LXR linux/arch/hexagon/mm/copy_from

   1/* SPDX-License-Identifier: GPL-2.0-only */
   2/*
   3 * User memory copy functions for kernel
   4 *
   5 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
   6 */
   7
   8/*
   9 * The right way to do this involves valignb
  10 * The easy way to do this is only speed up src/dest similar alignment.
  11 */
  12
  13/*
  14 * Copy to/from user are the same, except that for packets with a load and
  15 * a store, I don't know how to tell which kind of exception we got.
  16 * Therefore, we duplicate the function, and handle faulting addresses
  17 * differently for each function
  18 */
  19
  20/*
  21 * copy from user: loads can fault
  22 */
  23#define src_sav r13
  24#define dst_sav r12
  25#define src_dst_sav r13:12
  26#define d_dbuf r15:14
  27#define w_dbuf r15
  28
  29#define dst r0
  30#define src r1
  31#define bytes r2
  32#define loopcount r5
  33
  34#define FUNCNAME raw_copy_from_user
  35#include "copy_user_template.S"
  36
  37        /* LOAD FAULTS from COPY_FROM_USER */
  38
  39        /* Alignment loop.  r2 has been updated. Return it. */
  40        .falign
  411009:
  422009:
  434009:
  44        {
  45                r0 = r2
  46                jumpr r31
  47        }
  48        /* Normal copy loops. Do epilog. Use src-src_sav to compute distance */
  49        /* X - (A - B) == X + B - A */
  50        .falign
  518089:
  52        {
  53                memd(dst) = d_dbuf
  54                r2 += sub(src_sav,src)
  55        }
  56        {
  57                r0 = r2
  58                jumpr r31
  59        }
  60        .falign
  614089:
  62        {
  63                memw(dst) = w_dbuf
  64                r2 += sub(src_sav,src)
  65        }
  66        {
  67                r0 = r2
  68                jumpr r31
  69        }
  70        .falign
  712089:
  72        {
  73                memh(dst) = w_dbuf
  74                r2 += sub(src_sav,src)
  75        }
  76        {
  77                r0 = r2
  78                jumpr r31
  79        }
  80        .falign
  811089:
  82        {
  83                memb(dst) = w_dbuf
  84                r2 += sub(src_sav,src)
  85        }
  86        {
  87                r0 = r2
  88                jumpr r31
  89        }
  90
  91        /* COPY FROM USER: only loads can fail */
  92
  93        .section __ex_table,"a"
  94        .long 1000b,1009b
  95        .long 2000b,2009b
  96        .long 4000b,4009b
  97        .long 8080b,8089b
  98        .long 4080b,4089b
  99        .long 2080b,2089b
 100        .long 1080b,1089b
 101        .previous
 102