hw/nvram/chrp_nvram.c

   1 /*
   2  * Common Hardware Reference Platform NVRAM helper functions.
   3  *
   4  * The CHRP NVRAM layout is used by OpenBIOS and SLOF. See CHRP
   5  * specification, chapter 8, or the LoPAPR specification for details
   6  * about the NVRAM layout.
   7  *
   8  * This code is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published
  10  * by the Free Software Foundation; either version 2 of the License,
  11  * or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22 #include "qemu/osdep.h"
  23 #include "qemu/cutils.h"
  24 #include "qemu/error-report.h"
  25 #include "hw/nvram/chrp_nvram.h"
  26 #include "sysemu/sysemu.h"
  27
  28 static int chrp_nvram_set_var(uint8_t *nvram, int addr, const char *str,
  29                               int max_len)
  30 {
  31     int len;
  32
  33     len = strlen(str) + 1;
  34
  35     if (max_len < len) {
  36         return -1;
  37     }
  38
  39     memcpy(&nvram[addr], str, len);
  40
  41     return addr + len;
  42 }
  43
  44 /**
  45  * Create a "system partition", used for the Open Firmware
  46  * environment variables.
  47  */
  48 int chrp_nvram_create_system_partition(uint8_t *data, int min_len, int max_len)
  49 {
  50     ChrpNvramPartHdr *part_header;
  51     unsigned int i;
  52     int end;
  53
  54     if (max_len < sizeof(*part_header)) {
  55         goto fail;
  56     }
  57
  58     part_header = (ChrpNvramPartHdr *)data;
  59     part_header->signature = CHRP_NVPART_SYSTEM;
  60     pstrcpy(part_header->name, sizeof(part_header->name), "system");
  61
  62     end = sizeof(ChrpNvramPartHdr);
  63     for (i = 0; i < nb_prom_envs; i++) {
  64         end = chrp_nvram_set_var(data, end, prom_envs[i], max_len - end);
  65         if (end == -1) {
  66             goto fail;
  67         }
  68     }
  69
  70     /* End marker */
  71     data[end++] = '\0';
  72
  73     end = (end + 15) & ~15;
  74     /* XXX: OpenBIOS is not able to grow up a partition. Leave some space for
  75        new variables. */
  76     if (end < min_len) {
  77         end = min_len;
  78     }
  79     chrp_nvram_finish_partition(part_header, end);
  80
  81     return end;
  82
  83 fail:
  84     error_report("NVRAM is too small. Try to pass less data to -prom-env");
  85     exit(EXIT_FAILURE);
  86 }
  87
  88 /**
  89  * Create a "free space" partition
  90  */
  91 int chrp_nvram_create_free_partition(uint8_t *data, int len)
  92 {
  93     ChrpNvramPartHdr *part_header;
  94
  95     part_header = (ChrpNvramPartHdr *)data;
  96     part_header->signature = CHRP_NVPART_FREE;
  97     pstrcpy(part_header->name, sizeof(part_header->name), "free");
  98
  99     chrp_nvram_finish_partition(part_header, len);
 100
 101     return len;
 102 }