0990fbf2d9
There's an occasional issue on machines which use CMOS for their vbnv storage. The machine that just powers up from complete G3 would have had their RTC rail not held up. The contents of vbnv in CMOS could pass the crc8 though the values could be bad. In order to fix this introduce two functions: 1. vbnv_init_cmos() 2. vbnv_cmos_failed() At the start of vboot the CMOS is queried for failure. If there is a failure indicated then the vbnv data is restored from flash backup or reset to known values when there is no flash backup. BUG=b:63054105 Change-Id: I8bd6f28f64a116b84a08ce4779cd4dc73c0f2f3d Signed-off-by: Aaron Durbin <adurbin@chromium.org> Reviewed-on: https://review.coreboot.org/21560 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Julius Werner <jwerner@chromium.org> Reviewed-by: Furquan Shaikh <furquan@google.com>
115 lines
3.3 KiB
C
115 lines
3.3 KiB
C
/*
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* This file is part of the coreboot project.
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*
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* Copyright (C) 2011 The ChromiumOS Authors. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <bootstate.h>
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#include <console/console.h>
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#include <types.h>
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#include <pc80/mc146818rtc.h>
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#include <vboot/vbnv.h>
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#include <vboot/vbnv_layout.h>
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static void clear_vbnv_battery_cutoff_flag(uint8_t *vbnv_copy)
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{
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/*
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* Currently battery cutoff is done in payload stage, which does not
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* update backup VBNV. And doing battery cutoff will invalidate CMOS.
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* This means for every reboot after cutoff, read_vbnv_cmos will reload
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* backup VBNV and try to cutoff again, causing endless reboot loop.
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* So we should always clear battery cutoff flag from loaded backup.
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*/
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if (vbnv_copy[MISC_FLAGS_OFFSET] & MISC_FLAGS_BATTERY_CUTOFF_MASK) {
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printk(BIOS_INFO, "VBNV: Remove battery cut-off request.\n");
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vbnv_copy[MISC_FLAGS_OFFSET] &= ~MISC_FLAGS_BATTERY_CUTOFF_MASK;
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regen_vbnv_crc(vbnv_copy);
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}
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}
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/* Return non-zero if backup was used. */
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static int restore_from_backup(uint8_t *vbnv_copy)
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{
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if (!IS_ENABLED(CONFIG_VBOOT_VBNV_CMOS_BACKUP_TO_FLASH))
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return 0;
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printk(BIOS_INFO, "VBNV: CMOS invalid, restoring from flash\n");
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read_vbnv_flash(vbnv_copy);
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if (verify_vbnv(vbnv_copy)) {
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clear_vbnv_battery_cutoff_flag(vbnv_copy);
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save_vbnv_cmos(vbnv_copy);
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printk(BIOS_INFO, "VBNV: Flash backup restored\n");
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return 1;
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}
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printk(BIOS_INFO, "VBNV: Restore from flash failed\n");
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return 0;
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}
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void read_vbnv_cmos(uint8_t *vbnv_copy)
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{
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int i;
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for (i = 0; i < VBOOT_VBNV_BLOCK_SIZE; i++)
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vbnv_copy[i] = cmos_read(CONFIG_VBOOT_VBNV_OFFSET + 14 + i);
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/* Verify contents before attempting a restore from backup storage. */
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if (verify_vbnv(vbnv_copy))
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return;
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restore_from_backup(vbnv_copy);
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}
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void save_vbnv_cmos(const uint8_t *vbnv_copy)
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{
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int i;
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for (i = 0; i < VBOOT_VBNV_BLOCK_SIZE; i++)
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cmos_write(vbnv_copy[i], CONFIG_VBOOT_VBNV_OFFSET + 14 + i);
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}
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void vbnv_init_cmos(uint8_t *vbnv_copy)
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{
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/* If no cmos failure just defer to the normal read path for checking
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vbnv contents' integrity. */
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if (!vbnv_cmos_failed())
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return;
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/* In the case of cmos failure force the backup. If backup wasn't used
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force the vbnv cmos to be reset. */
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if (!restore_from_backup(vbnv_copy)) {
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vbnv_reset(vbnv_copy);
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/* This parallels the vboot_reference implementation. */
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vbnv_copy[HEADER_OFFSET] = HEADER_SIGNATURE |
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HEADER_FIRMWARE_SETTINGS_RESET |
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HEADER_KERNEL_SETTINGS_RESET;
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regen_vbnv_crc(vbnv_copy);
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save_vbnv_cmos(vbnv_copy);
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}
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}
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#if IS_ENABLED(CONFIG_VBOOT_VBNV_CMOS_BACKUP_TO_FLASH)
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static void back_up_vbnv_cmos(void *unused)
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{
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uint8_t vbnv_cmos[VBOOT_VBNV_BLOCK_SIZE];
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/* Read current VBNV from CMOS. */
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read_vbnv_cmos(vbnv_cmos);
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/* Save to flash, will only be saved if different. */
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save_vbnv_flash(vbnv_cmos);
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}
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BOOT_STATE_INIT_ENTRY(BS_POST_DEVICE, BS_ON_EXIT, back_up_vbnv_cmos, NULL);
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#endif
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