[PATCH v2 04/17] android: boot: add boot image header v3 and v4 structures

Safae Ouajih
2023-01-26T16:07:15Z

This adds support for v3/v4 boot image format by adding
the following structures:

- andr_boot_img_hdr_v3 : describes boot image header
- andr_vendor_img_hdr : describes vendor boot image header

These definitions have been copied over from the AOSP documentation at
[1] and [2]

Boot arg sizes are taken from [3]:
commit: 35fb6262bc3f (ANDROID: Support for vendor boot)

This also adds documentation for boot image header v3/v4 structure
that was imported from [4], file: include/bootimg/bootimg.h
commit: 8d0922bfb932 (Adding GKI signature in boot.img v4)

Link:[1] https://source.android.com/docs/core/architecture/bootloader/boot-image-header
Link:[2] https://source.android.com/docs/core/architecture/bootloader/partitions/vendor-boot-partitions#vendor-boot-header
Link:[3] https://android.googlesource.com/platform/external/u-boot
Link:[4] https://android.googlesource.com/platform/system/tools/mkbootimg

Signed-off-by: Safae Ouajih <souajih@baylibre.com>
---
include/android_image.h | 183 +++++++++++++++++++++++++++++++++++++++-
1 file changed, 182 insertions(+), 1 deletion(-)

diff --git a/include/android_image.h b/include/android_image.h
index 2bdcab9122..4fce363ff7 100644
--- a/include/android_image.h
+++ b/include/android_image.h
@@ -3,7 +3,7 @@
* This is from the Android Project,
* Repository: https://android.googlesource.com/platform/system/tools/mkbootimg
* File: include/bootimg/bootimg.h
- * Commit: e55998a0f2b61b685d5eb4a486ca3a0c680b1a2f
+ * Commit: cce5b1923e3cd2fcb765b512610bdc5c42bc501d
*
* Copyright (C) 2007 The Android Open Source Project
*/
@@ -14,11 +14,58 @@
#include <linux/compiler.h>
#include <linux/types.h>

+#define ANDR_GKI_PAGE_SIZE 4096
#define ANDR_BOOT_MAGIC "ANDROID!"
#define ANDR_BOOT_MAGIC_SIZE 8
#define ANDR_BOOT_NAME_SIZE 16
#define ANDR_BOOT_ARGS_SIZE 512
#define ANDR_BOOT_EXTRA_ARGS_SIZE 1024
+#define VENDOR_BOOT_MAGIC "VNDRBOOT"
+#define ANDR_VENDOR_BOOT_MAGIC_SIZE 8
+#define ANDR_VENDOR_BOOT_ARGS_SIZE 2048
+#define ANDR_VENDOR_BOOT_NAME_SIZE 16
+
+struct andr_boot_img_hdr_v3 {
+ u8 magic[ANDR_BOOT_MAGIC_SIZE];
+
+ u32 kernel_size; /* size in bytes */
+ u32 ramdisk_size; /* size in bytes */
+
+ u32 os_version;
+
+ u32 header_size; /* size of boot image header in bytes */
+ u32 reserved[4];
+ u32 header_version; /* offset remains constant for version check */
+
+ u8 cmdline[ANDR_BOOT_ARGS_SIZE + ANDR_BOOT_EXTRA_ARGS_SIZE];
+ /* for boot image header v4 only */
+ u32 signature_size; /* size in bytes */
+};
+
+struct andr_vendor_img_hdr {
+ u8 magic[ANDR_VENDOR_BOOT_MAGIC_SIZE];
+ u32 header_version;
+ u32 page_size; /* flash page size we assume */
+
+ u32 kernel_addr; /* physical load addr */
+ u32 ramdisk_addr; /* physical load addr */
+
+ u32 vendor_ramdisk_size; /* size in bytes */
+
+ u8 cmdline[ANDR_VENDOR_BOOT_ARGS_SIZE];
+
+ u32 tags_addr; /* physical addr for kernel tags */
+
+ u8 name[ANDR_VENDOR_BOOT_NAME_SIZE]; /* asciiz product name */
+ u32 header_size; /* size of vendor boot image header in bytes */
+ u32 dtb_size; /* size of dtb image */
+ u64 dtb_addr; /* physical load address */
+ /* for boot image header v4 only */
+ u32 vendor_ramdisk_table_size; /* size in bytes for the vendor ramdisk table */
+ u32 vendor_ramdisk_table_entry_num; /* number of entries in the vendor ramdisk table */
+ u32 vendor_ramdisk_table_entry_size; /* size in bytes for a vendor ramdisk table entry */
+ u32 bootconfig_size; /* size in bytes for the bootconfig section */
+};

/* The bootloader expects the structure of andr_boot_img_hdr_v0 with header
* version 0 to be as follows: */
@@ -136,4 +183,138 @@ struct andr_boot_img_hdr_v0 {
* else: jump to kernel_addr
*/

+/* When the boot image header has a version of 3, the structure of the boot
+ * image is as follows:
+ *
+ * +---------------------+
+ * | boot header | 4096 bytes
+ * +---------------------+
+ * | kernel | m pages
+ * +---------------------+
+ * | ramdisk | n pages
+ * +---------------------+
+ *
+ * m = (kernel_size + 4096 - 1) / 4096
+ * n = (ramdisk_size + 4096 - 1) / 4096
+ *
+ * Note that in version 3 of the boot image header, page size is fixed at 4096 bytes.
+ *
+ * The structure of the vendor boot image (introduced with version 3 and
+ * required to be present when a v3 boot image is used) is as follows:
+ *
+ * +---------------------+
+ * | vendor boot header | o pages
+ * +---------------------+
+ * | vendor ramdisk | p pages
+ * +---------------------+
+ * | dtb | q pages
+ * +---------------------+
+ * o = (2112 + page_size - 1) / page_size
+ * p = (vendor_ramdisk_size + page_size - 1) / page_size
+ * q = (dtb_size + page_size - 1) / page_size
+ *
+ * 0. all entities in the boot image are 4096-byte aligned in flash, all
+ * entities in the vendor boot image are page_size (determined by the vendor
+ * and specified in the vendor boot image header) aligned in flash
+ * 1. kernel, ramdisk, vendor ramdisk, and DTB are required (size != 0)
+ * 2. load the kernel and DTB at the specified physical address (kernel_addr,
+ * dtb_addr)
+ * 3. load the vendor ramdisk at ramdisk_addr
+ * 4. load the generic ramdisk immediately following the vendor ramdisk in
+ * memory
+ * 5. set up registers for kernel entry as required by your architecture
+ * 6. if the platform has a second stage bootloader jump to it (must be
+ * contained outside boot and vendor boot partitions), otherwise
+ * jump to kernel_addr
+ */
+
+/* When the boot image header has a version of 4, the structure of the boot
+ * image is as follows:
+ *
+ * +---------------------+
+ * | boot header | 4096 bytes
+ * +---------------------+
+ * | kernel | m pages
+ * +---------------------+
+ * | ramdisk | n pages
+ * +---------------------+
+ * | boot signature | g pages
+ * +---------------------+
+ *
+ * m = (kernel_size + 4096 - 1) / 4096
+ * n = (ramdisk_size + 4096 - 1) / 4096
+ * g = (signature_size + 4096 - 1) / 4096
+ *
+ * Note that in version 4 of the boot image header, page size is fixed at 4096
+ * bytes.
+ *
+ * The structure of the vendor boot image version 4, which is required to be
+ * present when a version 4 boot image is used, is as follows:
+ *
+ * +------------------------+
+ * | vendor boot header | o pages
+ * +------------------------+
+ * | vendor ramdisk section | p pages
+ * +------------------------+
+ * | dtb | q pages
+ * +------------------------+
+ * | vendor ramdisk table | r pages
+ * +------------------------+
+ * | bootconfig | s pages
+ * +------------------------+
+ *
+ * o = (2128 + page_size - 1) / page_size
+ * p = (vendor_ramdisk_size + page_size - 1) / page_size
+ * q = (dtb_size + page_size - 1) / page_size
+ * r = (vendor_ramdisk_table_size + page_size - 1) / page_size
+ * s = (vendor_bootconfig_size + page_size - 1) / page_size
+ *
+ * Note that in version 4 of the vendor boot image, multiple vendor ramdisks can
+ * be included in the vendor boot image. The bootloader can select a subset of
+ * ramdisks to load at runtime. To help the bootloader select the ramdisks, each
+ * ramdisk is tagged with a type tag and a set of hardware identifiers
+ * describing the board, soc or platform that this ramdisk is intended for.
+ *
+ * The vendor ramdisk section is consist of multiple ramdisk images concatenated
+ * one after another, and vendor_ramdisk_size is the size of the section, which
+ * is the total size of all the ramdisks included in the vendor boot image.
+ *
+ * The vendor ramdisk table holds the size, offset, type, name and hardware
+ * identifiers of each ramdisk. The type field denotes the type of its content.
+ * The vendor ramdisk names are unique. The hardware identifiers are specified
+ * in the board_id field in each table entry. The board_id field is consist of a
+ * vector of unsigned integer words, and the encoding scheme is defined by the
+ * hardware vendor.
+ *
+ * For the different type of ramdisks, there are:
+ * - VENDOR_RAMDISK_TYPE_NONE indicates the value is unspecified.
+ * - VENDOR_RAMDISK_TYPE_PLATFORM ramdisks contain platform specific bits, so
+ * the bootloader should always load these into memory.
+ * - VENDOR_RAMDISK_TYPE_RECOVERY ramdisks contain recovery resources, so
+ * the bootloader should load these when booting into recovery.
+ * - VENDOR_RAMDISK_TYPE_DLKM ramdisks contain dynamic loadable kernel
+ * modules.
+ *
+ * Version 4 of the vendor boot image also adds a bootconfig section to the end
+ * of the image. This section contains Boot Configuration parameters known at
+ * build time. The bootloader is responsible for placing this section directly
+ * after the generic ramdisk, followed by the bootconfig trailer, before
+ * entering the kernel.
+ *
+ * 0. all entities in the boot image are 4096-byte aligned in flash, all
+ * entities in the vendor boot image are page_size (determined by the vendor
+ * and specified in the vendor boot image header) aligned in flash
+ * 1. kernel, ramdisk, and DTB are required (size != 0)
+ * 2. load the kernel and DTB at the specified physical address (kernel_addr,
+ * dtb_addr)
+ * 3. load the vendor ramdisks at ramdisk_addr
+ * 4. load the generic ramdisk immediately following the vendor ramdisk in
+ * memory
+ * 5. load the bootconfig immediately following the generic ramdisk. Add
+ * additional bootconfig parameters followed by the bootconfig trailer.
+ * 6. set up registers for kernel entry as required by your architecture
+ * 7. if the platform has a second stage bootloader jump to it (must be
+ * contained outside boot and vendor boot partitions), otherwise
+ * jump to kernel_addr
+ */
#endif
--
2.34.1