex_table,"a";			\
16	PTR	9b, handler;				\
17	.previous
18
19/*
20 * Returns: -EFAULT if exception before terminator, N if the entire
21 * buffer filled, else strlen.
22 */
23
24/*
25 * Ugly special case have to check: we might get passed a user space
26 * pointer which wraps into the kernel space.  We don't deal with that.  If
27 * it happens at most some bytes of the exceptions handlers will be copied.
28 */
29
30LEAF(__strncpy_from_user_asm)
31	LONG_L		v0, TI_ADDR_LIMIT($28)	# pointer ok?
32	and		v0, a1
33	bnez		v0, .Lfault
34
35FEXPORT(__strncpy_from_user_nocheck_asm)
36	move		v0, zero
37	move		v1, a1
38	.set		noreorder
391:	EX(lbu, t0, (v1), .Lfault)
40	PTR_ADDIU	v1, 1
41	R10KCBARRIER(0(ra))
42	beqz		t0, 2f
43	 sb		t0, (a0)
44	PTR_ADDIU	v0, 1
45	.set		reorder
46	PTR_ADDIU	a0, 1
47	bne		v0, a2, 1b
482:	PTR_ADDU	t0, a1, v0
49	xor		t0, a1
50	bltz		t0, .Lfault
51	jr		ra			# return n
52	END(__strncpy_from_user_asm)
53
54.Lfault:	li		v0, -EFAULT
55	jr		ra
56
57	.section	__ex_table,"a"
58	PTR		1b, .Lfault
59	.previous
60