coreboot-kgpe-d16/src/security/vboot/vbnv.h

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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2016 Google Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef __VBOOT_VBNV_H__
#define __VBOOT_VBNV_H__
#include <types.h>
/* Generic functions */
void read_vbnv(uint8_t *vbnv_copy);
void save_vbnv(const uint8_t *vbnv_copy);
int verify_vbnv(uint8_t *vbnv_copy);
vboot: Clear battery cutoff flags when vbnv_cmos loads backup VBNV. When CONFIG_VBOOT_VBNV_CMOS_BACKUP_TO_FLASH is set, vbnv_cmos will try to load VBNV from flash if the VBNV in CMOS is invalid. This is usually correct, except the case of battery cut-off. CMOS will always be invalid after battery cut-off if there is no RTC battery (or if that is dead). However, in current implementation the backup in flash is only updated in coreboot, while the real battery cutoff (and the clearing of cutoff flags in VBNV) is done in payload (Depthcharge) stage. This will create an endless reboot loop that: 1. crossystem sets battery cutoff flag in VBNV_CMOS then reboot. 2. coreboot backs-up VBNV_CMOS to VBNV_flash. 3. Depthcharge sees cutoff flag in VBNV_CMOS. 4. Depthcharge clears cutoff flag in VBNV_CMOS. 5. Depthcharge performs battery cutoff (CMOS data is lost). 6. (Plug AC adapter) Reboot. 7. Coreboot sees invalid VBNV_CMOS, load backup from VBNV_flash. 8. Jump to 3. As a result, we should always clear battery cutoff flags when loading backups from VBNV_flash. BRANCH=glados,reef BUG=chrome-os-partner:61365,chrome-os-partner:59615 TEST=emerge-reef coreboot bootimage; Change-Id: I3250a3a179a7b0de9c6e401e4a94dcd23920e473 Signed-off-by: Hung-Te Lin <hungte@chromium.org> Reviewed-on: https://chromium-review.googlesource.com/423460 Reviewed-by: Duncan Laurie <dlaurie@google.com> Reviewed-on: https://review.coreboot.org/18008 Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net> Tested-by: build bot (Jenkins) Reviewed-by: Martin Roth <martinroth@google.com>
2016-12-29 13:59:37 +01:00
void regen_vbnv_crc(uint8_t *vbnv_copy);
/* Read the USB Device Controller(UDC) enable flag from VBNV. */
int vbnv_udc_enable_flag(void);
/* Initialize and read vbnv. This is used in the main vboot logic path. */
void vbnv_init(uint8_t *vbnv_copy);
/* Reset vbnv snapshot to a known state. */
void vbnv_reset(uint8_t *vbnv_copy);
/* CMOS backend */
/* Initialize the vbnv cmos backing store. The vbnv_copy pointer is used for
optional temporary storage in the init function. */
void vbnv_init_cmos(uint8_t *vbnv_copy);
/* Return non-zero if cmos power was lost. */
int vbnv_cmos_failed(void);
void read_vbnv_cmos(uint8_t *vbnv_copy);
void save_vbnv_cmos(const uint8_t *vbnv_copy);
/* Flash backend */
void read_vbnv_flash(uint8_t *vbnv_copy);
void save_vbnv_flash(const uint8_t *vbnv_copy);
/* EC backend */
void read_vbnv_ec(uint8_t *vbnv_copy);
void save_vbnv_ec(const uint8_t *vbnv_copy);
#endif /* __VBOOT_VBNV_H__ */