[PATCH v4 1/4] RISC-V: Add Bitmanip/Scalar Crypto parsing from DT

[Evan Green]

On Thu, Jul 13, 2023 at 4:28 AM Conor Dooley <conor.dooley at microchip.com> wrote:
>
> On Thu, Jul 13, 2023 at 10:46:14AM +0200, Andrew Jones wrote:
> > On Wed, Jul 12, 2023 at 10:43:33AM -0700, Evan Green wrote:
> > > On Wed, Jul 12, 2023 at 3:39 AM Conor Dooley <conor.dooley at microchip.com> wrote:
> > > > On Wed, Jul 12, 2023 at 10:41:17AM +0200, Samuel Ortiz wrote:
> > > > > From: "Hongren (Zenithal) Zheng" <i at zenithal.me>
> > > > >
> > > > > Parse Zb/Zk related string from DT and output them to cpuinfo.
> > > >
> > > > One thing that has sprung to mind is that this is not limited to DT
> > > > anymore, since the information could in theory come from ACPI too.
> > > > Ditto the title I guess.
> > > >
> > > > > It is worth noting that the Scalar Crypto extension defines "zk" as a
> > > > > shorthand for the Zkn, Zkr and Zkt extensions. Since the Zkn one also
> > > > > implies the Zbkb, Zbkc and Zbkx extensions, simply passing the valid
> > > > > "zk" extension name through a DT will enable all of the  Zbkb, Zbkc,
> > > > > Zbkx, Zkn, Zkr and Zkt extensions.
> > > > >
> > > > > Also, since there currently is no mechanism to merge all enabled
> > > > > extensions, the generated cpuinfo output could be relatively large.
> > > > > For example, setting the "riscv,isa" DT property to "rv64imafdc_zk_zks"
> > > > > will generate the following cpuinfo output:
> > > > > "rv64imafdc_zbkb_zbkc_zbkx_zknd_zkne_zknh_zkr_zksed_zksh_zkt".
> > > >
> > > > On that note, I've created another version of what checking for
> > > > supersets could look like, since it'll be needed either by my series or
> > > > this one, depending on what gets merged first. I've yet to test the
> > > > dedicated extensions part of it, but I wanted to get this out before I
> > > > went looking at other fixes in the area.
> > > >
> > > > Evan, since it was you that commented on this stuff last time around,
> > > > could you take another look? I'm still not keen on the "subset_of"
> > > > arrays, but they're an improvement on what I had last time around for
> > > > sure.
> > > >
> > >
> > > This looks alright to me. At the risk of getting into bikeshedding
> > > territory, the only awkward bit of it is it composes the extensions in
> > > sort of the opposite way you'd expect. I tend to think of Zks as being
> > > comprised of {zbkb, zbkc, zksed, zksh},
> >
> > This is also the way I think of it, so, FWIW, I prefer the approach below,
> > where bundles are expanded.
>
> I took the patch Evan sent me off-list & have spun it into a "real"
> patch. I did some minor changes (c99 loop, __init marking) to match what
> the code was already doing and expanded it to work for the new property
> stuff.
> I'm not sure that match_isa_ext() needs to be a function, given the
> single user - it might be better refactored to drop the outer if & return
> whether a match was found.
> If done that would allow sharing the same function between isa string and
> dedicated property parsing. I left it intact for now. Might also be
> worth adding kerneldoc for that struct.
>
> -- >8 --
> From 8300b98e487e57d192bc9581c6a3639c40c52623 Mon Sep 17 00:00:00 2001
> From: Evan Green <evan at rivosinc.com>
> Date: Wed, 12 Jul 2023 10:36:15 -0700
> Subject: [PATCH] RISC-V: Add support Scalar Crypto using "bundled extensions"
>
> The Scalar Crypto specification defines Zk as a shorthand for the
> Zkn, Zkr and Zkt extensions. The same follows for both Zkn, Zks and Zbk,
> which are all shorthands for various other extensions. The detailed
> breakdown can be found in their dt-binding entries.
>
> Since Zkn also implies the Zbkb, Zbkc and Zbkx extensions, simply passing
> "zk" through a DT should enable all of Zbkb, Zbkc, Zbkx, Zkn, Zkr and Zkt.
> For example, setting the "riscv,isa" DT property to "rv64imafdc_zk"
> should generate the following cpuinfo output:
> "rv64imafdc_zicntr_zicsr_zifencei_zihpm_zbkb_zbkc_zbkx_zknd_zkne_zknh_zkr_zkt"
>
> riscv_isa_ext_data grows a pair of new members, to permit setting the
> relevant bits for "bundled" extensions, both while parsing the ISA string
> and the new dedicated extension properties
>
> Co-developed-by: Conor Dooley <conor.dooley at microchip.com>
> Signed-off-by: Conor Dooley <conor.dooley at microchip.com>
> ---
> There's basically none of the original patch left, so I have dropped the
> co-developed-bys and signed-off-bys from before. It does need one from
> you now though Evan!

Oops, I hadn't realized this was blocked on me!

Signed-off-by: Evan Green <evan at rivosinc.com>