On Thu, Nov 24, 2022 at 05:54:00PM +0000, Conor Dooley wrote: > On 24/11/2022 17:34, Samuel Ortiz wrote: > > On Thu, Nov 24, 2022 at 05:20:37PM +0000, Conor Dooley wrote: > >> On 24/11/2022 17:12, Samuel Ortiz wrote: > >>> [You don't often get email from sameo@xxxxxxxxxxxx. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ] > >>> > >>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > >>> > >>> On Thu, Nov 24, 2022 at 11:55:01AM +0000, Conor Dooley wrote: > >>>> On Thu, Nov 24, 2022 at 11:47:30AM +0100, Samuel Ortiz wrote: > >>>> > >>>>> Patch #1 is definitely needed regardless of which interface we pick for > >>>>> exposing the ISA strings to userspace. > >>>> > >>>> I took another look at #1, and I feel more confused about what > >>>> constitutes canonical order than I did before! If you know better than > >>>> I, and you probably do since you're interested in these 6 month old > >>>> patches, some insight would be appreciated! > >>> > >>> Assuming we don't go with hwcap, I dont think the order of the > >>> riscv_isa_ext_id enum matters that much? > >> > >> The chief put it in canonical order so that's good enough for me! > >> > >>> > >>> iiuc we're building the cpuinfo string from the riscv_isa_ext_data > >>> array, and I think the current code is incorrect: > >>> > >>> static struct riscv_isa_ext_data isa_ext_arr[] = { > >>> __RISCV_ISA_EXT_DATA(sscofpmf, RISCV_ISA_EXT_SSCOFPMF), > >>> __RISCV_ISA_EXT_DATA(sstc, RISCV_ISA_EXT_SSTC), > >>> __RISCV_ISA_EXT_DATA(svinval, RISCV_ISA_EXT_SVINVAL), > >>> __RISCV_ISA_EXT_DATA(svpbmt, RISCV_ISA_EXT_SVPBMT), > >>> __RISCV_ISA_EXT_DATA(zicbom, RISCV_ISA_EXT_ZICBOM), > >>> __RISCV_ISA_EXT_DATA(zihintpause, RISCV_ISA_EXT_ZIHINTPAUSE), > >>> __RISCV_ISA_EXT_DATA("", RISCV_ISA_EXT_MAX), > >>> }; > >>> > >>> zicbom and zihintpause should come before supervisor level extensions. > >>> I'm going to send a patch for that. > >> > >> idk, Palmer explicitly re-ordered this: > >> https://lore.kernel.org/linux-riscv/20220920204518.10988-1-palmer@xxxxxxxxxxxx/ > >> > >> By my reading of the isa manual, what Palmer did is correct as > >> those are not "Additional Standard Extensions". /shrug > > > > Hmm, by their name (Z[a-b]+) they are Additional Standard Extensions. > > What am I missing? > > Right, and this is where I get confused. Zam and Ztso *are* Additional > Standard Extensions, I think we can agree on that one? For those > extensions: > \chapter{``Ztso'' Standard Extension for Total Store Ordering, v0.1} > \chapter{``Zam'' Standard Extension for Misaligned Atomics, v0.1} > > They're also called out specifically in the table: > https://github.com/riscv/riscv-isa-manual/blob/master/src/naming.tex#L147 > > For Zihintpause however: > \chapter{``Zihintpause'' Pause Hint, Version 2.0} > > See what I mean? I looked at the specs for the bitmanip stuff and for > crypto, which both never mention being standard. I *think* this is because Zihintpause, bitmap and crypto are ratified but not yet part of an official spec (non-draft) release? > That table has the caption: > > The table also defines the canonical order in which extension names > > must appear in the name string, with top-to-bottom in table > > indicating first-to-last in the name string. > > It only calls out Zicsr, Zifencei, Zam and Ztso are being permitted > before Sdef, but as I said I am not a specs person, so perhaps some > of the extensions in question are intended to go there but have not > yet been merged into the isa manual doc. Zihintpause *is* in the > isa manual though but not specifically called out. > > Anyways, hopefully that at least helps with my line of thinking! It does, thanks. It's a little confusing, I agree. Cheers, Samuel.
