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 * Copyright (C) 2011 MIPS Technologies, Inc.
8 */
9#include <linux/errno.h>
10#include <linux/export.h>
11#include <asm/asm.h>
12#include <asm/asm-offsets.h>
13#include <asm/regdef.h>
14
15#define EX(insn,reg,addr,handler)			\
169:	insn	reg, addr;				\
17	.section __ex_table,"a";			\
18	PTR_WD	9b, handler;				\
19	.previous
20
21/*
22 * Returns: -EFAULT if exception before terminator, N if the entire
23 * buffer filled, else strlen.
24 */
25
26/*
27 * Ugly special case have to check: we might get passed a user space
28 * pointer which wraps into the kernel space.  We don't deal with that.	 If
29 * it happens at most some bytes of the exceptions handlers will be copied.
30 */
31
32LEAF(__strncpy_from_user_asm)
33	move		t0, zero
34	move		v1, a1
35#ifdef CONFIG_EVA
36	.set push
37	.set eva
381:	EX(lbue, v0, (v1), .Lfault)
39	.set pop
40#else
411:	EX(lbu, v0, (v1), .Lfault)
42#endif
43	PTR_ADDIU	v1, 1
44	R10KCBARRIER(0(ra))
45	sb		v0, (a0)
46	beqz		v0, 2f
47	PTR_ADDIU	t0, 1
48	PTR_ADDIU	a0, 1
49	bne		t0, a2, 1b
502:	PTR_ADDU	v0, a1, t0
51	xor		v0, a1
52	bltz		v0, .Lfault
53	move		v0, t0
54	jr		ra			# return n
55	END(__strncpy_from_user_asm)
56
57.Lfault:
58	li		v0, -EFAULT
59	jr		ra
60
61	.section	__ex_table,"a"
62	PTR_WD		1b, .Lfault
63	.previous
64
65	EXPORT_SYMBOL(__strncpy_from_user_asm)
66