copy_from_user.S (1407B)
1/* SPDX-License-Identifier: GPL-2.0-only */ 2/* 3 * Copyright (C) 2012 ARM Ltd. 4 */ 5 6#include <linux/linkage.h> 7 8#include <asm/asm-uaccess.h> 9#include <asm/assembler.h> 10#include <asm/cache.h> 11 12/* 13 * Copy from user space to a kernel buffer (alignment handled by the hardware) 14 * 15 * Parameters: 16 * x0 - to 17 * x1 - from 18 * x2 - n 19 * Returns: 20 * x0 - bytes not copied 21 */ 22 23 .macro ldrb1 reg, ptr, val 24 user_ldst 9998f, ldtrb, \reg, \ptr, \val 25 .endm 26 27 .macro strb1 reg, ptr, val 28 strb \reg, [\ptr], \val 29 .endm 30 31 .macro ldrh1 reg, ptr, val 32 user_ldst 9997f, ldtrh, \reg, \ptr, \val 33 .endm 34 35 .macro strh1 reg, ptr, val 36 strh \reg, [\ptr], \val 37 .endm 38 39 .macro ldr1 reg, ptr, val 40 user_ldst 9997f, ldtr, \reg, \ptr, \val 41 .endm 42 43 .macro str1 reg, ptr, val 44 str \reg, [\ptr], \val 45 .endm 46 47 .macro ldp1 reg1, reg2, ptr, val 48 user_ldp 9997f, \reg1, \reg2, \ptr, \val 49 .endm 50 51 .macro stp1 reg1, reg2, ptr, val 52 stp \reg1, \reg2, [\ptr], \val 53 .endm 54 55end .req x5 56srcin .req x15 57SYM_FUNC_START(__arch_copy_from_user) 58 add end, x0, x2 59 mov srcin, x1 60#include "copy_template.S" 61 mov x0, #0 // Nothing to copy 62 ret 63 64 // Exception fixups 659997: cmp dst, dstin 66 b.ne 9998f 67 // Before being absolutely sure we couldn't copy anything, try harder 68USER(9998f, ldtrb tmp1w, [srcin]) 69 strb tmp1w, [dst], #1 709998: sub x0, end, dst // bytes not copied 71 ret 72SYM_FUNC_END(__arch_copy_from_user) 73EXPORT_SYMBOL(__arch_copy_from_user)