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, 1999 by Ralf Baechle 7 * Copyright (C) 2011 MIPS Technologies, Inc. 8 */ 9#include <linux/errno.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 9b, handler; \ 18 .previous 19 20/* 21 * Returns: -EFAULT if exception before terminator, N if the entire 22 * buffer filled, else strlen. 23 */ 24 25/* 26 * Ugly special case have to check: we might get passed a user space 27 * pointer which wraps into the kernel space. We don't deal with that. If 28 * it happens at most some bytes of the exceptions handlers will be copied. 29 */ 30 31LEAF(__strncpy_from_user_asm) 32 LONG_L v0, TI_ADDR_LIMIT($28) # pointer ok? 33 and v0, a1 34 bnez v0, .Lfault 35 36FEXPORT(__strncpy_from_user_nocheck_asm) 37 .set noreorder 38 move t0, zero 39 move v1, a1 401: EX(lbu, v0, (v1), .Lfault) 41 PTR_ADDIU v1, 1 42 R10KCBARRIER(0(ra)) 43 beqz v0, 2f 44 sb v0, (a0) 45 PTR_ADDIU t0, 1 46 bne t0, a2, 1b 47 PTR_ADDIU a0, 1 482: PTR_ADDU v0, a1, t0 49 xor v0, a1 50 bltz v0, .Lfault 51 nop 52 jr ra # return n 53 move v0, t0 54 END(__strncpy_from_user_asm) 55 56.Lfault: jr ra 57 li v0, -EFAULT 58 59 .section __ex_table,"a" 60 PTR 1b, .Lfault 61 .previous 62