From: Dave Hansen <dave.hansen@intel.com>
To: Florian Weimer <fweimer@redhat.com>,
libc-alpha@sourceware.org, linux-api@vger.kernel.org,
x86@kernel.org, linux-arch@vger.kernel.org
Cc: "H.J. Lu" <hjl.tools@gmail.com>
Subject: Re: x86 CPU features detection for applications (and AMX)
Date: Wed, 23 Jun 2021 08:32:09 -0700 [thread overview]
Message-ID: <e376bcb9-cd79-7665-5859-ae808dd286f1@intel.com> (raw)
In-Reply-To: <87tulo39ms.fsf@oldenburg.str.redhat.com>
On 6/23/21 8:04 AM, Florian Weimer wrote:
> https://www.gnu.org/software/libc/manual/html_node/X86.html
...
> Previously kernel developers have expressed dismay that we didn't
> coordinate the interface with them. This is why I want raise this now.
This looks basically like someone dumped a bunch of CPUID bit values and
exposed them to applications without considering whether applications
would ever need them. For instance, why would an app ever care about:
PKS – Protection keys for supervisor-mode pages.
And how could glibc ever give applications accurate information about
whether PKS "is supported by the operating system"? It just plain
doesn't know, or at least only knows from a really weak ABI like
/proc/cpuinfo.
It also doesn't seem to tell applications what they want which is, "can
I, the application, *use* this feature?"
> PS: Is it true that there is no public mailing list for Linux
> discussions specific to x86?
Yes. I've asked recently for something x86-related, but folks were to
concerned what I was asking for was too specific, which was more of a
brainstorming place to put x86-specific RFC's.
https://subspace.kernel.org/lists.linux.dev.html
next prev parent reply other threads:[~2021-06-23 15:33 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-23 15:04 x86 CPU features detection for applications (and AMX) Florian Weimer
2021-06-23 15:32 ` Dave Hansen [this message]
2021-07-08 6:05 ` Florian Weimer
2021-07-08 14:19 ` Dave Hansen
2021-07-08 14:31 ` Florian Weimer
2021-07-08 14:36 ` Dave Hansen
2021-07-08 14:41 ` Florian Weimer
2021-06-25 23:31 ` Thiago Macieira
2021-06-28 12:40 ` Enrico Weigelt, metux IT consult
2021-06-28 13:20 ` Peter Zijlstra
2021-06-30 12:50 ` Enrico Weigelt, metux IT consult
2021-06-30 15:36 ` Thiago Macieira
2021-07-01 7:35 ` Enrico Weigelt, metux IT consult
2021-06-28 15:08 ` Thiago Macieira
2021-06-28 15:27 ` Peter Zijlstra
2021-06-28 16:13 ` Thiago Macieira
2021-06-28 17:11 ` Peter Zijlstra
2021-06-28 17:23 ` Thiago Macieira
2021-06-28 19:08 ` Peter Zijlstra
2021-06-28 19:26 ` Thiago Macieira
2021-06-28 17:43 ` Peter Zijlstra
2021-06-28 19:05 ` Thiago Macieira
2021-06-30 14:32 ` Enrico Weigelt, metux IT consult
2021-06-30 14:34 ` Florian Weimer
2021-06-30 15:16 ` Enrico Weigelt, metux IT consult
2021-06-30 15:38 ` Florian Weimer
2021-07-01 8:08 ` Enrico Weigelt, metux IT consult
2021-07-01 8:21 ` Florian Weimer
2021-07-01 11:59 ` Enrico Weigelt, metux IT consult
2021-07-06 12:57 ` Florian Weimer
2021-06-30 15:29 ` Thiago Macieira
2021-07-01 11:57 ` Enrico Weigelt, metux IT consult
2021-07-08 7:08 ` Florian Weimer
2021-07-08 15:13 ` Thiago Macieira
2021-07-08 17:56 ` Mark Brown
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=e376bcb9-cd79-7665-5859-ae808dd286f1@intel.com \
--to=dave.hansen@intel.com \
--cc=fweimer@redhat.com \
--cc=hjl.tools@gmail.com \
--cc=libc-alpha@sourceware.org \
--cc=linux-api@vger.kernel.org \
--cc=linux-arch@vger.kernel.org \
--cc=x86@kernel.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.