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/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 from user space to 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
  36         .macro ldrb1 ptr, regB, val
  37         uao_user_alternative 9998f, ldrb, ldtrb, \ptr, \regB, \val
  38         .endm
  39
  40         .macro strb1 ptr, regB, val
  41         strb \ptr, [\regB], \val
  42         .endm
  43
  44         .macro ldrh1 ptr, regB, val
  45         uao_user_alternative 9998f, ldrh, ldtrh, \ptr, \regB, \val
  46         .endm
  47
  48         .macro strh1 ptr, regB, val
  49         strh \ptr, [\regB], \val
  50         .endm
  51
  52         .macro ldr1 ptr, regB, val
  53         uao_user_alternative 9998f, ldr, ldtr, \ptr, \regB, \val
  54         .endm
  55
  56         .macro str1 ptr, regB, val
  57         str \ptr, [\regB], \val
  58         .endm
  59
  60         .macro ldp1 ptr, regB, regC, val
  61         uao_ldp 9998f, \ptr, \regB, \regC, \val
  62         .endm
  63
  64         .macro stp1 ptr, regB, regC, val
  65         stp \ptr, \regB, [\regC], \val
  66         .endm
  67
  68 end     .req    x5
  69 ENTRY(__arch_copy_from_user)
  70 ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(0)), ARM64_ALT_PAN_NOT_UAO, \
  71             CONFIG_ARM64_PAN)
  72         add     end, x0, x2
  73 #include "copy_template.S"
  74 ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(1)), ARM64_ALT_PAN_NOT_UAO, \
  75             CONFIG_ARM64_PAN)
  76         mov     x0, #0                          // Nothing to copy
  77         ret
  78 ENDPROC(__arch_copy_from_user)
  79
  80         .section .fixup,"ax"
  81         .align  2
  82 9998:
  83         sub     x0, end, dst
  84 9999:
  85         strb    wzr, [dst], #1                  // zero remaining buffer space
  86         cmp     dst, end
  87         b.lo    9999b
  88         ret
  89         .previous