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 <asm/asm.h>
11#include <asm/asm-offsets.h>
12#include <asm/regdef.h>
13
14#define EX(insn,reg,addr,handler)			\
159:	insn	reg, addr;				\
16	.section __ex_table,"a";			\
17	PTR	9b, handler;				\
18	.previous
19
20/*
21 * Returns: -EFAULT if exception before terminator, N if the entire
22 * buffer filled, else strlen.
23 */
24
25/*
26 * Ugly special case have to check: we might get passed a user space
27 * pointer which wraps into the kernel space.  We don't deal with that.	 If
28 * it happens at most some bytes of the exceptions handlers will be copied.
29 */
30
31	.macro __BUILD_STRNCPY_ASM func
32LEAF(__strncpy_from_\func\()_asm)
33	LONG_L		v0, TI_ADDR_LIMIT($28)	# pointer ok?
34	and		v0, a1
35	bnez		v0, .Lfault\@
36
37FEXPORT(__strncpy_from_\func\()_nocheck_asm)
38	move		t0, zero
39	move		v1, a1
40.ifeqs "\func","kernel"
411:	EX(lbu, v0, (v1), .Lfault\@)
42.else
431:	EX(lbue, v0, (v1), .Lfault\@)
44.endif
45	PTR_ADDIU	v1, 1
46	R10KCBARRIER(0(ra))
47	sb		v0, (a0)
48	beqz		v0, 2f
49	PTR_ADDIU	t0, 1
50	PTR_ADDIU	a0, 1
51	bne		t0, a2, 1b
522:	PTR_ADDU	v0, a1, t0
53	xor		v0, a1
54	bltz		v0, .Lfault\@
55	move		v0, t0
56	jr		ra			# return n
57	END(__strncpy_from_\func\()_asm)
58
59.Lfault\@:
60	li		v0, -EFAULT
61	jr		ra
62
63	.section	__ex_table,"a"
64	PTR		1b, .Lfault\@
65	.previous
66
67	.endm
68
69#ifndef CONFIG_EVA
70	/* Set aliases */
71	.global __strncpy_from_user_asm
72	.global __strncpy_from_user_nocheck_asm
73	.set __strncpy_from_user_asm, __strncpy_from_kernel_asm
74	.set __strncpy_from_user_nocheck_asm, __strncpy_from_kernel_nocheck_asm
75#endif
76
77__BUILD_STRNCPY_ASM kernel
78
79#ifdef CONFIG_EVA
80	.set push
81	.set eva
82__BUILD_STRNCPY_ASM user
83	.set pop
84#endif
85