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
prom_getbootargs(void)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 }
45