payloads/libpayload/libc/fmap.c

   1 /*
   2  *
   3  * Copyright (C) 2015 Google Inc.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. The name of the author may not be used to endorse or promote products
  14  *    derived from this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #include <libpayload-config.h>
  30 #include <libpayload.h>
  31 #include <commonlib/bsd/fmap_serialized.h>
  32 #include <coreboot_tables.h>
  33 #include <cbfs.h>
  34 #include <boot_device.h>
  35 #include <stdint.h>
  36 #include <arch/virtual.h>
  37
  38 /* Private fmap cache. */
  39 static struct fmap *_fmap_cache;
  40
  41 static enum cb_err fmap_find_area(struct fmap *fmap, const char *name, size_t *offset,
  42                                   size_t *size)
  43 {
  44         for (size_t i = 0; i < le32toh(fmap->nareas); ++i) {
  45                 if (strncmp((const char *)fmap->areas[i].name, name, FMAP_STRLEN) != 0)
  46                         continue;
  47                 if (offset)
  48                         *offset = le32toh(fmap->areas[i].offset);
  49                 if (size)
  50                         *size = le32toh(fmap->areas[i].size);
  51                 return CB_SUCCESS;
  52         }
  53
  54         return CB_ERR;
  55 }
  56
  57 static bool fmap_is_signature_valid(struct fmap *fmap)
  58 {
  59         return memcmp(fmap->signature, FMAP_SIGNATURE, sizeof(fmap->signature)) == 0;
  60 }
  61
  62 static bool fmap_setup_cache(void)
  63 {
  64         /* Use FMAP cache if available */
  65         if (lib_sysinfo.fmap_cache
  66             && fmap_is_signature_valid((struct fmap *)phys_to_virt(lib_sysinfo.fmap_cache))) {
  67                 _fmap_cache = (struct fmap *)phys_to_virt(lib_sysinfo.fmap_cache);
  68                 return true;
  69         }
  70
  71         return false;
  72 }
  73
  74 enum cb_err fmap_locate_area(const char *name, size_t *offset, size_t *size)
  75 {
  76         if (!_fmap_cache && !fmap_setup_cache())
  77                 return CB_ERR;
  78
  79         return fmap_find_area(_fmap_cache, name, offset, size);
  80 }