1/* SPDX-License-Identifier: GPL-2.0 */
 2#ifndef _ASM_X86_BOOTPARAM_UTILS_H
 3#define _ASM_X86_BOOTPARAM_UTILS_H
 4
 5#include <asm/bootparam.h>
 6
 7/*
 8 * This file is included from multiple environments.  Do not
 9 * add completing #includes to make it standalone.
10 */
11
12/*
13 * Deal with bootloaders which fail to initialize unknown fields in
14 * boot_params to zero.  The list fields in this list are taken from
15 * analysis of kexec-tools; if other broken bootloaders initialize a
16 * different set of fields we will need to figure out how to disambiguate.
17 *
18 * Note: efi_info is commonly left uninitialized, but that field has a
19 * private magic, so it is better to leave it unchanged.
20 */
21static void sanitize_boot_params(struct boot_params *boot_params)
22{
23	/* 
24	 * IMPORTANT NOTE TO BOOTLOADER AUTHORS: do not simply clear
25	 * this field.  The purpose of this field is to guarantee
26	 * compliance with the x86 boot spec located in
27	 * Documentation/x86/boot.txt .  That spec says that the
28	 * *whole* structure should be cleared, after which only the
29	 * portion defined by struct setup_header (boot_params->hdr)
30	 * should be copied in.
31	 *
32	 * If you're having an issue because the sentinel is set, you
33	 * need to change the whole structure to be cleared, not this
34	 * (or any other) individual field, or you will soon have
35	 * problems again.
36	 */
37	if (boot_params->sentinel) {
38		/* fields in boot_params are left uninitialized, clear them */
39		memset(&boot_params->ext_ramdisk_image, 0,
40		       (char *)&boot_params->efi_info -
41			(char *)&boot_params->ext_ramdisk_image);
42		memset(&boot_params->kbd_status, 0,
43		       (char *)&boot_params->hdr -
44		       (char *)&boot_params->kbd_status);
45		memset(&boot_params->_pad7[0], 0,
46		       (char *)&boot_params->edd_mbr_sig_buffer[0] -
47			(char *)&boot_params->_pad7[0]);
48		memset(&boot_params->_pad8[0], 0,
49		       (char *)&boot_params->eddbuf[0] -
50			(char *)&boot_params->_pad8[0]);
51		memset(&boot_params->_pad9[0], 0, sizeof(boot_params->_pad9));
52	}
53}
54
55#endif /* _ASM_X86_BOOTPARAM_UTILS_H */

 
 1#ifndef _ASM_X86_BOOTPARAM_UTILS_H
 2#define _ASM_X86_BOOTPARAM_UTILS_H
 3
 4#include <asm/bootparam.h>
 5
 6/*
 7 * This file is included from multiple environments.  Do not
 8 * add completing #includes to make it standalone.
 9 */
10
11/*
12 * Deal with bootloaders which fail to initialize unknown fields in
13 * boot_params to zero.  The list fields in this list are taken from
14 * analysis of kexec-tools; if other broken bootloaders initialize a
15 * different set of fields we will need to figure out how to disambiguate.
16 *
17 * Note: efi_info is commonly left uninitialized, but that field has a
18 * private magic, so it is better to leave it unchanged.
19 */
20static void sanitize_boot_params(struct boot_params *boot_params)
21{
22	/* 
23	 * IMPORTANT NOTE TO BOOTLOADER AUTHORS: do not simply clear
24	 * this field.  The purpose of this field is to guarantee
25	 * compliance with the x86 boot spec located in
26	 * Documentation/x86/boot.txt .  That spec says that the
27	 * *whole* structure should be cleared, after which only the
28	 * portion defined by struct setup_header (boot_params->hdr)
29	 * should be copied in.
30	 *
31	 * If you're having an issue because the sentinel is set, you
32	 * need to change the whole structure to be cleared, not this
33	 * (or any other) individual field, or you will soon have
34	 * problems again.
35	 */
36	if (boot_params->sentinel) {
37		/* fields in boot_params are left uninitialized, clear them */
38		memset(&boot_params->ext_ramdisk_image, 0,
39		       (char *)&boot_params->efi_info -
40			(char *)&boot_params->ext_ramdisk_image);
41		memset(&boot_params->kbd_status, 0,
42		       (char *)&boot_params->hdr -
43		       (char *)&boot_params->kbd_status);
44		memset(&boot_params->_pad7[0], 0,
45		       (char *)&boot_params->edd_mbr_sig_buffer[0] -
46			(char *)&boot_params->_pad7[0]);
47		memset(&boot_params->_pad8[0], 0,
48		       (char *)&boot_params->eddbuf[0] -
49			(char *)&boot_params->_pad8[0]);
50		memset(&boot_params->_pad9[0], 0, sizeof(boot_params->_pad9));
51	}
52}
53
54#endif /* _ASM_X86_BOOTPARAM_UTILS_H */