From 9fb2b592e2dd8884cb5343cc0233ede3b7af8b29 Mon Sep 17 00:00:00 2001 From: Tao Bao Date: Thu, 9 Jun 2016 12:10:54 -0700 Subject: Add bootloader_message_ab struct. Move A/B-specific fields, effectively slot_suffix as in this CL, out of bootloader_message struct. Those A/B-specific fields are expected to be managed by the A/B-bootloader or boot control HAL, which shouldn't be cleared by recovery or uncrypt. Round up the bootloader_message struct to 2-KiB. Round up the bootloader_message_ab struct to 4-KiB. Bug: 29193360 Change-Id: I5740a612456da6d4d3b00e49a202d8f689d32690 --- bootloader.h | 71 +++++++++++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 58 insertions(+), 13 deletions(-) (limited to 'bootloader.h') diff --git a/bootloader.h b/bootloader.h index de5351851..1801705fb 100644 --- a/bootloader.h +++ b/bootloader.h @@ -17,7 +17,9 @@ #ifndef _RECOVERY_BOOTLOADER_H #define _RECOVERY_BOOTLOADER_H -/* Bootloader Message +#include + +/* 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 @@ -40,13 +42,10 @@ * 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. It is encouraged, but - * not mandatory, to use 'struct bootloader_control' described below. + * 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]; @@ -59,10 +58,56 @@ 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 @@ -111,10 +156,10 @@ struct bootloader_control { uint32_t crc32_le; } __attribute__((packed)); -#if (__STDC_VERSION__ >= 201112L) -_Static_assert(sizeof(struct bootloader_control) == - sizeof(((struct bootloader_message *)0)->slot_suffix), - "struct bootloader_control has wrong size"); +#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. -- cgit v1.2.3