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Diffstat (limited to 'arch/mips/lib/strnlen_user.S')
-rw-r--r-- | arch/mips/lib/strnlen_user.S | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/arch/mips/lib/strnlen_user.S b/arch/mips/lib/strnlen_user.S new file mode 100644 index 000000000000..6e7a8eed4de8 --- /dev/null +++ b/arch/mips/lib/strnlen_user.S | |||
@@ -0,0 +1,45 @@ | |||
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 <asm/asm.h> | ||
10 | #include <asm/offset.h> | ||
11 | #include <asm/regdef.h> | ||
12 | |||
13 | #define EX(insn,reg,addr,handler) \ | ||
14 | 9: insn reg, addr; \ | ||
15 | .section __ex_table,"a"; \ | ||
16 | PTR 9b, handler; \ | ||
17 | .previous | ||
18 | |||
19 | /* | ||
20 | * Return the size of a string including the ending NUL character upto a | ||
21 | * maximum of a1 or 0 in case of error. | ||
22 | * | ||
23 | * Note: for performance reasons we deliberately accept that a user may | ||
24 | * make strlen_user and strnlen_user access the first few KSEG0 | ||
25 | * bytes. There's nothing secret there. On 64-bit accessing beyond | ||
26 | * the maximum is a tad hairier ... | ||
27 | */ | ||
28 | LEAF(__strnlen_user_asm) | ||
29 | LONG_L v0, TI_ADDR_LIMIT($28) # pointer ok? | ||
30 | and v0, a0 | ||
31 | bnez v0, fault | ||
32 | |||
33 | FEXPORT(__strnlen_user_nocheck_asm) | ||
34 | move v0, a0 | ||
35 | PTR_ADDU a1, a0 # stop pointer | ||
36 | 1: beq v0, a1, 1f # limit reached? | ||
37 | EX(lb, t0, (v0), fault) | ||
38 | PTR_ADDU v0, 1 | ||
39 | bnez t0, 1b | ||
40 | 1: PTR_SUBU v0, a0 | ||
41 | jr ra | ||
42 | END(__strnlen_user_asm) | ||
43 | |||
44 | fault: move v0, zero | ||
45 | jr ra | ||