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 * Copyright (C) 2011 MIPS Technologies, Inc. 9 */ 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 * Return the size of a string including the ending NUL character upto 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 .set noreorder 31 LONG_L v0, TI_ADDR_LIMIT($28) # pointer ok? 32 and v0, a0 33#ifdef CONFIG_CPU_MICROMIPS 34 bnezc v0, .Lfault 35#else 36 bnez v0, .Lfault 37#endif 38 39FEXPORT(__strnlen_user_nocheck_asm) 40 PTR_ADDU a1, a0 # stop pointer 41 move v0, a0 421: beq v0, a1, 1f # limit reached? 43 nop 44 EX(lb, t0, (v0), .Lfault) 45#ifdef CONFIG_CPU_MICROMIPS 46 addius5 v0, 1 47 bnezc t0, 1b 481: jr ra 49 PTR_SUBU v0, a0 50#else 51 bnez t0, 1b 52 PTR_ADDU v0, 1 53 jr ra 541: PTR_SUBU v0, a0 55#endif 56 END(__strnlen_user_asm) 57 58.Lfault: 59 jr ra 60 move v0, zero 61