LXR linux/arch/i386/lib/putuser.S

   1/*
   2 * __put_user functions.
   3 *
   4 * (C) Copyright 2005 Linus Torvalds
   5 *
   6 * These functions have a non-standard call interface
   7 * to make them more efficient, especially as they
   8 * return an error value in addition to the "real"
   9 * return value.
  10 */
  11#include <linux/linkage.h>
  12#include <asm/dwarf2.h>
  13#include <asm/thread_info.h>
  14
  15
  16/*
  17 * __put_user_X
  18 *
  19 * Inputs:      %eax[:%edx] contains the data
  20 *              %ecx contains the address
  21 *
  22 * Outputs:     %eax is error code (0 or -EFAULT)
  23 *
  24 * These functions should not modify any other registers,
  25 * as they get called from within inline assembly.
  26 */
  27
  28#define ENTER   CFI_STARTPROC ; \
  29                pushl %ebx ; \
  30                CFI_ADJUST_CFA_OFFSET 4 ; \
  31                CFI_REL_OFFSET ebx, 0 ; \
  32                GET_THREAD_INFO(%ebx)
  33#define EXIT    popl %ebx ; \
  34                CFI_ADJUST_CFA_OFFSET -4 ; \
  35                CFI_RESTORE ebx ; \
  36                ret ; \
  37                CFI_ENDPROC
  38
  39.text
  40ENTRY(__put_user_1)
  41        ENTER
  42        cmpl TI_addr_limit(%ebx),%ecx
  43        jae bad_put_user
  441:      movb %al,(%ecx)
  45        xorl %eax,%eax
  46        EXIT
  47ENDPROC(__put_user_1)
  48
  49ENTRY(__put_user_2)
  50        ENTER
  51        movl TI_addr_limit(%ebx),%ebx
  52        subl $1,%ebx
  53        cmpl %ebx,%ecx
  54        jae bad_put_user
  552:      movw %ax,(%ecx)
  56        xorl %eax,%eax
  57        EXIT
  58ENDPROC(__put_user_2)
  59
  60ENTRY(__put_user_4)
  61        ENTER
  62        movl TI_addr_limit(%ebx),%ebx
  63        subl $3,%ebx
  64        cmpl %ebx,%ecx
  65        jae bad_put_user
  663:      movl %eax,(%ecx)
  67        xorl %eax,%eax
  68        EXIT
  69ENDPROC(__put_user_4)
  70
  71ENTRY(__put_user_8)
  72        ENTER
  73        movl TI_addr_limit(%ebx),%ebx
  74        subl $7,%ebx
  75        cmpl %ebx,%ecx
  76        jae bad_put_user
  774:      movl %eax,(%ecx)
  785:      movl %edx,4(%ecx)
  79        xorl %eax,%eax
  80        EXIT
  81ENDPROC(__put_user_8)
  82
  83bad_put_user:
  84        CFI_STARTPROC simple
  85        CFI_DEF_CFA esp, 2*4
  86        CFI_OFFSET eip, -1*4
  87        CFI_OFFSET ebx, -2*4
  88        movl $-14,%eax
  89        EXIT
  90END(bad_put_user)
  91
  92.section __ex_table,"a"
  93        .long 1b,bad_put_user
  94        .long 2b,bad_put_user
  95        .long 3b,bad_put_user
  96        .long 4b,bad_put_user
  97        .long 5b,bad_put_user
  98.previous
  99