1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * bootstr.c: Boot string/argument acquisition from the PROM.
4 *
5 * Copyright(C) 1995 David S. Miller (davem@caip.rutgers.edu)
6 * Copyright(C) 1996,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
7 */
8
9 #include <linux/string.h>
10 #include <linux/init.h>
11 #include <asm/oplib.h>
12
13 /* WARNING: The boot loader knows that these next three variables come one right
14 * after another in the .data section. Do not move this stuff into
15 * the .bss section or it will break things.
16 */
17
18 /* We limit BARG_LEN to 1024 because this is the size of the
19 * 'barg_out' command line buffer in the SILO bootloader.
20 */
21 #define BARG_LEN 1024
22 struct {
23 int bootstr_len;
24 int bootstr_valid;
25 char bootstr_buf[BARG_LEN];
26 } bootstr_info = {
27 .bootstr_len = BARG_LEN,
28 #ifdef CONFIG_CMDLINE
29 .bootstr_valid = 1,
30 .bootstr_buf = CONFIG_CMDLINE,
31 #endif
32 };
33
34 char * __init
35 prom_getbootargs(void)
36 {
37 /* This check saves us from a panic when bootfd patches args. */
38 if (bootstr_info.bootstr_valid)
39 return bootstr_info.bootstr_buf;
40 prom_getstring(prom_chosen_node, "bootargs",
41 bootstr_info.bootstr_buf, BARG_LEN);
42 bootstr_info.bootstr_valid = 1;
43 return bootstr_info.bootstr_buf;
44 }