Re: Public review of Supervisor Binary Interface (SBI) Specification


On Tue, Jan 18, 2022 at 2:46 PM Andrew Waterman <andrew@...> wrote:

On Wed, Jan 12, 2022 at 12:50 PM Jonathan Behrens <behrensj@...> wrote:
If that is the intention, the text should be changed to "Returns 0 if the given SBI extension ID (EID) is not available, or an implementation defined non-zero value if it is available". Although, if the extensions aren't defining any meaning to the various possible non-zero values, I personally don't see why we shouldn't change it to "returns one if it is available".

I think allowing implementation-defined nonzero rather than requiring it be 1 is OK, but I agree with your proposed wording change.

Sounds good to me as well. I will make the change.


On Wed, Jan 12, 2022 at 3:32 PM Atish Kumar Patra <atishp@...> wrote:
On Wed, Jan 12, 2022 at 10:59 AM Jonathan Behrens <behrensj@...> wrote:
> If I understand correctly, per the description of `sbi_probe_extension`, each of the extensions are supposed to specify an "extension-specific non-zero value" to return if they are available. However, right now I don't think any of them do. Is this something that should be fixed?

The description says "Returns 0 if the given SBI extension ID (EID) is
not available, or an extension-specific non-zero value if it is
The specification says it should be non-zero as the value "0"
indicates non-availability of the extension. The exact return value
should be an implementation detail.

> Jonathan
> On Wed, Jan 12, 2022 at 1:44 PM atishp via <> wrote:
>> I just realized that the below email was not delivered to unix
>> platform mailing list and
>> linux-riscv mailing list because of the attachment. Reseeding it again
>> without the
>> attachment. Apologies for the noise.
>> -----------------------------------------------------------------------------------------------
>> We are delighted to announce the start of the public review period for
>> the Non-ISA Supervisor Binary Interface (SBI) specification. The
>> SBI specification is considered as frozen now as per the RISC-V International
>> policies.
>> The review period begins today, Monday Jan 10, and ends on Monday
>> Jan 24 (inclusive).
>> The specification can be found here
>> which was generated from the source available in the following GitHub
>> repository:
>> To respond to the public review, please either reply to this email or
>> send comments to the platform mailing list[1] or add issues to the
>> SBI GitHub repo[2]. We welcome all input and appreciate your time and
>> effort in helping us by reviewing the specification.
>> During the public review period, corrections, comments, and
>> suggestions, will be gathered for review by the Platform HSC members. Any
>> minor corrections and/or uncontroversial changes will be incorporated
>> into the specification. Any remaining issues or proposed changes will
>> be addressed in the public review summary report. If there are no
>> issues that require incompatible changes to the public review
>> specification, the platform HSC will recommend the updated
>> specifications be approved and ratified by the RISC-V Technical
>> Steering Committee and the RISC-V Board of Directors.
>> SBI specification is non-ISA specifications and will evolve over time
>> with new extensions as long as they are backward compatible. Any such
>> proposals for new extensions can be included in the future releases
>> after proper discussions in the platform working group meetings.
>> Thanks to all the contributors for all their hard work.
>> [1] tech-unixplatformspec@...
>> [2]
>> Regards,
>> Atish Patra

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