LXR linux/arch/hexagon/mm/copy_from

   1/*
   2 * User memory copy functions for kernel
   3 *
   4 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License version 2 and
   8 * only version 2 as published by the Free Software Foundation.
   9 *
  10 * This program is distributed in the hope that it will be useful,
  11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 * GNU General Public License for more details.
  14 *
  15 * You should have received a copy of the GNU General Public License
  16 * along with this program; if not, write to the Free Software
  17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  18 * 02110-1301, USA.
  19 */
  20
  21/*
  22 * The right way to do this involves valignb
  23 * The easy way to do this is only speed up src/dest similar alignment.
  24 */
  25
  26/*
  27 * Copy to/from user are the same, except that for packets with a load and
  28 * a store, I don't know how to tell which kind of exception we got.
  29 * Therefore, we duplicate the function, and handle faulting addresses
  30 * differently for each function
  31 */
  32
  33/*
  34 * copy from user: loads can fault
  35 */
  36#define src_sav r13
  37#define dst_sav r12
  38#define src_dst_sav r13:12
  39#define d_dbuf r15:14
  40#define w_dbuf r15
  41
  42#define dst r0
  43#define src r1
  44#define bytes r2
  45#define loopcount r5
  46
  47#define FUNCNAME __copy_from_user_hexagon
  48#include "copy_user_template.S"
  49
  50        /* LOAD FAULTS from COPY_FROM_USER */
  51
  52        /* Alignment loop.  r2 has been updated. Return it. */
  53        .falign
  541009:
  552009:
  564009:
  57        {
  58                r0 = r2
  59                jumpr r31
  60        }
  61        /* Normal copy loops. Do epilog. Use src-src_sav to compute distance */
  62        /* X - (A - B) == X + B - A */
  63        .falign
  648089:
  65        {
  66                memd(dst) = d_dbuf
  67                r2 += sub(src_sav,src)
  68        }
  69        {
  70                r0 = r2
  71                jumpr r31
  72        }
  73        .falign
  744089:
  75        {
  76                memw(dst) = w_dbuf
  77                r2 += sub(src_sav,src)
  78        }
  79        {
  80                r0 = r2
  81                jumpr r31
  82        }
  83        .falign
  842089:
  85        {
  86                memh(dst) = w_dbuf
  87                r2 += sub(src_sav,src)
  88        }
  89        {
  90                r0 = r2
  91                jumpr r31
  92        }
  93        .falign
  941089:
  95        {
  96                memb(dst) = w_dbuf
  97                r2 += sub(src_sav,src)
  98        }
  99        {
 100                r0 = r2
 101                jumpr r31
 102        }
 103
 104        /* COPY FROM USER: only loads can fail */
 105
 106        .section __ex_table,"a"
 107        .long 1000b,1009b
 108        .long 2000b,2009b
 109        .long 4000b,4009b
 110        .long 8080b,8089b
 111        .long 4080b,4089b
 112        .long 2080b,2089b
 113        .long 1080b,1089b
 114        .previous
 115