| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 |