- TF-A - lists.trustedfirmware.org

Re: [TF-A] fconf: Validating config data

by Madhukar Pappireddy

Hi Raghu, We had a discussion internally about handling the mandatory and optional properties in fconf and we believe we can use the following approach. Please let us know if it is acceptable to you. As agreed over the mailing list, we treat the scenarios of a missing/incorrect mandatory property or a structurally bad dtb as an integration error and must lead to panic in runtime. It is the responsibility of the developer providing the populate callback to detect and return an error code in such scenarios. It will be treated as an unrecoverable error and further escalated to panic() by the fconf framework itself. An incorrect or missing optional property in a dtb should lead to a warning message and the boot loader should continue after assigning a default value to the specific property. Further, every property accessed by a populate callback should be clearly defined as either mandatory or optional in a fconf based binding document such as the one shown here [1]. This must be enforced in spirit as part of the code review process. We believe the callbacks can be categorized into two: Generic vs platform-specific. Generic callbacks are the ones that are required to support a standard component supported by platforms running TF-A such as TBBR, SDEI, IO Policy, GICv3, etc. Platform-specific callbacks are provided by platform developers to work with non-standard components such as a Proprietary Hardware IP. The binding document for generic populate callbacks should be provided by the TF-A project. The generic binding will become a contract for the platforms to implement the support for integrating standard components and hence, will be platform agnostic. Correspondingly, it is the responsibility of the platform developer to provide the binding for platform-specific populate callbacks. Any thoughts? [1] https://trustedfirmware-a.readthedocs.io/en/latest/components/fconf/fconf_p… Thanks, Madhukar -----Original Message----- From: TF-A <tf-a-bounces(a)lists.trustedfirmware.org> On Behalf Of Manish Badarkhe via TF-A Sent: Wednesday, May 20, 2020 6:00 AM To: Raghu K <raghu.ncstate(a)icloud.com>; Sandrine Bailleux <Sandrine.Bailleux(a)arm.com>; tf-a(a)lists.trustedfirmware.org; Louis Mayencourt <Louis.Mayencourt(a)arm.com> Cc: nd <nd(a)arm.com> Subject: Re: [TF-A] fconf: Validating config data Hi Raghu We have plan to work on this and come up with some design which handles mandatory/critical properties. On 13/05/2020, 22:18, "TF-A on behalf of Raghu K via TF-A" <tf-a-bounces(a)lists.trustedfirmware.org on behalf of tf-a(a)lists.trustedfirmware.org> wrote: Hi All, Since the 2.3 release is done, can we revisit this topic? I think we left this with finalizing on how to handle bad/incorrect DTB's. Sandrine's latest proposal below: "A bad DTB seems more like an integration error than a programming error to me, and thus should be handled with runtime checks according to the current guidelines. Incorrect values for mandatory properties should probably be treated as unrecoverable errors (causing a panic) and incorrect/missing optional properties as recoverable errors (issuing a warning message)." I agree with this proposal and think we should follow this. This addresses my original concern of handling errors consistently and being safe by verifying mandatory/critical properties at run-time. Thoughts ? Thanks Raghu On 4/13/20 10:27 AM, Raghu Krishnamurthy wrote: > Thanks Sandrine. Revisiting after v2.3 is sounds fine. > > -Raghu > > On 4/10/20 2:25 AM, Sandrine Bailleux wrote: >> Hi Raghu, >> >> On 4/8/20 12:50 AM, Raghu Krishnamurthy wrote: >>> Thanks Sandrine, Louis, >>> >>> Agree with both of you. I'm fine with using asserts or panics, as >>> long as we uniformly use it. The change i sent out(review 3845) was >>> because i noticed inconsistency in handling errors. If we do use >>> asserts, all code that checks for mandatory properties, should be >>> changed to assert as opposed to return error code. For optional >>> properties, we can continue to return an error code or print >>> warnings etc. >> >> Yes, I too think consistency is key here. As you said, we need to >> settle on the expected behaviour and enforce it uniformly across the >> fconf code. Let's revisit this code after the v2.3 release. >> >>> I would like to point out that using asserts here is different from >>> what is documented in the coding guidelines. The guidelines >>> explicitly spells out using asserts for "programming errors". >>> Now, is having a bad DTB considered a programming error? ;) The DTB >>> is platform data as opposed to code. The guidelines might need to be >>> updated based on the conclusion here. >> >> Now that you point it out, and after taking a closer look at [1], I >> think I was wrong. A bad DTB seems more like an integration error >> than a programming error to me, and thus should be handled with >> runtime checks according to the current guidelines. Incorrect values >> for mandatory properties should probably be treated as unrecoverable >> errors (causing a panic) and incorrect/missing optional properties as >> recoverable errors (issuing a warning message). >> >> [1] >> https://trustedfirmware-a.readthedocs.io/en/latest/process/coding-guideline… >> >> >>> Also note the couple of scenarios i mentioned in an earlier email. >>> Platforms like RPI4 don't generally enable TBBR and the DTB image >>> could get corrupt or be modified on purpose. On a release build, >>> this could cause silent corruption. Panic() would avoid this. >>> >>> In any case, it would be good to settle on the expected behavior for >>> each of these abnormal cases. I don't have a strong preference for >>> asserts or panics here, since each has its pros and cons as both of >>> you called out. >>> >>> Thanks >>> Raghu > -- TF-A mailing list TF-A(a)lists.trustedfirmware.org https://lists.trustedfirmware.org/mailman/listinfo/tf-a -- TF-A mailing list TF-A(a)lists.trustedfirmware.org https://lists.trustedfirmware.org/mailman/listinfo/tf-a

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TF-A Tech Forum Agenda @ Thr 18th June 2020 16:00-1700 BST

by Joanna Farley

Hi All, The next TF-A Tech Forum is scheduled for Thu 18th June 2020 16:00 – 17:00 (BST). A reoccurring meeting invite has been sent out to the subscribers of this TF-A mailing list. If you don’t have this please let me know. Note the new time that is an hour earlier then previous sessions. Agenda: * TF-A Unit Level Testing - Presented by Lauren Wehrmeister * General explanation of the new approach for Unit Testing in TF-A. * Optional TF-A Mailing List Topic Discussions If TF-A contributors have anything they wish to present at any future TF-A tech forum please contact me to have that scheduled. Thanks Joanna

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Re: [TF-A] Upgrading libfdt library

by Madhukar Pappireddy

Hi Alexei, To be clear, my current effort is to upgrade the libfdt source files in TF-A. I am not sure why the libfdt source was not integrated into TF-A as a preloaded source tree similar to MbedTLS. Perhaps, any TF-A veteran can help answer this question? Since there is an ongoing effort in the TF-A project to move to CMake build framework, I did not plan to integrate libfdt Makefile into TF-A. Hi Yann, Between commits aadd0b6 (the current version in TF-A for libfdt files) and 85e5d83, I have noticed bug fixes, code cleanups. I am not familiar with the dtc project. I can push a WIP patch with libfdt source files picked from commit 85e5d83. Please let me know if you see any issues with ST platforms. Thanks, Madhukar -----Original Message----- From: TF-A <tf-a-bounces(a)lists.trustedfirmware.org> On Behalf Of Yann GAUTIER via TF-A Sent: Monday, June 15, 2020 10:26 AM To: tf-a(a)lists.trustedfirmware.org Subject: Re: [TF-A] Upgrading libfdt library Hi Madhukar, We had seen some issue on STM32MP1 with the previous libfdt rebase, that led to the ticket [1]. And then a partial revert [2]. I'll then try this new version to check if boot time doesn't increase too much. Do you expect other changes than the one changing __ASSEMBLY__ to __ASSEMBLER__? And maybe some updates in libfdt.mk file? If you push this new version to gerrit, it will be easier to fetch and test, as a WIP if it is better for you? Regards, Yann [1] https://github.com/ARM-software/tf-issues/issues/643 [2] https://github.com/ARM-software/arm-trusted-firmware/commit/00f588bf2cc5298… On 6/15/20 2:18 PM, Alexei Fedorov via TF-A wrote: > Hi Madhukar, > > I'm wondering why we need to integrate libfdt sources in TF-A? Why > cannot we use the same option as for MbedTls when the build system > gets the path to the preloaded source tree? > > Regards. > > Alexei > > ---------------------------------------------------------------------- > -- > *From:* TF-A <tf-a-bounces(a)lists.trustedfirmware.org> on behalf of > Varun Wadekar via TF-A <tf-a(a)lists.trustedfirmware.org> > *Sent:* 13 June 2020 01:04 > *To:* Madhukar Pappireddy <Madhukar.Pappireddy(a)arm.com> > *Cc:* tf-a(a)lists.trustedfirmware.org <tf-a(a)lists.trustedfirmware.org> > *Subject:* Re: [TF-A] Upgrading libfdt library > > Hi Madhukar, > > Before we merge this change, can you please explain how we arrived at > this specific version? Are we tracking the stable version of the library? > > What would be the testing criteria before merging the library? Does > tftf provide any tests that can act as a smoking gun? > > Does it make sense to ask platform owners to test the specific version > you plan to merge? This way we would have more confidence in the library. > > -Varun > > *From:* TF-A <tf-a-bounces(a)lists.trustedfirmware.org> *On Behalf Of > *Madhukar Pappireddy via TF-A > *Sent:* Friday, June 12, 2020 4:48 PM > *To:* tf-a(a)lists.trustedfirmware.org > *Subject:* [TF-A] Upgrading libfdt library > > *External email: Use caution opening links or attachments* > > Hello, > > I am planning to upgrade libfdt library source files in TF-A. They > haven’t been updated for a while. As the project moves towards > improving the fconf framework and adding more properties in device > tree source files, we rely more on libfdt APIs. I have done some > preliminary investigation to check if there is any performance penalty > in upgrading the libfdt source files integrated into TF-A from the > current version(which corresponds to commit aadd0b6 in the dtc repo > [1]) to master commit (85e5d83). I have run some basics tests on both > x86 and > aarch64 machines and I have not seen any performance degradation. I > plan to push a patch shortly to integrate the latest version of libfdt > files in TF-A. > > Please let me know if you are aware of any performance issues or have > other concerns. > > [1] https://git.kernel.org/pub/scm/utils/dtc/dtc.git > > Thanks, > > Madhu > > -- TF-A mailing list TF-A(a)lists.trustedfirmware.org https://lists.trustedfirmware.org/mailman/listinfo/tf-a

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Re: [TF-A] Upgrading libfdt library

by Yann GAUTIER

Hi Madhukar, We had seen some issue on STM32MP1 with the previous libfdt rebase, that led to the ticket [1]. And then a partial revert [2]. I'll then try this new version to check if boot time doesn't increase too much. Do you expect other changes than the one changing __ASSEMBLY__ to __ASSEMBLER__? And maybe some updates in libfdt.mk file? If you push this new version to gerrit, it will be easier to fetch and test, as a WIP if it is better for you? Regards, Yann [1] https://github.com/ARM-software/tf-issues/issues/643 [2] https://github.com/ARM-software/arm-trusted-firmware/commit/00f588bf2cc5298… On 6/15/20 2:18 PM, Alexei Fedorov via TF-A wrote: > Hi Madhukar, > > I'm wondering why we need to integrate libfdt sources in TF-A? Why > cannot we use the same option as for MbedTls when the build system gets > the path to the preloaded source tree? > > Regards. > > Alexei > > ------------------------------------------------------------------------ > *From:* TF-A <tf-a-bounces(a)lists.trustedfirmware.org> on behalf of Varun > Wadekar via TF-A <tf-a(a)lists.trustedfirmware.org> > *Sent:* 13 June 2020 01:04 > *To:* Madhukar Pappireddy <Madhukar.Pappireddy(a)arm.com> > *Cc:* tf-a(a)lists.trustedfirmware.org <tf-a(a)lists.trustedfirmware.org> > *Subject:* Re: [TF-A] Upgrading libfdt library > > Hi Madhukar, > > Before we merge this change, can you please explain how we arrived at > this specific version? Are we tracking the stable version of the library? > > What would be the testing criteria before merging the library? Does tftf > provide any tests that can act as a smoking gun? > > Does it make sense to ask platform owners to test the specific version > you plan to merge? This way we would have more confidence in the library. > > -Varun > > *From:* TF-A <tf-a-bounces(a)lists.trustedfirmware.org> *On Behalf Of > *Madhukar Pappireddy via TF-A > *Sent:* Friday, June 12, 2020 4:48 PM > *To:* tf-a(a)lists.trustedfirmware.org > *Subject:* [TF-A] Upgrading libfdt library > > *External email: Use caution opening links or attachments* > > Hello, > > I am planning to upgrade libfdt library source files in TF-A. They > haven’t been updated for a while. As the project moves towards improving > the fconf framework and adding more properties in device tree source > files, we rely more on libfdt APIs. I have done some preliminary > investigation to check if there is any performance penalty in upgrading > the libfdt source files integrated into TF-A from the current > version(which corresponds to commit aadd0b6 in the dtc repo [1]) to > master commit (85e5d83). I have run some basics tests on both x86 and > aarch64 machines and I have not seen any performance degradation. I plan > to push a patch shortly to integrate the latest version of libfdt files > in TF-A. > > Please let me know if you are aware of any performance issues or have > other concerns. > > [1] https://git.kernel.org/pub/scm/utils/dtc/dtc.git > > Thanks, > > Madhu > >

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Re: [TF-A] Upgrading libfdt library

by Alexei Fedorov

Hi Madhukar, I'm wondering why we need to integrate libfdt sources in TF-A? Why cannot we use the same option as for MbedTls when the build system gets the path to the preloaded source tree? Regards. Alexei ________________________________ From: TF-A <tf-a-bounces(a)lists.trustedfirmware.org> on behalf of Varun Wadekar via TF-A <tf-a(a)lists.trustedfirmware.org> Sent: 13 June 2020 01:04 To: Madhukar Pappireddy <Madhukar.Pappireddy(a)arm.com> Cc: tf-a(a)lists.trustedfirmware.org <tf-a(a)lists.trustedfirmware.org> Subject: Re: [TF-A] Upgrading libfdt library Hi Madhukar, Before we merge this change, can you please explain how we arrived at this specific version? Are we tracking the stable version of the library? What would be the testing criteria before merging the library? Does tftf provide any tests that can act as a smoking gun? Does it make sense to ask platform owners to test the specific version you plan to merge? This way we would have more confidence in the library. -Varun From: TF-A <tf-a-bounces(a)lists.trustedfirmware.org> On Behalf Of Madhukar Pappireddy via TF-A Sent: Friday, June 12, 2020 4:48 PM To: tf-a(a)lists.trustedfirmware.org Subject: [TF-A] Upgrading libfdt library External email: Use caution opening links or attachments Hello, I am planning to upgrade libfdt library source files in TF-A. They haven’t been updated for a while. As the project moves towards improving the fconf framework and adding more properties in device tree source files, we rely more on libfdt APIs. I have done some preliminary investigation to check if there is any performance penalty in upgrading the libfdt source files integrated into TF-A from the current version(which corresponds to commit aadd0b6 in the dtc repo [1]) to master commit (85e5d83). I have run some basics tests on both x86 and aarch64 machines and I have not seen any performance degradation. I plan to push a patch shortly to integrate the latest version of libfdt files in TF-A. Please let me know if you are aware of any performance issues or have other concerns. [1] https://git.kernel.org/pub/scm/utils/dtc/dtc.git Thanks, Madhu

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Re: [TF-A] Question on confine_index_array.h import in tf-a

by Sandrine Bailleux

Hello Etienne, On 6/10/20 1:19 PM, Etienne Carriere via TF-A wrote: > Dear all, > > As part of a patchset series review (topic scmi-msg), change [1] > imports confine_array_index.h header file from OP-TEE OS repository. > The file originates from the open source Fuschia project, see link in > commit message of [1]. > > As being imported for external packages, the header file inherits > Fushca and OP-TEE notices. > The helper function can protect some data structure from side channel > attacks leveraging index indirect access overflows during speculative > execution. > It is not Arm copyright. It is BSD-3-Clause license. > I'll add an entry in the docs/license.rst for the file. > > Where to locate the file? > It is ok to add such a file in include/common? > Does it deserve a specific lib path, like > include/lib/speculconfie_array_index.h? > Maybe add as include/lib/cpus/confine_array_index.h as it is CPU > speculative matters? Before we discuss the location of this header file, have we considered using the compiler support for speculative execution mitigations instead? I am referring to the __builtin_speculation_safe_value() macro, which I believe achieves the same goal as the code you propose to introduce here, i.e. protecting against Spectre v1 bounds-check bypass attacks. TF-A already uses this compiler builtin today and provides a wrapper macro around it, see SPECULATION_SAFE_VALUE() in include/lib/utils_def.f (although I would argue this is not the best location one could think of...). For reference, this was introduced by commit [1]. According to Arm's whitepaper [2], the support for this compiler builtin was added in GCC 9 and LLVM/Clang was to follow shortly. If these versions are too recent for you, then I believe the official location to get equivalent code is [3]. As stated there: The header file provided here allows a migration path to using the builtin function for users who are unable to immediately upgrade to a compiler which supports the builtin. So I would prefer we get the code from there rather than from the OP-TEE project, which got it from the Fuschia project ;) This is licensed under the Boost Software License 1.0, which we've never used in TF-A so I would need to check with our legal department whether this is OK, but I don't expect any issues there as this is described as a permissive license only requiring preservation of copyright and license notices. This is assuming that both header files (the one from OP-TEE and the one from the Arm software Github repo) are equivalent... Is this the case? Is the code provided in OP-TEE perhaps more optimized? Regards, Sandrine [1] https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git/commit/?id=9edd… [2] https://developer.arm.com/support/arm-security-updates/speculative-processo… [3] https://github.com/ARM-software/speculation-barrier

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Invitation: TF-A Tech Forum @ Every 2 weeks from 16:00 to 17:00 on Thursday (BST) (tf-a@lists.trustedfirmware.org)

by Bill Fletcher

You have been invited to the following event. Title: TF-A Tech Forum We run an open technical forum call for anyone to participate and it is not restricted to Trusted Firmware project members. It will operate under the guidance of the TF TSC. Feel free to forward this invite to colleagues. Invites are via the TF-A mailing list and also published on the Trusted Firmware website. Details are here: https://www.trustedfirmware.org/meetings/tf-a-technical-forum/Tr… Firmware is inviting you to a scheduled Zoom meeting.Join Zoom Meetinghttps://zoom.us/j/9159704974Meeting ID: 915 970 4974One tap mobile+16465588656,,9159704974# US (New York)+16699009128,,9159704974# US (San Jose)Dial by your location        +1 646 558 8656 US (New York)        +1 669 900 9128 US (San Jose)        877 853 5247 US Toll-free        888 788 0099 US Toll-freeMeeting ID: 915 970 4974Find your local number: https://zoom.us/u/ad27hc6t7h   When: Every 2 weeks from 16:00 to 17:00 on Thursday United Kingdom Time Calendar: tf-a(a)lists.trustedfirmware.org Who: * Bill Fletcher- creator * tf-a(a)lists.trustedfirmware.org Event details: https://www.google.com/calendar/event?action=VIEW&eid=NWlub3Ewdm1tMmk1cTJrM… Invitation from Google Calendar: https://www.google.com/calendar/ You are receiving this courtesy email at the account tf-a(a)lists.trustedfirmware.org because you are an attendee of this event. To stop receiving future updates for this event, decline this event. Alternatively, you can sign up for a Google Account at https://www.google.com/calendar/ and control your notification settings for your entire calendar. Forwarding this invitation could allow any recipient to send a response to the organiser and be added to the guest list, invite others regardless of their own invitation status or to modify your RSVP. Learn more at https://support.google.com/calendar/answer/37135#forwarding

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Upgrading libfdt library

by Madhukar Pappireddy

Hello, I am planning to upgrade libfdt library source files in TF-A. They haven't been updated for a while. As the project moves towards improving the fconf framework and adding more properties in device tree source files, we rely more on libfdt APIs. I have done some preliminary investigation to check if there is any performance penalty in upgrading the libfdt source files integrated into TF-A from the current version(which corresponds to commit aadd0b6 in the dtc repo [1]) to master commit (85e5d83). I have run some basics tests on both x86 and aarch64 machines and I have not seen any performance degradation. I plan to push a patch shortly to integrate the latest version of libfdt files in TF-A. Please let me know if you are aware of any performance issues or have other concerns. [1] https://git.kernel.org/pub/scm/utils/dtc/dtc.git Thanks, Madhu

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Re: [TF-A] ATF LTS version

by Varun Wadekar

Hello Matteo, Apologies for still using an outdated term. I have trained myself to get used to "TF-A" - looks like I am still not there. >> The idea has also been just raised to the Trusted Firmware project Board for initial consideration and we will be all very keen to understand how much interest there is from the wider TF-A community of adopters and external (non-Arm) maintainers That is good to hear. For the exact scope, I think we can assume the usual expectations from any LTS software stack - stability, performance, security, bug fixes along with maintenance support. We are open to discussing the cadence and any other operational commitments. @Francois, from the description of Trusted Substrate looks like you also expect the sub-projects to provide LTS versions for the project as a whole to succeed (?) -Varun -----Original Message----- From: TF-A <tf-a-bounces(a)lists.trustedfirmware.org> On Behalf Of Matteo Carlini via TF-A Sent: Thursday, June 11, 2020 4:25 AM To: tf-a(a)lists.trustedfirmware.org Subject: Re: [TF-A] ATF LTS version External email: Use caution opening links or attachments Hi Francois, > I'd be happy to know more about what you see as TFA LTS: exact scope, number of versions, duration, operational commitments (zero-day...). > Do you have other firmware LTS needs? Agree. That’s precisely what I was hinting to Varun, when mentioning concrete requirements for the LTS scheme. > Trusted Substrate is the aggregation of { TFA, OP-TEE, some TEE apps such as firmwareTPM, U-Boot }. > Trusted Substrate effort is led by Linaro members and is going to be set up as a more open project. First time I heard about it. Good to know, but I guess we'll need to discuss the intersection and collaboration with the Trusted Firmware project at some point. Having a LTS versioning scheme for the Trusted Firmware hosted projects should be theoretically either in the scope of the Project itself or, if the Board agrees, appointed to some other project/entity. > Our end goal is to enable unified, transactional, robust (anti-bricking, anti rollback) UEFI OTA on both U-Boot and EDK2. Fair, but IMHO this has little to do with Arm Secure world software LTS releases (TF-A/Hafnium/OP-TEE/TAs, TF-M)...probably best to discuss aside, this is not in scope of what Varun is raising. Thanks Matteo -- TF-A mailing list TF-A(a)lists.trustedfirmware.org https://lists.trustedfirmware.org/mailman/listinfo/tf-a

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Re: [TF-A] ATF LTS version

by Joanna Farley

I should also mention the Release processes we follow and the attempt to indicated the deprecation of interfaces in advance in the effort to maintain compatibility https://trustedfirmware-a.readthedocs.io/en/latest/about/release-informatio… On 11/06/2020, 14:47, "TF-A on behalf of Joanna Farley via TF-A" <tf-a-bounces(a)lists.trustedfirmware.org on behalf of tf-a(a)lists.trustedfirmware.org> wrote: Hi Varun, I guess this suggestion came in response to last weeks Tech Forum discussion from a question about experiences people had from migrating to different TF-A tagged releases. In general we try and keep the tip of Master at tagged release quality through an extensive CI system ran on each patch. I appreciate this CI is currently a little opaque to many contributors as this is still in the process of being transitioned to the OpenCI hosted by Trustedfirmware.org servers which will be visible to all. As mentioned in the recent "Overview of the TF-A v2.3 Release" presentation on https://www.trustedfirmware.org/meetings/tf-a-technical-forum/ the additional testing done for a 6 monthly tagged release is quite minimal and the larger work is ensuring all documentation is up to date. Additionally all new features are generally behind their own build flags but I appreciate it is some work for a tagged release to be absorbed into product offerings. I asked at the tech forum last week what more we could do to allow releases to be integrated more easily. On the call it was requested if we could disable weak bindings to symbols so it could be more easily seen where platform decisions may need to be made and we will look into this. If there are any more adjustments to the way tagged releases are produced please let us know. One thing that had been considered briefly was the production of a security bug only branch that was maintained only between 6 month tagged releases before being replaced by the next security bug only branch based on the next 6 month release but that has not progressed very far as a proposal as until your email here it was perceived to not be in demand. A LTS branch is a larger endeavour as it sounds like something that includes more than security fixes and I look forward to you elaborating more as Matteo requests. Thanks Joanna On 11/06/2020, 12:19, "Matteo Carlini via TF-A" <tf-a(a)lists.trustedfirmware.org> wrote: Hi Varun, Thanks for raising this topic (but please do embrace the official terminology “TF-A”…we never really promoted ATF and it's also absolutely outdated now 😉 ). Arm has received different queries over time on supporting Trusted Firmware LTS releases, but the effort to sustain them is something that the Arm engineering team alone cannot really afford and commit to (either in the TF-A or TF-M space). The idea has also been just raised to the Trusted Firmware project Board for initial consideration and we will be all very keen to understand how much interest there is from the wider TF-A community of adopters and external (non-Arm) maintainers, so to evaluate the possibility of a more concrete proposal to be carried on within the community Project. I guess it will also be good to start by elaborating more concretely on the requirements that you would like to see in an hypothetical LTS versioning scheme. Thanks Matteo > From: TF-A <tf-a-bounces(a)lists.trustedfirmware.org> On Behalf Of Varun Wadekar via TF-A > Sent: 10 June 2020 22:47 > To: tf-a(a)lists.trustedfirmware.org > Subject: [TF-A] ATF LTS version > > Hello team, > > To extend the discussion around version upgrades from our last call, I would like to understand if there is enough interest around generating a LTS version of the TF-A to alleviate the pain. > > For NVIDIA, this would be helpful as it streamlines the upgrade path for our devices in the field. The LTS version will guarantee security fixes, bug fixes, stability fixes for the longer term and we won’t have to upgrade the entire firmware to get these goodies. > > It would be interesting to see what OEMs and maintainers think about this? Has this been discussed at tf.org or Arm internally? > > -Varun -- TF-A mailing list TF-A(a)lists.trustedfirmware.org https://lists.trustedfirmware.org/mailman/listinfo/tf-a -- TF-A mailing list TF-A(a)lists.trustedfirmware.org https://lists.trustedfirmware.org/mailman/listinfo/tf-a

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Re: [TF-A] ATF LTS version

by Joanna Farley

Hi Varun, I guess this suggestion came in response to last weeks Tech Forum discussion from a question about experiences people had from migrating to different TF-A tagged releases. In general we try and keep the tip of Master at tagged release quality through an extensive CI system ran on each patch. I appreciate this CI is currently a little opaque to many contributors as this is still in the process of being transitioned to the OpenCI hosted by Trustedfirmware.org servers which will be visible to all. As mentioned in the recent "Overview of the TF-A v2.3 Release" presentation on https://www.trustedfirmware.org/meetings/tf-a-technical-forum/ the additional testing done for a 6 monthly tagged release is quite minimal and the larger work is ensuring all documentation is up to date. Additionally all new features are generally behind their own build flags but I appreciate it is some work for a tagged release to be absorbed into product offerings. I asked at the tech forum last week what more we could do to allow releases to be integrated more easily. On the call it was requested if we could disable weak bindings to symbols so it could be more easily seen where platform decisions may need to be made and we will look into this. If there are any more adjustments to the way tagged releases are produced please let us know. One thing that had been considered briefly was the production of a security bug only branch that was maintained only between 6 month tagged releases before being replaced by the next security bug only branch based on the next 6 month release but that has not progressed very far as a proposal as until your email here it was perceived to not be in demand. A LTS branch is a larger endeavour as it sounds like something that includes more than security fixes and I look forward to you elaborating more as Matteo requests. Thanks Joanna On 11/06/2020, 12:19, "Matteo Carlini via TF-A" <tf-a(a)lists.trustedfirmware.org> wrote: Hi Varun, Thanks for raising this topic (but please do embrace the official terminology “TF-A”…we never really promoted ATF and it's also absolutely outdated now 😉 ). Arm has received different queries over time on supporting Trusted Firmware LTS releases, but the effort to sustain them is something that the Arm engineering team alone cannot really afford and commit to (either in the TF-A or TF-M space). The idea has also been just raised to the Trusted Firmware project Board for initial consideration and we will be all very keen to understand how much interest there is from the wider TF-A community of adopters and external (non-Arm) maintainers, so to evaluate the possibility of a more concrete proposal to be carried on within the community Project. I guess it will also be good to start by elaborating more concretely on the requirements that you would like to see in an hypothetical LTS versioning scheme. Thanks Matteo > From: TF-A <tf-a-bounces(a)lists.trustedfirmware.org> On Behalf Of Varun Wadekar via TF-A > Sent: 10 June 2020 22:47 > To: tf-a(a)lists.trustedfirmware.org > Subject: [TF-A] ATF LTS version > > Hello team, > > To extend the discussion around version upgrades from our last call, I would like to understand if there is enough interest around generating a LTS version of the TF-A to alleviate the pain. > > For NVIDIA, this would be helpful as it streamlines the upgrade path for our devices in the field. The LTS version will guarantee security fixes, bug fixes, stability fixes for the longer term and we won’t have to upgrade the entire firmware to get these goodies. > > It would be interesting to see what OEMs and maintainers think about this? Has this been discussed at tf.org or Arm internally? > > -Varun -- TF-A mailing list TF-A(a)lists.trustedfirmware.org https://lists.trustedfirmware.org/mailman/listinfo/tf-a

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Re: [TF-A] ATF LTS version

by Matteo Carlini

Hi Francois, > I'd be happy to know more about what you see as TFA LTS: exact scope, number of versions, duration, operational commitments (zero-day...). > Do you have other firmware LTS needs? Agree. That’s precisely what I was hinting to Varun, when mentioning concrete requirements for the LTS scheme. > Trusted Substrate is the aggregation of { TFA, OP-TEE, some TEE apps such as firmwareTPM, U-Boot }. > Trusted Substrate effort is led by Linaro members and is going to be set up as a more open project. First time I heard about it. Good to know, but I guess we'll need to discuss the intersection and collaboration with the Trusted Firmware project at some point. Having a LTS versioning scheme for the Trusted Firmware hosted projects should be theoretically either in the scope of the Project itself or, if the Board agrees, appointed to some other project/entity. > Our end goal is to enable unified, transactional, robust (anti-bricking, anti rollback) UEFI OTA on both U-Boot and EDK2. Fair, but IMHO this has little to do with Arm Secure world software LTS releases (TF-A/Hafnium/OP-TEE/TAs, TF-M)...probably best to discuss aside, this is not in scope of what Varun is raising. Thanks Matteo

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Re: [TF-A] ATF LTS version

by Matteo Carlini

Hi Varun, Thanks for raising this topic (but please do embrace the official terminology “TF-A”…we never really promoted ATF and it's also absolutely outdated now 😉 ). Arm has received different queries over time on supporting Trusted Firmware LTS releases, but the effort to sustain them is something that the Arm engineering team alone cannot really afford and commit to (either in the TF-A or TF-M space). The idea has also been just raised to the Trusted Firmware project Board for initial consideration and we will be all very keen to understand how much interest there is from the wider TF-A community of adopters and external (non-Arm) maintainers, so to evaluate the possibility of a more concrete proposal to be carried on within the community Project. I guess it will also be good to start by elaborating more concretely on the requirements that you would like to see in an hypothetical LTS versioning scheme. Thanks Matteo > From: TF-A <tf-a-bounces(a)lists.trustedfirmware.org> On Behalf Of Varun Wadekar via TF-A > Sent: 10 June 2020 22:47 > To: tf-a(a)lists.trustedfirmware.org > Subject: [TF-A] ATF LTS version > > Hello team, > > To extend the discussion around version upgrades from our last call, I would like to understand if there is enough interest around generating a LTS version of the TF-A to alleviate the pain. > > For NVIDIA, this would be helpful as it streamlines the upgrade path for our devices in the field. The LTS version will guarantee security fixes, bug fixes, stability fixes for the longer term and we won’t have to upgrade the entire firmware to get these goodies. > > It would be interesting to see what OEMs and maintainers think about this? Has this been discussed at tf.org or Arm internally? > > -Varun

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Re: [TF-A] ATF LTS version

by François Ozog

Hi Varun, There are early discussions in Linaro on what would mean setting up "Collaborative LTS" for what we call Trusted Substrate (see below signature). I'd be happy to know more about what you see as TFA LTS: exact scope, number of versions, duration, operational commitments (zero-day...). Do you have other firmware LTS needs? Cheers François-Frédéric Ozog Linaro Trusted Substrate is the aggregation of { TFA, OP-TEE, some TEE apps such as firmwareTPM, U-Boot }. Trusted Substrate effort is led by Linaro members and is going to be set up as a more open project. Our end goal is to enable unified, transactional, robust (anti-bricking, anti rollback) UEFI OTA on both U-Boot and EDK2. On Wed, 10 Jun 2020 at 23:47, Varun Wadekar via TF-A < tf-a(a)lists.trustedfirmware.org> wrote: > Hello team, > > > > To extend the discussion around version upgrades from our last call, I > would like to understand if there is enough interest around generating a > LTS version of the TF-A to alleviate the pain. > > > > For NVIDIA, this would be helpful as it streamlines the upgrade path for > our devices in the field. The LTS version will guarantee security fixes, > bug fixes, stability fixes for the longer term and we won’t have to upgrade > the entire firmware to get these goodies. > > > > It would be interesting to see what OEMs and maintainers think about this? > Has this been discussed at tf.org or Arm internally? > > > > -Varun > -- > TF-A mailing list > TF-A(a)lists.trustedfirmware.org > https://lists.trustedfirmware.org/mailman/listinfo/tf-a > -- François-Frédéric Ozog | *Director Linaro Edge & Fog Computing Group* T: +33.67221.6485 francois.ozog(a)linaro.org | Skype: ffozog

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Updated invitation with note: TF-A Tech Forum @ Every 2 weeks from 17:00 to 18:00 on Thursday from Thu 26 Mar to Wed 17 Jun (GMT) (tf-a@lists.trustedfirmware.org)

by Bill Fletcher

This event has been changed with this note: "Starting 18th June, the TF-A Tech Forum will be moved earlier by 1 hour to 1600 UK time (1500 UTC). This change is to avoid overlapping the TF Technical Steering Committee call. A new invite will be posted to the TF-A mailing list and on the trustedfirmware.org website." Title: TF-A Tech Forum We run an open technical forum call for anyone to participate and it is not restricted to Trusted Firmware project members. It will operate under the guidance of the TF TSC. Feel free to forward this invite to colleagues. Invites are via the TF-A mailing list and also published on the Trusted Firmware website. Details are here: https://www.trustedfirmware.org/meetings/tf-a-technical-forum/Tr… Firmware is inviting you to a scheduled Zoom meeting.Join Zoom Meetinghttps://zoom.us/j/9159704974Meeting ID: 915 970 4974One tap mobile+16465588656,,9159704974# US (New York)+16699009128,,9159704974# US (San Jose)Dial by your location        +1 646 558 8656 US (New York)        +1 669 900 9128 US (San Jose)        877 853 5247 US Toll-free        888 788 0099 US Toll-freeMeeting ID: 915 970 4974Find your local number: https://zoom.us/u/ad27hc6t7h   When: Every 2 weeks from 17:00 to 18:00 on Thursday from Thu 26 Mar to Wed 17 Jun United Kingdom Time (changed) Where: Zoom Calendar: tf-a(a)lists.trustedfirmware.org Who: (Guest list has been hidden at organiser's request) Event details: https://www.google.com/calendar/event?action=VIEW&eid=N3ZoNDBuZzZnM2k4cGszY… Invitation from Google Calendar: https://www.google.com/calendar/ You are receiving this courtesy email at the account tf-a(a)lists.trustedfirmware.org because you are an attendee of this event. To stop receiving future updates for this event, decline this event. Alternatively, you can sign up for a Google Account at https://www.google.com/calendar/ and control your notification settings for your entire calendar. Forwarding this invitation could allow any recipient to send a response to the organiser and be added to the guest list, invite others regardless of their own invitation status or to modify your RSVP. Learn more at https://support.google.com/calendar/answer/37135#forwarding

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Updated invitation with note: TF-A Tech Forum @ Every 2 weeks from 17:00 to 18:00 on Thursday from Thu 7 May to Wed 17 Jun (BST) (tf-a@lists.trustedfirmware.org)

by Bill Fletcher

This event has been changed with this note: "Starting 18th June, the TF-A Tech Forum will be moved earlier by 1 hour to 1600 UK time (1500 UTC). This change is to avoid overlapping the TF Technical Steering Committee call. A new invite will be posted to the TF-A mailing list and on the trustedfirmware.org website." Title: TF-A Tech Forum We run an open technical forum call for anyone to participate and it is not restricted to Trusted Firmware project members. It will operate under the guidance of the TF TSC. Feel free to forward this invite to colleagues. Invites are via the TF-A mailing list and also published on the Trusted Firmware website. Details are here: https://www.trustedfirmware.org/meetings/tf-a-technical-forum/Tr… Firmware is inviting you to a scheduled Zoom meeting.Join Zoom Meetinghttps://zoom.us/j/9159704974Meeting ID: 915 970 4974One tap mobile+16465588656,,9159704974# US (New York)+16699009128,,9159704974# US (San Jose)Dial by your location        +1 646 558 8656 US (New York)        +1 669 900 9128 US (San Jose)        877 853 5247 US Toll-free        888 788 0099 US Toll-freeMeeting ID: 915 970 4974Find your local number: https://zoom.us/u/ad27hc6t7h   When: Every 2 weeks from 17:00 to 18:00 on Thursday from Thu 7 May to Wed 17 Jun United Kingdom Time (changed) Where: Zoom Calendar: tf-a(a)lists.trustedfirmware.org Who: (Guest list has been hidden at organiser's request) Event details: https://www.google.com/calendar/event?action=VIEW&eid=N3ZoNDBuZzZnM2k4cGszY… Invitation from Google Calendar: https://www.google.com/calendar/ You are receiving this courtesy email at the account tf-a(a)lists.trustedfirmware.org because you are an attendee of this event. To stop receiving future updates for this event, decline this event. Alternatively, you can sign up for a Google Account at https://www.google.com/calendar/ and control your notification settings for your entire calendar. Forwarding this invitation could allow any recipient to send a response to the organiser and be added to the guest list, invite others regardless of their own invitation status or to modify your RSVP. Learn more at https://support.google.com/calendar/answer/37135#forwarding

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Cancelled event: TF-A Tech Forum @ (BST) (tf-a@lists.trustedfirmware.org)

by Bill Fletcher

This event has been cancelled. Title: TF-A Tech Forum We run an open technical forum call for anyone to participate and it is not restricted to Trusted Firmware project members. It will operate under the guidance of the TF TSC. Feel free to forward this invite to colleagues. Invites are via the TF-A mailing list and also published on the Trusted Firmware website. Details are here: https://www.trustedfirmware.org/meetings/tf-a-technical-forum/Tr… Firmware is inviting you to a scheduled Zoom meeting.Join Zoom Meetinghttps://zoom.us/j/9159704974Meeting ID: 915 970 4974One tap mobile+16465588656,,9159704974# US (New York)+16699009128,,9159704974# US (San Jose)Dial by your location        +1 646 558 8656 US (New York)        +1 669 900 9128 US (San Jose)        877 853 5247 US Toll-free        888 788 0099 US Toll-freeMeeting ID: 915 970 4974Find your local number: https://zoom.us/u/ad27hc6t7h   When: United Kingdom Time Where: Zoom Calendar: tf-a(a)lists.trustedfirmware.org Who: (Guest list has been hidden at organiser's request) Invitation from Google Calendar: https://www.google.com/calendar/ You are receiving this courtesy email at the account tf-a(a)lists.trustedfirmware.org because you are an attendee of this event. To stop receiving future updates for this event, decline this event. Alternatively, you can sign up for a Google Account at https://www.google.com/calendar/ and control your notification settings for your entire calendar. Forwarding this invitation could allow any recipient to send a response to the organiser and be added to the guest list, invite others regardless of their own invitation status or to modify your RSVP. Learn more at https://support.google.com/calendar/answer/37135#forwarding

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Re-scheduling TF-A Tech Forum earlier by 1 hour

by Bill Fletcher

Hi all, Starting 18th June, the TF-A Tech Forum will be moved earlier by 1 hour to 1600 UK time (1500 UTC). This change is to avoid overlapping with the TF Technical Steering Committee call. We'll delete the existing invite and send a new one to this list. Regards Bill -- [image: Linaro] <http://www.linaro.org/> *Bill Fletcher* | *Field Engineering* T: +44 7833 498336 <+44+7833+498336> bill.fletcher(a)linaro.org | Skype: billfletcher2020

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ATF LTS version

by Varun Wadekar

Hello team, To extend the discussion around version upgrades from our last call, I would like to understand if there is enough interest around generating a LTS version of the TF-A to alleviate the pain. For NVIDIA, this would be helpful as it streamlines the upgrade path for our devices in the field. The LTS version will guarantee security fixes, bug fixes, stability fixes for the longer term and we won't have to upgrade the entire firmware to get these goodies. It would be interesting to see what OEMs and maintainers think about this? Has this been discussed at tf.org or Arm internally? -Varun

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Measured Boot in TF-A

by Alexei Fedorov

Hello all, The initial patch for Measured Boot has been split into 5 separates buildable ones: https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/3806 https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/4473 https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/4508 https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/4509 https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/4510 and are ready for review/merge. The design follows "TF-A Design Notes for Measured Boot" document . The number of API changes and code modifications based on the received feedback were made, and the most important are: 1. TPM hash algorithm is now independent from the one used by Trusted Boot and can be set separately to a different value. 2. Size of Event Log is passed as a driver build option and can be tuned to meet platform specific requirements (debug/release, number of images loaded, etc.). 3. Driver accepts platform specific table of images to be loaded/measured. 4. PCR index to use for TMP records is passed in platform specific table (see above) and can be set individually for each image. Regards. Alexei

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Question on confine_index_array.h import in tf-a

by Etienne Carriere

Dear all, As part of a patchset series review (topic scmi-msg), change [1] imports confine_array_index.h header file from OP-TEE OS repository. The file originates from the open source Fuschia project, see link in commit message of [1]. As being imported for external packages, the header file inherits Fushca and OP-TEE notices. The helper function can protect some data structure from side channel attacks leveraging index indirect access overflows during speculative execution. It is not Arm copyright. It is BSD-3-Clause license. I'll add an entry in the docs/license.rst for the file. Where to locate the file? It is ok to add such a file in include/common? Does it deserve a specific lib path, like include/lib/speculconfie_array_index.h? Maybe add as include/lib/cpus/confine_array_index.h as it is CPU speculative matters? Could you help [1] review to progress? [1] https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/4055 Regards, Etienne

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Re: [TF-A] RK3399_BAUDRATE default value

by Hugh Cole-Baker

> On 6 Jun 2020, at 17:52, Heiko Stübner via TF-A <tf-a(a)lists.trustedfirmware.org> wrote: > > Hi Walter, > > Am Freitag, 5. Juni 2020, 22:45:25 CEST schrieb Walter Lozano via TF-A: >> I have noticed that default baudrate for rk3399 board RK3399_BAUDRATE >> defined in plat/rockchip/rk3399/rk3399_def.h is 115200 while U-boot >> default value and most documentation points to a value of 1500000 for >> console. > > console baudrate on rk3399 differ a lot between boards. There are a > number using the 1.5MHz and another big number using 115200 > (including but not limited to the ChromeOS devices from the Gru line). > > Hence we have the code that selects the actual baudrate from the > devicetree attached by u-boot when calling TF-A. > > So I guess it should stay as it is right now. On the RK3399 there are currently a couple of roadblocks preventing this selection of the baudrate from the devicetree from working. Firstly in U-Boot, SPL_ATF_NO_PLATFORM_PARAM is forced on when selecting ROCKCHIP_RK3399 in Kconfig [1]. Secondly in TF-A the 64K buffer used to store the passed devicetree isn't large enough to fit some of the RK3399 device tree blobs, as I found when removing SPL_ATF_NO_PLATFORM_PARAM from U-Boot. I guess the issue in TF-A needs to be fixed first before passing the platform parameter can be enabled in U-Boot, I've submitted a TF-A patch to increase the buffer size [2]. [1]: https://gitlab.denx.de/u-boot/u-boot/-/blob/61853a7ac7e167d90899ec4e99d2e07… [2]: https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/4512 > Heiko > > >> This of course means that messages printed by ATF are not visible by >> default in this context. >> >> The change from 1500000 to 115200 was introduced in >> 0c05748bdebfad9fa43a80962186438bb8fbce62, >> >> https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git/commit/?id=0c05… >> >> with the following message >> >> commit 0c05748bdebfad9fa43a80962186438bb8fbce62 >> Author: Caesar Wang <wxt(a)rock-chips.com> >> Date: Tue Apr 19 20:42:17 2016 +0800 >> >> rockchip: fixes for the required >> >> This patch has the following change for rk3399. >> >> * Set the uart to 115200 since the loader decide to set >> uart baud to 115200Hz. So the ATF also should set uart baud to 115200. >> [..] >> >> However, I'm not sure it this still applies. >> >> I'll be happy to submit a patch to update the value if it is OK. >> >> Regards, >> >> Walter >> >> > > > > > -- > TF-A mailing list > TF-A(a)lists.trustedfirmware.org > https://lists.trustedfirmware.org/mailman/listinfo/tf-a

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Re: [TF-A] GICV3: system interface EOI ordering RFC

by Raghu Krishnamurthy

Hello, Sorry for chiming in late. Are we sure that the msr/mrs to the GICv3 EOI register is not a context synchronizing event or ensures ordering itself ? Also did the addition of DSB() fix the issue ? If yes, can you try adding a delay or a few NOP's/dummy instructions or an ISB to see if the issue goes away? We need to know the right thing to do architecturally and confirm that the issue is really due to reordering at the core before adding the DSB. Adding a DSB might be masking a timing issue. -Raghu On 6/8/20 4:47 AM, Sandeep Tripathy via TF-A wrote: >> -----Original Message----- >> From: Soby Mathew [mailto:Soby.Mathew@arm.com] >> Sent: Monday, June 08, 2020 3:36 PM >> To: Sandeep Tripathy; Olivier Deprez; tf-a(a)lists.trustedfirmware.org >> Cc: nd >> Subject: RE: [TF-A] GICV3: system interface EOI ordering RFC >> >> Just some inputs from my side: >> I agree we need at least a dsb() after the write to MMIO region to silence >> the >> peripheral and before the EOI at GIC sysreg interface. Adding it to the >> GIC EOI > > Thanks for the confirmation. Now it’s about choosing the right place. > >> API seems the logical thing to do but as Olivier mentions, there are >> interrupt >> handler which do not deal with MMIO (eg: the Systimer interrupt) so adding >> it >> to GICv3 API might be arduous for such handlers. >> >> So there is a choice here to let the interrupt handlers to deal with >> ensuring >> completeness before EOI at sysreg interface or adding it to GICv3 EOI API >> and >> take the overhead for interrupt handlers which do not have to deal with >> MMIO. >> > > Yes I feel either of these is a must to guarantee functionality > architecturally though > both approach end up with some unnecessary overhead. > > If GICv3 api takes care then it is an overhead for some ISRs dealing with > non-MMIO. > At present I do not see an active use case in reference implementation where > sys timer > ISR is in a performance intensive path where one additional DSB will be > perceivable. > But there may be some I could be totally wrong in this assumption (pmu/debug > or.. not sure). > Whereas I can certainly imagine some MMIO ISRs in performance critical path > where unnecessary > DSB is not acceptable at all. > > If the interrupt handler needs to ensure then it will generically add 'DSB' > as I think > the driver cannot and should not make assumptions about how EOI is done > afterwards. > That will be overhead for the ISRs dealing with MMIO peripherals and non > GIC-v3. > If we consider only GICv3+ then good. Otherwise I would prefer the > 'plat_ic_end_of_interrupt' > like Olivier mentioned with a #if GICv3 instead of each ISRs dealing with > it. > >> The GICv3 legacy MMIO CPU interface is deprecated for TF-A and the sys >> interface is the only one GICv3 driver in TF-A supports. > > Right we can ignore the GICv3 legacy mode but GICv2 will still remain ? > >> >> Best Regards >> Soby Mathew >> > > Thanks > Sandeep > >>> -----Original Message----- >>> From: TF-A <tf-a-bounces(a)lists.trustedfirmware.org> On Behalf Of Sandeep >>> Tripathy via TF-A >>> Sent: 08 June 2020 10:34 >>> To: Olivier Deprez <Olivier.Deprez(a)arm.com>; tf- >> a(a)lists.trustedfirmware.org >>> Subject: Re: [TF-A] GICV3: system interface EOI ordering RFC >>> >>> Hi Olivier, >>>> -----Original Message----- >>>> From: Olivier Deprez [mailto:Olivier.Deprez@arm.com] >>>> Sent: Monday, June 08, 2020 1:14 PM >>>> To: tf-a(a)lists.trustedfirmware.org; Sandeep Tripathy >>>> Subject: Re: [TF-A] GICV3: system interface EOI ordering RFC >>>> >>>> Hi Sandeep, >>>> >>>> gicv3_end_of_interrupt_sel1 is a static access helper macro. Its >>>> naming precisely tells what it does at gicv3 module level. It is >>>> called from >>> the weak >>>> plat_ic_end_of_interrupt function for BL32 image. >>>> >>>> I tend to think it is the driver responsibility to ensure the module >>> interrupt >>>> acknowledge register write is reaching HW in order (or "be visible to >>> all >>>> observers"). >>> >>> The driver should be agnostic of what interrupt controller is used and >>> its >>> behavior. >>> And since 'all' writes were to mmio ranges mapped Device(nGnRE) >>> /strongly-ordered(nGnRnE) >>> there was no such need. This is a special case for GICv3 system >>> interface only. >>> Adding at driver level a DSB is unnecessary for other interrupt >>> controllers. >>> >>>> Also I suspect adding a dsb might not be required generically for all >>> kind of IP. >>> >>> Here are you referring to the peripheral IP or interrupt controller IP ? >>> The issue is reordering at arm core itself (STR to device address Vs >>> msr(sysreg >>> write)). >>> So I think Its applicable for all IP. >>> >>>> Adding a barrier in generic code might incur an unnecessary >>>> bottleneck. >>> >>> But if there is a need to *ensure* presence of at least one DSB between >>> the >>> write transfer from core to device clear and gicv3 eoi icc register >>> write in a >>> generic way then what other option we have. >>>> >>>> Thus wouldn't it be better to add the barrier to the overridden >>>> platform function rather than in generic gicv3 code? >>> >>> That can be done but I feel this is more to do with gicv3 system >>> interface only. >>> Inside plat_xxx one has to check #if GICV3 ...and system interface. >>>> >>>> I have a put a comment in the review, we can continue the discussion >>> there. >>>> >>>> Regards, >>>> Olivier. >>>> >>> Thanks >>> Sandeep >>>> ________________________________________ >>>> From: TF-A <tf-a-bounces(a)lists.trustedfirmware.org> on behalf of >>>> Sandeep Tripathy via TF-A <tf-a(a)lists.trustedfirmware.org> >>>> Sent: 05 June 2020 19:43 >>>> To: tf-a(a)lists.trustedfirmware.org >>>> Subject: [TF-A] GICV3: system interface EOI ordering RFC >>>> >>>> Hi, >>>> In a typical interrupt handling sequence we do 1-Read IAR >>>> 2-Do interrupt handling >>>> 3-Clear the interrupt at source , so that the device de-asserts IRQ >>> request to >>>> GIC >>>> >> I am suggesting a need of DSB here in case of GICv3 +. >>>> 4-Write to GIC cpu interface to do EOI. >>>> >>>> Till GICv2 and with GICv3 legacy interface ICC_EOI write is a write >>>> over >>> AMBA >>>> interface. The >>>> Addresses are mapped with (nR) attribute. Hence the write transfers >>> from the >>>> core will be >>>> generated at step 3 and 4 in order. Please ignore the additional >>> buffers/bridges >>>> in path from >>>> core till peripheral which has to be dealt separately as per SOC. >>>> >>>> Query: I understand GICv3 system interface accesses are not over this >>> protocol >>>> and core will not >>>> follow the ordering rule ? >>>> >>>> I have observed spurious interrupt issue/manifestation ( I don't have >>> the >>>> transfers probed) in >>>> RTOS environment where I have a primitive GICv3 driver but I wonder >>>> why things does not fail in Linux or tf-a. If it is working because >>>> from step(3) to >>> step(4) we have >>>> barriers by chace >>>> due to other device register writes then I would suggest to have one >>>> in >>> the EOI >>>> clearing API itself. >>>> >>>> RFC: >>> https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/4454 >>>> >>>> Thanks >>>> Sandeep >>> -- >>> TF-A mailing list >>> TF-A(a)lists.trustedfirmware.org >>> https://lists.trustedfirmware.org/mailman/listinfo/tf-a

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Re: [TF-A] GICV3: system interface EOI ordering RFC

by Sandeep Tripathy

> -----Original Message----- > From: Soby Mathew [mailto:Soby.Mathew@arm.com] > Sent: Monday, June 08, 2020 3:36 PM > To: Sandeep Tripathy; Olivier Deprez; tf-a(a)lists.trustedfirmware.org > Cc: nd > Subject: RE: [TF-A] GICV3: system interface EOI ordering RFC > > Just some inputs from my side: > I agree we need at least a dsb() after the write to MMIO region to silence > the > peripheral and before the EOI at GIC sysreg interface. Adding it to the > GIC EOI Thanks for the confirmation. Now it’s about choosing the right place. > API seems the logical thing to do but as Olivier mentions, there are > interrupt > handler which do not deal with MMIO (eg: the Systimer interrupt) so adding > it > to GICv3 API might be arduous for such handlers. > > So there is a choice here to let the interrupt handlers to deal with > ensuring > completeness before EOI at sysreg interface or adding it to GICv3 EOI API > and > take the overhead for interrupt handlers which do not have to deal with > MMIO. > Yes I feel either of these is a must to guarantee functionality architecturally though both approach end up with some unnecessary overhead. If GICv3 api takes care then it is an overhead for some ISRs dealing with non-MMIO. At present I do not see an active use case in reference implementation where sys timer ISR is in a performance intensive path where one additional DSB will be perceivable. But there may be some I could be totally wrong in this assumption (pmu/debug or.. not sure). Whereas I can certainly imagine some MMIO ISRs in performance critical path where unnecessary DSB is not acceptable at all. If the interrupt handler needs to ensure then it will generically add 'DSB' as I think the driver cannot and should not make assumptions about how EOI is done afterwards. That will be overhead for the ISRs dealing with MMIO peripherals and non GIC-v3. If we consider only GICv3+ then good. Otherwise I would prefer the 'plat_ic_end_of_interrupt' like Olivier mentioned with a #if GICv3 instead of each ISRs dealing with it. > The GICv3 legacy MMIO CPU interface is deprecated for TF-A and the sys > interface is the only one GICv3 driver in TF-A supports. Right we can ignore the GICv3 legacy mode but GICv2 will still remain ? > > Best Regards > Soby Mathew > Thanks Sandeep > > -----Original Message----- > > From: TF-A <tf-a-bounces(a)lists.trustedfirmware.org> On Behalf Of Sandeep > > Tripathy via TF-A > > Sent: 08 June 2020 10:34 > > To: Olivier Deprez <Olivier.Deprez(a)arm.com>; tf- > a(a)lists.trustedfirmware.org > > Subject: Re: [TF-A] GICV3: system interface EOI ordering RFC > > > > Hi Olivier, > > > -----Original Message----- > > > From: Olivier Deprez [mailto:Olivier.Deprez@arm.com] > > > Sent: Monday, June 08, 2020 1:14 PM > > > To: tf-a(a)lists.trustedfirmware.org; Sandeep Tripathy > > > Subject: Re: [TF-A] GICV3: system interface EOI ordering RFC > > > > > > Hi Sandeep, > > > > > > gicv3_end_of_interrupt_sel1 is a static access helper macro. Its > > > naming precisely tells what it does at gicv3 module level. It is > > > called from > > the weak > > > plat_ic_end_of_interrupt function for BL32 image. > > > > > > I tend to think it is the driver responsibility to ensure the module > > interrupt > > > acknowledge register write is reaching HW in order (or "be visible to > > all > > > observers"). > > > > The driver should be agnostic of what interrupt controller is used and > > its > > behavior. > > And since 'all' writes were to mmio ranges mapped Device(nGnRE) > > /strongly-ordered(nGnRnE) > > there was no such need. This is a special case for GICv3 system > > interface only. > > Adding at driver level a DSB is unnecessary for other interrupt > > controllers. > > > > > Also I suspect adding a dsb might not be required generically for all > > kind of IP. > > > > Here are you referring to the peripheral IP or interrupt controller IP ? > > The issue is reordering at arm core itself (STR to device address Vs > > msr(sysreg > > write)). > > So I think Its applicable for all IP. > > > > > Adding a barrier in generic code might incur an unnecessary > > > bottleneck. > > > > But if there is a need to *ensure* presence of at least one DSB between > > the > > write transfer from core to device clear and gicv3 eoi icc register > > write in a > > generic way then what other option we have. > > > > > > Thus wouldn't it be better to add the barrier to the overridden > > > platform function rather than in generic gicv3 code? > > > > That can be done but I feel this is more to do with gicv3 system > > interface only. > > Inside plat_xxx one has to check #if GICV3 ...and system interface. > > > > > > I have a put a comment in the review, we can continue the discussion > > there. > > > > > > Regards, > > > Olivier. > > > > > Thanks > > Sandeep > > > ________________________________________ > > > From: TF-A <tf-a-bounces(a)lists.trustedfirmware.org> on behalf of > > > Sandeep Tripathy via TF-A <tf-a(a)lists.trustedfirmware.org> > > > Sent: 05 June 2020 19:43 > > > To: tf-a(a)lists.trustedfirmware.org > > > Subject: [TF-A] GICV3: system interface EOI ordering RFC > > > > > > Hi, > > > In a typical interrupt handling sequence we do 1-Read IAR > > > 2-Do interrupt handling > > > 3-Clear the interrupt at source , so that the device de-asserts IRQ > > request to > > > GIC > > > >> I am suggesting a need of DSB here in case of GICv3 +. > > > 4-Write to GIC cpu interface to do EOI. > > > > > > Till GICv2 and with GICv3 legacy interface ICC_EOI write is a write > > > over > > AMBA > > > interface. The > > > Addresses are mapped with (nR) attribute. Hence the write transfers > > from the > > > core will be > > > generated at step 3 and 4 in order. Please ignore the additional > > buffers/bridges > > > in path from > > > core till peripheral which has to be dealt separately as per SOC. > > > > > > Query: I understand GICv3 system interface accesses are not over this > > protocol > > > and core will not > > > follow the ordering rule ? > > > > > > I have observed spurious interrupt issue/manifestation ( I don't have > > the > > > transfers probed) in > > > RTOS environment where I have a primitive GICv3 driver but I wonder > > > why things does not fail in Linux or tf-a. If it is working because > > > from step(3) to > > step(4) we have > > > barriers by chace > > > due to other device register writes then I would suggest to have one > > > in > > the EOI > > > clearing API itself. > > > > > > RFC: > > https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/4454 > > > > > > Thanks > > > Sandeep > > -- > > TF-A mailing list > > TF-A(a)lists.trustedfirmware.org > > https://lists.trustedfirmware.org/mailman/listinfo/tf-a

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Re: [TF-A] GICV3: system interface EOI ordering RFC

by Soby Mathew

Just some inputs from my side: I agree we need atleast a dsb() after the write to MMIO region to silence the peripheral and before the EOI at GIC sysreg interface. Adding it to the GIC EOI API seems the logical thing to do but as Olivier mentions, there are interrupt handler which do not deal with MMIO (eg: the Systimer interrupt) so adding it to GICv3 API might be arduous for such handlers. So there is a choice here to let the interrupt handlers to deal with ensuring completeness before EOI at sysreg interface or adding it to GICv3 EOI API and take the overhead for interrupt handlers which do not have to deal with MMIO. The GICv3 legacy MMIO CPU interface is deprecated for TF-A and the sys interface is the only one GICv3 driver in TF-A supports. Best Regards Soby Mathew > -----Original Message----- > From: TF-A <tf-a-bounces(a)lists.trustedfirmware.org> On Behalf Of Sandeep > Tripathy via TF-A > Sent: 08 June 2020 10:34 > To: Olivier Deprez <Olivier.Deprez(a)arm.com>; tf-a(a)lists.trustedfirmware.org > Subject: Re: [TF-A] GICV3: system interface EOI ordering RFC > > Hi Olivier, > > -----Original Message----- > > From: Olivier Deprez [mailto:Olivier.Deprez@arm.com] > > Sent: Monday, June 08, 2020 1:14 PM > > To: tf-a(a)lists.trustedfirmware.org; Sandeep Tripathy > > Subject: Re: [TF-A] GICV3: system interface EOI ordering RFC > > > > Hi Sandeep, > > > > gicv3_end_of_interrupt_sel1 is a static access helper macro. Its > > naming precisely tells what it does at gicv3 module level. It is > > called from > the weak > > plat_ic_end_of_interrupt function for BL32 image. > > > > I tend to think it is the driver responsibility to ensure the module > interrupt > > acknowledge register write is reaching HW in order (or "be visible to > all > > observers"). > > The driver should be agnostic of what interrupt controller is used and its > behavior. > And since 'all' writes were to mmio ranges mapped Device(nGnRE) > /strongly-ordered(nGnRnE) > there was no such need. This is a special case for GICv3 system interface only. > Adding at driver level a DSB is unnecessary for other interrupt controllers. > > > Also I suspect adding a dsb might not be required generically for all > kind of IP. > > Here are you referring to the peripheral IP or interrupt controller IP ? > The issue is reordering at arm core itself (STR to device address Vs msr(sysreg > write)). > So I think Its applicable for all IP. > > > Adding a barrier in generic code might incur an unnecessary bottleneck. > > But if there is a need to *ensure* presence of at least one DSB between the > write transfer from core to device clear and gicv3 eoi icc register write in a > generic way then what other option we have. > > > > Thus wouldn't it be better to add the barrier to the overridden > > platform function rather than in generic gicv3 code? > > That can be done but I feel this is more to do with gicv3 system interface only. > Inside plat_xxx one has to check #if GICV3 ...and system interface. > > > > I have a put a comment in the review, we can continue the discussion > there. > > > > Regards, > > Olivier. > > > Thanks > Sandeep > > ________________________________________ > > From: TF-A <tf-a-bounces(a)lists.trustedfirmware.org> on behalf of > > Sandeep Tripathy via TF-A <tf-a(a)lists.trustedfirmware.org> > > Sent: 05 June 2020 19:43 > > To: tf-a(a)lists.trustedfirmware.org > > Subject: [TF-A] GICV3: system interface EOI ordering RFC > > > > Hi, > > In a typical interrupt handling sequence we do 1-Read IAR > > 2-Do interrupt handling > > 3-Clear the interrupt at source , so that the device de-asserts IRQ > request to > > GIC > > >> I am suggesting a need of DSB here in case of GICv3 +. > > 4-Write to GIC cpu interface to do EOI. > > > > Till GICv2 and with GICv3 legacy interface ICC_EOI write is a write > > over > AMBA > > interface. The > > Addresses are mapped with (nR) attribute. Hence the write transfers > from the > > core will be > > generated at step 3 and 4 in order. Please ignore the additional > buffers/bridges > > in path from > > core till peripheral which has to be dealt separately as per SOC. > > > > Query: I understand GICv3 system interface accesses are not over this > protocol > > and core will not > > follow the ordering rule ? > > > > I have observed spurious interrupt issue/manifestation ( I don't have > the > > transfers probed) in > > RTOS environment where I have a primitive GICv3 driver but I wonder > > why things does not fail in Linux or tf-a. If it is working because > > from step(3) to > step(4) we have > > barriers by chace > > due to other device register writes then I would suggest to have one > > in > the EOI > > clearing API itself. > > > > RFC: > https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/4454 > > > > Thanks > > Sandeep > -- > TF-A mailing list > TF-A(a)lists.trustedfirmware.org > https://lists.trustedfirmware.org/mailman/listinfo/tf-a

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