Status of the various RISC-V specification and policy
Hi All, Please find the below email from Stephano about the freeze announcement for various RISC-V specifications that will be part of privilege specification v1.12. All the review discussions are happening in the isa-dev mailing list. The review period will be open for 45 days ending Sunday October 31, 2021.
I just want to highlight the fact that the *H*, *V, SvPBMT, CMO extensions are frozen now. *This will help us merge some patches that have been present in the mailing list for a while.
Here are the ratification policy and extension life cycle documents present in the public. If you have any questions regarding this, please check with Mark/Stephano (cc'd).
Ratification policy: https://docs.google.com/document/d/1-UlaSGqk59_myeuPMrV9gyuaIgnmFzGh5Gfy_tpV...
Extension life cycle: https://docs.google.com/presentation/d/1nQ5uFb39KA6gvUi5SReWfIQSiRN7hp6z7ZPf...
-- Regards, Atish
Mail from Stephano: ---------------------------------------------------------------------------------- Subject: Privileged Specification 1.12 Freeze Milestone: Public Review
All,
The Privileged Specification version 1.12 has gone to public review. You can view the specification documents by following the links provided here: https://docs.google.com/document/d/1soGI__HytotOkoJtgTYD0nzf82Zhp5nWw1Mcgqvb...
Review discussion can be followed on the ISA-DEV mailing list here: https://groups.google.com/a/groups.riscv.org/g/isa-dev
The review period will be open for 45 days ending Sunday October 31, 2021.
We encourage all conversation to happen on this mailing list. Simply reply to the posts linked above with any questions or comments. If you feel that you have a topic that is best discussed internally with RISC-V members only, please contact me directly.
Kind Regards, Stephano -- Stephano Cetola Director of Technical Programs RISC-V International ----------------------------------------------------------------------------------------------------
On Tue, 21 Sep 2021 17:20:17 PDT (-0700), atishp@atishpatra.org wrote:
Hi All, Please find the below email from Stephano about the freeze announcement for various RISC-V specifications that will be part of privilege specification v1.12. All the review discussions are happening in the isa-dev mailing list. The review period will be open for 45 days ending Sunday October 31, 2021.
I just want to highlight the fact that the *H*, *V, SvPBMT, CMO extensions are frozen now. *This will help us merge some patches that have been present in the mailing list for a while.
Here are the ratification policy and extension life cycle documents present in the public. If you have any questions regarding this, please check with Mark/Stephano (cc'd).
Ratification policy: https://docs.google.com/document/d/1-UlaSGqk59_myeuPMrV9gyuaIgnmFzGh5Gfy_tpV...
Extension life cycle: https://docs.google.com/presentation/d/1nQ5uFb39KA6gvUi5SReWfIQSiRN7hp6z7ZPf...
I'm still buried after Plumbers, but one of the bits on my TODO list was to look throught the new definitions for frozen and stable. Nothing in this extension life cycle talks about the point at which compatibility will be maintained, which was really the central point behind frozen before.
Are there more concrete definitions somewhere?
the words in this document :
https://wiki.riscv.org/plugins/servlet/mobile?contentId=13098230#content/vie...
make it very clear when changes are allowed or not and likely or not.
if you think the verbiage is somehow ambiguous please help us make it better.
Mark -------- sent from a mobile device. please forgive any typos.
On Sep 27, 2021, at 8:50 AM, Palmer Dabbelt palmer@dabbelt.com wrote:
On Tue, 21 Sep 2021 17:20:17 PDT (-0700), atishp@atishpatra.org wrote:
Hi All, Please find the below email from Stephano about the freeze announcement for various RISC-V specifications that will be part of privilege specification v1.12. All the review discussions are happening in the isa-dev mailing list. The review period will be open for 45 days ending Sunday October 31, 2021.
I just want to highlight the fact that the *H*, *V, SvPBMT, CMO extensions are frozen now. *This will help us merge some patches that have been present in the mailing list for a while.
Here are the ratification policy and extension life cycle documents present in the public. If you have any questions regarding this, please check with Mark/Stephano (cc'd).
Ratification policy: https://docs.google.com/document/d/1-UlaSGqk59_myeuPMrV9gyuaIgnmFzGh5Gfy_tpV...
Extension life cycle: https://docs.google.com/presentation/d/1nQ5uFb39KA6gvUi5SReWfIQSiRN7hp6z7ZPf...
I'm still buried after Plumbers, but one of the bits on my TODO list was to look throught the new definitions for frozen and stable. Nothing in this extension life cycle talks about the point at which compatibility will be maintained, which was really the central point behind frozen before.
Are there more concrete definitions somewhere?
On Mon, 27 Sep 2021 08:57:15 PDT (-0700), markhimelstein@riscv.org wrote:
the words in this document :
https://wiki.riscv.org/plugins/servlet/mobile?contentId=13098230#content/vie...
make it very clear when changes are allowed or not and likely or not.
if you think the verbiage is somehow ambiguous please help us make it better.
I'm not really worried about changes, I'm worried about a committment to future compatibility. When we take code into the kernel (and most other core systems projects) we're taking on the burden of supporting (until someone can prove there are no more users), which is very difficult to do when the ISA changes in an incompatible fashion. The whole point of agreeing on the frozen thing was that it gave us a committment from the specifcation authors that the future ISA would be compatible with th frozen extensions.
We're already in this spot with the V extension and the whole stable thing, this definitaion of frozen looks very much like what was has led to the issues there. Saying the spec won't change really isn't meaningful, it's saying future specs will be compatible that's important. Nothing in this whole rule touches on compatibility, and I really don't want to end up in a bigger mess than we're already in.
(Also: some PGE subcontractor drove a crane into my house, so things are a bit chaotic on my end. If you have that list of what's officially frozen, can you send it out? I'll try to take a look ASAP, as then I can at least focus the discussion on what's relevant right now.)
Mark
sent from a mobile device. please forgive any typos.
On Sep 27, 2021, at 8:50 AM, Palmer Dabbelt palmer@dabbelt.com wrote:
On Tue, 21 Sep 2021 17:20:17 PDT (-0700), atishp@atishpatra.org wrote:
Hi All, Please find the below email from Stephano about the freeze announcement for various RISC-V specifications that will be part of privilege specification v1.12. All the review discussions are happening in the isa-dev mailing list. The review period will be open for 45 days ending Sunday October 31, 2021.
I just want to highlight the fact that the *H*, *V, SvPBMT, CMO extensions are frozen now. *This will help us merge some patches that have been present in the mailing list for a while.
Here are the ratification policy and extension life cycle documents present in the public. If you have any questions regarding this, please check with Mark/Stephano (cc'd).
Ratification policy: https://docs.google.com/document/d/1-UlaSGqk59_myeuPMrV9gyuaIgnmFzGh5Gfy_tpV...
Extension life cycle: https://docs.google.com/presentation/d/1nQ5uFb39KA6gvUi5SReWfIQSiRN7hp6z7ZPf...
I'm still buried after Plumbers, but one of the bits on my TODO list was to look throught the new definitions for frozen and stable. Nothing in this extension life cycle talks about the point at which compatibility will be maintained, which was really the central point behind frozen before.
Are there more concrete definitions somewhere?
On Tue, Sep 28, 2021 at 11:34 AM Palmer Dabbelt palmer@dabbelt.com wrote:
On Mon, 27 Sep 2021 08:57:15 PDT (-0700), markhimelstein@riscv.org wrote:
the words in this document :
https://wiki.riscv.org/plugins/servlet/mobile?contentId=13098230#content/vie...
make it very clear when changes are allowed or not and likely or not.
if you think the verbiage is somehow ambiguous please help us make it better.
I'm not really worried about changes, I'm worried about a committment to future compatibility. When we take code into the kernel (and most other core systems projects) we're taking on the burden of supporting (until someone can prove there are no more users), which is very difficult to do when the ISA changes in an incompatible fashion. The whole point of agreeing on the frozen thing was that it gave us a committment from the specifcation authors that the future ISA would be compatible with th frozen extensions.
We're already in this spot with the V extension and the whole stable thing, this definitaion of frozen looks very much like what was has led to the issues there. Saying the spec won't change really isn't meaningful, it's saying future specs will be compatible that's important. Nothing in this whole rule touches on compatibility, and I really don't want to end up in a bigger mess than we're already in.
(Also: some PGE subcontractor drove a crane into my house, so things are a bit chaotic on my end. If you have that list of what's officially frozen, can you send it out? I'll try to take a look ASAP, as then I can at least focus the discussion on what's relevant right now.)
Here is the list of the specs that are frozen. https://wiki.riscv.org/display/TECH/ISA+Extensions+On+Deck+for+Freeze+Milest... I will let Mark comment on the compatibility thing.
Mark
sent from a mobile device. please forgive any typos.
On Sep 27, 2021, at 8:50 AM, Palmer Dabbelt palmer@dabbelt.com wrote:
On Tue, 21 Sep 2021 17:20:17 PDT (-0700), atishp@atishpatra.org wrote:
Hi All, Please find the below email from Stephano about the freeze announcement for various RISC-V specifications that will be part of privilege specification v1.12. All the review discussions are happening in the isa-dev mailing list. The review period will be open for 45 days ending Sunday October 31, 2021.
I just want to highlight the fact that the *H*, *V, SvPBMT, CMO extensions are frozen now. *This will help us merge some patches that have been present in the mailing list for a while.
Here are the ratification policy and extension life cycle documents present in the public. If you have any questions regarding this, please check with Mark/Stephano (cc'd).
Ratification policy: https://docs.google.com/document/d/1-UlaSGqk59_myeuPMrV9gyuaIgnmFzGh5Gfy_tpV...
Extension life cycle: https://docs.google.com/presentation/d/1nQ5uFb39KA6gvUi5SReWfIQSiRN7hp6z7ZPf...
I'm still buried after Plumbers, but one of the bits on my TODO list was to look throught the new definitions for frozen and stable. Nothing in this extension life cycle talks about the point at which compatibility will be maintained, which was really the central point behind frozen before.
Are there more concrete definitions somewhere?
On Tue, 28 Sep 2021 13:05:53 PDT (-0700), atishp@atishpatra.org wrote:
On Tue, Sep 28, 2021 at 11:34 AM Palmer Dabbelt palmer@dabbelt.com wrote:
On Mon, 27 Sep 2021 08:57:15 PDT (-0700), markhimelstein@riscv.org wrote:
the words in this document :
https://wiki.riscv.org/plugins/servlet/mobile?contentId=13098230#content/vie...
make it very clear when changes are allowed or not and likely or not.
if you think the verbiage is somehow ambiguous please help us make it better.
I'm not really worried about changes, I'm worried about a committment to future compatibility. When we take code into the kernel (and most other core systems projects) we're taking on the burden of supporting (until someone can prove there are no more users), which is very difficult to do when the ISA changes in an incompatible fashion. The whole point of agreeing on the frozen thing was that it gave us a committment from the specifcation authors that the future ISA would be compatible with th frozen extensions.
We're already in this spot with the V extension and the whole stable thing, this definitaion of frozen looks very much like what was has led to the issues there. Saying the spec won't change really isn't meaningful, it's saying future specs will be compatible that's important. Nothing in this whole rule touches on compatibility, and I really don't want to end up in a bigger mess than we're already in.
(Also: some PGE subcontractor drove a crane into my house, so things are a bit chaotic on my end. If you have that list of what's officially frozen, can you send it out? I'll try to take a look ASAP, as then I can at least focus the discussion on what's relevant right now.)
Here is the list of the specs that are frozen. https://wiki.riscv.org/display/TECH/ISA+Extensions+On+Deck+for+Freeze+Milest...
How does that indicate what is frozen? I see "ISA Extensions On Deck for Freeze Milestone" as the title, which makes it sound like these are extension that are not yet frozen but will be eventually.
Scrolling down to the end of that list, it lists pointer masking. The best I can find is https://github.com/riscv/riscv-j-extension/blob/master/pointer-masking-propo... , which says "Version: v0.1-draft", which definately doesn't sound frozen. The README says "Working Draft of the RISC-V J Extension Specification", which also doesn't sound frozen.
I will let Mark comment on the compatibility thing.
Mark
sent from a mobile device. please forgive any typos.
On Sep 27, 2021, at 8:50 AM, Palmer Dabbelt palmer@dabbelt.com wrote:
On Tue, 21 Sep 2021 17:20:17 PDT (-0700), atishp@atishpatra.org wrote:
Hi All, Please find the below email from Stephano about the freeze announcement for various RISC-V specifications that will be part of privilege specification v1.12. All the review discussions are happening in the isa-dev mailing list. The review period will be open for 45 days ending Sunday October 31, 2021.
I just want to highlight the fact that the *H*, *V, SvPBMT, CMO extensions are frozen now. *This will help us merge some patches that have been present in the mailing list for a while.
Here are the ratification policy and extension life cycle documents present in the public. If you have any questions regarding this, please check with Mark/Stephano (cc'd).
Ratification policy: https://docs.google.com/document/d/1-UlaSGqk59_myeuPMrV9gyuaIgnmFzGh5Gfy_tpV...
Extension life cycle: https://docs.google.com/presentation/d/1nQ5uFb39KA6gvUi5SReWfIQSiRN7hp6z7ZPf...
I'm still buried after Plumbers, but one of the bits on my TODO list was to look throught the new definitions for frozen and stable. Nothing in this extension life cycle talks about the point at which compatibility will be maintained, which was really the central point behind frozen before.
Are there more concrete definitions somewhere?
-- Regards, Atish
On Tue, Sep 28, 2021 at 3:43 PM Palmer Dabbelt palmer@dabbelt.com wrote:
On Tue, 28 Sep 2021 13:05:53 PDT (-0700), atishp@atishpatra.org wrote:
On Tue, Sep 28, 2021 at 11:34 AM Palmer Dabbelt palmer@dabbelt.com wrote:
On Mon, 27 Sep 2021 08:57:15 PDT (-0700), markhimelstein@riscv.org wrote:
the words in this document :
https://wiki.riscv.org/plugins/servlet/mobile?contentId=13098230#content/vie...
make it very clear when changes are allowed or not and likely or not.
if you think the verbiage is somehow ambiguous please help us make it better.
I'm not really worried about changes, I'm worried about a committment to future compatibility. When we take code into the kernel (and most other core systems projects) we're taking on the burden of supporting (until someone can prove there are no more users), which is very difficult to do when the ISA changes in an incompatible fashion. The whole point of agreeing on the frozen thing was that it gave us a committment from the specifcation authors that the future ISA would be compatible with th frozen extensions.
We're already in this spot with the V extension and the whole stable thing, this definitaion of frozen looks very much like what was has led to the issues there. Saying the spec won't change really isn't meaningful, it's saying future specs will be compatible that's important. Nothing in this whole rule touches on compatibility, and I really don't want to end up in a bigger mess than we're already in.
(Also: some PGE subcontractor drove a crane into my house, so things are a bit chaotic on my end. If you have that list of what's officially frozen, can you send it out? I'll try to take a look ASAP, as then I can at least focus the discussion on what's relevant right now.)
Here is the list of the specs that are frozen. https://wiki.riscv.org/display/TECH/ISA+Extensions+On+Deck+for+Freeze+Milest...
How does that indicate what is frozen? I see "ISA Extensions On Deck for Freeze Milestone" as the title, which makes it sound like these are extension that are not yet frozen but will be eventually.
Any row with "top sheet" complete and "out for public review" is frozen. The life cycle document[1] that I shared earlier in this thread also says the same i.e. any specification that is out for public review is frozen. Stephano also sent out a public email about all the specifications that are frozen.
However, I understand that you need to do a little bit of deduction to understand what is frozen. @Stephano(already cc'd here)
Can you add a separate column clearly indicating that "Freeze" status for each of those specifications in the wiki link.
[1] https://docs.google.com/presentation/d/1nQ5uFb39KA6gvUi5SReWfIQSiRN7hp6z7ZPf...
Scrolling down to the end of that list, it lists pointer masking. The best I can find is https://github.com/riscv/riscv-j-extension/blob/master/pointer-masking-propo... , which says "Version: v0.1-draft", which definately doesn't sound frozen. The README says "Working Draft of the RISC-V J Extension Specification", which also doesn't sound frozen.
I will let Mark comment on the compatibility thing.
Mark
sent from a mobile device. please forgive any typos.
On Sep 27, 2021, at 8:50 AM, Palmer Dabbelt palmer@dabbelt.com wrote:
On Tue, 21 Sep 2021 17:20:17 PDT (-0700), atishp@atishpatra.org wrote:
Hi All, Please find the below email from Stephano about the freeze announcement for various RISC-V specifications that will be part of privilege specification v1.12. All the review discussions are happening in the isa-dev mailing list. The review period will be open for 45 days ending Sunday October 31, 2021.
I just want to highlight the fact that the *H*, *V, SvPBMT, CMO extensions are frozen now. *This will help us merge some patches that have been present in the mailing list for a while.
Here are the ratification policy and extension life cycle documents present in the public. If you have any questions regarding this, please check with Mark/Stephano (cc'd).
Ratification policy: https://docs.google.com/document/d/1-UlaSGqk59_myeuPMrV9gyuaIgnmFzGh5Gfy_tpV...
Extension life cycle: https://docs.google.com/presentation/d/1nQ5uFb39KA6gvUi5SReWfIQSiRN7hp6z7ZPf...
I'm still buried after Plumbers, but one of the bits on my TODO list was to look throught the new definitions for frozen and stable. Nothing in this extension life cycle talks about the point at which compatibility will be maintained, which was really the central point behind frozen before.
Are there more concrete definitions somewhere?
-- Regards, Atish
On Tue, 28 Sep 2021 16:23:56 PDT (-0700), atishp@atishpatra.org wrote:
On Tue, Sep 28, 2021 at 3:43 PM Palmer Dabbelt palmer@dabbelt.com wrote:
On Tue, 28 Sep 2021 13:05:53 PDT (-0700), atishp@atishpatra.org wrote:
On Tue, Sep 28, 2021 at 11:34 AM Palmer Dabbelt palmer@dabbelt.com wrote:
On Mon, 27 Sep 2021 08:57:15 PDT (-0700), markhimelstein@riscv.org wrote:
the words in this document :
https://wiki.riscv.org/plugins/servlet/mobile?contentId=13098230#content/vie...
make it very clear when changes are allowed or not and likely or not.
if you think the verbiage is somehow ambiguous please help us make it better.
I'm not really worried about changes, I'm worried about a committment to future compatibility. When we take code into the kernel (and most other core systems projects) we're taking on the burden of supporting (until someone can prove there are no more users), which is very difficult to do when the ISA changes in an incompatible fashion. The whole point of agreeing on the frozen thing was that it gave us a committment from the specifcation authors that the future ISA would be compatible with th frozen extensions.
We're already in this spot with the V extension and the whole stable thing, this definitaion of frozen looks very much like what was has led to the issues there. Saying the spec won't change really isn't meaningful, it's saying future specs will be compatible that's important. Nothing in this whole rule touches on compatibility, and I really don't want to end up in a bigger mess than we're already in.
(Also: some PGE subcontractor drove a crane into my house, so things are a bit chaotic on my end. If you have that list of what's officially frozen, can you send it out? I'll try to take a look ASAP, as then I can at least focus the discussion on what's relevant right now.)
Here is the list of the specs that are frozen. https://wiki.riscv.org/display/TECH/ISA+Extensions+On+Deck+for+Freeze+Milest...
How does that indicate what is frozen? I see "ISA Extensions On Deck for Freeze Milestone" as the title, which makes it sound like these are extension that are not yet frozen but will be eventually.
Any row with "top sheet" complete and "out for public review" is frozen. The life cycle document[1] that I shared earlier in this thread also says the same i.e. any specification that is out for public review is frozen. Stephano also sent out a public email about all the specifications that are frozen.
However, I understand that you need to do a little bit of deduction to understand what is frozen. @Stephano(already cc'd here)
Can you add a separate column clearly indicating that "Freeze" status for each of those specifications in the wiki link.
Is meant to be the complete list of what is frozen?
I'd expect any list of things that are frozen to contain the specs we've been working with for a while (priv-1.11, all the user 2.0 specs, etc). There was some talk about the SBI stuff that was called out as frozen before this process not actually being frozen, are those other specs in the same spot and if so are they going to end up being frozen?
That reminds me about this other set of specifications, sometimes called software specifications. There's a list of "Non-ISA Extensions On Deck for Freeze Milestone" here: https://wiki.riscv.org/display/TECH/Non-ISA+Extensions+On+Deck+for+Freeze+Mi... . That's got a frozen column in the table, but the table itself is pretty much empty. We've had a bunch of confusing statements about those specifications being frozen, were the statements inaccurate, is that table inaccurate, and will that table be an additional list of frozen specifications?
[1] https://docs.google.com/presentation/d/1nQ5uFb39KA6gvUi5SReWfIQSiRN7hp6z7ZPf...
Scrolling down to the end of that list, it lists pointer masking. The best I can find is https://github.com/riscv/riscv-j-extension/blob/master/pointer-masking-propo... , which says "Version: v0.1-draft", which definately doesn't sound frozen. The README says "Working Draft of the RISC-V J Extension Specification", which also doesn't sound frozen.
I will let Mark comment on the compatibility thing.
Mark
sent from a mobile device. please forgive any typos.
On Sep 27, 2021, at 8:50 AM, Palmer Dabbelt palmer@dabbelt.com wrote:
On Tue, 21 Sep 2021 17:20:17 PDT (-0700), atishp@atishpatra.org wrote: > Hi All, > Please find the below email from Stephano about the freeze announcement for > various RISC-V specifications that will be part of privilege specification > v1.12. > All the review discussions are happening in the isa-dev mailing list. The > review period will be open for 45 days ending Sunday October 31, 2021. > > I just want to highlight the fact that the *H*, *V, SvPBMT, CMO extensions > are frozen now. *This will help us merge some patches that have been > present in the mailing list for a while. > > Here are the ratification policy and extension life cycle documents present > in the public. If you have any questions regarding this, please check with > Mark/Stephano (cc'd). > > Ratification policy: > https://docs.google.com/document/d/1-UlaSGqk59_myeuPMrV9gyuaIgnmFzGh5Gfy_tpV... > > Extension life cycle: > https://docs.google.com/presentation/d/1nQ5uFb39KA6gvUi5SReWfIQSiRN7hp6z7ZPf...
I'm still buried after Plumbers, but one of the bits on my TODO list was to look throught the new definitions for frozen and stable. Nothing in this extension life cycle talks about the point at which compatibility will be maintained, which was really the central point behind frozen before.
Are there more concrete definitions somewhere?
-- Regards, Atish
-- Regards, Atish
Palmer,
Thank you for your input.
Our strong intention is to not change specs once frozen. I speak for the committees here and say that, in our opinion, declaring something frozen sets a very high bar for making any changes and is sufficient to allow code supporting an extension to be upstreamed. Of course if an unexpected and significant issue is discovered during the public review that absolutely must be addressed and cannot be deferred to a future extension (where the cost of not addressing the issue exceeds the cost of addressing it. for example introduces security vulnerabilities), then we will do so, as anyone should expect from a public review.
We do not have versions of extensions. If an extension has a problem once ratified, we will issue errata. All implementers have to publish the errata if they use branding. We may release a new extension with the bulk of the original extension plus the errata fix at some future date.
New extensions reserve the right to be incompatible with existing extensions but our philosophy is very much to minimize that and only allow the rare well-justified exceptions. Reasons may include errata, security issues discovered, or new functionality we need to add that justifies creating an incompatibility, etc.
What specifically do you see as an issue? What are you blocked on by our conventions? We need specific details to resolve any issues. Right now, I don't feel I have enough information from you.
Thanks
Mark
P.S. We had some situations in the past, in part due to vendors not waiting for the specification processes to conclude, where implementers implemented non-confoming chips either with vendor-specific extensions using reserved opcodes and state, or implementing early drafts of standards-track proposals in the development state (will likely change). This is in the past and resolved. Anyone implementing non-standard extensions must advertise them as such and make it clear that these are not standard RISC-V extensions: this should make it clear for upstream projects that they will be dealing with the respective vendors for support and maintenance, and that any code implementing support for these extensions will be different from what covers the respective standard extensions. Whether upstream projects accept such changes, and what conditions they stipulate for acceptance of these changes, are beyond the control of RISC-V. We also, as I have described to you many times, have instituted mandatory standards specification states for the front page of each specification to ensure clarity (any divergence from this is a bug and we work to fix these quickly).
On Tue, Sep 28, 2021 at 11:34 AM Palmer Dabbelt palmer@dabbelt.com wrote:
On Mon, 27 Sep 2021 08:57:15 PDT (-0700), markhimelstein@riscv.org wrote:
the words in this document :
https://wiki.riscv.org/plugins/servlet/mobile?contentId=13098230#content/vie...
make it very clear when changes are allowed or not and likely or not.
if you think the verbiage is somehow ambiguous please help us make it
better.
I'm not really worried about changes, I'm worried about a committment to future compatibility. When we take code into the kernel (and most other core systems projects) we're taking on the burden of supporting (until someone can prove there are no more users), which is very difficult to do when the ISA changes in an incompatible fashion. The whole point of agreeing on the frozen thing was that it gave us a committment from the specifcation authors that the future ISA would be compatible with th frozen extensions.
We're already in this spot with the V extension and the whole stable thing, this definitaion of frozen looks very much like what was has led to the issues there. Saying the spec won't change really isn't meaningful, it's saying future specs will be compatible that's important. Nothing in this whole rule touches on compatibility, and I really don't want to end up in a bigger mess than we're already in.
(Also: some PGE subcontractor drove a crane into my house, so things are a bit chaotic on my end. If you have that list of what's officially frozen, can you send it out? I'll try to take a look ASAP, as then I can at least focus the discussion on what's relevant right now.)
Mark
sent from a mobile device. please forgive any typos.
On Sep 27, 2021, at 8:50 AM, Palmer Dabbelt palmer@dabbelt.com wrote:
On Tue, 21 Sep 2021 17:20:17 PDT (-0700), atishp@atishpatra.org wrote:
Hi All, Please find the below email from Stephano about the freeze
announcement for
various RISC-V specifications that will be part of privilege
specification
v1.12. All the review discussions are happening in the isa-dev mailing list.
The
review period will be open for 45 days ending Sunday October 31, 2021.
I just want to highlight the fact that the *H*, *V, SvPBMT, CMO
extensions
are frozen now. *This will help us merge some patches that have been present in the mailing list for a while.
Here are the ratification policy and extension life cycle documents
present
in the public. If you have any questions regarding this, please check
with
Mark/Stephano (cc'd).
Ratification policy:
https://docs.google.com/document/d/1-UlaSGqk59_myeuPMrV9gyuaIgnmFzGh5Gfy_tpV...
Extension life cycle:
https://docs.google.com/presentation/d/1nQ5uFb39KA6gvUi5SReWfIQSiRN7hp6z7ZPf...
I'm still buried after Plumbers, but one of the bits on my TODO list
was to look throught the new definitions for frozen and stable. Nothing in this extension life cycle talks about the point at which compatibility will be maintained, which was really the central point behind frozen before.
Are there more concrete definitions somewhere?
On Thu, 30 Sep 2021 08:06:42 PDT (-0700), markhimelstein@riscv.org wrote:
Palmer,
Thank you for your input.
Our strong intention is to not change specs once frozen. I speak for the committees here and say that, in our opinion, declaring something frozen sets a very high bar for making any changes and is sufficient to allow code supporting an extension to be upstreamed. Of course if an unexpected and significant issue is discovered during the public review that absolutely must be addressed and cannot be deferred to a future extension (where the cost of not addressing the issue exceeds the cost of addressing it. for example introduces security vulnerabilities), then we will do so, as anyone should expect from a public review.
We do not have versions of extensions. If an extension has a problem once ratified, we will issue errata. All implementers have to publish the errata if they use branding. We may release a new extension with the bulk of the original extension plus the errata fix at some future date.
This is probably at the core of my confusion here.
At the preface of the user ISA there is a table with the headings "Extension", "Version", and "Frozen"; contains a list of letters that look like extension name; and contains a list of numbers that look like versions of those extensions.
That nomenclature seems to carry on to some more recent specifications. For example the first page of https://github.com/riscv/riscv-v-spec/releases/download/v1.0/riscv-v-spec-1.... (tagged 11 days ago) is
RISC-V "V" Vector Extension Version 1.0
I'm happy to answer the rest of the questions here, but I think trying to get on the same page about what is versioned and is proabbly the first step because that's a pretty key component of my worries.
New extensions reserve the right to be incompatible with existing extensions but our philosophy is very much to minimize that and only allow the rare well-justified exceptions. Reasons may include errata, security issues discovered, or new functionality we need to add that justifies creating an incompatibility, etc.
What specifically do you see as an issue? What are you blocked on by our conventions? We need specific details to resolve any issues. Right now, I don't feel I have enough information from you.
Thanks
Mark
P.S. We had some situations in the past, in part due to vendors not waiting for the specification processes to conclude, where implementers implemented non-confoming chips either with vendor-specific extensions using reserved opcodes and state, or implementing early drafts of standards-track proposals in the development state (will likely change). This is in the past and resolved. Anyone implementing non-standard extensions must advertise them as such and make it clear that these are not standard RISC-V extensions: this should make it clear for upstream projects that they will be dealing with the respective vendors for support and maintenance, and that any code implementing support for these extensions will be different from what covers the respective standard extensions. Whether upstream projects accept such changes, and what conditions they stipulate for acceptance of these changes, are beyond the control of RISC-V. We also, as I have described to you many times, have instituted mandatory standards specification states for the front page of each specification to ensure clarity (any divergence from this is a bug and we work to fix these quickly).
On Tue, Sep 28, 2021 at 11:34 AM Palmer Dabbelt palmer@dabbelt.com wrote:
On Mon, 27 Sep 2021 08:57:15 PDT (-0700), markhimelstein@riscv.org wrote:
the words in this document :
https://wiki.riscv.org/plugins/servlet/mobile?contentId=13098230#content/vie...
make it very clear when changes are allowed or not and likely or not.
if you think the verbiage is somehow ambiguous please help us make it
better.
I'm not really worried about changes, I'm worried about a committment to future compatibility. When we take code into the kernel (and most other core systems projects) we're taking on the burden of supporting (until someone can prove there are no more users), which is very difficult to do when the ISA changes in an incompatible fashion. The whole point of agreeing on the frozen thing was that it gave us a committment from the specifcation authors that the future ISA would be compatible with th frozen extensions.
We're already in this spot with the V extension and the whole stable thing, this definitaion of frozen looks very much like what was has led to the issues there. Saying the spec won't change really isn't meaningful, it's saying future specs will be compatible that's important. Nothing in this whole rule touches on compatibility, and I really don't want to end up in a bigger mess than we're already in.
(Also: some PGE subcontractor drove a crane into my house, so things are a bit chaotic on my end. If you have that list of what's officially frozen, can you send it out? I'll try to take a look ASAP, as then I can at least focus the discussion on what's relevant right now.)
Mark
sent from a mobile device. please forgive any typos.
On Sep 27, 2021, at 8:50 AM, Palmer Dabbelt palmer@dabbelt.com wrote:
On Tue, 21 Sep 2021 17:20:17 PDT (-0700), atishp@atishpatra.org wrote:
Hi All, Please find the below email from Stephano about the freeze
announcement for
various RISC-V specifications that will be part of privilege
specification
v1.12. All the review discussions are happening in the isa-dev mailing list.
The
review period will be open for 45 days ending Sunday October 31, 2021.
I just want to highlight the fact that the *H*, *V, SvPBMT, CMO
extensions
are frozen now. *This will help us merge some patches that have been present in the mailing list for a while.
Here are the ratification policy and extension life cycle documents
present
in the public. If you have any questions regarding this, please check
with
Mark/Stephano (cc'd).
Ratification policy:
https://docs.google.com/document/d/1-UlaSGqk59_myeuPMrV9gyuaIgnmFzGh5Gfy_tpV...
Extension life cycle:
https://docs.google.com/presentation/d/1nQ5uFb39KA6gvUi5SReWfIQSiRN7hp6z7ZPf...
I'm still buried after Plumbers, but one of the bits on my TODO list
was to look throught the new definitions for frozen and stable. Nothing in this extension life cycle talks about the point at which compatibility will be maintained, which was really the central point behind frozen before.
Are there more concrete definitions somewhere?
The following is the extension lifecycle. It includes the official names going forward for each phase. We are trying to resolve any confusion naming and numbering and are still in progress of this evolution:
https://docs.google.com/presentation/d/1nQ5uFb39KA6gvUi5SReWfIQSiRN7hp6z7ZPf...
Again, if we can improve anything to make it clearer or if we got something wrong, please let us know.
Mark
On Thu, Sep 30, 2021 at 10:30 AM Palmer Dabbelt palmer@dabbelt.com wrote:
On Thu, 30 Sep 2021 08:06:42 PDT (-0700), markhimelstein@riscv.org wrote:
Palmer,
Thank you for your input.
Our strong intention is to not change specs once frozen. I speak for the committees here and say that, in our opinion, declaring something frozen sets a very high bar for making any changes and is sufficient to allow
code
supporting an extension to be upstreamed. Of course if an unexpected and significant issue is discovered during the public review that absolutely must be addressed and cannot be deferred to a future extension (where the cost of not addressing the issue exceeds the cost of addressing it. for example introduces security vulnerabilities), then we will do so, as
anyone
should expect from a public review.
We do not have versions of extensions. If an extension has a problem once ratified, we will issue errata. All implementers have to publish the
errata
if they use branding. We may release a new extension with the bulk of the original extension plus the errata fix at some future date.
This is probably at the core of my confusion here.
At the preface of the user ISA there is a table with the headings "Extension", "Version", and "Frozen"; contains a list of letters that look like extension name; and contains a list of numbers that look like versions of those extensions.
That nomenclature seems to carry on to some more recent specifications. For example the first page of
https://github.com/riscv/riscv-v-spec/releases/download/v1.0/riscv-v-spec-1.... (tagged 11 days ago) is
RISC-V "V" Vector Extension Version 1.0I'm happy to answer the rest of the questions here, but I think trying to get on the same page about what is versioned and is proabbly the first step because that's a pretty key component of my worries.
New extensions reserve the right to be incompatible with existing extensions but our philosophy is very much to minimize that and only
allow
the rare well-justified exceptions. Reasons may include errata, security issues discovered, or new functionality we need to add that justifies creating an incompatibility, etc.
What specifically do you see as an issue? What are you blocked on by our conventions? We need specific details to resolve any issues. Right now, I don't feel I have enough information from you.
Thanks
Mark
P.S. We had some situations in the past, in part due to vendors not
waiting
for the specification processes to conclude, where implementers
implemented
non-confoming chips either with vendor-specific extensions using reserved opcodes and state, or implementing early drafts of standards-track proposals in the development state (will likely change). This is in the past and resolved. Anyone implementing non-standard extensions must advertise them as such and make it clear that these are not standard
RISC-V
extensions: this should make it clear for upstream projects that they
will
be dealing with the respective vendors for support and maintenance, and that any code implementing support for these extensions will be different from what covers the respective standard extensions. Whether upstream projects accept such changes, and what conditions they stipulate for acceptance of these changes, are beyond the control of RISC-V. We also,
as
I have described to you many times, have instituted mandatory standards specification states for the front page of each specification to ensure clarity (any divergence from this is a bug and we work to fix these quickly).
On Tue, Sep 28, 2021 at 11:34 AM Palmer Dabbelt palmer@dabbelt.com
wrote:
On Mon, 27 Sep 2021 08:57:15 PDT (-0700), markhimelstein@riscv.org
wrote:
the words in this document :
https://wiki.riscv.org/plugins/servlet/mobile?contentId=13098230#content/vie...
make it very clear when changes are allowed or not and likely or not.
if you think the verbiage is somehow ambiguous please help us make it
better.
I'm not really worried about changes, I'm worried about a committment to future compatibility. When we take code into the kernel (and most other core systems projects) we're taking on the burden of supporting (until someone can prove there are no more users), which is very difficult to do when the ISA changes in an incompatible fashion. The whole point of agreeing on the frozen thing was that it gave us a committment from the specifcation authors that the future ISA would be compatible with th frozen extensions.
We're already in this spot with the V extension and the whole stable thing, this definitaion of frozen looks very much like what was has led to the issues there. Saying the spec won't change really isn't meaningful, it's saying future specs will be compatible that's important. Nothing in this whole rule touches on compatibility, and I really don't want to end up in a bigger mess than we're already in.
(Also: some PGE subcontractor drove a crane into my house, so things are a bit chaotic on my end. If you have that list of what's officially frozen, can you send it out? I'll try to take a look ASAP, as then I can at least focus the discussion on what's relevant right now.)
Mark
sent from a mobile device. please forgive any typos.
On Sep 27, 2021, at 8:50 AM, Palmer Dabbelt palmer@dabbelt.com
wrote:
On Tue, 21 Sep 2021 17:20:17 PDT (-0700), atishp@atishpatra.org
wrote:
Hi All, Please find the below email from Stephano about the freeze
announcement for
various RISC-V specifications that will be part of privilege
specification
v1.12. All the review discussions are happening in the isa-dev mailing
list.
The
review period will be open for 45 days ending Sunday October 31,
I just want to highlight the fact that the *H*, *V, SvPBMT, CMO
extensions
are frozen now. *This will help us merge some patches that have been present in the mailing list for a while.
Here are the ratification policy and extension life cycle documents
present
in the public. If you have any questions regarding this, please
check
with
Mark/Stephano (cc'd).
Ratification policy:
https://docs.google.com/document/d/1-UlaSGqk59_myeuPMrV9gyuaIgnmFzGh5Gfy_tpV...
Extension life cycle:
https://docs.google.com/presentation/d/1nQ5uFb39KA6gvUi5SReWfIQSiRN7hp6z7ZPf...
I'm still buried after Plumbers, but one of the bits on my TODO list
was to look throught the new definitions for frozen and stable.
Nothing in
this extension life cycle talks about the point at which compatibility
will
be maintained, which was really the central point behind frozen before.
Are there more concrete definitions somewhere?
On Thu, 30 Sep 2021 10:38:02 PDT (-0700), markhimelstein@riscv.org wrote:
The following is the extension lifecycle. It includes the official names going forward for each phase. We are trying to resolve any confusion naming and numbering and are still in progress of this evolution:
https://docs.google.com/presentation/d/1nQ5uFb39KA6gvUi5SReWfIQSiRN7hp6z7ZPf...
Again, if we can improve anything to make it clearer or if we got something wrong, please let us know.
That is, unfortunately, even more confusing.
Slide 3 lists the milestones, but that uses very different terms than the "Specification States" wiki entry I was linked to earlier as the canonical definition of the process. I'm also now less sure about what exactly is being frozen, as the slides seem to mix up extension and specification (which is the core of what I'm worried about).
Looking at slide 4 (titled "Extension Lifecycle"), I see a bunch of version number looking strings (things like "v0.1" and "v1.0-rcN (final)"). Are those versions, and if so what do they version?
It also says "v1.0 (ratified)" with an arrow pointing directly after "TSC Ratification Review & Vote", but in the v-1.0 tag I see "Once ratified, the spec will be given version 2.0." Are these version-number-looking strings supposed to be things that exist within the same namespace?
Just loking over the slide again I see "New or Changed Features Specification Development become a new extension -- Go back to the top left". That sort of seems like something that might help answer some of my core questionsn here around what's allowed to change when, but I'm genuinely not sure how to parse the words. Might not be the most important thing to focus on now, though.
Mark
On Thu, Sep 30, 2021 at 10:30 AM Palmer Dabbelt palmer@dabbelt.com wrote:
On Thu, 30 Sep 2021 08:06:42 PDT (-0700), markhimelstein@riscv.org wrote:
Palmer,
Thank you for your input.
Our strong intention is to not change specs once frozen. I speak for the committees here and say that, in our opinion, declaring something frozen sets a very high bar for making any changes and is sufficient to allow
code
supporting an extension to be upstreamed. Of course if an unexpected and significant issue is discovered during the public review that absolutely must be addressed and cannot be deferred to a future extension (where the cost of not addressing the issue exceeds the cost of addressing it. for example introduces security vulnerabilities), then we will do so, as
anyone
should expect from a public review.
We do not have versions of extensions. If an extension has a problem once ratified, we will issue errata. All implementers have to publish the
errata
if they use branding. We may release a new extension with the bulk of the original extension plus the errata fix at some future date.
This is probably at the core of my confusion here.
At the preface of the user ISA there is a table with the headings "Extension", "Version", and "Frozen"; contains a list of letters that look like extension name; and contains a list of numbers that look like versions of those extensions.
That nomenclature seems to carry on to some more recent specifications. For example the first page of
https://github.com/riscv/riscv-v-spec/releases/download/v1.0/riscv-v-spec-1.... (tagged 11 days ago) is
RISC-V "V" Vector Extension Version 1.0I'm happy to answer the rest of the questions here, but I think trying to get on the same page about what is versioned and is proabbly the first step because that's a pretty key component of my worries.
New extensions reserve the right to be incompatible with existing extensions but our philosophy is very much to minimize that and only
allow
the rare well-justified exceptions. Reasons may include errata, security issues discovered, or new functionality we need to add that justifies creating an incompatibility, etc.
What specifically do you see as an issue? What are you blocked on by our conventions? We need specific details to resolve any issues. Right now, I don't feel I have enough information from you.
Thanks
Mark
P.S. We had some situations in the past, in part due to vendors not
waiting
for the specification processes to conclude, where implementers
implemented
non-confoming chips either with vendor-specific extensions using reserved opcodes and state, or implementing early drafts of standards-track proposals in the development state (will likely change). This is in the past and resolved. Anyone implementing non-standard extensions must advertise them as such and make it clear that these are not standard
RISC-V
extensions: this should make it clear for upstream projects that they
will
be dealing with the respective vendors for support and maintenance, and that any code implementing support for these extensions will be different from what covers the respective standard extensions. Whether upstream projects accept such changes, and what conditions they stipulate for acceptance of these changes, are beyond the control of RISC-V. We also,
as
I have described to you many times, have instituted mandatory standards specification states for the front page of each specification to ensure clarity (any divergence from this is a bug and we work to fix these quickly).
On Tue, Sep 28, 2021 at 11:34 AM Palmer Dabbelt palmer@dabbelt.com
wrote:
On Mon, 27 Sep 2021 08:57:15 PDT (-0700), markhimelstein@riscv.org
wrote:
the words in this document :
https://wiki.riscv.org/plugins/servlet/mobile?contentId=13098230#content/vie...
make it very clear when changes are allowed or not and likely or not.
if you think the verbiage is somehow ambiguous please help us make it
better.
I'm not really worried about changes, I'm worried about a committment to future compatibility. When we take code into the kernel (and most other core systems projects) we're taking on the burden of supporting (until someone can prove there are no more users), which is very difficult to do when the ISA changes in an incompatible fashion. The whole point of agreeing on the frozen thing was that it gave us a committment from the specifcation authors that the future ISA would be compatible with th frozen extensions.
We're already in this spot with the V extension and the whole stable thing, this definitaion of frozen looks very much like what was has led to the issues there. Saying the spec won't change really isn't meaningful, it's saying future specs will be compatible that's important. Nothing in this whole rule touches on compatibility, and I really don't want to end up in a bigger mess than we're already in.
(Also: some PGE subcontractor drove a crane into my house, so things are a bit chaotic on my end. If you have that list of what's officially frozen, can you send it out? I'll try to take a look ASAP, as then I can at least focus the discussion on what's relevant right now.)
Mark
sent from a mobile device. please forgive any typos.
On Sep 27, 2021, at 8:50 AM, Palmer Dabbelt palmer@dabbelt.com
wrote:
On Tue, 21 Sep 2021 17:20:17 PDT (-0700), atishp@atishpatra.org
wrote:
> Hi All, > Please find the below email from Stephano about the freeze
announcement for
> various RISC-V specifications that will be part of privilege
specification
> v1.12. > All the review discussions are happening in the isa-dev mailing
list.
The
> review period will be open for 45 days ending Sunday October 31,
> > I just want to highlight the fact that the *H*, *V, SvPBMT, CMO
extensions
> are frozen now. *This will help us merge some patches that have been > present in the mailing list for a while. > > Here are the ratification policy and extension life cycle documents
present
> in the public. If you have any questions regarding this, please
check
with
> Mark/Stephano (cc'd). > > Ratification policy: >
https://docs.google.com/document/d/1-UlaSGqk59_myeuPMrV9gyuaIgnmFzGh5Gfy_tpV...
> > Extension life cycle: >
https://docs.google.com/presentation/d/1nQ5uFb39KA6gvUi5SReWfIQSiRN7hp6z7ZPf...
I'm still buried after Plumbers, but one of the bits on my TODO list
was to look throught the new definitions for frozen and stable.
Nothing in
this extension life cycle talks about the point at which compatibility
will
be maintained, which was really the central point behind frozen before.
Are there more concrete definitions somewhere?
participants (3)
-
Atish Patra -
Mark Himelstein -
Palmer Dabbelt