cmd/kaslrseed.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * The 'kaslrseed' command takes bytes from the hardware random number
   4  * generator and uses them to set the kaslr-seed value in the chosen node.
   5  *
   6  * Copyright (c) 2021, Chris Morgan <macromorgan@hotmail.com>
   7  */
   8
   9 #include <command.h>
  10 #include <dm.h>
  11 #include <hexdump.h>
  12 #include <malloc.h>
  13 #include <rng.h>
  14 #include <fdt_support.h>
  15
  16 static int do_kaslr_seed(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
  17 {
  18         int err = CMD_RET_SUCCESS;
  19
  20         printf("Notice: a /chosen/kaslr-seed is automatically added to the device-tree when booted via booti/bootm/bootz therefore using this command is likely no longer needed\n");
  21
  22         if (!working_fdt) {
  23                 printf("No FDT memory address configured. Please configure\n"
  24                        "the FDT address via \"fdt addr <address>\" command.\n"
  25                        "Aborting!\n");
  26                 err = CMD_RET_FAILURE;
  27         } else {
  28                 if (fdt_kaslrseed(working_fdt, true) < 0)
  29                         err = CMD_RET_FAILURE;
  30         }
  31
  32         return cmd_process_error(cmdtp, err);
  33 }
  34
  35 U_BOOT_LONGHELP(kaslrseed,
  36         "\n"
  37         "  - append random bytes to chosen kaslr-seed node\n");
  38
  39 U_BOOT_CMD(
  40         kaslrseed, 1, 0, do_kaslr_seed,
  41         "feed bytes from the hardware random number generator to the kaslr-seed",
  42         kaslrseed_help_text
  43 );