LXR linux/arch/arm64/lib/copy_from

   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
  63SYM_FUNC_END(__arch_copy_from_user)
  64EXPORT_SYMBOL(__arch_copy_from_user)
  65
  66        .section .fixup,"ax"
  67        .align  2
  689997:   cmp     dst, dstin
  69        b.ne    9998f
  70        // Before being absolutely sure we couldn't copy anything, try harder
  71USER(9998f, ldtrb tmp1w, [srcin])
  72        strb    tmp1w, [dst], #1
  739998:   sub     x0, end, dst                    // bytes not copied
  74        ret
  75        .previous
  76