arch/arm/lib/copy_to_user.S

   1 /*
   2  *  linux/arch/arm/lib/copy_to_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_to_user(void *to, const void *from, size_t n)
  21  *
  22  * Purpose:
  23  *
  24  *      copy a block to user memory from kernel memory
  25  *
  26  * Params:
  27  *
  28  *      to = user memory
  29  *      from = kernel memory
  30  *      n = number of bytes to copy
  31  *
  32  * Return value:
  33  *
  34  *      Number of bytes NOT copied.
  35  */
  36
  37 #define LDR1W_SHIFT     0
  38 #ifndef CONFIG_THUMB2_KERNEL
  39 #define STR1W_SHIFT     0
  40 #else
  41 #define STR1W_SHIFT     1
  42 #endif
  43
  44         .macro ldr1w ptr reg abort
  45         W(ldr) \reg, [\ptr], #4
  46         .endm
  47
  48         .macro ldr4w ptr reg1 reg2 reg3 reg4 abort
  49         ldmia \ptr!, {\reg1, \reg2, \reg3, \reg4}
  50         .endm
  51
  52         .macro ldr8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
  53         ldmia \ptr!, {\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8}
  54         .endm
  55
  56         .macro ldr1b ptr reg cond=al abort
  57         ldr\cond\()b \reg, [\ptr], #1
  58         .endm
  59
  60         .macro str1w ptr reg abort
  61         strusr  \reg, \ptr, 4, abort=\abort
  62         .endm
  63
  64         .macro str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
  65         str1w \ptr, \reg1, \abort
  66         str1w \ptr, \reg2, \abort
  67         str1w \ptr, \reg3, \abort
  68         str1w \ptr, \reg4, \abort
  69         str1w \ptr, \reg5, \abort
  70         str1w \ptr, \reg6, \abort
  71         str1w \ptr, \reg7, \abort
  72         str1w \ptr, \reg8, \abort
  73         .endm
  74
  75         .macro str1b ptr reg cond=al abort
  76         strusr  \reg, \ptr, 1, \cond, abort=\abort
  77         .endm
  78
  79         .macro enter reg1 reg2
  80         mov     r3, #0
  81         stmdb   sp!, {r0, r2, r3, \reg1, \reg2}
  82         .endm
  83
  84         .macro usave reg1 reg2
  85         UNWIND( .save {r0, r2, r3, \reg1, \reg2}        )
  86         .endm
  87
  88         .macro exit reg1 reg2
  89         add     sp, sp, #8
  90         ldmfd   sp!, {r0, \reg1, \reg2}
  91         .endm
  92
  93         .text
  94
  95 ENTRY(__copy_to_user_std)
  96 WEAK(arm_copy_to_user)
  97
  98 #include "copy_template.S"
  99
 100 ENDPROC(arm_copy_to_user)
 101 ENDPROC(__copy_to_user_std)
 102
 103         .pushsection .text.fixup,"ax"
 104         .align 0
 105         copy_abort_preamble
 106         ldmfd   sp!, {r1, r2, r3}
 107         sub     r0, r0, r1
 108         rsb     r0, r0, r2
 109         copy_abort_end
 110         .popsection
 111