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/asm-offsets.h> 11#include <asm/regdef.h> 12 13#define EX(insn,reg,addr,handler) \ 149: 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 up to 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 */ 28LEAF(__strnlen_user_asm) 29 LONG_L v0, TI_ADDR_LIMIT($28) # pointer ok? 30 and v0, a0 31 bnez v0, .Lfault 32 33FEXPORT(__strnlen_user_nocheck_asm) 34 move v0, a0 35 PTR_ADDU a1, a0 # stop pointer 361: beq v0, a1, 1f # limit reached? 37 EX(lb, t0, (v0), .Lfault) 38 PTR_ADDIU v0, 1 39 bnez t0, 1b 401: PTR_SUBU v0, a0 41 jr ra 42 END(__strnlen_user_asm) 43 44.Lfault: 45 move v0, zero 46 jr ra 47