root/arch/arm64/lib/copy_to_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 to user space from 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         .macro ldrb1 ptr, regB, val
  23         ldrb  \ptr, [\regB], \val
  24         .endm
  25 
  26         .macro strb1 ptr, regB, val
  27         uao_user_alternative 9998f, strb, sttrb, \ptr, \regB, \val
  28         .endm
  29 
  30         .macro ldrh1 ptr, regB, val
  31         ldrh  \ptr, [\regB], \val
  32         .endm
  33 
  34         .macro strh1 ptr, regB, val
  35         uao_user_alternative 9998f, strh, sttrh, \ptr, \regB, \val
  36         .endm
  37 
  38         .macro ldr1 ptr, regB, val
  39         ldr \ptr, [\regB], \val
  40         .endm
  41 
  42         .macro str1 ptr, regB, val
  43         uao_user_alternative 9998f, str, sttr, \ptr, \regB, \val
  44         .endm
  45 
  46         .macro ldp1 ptr, regB, regC, val
  47         ldp \ptr, \regB, [\regC], \val
  48         .endm
  49 
  50         .macro stp1 ptr, regB, regC, val
  51         uao_stp 9998f, \ptr, \regB, \regC, \val
  52         .endm
  53 
  54 end     .req    x5
  55 ENTRY(__arch_copy_to_user)
  56         add     end, x0, x2
  57 #include "copy_template.S"
  58         mov     x0, #0
  59         ret
  60 ENDPROC(__arch_copy_to_user)
  61 EXPORT_SYMBOL(__arch_copy_to_user)
  62 
  63         .section .fixup,"ax"
  64         .align  2
  65 9998:   sub     x0, end, dst                    // bytes not copied
  66         ret
  67         .previous