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 * r1 contains the address limit, which must be preserved 20 * Outputs: r0 is the error code 21 * r2 contains the zero-extended value 22 * lr corrupted 23 * 24 * No other registers must be altered. (see <asm/uaccess.h> 25 * for specific ASM register usage). 26 * 27 * Note that ADDR_LIMIT is either 0 or 0xc0000000. 28 * Note also that it is intended that __get_user_bad is not global. 29 */ 30#include <linux/linkage.h> 31#include <asm/assembler.h> 32#include <asm/errno.h> 33#include <asm/domain.h> 34 35ENTRY(__get_user_1) 36 check_uaccess r0, 1, r1, r2, __get_user_bad 371: TUSER(ldrb) r2, [r0] 38 mov r0, #0 39 mov pc, lr 40ENDPROC(__get_user_1) 41 42ENTRY(__get_user_2) 43 check_uaccess r0, 2, r1, r2, __get_user_bad 44#ifdef CONFIG_CPU_USE_DOMAINS 45rb .req ip 462: ldrbt r2, [r0], #1 473: ldrbt rb, [r0], #0 48#else 49rb .req r0 502: ldrb r2, [r0] 513: ldrb rb, [r0, #1] 52#endif 53#ifndef __ARMEB__ 54 orr r2, r2, rb, lsl #8 55#else 56 orr r2, rb, r2, lsl #8 57#endif 58 mov r0, #0 59 mov pc, lr 60ENDPROC(__get_user_2) 61 62ENTRY(__get_user_4) 63 check_uaccess r0, 4, r1, r2, __get_user_bad 644: TUSER(ldr) r2, [r0] 65 mov r0, #0 66 mov pc, lr 67ENDPROC(__get_user_4) 68 69__get_user_bad: 70 mov r2, #0 71 mov r0, #-EFAULT 72 mov pc, lr 73ENDPROC(__get_user_bad) 74 75.pushsection __ex_table, "a" 76 .long 1b, __get_user_bad 77 .long 2b, __get_user_bad 78 .long 3b, __get_user_bad 79 .long 4b, __get_user_bad 80.popsection 81