Re: [PATCH v3 2/3] RISC-V: uapi: add HWCAP for Bitmanip/Scalar Crypto

Samuel Ortiz
2022-11-24T17:34:19Z

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@rivosinc.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
> >
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> > 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@rivosinc.com/
>
> 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?

Cheers,
Samuel.
>