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-rw-r--r--bootloader.h120
1 files changed, 110 insertions, 10 deletions
diff --git a/bootloader.h b/bootloader.h
index 88d54a5cb..341bcadbd 100644
--- a/bootloader.h
+++ b/bootloader.h
@@ -17,18 +17,20 @@
#ifndef _RECOVERY_BOOTLOADER_H
#define _RECOVERY_BOOTLOADER_H
+#include <assert.h>
#include <stddef.h>
// Spaces used by misc partition are as below:
-// 0 - 2K Bootloader Message
-// 2K - 16K Used by Vendor's bootloader
+// 0 - 2K For bootloader_message
+// 2K - 16K Used by Vendor's bootloader (the 2K - 4K range may be optionally used
+// as bootloader_message_ab struct)
// 16K - 64K Used by uncrypt and recovery to store wipe_package for A/B devices
// Note that these offsets are admitted by bootloader,recovery and uncrypt, so they
// are not configurable without changing all of them.
static const size_t BOOTLOADER_MESSAGE_OFFSET_IN_MISC = 0;
static const size_t WIPE_PACKAGE_OFFSET_IN_MISC = 16 * 1024;
-/* Bootloader Message
+/* Bootloader Message (2-KiB)
*
* This structure describes the content of a block in flash
* that is used for recovery and the bootloader to talk to
@@ -51,12 +53,10 @@ static const size_t WIPE_PACKAGE_OFFSET_IN_MISC = 16 * 1024;
* package it is. If the value is of the format "#/#" (eg, "1/3"),
* the UI will add a simple indicator of that status.
*
- * The slot_suffix field is used for A/B implementations where the
- * bootloader does not set the androidboot.ro.boot.slot_suffix kernel
- * commandline parameter. This is used by fs_mgr to mount /system and
- * other partitions with the slotselect flag set in fstab. A/B
- * implementations are free to use all 32 bytes and may store private
- * data past the first NUL-byte in this field.
+ * We used to have slot_suffix field for A/B boot control metadata in
+ * this struct, which gets unintentionally cleared by recovery or
+ * uncrypt. Move it into struct bootloader_message_ab to avoid the
+ * issue.
*/
struct bootloader_message {
char command[32];
@@ -69,10 +69,110 @@ struct bootloader_message {
// stage string (for multistage packages) and possible future
// expansion.
char stage[32];
+
+ // The 'reserved' field used to be 224 bytes when it was initially
+ // carved off from the 1024-byte recovery field. Bump it up to
+ // 1184-byte so that the entire bootloader_message struct rounds up
+ // to 2048-byte.
+ char reserved[1184];
+};
+
+/**
+ * We must be cautious when changing the bootloader_message struct size,
+ * because A/B-specific fields may end up with different offsets.
+ */
+#if (__STDC_VERSION__ >= 201112L) || defined(__cplusplus)
+static_assert(sizeof(struct bootloader_message) == 2048,
+ "struct bootloader_message size changes, which may break A/B devices");
+#endif
+
+/**
+ * The A/B-specific bootloader message structure (4-KiB).
+ *
+ * We separate A/B boot control metadata from the regular bootloader
+ * message struct and keep it here. Everything that's A/B-specific
+ * stays after struct bootloader_message, which should be managed by
+ * the A/B-bootloader or boot control HAL.
+ *
+ * The slot_suffix field is used for A/B implementations where the
+ * bootloader does not set the androidboot.ro.boot.slot_suffix kernel
+ * commandline parameter. This is used by fs_mgr to mount /system and
+ * other partitions with the slotselect flag set in fstab. A/B
+ * implementations are free to use all 32 bytes and may store private
+ * data past the first NUL-byte in this field. It is encouraged, but
+ * not mandatory, to use 'struct bootloader_control' described below.
+ */
+struct bootloader_message_ab {
+ struct bootloader_message message;
char slot_suffix[32];
- char reserved[192];
+
+ // Round up the entire struct to 4096-byte.
+ char reserved[2016];
};
+/**
+ * Be cautious about the struct size change, in case we put anything post
+ * bootloader_message_ab struct (b/29159185).
+ */
+#if (__STDC_VERSION__ >= 201112L) || defined(__cplusplus)
+static_assert(sizeof(struct bootloader_message_ab) == 4096,
+ "struct bootloader_message_ab size changes");
+#endif
+
+#define BOOT_CTRL_MAGIC 0x42414342 /* Bootloader Control AB */
+#define BOOT_CTRL_VERSION 1
+
+struct slot_metadata {
+ // Slot priority with 15 meaning highest priority, 1 lowest
+ // priority and 0 the slot is unbootable.
+ uint8_t priority : 4;
+ // Number of times left attempting to boot this slot.
+ uint8_t tries_remaining : 3;
+ // 1 if this slot has booted successfully, 0 otherwise.
+ uint8_t successful_boot : 1;
+ // 1 if this slot is corrupted from a dm-verity corruption, 0
+ // otherwise.
+ uint8_t verity_corrupted : 1;
+ // Reserved for further use.
+ uint8_t reserved : 7;
+} __attribute__((packed));
+
+/* Bootloader Control AB
+ *
+ * This struct can be used to manage A/B metadata. It is designed to
+ * be put in the 'slot_suffix' field of the 'bootloader_message'
+ * structure described above. It is encouraged to use the
+ * 'bootloader_control' structure to store the A/B metadata, but not
+ * mandatory.
+ */
+struct bootloader_control {
+ // NUL terminated active slot suffix.
+ char slot_suffix[4];
+ // Bootloader Control AB magic number (see BOOT_CTRL_MAGIC).
+ uint32_t magic;
+ // Version of struct being used (see BOOT_CTRL_VERSION).
+ uint8_t version;
+ // Number of slots being managed.
+ uint8_t nb_slot : 3;
+ // Number of times left attempting to boot recovery.
+ uint8_t recovery_tries_remaining : 3;
+ // Ensure 4-bytes alignment for slot_info field.
+ uint8_t reserved0[2];
+ // Per-slot information. Up to 4 slots.
+ struct slot_metadata slot_info[4];
+ // Reserved for further use.
+ uint8_t reserved1[8];
+ // CRC32 of all 28 bytes preceding this field (little endian
+ // format).
+ uint32_t crc32_le;
+} __attribute__((packed));
+
+#if (__STDC_VERSION__ >= 201112L) || defined(__cplusplus)
+static_assert(sizeof(struct bootloader_control) ==
+ sizeof(((struct bootloader_message_ab *)0)->slot_suffix),
+ "struct bootloader_control has wrong size");
+#endif
+
/* Read and write the bootloader command from the "misc" partition.
* These return zero on success.
*/