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chrp_nvram.c (2764B)

      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 }