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git.proxmox.com Git - mirror_ubuntu-hirsute-kernel.git/blob - arch/x86/include/asm/bootparam_utils.h
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_BOOTPARAM_UTILS_H
3 #define _ASM_X86_BOOTPARAM_UTILS_H
5 #include <asm/bootparam.h>
8 * This file is included from multiple environments. Do not
9 * add completing #includes to make it standalone.
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.
18 * Note: efi_info is commonly left uninitialized, but that field has a
19 * private magic, so it is better to leave it unchanged.
21 static void sanitize_boot_params(struct boot_params
*boot_params
)
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.rst . 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.
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
37 if (boot_params
->sentinel
) {
38 /* fields in boot_params are left uninitialized, clear them */
39 boot_params
->acpi_rsdp_addr
= 0;
40 memset(&boot_params
->ext_ramdisk_image
, 0,
41 (char *)&boot_params
->efi_info
-
42 (char *)&boot_params
->ext_ramdisk_image
);
43 memset(&boot_params
->kbd_status
, 0,
44 (char *)&boot_params
->hdr
-
45 (char *)&boot_params
->kbd_status
);
46 memset(&boot_params
->_pad7
[0], 0,
47 (char *)&boot_params
->edd_mbr_sig_buffer
[0] -
48 (char *)&boot_params
->_pad7
[0]);
49 memset(&boot_params
->_pad8
[0], 0,
50 (char *)&boot_params
->eddbuf
[0] -
51 (char *)&boot_params
->_pad8
[0]);
52 memset(&boot_params
->_pad9
[0], 0, sizeof(boot_params
->_pad9
));
56 #endif /* _ASM_X86_BOOTPARAM_UTILS_H */