LXR linux/arch/cris/arch-v10/lib/csumcpfruser.S

   1/*
   2 * Add-on to transform csum_partial_copy_nocheck in checksumcopy.S into
   3 * csum_partial_copy_from_user by adding exception records.
   4 *
   5 * Copyright (C) 2001 Axis Communications AB.
   6 *
   7 * Author: Hans-Peter Nilsson.
   8 */
   9
  10#include <asm/errno.h>
  11
  12/* Same function body, but a different name.  If we just added exception
  13   records to _csum_partial_copy_nocheck and made it generic, we wouldn't
  14   know a user fault from a kernel fault and we would have overhead in
  15   each kernel caller for the error-pointer argument.
  16
  17   unsigned int csum_partial_copy_from_user
  18     (const char *src, char *dst, int len, unsigned int sum, int *errptr);
  19
  20   Note that the errptr argument is only set if we encounter an error.
  21   It is conveniently located on the stack, so the normal function body
  22   does not have to handle it.  */
  23
  24#define csum_partial_copy_nocheck csum_partial_copy_from_user
  25
  26/* There are local labels numbered 1, 2 and 3 present to mark the
  27   different from-user accesses.  */
  28#include "checksumcopy.S"
  29
  30        .section .fixup,"ax"
  31
  32;; Here from the movem loop; restore stack.
  334:
  34        movem   [$sp+],$r8
  35;; r12 is already decremented.  Add back chunk_size-2.
  36        addq    40-2,$r12
  37
  38;; Here from the word loop; r12 is off by 2; add it back.
  395:
  40        addq    2,$r12
  41
  42;; Here from a failing single byte.
  436:
  44
  45;; Signal in *errptr that we had a failing access.
  46        moveq   -EFAULT,$r9
  47        move.d  $r9,[[$sp]]
  48
  49;; Clear the rest of the destination area using memset.  Preserve the
  50;; checksum for the readable bytes.
  51        push    $srp
  52        push    $r13
  53        move.d  $r11,$r10
  54        clear.d $r11
  55        jsr     memset
  56        pop     $r10
  57        jump    [$sp+]
  58
  59        .previous
  60        .section __ex_table,"a"
  61        .dword 1b,4b
  62        .dword 2b,5b
  63        .dword 3b,6b
  64        .previous
  65