[PATCH v1] include: android_bootloader_message.h: sync with AOSP upstream
Igor Opaniuk
igor.opaniuk at foundries.io
Tue Feb 20 20:08:46 CET 2024
Hi Sam,
On Tue, Feb 20, 2024 at 7:29 PM Sam Protsenko
<semen.protsenko at linaro.org> wrote:
>
> On Mon, Feb 19, 2024 at 4:16 AM Igor Opaniuk <igor.opaniuk at gmail.com> wrote:
> >
> > This takes the latest changes from AOSP from [1][2] (as this
> > header was split on two) with minimal changes (this could lead
> > to warnings reported by checkpatch).
>
> Do we want to maybe follow that and also carry two different headers
> in U-Boot? Or it doesn't make much sense? I'm thinking in terms of
> future portability mostly: how easy it's to update this header right
> now, and how easy it's going to be further. I didn't form any opinion
> on that, hence asking.
The problem is licensing. android_bootloader_message.h was
re-licensed by Alex Deymo from Google under BSD-3-Clause,
which is GPLv2 compatible. I'm not sure it's legally correct to pull
boot_control_definition.h from AOSP licensed under Apache as a
separate file.
>
> Another thing: are you sure that changing only the header won't break
> anything in U-Boot .c files that use this header?
I've tested both ab_select and avb verify in QEMU. Or do you mean
something else additionally should be tested?
>
> >
> > Some local changes have been applied:
>
> Is it possible to split this work into two patches:
> 1. Bring the original changes only
> 2. Apply all necessary changes for U-Boot
>
> Or does it break the build, etc? Again, thinking in terms of
> portability easiness, and not sure which approach is better -- just
> asking basically.
Yeah, that's the problem, as splitting this on two commits
will lead to the first one reporting warnings/notes.
>
> > 1. Enable static_assert() for defined structures to be sure
> > that all of them have correct sizes.
> > 2. Adjuste types in bootloader_control structure with bitfields
>
> Adjuste -> adjust
Will fix, thanks!
>
> > (uint8_t -> uint16_t). It seems that gcc just doesn't like bitfields
>
> I wonder if all those extra changes can be upstreamed back to AOSP?
> Ideally we'd want to just copy those headers over from AOSP to U-Boot
> with no changes, would make the porting work easier. What are your
> thoughts on that?
Technically we can, I was planning to do that.
>
> > that cross the width of the type. Changing the type doesn't change
> > the layout though.
> > This addresses this gcc note:
> > In file included from boot/android_ab.c:7:
> > include/android_bootloader_message.h:230:1: note: offset of packed bit-field ‘merge_status’ has changed in GCC 4.4
> > 230 | } __attribute__((packed));
> >
> > [1] https://android.googlesource.com/platform/bootable/recovery/+/main/bootloader_message/include/bootloader_message/bootloader_message.h
> > [2] https://android.googlesource.com/platform/hardware/interfaces/+/main/boot/1.1/default/boot_control/include/private/boot_control_definition.h
> >
> > CC: Alex Deymo <deymo at google.com>
> > CC: Sam Protsenko <semen.protsenko at linaro.org>
> > CC: Eugeniu Rosca <erosca at de.adit-jv.com>
> > CC: Simon Glass <sjg at chromium.org>
> > Signed-off-by: Igor Opaniuk <igor.opaniuk at gmail.com>
> > ---
> >
> > include/android_bootloader_message.h | 104 +++++++++++++++++++++++----
> > 1 file changed, 92 insertions(+), 12 deletions(-)
> >
> > diff --git a/include/android_bootloader_message.h b/include/android_bootloader_message.h
> > index 286d7ab0f31..75198fc9dc2 100644
> > --- a/include/android_bootloader_message.h
> > +++ b/include/android_bootloader_message.h
> > @@ -21,17 +21,22 @@
> > * stddef.h
> > */
> > #include <compiler.h>
> > +#include <linux/build_bug.h>
> > #endif
> >
> > // Spaces used by misc partition are as below:
> > // 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
> > +// 16K - 32K Used by uncrypt and recovery to store wipe_package for A/B devices
> > +// 32K - 64K System space, used for miscellanious AOSP features. See below.
> > // 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 VENDOR_SPACE_OFFSET_IN_MISC = 2 * 1024;
> > static const size_t WIPE_PACKAGE_OFFSET_IN_MISC = 16 * 1024;
> > +static const size_t SYSTEM_SPACE_OFFSET_IN_MISC = 32 * 1024;
> > +static const size_t SYSTEM_SPACE_SIZE_IN_MISC = 32 * 1024;
> >
> > /* Bootloader Message (2-KiB)
> > *
> > @@ -81,24 +86,67 @@ struct bootloader_message {
> > char reserved[1184];
> > };
> >
> > +// Holds Virtual A/B merge status information. Current version is 1. New fields
> > +// must be added to the end.
> > +struct misc_virtual_ab_message {
> > + uint8_t version;
> > + uint32_t magic;
> > + uint8_t merge_status; // IBootControl 1.1, MergeStatus enum.
> > + uint8_t source_slot; // Slot number when merge_status was written.
> > + uint8_t reserved[57];
> > +} __attribute__((packed));
> > +
> > +struct misc_memtag_message {
> > + uint8_t version;
> > + uint32_t magic; // magic string for treble compat
> > + uint32_t memtag_mode;
> > + uint8_t reserved[55];
> > +} __attribute__((packed));
> > +
> > +struct misc_kcmdline_message {
> > + uint8_t version;
> > + uint32_t magic;
> > + uint64_t kcmdline_flags;
> > + uint8_t reserved[51];
> > +} __attribute__((packed));
> > +
> > +#define MISC_VIRTUAL_AB_MESSAGE_VERSION 2
> > +#define MISC_VIRTUAL_AB_MAGIC_HEADER 0x56740AB0
> > +
> > +#define MISC_MEMTAG_MESSAGE_VERSION 1
> > +#define MISC_MEMTAG_MAGIC_HEADER 0x5afefe5a
> > +#define MISC_MEMTAG_MODE_MEMTAG 0x1
> > +#define MISC_MEMTAG_MODE_MEMTAG_ONCE 0x2
> > +#define MISC_MEMTAG_MODE_MEMTAG_KERNEL 0x4
> > +#define MISC_MEMTAG_MODE_MEMTAG_KERNEL_ONCE 0x8
> > +#define MISC_MEMTAG_MODE_MEMTAG_OFF 0x10
> > +// This is set when the state was overridden forcibly. This does not need to be
> > +// interpreted by the bootloader but is only for bookkeeping purposes so
> > +// userspace knows what to do when the override is undone.
> > +// See system/extras/mtectrl in AOSP for more information.
> > +#define MISC_MEMTAG_MODE_FORCED 0x20
> > +
> > +#define MISC_KCMDLINE_MESSAGE_VERSION 1
> > +#define MISC_KCMDLINE_MAGIC_HEADER 0x6ab5110c
> > +#define MISC_KCMDLINE_BINDER_RUST 0x1
> > /**
> > * We must be cautious when changing the bootloader_message struct size,
> > * because A/B-specific fields may end up with different offsets.
> > */
> > -#ifndef __UBOOT__
> > +
> > #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
> > -#endif /* __UBOOT__ */
> >
> > /**
> > * 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.
> > + * stays after struct bootloader_message, which belongs to the vendor
> > + * space of /misc partition. Also, the A/B-specific contents 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
> > @@ -124,12 +172,10 @@ struct bootloader_message_ab {
> > * Be cautious about the struct size change, in case we put anything post
> > * bootloader_message_ab struct (b/29159185).
> > */
> > -#ifndef __UBOOT__
> > #if (__STDC_VERSION__ >= 201112L) || defined(__cplusplus)
> > static_assert(sizeof(struct bootloader_message_ab) == 4096,
> > "struct bootloader_message_ab size changes");
> > #endif
> > -#endif /* __UBOOT__ */
> >
> > #define BOOT_CTRL_MAGIC 0x42414342 /* Bootloader Control AB */
> > #define BOOT_CTRL_VERSION 1
> > @@ -165,11 +211,13 @@ struct bootloader_control {
> > // Version of struct being used (see BOOT_CTRL_VERSION).
> > uint8_t version;
> > // Number of slots being managed.
> > - uint8_t nb_slot : 3;
> > + uint16_t nb_slot : 3;
> > // Number of times left attempting to boot recovery.
> > - uint8_t recovery_tries_remaining : 3;
> > + uint16_t recovery_tries_remaining : 3;
> > + // Status of any pending snapshot merge of dynamic partitions.
> > + uint16_t merge_status : 3;
> > // Ensure 4-bytes alignment for slot_info field.
> > - uint8_t reserved0[2];
> > + uint8_t reserved0[1];
> > // Per-slot information. Up to 4 slots.
> > struct slot_metadata slot_info[4];
> > // Reserved for further use.
> > @@ -179,25 +227,46 @@ struct bootloader_control {
> > uint32_t crc32_le;
> > } __attribute__((packed));
> >
> > -#ifndef __UBOOT__
> > #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");
> > +static_assert(sizeof(struct misc_virtual_ab_message) == 64,
> > + "struct misc_virtual_ab_message has wrong size");
> > +static_assert(sizeof(struct misc_memtag_message) == 64,
> > + "struct misc_memtag_message has wrong size");
> > +static_assert(sizeof(struct misc_kcmdline_message) == 64,
> > + "struct misc_kcmdline_message has wrong size");
> > #endif
> > -#endif /* __UBOOT__ */
> >
> > #ifndef __UBOOT__
> > +
> > +// This struct is not meant to be used directly, rather, it is to make
> > +// computation of offsets easier. New fields must be added to the end.
> > +struct misc_system_space_layout {
> > + misc_virtual_ab_message virtual_ab_message;
> > + misc_memtag_message memtag_message;
> > + misc_kcmdline_message kcmdline_message;
> > +} __attribute__((packed));
> > +
> > #ifdef __cplusplus
> >
> > #include <string>
> > #include <vector>
> >
> > +// Gets the block device name of /misc partition.
> > +std::string get_misc_blk_device(std::string* err);
> > +
> > // Return the block device name for the bootloader message partition and waits
> > // for the device for up to 10 seconds. In case of error returns the empty
> > // string.
> > std::string get_bootloader_message_blk_device(std::string* err);
> >
> > +// Writes |size| bytes of data from buffer |p| to |misc_blk_device| at |offset|. If the write fails,
> > +// sets the error message in |err|.
> > +bool write_misc_partition(const void* p, size_t size, const std::string& misc_blk_device,
> > + size_t offset, std::string* err);
> > +
> > // Read bootloader message into boot. Error message will be set in err.
> > bool read_bootloader_message(bootloader_message* boot, std::string* err);
> >
> > @@ -242,6 +311,17 @@ bool read_wipe_package(std::string* package_data, size_t size, std::string* err)
> > // Write the wipe package into BCB (to offset WIPE_PACKAGE_OFFSET_IN_MISC).
> > bool write_wipe_package(const std::string& package_data, std::string* err);
> >
> > +// Read or write the Virtual A/B message from system space in /misc.
> > +bool ReadMiscVirtualAbMessage(misc_virtual_ab_message* message, std::string* err);
> > +bool WriteMiscVirtualAbMessage(const misc_virtual_ab_message& message, std::string* err);
> > +
> > +// Read or write the memtag message from system space in /misc.
> > +bool ReadMiscMemtagMessage(misc_memtag_message* message, std::string* err);
> > +bool WriteMiscMemtagMessage(const misc_memtag_message& message, std::string* err);
> > +
> > +// Read or write the kcmdline message from system space in /misc.
> > +bool ReadMiscKcmdlineMessage(misc_kcmdline_message* message, std::string* err);
> > +bool WriteMiscKcmdlineMessage(const misc_kcmdline_message& message, std::string* err);
>
> AFAIU, these new prototypes brought by this patch don't have actual
> implementation yet. Does it affect the build somehow, e.g. maybe
> causing some build warnings? Or is the build log clean?
They are all wrapped with #ifndef __UBOOT__.
>
> > #else
> >
> > #include <stdbool.h>
> > --
> > 2.34.1
> >
Thanks for your comments!
--
Best regards - Freundliche Grüsse - Meilleures salutations
Igor Opaniuk
Senior Software Engineer, Embedded & Security
E: igor.opaniuk at foundries.io
W: www.foundries.io
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