arch/arm64/lib/copy_from_user.S

   1 /*
   2  * Copyright (C) 2012 ARM Ltd.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16
  17 #include <linux/linkage.h>
  18
  19 #include <asm/cache.h>
  20 #include <linux/uaccess.h>
  21
  22 /*
  23  * Copy from user space to a kernel buffer (alignment handled by the hardware)
  24  *
  25  * Parameters:
  26  *      x0 - to
  27  *      x1 - from
  28  *      x2 - n
  29  * Returns:
  30  *      x0 - bytes not copied
  31  */
  32
  33         .macro ldrb1 ptr, regB, val
  34         uao_user_alternative 9998f, ldrb, ldtrb, \ptr, \regB, \val
  35         .endm
  36
  37         .macro strb1 ptr, regB, val
  38         strb \ptr, [\regB], \val
  39         .endm
  40
  41         .macro ldrh1 ptr, regB, val
  42         uao_user_alternative 9998f, ldrh, ldtrh, \ptr, \regB, \val
  43         .endm
  44
  45         .macro strh1 ptr, regB, val
  46         strh \ptr, [\regB], \val
  47         .endm
  48
  49         .macro ldr1 ptr, regB, val
  50         uao_user_alternative 9998f, ldr, ldtr, \ptr, \regB, \val
  51         .endm
  52
  53         .macro str1 ptr, regB, val
  54         str \ptr, [\regB], \val
  55         .endm
  56
  57         .macro ldp1 ptr, regB, regC, val
  58         uao_ldp 9998f, \ptr, \regB, \regC, \val
  59         .endm
  60
  61         .macro stp1 ptr, regB, regC, val
  62         stp \ptr, \regB, [\regC], \val
  63         .endm
  64
  65 end     .req    x5
  66 ENTRY(__arch_copy_from_user)
  67         uaccess_enable_not_uao x3, x4
  68         add     end, x0, x2
  69 #include "copy_template.S"
  70         uaccess_disable_not_uao x3
  71         mov     x0, #0                          // Nothing to copy
  72         ret
  73 ENDPROC(__arch_copy_from_user)
  74
  75         .section .fixup,"ax"
  76         .align  2
  77 9998:   sub     x0, end, dst                    // bytes not copied
  78         ret
  79         .previous