1/* 2 * linux/arch/arm/lib/getuser.S 3 * 4 * Copyright (C) 2001 Russell King 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 * Idea from x86 version, (C) Copyright 1998 Linus Torvalds 11 * 12 * These functions have a non-standard call interface to make them more 13 * efficient, especially as they return an error value in addition to 14 * the "real" return value. 15 * 16 * __get_user_X 17 * 18 * Inputs: r0 contains the address 19 * Outputs: r0 is the error code 20 * r2, r3 contains the zero-extended value 21 * lr corrupted 22 * 23 * No other registers must be altered. (see <asm/uaccess.h> 24 * for specific ASM register usage). 25 * 26 * Note that ADDR_LIMIT is either 0 or 0xc0000000. 27 * Note also that it is intended that __get_user_bad is not global. 28 */ 29#include <asm/errno.h> 30 31 .global __get_user_1 32__get_user_1: 331: ldrbt r2, [r0] 34 mov r0, #0 35 mov pc, lr 36 37 .global __get_user_2 38__get_user_2: 392: ldrbt r2, [r0], #1 403: ldrbt r3, [r0] 41#ifndef __ARMEB__ 42 orr r2, r2, r3, lsl #8 43#else 44 orr r2, r3, r2, lsl #8 45#endif 46 mov r0, #0 47 mov pc, lr 48 49 .global __get_user_4 50__get_user_4: 514: ldrt r2, [r0] 52 mov r0, #0 53 mov pc, lr 54 55__get_user_bad: 56 mov r2, #0 57 mov r0, #-EFAULT 58 mov pc, lr 59 60.section __ex_table, "a" 61 .long 1b, __get_user_bad 62 .long 2b, __get_user_bad 63 .long 3b, __get_user_bad 64 .long 4b, __get_user_bad 65.previous 66