LXR linux/arch/arm/lib/copy_from

   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
  16/*
  17 * Prototype:
  18 *
  19 *      size_t __copy_from_user(void *to, const void *from, size_t n)
  20 *
  21 * Purpose:
  22 *
  23 *      copy a block to kernel memory from user memory
  24 *
  25 * Params:
  26 *
  27 *      to = kernel memory
  28 *      from = user memory
  29 *      n = number of bytes to copy
  30 *
  31 * Return value:
  32 *
  33 *      Number of bytes NOT copied.
  34 */
  35
  36#ifndef CONFIG_THUMB2_KERNEL
  37#define LDR1W_SHIFT     0
  38#else
  39#define LDR1W_SHIFT     1
  40#endif
  41#define STR1W_SHIFT     0
  42
  43        .macro ldr1w ptr reg abort
  44        ldrusr  \reg, \ptr, 4, abort=\abort
  45        .endm
  46
  47        .macro ldr4w ptr reg1 reg2 reg3 reg4 abort
  48        ldr1w \ptr, \reg1, \abort
  49        ldr1w \ptr, \reg2, \abort
  50        ldr1w \ptr, \reg3, \abort
  51        ldr1w \ptr, \reg4, \abort
  52        .endm
  53
  54        .macro ldr8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
  55        ldr4w \ptr, \reg1, \reg2, \reg3, \reg4, \abort
  56        ldr4w \ptr, \reg5, \reg6, \reg7, \reg8, \abort
  57        .endm
  58
  59        .macro ldr1b ptr reg cond=al abort
  60        ldrusr  \reg, \ptr, 1, \cond, abort=\abort
  61        .endm
  62
  63        .macro str1w ptr reg abort
  64        W(str) \reg, [\ptr], #4
  65        .endm
  66
  67        .macro str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
  68        stmia \ptr!, {\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8}
  69        .endm
  70
  71        .macro str1b ptr reg cond=al abort
  72        str\cond\()b \reg, [\ptr], #1
  73        .endm
  74
  75        .macro enter reg1 reg2
  76        mov     r3, #0
  77        stmdb   sp!, {r0, r2, r3, \reg1, \reg2}
  78        .endm
  79
  80        .macro exit reg1 reg2
  81        add     sp, sp, #8
  82        ldmfd   sp!, {r0, \reg1, \reg2}
  83        .endm
  84
  85        .text
  86
  87ENTRY(__copy_from_user)
  88
  89#include "copy_template.S"
  90
  91ENDPROC(__copy_from_user)
  92
  93        .pushsection .fixup,"ax"
  94        .align 0
  95        copy_abort_preamble
  96        ldmfd   sp!, {r1, r2}
  97        sub     r3, r0, r1
  98        rsb     r1, r3, r2
  99        str     r1, [sp]
 100        bl      __memzero
 101        ldr     r0, [sp], #4
 102        copy_abort_end
 103        .popsection
 104
 105