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