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3c4aff6b9a
If the sentinel triggers, we do not want the boot loader authors to just poke it and make the error go away, we want them to actually fix the problem. This should help avoid making the incorrect change in non-compliant bootloaders. [ hpa: dropped the Documentation/x86/boot.txt hunk pending clarifications ] Signed-off-by: Peter Jones <pjones@redhat.com> Link: http://lkml.kernel.org/r/1362592823-28967-1-git-send-email-pjones@redhat.com Signed-off-by: H. Peter Anvin <hpa@zytor.com>
54 lines
2 KiB
C
54 lines
2 KiB
C
#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->olpc_ofw_header, 0,
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(char *)&boot_params->efi_info -
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(char *)&boot_params->olpc_ofw_header);
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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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