[RFC PATCH v3 0/9] FWU: Add support for FWU Multi Bank Update feature

Fri Jan 21 08:15:23 CET 2022

hi Heinrich,

On Thu, 20 Jan 2022 at 15:39, Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
>
> On 1/19/22 19:55, Sughosh Ganu wrote:
> > The patchset adds support for the FWU Multi Bank Update[1]
> > feature. Certain aspects of the Dependable Boot[2] specification have
> > also been implemented.
>
> The document "Platform Security Firmware Update for the A-profile Arm
> Architecture Beta" [1] that you relate to describes updating using FF-A
> [5] as a communication protocol between a normal world client and an
> update agent in the secure world. [1] further describes an API for this
> communication. I cannot see that you are implementing this:
>
> * U-Boot is living in the normal world, so it cannot be the update agent
> of [1].
> * Implementing the client of [1] in U-Boot would not require board
> specific changes.

This document also describes, in brief, the scenario where the
firmware store is controlled by Normal World firmware. Please check
"Normal World Controlled Firmware Store" on pg 39 of this document.
This section mentions that for such a scenario the Client is the
Update Agent.

>
> This patch set comes without any documentation update. We need a patch
> which adds documents to U-Boot describing
>
> * the design of the update mechanism
> * the usage of the update mechanism
>
> before we can start the review of the patches.

Okay. Will add some documentation for this patch series in my next version.

-sughosh

>
> Best regards
>
> Heinrich
>
> [1] Platform Security Firmware Update for the A-profile Arm Architecture
> Beta
> https://developer.arm.com/documentation/den0118/a
>
> [5] Arm Firmware Framework for Arm A-profile
> https://developer.arm.com/documentation/den0077/latest
>
> >
> > The FWU multi bank update feature is used for supporting multiple
> > sets(also called banks) of firmware image(s), allowing the platform to
> > boot from a different bank, in case it fails to boot from the active
> > bank. This functionality is supported by keeping the relevant
> > information in a structure called metadata, which provides information
> > on the images. Among other parameters, the metadata structure contains
> > information on the currect active bank that is being used to boot
> > image(s).
> >
> > Functionality is being added to work with the UEFI capsule driver in
> > u-boot. The metadata is read to gather information on the update bank,
> > which is the bank to which the firmware images would be flashed to. On
> > a successful completion of the update of all components, the active
> > bank field in the metadata is updated, to reflect the bank from which
> > the platform will boot on the subsequent boots.
> >
> > Currently, the feature is being enabled on the STM32MP157C-DK2
> > board which boots a FIP image from a uSD card partitioned with the GPT
> > partioning scheme. This also requires changes in the previous stage of
> > bootloader, which parses the metadata and selects the bank to boot the
> > image(s) from. Support is being added in tf-a(BL2 stage) for the
> > STM32MP157C-DK2 board to boot the active bank images. These changes
> > are under review currently[3].
>   >
> > These patches are based on top of the series from Takahiro to add
> > Authentication support to mkeficapsule utility[4]
> >
> > [1] - https://developer.arm.com/documentation/den0118/a
> > [2] - https://staging-git.codelinaro.org/linaro/firmware-dual-banked-updates/test
> > [3] - https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/12566
> > [4] - https://patchwork.ozlabs.org/project/uboot/list/?series=281549
> >
> > Changes since V2:
> > * Use uint*_t types in fwu_mdata.h since the file is to be reused in
> >    other projects
> > * Keep only the FWU metadata structures in fwu_mdata.h
> > * Move all other function and macro declarations in fwu.h
> > * Keep common implementations of fwu_update_active_index and
> >    fwu_revert_boot_index in fwu_mdata.c
> > * Add a update_mdata function pointer in the fwu_mdata_ops structure
> > * Move the function definition of fwu_verify_mdata to fwu_mdata.c to
> >    facilitate reuse
> > * Remove the block device specific desc->devnum parameter for the
> >    fwu_plat_get_alt_num function call
> > * Change the implementation of fwu_plat_get_alt_num to get the devnum
> >    in the function before calling gpt_plat_get_alt_num
> > * Add logic to delete the TrialStateCtr variable if system is not in
> >    Trial State
> > * Add logic to check if bit 15(OS Acceptance) of the Flags member in
> >    the capsule header is set
> > * Add logic to set the accept bit of all images from a capsule if the
> >    OS Acceptance bit in the capsule header is not set
> > * Include the log.h and stdio.h header files
> >
> > Sughosh Ganu (9):
> >    FWU: Add FWU metadata structure and functions for accessing metadata
> >    FWU: Add FWU metadata access functions for GPT partitioned block
> >      devices
> >    FWU: stm32mp1: Add helper functions for accessing FWU metadata
> >    FWU: STM32MP1: Add support to read boot index from backup register
> >    EFI: FMP: Add provision to update image's ImageTypeId in image
> >      descriptor
> >    FWU: Add boot time checks as highlighted by the FWU specification
> >    FWU: Add support for FWU Multi Bank Update feature
> >    FWU: cmd: Add a command to read FWU metadata
> >    mkeficapsule: Add support for generating empty capsules
> >
> >   board/st/stm32mp1/stm32mp1.c        | 183 ++++++++++
> >   cmd/Kconfig                         |   7 +
> >   cmd/Makefile                        |   1 +
> >   cmd/fwu_mdata.c                     |  67 ++++
> >   common/board_r.c                    |   6 +
> >   include/fwu.h                       |  81 +++++
> >   include/fwu_mdata.h                 |  69 ++++
> >   lib/Kconfig                         |   6 +
> >   lib/Makefile                        |   1 +
> >   lib/efi_loader/efi_capsule.c        | 233 ++++++++++++-
> >   lib/efi_loader/efi_firmware.c       |  90 ++++-
> >   lib/efi_loader/efi_setup.c          |   3 +-
> >   lib/fwu_updates/Kconfig             |  31 ++
> >   lib/fwu_updates/Makefile            |  11 +
> >   lib/fwu_updates/fwu.c               | 198 +++++++++++
> >   lib/fwu_updates/fwu_mdata.c         | 358 +++++++++++++++++++
> >   lib/fwu_updates/fwu_mdata_gpt_blk.c | 521 ++++++++++++++++++++++++++++
> >   tools/eficapsule.h                  |   8 +
> >   tools/mkeficapsule.c                | 102 +++++-
> >   19 files changed, 1955 insertions(+), 21 deletions(-)
> >   create mode 100644 cmd/fwu_mdata.c
> >   create mode 100644 include/fwu.h
> >   create mode 100644 include/fwu_mdata.h
> >   create mode 100644 lib/fwu_updates/Kconfig
> >   create mode 100644 lib/fwu_updates/Makefile
> >   create mode 100644 lib/fwu_updates/fwu.c
> >   create mode 100644 lib/fwu_updates/fwu_mdata.c
> >   create mode 100644 lib/fwu_updates/fwu_mdata_gpt_blk.c
> >
>