com32/lib/syslinux/shuffle.c

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright 2007 H. Peter Anvin - All Rights Reserved
   4  *
   5  *   Permission is hereby granted, free of charge, to any person
   6  *   obtaining a copy of this software and associated documentation
   7  *   files (the "Software"), to deal in the Software without
   8  *   restriction, including without limitation the rights to use,
   9  *   copy, modify, merge, publish, distribute, sublicense, and/or
  10  *   sell copies of the Software, and to permit persons to whom
  11  *   the Software is furnished to do so, subject to the following
  12  *   conditions:
  13  *
  14  *   The above copyright notice and this permission notice shall
  15  *   be included in all copies or substantial portions of the Software.
  16  *
  17  *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  18  *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
  19  *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  20  *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
  21  *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  22  *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  23  *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  24  *   OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  * ----------------------------------------------------------------------- */
  27
  28 /*
  29  * shuffle.c
  30  *
  31  * Common code for "shuffle and boot" operation; generates a shuffle list
  32  * and puts it in the bounce buffer.  Returns the number of shuffle
  33  * descriptors.
  34  */
  35
  36 #include <stdlib.h>
  37 #include <inttypes.h>
  38 #include <com32.h>
  39 #include <syslinux/movebits.h>
  40
  41 struct shuffle_descriptor {
  42   uint32_t dst, src, len;
  43 };
  44
  45 int syslinux_prepare_shuffle(struct syslinux_movelist *fraglist,
  46                              struct syslinux_memmap *memmap)
  47 {
  48   struct syslinux_movelist *moves = NULL, *mp;
  49   struct syslinux_memmap *ml;
  50   struct shuffle_descriptor *dp;
  51   int np, rv = -1;
  52
  53   if (syslinux_compute_movelist(&moves, fraglist, memmap))
  54     goto bail;
  55
  56   dp = __com32.cs_bounce;
  57   np = 0;
  58
  59   /* Copy the move sequence into the bounce buffer */
  60   for (mp = moves; mp; mp = mp->next) {
  61     if (np >= 65536/12)
  62       goto bail;                /* Way too many descriptors... */
  63
  64     dp->dst = mp->dst;
  65     dp->src = mp->src;
  66     dp->len = mp->len;
  67     dp++; np++;
  68   }
  69
  70   /* Copy any zeroing operations into the bounce buffer */
  71   for (ml = memmap; ml->type != SMT_END; ml = ml->next) {
  72     if (ml->type == SMT_ZERO) {
  73       if (np >= 65536/12)
  74         goto bail;
  75
  76       dp->dst = ml->start;
  77       dp->src = (addr_t)-1;     /* bzero this region */
  78       dp->len = ml->next->start - ml->start;
  79       dp++; np++;
  80     }
  81   }
  82
  83   rv = np;
  84
  85  bail:
  86   /* This is safe only because free() doesn't use the bounce buffer!!!! */
  87   if (moves)
  88     syslinux_free_movelist(moves);
  89
  90   return rv;
  91 }