[RFC PATCH 4/4] block: add uImage.FIT block partition driver

Daniel Golle
2022-11-17T00:46:58Z

Add a small block driver which allows exposing filesystem sub-images
contained in U-Boot uImage.FIT images as block partitions.
The driver is intended for system using the U-Boot bootloader and
requires the user to specify the lower block device to be specified
as module parameter 'lower_dev'.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
MAINTAINERS | 6 +
drivers/block/Kconfig | 6 +
drivers/block/Makefile | 2 +
drivers/block/fitblk.c | 364 +++++++++++++++++++++++++++++++++++++++++
4 files changed, 378 insertions(+)
create mode 100644 drivers/block/fitblk.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 08b67532e374..39402d6d0b9c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -21184,6 +21184,12 @@ F: Documentation/filesystems/ubifs-authentication.rst
F: Documentation/filesystems/ubifs.rst
F: fs/ubifs/

+U-BOOT UIMAGE.FIT PARSER
+M: Daniel Golle <daniel@makrotopia.org>
+L: linux-block@vger.kernel.org
+S: Maintained
+F: drivers/block/fitblk.c
+
UBLK USERSPACE BLOCK DRIVER
M: Ming Lei <ming.lei@redhat.com>
L: linux-block@vger.kernel.org
diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index a41145d52de9..c96c5b9964c7 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -383,6 +383,12 @@ config VIRTIO_BLK
This is the virtual block driver for virtio. It can be used with
QEMU based VMMs (like KVM or Xen). Say Y or M.

+config UIMAGE_FIT_BLK
+ tristate "uImage.FIT block driver"
+ help
+ This is driver allows using filesystems contained in uImage.FIT images
+ by mapping them as block partitions.
+
config BLK_DEV_RBD
tristate "Rados block device (RBD)"
depends on INET && BLOCK
diff --git a/drivers/block/Makefile b/drivers/block/Makefile
index 101612cba303..60ab4fc1442d 100644
--- a/drivers/block/Makefile
+++ b/drivers/block/Makefile
@@ -39,4 +39,6 @@ obj-$(CONFIG_BLK_DEV_NULL_BLK) += null_blk/

obj-$(CONFIG_BLK_DEV_UBLK) += ublk_drv.o

+obj-$(CONFIG_UIMAGE_FIT_BLK) += fitblk.o
+
swim_mod-y := swim.o swim_asm.o
diff --git a/drivers/block/fitblk.c b/drivers/block/fitblk.c
new file mode 100644
index 000000000000..7f959de8c5b2
--- /dev/null
+++ b/drivers/block/fitblk.c
@@ -0,0 +1,364 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * uImage.FIT virtual block device driver.
+ *
+ * Copyright (C) 2022 Daniel Golle
+ * Copyright (C) 2007 Nick Piggin
+ * Copyright (C) 2007 Novell Inc.
+ *
+ * Derived from drivers/block/brd.c which is in parts derived from
+ * drivers/block/rd.c, and drivers/block/loop.c, copyright of their respective
+ * owners.
+ *
+ * uImage.FIT headers extracted from U-Boot mkimage sources
+ * (C) Copyright 2008 Semihalf
+ * (C) Copyright 2000-2005
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ */
+
+#include <linux/init.h>
+#include <linux/initrd.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/major.h>
+#include <linux/blkdev.h>
+#include <linux/blk-mq.h>
+#include <linux/ctype.h>
+#include <linux/hdreg.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_fdt.h>
+#include <linux/pagemap.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/libfdt.h>
+
+#define FIT_IMAGES_PATH "/images"
+#define FIT_CONFS_PATH "/configurations"
+
+/* hash/signature/key node */
+#define FIT_HASH_NODENAME "hash"
+#define FIT_ALGO_PROP "algo"
+#define FIT_VALUE_PROP "value"
+#define FIT_IGNORE_PROP "uboot-ignore"
+#define FIT_SIG_NODENAME "signature"
+#define FIT_KEY_REQUIRED "required"
+#define FIT_KEY_HINT "key-name-hint"
+
+/* cipher node */
+#define FIT_CIPHER_NODENAME "cipher"
+#define FIT_ALGO_PROP "algo"
+
+/* image node */
+#define FIT_DATA_PROP "data"
+#define FIT_DATA_POSITION_PROP "data-position"
+#define FIT_DATA_OFFSET_PROP "data-offset"
+#define FIT_DATA_SIZE_PROP "data-size"
+#define FIT_TIMESTAMP_PROP "timestamp"
+#define FIT_DESC_PROP "description"
+#define FIT_ARCH_PROP "arch"
+#define FIT_TYPE_PROP "type"
+#define FIT_OS_PROP "os"
+#define FIT_COMP_PROP "compression"
+#define FIT_ENTRY_PROP "entry"
+#define FIT_LOAD_PROP "load"
+
+/* configuration node */
+#define FIT_KERNEL_PROP "kernel"
+#define FIT_FILESYSTEM_PROP "filesystem"
+#define FIT_RAMDISK_PROP "ramdisk"
+#define FIT_FDT_PROP "fdt"
+#define FIT_LOADABLE_PROP "loadables"
+#define FIT_DEFAULT_PROP "default"
+#define FIT_SETUP_PROP "setup"
+#define FIT_FPGA_PROP "fpga"
+#define FIT_FIRMWARE_PROP "firmware"
+#define FIT_STANDALONE_PROP "standalone"
+
+#define MIN_FREE_SECT 16
+#define REMAIN_VOLNAME "rootfs_data"
+#define MAX_FIT_LOADABLES 16
+
+static char *lower_dev = NULL;
+static const char *ubootver = NULL;
+static LIST_HEAD(fitblk_devices);
+static DEFINE_MUTEX(devices_mutex);
+
+module_param(lower_dev, charp, 0444);
+MODULE_PARM_DESC(lower_dev, "block device to parse uImage.FIT");
+
+static int parse_fit_on_dev(struct device *dev)
+{
+ struct block_device *bdev = dev_to_bdev(dev);
+ struct gendisk *disk = dev_to_disk(dev);
+ struct address_space *mapping = disk->part0->bd_inode->i_mapping;
+ struct folio *folio;
+ void *fit;
+ u64 dsize, dsectors, imgmaxsect = 0;
+ u32 size, image_pos, image_len;
+ const __be32 *image_offset_be, *image_len_be, *image_pos_be;
+ int ret = 0, node, images, config;
+ const char *image_name, *image_type, *image_description,
+ *config_default, *config_description, *config_loadables;
+ u32 image_name_len, image_type_len, image_description_len,
+ bootconf_len, config_default_len, config_description_len,
+ config_loadables_len;
+ sector_t fit_start_sect = bdev->bd_start_sect, start_sect, nr_sects;
+ struct device_node *np = NULL;
+ const char *bootconf;
+ const char *loadable;
+ bool found;
+ int loadables_rem_len, loadable_len;
+ u16 loadcnt;
+ bool lower_is_part = !(bdev == disk->part0);
+ unsigned int slot = lower_is_part?65:1;
+
+ /* uImage.FIT should be aligned to page boundaries on disk */
+ if (fit_start_sect % (1 << (PAGE_SHIFT - SECTOR_SHIFT)))
+ return -ESPIPE;
+
+ /* map first page */
+ folio = read_mapping_folio(mapping,
+ fit_start_sect >> (PAGE_SHIFT - SECTOR_SHIFT),
+ NULL);
+
+ if (IS_ERR(folio))
+ return PTR_ERR(folio);
+
+ fit = folio_address(folio) +
+ offset_in_folio(folio, fit_start_sect * SECTOR_SIZE);
+
+ /* uImage.FIT is based on flattened device tree structure */
+ if (fdt_check_header(fit)) {
+ ret = -EINVAL;
+ goto ret_out;
+ }
+
+ /* acquire disk size */
+ dsectors = get_capacity(bdev->bd_disk);
+ dsize = dsectors << SECTOR_SHIFT;
+
+ /* silently skip non-external-data legacy uImage.FIT */
+ size = fdt_totalsize(fit);
+ if (size > PAGE_SIZE) {
+ ret = -ENOTSUPP;
+ goto ret_out;
+ }
+
+ /* abort if FIT structure is larger than disk or partition size */
+ if (size >= dsize) {
+ ret = -EFBIG;
+ goto ret_out;
+ }
+
+ /* set boot config node name U-Boot may have added to the device tree */
+ np = of_find_node_by_path("/chosen");
+ if (np)
+ bootconf = of_get_property(np, "u-boot,bootconf", &bootconf_len);
+ else
+ bootconf = NULL;
+
+ /* find configuration path in uImage.FIT */
+ config = fdt_path_offset(fit, FIT_CONFS_PATH);
+ if (config < 0) {
+ pr_err("FIT: Cannot find %s node: %d\n",
+ FIT_CONFS_PATH, config);
+ ret = -ENOENT;
+ goto ret_out;
+ }
+
+ /* get default configuration node name */
+ config_default =
+ fdt_getprop(fit, config, FIT_DEFAULT_PROP, &config_default_len);
+
+ /* make sure we got either default or selected boot config node name */
+ if (!config_default && !bootconf) {
+ pr_err("FIT: Cannot find default configuration\n");
+ ret = -ENOENT;
+ goto ret_out;
+ }
+
+ /* find selected boot config node, fallback on default config node */
+ node = fdt_subnode_offset(fit, config, bootconf ?: config_default);
+ if (node < 0) {
+ pr_err("FIT: Cannot find %s node: %d\n",
+ bootconf ?: config_default, node);
+ ret = -ENOENT;
+ goto ret_out;
+ }
+
+ pr_info("FIT: Detected U-Boot %s\n", ubootver);
+
+ /* get selected configuration data */
+ config_description =
+ fdt_getprop(fit, node, FIT_DESC_PROP, &config_description_len);
+ config_loadables = fdt_getprop(fit, node, FIT_LOADABLE_PROP,
+ &config_loadables_len);
+
+ pr_info("FIT: %s configuration: \"%.*s\"%s%.*s%s\n",
+ bootconf ? "Selected" : "Default",
+ bootconf ? bootconf_len : config_default_len,
+ bootconf ?: config_default,
+ config_description ? " (" : "",
+ config_description ? config_description_len : 0,
+ config_description ?: "",
+ config_description ? ")" : "");
+
+ if (!config_loadables || !config_loadables_len) {
+ pr_err("FIT: No loadables configured in \"%s\"\n",
+ bootconf ?: config_default);
+ ret = -ENOENT;
+ goto ret_out;
+ }
+
+ /* get images path in uImage.FIT */
+ images = fdt_path_offset(fit, FIT_IMAGES_PATH);
+ if (images < 0) {
+ pr_err("FIT: Cannot find %s node: %d\n", FIT_IMAGES_PATH, images);
+ ret = -EINVAL;
+ goto ret_out;
+ }
+
+ /* iterate over images in uImage.FIT */
+ fdt_for_each_subnode(node, fit, images) {
+ image_name = fdt_get_name(fit, node, &image_name_len);
+ image_type = fdt_getprop(fit, node, FIT_TYPE_PROP, &image_type_len);
+ image_offset_be = fdt_getprop(fit, node, FIT_DATA_OFFSET_PROP, NULL);
+ image_pos_be = fdt_getprop(fit, node, FIT_DATA_POSITION_PROP, NULL);
+ image_len_be = fdt_getprop(fit, node, FIT_DATA_SIZE_PROP, NULL);
+
+ if (!image_name || !image_type || !image_len_be)
+ continue;
+
+ image_len = be32_to_cpu(*image_len_be);
+ if (!image_len)
+ continue;
+
+ if (image_offset_be)
+ image_pos = be32_to_cpu(*image_offset_be) + size;
+ else if (image_pos_be)
+ image_pos = be32_to_cpu(*image_pos_be);
+ else
+ continue;
+
+ image_description = fdt_getprop(fit, node, FIT_DESC_PROP,
+ &image_description_len);
+
+ pr_info("FIT: %16s sub-image 0x%08x..0x%08x \"%.*s\"%s%.*s%s\n",
+ image_type, image_pos, image_pos + image_len - 1,
+ image_name_len, image_name, image_description ? " (" : "",
+ image_description ? image_description_len : 0,
+ image_description ?: "", image_description ? ") " : "");
+
+ /* only 'filesystem' images should be mapped as partitions */
+ if (strncmp(image_type, FIT_FILESYSTEM_PROP, image_type_len))
+ continue;
+
+ /* check if sub-image is part of configured loadables */
+ found = false;
+ loadable = config_loadables;
+ loadables_rem_len = config_loadables_len;
+ for (loadcnt = 0; loadables_rem_len > 1 &&
+ loadcnt < MAX_FIT_LOADABLES; ++loadcnt) {
+ loadable_len =
+ strnlen(loadable, loadables_rem_len - 1) + 1;
+ loadables_rem_len -= loadable_len;
+ if (!strncmp(image_name, loadable, loadable_len)) {
+ found = true;
+ break;
+ }
+ loadable += loadable_len;
+ }
+ if (!found)
+ continue;
+
+ if (image_pos % (1 << PAGE_SHIFT)) {
+ pr_err("FIT: image %.*s start not aligned to page boundaries, skipping\n",
+ image_name_len, image_name);
+ continue;
+ }
+
+ if (image_len % (1 << PAGE_SHIFT)) {
+ pr_err("FIT: sub-image %.*s end not aligned to page boundaries, skipping\n",
+ image_name_len, image_name);
+ continue;
+ }
+
+ start_sect = image_pos >> SECTOR_SHIFT;
+ nr_sects = image_len >> SECTOR_SHIFT;
+ imgmaxsect = max_t(sector_t, imgmaxsect, start_sect + nr_sects);
+
+ if (start_sect + nr_sects > dsectors) {
+ pr_err("FIT: sub-image %.*s disk access beyond EOD\n",
+ image_name_len, image_name);
+ continue;
+ }
+
+ bdev_add_partition_ro(disk, slot++, fit_start_sect + start_sect,
+ nr_sects, image_name);
+ }
+
+ /* in case uImage.FIT is stored in a partition, map the remaining space */
+ if (lower_is_part && (imgmaxsect + MIN_FREE_SECT) < dsectors)
+ bdev_add_partition_ro(disk, slot++, fit_start_sect + imgmaxsect,
+ dsectors - imgmaxsect, REMAIN_VOLNAME);
+
+ret_out:
+ folio_put(folio);
+ return ret;
+}
+
+static int fitblk_probe(struct platform_device *pdev)
+{
+ dev_t devt = devt_from_devname(lower_dev);
+ struct device *dev;
+ if (!devt)
+ return -EPROBE_DEFER;
+
+ dev = class_find_device_by_devt(&block_class, devt);
+ if (!dev)
+ return -EPROBE_DEFER;
+
+ return parse_fit_on_dev(dev);
+}
+
+static struct platform_driver fitblk_driver = {
+ .probe = fitblk_probe,
+ .driver = {
+ .name = "fitblk",
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init fitblk_init(void)
+{
+ struct device_node *np;
+
+ if (!lower_dev)
+ return 0;
+
+ /* detect U-Boot firmware */
+ np = of_find_node_by_path("/chosen");
+ if (np)
+ ubootver = of_get_property(np, "u-boot,version", NULL);
+
+ if (!ubootver)
+ return 0;
+
+ platform_device_register_simple("fitblk", -1, NULL, 0);
+ return platform_driver_register(&fitblk_driver);
+}
+module_init(fitblk_init);
+
+static void __exit fitblk_exit(void)
+{
+ platform_driver_unregister(&fitblk_driver);
+}
+module_exit(fitblk_exit);
+
+MODULE_AUTHOR("Daniel Golle");
+MODULE_DESCRIPTION("uImage.FIT virtual block driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:fitblk");
--
2.38.1