- boot-architecture - lists.linaro.org

by Francois Ozog

Hi, Following implementation (or work towards) of EBBR 1.0 + UEFI Secure boot + UEFI update capsule we learnt a lot. Here are some topics that may need some clarification on the EBBR specs and It looks timely to start working on EBBR evolution. 0.1 - EBBR goal May be a reassessment on the "for what" the specification is built. Following all the discussions with prominent industry players, I start to think that limiting the constraints to be EBBR compliant may become counter productive. There will be both EBBR non compliant and EBBR compliant systems. This is inevitable. But EBBR exist for a number of use cases in a number of markets. The value of EBBR is consistent behavior across those. Maximising number of EBBR compliant systems without stating use case parameters ( "why" and "for what") may not be the best goal. Out of things to be more explicit are supported secure boot flows (with/without shim+grub or direct). Some vendors require shim+grub while industry players want the exact opposite: nothing but UEFI. This drivers a number of requirements in terms of UEFI protocols needed 0.2 - normative text The normative section shall be stated clearly: is " 1.2. Guiding Principles" normative? IETF and ETSI have different language conventions to express absolutely mandated and various levels of optionality. This spec may be red by Telecom people or Linux people. Their interpretation may be erroneous on words such as "shall" (ETSI "SHALL" = "IETF "MUST"). The language need to be explicit. I - protective offsets EBBR 1.0 states in "4.1. Partitioning of Shared Storage" that "Automatic partitioning tools (e.g. an OS installer) must not create partitions within the first 1MiB of storage, or delete, move, or modify protective partition entries." StandaloneMM is 2.5MB by itself with U-Boot being over 1MB without the variable rework done and update capsules. 4MB seems the minimum. 8MB to get margin and 16MB for A/B scheme. EBBR same paragraph also states: "Automatic partitioning tools (e.g. an OS installer) must not create partitions within the first 1MiB of storage, or delete, move, or modify protective partition entries. Manual partitioning tools should provide warnings when modifying protective partitions or creating partitions within the first 1MiB." is it expected that Linaro upstreams changes in installation tools, partition tools to conform to this (with updated to be agreed minimum)? II - identifying partitions Having two EFI partitions defined with EFI_GUID need a precise behaviour defined: boot with first or boot with second. Shall we have a EFI_GUID_ALT defined for A/B partition schemes? If not, the BootXXX variables should be used as selector? We lean towards BootXXX variables and not defining a new GUID. But this would mean explicit behavior to be stated in case of lack of BootXXX. I think GPT volume mirroring should be used in conjunction with A/B: A/B to recover version failures with current hardware, surrounding software; mirroring to protect against storage failures. Is there any recommendation on mirrored EFI volumes handling ? III - 32 bits are there any 32 bits specific considerations to be added? IV - UEFI_RNG_PROTOCOL Following my view in 0) I think this shall be made mandatory Linaro has upstreamed this in U-Boot and started to implement additional hardware drivers. KASLR is thus functional in 64 bits and will be in 32bits. V - UEFI SecureBoot Following my view in 0) I think this shall be made mandatory UEFI SecureBoot is not mentioned in section 2.6 so we need to clarify what needs to be implemented. In particular, we need to implement EFI_LOAD_FILE2_PROTOCOL for initrd signature checking. VI - UEFI update capsules Following my view in 0) I think this shall be made mandatory Section 2.6 of UEFI spec 2.7 mentions At some point in time we will need to propose UEFI specification update for: - anti-bricking anti rollback expected behavior - abstract capsules for "start transaction", "commit", "rollback" when we will be dealing with system wide transactional updates. There is probably a lot to state here but I am just starting the discussion. VII - UEFI watchdog Following my view in 0) I think this shall be made mandatory In addition to its definition, it should also integrate consistent parameters to define total duration covered as well as number of failed consecutive updates to be triggered as well as how it is delivered (powercycle, NMI, secureIRQ...) Cheers -- François-Frédéric

6 years, 4 months

10
45
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[DTE] dynamic parts of device trees

by Heinrich Schuchardt

Hello Francois, in a previous post I already mentioned some device tree fix-ups that U-Boot is applying. One new fix-up I found is the "cpu-release-addr" property in CPU nodes if the "enable-method" is "spin-table". - Before seeing this I never imagined CPU nodes to be dynamically filled. I think for our DTE discussion on signed device trees it would be valuable to know which parts of the device-tree are dynamically created. Where would be a good location to collect this information? Would the topic of dynamic parts of device trees deserve two slides on our next meeting? Best regards Heinrich

6 years, 4 months

5
10
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Re: RFC: EBBR specification update

by Heinrich Schuchardt

On 5/20/20 7:49 PM, François Ozog wrote: > > > On Wed, 20 May 2020 at 19:30, Daniel Thompson > <daniel.thompson(a)linaro.org <mailto:daniel.thompson@linaro.org>> wrote: > > On Wed, May 20, 2020 at 07:00:53PM +0200, François Ozog wrote: > > On Wed, 20 May 2020 at 18:39, Daniel Thompson > <daniel.thompson(a)linaro.org <mailto:daniel.thompson@linaro.org>> > > wrote: > > > > > On Tue, May 19, 2020 at 03:29:01PM +0100, Grant Likely wrote: > > > > On 11/03/2020 16:42, Daniel Thompson wrote: > > > > > On Wed, Mar 11, 2020 at 01:42:36PM +0100, Francois Ozog wrote: > > > > > > We have the following cases: > > > > > > > > > > > > - FW compatible with GPT (I mean firmware can be searched > based on > > > > > > GUID partition) > > > > > > Ok > > > > > > > > > > > > - FW that uses offsets and can be positioned at LBA >= 33 > > > > > > Ok > > > > > > Need to define a protective partition >> > > > > > > - FW that uses offsets and can be positioned such that > space between > > > LBA-2 > > > > > > and LBA-33 is used. > > > > > > Ok in theory as the header states where the partition entries > > > location is > > > > > > specified in a GPT_HEADER "Starting LBA of array of partition > > > entries". > > > > > > Linux kernel properly loads the partition entries if we > push them > > > after > > > > > > 16MB. > > > > > > > > > > > > read_lba > <https://elixir.bootlin.com/linux/latest/ident/read_lba > > > >(state, > > > > > > le64_to_cpu < > > > https://elixir.bootlin.com/linux/latest/ident/le64_to_cpu > > > >(gpt->partition_entry_lba) > > > > > > > > > > > > But I bet 2 is hardcoded in many tools... > > > > > > > > > > Agree... but that's "just bugs" and I suspect we could get > >90% test > > > > > coverage for Linux systems just by checking util-linux (and > the kernel > > > > > itself). Maybe for extra style points also check on of the BSDs. > > > > > > > > It is worth stepping back from the details to take a look at > the intent. > > > The > > > > purpose of this entire section of EBBR is to describe how > firmware and > > > the > > > > OS can co-exist on the same media device. In broad strokes it > means if > > > > firmware is stored on the block device, then the OS must > constrain how it > > > > uses the device. > > > > > > > > On platforms with separate firmware storage (e.g., SPI flash > or UFS boot > > > > partitions) this isn't an issue. The OS can blow away > everything on the > > > disk > > > > and recreate it. > > > > > > > > But when it is an issue, the rules need to lay down what regions > > > (offsets, > > > > partitions, or file paths) firmware is allowed to own and what > the OS is > > > and > > > > is not allowed to do. e.g., the OS is allowed to erase and > recreate the > > > OS > > > > partitions, but it is not allowed to write a blank GPT or > erase the > > > system > > > > partition. > > > > > > > > I think the EBBR spec should focus on defining exactly what > restrictions > > > on > > > > the OS are, and how the restrictions are communicated. Then OS > vendors > > > have > > > > a fighting chance of supporting the restricted platforms well. > > > > > > > > Ultimately though this is a guide and the OS could choose to > ignore the > > > > restrictions... in which case it gets to keep the unbootable > brick when > > > it > > > > does. :-) > > > > > > Agree with all above. > > > > > > Also I think we can turn at least part of the original issue into a > > > concrete question. > > > > > > We have a SOC with some magic values hard coded into its boot > ROM. The > > > System Firmware author wants to ship it with the following GPT > on the > > > shared eMMC. > > > > > > LBA0 Protective MBR > > > LBA1 Primary GPT header > > > LBA2..18001 Reserved, mixture of dead space and a system firmware > > > loaded by Boot rom > > > LBA18002 Start of partition arrray (Entry 1, 2, 3, 4) > > > ... > > > LBA18033 End of partition arrray > > > LBA18034 Start of allocatable partition space > > > LBA-33..-1 End of disk is labelled as normal > > > > > > (or in a shorter GPT jargon form, a system where > PartitionEntryLBA is > > > 18002). > > > > > > Is such a system EBBR compliant? If yes, should it be? > > > > > > I would say it is not EBBR compliant because it does not follow > EFI spec > > and we mandate it in EBBR. > > Sure, if there is language in the EFI spec that prohibits this then the > answer is a no brainer. > > Assuming you've found such language could you quote your references? ;-) > > Oups! I thought of GPT Header being at 18002..... > as you push the firstUsableLBA... it seems to be valid in that EFI > compliant and hence EBBR compliant ;-) > > That said to get the GPT Partition move, the spec patch to table 20 is > not impressive: > image.png > - set to 0x000001 (ie... > + the LBA to the GPT partition header The position of the GPT *HEADER* in Daniel's example is LBA 1 and should not be changed to stay UEFI compliant. Daniel moved the first GPT *TABLE* whose position is defined in the GPT header and this is UEFI compliant. Best regards Heinrich > > > Daniel. > > > > Is the use case "valid"? I think it is valid because when you deal > with > > immutable BootROM you don't want complex code, GPT may evolve so > that you > > would have to evolve the BootROM... > > If we conclude this is a valid use case (and not creating ugly > legacy to > > deal with in the future), we need a clean reservation in EFI so > that GPT > > can start at an arbitrary LBA as 18002. > > enhancing the protective MBR semantics does not seem too complex to > > achieve. > > Can we list SoCs that have similar characteristic? > > > > > > > > Daniel. > > > > > > > > > PS 18002 is arbitrary but I think the example is sufficient in this > > > form and it was easier to diagram with a concrete number. > > > > > > > > > -- > > François-Frédéric Ozog | *Director Linaro Edge & Fog Computing Group* > > T: +33.67221.6485 > > francois.ozog(a)linaro.org <mailto:francois.ozog@linaro.org> | > Skype: ffozog > > > > -- > > François-Frédéric Ozog | /Director Linaro Edge & Fog Computing Group/ > T: +33.67221.6485 > francois.ozog(a)linaro.org <mailto:francois.ozog@linaro.org> | Skype: ffozog > >

6 years, 4 months

1
0
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[DTE] May 27th call agenda

by François Ozog

Hi, yet another email to spam you more.... I propose to have an Android DT overlay presentation next call and add topics that may arise from the list. Should you think we should discuss a particular topic, please respond to this mail thread. Cordially, Francois-Frederic

6 years, 4 months

4
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[DTE] May 27th agenda

by François Ozog

Hi, Please find below the May 27th agenda: - Project overall: FF (5 minutes) - EBBR spec / DT stuff advances (mail thread): Grant (10 minutes) - dynamic parts of device trees presentation: Heinrich (30 minutes) - DTviewer presentation and demo: CVS (15 minutes) Scratch pad notes and agenda can be found here: https://docs.google.com/document/d/1GfYYph_XKt1LHuCs1w9kjvyyYYw1R7AH3dlZwIX… -- FF PS: I bcc'ed different lists until we have everyone on the boot-architecture mailing list. Please make sure you are on this list. The work addressed in DT Evolution project spans many operating systems, boot firmwares, trust environments and processor architectures.

6 years, 4 months

2
2
0 0

[EBBR PATCH v3 1/2] Update spec to address UEFI 2.8 Errata A

by Grant Likely

UEFI 2.8 Errata A changed RuntimeServiceSupported value to be passed via an EFI_RT_PROPERTIES_TABLE instead of via a runtime variable. This is a breaking change and we should do a new EBBR release in short order to keep EBBR up to date with what is in UEFI. However, real world impact is minimal. U-Boot has already converted to the new method, and Linux only ever implemented the EFI_RT_PROPERTIES_TABLE method. Cc: Andrei Warkentin <awarkentin(a)vmware.com> Cc: Francois Ozog <francois.ozog(a)linaro.org> Cc: Ard Biesheuvel <ardb(a)kernel.org> Signed-off-by: Grant Likely <grant.likely(a)arm.com> --- source/chapter2-uefi.rst | 7 ++++--- source/references.rst | 6 +++--- 2 files changed, 7 insertions(+), 6 deletions(-) diff --git a/source/chapter2-uefi.rst b/source/chapter2-uefi.rst index 82b1a42..c42691b 100644 --- a/source/chapter2-uefi.rst +++ b/source/chapter2-uefi.rst @@ -9,7 +9,7 @@ platforms. UEFI Version ============ -This document uses version 2.8 of the UEFI specification [UEFI]_. +This document uses version 2.8 Errata A of the UEFI specification [UEFI]_. UEFI Compliance =============== @@ -111,7 +111,7 @@ during both boot services and runtime services. However, it isn't always practical for all EFI_RUNTIME_SERVICES functions to be callable during runtime services due to hardware limitations. If any EFI_RUNTIME_SERVICES functions are only available during boot services -then firmware shall provide the global `RuntimeServicesSupported` variable to +then firmware shall provide the `EFI_RT_PROPERTIES_TABLE` to indicate which functions are available during runtime services. Functions that are not available during runtime services shall return EFI_UNSUPPORTED. @@ -202,7 +202,8 @@ If a platform does not implement modifying non-volatile variables with SetVariable() after ExitBootServices(), then firmware shall return EFI_UNSUPPORTED for any call to SetVariable(), and must advertise that SetVariable() isn't available during runtime services -via the `RuntimeServicesSupported` variable as defined in [UEFI]_ § 8.1. +via the `RuntimeServicesSupported` value in the `EFI_RT_PROPERTIES_TABLE` +as defined in [UEFI]_ § 4.6. EFI applications can read `RuntimeServicesSupported` to determine if calls to SetVariable() need to be performed before calling ExitBootServices(). diff --git a/source/references.rst b/source/references.rst index d901bb1..1eb0509 100644 --- a/source/references.rst +++ b/source/references.rst @@ -20,6 +20,6 @@ <https://static.docs.arm.com/den0044/b/DEN0044B_Server_Base_Boot_Requirement…>`_ 8 March 2016, `Arm Limited <http://arm.com>`_ -.. [UEFI] `Unified Extensable Firmware Interface Specification v2.8 - <http://www.uefi.org/sites/default/files/resources/UEFI_Spec_2_8_final.pdf>`_, - March 2019, `UEFI Forum <http://www.uefi.org>`_ +.. [UEFI] `Unified Extensable Firmware Interface Specification v2.8 Errata A + <https://uefi.org/sites/default/files/resources/UEFI_Spec_2_8_A_Feb14.pdf>`_, + February 2020, `UEFI Forum <http://www.uefi.org>`_ -- 2.20.1

6 years, 4 months

1
2
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EBBR v1.0.1 release in the near future

by Grant Likely

Hi all, I'm considering doing a quick point-release for EBBR to address the change to RuntimeServicesSupported in UEFI 2.8 Errata A. From 2.8final to 2.8_A, RuntimeServicesSupported changed from being a variable to data in a system table entry. U-Boot and Linux have been updated to the UEFI method. EBBR needs to be changed to match. There are patches on this list under discussion now. Once that is complete and the patches merged, how does everyone feel about an EBBR v1.0.1 release before the end of May? At this moment, the v1.0.1 changes would include: e47952b (HEAD -> master, glikely/master) Specify details of how a DTB is passed to the OS c155e96 Update spec to address UEFI 2.8 Errata A 7fad894 (origin/master, origin/HEAD) Fix all UEFI references to be the same version 498cad2 trivial: Fix typo in chater 3 title 2c40029 Merge pull request #43 from orangecms/link-to-linux-doc 1e51a1e Update link to Linux docs which changed to rst be7ddfa Update CONTRIBUTING.rst 763aed0 Update CONTRIBUTING.rst All of the above can be found queued up at http://github.com/glikely/ebbr g. IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.

6 years, 4 months

5
11
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[DTE] DT update policies

by François Ozog

Hi, Following the presentation byt Joakim: https://docs.google.com/presentation/d/1CvKBBZ33ggzyhP2ub8iZ410I_KGrFjHftZL… The following does **NOT** represent consensus. I'd like to use those statements to trigger discussion: - a DTB (say osDTB) is passed from firmware to "downstream" OS; firmware can't use that DTB (read/write) after that event (Grant - separate active discussion thread in boot-architecture mailing list) - that osDTB is distinct from any DTBes that are used by firmware components. All may still be derived from a single repository (Joakim) - osDTB can be the result of applying programmatic fixups by diverse firmware components or by providing separate overlays to be merged later (last firmware component in the boot chain or by the OS itself), or by directly merging overlays (FF) - there are provisions in U-Boot to "sign" pieces of osDTB (Simon) - we need policies on what can be updated on osDTB, who can do it and how to verify them (Grant) - We don't want private keys in device so sign parts of osDTBs - there are no tools in Linux to deal with overlays (Heinrich), so for the moment we need firmware to aggregate any overlays into osDTB (FF) Cordially, Francois-Frederic

6 years, 4 months

1
0
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[DTE] May 1"th meeting notes and other meetings

by François Ozog

Hi, please find the meeting notes: https://docs.google.com/document/d/1bz3BfVlXvvHO-kKC0Y1N2SGqPjlxe5eu3dM8sKU… As a reminder: there will be two calls per month: - 2nd wednesday 2pm UTC - 4th wednesday 2pm UTC 2pm UTC currently corresponds to 7am PST / 4pm CET. Call to be added to your agendas if you did not received it by mail: Device Tree Evolution forum calls. - 2nd Wednesday of the month prime focus: system device tree and RTOS tools. - 4th Wednesday of the month prime focus: device tree life cycle, overlays, authentication and unified repository Those calls are public. Participants are advised they should not introduce topics that relate to confidential matters. https://zoom.us/j/97895025968?pwd=N0JWWFBqY0Npdi9RY2JIOFc1ZzI0UT09 join by phone: https://zoom.us/u/asu8Yfroy meeting ID: 978 9502 5968 Password: 270935 Cordially, François-Frédéric

6 years, 4 months

1
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[EBBR PATCH] Add EFI GUID for device tree blob

by Grant Likely

None of the relevent specs (EFI, DT, EBBR) specify the GUID for passing a DTB. Add it to the EBBR document so it is documented somewhere relevant. Fixes: #45 Cc: Andrei Warkentin <awarkentin(a)vmware.com> Cc: Francois Ozog <francois.ozog(a)linaro.org> Signed-off-by: Grant Likely <grant.likely(a)arm.com> --- source/chapter2-uefi.rst | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/source/chapter2-uefi.rst b/source/chapter2-uefi.rst index f6a5802..cf2f652 100644 --- a/source/chapter2-uefi.rst +++ b/source/chapter2-uefi.rst @@ -86,6 +86,16 @@ tables. - An Advanced Configuration and Power Interface [ACPI]_ table, or - a Devicetree [DTSPEC]_ system description +A Devicetree system description MUST be provided in Flattened Devicetree (DTB) +format version 17 or higher. +The following GUID must be used in the EFT system table to identify the DTB. + +.. code-block:: c + + #define EFI_DTB_GUID \ + EFI_GUID(0xb1b621d5, 0xf19c, 0x41a5, \ + 0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0) + As stated above, EBBR systems must not provide both ACPI and Devicetree tables at the same time. Systems that support both interfaces must provide a configuration -- 2.20.1 IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.

6 years, 4 months

7
42
0 0

DT Evolution forum calls

by François Ozog

Hi, As per the results of the poll (https://docs.google.com/spreadsheets/d/1WdsXgUoS3naL_-5eap1e_Sd9t0PM60s0Ljs…), there will be two calls per month: - 2nd wednesday 2pm UTC - 4th wednesday 2pm UTC 2pm UTC currently corresponds to 7am PST / 4pm CET. Call to be added to your agendas if you did not received it by mail: Device Tree Evolution forum calls. - 2nd Wednesday of the month prime focus: system device tree and RTOS tools. - 4th Wednesday of the month prime focus: device tree life cycle, overlays, authentication and unified repository Those calls are public. Participants are advised they should not introduce topics that relate to confidential matters. https://zoom.us/j/97895025968?pwd=N0JWWFBqY0Npdi9RY2JIOFc1ZzI0UT09 join by phone: https://zoom.us/u/asu8Yfroy meeting ID: 978 9502 5968 Password: 270935 Cordially, François-Frédéric Ozog, Linaro

6 years, 4 months

1
0
0 0

[PATCH v2 1/2] Update spec to address UEFI 2.8 Errata A

by Grant Likely

UEFI 2.8 Errata A changed RuntimeServiceSupported value to be passed via an EFI_RT_PROPERTIES_TABLE instead of via a runtime variable. This is a breaking change and we should do a new EBBR release in short order to keep EBBR up to date with what is in UEFI. However, real world impact is minimal. U-Boot has already converted to the new method, and Linux only ever implemented the EFI_RT_PROPERTIES_TABLE method. Cc: Andrei Warkentin <awarkentin(a)vmware.com> Cc: Francois Ozog <francois.ozog(a)linaro.org> Cc: Ard Biesheuvel <ardb(a)kernel.org> Signed-off-by: Grant Likely <grant.likely(a)arm.com> --- source/chapter2-uefi.rst | 7 ++++--- source/references.rst | 6 +++--- 2 files changed, 7 insertions(+), 6 deletions(-) diff --git a/source/chapter2-uefi.rst b/source/chapter2-uefi.rst index 82b1a42..c42691b 100644 --- a/source/chapter2-uefi.rst +++ b/source/chapter2-uefi.rst @@ -9,7 +9,7 @@ platforms. UEFI Version ============ -This document uses version 2.8 of the UEFI specification [UEFI]_. +This document uses version 2.8 Errata A of the UEFI specification [UEFI]_. UEFI Compliance =============== @@ -111,7 +111,7 @@ during both boot services and runtime services. However, it isn't always practical for all EFI_RUNTIME_SERVICES functions to be callable during runtime services due to hardware limitations. If any EFI_RUNTIME_SERVICES functions are only available during boot services -then firmware shall provide the global `RuntimeServicesSupported` variable to +then firmware shall provide the `EFI_RT_PROPERTIES_TABLE` to indicate which functions are available during runtime services. Functions that are not available during runtime services shall return EFI_UNSUPPORTED. @@ -202,7 +202,8 @@ If a platform does not implement modifying non-volatile variables with SetVariable() after ExitBootServices(), then firmware shall return EFI_UNSUPPORTED for any call to SetVariable(), and must advertise that SetVariable() isn't available during runtime services -via the `RuntimeServicesSupported` variable as defined in [UEFI]_ § 8.1. +via the `RuntimeServicesSupported` value in the `EFI_RT_PROPERTIES_TABLE` +as defined in [UEFI]_ § 4.6. EFI applications can read `RuntimeServicesSupported` to determine if calls to SetVariable() need to be performed before calling ExitBootServices(). diff --git a/source/references.rst b/source/references.rst index d901bb1..1eb0509 100644 --- a/source/references.rst +++ b/source/references.rst @@ -20,6 +20,6 @@ <https://static.docs.arm.com/den0044/b/DEN0044B_Server_Base_Boot_Requirement…>`_ 8 March 2016, `Arm Limited <http://arm.com>`_ -.. [UEFI] `Unified Extensable Firmware Interface Specification v2.8 - <http://www.uefi.org/sites/default/files/resources/UEFI_Spec_2_8_final.pdf>`_, - March 2019, `UEFI Forum <http://www.uefi.org>`_ +.. [UEFI] `Unified Extensable Firmware Interface Specification v2.8 Errata A + <https://uefi.org/sites/default/files/resources/UEFI_Spec_2_8_A_Feb14.pdf>`_, + February 2020, `UEFI Forum <http://www.uefi.org>`_ -- 2.20.1

6 years, 4 months

1
1
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[PATCH] Update spec to address UEFI 2.8 Errata A

by Grant Likely

UEFI 2.8 Errata A changed RuntimeServiceSupported value to be passed via an EFI_RT_PROPERTIES_TABLE instead of via a runtime variable. This is a breaking change and we should do a new EBBR release in short order to keep EBBR up to date with what is in UEFI. Unsure what the overall impact will be. U-Boot implements the variable method which will need to be changed to a table. It is unclear if any OSes depend heavily on it being implemented. Cc: Andrei Warkentin <awarkentin(a)vmware.com> Cc: Francois Ozog <francois.ozog(a)linaro.org> Cc: Ard Biesheuvel <ardb(a)kernel.org> Signed-off-by: Grant Likely <grant.likely(a)arm.com> --- source/chapter2-uefi.rst | 7 ++++--- source/references.rst | 6 +++--- 2 files changed, 7 insertions(+), 6 deletions(-) diff --git a/source/chapter2-uefi.rst b/source/chapter2-uefi.rst index fe03ae3..b622abe 100644 --- a/source/chapter2-uefi.rst +++ b/source/chapter2-uefi.rst @@ -9,7 +9,7 @@ platforms. UEFI Version ============ -This document uses version 2.8 of the UEFI specification [UEFI]_. +This document uses version 2.8 Errata A of the UEFI specification [UEFI]_. UEFI Compliance =============== @@ -111,7 +111,7 @@ during both boot services and runtime services. However, it isn't always practical for all EFI_RUNTIME_SERVICES functions to be callable during runtime services due to hardware limitations. If any EFI_RUNTIME_SERVICES functions are only available during boot services -then firmware shall provide the global `RuntimeServicesSupported` variable to +then firmware shall provide the `EFI_RT_PROPERTIES_TABLE` to indicate which functions are available during runtime services. Functions that are not available during runtime services shall return EFI_UNSUPPORTED. @@ -202,7 +202,8 @@ If a platform does not implement modifying non-volatile variables with SetVariable() after ExitBootServices(), then firmware shall return EFI_UNSUPPORTED for any call to SetVariable(), and must advertise that SetVariable() isn't available during runtime services -via the `RuntimeServicesSupported` variable as defined in [UEFI]_ § 8.1. +via the `RuntimeServicesSupported` value in the `EFI_RT_PROPERTIES_TABLE` +as defined in [UEFI]_ § 4.6. EFI applications can read `RuntimeServicesSupported` to determine if calls to SetVariable() need to be performed before calling ExitBootServices(). diff --git a/source/references.rst b/source/references.rst index d901bb1..1eb0509 100644 --- a/source/references.rst +++ b/source/references.rst @@ -20,6 +20,6 @@ <https://static.docs.arm.com/den0044/b/DEN0044B_Server_Base_Boot_Requirement…>`_ 8 March 2016, `Arm Limited <http://arm.com>`_ -.. [UEFI] `Unified Extensable Firmware Interface Specification v2.8 - <http://www.uefi.org/sites/default/files/resources/UEFI_Spec_2_8_final.pdf>`_, - March 2019, `UEFI Forum <http://www.uefi.org>`_ +.. [UEFI] `Unified Extensable Firmware Interface Specification v2.8 Errata A + <https://uefi.org/sites/default/files/resources/UEFI_Spec_2_8_A_Feb14.pdf>`_, + February 2020, `UEFI Forum <http://www.uefi.org>`_ -- 2.20.1

6 years, 5 months

2
2
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[PATCH] trivial: Fix typo in chater 3 title

by Grant Likely

Fixes: #42 Signed-off-by: Grant Likely <grant.likely(a)arm.com> --- source/chapter3-secureworld.rst | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff --git a/source/chapter3-secureworld.rst b/source/chapter3-secureworld.rst index 4e9fa61..9c51bca 100644 --- a/source/chapter3-secureworld.rst +++ b/source/chapter3-secureworld.rst @@ -1,8 +1,8 @@ .. SPDX-License-Identifier: CC-BY-SA-4.0 -****************************** -Priviledged or Secure Firmware -****************************** +***************************** +Privileged or Secure Firmware +***************************** AArch32 Multiprocessor Startup Protocol ======================================= -- 2.20.1

6 years, 5 months

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DTE call meeting notes

by François Ozog

Hi, Thank you for your participation in yesterday's call. Here are meeting notes that you can update <https://docs.google.com/document/d/13TwImAK9bta5_qY2PAFplO6pypd0hpNQNkpkI_W…>as you see fit (I think the permissions associated with this new link are correct). Survey was answered by 12 participants while there were 27 people on the call. I would be more comfortable to select a time with more responses. Cordially, François-Frédéric -- François-Frédéric Ozog | Director Linaro Edge & Fog Computing Group T: +33.67221.6485 francois.ozog(a)linaro.org | Skype: ffozog

6 years, 5 months

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DTE discussion agenda

by François Ozog

Hi, Here is the agenda for today's call <http://meet.google.com/oua-wrbf-ppi>: - DTE activities for the next cycle and overall organization - Regular meeting setup (survey <https://www.surveymonkey.com/r/F72TLPF>) - System Device Tree status and roadmap (JIRA?) this topic depends on presence of SDT stakeholders - Device Tree specification: its role in the future and short term - Device Tree lifecycle (what happens to a DT from TFA to OS): a presentation and a discussion Cheers FF

6 years, 5 months

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DTE weekly

by François Ozog

Hi, I am taking over Steve to drive Device Tree Evolution project except the System Device Tree which will continue to evolve under the leadership of Nathalie and Stefano. To discuss: - lifecycle (how TFA, OP-TEE, U-Boot and Operating Systems deal with DT and pass information between them) - overlays - unified repo - summary of System DT activities I'd like to set up a weekly call starting next week. Please state the best timeslot in this poll: https://www.doodle.com/poll/k57zhwa4q9caivgy (the poll proposes the timeslot to be repeated). By next week, Joakim, Ilias and myself will have prepared some content to launch/continue debate. Cordially, François-Frédéric -- François-Frédéric Ozog | *Director Linaro Edge & Fog Computing Group* T: +33.67221.6485 francois.ozog(a)linaro.org | Skype: ffozog

6 years, 5 months

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Invitation: DTE discussion @ Mon 4 May 2020 18:00 - 19:00 (CEST) (boot-architecture@lists.linaro.org)

by François Ozog

You have been invited to the following event. Title: DTE discussion This is a one off meeting unless we find a sustainable timeslot for India participants. When: Mon 4 May 2020 18:00 – 19:00 Central European Time - Paris Joining info: Join with Google Meet https://meet.google.com/oua-wrbf-ppi Join by phone +33 1 87 40 48 87 (PIN: 588964477) More phone numbers: https://tel.meet/oua-wrbf-ppi?pin=4737911870439&hs=0 Calendar: boot-architecture(a)lists.linaro.org Who: * François Ozog- organiser * boot-architecture(a)lists.linaro.org * team-ledge * dte-all Event details: https://www.google.com/calendar/event?action=VIEW&eid=NzRkanQyMXZtOWwzc2xic… Invitation from Google Calendar: https://www.google.com/calendar/ You are receiving this courtesy email at the account boot-architecture(a)lists.linaro.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

6 years, 5 months

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Re: DTE-8 DeviceTree lifecycle: the basics

by François Ozog

+boot architecture Le sam. 25 avr. 2020 à 19:26, François Ozog <francois.ozog(a)linaro.org> a écrit : > Hi > > I would like to start the discussion on DTE-8 as LEDGE is going to need > results soon. I'd like to keep it high level, general principles, not too > precise on implementation details. Let's take overlays and other > complications out of the discussion until we share a vision for the basics. > > When we have concluded this discussion cycle we will need to address: > - DTE-8 DeviceTree lifecycle: BL32 (BL32 may mask some devices until > given credentials...) > - DTE-8 DeviceTree lifecycle: overlays > - DTE-8 DeviceTree lifecycle: tooling > - DTE-8 DeviceTree lifecycle: chain of trust > > Is the following correct? > Is it complete on the target reduced scope? > Is the discussion series/roadmap complete, is the order right ? > > Cordially, > > François-Frédéric > > > I - Definitions > > Let's consider there are four trees used by the following entities: > - TFA which spans BL1, BL2, BL31 has a tree <TFA> which originates from > tfa.dtb > - BL32 (let's assume OP-TEE) has a tree <BL32> which originates from > bl32.dtb > - BL33 (let's assume U-Boot) has a tree <BL33> which originates from > bl33.dtb > - THING, the "thing" that is booted by BL33, has a tree <THING> which > originates from thing.dtb and manipulations from BL33. > > The THING can be a Linux kernel, a bsd kernel, grub, shim<arch>.efi, > efibootguard.efi, Xen, Hafnium or many other possibilities. > BL33 is assumed to be U-Boot but it can be EDK2, Linux Kernel, Hafnium, > Xen or other thing. > > A tree is not dtb. A tree is the result of loading a DTB with or without > manipulations. > > II - Build time assumptions > > It is assumed that TFA, BL32 and BL33 are board specific while THINGS is > board agnostic. > > As a result of this architectural decision: > - tfa.dtb, bl32.dtb and bl33.dtb can be built by the build process of the > respective entity TFA, BL32, BL33. > - thing.dtb is purely describing hardware and has no "chosen" nodes for > instance, it may contain architectural/platform/board specific > "reserved-memory". In other words, nothing that can tie it to a particular > "thing". > > All DTBs shall be derived from a single source repository. > > The bindings of a single piece of hardware, may differ depending on the > entity that needs it (there are many ways to implement that aspect, let's > not talk about implementation yet). > For instance, a display panel for BL33 can be represented as a single > small node while the same display panel can be controlled out of several > large nodes by a downstream Operating System. > > III - Lifecycle > > Out of all possible transitions, let's consider BL31->BL33 and > BL33->THING. Transitions are opportunities to pass DT information from one > entity to the other that complements the static *.dtb . For instance, > passing PSCI interface information, memory reservations, PCI IO ranges... > > III.1 BL31->BL33 > > III.1.1 nature of manipulations > typically, PSCI interface may be injected as well some memory > reservations. > > III.1.2 manipulation operational considerations > There are three possibilities for passing this information: > - BL31 manipulates the BL33 tree to add/change nodes > - BL33 asks BL31 to add/change nodes > - BL31 passes an interim tree that BL33 will merge into his. > > Current wisdom is BL31 manipulates the BL33 tree. > > III.2 BL33->THING > > III.2.1 nature of manipulations > * operational > - board information (part numbers, serial numbers...) > - memory layout (beyond the typical 4G) > - IO specifics (PCIe...) > - reserved areas for runtime services (UEFI for instance) > - os.dtb > * THING dependent elements > - chosen for "command line" or other aspects > > III.2.2 manipulation operational considerations > In the case of UEFI interface, os.dtb passed as DT artifact or a UEFI > table shall be referring to the same tree (a single tree in memory, two > access methods). > > BL33 will operate all necessary manipulations on os.dtb before passing it > to the THING. The THING (grub, efiapp, kernel) can further operate > manipulations, it is outside scope of the discussion. > > > > -- > François-Frédéric Ozog | *Director Linaro Edge & Fog Computing Group* > T: +33.67221.6485 > francois.ozog(a)linaro.org | Skype: ffozog > > -- François-Frédéric Ozog | *Director Linaro Edge & Fog Computing Group* T: +33.67221.6485 francois.ozog(a)linaro.org | Skype: ffozog

6 years, 5 months

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[RFC] Systemd-boot and EBBR

by François Ozog

Hi, I instrumented boot on my Ubuntu 18.04 server right after systemd startup and caught an access to: /sys/firmware/efi/efivars/LoaderDevicePartUUID-4a67b082-0a4c-41cf-b6c7-440b29bb8c4f This led to: https://systemd.io/DISCOVERABLE_PARTITIONS/ And then: https://systemd.io/BOOT_LOADER_INTERFACE/ https://systemd.io/AUTOMATIC_BOOT_ASSESSMENT/ My server is configured with Grub to boot (grub and kernel on a HD, root FS of NVME as grub do not have nvme driver for my card) but the udev is still checking those systemd-boot variables. >From a boot loader perspective, we have the following EFI applications: - Grub2 - EFIBootGuard (used by CIP) - Systemd-boot (used by ?) Regardless of the loader, I assume we need to ensure whatever option is selected by solution builders, they can implement it with our U-Boot reference implementation of UEFI. The Systemd boot-bless seems of high interest for rolling back UEFI update capsules of firmware... I'd be happy to get some feed back on : - the systemd-boot technology - whether we need to implement the above specs in our UEFI implementation - whether this has an influence on EBBR Cheers FF PS: other references https://manpages.debian.org/testing/systemd/systemd-boot.7.en.html https://manpages.debian.org/testing/systemd/systemd-bless-boot.service.8.en… http://man7.org/linux/man-pages/man1/bootctl.1.html -- François-Frédéric Ozog | *Director Linaro Edge & Fog Computing Group* T: +33.67221.6485 francois.ozog(a)linaro.org | Skype: ffozog

6 years, 5 months

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Re: RFC: EBBR specification update

by Heinrich Schuchardt

On 3/11/20 3:20 PM, Francois Ozog wrote: > > > On Wed, 11 Mar 2020 at 13:42, Francois Ozog <francois.ozog(a)linaro.org > <mailto:francois.ozog@linaro.org>> wrote: > > > > On Wed, 11 Mar 2020 at 12:45, Daniel Thompson > <daniel.thompson(a)linaro.org <mailto:daniel.thompson@linaro.org>> wrote: > > On Wed, Mar 11, 2020 at 11:20:17AM +0100, Francois Ozog wrote: > > On Wed, 11 Mar 2020 at 07:48, Heinrich Schuchardt > <xypron.glpk(a)gmx.de <mailto:xypron.glpk@gmx.de>> wrote: > > > On 3/11/20 12:04 AM, Heinrich Schuchardt wrote: > > > > On 3/10/20 7:37 PM, Francois Ozog wrote: > > > >> Le mar. 10 mars 2020 à 18:37, Daniel Thompson > > > >> <daniel.thompson(a)linaro.org > <mailto:daniel.thompson@linaro.org>> a écrit : > > > >>> On Tue, Mar 10, 2020 at 05:35:40PM +0100, Francois Ozog > wrote: > > > >>>> This is driven by the BL2 which is platform specific > and I am not sure > > > >>>> we can have any influence. > > > >>>> The flashimage.bin in a number of system consists of a > (blob) FIP that > > > >>>> has BL2, SCP stuff, BL31, BL32, BL33. > > > >>>> Ilias upstream U-Boot patches to change from "ADR" to > "ADRL" because > > > >>>> the code grew too much. > > > >>> > > > >>> I'm not quite sure I understand the concern here. > > > >>> > > > >>> Are you still working on systems where the boot ROM > mandates using MBR > > > >>> partitioning and attempting to put secure boot on it? > If so perhaps we > > > >>> could simply discontinue MBR support for systems with > secure boot! > > > >>> > > > >> > > > >> Well..... we want Products on the market to benefit from > EBBR compliance > > > >> rather than two years from now. So MBR is inevitable. > And is not that a > > > >> pain ;-) Of course its not as clean as we would like but > “sales first”! > > > > > > > > A typical problem is that a SoC has an entry address > within the first 17 > > > > KiB, e.g. the Allwinner CPUs want a firmware entry point > at 0x2000. If I > > > > correctly understand the UEFI standard, one might use > PartitionEntryLBA > > > > to place the GPT Partition Entry Array behind the > firmware in this case. > > > > > > > > > > In the expert mode of gdisk there is command 'j' for moving > the GPT > > > Partition Entry Array to an arbitrary sector. This will > protect the area > > > between the GPT header and the GPT Partition Entry Array > from being used > > > for a partition. The same can be done with parameter -j of > sgdisk. > > > > > > Furthermore gdisk supports creating a hybrid MBR. This > allow to have > > > GUID partition table and a MBR partion table at the same > time where the > > > MBR partition table mirrors up to three GPT partitions and > the fourth > > > MBR partition is used to protect the GUID partition table. > > > > > > So requiring GPT and having boards only supporting booting > from an MBR > > > partition (like the Raspberry) seems not to be exclusive. > > > > > > > That sounds like a great solution! > > The last time we discussed this there was *very* strong opposition > during meetings to hybrid partitioning and IIRC language was > added to > the spec to prohibit it. > > Hybrid partitioning is a problem because it imposes to difficult > to meet > constraints on partitioning tools provided by the operating system. > > In other words if we permit hybrid partitioning in order that > boot code > can find the firmware then the operating system would inherit a > duty to > not to screw up the firmware loading when it modifies the partition > tables. It is hard to express how the OS should go about that. > > Hence the current approach where we accept that MBR partitioning > offers an inferior feature set to GPT. > > > We have the following cases: > > - FW compatible with GPT (I mean firmware can be searched based on > GUID partition) > Ok > > - FW that uses offsets and can be positioned at LBA >= 33 > Ok > Need to define a protective partition > > - FW that uses offsets and can be positioned such that space between > LBA-2 and LBA-33 is used. > Ok in theory as the header states where the partition entries > location is specified in a GPT_HEADER "Starting LBA of array of > partition entries". > Linux kernel properly loads the partition entries if we push them > after 16MB. > > read_lba <https://elixir.bootlin.com/linux/latest/ident/read_lba>(state, le64_to_cpu > <https://elixir.bootlin.com/linux/latest/ident/le64_to_cpu>(gpt->partition_entry_lba) > > But I bet 2 is hardcoded in many tools... > > If I had done my homework properly, I would have seen that > U-Boot CONFIG_EFI_PARTITION_ENTRIES_OFF is just configuring that... CONFIG_EFI_PARTITION_ENTRIES_OFF is only relevant if you use U-Boot to create a GUID partition table. When reading a GPT U-Boot correctly considers the current value of PartitionEntryLBA. Best regards Heinrich > So there is some experience in playing with that.... I'd be happy to > read ;-) > > - FW that supposes LBA-1 (macchiatobin the firmware blob that > contain TF-A must be here) > > In theory OK as Linux will detect bad signature and use the > alternate GPT > > good_pgpt = is_gpt_valid > <https://elixir.bootlin.com/linux/latest/ident/is_gpt_valid>(state, GPT_PRIMARY_PARTITION_TABLE_LBA > <https://elixir.bootlin.com/linux/latest/ident/GPT_PRIMARY_PARTITION_TABLE_L…>, > &pgpt, &pptes); > if (good_pgpt) > good_agpt = is_gpt_valid > <https://elixir.bootlin.com/linux/latest/ident/is_gpt_valid>(state, > le64_to_cpu > <https://elixir.bootlin.com/linux/latest/ident/le64_to_cpu>(pgpt->alternate_lba), > &agpt, &aptes); > if (!good_agpt && force_gpt <https://elixir.bootlin.com/linux/latest/ident/force_gpt>) > good_agpt = is_gpt_valid > <https://elixir.bootlin.com/linux/latest/ident/is_gpt_valid>(state, lastlba, &agpt, &aptes); > > We loose the protective nature of GPT but it sounds like it will be > working. > > That said, we could enhance the EFI specification so that: > - we have a firmware protective partition > - the start LBA of the "GPT protective partition (0xEE)" is used to > define the GPT header placement instead of 1. > image.png > > Daniel. > > > > -- > > François-Frédéric Ozog | /Director Linaro Edge & Fog Computing Group/ > T: +33.67221.6485 > francois.ozog(a)linaro.org <mailto:francois.ozog@linaro.org> > | Skype: ffozog > > > > > -- > > François-Frédéric Ozog | /Director Linaro Edge & Fog Computing Group/ > T: +33.67221.6485 > francois.ozog(a)linaro.org <mailto:francois.ozog@linaro.org> | Skype: ffozog > >

6 years, 6 months

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Re: RFC: EBBR specification update

by Francois Ozog

Le mar. 10 mars 2020 à 18:46, Mark Brown <broonie(a)kernel.org> a écrit : > On Tue, Mar 10, 2020 at 05:37:29PM +0000, Daniel Thompson wrote: > > On Tue, Mar 10, 2020 at 05:35:40PM +0100, Francois Ozog wrote: > > > > Thanks Leif for the links. I tend to like the ETSI one because it is > > > somewhat complete on necessary english grammar stuff. > > > But I am flexible, important we state explicitly the reference > > > document and we use the language constructs. > > > Does ETSI offer us "features" that are missing from RFC 2119. > > > Personally I would favour RFC 2119 simply because it is so much better > > known than the ETSI drafting rules. > > > If you cite RFC 2119 and I don't have to go and read anything... and > > even if I did it is super concise and quick to read. > > > Cite ETSI drafting rules, clause 3 and I have to put in a lot more > > effort. > > The RFC 2119 usage of "MUST" is also a more standard English usage (in > that people are more likely to be familiar with it) than the ETSI SHALL > so there's a bit of a comprehensibility win. RFC2119 sold on my side ;-) > > -- François-Frédéric Ozog | *Director Linaro Edge & Fog Computing Group* T: +33.67221.6485 francois.ozog(a)linaro.org | Skype: ffozog

6 years, 6 months

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FYI: Intel Vulnerability Serious But Unlikely, Experts Say

by Francois Ozog

Well, if you think IIot and Edge, you have physical access and the system is thus vulnerable.... https://www.sdxcentral.com/articles/news/intel-vulnerability-serious-but-un… Cheers FF PS: Intel CSME is an auxiliary micro-controller much like the SCP but with the capability to access the whole DRAM and having some TrustZone style role. -- François-Frédéric Ozog | *Director Linaro Edge & Fog Computing Group* T: +33.67221.6485 francois.ozog(a)linaro.org | Skype: ffozog

6 years, 6 months

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Dynamic acpi

by Francois Ozog

just in case: [PATCH 000/108] RFC: dm: Add programatic generation of ACP https://lists.denx.de/pipermail/u-boot/2020-January/397886.html May be some ideas fir DT overlays... FF -- François-Frédéric Ozog | *Director Linaro Edge & Fog Computing Group* T: +33.67221.6485 francois.ozog(a)linaro.org | Skype: ffozog

6 years, 8 months

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Sense of soc bus? (was: [PATCH] base: soc: Export soc_device_to_device() helper)

by Andreas Färber

Am 12.11.19 um 08:29 schrieb Uwe Kleine-König: > On Tue, Nov 12, 2019 at 06:23:47AM +0100, Greg Kroah-Hartman wrote: >> On Mon, Nov 11, 2019 at 09:10:41PM +0100, Andreas Färber wrote: >>> Am 11.11.19 um 07:40 schrieb Greg Kroah-Hartman: >>>> On Mon, Nov 11, 2019 at 06:42:05AM +0100, Andreas Färber wrote: >>>>> Am 11.11.19 um 06:27 schrieb Greg Kroah-Hartman: >>>>>> On Mon, Nov 11, 2019 at 05:56:09AM +0100, Andreas Färber wrote: >>>>>>> Use of soc_device_to_device() in driver modules causes a build failure. >>>>>>> Given that the helper is nicely documented in include/linux/sys_soc.h, >>>>>>> let's export it as GPL symbol. >>>>>> >>>>>> I thought we were fixing the soc drivers to not need this. What >>>>>> happened to that effort? I thought I had patches in my tree (or >>>>>> someone's tree) that did some of this work already, such that this >>>>>> symbol isn't needed anymore. >>>>> >>>>> I do still see this function used in next-20191108 in drivers/soc/. >>>>> >>>>> I'll be happy to adjust my RFC driver if someone points me to how! >>>> >>>> Look at c31e73121f4c ("base: soc: Handle custom soc information sysfs >>>> entries") for how you can just use the default attributes for the soc to >>>> create the needed sysfs files, instead of having to do it "by hand" >>>> which is racy and incorrect. >>> >>> Unrelated. >>> >>>>> Given the current struct layout, a type cast might work (but ugly). >>>>> Or if we stay with my current RFC driver design, we could use the >>>>> platform_device instead of the soc_device (which would clutter the >>>>> screen more than "soc soc0:") or resort to pr_info() w/o device. >>>> >>>> Ick, no, don't cast blindly. What do you need the pointer for? Is this >>>> for in-tree code? >>> >>> No, an RFC patchset: https://patchwork.kernel.org/cover/11224261/ >>> >>> As I indicated above, I used it for a dev_info(), which I can easily >>> avoid by using pr_info() instead: >>> >>> diff --git a/drivers/soc/realtek/chip.c b/drivers/soc/realtek/chip.c >>> index e5078c6731fd..f9380e831659 100644 >>> --- a/drivers/soc/realtek/chip.c >>> +++ b/drivers/soc/realtek/chip.c >>> @@ -178,8 +178,7 @@ static int rtd_soc_probe(struct platform_device *pdev) >>> >>> platform_set_drvdata(pdev, soc_dev); >>> >>> - dev_info(soc_device_to_device(soc_dev), >>> - "%s %s (0x%08x) rev %s (0x%08x) detected\n", >>> + pr_info("%s %s (0x%08x) rev %s (0x%08x) detected\n", >>> soc_dev_attr->family, soc_dev_attr->soc_id, chip_id, >>> soc_dev_attr->revision, chip_rev); >> >> First off, the driver should not be spitting out noise for when all goes >> well like this :) > > I didn't follow the discussion closely, but I think I want to object > here a bit. While I agree that each driver emitting some stuff to the > log buffer is hardly helpful, seeing the exact SoC details is indeed > useful at times. With my Debian kernel team member hat on, I'd say > keep this information. This way the SoC details make it into kernel bug > reports without effort on our side. Seconded. For example, RTD1295 will support LSADC only from revision B00 on (and it's not the first time I'm seeing such things in the industry). So if a user complains, it will be helpful to see that information. Referencing your Amlogic review, with all due respect for its authors, the common framework here just lets that information evaporate into the deeps of sysfs. People who know can check /sys/bus/soc/devices/soc0, but ordinary users will at most upload dmesg output to a Bugzilla ticket. And it was precisely info-level boot output from the Amlogic GX driver that made me aware of this common framework and inspired me to later contribute such a driver elsewhere myself. That's not a bad effect. ;) So if anything, we should standardize that output and move it into soc_device_register(): "<family> <soc_id> [rev <revision>] detected" with suitable NULL checks? (what I did above for Realtek, minus hex) The info level seems correct to me - it allows people to use a different log_level if they only care about warnings or errors on the console; it's not debug info for that driver, except in my case the accompanying hex numbers that I'd be happy to drop in favor of standardization. Another aspect here is that the overall amount of soc_device_register() users is just an estimated one third above the analysis shared before. In particular server platforms, be it arm64 or x86_64, that potentially have more than one SoC integrated in a multi-socket configuration, don't feed into this soc bus at all! Therefore my comment that dev_info()-printed "soc soc0:" is kind of useless if there's only one SoC on those boards. I'm not aware of any tool or a more common file aggregating this information, certainly not /proc/cpuinfo and I'm not aware of any special "lssoc" tool either. And if there's no ACPI/DMI driver feeding support-relevant information into this framework to be generally useful, I don't expect the big distros to spend time on improving its usability. So if we move info output into base/soc.c, we could continue using dev_info() with "soc"-grep'able prefix in the hopes that someday we'll have more than one soc device on the bus and will need to distinguish; otherwise yes, pr_info() would change the output format for Amlogic (and so would a harmonization of the text), but does anyone really care in practice? Tools shouldn't be relying on its output format, and humans will understand equally either way. Finally, arch/arm seems unique in that it has the machine_desc mechanism that allows individual SoCs to force creating their soc_device early and using it as parent for further DT-created platform_devices. With arm64 we've lost that ability, and nios2 is not using it either. A bad side effect (with SUSE hat on) is that this parent design pattern does not allow to build such drivers as modules, which means that distro configs using arm's multi-platform, e.g., CONFIG_ARCH_MULTI_V7 will get unnecessary code creep as new platforms get added over time (beyond the basic clk, pinctrl, tty and maybe timer). Even if it were possible to call into a driver module that early, using it as parent would seem to imply that all the references by its children would not allow to unload the module, which I'd consider a flawed design for such an "optional" read-once driver. If we want the device hierarchy to have a soc root then most DT based platforms will have a /soc DT node anyway (although no device_type = "soc") that we probably could have a device registered for in common code rather than each SoC platform handling that differently? That might then make soc_register_device() not the creator of the device (if pre-existent) but the supplier of data to that core device, which should then allow to unload the data provider with just the sysfs data disappearing until re-inserted (speeding up the develop-and-test cycle on say not-so-resource-constrained platforms). On the other hand, one might argue that such information should just be parsed by EBBR-conformant bootloaders and be passed to the kernel via standard UEFI interfaces and DMI tables. But I'm not aware of Barebox having implemented any of that yet, and even for U-Boot (e.g., Realtek based consumer devices...) not everyone has the GPL sources or tools to update their bootloader. So, having the kernel we control gather information relevant to kernel developers does make some sense to me. Thoughts? Regards, Andreas P.S. Sorry that a seemingly trivial one-line 0-day fix derailed into this fundamental use case discussion. arch/arm/mach-ep93xx/core.c: soc_dev = soc_device_register(soc_dev_attr); arch/arm/mach-imx/cpu.c: soc_dev = soc_device_register(soc_dev_attr); arch/arm/mach-mvebu/mvebu-soc-id.c: soc_dev = soc_device_register(soc_dev_attr); arch/arm/mach-mxs/mach-mxs.c: soc_dev = soc_device_register(soc_dev_attr); arch/arm/mach-omap2/id.c: soc_dev = soc_device_register(soc_dev_attr); arch/arm/mach-tegra/tegra.c: struct device *parent = tegra_soc_device_register(); arch/arm/mach-zynq/common.c: soc_dev = soc_device_register(soc_dev_attr); arch/nios2/platform/platform.c: soc_dev = soc_device_register(soc_dev_attr); drivers/soc/amlogic/meson-gx-socinfo.c: soc_dev = soc_device_register(soc_dev_attr); drivers/soc/amlogic/meson-mx-socinfo.c: soc_dev = soc_device_register(soc_dev_attr); drivers/soc/atmel/soc.c: soc_dev = soc_device_register(soc_dev_attr); drivers/soc/bcm/brcmstb/common.c: soc_dev = soc_device_register(soc_dev_attr); drivers/soc/fsl/guts.c: soc_dev = soc_device_register(&soc_dev_attr); drivers/soc/imx/soc-imx-scu.c: soc_dev = soc_device_register(soc_dev_attr); drivers/soc/imx/soc-imx8.c: soc_dev = soc_device_register(soc_dev_attr); drivers/soc/qcom/socinfo.c: qs->soc_dev = soc_device_register(&qs->attr); drivers/soc/realtek/chip.c: soc_dev = soc_device_register(soc_dev_attr); drivers/soc/renesas/renesas-soc.c: soc_dev = soc_device_register(soc_dev_attr); drivers/soc/samsung/exynos-chipid.c: soc_dev = soc_device_register(soc_dev_attr); drivers/soc/tegra/fuse/fuse-tegra.c: dev = soc_device_register(attr); drivers/soc/ux500/ux500-soc-id.c: soc_dev = soc_device_register(soc_dev_attr); drivers/soc/versatile/soc-integrator.c: soc_dev = soc_device_register(soc_dev_attr); drivers/soc/versatile/soc-realview.c: soc_dev = soc_device_register(soc_dev_attr); -- SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany GF: Felix Imendörffer HRB 36809 (AG Nürnberg)

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