From: Conor Dooley <conor@kernel.org>
To: Andrew Jones <andrew.jones@oss.qualcomm.com>
Cc: "Guodong Xu" <guodong@riscstar.com>,
linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
kvm-riscv@lists.infradead.org, "Paul Walmsley" <pjw@kernel.org>,
"Palmer Dabbelt" <palmer@dabbelt.com>,
"Anup Patel" <anup@brainfault.org>,
"Clément Léger" <cleger@rivosinc.com>,
"Conor Dooley" <conor.dooley@microchip.com>,
"Charlie Jenkins" <charlie@rivosinc.com>,
"Charlie Jenkins" <thecharlesjenkins@gmail.com>,
"Samuel Holland" <samuel.holland@sifive.com>
Subject: Re: [RFC PATCH v1 04/11] riscv: Add B to hwcap
Date: Fri, 6 Mar 2026 18:50:20 +0000 [thread overview]
Message-ID: <20260306-extradite-vexingly-707b5633ef03@spud> (raw)
In-Reply-To: <z5bm4uoryuvz5cnsdl37pqmctkqrxw3kk7vqnb3vopnyg2mhl2@ctwdfkgahjfk>
[-- Attachment #1.1: Type: text/plain, Size: 985 bytes --]
On Fri, Mar 06, 2026 at 12:27:50PM -0600, Andrew Jones wrote:
> On Fri, Mar 06, 2026 at 10:17:19AM +0800, Guodong Xu wrote:
> > + /*
> > + * B is functionally a bundle (Zba + Zbb + Zbs,
> > + * no additional instructions). We use SUPERSET
> > + * instead of BUNDLE because B needs a valid ext
> > + * id for isa2hwcap[] to set COMPAT_HWCAP_ISA_B.
What's the actual rationale for it working like that?
Why shouldn't bundles appear in cpuinfo etc, I forget entirely why we
did it this way. Feels like it'd be easier for users, no?
2023 me might disagree, but 2026 me doesn't see the value in hiding these
extensions. All I can think of was me being very negative, and hedging
against bad software checking for zkn and not checking for the subsets,
and breaking if the dt listed the entire subset but not zkn. That, or
not wanting to implement code that looked for subset extensions and
populated the relevant bundle if the bundle itself was missing but all
components were there.
[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]
[-- Attachment #2: Type: text/plain, Size: 161 bytes --]
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
next prev parent reply other threads:[~2026-03-06 18:50 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-06 0:23 [RFC PATCH v1 00/11] riscv: hwprobe: Introduce rva23u64 base behavior Andrew Jones
2026-02-06 0:23 ` [RFC PATCH v1 01/11] riscv: hwprobe: add support for RISCV_HWPROBE_KEY_IMA_EXT_1 Andrew Jones
2026-02-06 0:23 ` [RFC PATCH v1 02/11] RISC-V: Add Zicclsm to cpufeature and hwprobe Andrew Jones
2026-02-06 0:23 ` [RFC PATCH v1 03/11] riscv: Standardize extension capitilization Andrew Jones
2026-02-06 0:23 ` [RFC PATCH v1 04/11] riscv: Add B to hwcap Andrew Jones
2026-02-21 10:49 ` Guodong Xu
2026-02-24 23:04 ` Andrew Jones
2026-03-06 2:17 ` Guodong Xu
2026-03-06 18:27 ` Andrew Jones
2026-03-06 18:50 ` Conor Dooley [this message]
2026-03-06 19:04 ` Andrew Jones
2026-02-06 0:23 ` [RFC PATCH v1 05/11] riscv: hwprobe.rst: Replace tabs with spaces Andrew Jones
2026-02-06 0:23 ` [RFC PATCH v1 06/11] riscv: Add Ziccamoa, Ziccif, Ziccrse, and Za64rs to hwprobe Andrew Jones
2026-02-21 10:50 ` Guodong Xu
2026-02-24 23:22 ` Andrew Jones
2026-02-06 0:23 ` [RFC PATCH v1 07/11] riscv: Export have_user_pmlen* booleans Andrew Jones
2026-02-21 10:50 ` Guodong Xu
2026-02-24 23:32 ` Andrew Jones
2026-02-06 0:23 ` [RFC PATCH v1 08/11] riscv: hwprobe: Introduce rva23u64 base behavior Andrew Jones
2026-02-08 16:15 ` Andrew Jones
2026-02-21 10:51 ` Guodong Xu
2026-02-25 0:03 ` Andrew Jones
2026-03-06 12:29 ` Guodong Xu
2026-03-06 18:31 ` Andrew Jones
2026-03-06 12:08 ` Guodong Xu
2026-03-06 18:33 ` Andrew Jones
2026-02-06 0:23 ` [RFC PATCH v1 09/11] riscv: selftests: hwprobe: Check rva23u64 consistency Andrew Jones
2026-02-06 0:23 ` [RFC PATCH v1 10/11] riscv: /proc/cpuinfo: Add rva23 bases to output Andrew Jones
2026-02-21 10:52 ` Guodong Xu
2026-02-25 0:08 ` Andrew Jones
2026-03-06 12:47 ` Guodong Xu
2026-03-06 18:34 ` Andrew Jones
2026-02-06 0:23 ` [RFC PATCH v1 11/11] riscv: /proc/cpuinfo: Also output rva20 and rva22 isa bases Andrew Jones
2026-03-05 0:58 ` [RFC PATCH v1 00/11] riscv: hwprobe: Introduce rva23u64 base behavior Charlie Jenkins
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260306-extradite-vexingly-707b5633ef03@spud \
--to=conor@kernel.org \
--cc=andrew.jones@oss.qualcomm.com \
--cc=anup@brainfault.org \
--cc=charlie@rivosinc.com \
--cc=cleger@rivosinc.com \
--cc=conor.dooley@microchip.com \
--cc=guodong@riscstar.com \
--cc=kvm-riscv@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-riscv@lists.infradead.org \
--cc=palmer@dabbelt.com \
--cc=pjw@kernel.org \
--cc=samuel.holland@sifive.com \
--cc=thecharlesjenkins@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox