blob: 3a9689645faa20057ea49cb2ed69ab3f14647c44 [file] [log] [blame]
/*
* This file is part of the coreboot project.
*
* Copyright (C) 2014 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.
*/
#include <compiler.h>
#include <string.h>
#include <boot_device.h>
#include <bootstate.h>
#include <bootmode.h>
#include <console/console.h>
#include <cbmem.h>
#include <elog.h>
#include <fmap.h>
#include <ip_checksum.h>
#include <region_file.h>
#include <security/vboot/vboot_common.h>
#include <spi_flash.h>
#include "mrc_cache.h"
#define DEFAULT_MRC_CACHE "RW_MRC_CACHE"
#define VARIABLE_MRC_CACHE "RW_VAR_MRC_CACHE"
#define RECOVERY_MRC_CACHE "RECOVERY_MRC_CACHE"
#define UNIFIED_MRC_CACHE "UNIFIED_MRC_CACHE"
#define MRC_DATA_SIGNATURE (('M'<<0)|('R'<<8)|('C'<<16)|('D'<<24))
struct mrc_metadata {
uint32_t signature;
uint32_t data_size;
uint16_t data_checksum;
uint16_t header_checksum;
uint32_t version;
} __packed;
enum result {
UPDATE_FAILURE = -1,
UPDATE_SUCCESS = 0,
ALREADY_UPTODATE = 1
};
#define NORMAL_FLAG (1 << 0)
#define RECOVERY_FLAG (1 << 1)
struct cache_region {
const char *name;
uint32_t cbmem_id;
int type;
int elog_slot;
int flags;
};
static const struct cache_region recovery_training = {
.name = RECOVERY_MRC_CACHE,
.cbmem_id = CBMEM_ID_MRCDATA,
.type = MRC_TRAINING_DATA,
.elog_slot = ELOG_MEM_CACHE_UPDATE_SLOT_RECOVERY,
#if IS_ENABLED(CONFIG_HAS_RECOVERY_MRC_CACHE)
.flags = RECOVERY_FLAG,
#else
.flags = 0,
#endif
};
static const struct cache_region normal_training = {
.name = DEFAULT_MRC_CACHE,
.cbmem_id = CBMEM_ID_MRCDATA,
.type = MRC_TRAINING_DATA,
.elog_slot = ELOG_MEM_CACHE_UPDATE_SLOT_NORMAL,
.flags = NORMAL_FLAG | RECOVERY_FLAG,
};
static const struct cache_region variable_data = {
.name = VARIABLE_MRC_CACHE,
.cbmem_id = CBMEM_ID_VAR_MRCDATA,
.type = MRC_VARIABLE_DATA,
.elog_slot = ELOG_MEM_CACHE_UPDATE_SLOT_VARIABLE,
.flags = NORMAL_FLAG | RECOVERY_FLAG,
};
/* Order matters here for priority in matching. */
static const struct cache_region *cache_regions[] = {
&recovery_training,
&normal_training,
&variable_data,
};
static int lookup_region_by_name(const char *name, struct region *r)
{
/* This assumes memory mapped boot media just under 4GiB. */
const uint32_t pointer_base_32bit = -CONFIG_ROM_SIZE;
if (fmap_locate_area(name, r) == 0)
return 0;
/* CHROMEOS builds must get their MRC cache from FMAP. */
if (IS_ENABLED(CONFIG_CHROMEOS)) {
printk(BIOS_ERR, "MRC: Chrome OS lookup failure.\n");
return -1;
}
if (!IS_ENABLED(CONFIG_BOOT_DEVICE_MEMORY_MAPPED))
return -1;
/* Base is in the form of a pointer. Make it an offset. */
r->offset = CONFIG_MRC_SETTINGS_CACHE_BASE - pointer_base_32bit;
r->size = CONFIG_MRC_SETTINGS_CACHE_SIZE;
return 0;
}
static const struct cache_region *lookup_region_type(int type)
{
int i;
int flags;
if (vboot_recovery_mode_enabled())
flags = RECOVERY_FLAG;
else
flags = NORMAL_FLAG;
for (i = 0; i < ARRAY_SIZE(cache_regions); i++) {
if (cache_regions[i]->type != type)
continue;
if ((cache_regions[i]->flags & flags) == flags)
return cache_regions[i];
}
return NULL;
}
int mrc_cache_stash_data(int type, uint32_t version, const void *data,
size_t size)
{
const struct cache_region *cr;
size_t cbmem_size;
struct mrc_metadata *md;
cr = lookup_region_type(type);
if (cr == NULL) {
printk(BIOS_ERR, "MRC: failed to add to cbmem for type %d.\n",
type);
return -1;
}
cbmem_size = sizeof(*md) + size;
md = cbmem_add(cr->cbmem_id, cbmem_size);
if (md == NULL) {
printk(BIOS_ERR, "MRC: failed to add '%s' to cbmem.\n",
cr->name);
return -1;
}
memset(md, 0, sizeof(*md));
md->signature = MRC_DATA_SIGNATURE;
md->data_size = size;
md->version = version;
md->data_checksum = compute_ip_checksum(data, size);
md->header_checksum = compute_ip_checksum(md, sizeof(*md));
memcpy(&md[1], data, size);
return 0;
}
static const struct cache_region *lookup_region(struct region *r, int type)
{
const struct cache_region *cr;
cr = lookup_region_type(type);
if (cr == NULL) {
printk(BIOS_ERR, "MRC: failed to locate region type %d.\n",
type);
return NULL;
}
if (lookup_region_by_name(cr->name, r) < 0)
return NULL;
return cr;
}
static int mrc_header_valid(struct region_device *rdev, struct mrc_metadata *md)
{
uint16_t checksum;
uint16_t checksum_result;
size_t size;
if (rdev_readat(rdev, md, 0, sizeof(*md)) < 0) {
printk(BIOS_ERR, "MRC: couldn't read metadata\n");
return -1;
}
if (md->signature != MRC_DATA_SIGNATURE) {
printk(BIOS_ERR, "MRC: invalid header signature\n");
return -1;
}
/* Compute checksum over header with 0 as the value. */
checksum = md->header_checksum;
md->header_checksum = 0;
checksum_result = compute_ip_checksum(md, sizeof(*md));
if (checksum != checksum_result) {
printk(BIOS_ERR, "MRC: header checksum mismatch: %x vs %x\n",
checksum, checksum_result);
return -1;
}
/* Put back original. */
md->header_checksum = checksum;
/* Re-size the region device according to the metadata as a region_file
* does block allocation. */
size = sizeof(*md) + md->data_size;
if (rdev_chain(rdev, rdev, 0, size) < 0) {
printk(BIOS_ERR, "MRC: size exceeds rdev size: %zx vs %zx\n",
size, region_device_sz(rdev));
return -1;
}
return 0;
}
static int mrc_data_valid(const struct region_device *rdev,
const struct mrc_metadata *md)
{
void *data;
uint16_t checksum;
const size_t md_size = sizeof(*md);
const size_t data_size = md->data_size;
data = rdev_mmap(rdev, md_size, data_size);
if (data == NULL) {
printk(BIOS_ERR, "MRC: mmap failure on data verification.\n");
return -1;
}
checksum = compute_ip_checksum(data, data_size);
rdev_munmap(rdev, data);
if (md->data_checksum != checksum) {
printk(BIOS_ERR, "MRC: data checksum mismatch: %x vs %x\n",
md->data_checksum, checksum);
return -1;
}
return 0;
}
static int mrc_cache_latest(const char *name,
const struct region_device *backing_rdev,
struct mrc_metadata *md,
struct region_file *cache_file,
struct region_device *rdev,
bool fail_bad_data)
{
/* Init and obtain a handle to the file data. */
if (region_file_init(cache_file, backing_rdev) < 0) {
printk(BIOS_ERR, "MRC: region file invalid in '%s'\n", name);
return -1;
}
/* Provide a 0 sized region_device from here on out so the caller
* has a valid yet unusable region_device. */
rdev_chain(rdev, backing_rdev, 0, 0);
/* No data to return. */
if (region_file_data(cache_file, rdev) < 0) {
printk(BIOS_ERR, "MRC: no data in '%s'\n", name);
return fail_bad_data ? -1 : 0;
}
/* Validate header and resize region to reflect actual usage on the
* saved medium (including metadata and data). */
if (mrc_header_valid(rdev, md) < 0) {
printk(BIOS_ERR, "MRC: invalid header in '%s'\n", name);
return fail_bad_data ? -1 : 0;
}
/* Validate Data */
if (mrc_data_valid(rdev, md) < 0) {
printk(BIOS_ERR, "MRC: invalid data in '%s'\n", name);
return fail_bad_data ? -1 : 0;
}
return 0;
}
int mrc_cache_get_current(int type, uint32_t version,
struct region_device *rdev)
{
const struct cache_region *cr;
struct region region;
struct region_device read_rdev;
struct region_file cache_file;
struct mrc_metadata md;
size_t data_size;
const size_t md_size = sizeof(md);
const bool fail_bad_data = true;
cr = lookup_region(&region, type);
if (cr == NULL)
return -1;
if (boot_device_ro_subregion(&region, &read_rdev) < 0)
return -1;
if (mrc_cache_latest(cr->name, &read_rdev, &md, &cache_file, rdev,
fail_bad_data) < 0)
return -1;
if (version != md.version) {
printk(BIOS_INFO, "MRC: version mismatch: %x vs %x\n",
md.version, version);
return -1;
}
/* Re-size rdev to only contain the data. i.e. remove metadata. */
data_size = md.data_size;
return rdev_chain(rdev, rdev, md_size, data_size);
}
static bool mrc_cache_needs_update(const struct region_device *rdev,
const struct cbmem_entry *to_be_updated)
{
void *mapping;
size_t size = region_device_sz(rdev);
bool need_update = false;
if (cbmem_entry_size(to_be_updated) != size)
return true;
mapping = rdev_mmap_full(rdev);
if (memcmp(cbmem_entry_start(to_be_updated), mapping, size))
need_update = true;
rdev_munmap(rdev, mapping);
return need_update;
}
static void log_event_cache_update(uint8_t slot, enum result res)
{
const int type = ELOG_TYPE_MEM_CACHE_UPDATE;
struct elog_event_mem_cache_update event = {
.slot = slot
};
/* Filter through interesting events only */
switch (res) {
case UPDATE_FAILURE:
event.status = ELOG_MEM_CACHE_UPDATE_STATUS_FAIL;
break;
case UPDATE_SUCCESS:
event.status = ELOG_MEM_CACHE_UPDATE_STATUS_SUCCESS;
break;
default:
return;
}
if (elog_add_event_raw(type, &event, sizeof(event)) < 0)
printk(BIOS_ERR, "Failed to log mem cache update event.\n");
}
/* During ramstage this code purposefully uses incoherent transactions between
* read and write. The read assumes a memory-mapped boot device that can be used
* to quickly locate and compare the up-to-date data. However, when an update
* is required it uses the writeable region access to perform the update. */
static void update_mrc_cache_by_type(int type)
{
const struct cache_region *cr;
struct region region;
struct region_device read_rdev;
struct region_device write_rdev;
struct region_file cache_file;
struct mrc_metadata md;
const struct cbmem_entry *to_be_updated;
struct incoherent_rdev backing_irdev;
const struct region_device *backing_rdev;
struct region_device latest_rdev;
const bool fail_bad_data = false;
cr = lookup_region(&region, type);
if (cr == NULL)
return;
to_be_updated = cbmem_entry_find(cr->cbmem_id);
if (to_be_updated == NULL) {
printk(BIOS_ERR, "MRC: No data in cbmem for '%s'.\n",
cr->name);
return;
}
printk(BIOS_DEBUG, "MRC: Checking cached data update for '%s'.\n",
cr->name);
if (boot_device_ro_subregion(&region, &read_rdev) < 0)
return;
if (boot_device_rw_subregion(&region, &write_rdev) < 0)
return;
backing_rdev = incoherent_rdev_init(&backing_irdev, &region, &read_rdev,
&write_rdev);
if (backing_rdev == NULL)
return;
if (mrc_cache_latest(cr->name, backing_rdev, &md, &cache_file,
&latest_rdev, fail_bad_data) < 0)
return;
if (!mrc_cache_needs_update(&latest_rdev, to_be_updated)) {
log_event_cache_update(cr->elog_slot, ALREADY_UPTODATE);
return;
}
printk(BIOS_DEBUG, "MRC: cache data '%s' needs update.\n", cr->name);
if (region_file_update_data(&cache_file,
cbmem_entry_start(to_be_updated),
cbmem_entry_size(to_be_updated)) < 0)
log_event_cache_update(cr->elog_slot, UPDATE_FAILURE);
else
log_event_cache_update(cr->elog_slot, UPDATE_SUCCESS);
}
/* Read flash status register to determine if write protect is active */
static int nvm_is_write_protected(void)
{
u8 sr1;
u8 wp_gpio;
u8 wp_spi;
if (!IS_ENABLED(CONFIG_CHROMEOS))
return 0;
if (!IS_ENABLED(CONFIG_BOOT_DEVICE_SPI_FLASH))
return 0;
/* Read Write Protect GPIO if available */
wp_gpio = get_write_protect_state();
/* Read Status Register 1 */
if (spi_flash_status(boot_device_spi_flash(), &sr1) < 0) {
printk(BIOS_ERR, "Failed to read SPI status register 1\n");
return -1;
}
wp_spi = !!(sr1 & 0x80);
printk(BIOS_DEBUG, "SPI flash protection: WPSW=%d SRP0=%d\n",
wp_gpio, wp_spi);
return wp_gpio && wp_spi;
}
/* Apply protection to a range of flash */
static int nvm_protect(const struct region *r)
{
if (!IS_ENABLED(CONFIG_MRC_SETTINGS_PROTECT))
return 0;
if (!IS_ENABLED(CONFIG_BOOT_DEVICE_SPI_FLASH))
return 0;
return spi_flash_ctrlr_protect_region(boot_device_spi_flash(), r);
}
/* Protect mrc region with a Protected Range Register */
static int protect_mrc_cache(const char *name)
{
struct region region;
if (!IS_ENABLED(CONFIG_MRC_SETTINGS_PROTECT))
return 0;
if (lookup_region_by_name(name, &region) < 0) {
printk(BIOS_ERR, "MRC: Could not find region '%s'\n", name);
return -1;
}
if (nvm_is_write_protected() <= 0) {
printk(BIOS_INFO, "MRC: NOT enabling PRR for '%s'.\n", name);
return 0;
}
if (nvm_protect(&region) < 0) {
printk(BIOS_ERR, "MRC: ERROR setting PRR for '%s'.\n", name);
return -1;
}
printk(BIOS_INFO, "MRC: Enabled Protected Range on '%s'.\n", name);
return 0;
}
static void protect_mrc_region(void)
{
/*
* Check if there is a single unified region that encompasses both
* RECOVERY_MRC_CACHE and DEFAULT_MRC_CACHE. In that case protect the
* entire region using a single PRR.
*
* If we are not able to protect the entire region, try protecting
* individual regions next.
*/
if (protect_mrc_cache(UNIFIED_MRC_CACHE) == 0)
return;
if (IS_ENABLED(CONFIG_HAS_RECOVERY_MRC_CACHE))
protect_mrc_cache(RECOVERY_MRC_CACHE);
protect_mrc_cache(DEFAULT_MRC_CACHE);
}
static void invalidate_normal_cache(void)
{
struct region_file cache_file;
struct region_device rdev;
const char *name = DEFAULT_MRC_CACHE;
const uint32_t invalid = ~MRC_DATA_SIGNATURE;
/* Invalidate only on recovery mode with retraining enabled. */
if (!vboot_recovery_mode_enabled())
return;
if (!vboot_recovery_mode_memory_retrain())
return;
if (fmap_locate_area_as_rdev_rw(name, &rdev) < 0) {
printk(BIOS_ERR, "MRC: Couldn't find '%s' region. Invalidation failed\n",
name);
return;
}
if (region_file_init(&cache_file, &rdev) < 0) {
printk(BIOS_ERR, "MRC: region file invalid for '%s'. Invalidation failed\n",
name);
return;
}
/* Push an update that consists of 4 bytes that is smaller than the
* MRC metadata as well as an invalid signature. */
if (region_file_update_data(&cache_file, &invalid, sizeof(invalid)) < 0)
printk(BIOS_ERR, "MRC: invalidation failed for '%s'.\n", name);
}
static void update_mrc_cache(void *unused)
{
update_mrc_cache_by_type(MRC_TRAINING_DATA);
if (IS_ENABLED(CONFIG_MRC_SETTINGS_VARIABLE_DATA))
update_mrc_cache_by_type(MRC_VARIABLE_DATA);
if (IS_ENABLED(CONFIG_MRC_CLEAR_NORMAL_CACHE_ON_RECOVERY_RETRAIN))
invalidate_normal_cache();
protect_mrc_region();
}
/*
* Ensures MRC training data is stored into SPI after PCI enumeration is done
* during BS_DEV_ENUMERATE-BS_ON_EXIT and lock down SPI protected ranges
* during BS_DEV_RESOURCES-BS_ON_EXIT.
*/
BOOT_STATE_INIT_ENTRY(BS_DEV_ENUMERATE, BS_ON_EXIT, update_mrc_cache, NULL);