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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_BOOTPARAM_UTILS_H
#define _ASM_X86_BOOTPARAM_UTILS_H
#include <asm/bootparam.h>
/*
* This file is included from multiple environments. Do not
* add completing #includes to make it standalone.
*/
/*
* Deal with bootloaders which fail to initialize unknown fields in
* boot_params to zero. The list fields in this list are taken from
* analysis of kexec-tools; if other broken bootloaders initialize a
* different set of fields we will need to figure out how to disambiguate.
*
* Note: efi_info is commonly left uninitialized, but that field has a
* private magic, so it is better to leave it unchanged.
*/
static void sanitize_boot_params(struct boot_params *boot_params)
{
/*
* IMPORTANT NOTE TO BOOTLOADER AUTHORS: do not simply clear
* this field. The purpose of this field is to guarantee
* compliance with the x86 boot spec located in
* Documentation/x86/boot.txt . That spec says that the
* *whole* structure should be cleared, after which only the
* portion defined by struct setup_header (boot_params->hdr)
* should be copied in.
*
* If you're having an issue because the sentinel is set, you
* need to change the whole structure to be cleared, not this
* (or any other) individual field, or you will soon have
* problems again.
*/
if (boot_params->sentinel) {
/* fields in boot_params are left uninitialized, clear them */
memset(&boot_params->ext_ramdisk_image, 0,
(char *)&boot_params->efi_info -
(char *)&boot_params->ext_ramdisk_image);
memset(&boot_params->kbd_status, 0,
(char *)&boot_params->hdr -
(char *)&boot_params->kbd_status);
memset(&boot_params->_pad7[0], 0,
(char *)&boot_params->edd_mbr_sig_buffer[0] -
(char *)&boot_params->_pad7[0]);
memset(&boot_params->_pad8[0], 0,
(char *)&boot_params->eddbuf[0] -
(char *)&boot_params->_pad8[0]);
memset(&boot_params->_pad9[0], 0, sizeof(boot_params->_pad9));
}
}
#endif /* _ASM_X86_BOOTPARAM_UTILS_H */
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