[RFC PATCH 04/10] FWU: Add metadata access functions for GPT partitioned block devices

Sughosh Ganu sughosh.ganu at linaro.org
Thu Nov 25 08:01:40 CET 2021


In the FWU Multi Bank Update feature, the information about the
updatable images is stored as part of the metadata, on a separate
partition. Add functions for reading from and writing to the metadata
when the updatable images and the metadata are stored on a block
device which is formated with GPT based partition scheme.

Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
---
 lib/fwu_updates/fwu_metadata_gpt_blk.c | 716 +++++++++++++++++++++++++
 1 file changed, 716 insertions(+)
 create mode 100644 lib/fwu_updates/fwu_metadata_gpt_blk.c

diff --git a/lib/fwu_updates/fwu_metadata_gpt_blk.c b/lib/fwu_updates/fwu_metadata_gpt_blk.c
new file mode 100644
index 0000000000..98cc53f706
--- /dev/null
+++ b/lib/fwu_updates/fwu_metadata_gpt_blk.c
@@ -0,0 +1,716 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2021, Linaro Limited
+ */
+
+#include <blk.h>
+#include <efi_loader.h>
+#include <fwu_metadata.h>
+#include <malloc.h>
+#include <memalign.h>
+#include <part.h>
+#include <part_efi.h>
+
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <u-boot/crc.h>
+
+#define PRIMARY_VALID		0x1
+#define SECONDARY_VALID		0x2
+
+#define MDATA_READ		(u8)0x1
+#define MDATA_WRITE		(u8)0x2
+
+#define IMAGE_ACCEPT_SET	(u8)0x1
+#define IMAGE_ACCEPT_CLEAR	(u8)0x2
+
+static int gpt_verify_metadata(struct fwu_metadata *metadata, bool pri_part)
+{
+	u32 calc_crc32;
+	void *buf;
+
+	buf = &metadata->version;
+	calc_crc32 = crc32(0, buf, sizeof(*metadata) - sizeof(u32));
+
+	if (calc_crc32 != metadata->crc32) {
+		log_err("crc32 check failed for %s metadata partition\n",
+			pri_part ? "primary" : "secondary");
+		return -1;
+	}
+
+	return 0;
+}
+
+static int gpt_get_metadata_partitions(struct blk_desc *desc,
+				       u32 *primary_mpart,
+				       u32 *secondary_mpart)
+{
+	int i, ret;
+	u32 nparts, mparts;
+	gpt_entry *gpt_pte = NULL;
+	const efi_guid_t fwu_metadata_guid = FWU_METADATA_GUID;
+
+	ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_head, 1,
+				     desc->blksz);
+
+	ret = get_gpt_hdr_parts(desc, gpt_head, &gpt_pte);
+	if (ret < 0) {
+		log_err("Error getting GPT header and partitions\n");
+		ret = -EIO;
+		goto out;
+	}
+
+	nparts = gpt_head->num_partition_entries;
+	for (i = 0, mparts = 0; i < nparts; i++) {
+		if (!guidcmp(&fwu_metadata_guid,
+			     &gpt_pte[i].partition_type_guid)) {
+			++mparts;
+			if (!*primary_mpart)
+				*primary_mpart = i + 1;
+			else
+				*secondary_mpart = i + 1;
+		}
+	}
+
+	if (mparts != 2) {
+		log_err("Expect two copies of the metadata instead of %d\n",
+			mparts);
+		ret = -EINVAL;
+	} else {
+		ret = 0;
+	}
+out:
+	free(gpt_pte);
+
+	return ret;
+}
+
+static int gpt_get_metadata_disk_part(struct blk_desc *desc,
+				      struct disk_partition *info,
+				      u32 part_num)
+{
+	int ret;
+	char *metadata_guid_str = "8a7a84a0-8387-40f6-ab41-a8b9a5a60d23";
+
+	ret = part_get_info(desc, part_num, info);
+	if (ret < 0) {
+		log_err("Unable to get the partition info for the metadata part %d",
+			part_num);
+		return -1;
+	}
+
+	/* Check that it is indeed the metadata partition */
+	if (!strncmp(info->type_guid, metadata_guid_str, UUID_STR_LEN)) {
+		/* Found the metadata partition */
+		return 0;
+	}
+
+	return -1;
+}
+
+static int gpt_read_write_metadata(struct blk_desc *desc,
+				   struct fwu_metadata *metadata,
+				   u8 access, u32 part_num)
+{
+	int ret;
+	u32 len, blk_start, blkcnt;
+	struct disk_partition info;
+
+	ALLOC_CACHE_ALIGN_BUFFER_PAD(struct fwu_metadata, mdata, 1, desc->blksz);
+
+	ret = gpt_get_metadata_disk_part(desc, &info, part_num);
+	if (ret < 0) {
+		printf("Unable to get the metadata partition\n");
+		return -ENODEV;
+	}
+
+	len = sizeof(*metadata);
+	blkcnt = BLOCK_CNT(len, desc);
+	if (blkcnt > info.size) {
+		log_err("Block count exceeds metadata partition size\n");
+		return -ERANGE;
+	}
+
+	blk_start = info.start;
+	if (access == MDATA_READ) {
+		if (blk_dread(desc, blk_start, blkcnt, mdata) != blkcnt) {
+			log_err("Error reading metadata from the device\n");
+			return -EIO;
+		}
+		memcpy(metadata, mdata, sizeof(struct fwu_metadata));
+	} else {
+		if (blk_dwrite(desc, blk_start, blkcnt, metadata) != blkcnt) {
+			log_err("Error writing metadata to the device\n");
+			return -EIO;
+		}
+	}
+
+	return 0;
+}
+
+static int gpt_read_metadata(struct blk_desc *desc,
+			     struct fwu_metadata *metadata, u32 part_num)
+{
+	return gpt_read_write_metadata(desc, metadata, MDATA_READ, part_num);
+}
+
+static int gpt_write_metadata_partition(struct blk_desc *desc,
+					struct fwu_metadata *metadata,
+					u32 part_num)
+{
+	return gpt_read_write_metadata(desc, metadata, MDATA_WRITE, part_num);
+}
+
+static int gpt_update_metadata(struct fwu_metadata *metadata)
+{
+	int ret;
+	struct blk_desc *desc;
+	u32 primary_mpart, secondary_mpart;
+
+	ret = fwu_plat_get_blk_desc(&desc);
+	if (ret < 0) {
+		log_err("Block device not found\n");
+		return -ENODEV;
+	}
+
+	primary_mpart = secondary_mpart = 0;
+	ret = gpt_get_metadata_partitions(desc, &primary_mpart,
+					  &secondary_mpart);
+
+	if (ret < 0) {
+		log_err("Error getting the metadata partitions\n");
+		return -ENODEV;
+	}
+
+	/* First write the primary partition*/
+	ret = gpt_write_metadata_partition(desc, metadata, primary_mpart);
+	if (ret < 0) {
+		log_err("Updating primary metadata partition failed\n");
+		return ret;
+	}
+
+	/* And now the replica */
+	ret = gpt_write_metadata_partition(desc, metadata, secondary_mpart);
+	if (ret < 0) {
+		log_err("Updating secondary metadata partition failed\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int gpt_get_valid_metadata(struct fwu_metadata **metadata)
+{
+	int ret;
+	struct blk_desc *desc;
+	u32 primary_mpart, secondary_mpart;
+
+	ret = fwu_plat_get_blk_desc(&desc);
+	if (ret < 0) {
+		log_err("Block device not found\n");
+		return -ENODEV;
+	}
+
+	primary_mpart = secondary_mpart = 0;
+	ret = gpt_get_metadata_partitions(desc, &primary_mpart,
+					  &secondary_mpart);
+
+	if (ret < 0) {
+		log_err("Error getting the metadata partitions\n");
+		return -ENODEV;
+	}
+
+	*metadata = malloc(sizeof(struct fwu_metadata));
+	if (!*metadata) {
+		log_err("Unable to allocate memory for reading metadata\n");
+		return -ENOMEM;
+	}
+
+	ret = gpt_read_metadata(desc, *metadata, primary_mpart);
+	if (ret < 0) {
+		log_err("Failed to read the metadata from the device\n");
+		return -EIO;
+	}
+
+	ret = gpt_verify_metadata(*metadata, 1);
+	if (!ret)
+		return 0;
+
+	/*
+	 * Verification of the primary metadata copy failed.
+	 * Try to read the replica.
+	 */
+	memset(*metadata, 0, sizeof(struct fwu_metadata));
+	ret = gpt_read_metadata(desc, *metadata, secondary_mpart);
+	if (ret < 0) {
+		log_err("Failed to read the metadata from the device\n");
+		return -EIO;
+	}
+
+	ret = gpt_verify_metadata(*metadata, 0);
+	if (!ret)
+		return 0;
+
+	/* Both the metadata copies are corrupted. */
+	return -1;
+}
+
+static int gpt_check_metadata_validity(void)
+{
+	int ret;
+	struct blk_desc *desc;
+	struct fwu_metadata *pri_metadata;
+	struct fwu_metadata *secondary_metadata;
+	u32 primary_mpart, secondary_mpart;
+	u32 valid_partitions;
+
+	ret = fwu_plat_get_blk_desc(&desc);
+	if (ret < 0) {
+		log_err("Block device not found\n");
+		return -ENODEV;
+	}
+
+	/*
+	 * Two metadata partitions are expected.
+	 * If we don't have two, user needs to create
+	 * them first
+	 */
+	primary_mpart = secondary_mpart = 0;
+	valid_partitions = 0;
+	ret = gpt_get_metadata_partitions(desc, &primary_mpart,
+					  &secondary_mpart);
+
+	if (ret < 0) {
+		log_err("Error getting the metadata partitions\n");
+		return -ENODEV;
+	}
+
+	pri_metadata = malloc(sizeof(*pri_metadata));
+	if (!pri_metadata) {
+		log_err("Unable to allocate memory for reading metadata\n");
+		return -ENOMEM;
+	}
+
+	secondary_metadata = malloc(sizeof(*secondary_metadata));
+	if (!secondary_metadata) {
+		log_err("Unable to allocate memory for reading metadata\n");
+		return -ENOMEM;
+	}
+
+	ret = gpt_read_metadata(desc, pri_metadata, primary_mpart);
+	if (ret < 0) {
+		log_err("Failed to read the metadata from the device\n");
+		ret = -EIO;
+		goto out;
+	}
+
+	ret = gpt_verify_metadata(pri_metadata, 1);
+	if (!ret)
+		valid_partitions |= PRIMARY_VALID;
+
+	/* Now check the secondary partition */
+	ret = gpt_read_metadata(desc, secondary_metadata, secondary_mpart);
+	if (ret < 0) {
+		log_err("Failed to read the metadata from the device\n");
+		ret = -EIO;
+		goto out;
+	}
+
+	ret = gpt_verify_metadata(secondary_metadata, 0);
+	if (!ret)
+		valid_partitions |= SECONDARY_VALID;
+
+	if (valid_partitions == (PRIMARY_VALID | SECONDARY_VALID)) {
+		ret = -1;
+		/*
+		 * Before returning, check that both the
+		 * metadata copies are the same. If not,
+		 * the metadata copies need to be
+		 * re-populated.
+		 */
+		if (!memcmp(pri_metadata, secondary_metadata,
+			    sizeof(*pri_metadata)))
+			ret = 0;
+		goto out;
+	} else if (valid_partitions == SECONDARY_VALID) {
+		ret = gpt_write_metadata_partition(desc, secondary_metadata,
+						   primary_mpart);
+		if (ret < 0) {
+			log_err("Restoring primary metadata partition failed\n");
+			goto out;
+		}
+	} else if (valid_partitions == PRIMARY_VALID) {
+		ret = gpt_write_metadata_partition(desc, pri_metadata,
+						   secondary_mpart);
+		if (ret < 0) {
+			log_err("Restoring secondary metadata partition failed\n");
+			goto out;
+		}
+	} else {
+		ret = -1;
+	}
+
+out:
+	free(pri_metadata);
+
+	return ret;
+}
+
+static int gpt_fill_partition_guid_array(struct blk_desc *desc,
+					 efi_guid_t **part_guid_arr,
+					 u32 *nparts)
+{
+	int ret, i;
+	u32 parts;
+	gpt_entry *gpt_pte = NULL;
+	const efi_guid_t null_guid = NULL_GUID;
+
+	ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_head, 1,
+				     desc->blksz);
+
+	ret = get_gpt_hdr_parts(desc, gpt_head, &gpt_pte);
+	if (ret < 0) {
+		log_err("Error getting GPT header and partitions\n");
+		ret = -EIO;
+		goto out;
+	}
+
+	*nparts = gpt_head->num_partition_entries;
+
+	/*
+	 * There could be a scenario where the number of partition entries
+	 * configured in the GPT header is the default value of 128. Find
+	 * the actual number of populated partitioned entries
+	 */
+	for (i = 0, parts = 0; i < *nparts; i++) {
+		if (!guidcmp(&gpt_pte[i].partition_type_guid, &null_guid))
+			continue;
+		++parts;
+	}
+
+	*nparts = parts;
+	*part_guid_arr = malloc(sizeof(efi_guid_t) * *nparts);
+	if (!part_guid_arr) {
+		log_err("Unable to allocate memory for guid array\n");
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	for (i = 0; i < *nparts; i++) {
+		guidcpy((*part_guid_arr + i),
+			&gpt_pte[i].partition_type_guid);
+	}
+
+out:
+	free(gpt_pte);
+	return ret;
+}
+
+int fwu_gpt_get_active_index(u32 *active_idx)
+{
+	int ret;
+	struct fwu_metadata *metadata;
+
+	ret = gpt_get_valid_metadata(&metadata);
+	if (ret < 0) {
+		log_err("Unable to get valid metadata\n");
+		goto out;
+	}
+
+	/*
+	 * Found the metadata partition, now read the active_index
+	 * value
+	 */
+	*active_idx = metadata->active_index;
+	if (*active_idx > CONFIG_FWU_NUM_BANKS - 1) {
+		printf("Active index value read is incorrect\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+out:
+	free(metadata);
+
+	return ret;
+}
+
+static int gpt_get_image_alt_num(struct blk_desc *desc,
+				 efi_guid_t image_type_id,
+				 u32 update_bank, int *alt_no)
+{
+	int ret, i;
+	u32 nparts;
+	gpt_entry *gpt_pte = NULL;
+	struct fwu_metadata *metadata;
+	struct fwu_image_entry *img_entry;
+	struct fwu_image_bank_info *img_bank_info;
+	efi_guid_t unique_part_guid;
+	efi_guid_t image_guid = NULL_GUID;
+
+	ALLOC_CACHE_ALIGN_BUFFER_PAD(gpt_header, gpt_head, 1,
+				     desc->blksz);
+
+	ret = gpt_get_valid_metadata(&metadata);
+	if (ret < 0) {
+		log_err("Unable to read valid metadata\n");
+		goto out;
+	}
+
+	/*
+	 * The metadata has been read. Now get the image_uuid for the
+	 * image with the update_bank.
+	 */
+	for (i = 0; i < CONFIG_FWU_NUM_IMAGES_PER_BANK; i++) {
+		if (!guidcmp(&image_type_id,
+			     &metadata->img_entry[i].image_type_uuid)) {
+			img_entry = &metadata->img_entry[i];
+			img_bank_info = &img_entry->img_bank_info[update_bank];
+			guidcpy(&image_guid, &img_bank_info->image_uuid);
+		}
+	}
+
+	/*
+	 * Now read the GPT Partition Table Entries to find a matching
+	 * partition with UniquePartitionGuid value. We need to iterate
+	 * through all the GPT partitions since they might be in any
+	 * order
+	 */
+	ret = get_gpt_hdr_parts(desc, gpt_head, &gpt_pte);
+	if (ret < 0) {
+		log_err("Error getting GPT header and partitions\n");
+		ret = -EIO;
+		goto out;
+	}
+
+	nparts = gpt_head->num_partition_entries;
+
+	for (i = 0; i < nparts; i++) {
+		unique_part_guid = gpt_pte[i].unique_partition_guid;
+		if (!guidcmp(&unique_part_guid, &image_guid)) {
+			/* Found the partition */
+			*alt_no = i + 1;
+			break;
+		}
+	}
+
+	if (i == nparts) {
+		log_err("Partition with the image guid not found\n");
+		ret = -EINVAL;
+	}
+
+out:
+	free(metadata);
+	free(gpt_pte);
+	return ret;
+}
+
+int fwu_gpt_update_active_index(u32 active_idx)
+{
+	int ret;
+	void *buf;
+	u32 cur_active_index;
+	struct fwu_metadata *metadata;
+
+	if (active_idx > CONFIG_FWU_NUM_BANKS) {
+		printf("Active index value to be updated is incorrect\n");
+		return -1;
+	}
+
+	ret = gpt_get_valid_metadata(&metadata);
+	if (ret < 0) {
+		log_err("Unable to get valid metadata\n");
+		goto out;
+	}
+
+	/*
+	 * Update the active index and previous_active_index fields
+	 * in the metadata
+	 */
+	cur_active_index = metadata->active_index;
+	metadata->active_index = active_idx;
+	metadata->previous_active_index = cur_active_index;
+
+	/*
+	 * Calculate the crc32 for the updated metadata
+	 * and put the updated value in the metadata crc32
+	 * field
+	 */
+	buf = &metadata->version;
+	metadata->crc32 = crc32(0, buf, sizeof(*metadata) - sizeof(u32));
+
+	/*
+	 * Now write this updated metadata to both the
+	 * metadata partitions
+	 */
+	ret = gpt_update_metadata(metadata);
+	if (ret < 0) {
+		log_err("Failed to update metadata partitions\n");
+		ret = -EIO;
+	}
+
+out:
+	free(metadata);
+
+	return ret;
+}
+
+int fwu_gpt_fill_partition_guid_array(efi_guid_t **part_guid_arr, u32 *nparts)
+{
+	int ret;
+	struct blk_desc *desc;
+
+	ret = fwu_plat_get_blk_desc(&desc);
+	if (ret < 0) {
+		log_err("Block device not found\n");
+		return -ENODEV;
+	}
+
+	return gpt_fill_partition_guid_array(desc, part_guid_arr, nparts);
+}
+
+int fwu_gpt_get_image_alt_num(efi_guid_t image_type_id, u32 update_bank,
+			      int *alt_no)
+{
+	int ret;
+	struct blk_desc *desc;
+
+	ret = fwu_plat_get_blk_desc(&desc);
+	if (ret < 0) {
+		log_err("Block device not found\n");
+		return -ENODEV;
+	}
+
+	return gpt_get_image_alt_num(desc, image_type_id, update_bank, alt_no);
+}
+
+int fwu_gpt_metadata_check(void)
+{
+	/*
+	 * Check if both the copies of the metadata are valid.
+	 * If one has gone bad, restore it from the other good
+	 * copy.
+	 */
+	return gpt_check_metadata_validity();
+}
+
+int fwu_gpt_get_metadata(struct fwu_metadata **metadata)
+{
+	return gpt_get_valid_metadata(metadata);
+}
+
+int fwu_gpt_revert_boot_index(u32 *active_idx)
+{
+	int ret;
+	void *buf;
+	u32 cur_active_index;
+	struct fwu_metadata *metadata;
+
+	ret = gpt_get_valid_metadata(&metadata);
+	if (ret < 0) {
+		log_err("Unable to get valid metadata\n");
+		goto out;
+	}
+
+	/*
+	 * Swap the active index and previous_active_index fields
+	 * in the metadata
+	 */
+	cur_active_index = metadata->active_index;
+	metadata->active_index = metadata->previous_active_index;
+	metadata->previous_active_index = cur_active_index;
+	*active_idx = metadata->active_index;
+
+	/*
+	 * Calculate the crc32 for the updated metadata
+	 * and put the updated value in the metadata crc32
+	 * field
+	 */
+	buf = &metadata->version;
+	metadata->crc32 = crc32(0, buf, sizeof(*metadata) - sizeof(u32));
+
+	/*
+	 * Now write this updated metadata to both the
+	 * metadata partitions
+	 */
+	ret = gpt_update_metadata(metadata);
+	if (ret < 0) {
+		log_err("Failed to update metadata partitions\n");
+		ret = -EIO;
+	}
+
+out:
+	free(metadata);
+
+	return ret;
+}
+
+static int fwu_gpt_set_clear_image_accept(efi_guid_t *img_type_id,
+					  u32 bank, u8 action)
+{
+	void *buf;
+	int ret, i;
+	u32 nimages;
+	struct fwu_metadata *metadata;
+	struct fwu_image_entry *img_entry;
+	struct fwu_image_bank_info *img_bank_info;
+
+	ret = gpt_get_valid_metadata(&metadata);
+	if (ret < 0) {
+		log_err("Unable to get valid metadata\n");
+		goto out;
+	}
+
+	if (action == IMAGE_ACCEPT_SET)
+		bank = metadata->active_index;
+
+	nimages = CONFIG_FWU_NUM_IMAGES_PER_BANK;
+	img_entry = &metadata->img_entry[0];
+	for (i = 0; i < nimages; i++) {
+		if (!guidcmp(&img_entry[i].image_type_uuid, img_type_id)) {
+			img_bank_info = &img_entry[i].img_bank_info[bank];
+			if (action == IMAGE_ACCEPT_SET)
+				img_bank_info->accepted |= FWU_IMAGE_ACCEPTED;
+			else
+				img_bank_info->accepted = 0;
+
+			buf = &metadata->version;
+			metadata->crc32 = crc32(0, buf, sizeof(*metadata) -
+						sizeof(u32));
+
+			ret = gpt_update_metadata(metadata);
+			goto out;
+		}
+	}
+
+	/* Image not found */
+	ret = -EINVAL;
+
+out:
+	free(metadata);
+
+	return ret;
+}
+
+int fwu_gpt_accept_image(efi_guid_t *img_type_id)
+{
+	return fwu_gpt_set_clear_image_accept(img_type_id, 0,
+					      IMAGE_ACCEPT_SET);
+}
+
+int fwu_gpt_clear_accept_image(efi_guid_t *img_type_id, u32 bank)
+{
+	return fwu_gpt_set_clear_image_accept(img_type_id, bank,
+					      IMAGE_ACCEPT_CLEAR);
+}
+
+struct fwu_metadata_ops fwu_gpt_blk_ops = {
+	.get_active_index = fwu_gpt_get_active_index,
+	.update_active_index = fwu_gpt_update_active_index,
+	.fill_partition_guid_array = fwu_gpt_fill_partition_guid_array,
+	.get_image_alt_num = fwu_gpt_get_image_alt_num,
+	.metadata_check = fwu_gpt_metadata_check,
+	.revert_boot_index = fwu_gpt_revert_boot_index,
+	.set_accept_image = fwu_gpt_accept_image,
+	.clear_accept_image = fwu_gpt_clear_accept_image,
+	.get_metadata = fwu_gpt_get_metadata,
+};
-- 
2.17.1



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