linux_dsm_epyc7002/arch/x86/include/asm/bootparam_utils.h
Juergen Gross 182ddd1619 x86/boot: Clear RSDP address in boot_params for broken loaders
Gunnar Krueger reported a systemd-boot failure and bisected it down to:

  e6e094e053 ("x86/acpi, x86/boot: Take RSDP address from boot params if available")

In case a broken boot loader doesn't clear its 'struct boot_params', clear
rsdp_addr in sanitize_boot_params().

Reported-by: Gunnar Krueger <taijian@posteo.de>
Tested-by: Gunnar Krueger <taijian@posteo.de>
Signed-off-by: Juergen Gross <jgross@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bp@alien8.de
Cc: sstabellini@kernel.org
Fixes: e6e094e053 ("x86/acpi, x86/boot: Take RSDP address from boot params if available")
Link: http://lkml.kernel.org/r/20181203103811.17056-1-jgross@suse.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-12-03 11:56:37 +01:00

57 lines
2.0 KiB
C

/* 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 */
boot_params->acpi_rsdp_addr = 0;
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 */