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 <linux/linkage.h> 30#include <asm/errno.h> 31#include <asm/domain.h> 32 33ENTRY(__get_user_1) 341: TUSER(ldrb) r2, [r0] 35 mov r0, #0 36 mov pc, lr 37ENDPROC(__get_user_1) 38 39ENTRY(__get_user_2) 40#ifdef CONFIG_THUMB2_KERNEL 412: TUSER(ldrb) r2, [r0] 423: TUSER(ldrb) r3, [r0, #1] 43#else 442: TUSER(ldrb) r2, [r0], #1 453: TUSER(ldrb) r3, [r0] 46#endif 47#ifndef __ARMEB__ 48 orr r2, r2, r3, lsl #8 49#else 50 orr r2, r3, r2, lsl #8 51#endif 52 mov r0, #0 53 mov pc, lr 54ENDPROC(__get_user_2) 55 56ENTRY(__get_user_4) 574: TUSER(ldr) r2, [r0] 58 mov r0, #0 59 mov pc, lr 60ENDPROC(__get_user_4) 61 62__get_user_bad: 63 mov r2, #0 64 mov r0, #-EFAULT 65 mov pc, lr 66ENDPROC(__get_user_bad) 67 68.pushsection __ex_table, "a" 69 .long 1b, __get_user_bad 70 .long 2b, __get_user_bad 71 .long 3b, __get_user_bad 72 .long 4b, __get_user_bad 73.popsection 74