arch/arm64/lib/copy_to_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/alternative.h>
  20 #include <asm/assembler.h>
  21 #include <asm/cache.h>
  22 #include <asm/cpufeature.h>
  23 #include <asm/sysreg.h>
  24
  25 /*
  26  * Copy to user space from a kernel buffer (alignment handled by the hardware)
  27  *
  28  * Parameters:
  29  *      x0 - to
  30  *      x1 - from
  31  *      x2 - n
  32  * Returns:
  33  *      x0 - bytes not copied
  34  */
  35         .macro ldrb1 ptr, regB, val
  36         ldrb  \ptr, [\regB], \val
  37         .endm
  38
  39         .macro strb1 ptr, regB, val
  40         uao_user_alternative 9998f, strb, sttrb, \ptr, \regB, \val
  41         .endm
  42
  43         .macro ldrh1 ptr, regB, val
  44         ldrh  \ptr, [\regB], \val
  45         .endm
  46
  47         .macro strh1 ptr, regB, val
  48         uao_user_alternative 9998f, strh, sttrh, \ptr, \regB, \val
  49         .endm
  50
  51         .macro ldr1 ptr, regB, val
  52         ldr \ptr, [\regB], \val
  53         .endm
  54
  55         .macro str1 ptr, regB, val
  56         uao_user_alternative 9998f, str, sttr, \ptr, \regB, \val
  57         .endm
  58
  59         .macro ldp1 ptr, regB, regC, val
  60         ldp \ptr, \regB, [\regC], \val
  61         .endm
  62
  63         .macro stp1 ptr, regB, regC, val
  64         uao_stp 9998f, \ptr, \regB, \regC, \val
  65         .endm
  66
  67 end     .req    x5
  68 ENTRY(__arch_copy_to_user)
  69 ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(0)), ARM64_ALT_PAN_NOT_UAO, \
  70             CONFIG_ARM64_PAN)
  71         add     end, x0, x2
  72 #include "copy_template.S"
  73 ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(1)), ARM64_ALT_PAN_NOT_UAO, \
  74             CONFIG_ARM64_PAN)
  75         mov     x0, #0
  76         ret
  77 ENDPROC(__arch_copy_to_user)
  78
  79         .section .fixup,"ax"
  80         .align  2
  81 9998:   sub     x0, end, dst                    // bytes not copied
  82         ret
  83         .previous