root/arch/arm64/lib/copy_from_user.S

   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 ptr, regB, val
  24         uao_user_alternative 9998f, ldrb, ldtrb, \ptr, \regB, \val
  25         .endm
  26 
  27         .macro strb1 ptr, regB, val
  28         strb \ptr, [\regB], \val
  29         .endm
  30 
  31         .macro ldrh1 ptr, regB, val
  32         uao_user_alternative 9998f, ldrh, ldtrh, \ptr, \regB, \val
  33         .endm
  34 
  35         .macro strh1 ptr, regB, val
  36         strh \ptr, [\regB], \val
  37         .endm
  38 
  39         .macro ldr1 ptr, regB, val
  40         uao_user_alternative 9998f, ldr, ldtr, \ptr, \regB, \val
  41         .endm
  42 
  43         .macro str1 ptr, regB, val
  44         str \ptr, [\regB], \val
  45         .endm
  46 
  47         .macro ldp1 ptr, regB, regC, val
  48         uao_ldp 9998f, \ptr, \regB, \regC, \val
  49         .endm
  50 
  51         .macro stp1 ptr, regB, regC, val
  52         stp \ptr, \regB, [\regC], \val
  53         .endm
  54 
  55 end     .req    x5
  56 ENTRY(__arch_copy_from_user)
  57         add     end, x0, x2
  58 #include "copy_template.S"
  59         mov     x0, #0                          // Nothing to copy
  60         ret
  61 ENDPROC(__arch_copy_from_user)
  62 EXPORT_SYMBOL(__arch_copy_from_user)
  63 
  64         .section .fixup,"ax"
  65         .align  2
  66 9998:   sub     x0, end, dst                    // bytes not copied
  67         ret
  68         .previous