arch/arm/lib/copy_from_user.S

   1 /*
   2  *  linux/arch/arm/lib/copy_from_user.S
   3  *
   4  *  Author:     Nicolas Pitre
   5  *  Created:    Sep 29, 2005
   6  *  Copyright:  MontaVista Software, Inc.
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License version 2 as
  10  *  published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/linkage.h>
  14 #include <asm/assembler.h>
  15 #include <asm/unwind.h>
  16
  17 /*
  18  * Prototype:
  19  *
  20  *      size_t arm_copy_from_user(void *to, const void *from, size_t n)
  21  *
  22  * Purpose:
  23  *
  24  *      copy a block to kernel memory from user memory
  25  *
  26  * Params:
  27  *
  28  *      to = kernel memory
  29  *      from = user memory
  30  *      n = number of bytes to copy
  31  *
  32  * Return value:
  33  *
  34  *      Number of bytes NOT copied.
  35  */
  36
  37 #ifndef CONFIG_THUMB2_KERNEL
  38 #define LDR1W_SHIFT     0
  39 #else
  40 #define LDR1W_SHIFT     1
  41 #endif
  42 #define STR1W_SHIFT     0
  43
  44         .macro ldr1w ptr reg abort
  45         ldrusr  \reg, \ptr, 4, abort=\abort
  46         .endm
  47
  48         .macro ldr4w ptr reg1 reg2 reg3 reg4 abort
  49         ldr1w \ptr, \reg1, \abort
  50         ldr1w \ptr, \reg2, \abort
  51         ldr1w \ptr, \reg3, \abort
  52         ldr1w \ptr, \reg4, \abort
  53         .endm
  54
  55         .macro ldr8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
  56         ldr4w \ptr, \reg1, \reg2, \reg3, \reg4, \abort
  57         ldr4w \ptr, \reg5, \reg6, \reg7, \reg8, \abort
  58         .endm
  59
  60         .macro ldr1b ptr reg cond=al abort
  61         ldrusr  \reg, \ptr, 1, \cond, abort=\abort
  62         .endm
  63
  64         .macro str1w ptr reg abort
  65         W(str) \reg, [\ptr], #4
  66         .endm
  67
  68         .macro str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
  69         stmia \ptr!, {\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8}
  70         .endm
  71
  72         .macro str1b ptr reg cond=al abort
  73         str\cond\()b \reg, [\ptr], #1
  74         .endm
  75
  76         .macro enter reg1 reg2
  77         mov     r3, #0
  78         stmdb   sp!, {r0, r2, r3, \reg1, \reg2}
  79         .endm
  80
  81         .macro usave reg1 reg2
  82         UNWIND( .save {r0, r2, r3, \reg1, \reg2}        )
  83         .endm
  84
  85         .macro exit reg1 reg2
  86         add     sp, sp, #8
  87         ldmfd   sp!, {r0, \reg1, \reg2}
  88         .endm
  89
  90         .text
  91
  92 ENTRY(arm_copy_from_user)
  93
  94 #include "copy_template.S"
  95
  96 ENDPROC(arm_copy_from_user)
  97
  98         .pushsection .fixup,"ax"
  99         .align 0
 100         copy_abort_preamble
 101         ldmfd   sp!, {r1, r2}
 102         sub     r3, r0, r1
 103         rsb     r1, r3, r2
 104         str     r1, [sp]
 105         bl      __memzero
 106         ldr     r0, [sp], #4
 107         copy_abort_end
 108         .popsection
 109