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, 1998, 1999, 2004 by Ralf Baechle
7 * Copyright (c) 1999 Silicon Graphics, Inc.
8 */
9#include <linux/export.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_WD	9b, handler;				\
18	.previous
19
20/*
21 * Return the size of a string including the ending NUL character up to a
22 * maximum of a1 or 0 in case of error.
23 *
24 * Note: for performance reasons we deliberately accept that a user may
25 *	 make strlen_user and strnlen_user access the first few KSEG0
26 *	 bytes.	 There's nothing secret there.	On 64-bit accessing beyond
27 *	 the maximum is a tad hairier ...
28 */
29LEAF(__strnlen_user_asm)
30	move		v0, a0
31	PTR_ADDU	a1, a0			# stop pointer
321:
33#ifdef CONFIG_CPU_DADDI_WORKAROUNDS
34	.set		noat
35	li		AT, 1
36#endif
37	beq		v0, a1, 1f		# limit reached?
38#ifdef CONFIG_EVA
39	.set push
40	.set eva
41	EX(lbe, t0, (v0), .Lfault)
42	.set pop
43#else
44	EX(lb, t0, (v0), .Lfault)
45#endif
46	.set		noreorder
47	bnez		t0, 1b
481:
49#ifndef CONFIG_CPU_DADDI_WORKAROUNDS
50	 PTR_ADDIU	v0, 1
51#else
52	 PTR_ADDU	v0, AT
53	.set		at
54#endif
55	.set		reorder
56	PTR_SUBU	v0, a0
57	jr		ra
58	END(__strnlen_user_asm)
59
60.Lfault:
61	move		v0, zero
62	jr		ra
63
64	EXPORT_SYMBOL(__strnlen_user_asm)
65