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 32ENTRY(__get_user_1) 331: ldrbt r2, [r0] 34 mov r0, #0 35 mov pc, lr 36ENDPROC(__get_user_1) 37 38ENTRY(__get_user_2) 39#ifdef CONFIG_THUMB2_KERNEL 402: ldrbt r2, [r0] 413: ldrbt r3, [r0, #1] 42#else 432: ldrbt r2, [r0], #1 443: ldrbt r3, [r0] 45#endif 46#ifndef __ARMEB__ 47 orr r2, r2, r3, lsl #8 48#else 49 orr r2, r3, r2, lsl #8 50#endif 51 mov r0, #0 52 mov pc, lr 53ENDPROC(__get_user_2) 54 55ENTRY(__get_user_4) 564: ldrt r2, [r0] 57 mov r0, #0 58 mov pc, lr 59ENDPROC(__get_user_4) 60 61__get_user_bad: 62 mov r2, #0 63 mov r0, #-EFAULT 64 mov pc, lr 65ENDPROC(__get_user_bad) 66 67.pushsection __ex_table, "a" 68 .long 1b, __get_user_bad 69 .long 2b, __get_user_bad 70 .long 3b, __get_user_bad 71 .long 4b, __get_user_bad 72.popsection 73