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- // SPDX-License-Identifier: GPL-2.0+
- /*
- * The 'kaslrseed' command takes bytes from the hardware random number
- * generator and uses them to set the kaslr-seed value in the chosen node.
- *
- * Copyright (c) 2021, Chris Morgan <macromorgan@hotmail.com>
- */
- #include <common.h>
- #include <command.h>
- #include <dm.h>
- #include <hexdump.h>
- #include <malloc.h>
- #include <rng.h>
- #include <fdt_support.h>
- static int do_kaslr_seed(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
- {
- size_t n = 0x8;
- struct udevice *dev;
- u64 *buf;
- int nodeoffset;
- int ret = CMD_RET_SUCCESS;
- if (uclass_get_device(UCLASS_RNG, 0, &dev) || !dev) {
- printf("No RNG device\n");
- return CMD_RET_FAILURE;
- }
- buf = malloc(n);
- if (!buf) {
- printf("Out of memory\n");
- return CMD_RET_FAILURE;
- }
- if (dm_rng_read(dev, buf, n)) {
- printf("Reading RNG failed\n");
- return CMD_RET_FAILURE;
- }
- if (!working_fdt) {
- printf("No FDT memory address configured. Please configure\n"
- "the FDT address via \"fdt addr <address>\" command.\n"
- "Aborting!\n");
- return CMD_RET_FAILURE;
- }
- ret = fdt_check_header(working_fdt);
- if (ret < 0) {
- printf("fdt_chosen: %s\n", fdt_strerror(ret));
- return CMD_RET_FAILURE;
- }
- nodeoffset = fdt_find_or_add_subnode(working_fdt, 0, "chosen");
- if (nodeoffset < 0) {
- printf("Reading chosen node failed\n");
- return CMD_RET_FAILURE;
- }
- ret = fdt_setprop(working_fdt, nodeoffset, "kaslr-seed", buf, sizeof(buf));
- if (ret < 0) {
- printf("Unable to set kaslr-seed on chosen node: %s\n", fdt_strerror(ret));
- return CMD_RET_FAILURE;
- }
- free(buf);
- return ret;
- }
- #ifdef CONFIG_SYS_LONGHELP
- static char kaslrseed_help_text[] =
- "[n]\n"
- " - append random bytes to chosen kaslr-seed node\n";
- #endif
- U_BOOT_CMD(
- kaslrseed, 1, 0, do_kaslr_seed,
- "feed bytes from the hardware random number generator to the kaslr-seed",
- kaslrseed_help_text
- );
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