Hi Suresh,
I think still there is some misunderstanding here about the role of MCUboot in the update process.
I try to clarify it:
* MCUboot is the *bootloader* in the system, it does not care how the new images are getting installed on the device.
* MCUboot defines a static allocation of the flash. There are the primary slot where the active runtime images are stored and executed from there (if upgrade startegy is XIP) and there are the secondary slot where the candidate image is written by the update client, which his part of the runtime firmware.
* MCUboot is not involved at all in the process when new image is downloaded from the remote server and written to the flash (to secondary slot).
* MCUboot jobs to recognize that there is a new image (magic value is set at the end of secondary slot), validates it (hash + signature) and move it (if valid) to the primary slot to make it executable (because image is XIP and linked to the address space of the primary slot)
* When moving is done just jumps to the reset handler of the new image.
TF-M expose a standard FWU API, which can be used by any cloud client:
* FWU partition in the secure side is responsible to write the new image to the flash
* Because TF-M relies on MCUBoot as a bootloader therefore the image must be placed to the right place in the flash (secondary slot) and some MCUboot specific flags must be set (magic value to indicate new image existence). Therefore in the FWU secure partition there is a MCUboot shim layer to handle these bootloader specific task
* However, MCUBoot can replaced by any bootloader if one wants and then the shim layer also can be replaced to do other bootloader specific things.
* In this architecture update client is responsible to download the image from the remote server and the FWU partition is responsible to write it to the right location.
An implementer can choose:
* Implement the FWU API on the non-secure side
* Do not use FWU API, just writes the image to the right flash location and set certain flags in the flash that allows MCUboot to find the image
* Replace MCUboot with custom bootloader if he wants
I hope this helps!
The call path in the previous mail was incorrect. The correct call path is:
Update client application
|
| Function call
V
FWU API
|
| TF-M psa_call() etc.
V
FWU Partition
|
| Function call
V
MCUBoot Shim Layer
|
| Function call
V
MCUBoot user API
========================== RESTART ======================
MCUboot engine parse flash, validate new image, if there is any, and move it around to the primary slot
|
|
V Function call, never returns
Reset_Handler of new image
BR,
Tamas
From: TF-M <tf-m-bounces(a)lists.trustedfirmware.org> On Behalf Of Suresh Marisetty via TF-M
Sent: 2021. május 25., kedd 16:16
To: Andrew Thoelke <Andrew.Thoelke(a)arm.com>; tf-m(a)lists.trustedfirmware.org
Cc: nd <nd(a)arm.com>
Subject: Re: [TF-M] Firmware update API - MCUboot update
Hi Andrew,
I am thinking of two paths for the update client application: one through MCUBoot and another direct to the FWU interface. MCUBoot path is for legacy application compatibility purpose. Longer term, I am wondering if MCUBoot is needed.
In embedded there is always a challenge to optimize the code size as space in storage is limited and any optimization to remove redundancies will help.
Update client application
|
| Function call
V V
MCUBoot user API |
Shim layer |
| |
| Function call |
V |
FWU API <------------|
|
| TF-M psa_call() etc.
V
FWU Partition
|
| Function call
V
MCUBoot user API
MCUBoot engine
MCUBoot image size is around 60K and
thanks
Suresh Marisetty
Infineon Semiconductor Corporation
From: Andrew Thoelke <Andrew.Thoelke(a)arm.com<mailto:Andrew.Thoelke@arm.com>>
Sent: Tuesday, May 25, 2021 1:39 AM
To: Marisetty Suresh (CYSC CSS ICW SW SSE) <Suresh.Marisetty(a)infineon.com<mailto:Suresh.Marisetty@infineon.com>>; tf-m(a)lists.trustedfirmware.org<mailto:tf-m@lists.trustedfirmware.org>
Cc: nd <nd(a)arm.com<mailto:nd@arm.com>>
Subject: RE: Firmware update API - MCUboot update
Caution: This e-mail originated outside Infineon Technologies. Do not click on links or open attachments unless you validate it is safe<https://goto.infineon.com/SocialEngineering>.
Hi Suresh,
> I am of the belief that MCUboot will be a very thin shim layer over the FWU API to provide the compatibility interface to legacy software and most of the work that was done earlier in MCUboot is pushed down into the FWU partition.
Are you suggesting that the software stack might look like this:
Update client application
|
| Function call
V
MCUBoot user API
Shim layer
|
| Function call
V
FWU API
|
| TF-M psa_call() etc.
V
FWU Partition
|
| Function call
V
MCUBoot user API
MCUBoot engine
This looks like it has one more layer than it needs, as either:
1. The Update client application could Talk directly to the FWU API, or
2. The first MCUBoot user API could interact with an MCUBoot update partition (RoT Service), without having to tunnel the MCUBoot API over the FWU API. The latter might not be straightforward - I am not sure that anyone has reviewed the two APIs for this purpose.
Are you only considering this software stack for a system where touching the update client application source code is not possible (needed for option #1 above)? - and you also cannot introduce a custom MCUBoot RoT Service partition (option #2 above) so you want to reuse TF-M's existing FWU API and partition?
Regards,
Andrew
From: TF-M <tf-m-bounces(a)lists.trustedfirmware.org<mailto:tf-m-bounces@lists.trustedfirmware.org>> On Behalf Of Suresh Marisetty via TF-M
Sent: 25 May 2021 02:37
To: Sherry Zhang <Sherry.Zhang2(a)arm.com<mailto:Sherry.Zhang2@arm.com>>; tf-m(a)lists.trustedfirmware.org<mailto:tf-m@lists.trustedfirmware.org>
Cc: nd <nd(a)arm.com<mailto:nd@arm.com>>
Subject: Re: [TF-M] Firmware update API - MCUboot update
Hi Sherry,
Thanks for the info. Wondering if there is some documentation or powerpoint explaining how the MCUBoot is changed to accommodate the FWU API.
Details that would help:
1. How the MCUboot works without the FWU API - natively
2. How the MCUBoot needs to be modified to leverage from FWU API
3. What components are retained in MCUBoot ex: image format, signing, metadata, tools
I am of the belief that MCUboot will be a very thin shim layer over the FWU API to provide the compatibility interface to legacy software and most of the work that was done earlier in MCUboot is pushed down into the FWU partition.
The other way to look at it is: If somebody wants to replace MCUboot with a simple BL to integrate it tightly into TFM, what would that look like?
thanks
Suresh Marisetty
Infineon Semiconductor Corporation
From: Sherry Zhang <Sherry.Zhang2(a)arm.com<mailto:Sherry.Zhang2@arm.com>>
Sent: Thursday, May 13, 2021 7:51 PM
To: Marisetty Suresh (CYSC CSS ICW SW SSE) <Suresh.Marisetty(a)infineon.com<mailto:Suresh.Marisetty@infineon.com>>; tf-m(a)lists.trustedfirmware.org<mailto:tf-m@lists.trustedfirmware.org>
Cc: nd <nd(a)arm.com<mailto:nd@arm.com>>
Subject: RE: Firmware update API - MCUboot update
Caution: This e-mail originated outside Infineon Technologies. Do not click on links or open attachments unless you validate it is safe<https://goto.infineon.com/SocialEngineering>.
Hi Suresh,
The MCUboot update functionality is about validating the existing images on the device which is different from that of the firmware update service which follows mostly with the PSA Firmware Update API spec<https://developer.arm.com/documentation/ihi0093/latest/>.
We designed a shim layer between the firmware update partition and bootloader. A specific bootloader can be ported into the firmware update partition via that shim layer. Please refer to the firmware update service document<https://git.trustedfirmware.org/TF-M/trusted-firmware-m.git/tree/docs/techn…>. In the MCUboot based shim layer implementation, it calls some user/public APIs provided by MCUboot to achieve its functionality. For example, the Firmware Update API spec describes that psa_fwu_install() API should validate the image or defer the validation to a system reboot. In the MCUboot shim layer implementation, it calls the boot_write_magic() API to mark the image as a candidate image for MCUboot and defers the image validation to a system reboot. Please refer to this link<https://git.trustedfirmware.org/TF-M/trusted-firmware-m.git/tree/secure_fw/…>.
Can you please provide more specific suggestion or questions?
Regards,
Sherry Zhang
From: Suresh.Marisetty(a)infineon.com<mailto:Suresh.Marisetty@infineon.com> <Suresh.Marisetty(a)infineon.com<mailto:Suresh.Marisetty@infineon.com>>
Sent: Thursday, May 13, 2021 11:40 PM
To: Sherry Zhang <Sherry.Zhang2(a)arm.com<mailto:Sherry.Zhang2@arm.com>>; tf-m(a)lists.trustedfirmware.org<mailto:tf-m@lists.trustedfirmware.org>
Cc: nd <nd(a)arm.com<mailto:nd@arm.com>>
Subject: RE: Firmware update API - MCUboot update
Hi Sherry,
Please take a closer look at the MCUboot and TFM might want to have a clear position/distinction between these two and how to transition from MCUboot update to this mechanism or it could be that they complement each other.
thanks
Suresh Marisetty
Infineon Semiconductor Corporation
From: Sherry Zhang <Sherry.Zhang2(a)arm.com<mailto:Sherry.Zhang2@arm.com>>
Sent: Wednesday, May 12, 2021 8:55 PM
To: Marisetty Suresh (CYSC CSS ICW SW SSE) <Suresh.Marisetty(a)infineon.com<mailto:Suresh.Marisetty@infineon.com>>; tf-m(a)lists.trustedfirmware.org<mailto:tf-m@lists.trustedfirmware.org>
Cc: nd <nd(a)arm.com<mailto:nd@arm.com>>
Subject: RE: Firmware update API - MCUboot update
Caution: This e-mail originated outside Infineon Technologies. Do not click on links or open attachments unless you validate it is safe<https://goto.infineon.com/SocialEngineering>.
Hi Suresh,
The firmware update service APIs are for updating the firmware. The functionalities of these APIs includes loading the image into its target device(flash), verifying the image and installing it and so on.
The user can call the these APIs to achieve update images. For example, in the integration of TF-M and the FreeRTOS OTA<https://github.com/Linaro/amazon-freertos/blob/tfm-fwu/libraries/abstractio…>, the OTA agent calls the firmware update service APIs to achieve an image update remotely.
I guess that the "MCUboot update services" you mentioned refers to the functionality of MCUboot which acts as a bootloader. As a bootloader, it can verify the image which already exists on the device and chose the right image to start up. But it cannot, for example, load the image into device or control the image update process.
The firmware update partition calls some user APIs provided by MCUboot to cooperate with it. You can refer to https://git.trustedfirmware.org/TF-M/trusted-firmware-m.git/tree/docs/techn….
Regards,
Sherry Zhang
From: TF-M <tf-m-bounces(a)lists.trustedfirmware.org<mailto:tf-m-bounces@lists.trustedfirmware.org>> On Behalf Of Suresh Marisetty via TF-M
Sent: Thursday, May 13, 2021 11:09 AM
To: tf-m(a)lists.trustedfirmware.org<mailto:tf-m@lists.trustedfirmware.org>
Subject: [TF-M] Firmware update API - MCUboot update
Hi,
I would like to see if there is any guidance/documentation on how to coordinate between the firmware update services API with that of MCUboot.
Does the use of this API make the MCUboot update services redundant?
thanks
Suresh Marisetty
Infineon Semiconductor Corporation
Lead Member of Technical Staff
CYSC CSS ICW SW SSE
Mobile: +5103863997
Suresh.Marisetty(a)infineon.com<mailto:Suresh.Marisetty@infineon.com>
Hi,
To better maintain tf-m documentation, we plan to enable 'turn warnings into errors' in documentation HTML generation. The patch<https://review.trustedfirmware.org/c/TF-M/trusted-firmware-m/+/10424> is on review now.
One note is that sphinx should be updated to 2.0.1, otherwise there will be some 'duplicate label' warnings, which will fail documentation generation.
Best Regards,
Summer
Hi,
Please consider separating the configuration files from the scripts/tools. That would enable re-using the scripts in other projects.
I.e. if the .clang-format file lives in the tf-m repo, then the script running clang-format could be used with multiple repositories.
/George
From: TF-M <tf-m-bounces(a)lists.trustedfirmware.org> On Behalf Of Salome Thirot via TF-M
Sent: 28 June 2021 11:42
To: tf-m(a)lists.trustedfirmware.org
Subject: [TF-M] Static check framework for TF-M
Hi all,
Hugo L'Hostis and I have written a series of patches to enable various checks that can be done locally before committing the code, they will be added in the tf-m-tools repository. The patches are the following, any comment is welcome:
cppcheck:
https://review.trustedfirmware.org/c/TF-M/tf-m-tools/+/10009/8
clang-format:
https://review.trustedfirmware.org/c/TF-M/tf-m-tools/+/10463/2
copyright headers:
https://review.trustedfirmware.org/c/TF-M/tf-m-tools/+/10464/2
Regards,
Salome
This is the "good practice" to add prefixes to global names.
From: TF-M <tf-m-bounces(a)lists.trustedfirmware.org> On Behalf Of Xinyu Zhang
via TF-M
Sent: Thursday, June 24, 2021 12:00 PM
To: tf-m(a)lists.trustedfirmware.org
Cc: nd <nd(a)arm.com>
Subject: [TF-M] Remove Customized Region Name Prefix in Linker Scripts
Hi,
The existing linker definitions abuse prefixes such as ER_ and TFM_. Some
names do not have a clear scope, which reduces the readability.
Here are some patches to address the problem:
* Patch 10383
<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Freview.tr
ustedfirmware.org%2Fc%2FTF-M%2Ftrusted-firmware-m%2F%2B%2F10383&data=04%7C01
%7Candrey.butok%40nxp.com%7C8c57174d86d447802a4908d936f6d729%7C686ea1d3bc2b4
c6fa92cd99c5c301635%7C0%7C0%7C637601256068960339%7CUnknown%7CTWFpbGZsb3d8eyJ
WIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata
=G8Jf5YT4mptpeBUw8U7YkVbSKGvgXXtC3G8wRBqbJvY%3D&reserved=0> :
TFM_UNPRIV_CODE --> UNPRIV_CODE
* Patch 10384
<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Freview.tr
ustedfirmware.org%2Fc%2FTF-M%2Ftrusted-firmware-m%2F%2B%2F10384&data=04%7C01
%7Candrey.butok%40nxp.com%7C8c57174d86d447802a4908d936f6d729%7C686ea1d3bc2b4
c6fa92cd99c5c301635%7C0%7C0%7C637601256068970289%7CUnknown%7CTWFpbGZsb3d8eyJ
WIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata
=BSU1cXFeV61T48OO68FHJVFxD4tnSHz%2FmndTUSWjLOE%3D&reserved=0> :
TFM_SP_LOAD_LIST --> SP_LOAD_LIST
* Patch 10385
<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Freview.tr
ustedfirmware.org%2Fc%2FTF-M%2Ftrusted-firmware-m%2F%2B%2F10385&data=04%7C01
%7Candrey.butok%40nxp.com%7C8c57174d86d447802a4908d936f6d729%7C686ea1d3bc2b4
c6fa92cd99c5c301635%7C0%7C0%7C637601256068970289%7CUnknown%7CTWFpbGZsb3d8eyJ
WIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata
=PYVkbSu05KgbqdUk%2FdCC7MAAg3KoNPKYXA4C1PrdnK0%3D&reserved=0> : TFM_SECURE_*
--> SECURE_*
Please help to put comments and inform us if your platforms couple tightly
with the symbols defined in LD.
Thanks,
Xinyu
HI,
Having no declared topics for the forum, let's discuss the PSA Audit and TF-M logs features and scope to avoid possible confusion.
Thanks and best regards,
Anton
From: TF-M <tf-m-bounces(a)lists.trustedfirmware.org> On Behalf Of Anton Komlev via TF-M
Sent: Wednesday, June 16, 2021 4:07 PM
To: tf-m(a)lists.trustedfirmware.org
Cc: nd <nd(a)arm.com>
Subject: [TF-M] Technical Forum call - June 24
Hi,
The next Technical Forum is planned on Thursday, June 24 7:00-8:00 UTC (Asia time zone).
Please reply on this email with your proposals for agenda topics.
Recording and slides of previous meetings are here:
https://www.trustedfirmware.org/meetings/tf-m-technical-forum/
Best regards,
Anton
Hello Team:
Audit Logging is a requirement for a number of e2e security schemes including Microsoft Azure. The implementation may need a bit of use case specific or customer steering to get back on track to demonstrating it will fit the bill for e2e usage. I would think carefully about the strategy here because I fully expect that the moment it is deprecated a business need for it to exist will be raised. Please carefully consider how to add support back in quickly if it is deprecated now, though I would personally like to see it retained.
All the best!
Reed
From: TF-M <tf-m-bounces(a)lists.trustedfirmware.org> on behalf of Andrej Butok via TF-M <tf-m(a)lists.trustedfirmware.org>
Reply-To: Andrej Butok <andrey.butok(a)nxp.com>
Date: Wednesday, June 16, 2021 at 5:56 AM
To: Ken Liu <Ken.Liu(a)arm.com>
Cc: "tf-m(a)lists.trustedfirmware.org" <tf-m(a)lists.trustedfirmware.org>
Subject: Re: [TF-M] Deprecate 'partitions/audit_logging' and its related tests
Hi Ken
> Or any doubts about depreciating it?
It is not used because its implementation is not finished, the current implementation is only for PSA L1 and not supported by IPC. This is not enough for certification.
The Log service is optimally required by the PSA Certification.
If you going to deprecate it, first delete the requirement from the PSA L2&L3 Certification profiles.
Thanks,
Andrej
From: TF-M <tf-m-bounces(a)lists.trustedfirmware.org> On Behalf Of Ken Liu via TF-M
Sent: Wednesday, June 16, 2021 10:46 AM
To: tf-m(a)lists.trustedfirmware.org
Cc: nd <nd(a)arm.com>
Subject: [TF-M] Deprecate 'partitions/audit_logging' and its related tests
Hi,
The component name under this folder is ‘Audit logging’, and:
* There is no explicit specification or requirements for it, and its functionality is as a simple log collector (and looks no one is using it).
* It supported under the library model only. And it is meaningless to move to IPC because of this.
* It costs extra maintenance effort in test cases and partition code.
So a plan is to deprecate this folder and its related test cases; will create a new one when the specification or requirements are explicitly defined.
Question here is:
Anyone is using this service? Or any doubts about depreciating it?
Will collect the response and broadcast it at 25th Jun.
Thanks.
/Ken
