From: Mark Brown <broonie@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Jonathan Corbet <corbet@lwn.net>
Cc: Dave Martin <dave.martin@arm.com>,
linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, Mark Brown <broonie@kernel.org>,
Edmund Grimley-Evans <edmund.grimley-evans@arm.com>
Subject: [PATCH 3/4] arm64/fp: Clarify effect of setting an unsupported system VL
Date: Mon, 22 Jan 2024 20:41:53 +0000 [thread overview]
Message-ID: <20240122-arm64-sve-sme-doc-v1-3-3d492e45265b@kernel.org> (raw)
In-Reply-To: <20240122-arm64-sve-sme-doc-v1-0-3d492e45265b@kernel.org>
The documentation for system vector length configuration does not cover all
cases where unsupported values are written, tighten it up.
Reported-by: Edmund Grimley-Evans <edmund.grimley-evans@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
Documentation/arch/arm64/sme.rst | 5 ++---
Documentation/arch/arm64/sve.rst | 5 ++---
2 files changed, 4 insertions(+), 6 deletions(-)
diff --git a/Documentation/arch/arm64/sme.rst b/Documentation/arch/arm64/sme.rst
index 3133d0e91b48..ba0a5e5b2523 100644
--- a/Documentation/arch/arm64/sme.rst
+++ b/Documentation/arch/arm64/sme.rst
@@ -379,9 +379,8 @@ The regset data starts with struct user_za_header, containing:
/proc/sys/abi/sme_default_vector_length
Writing the text representation of an integer to this file sets the system
- default vector length to the specified value, unless the value is greater
- than the maximum vector length supported by the system in which case the
- default vector length is set to that maximum.
+ default vector length to the specified value rounded to a supported value
+ using the same rules as for setting vector length via prctl().
The result can be determined by reopening the file and reading its
contents.
diff --git a/Documentation/arch/arm64/sve.rst b/Documentation/arch/arm64/sve.rst
index b45a2da19bf1..b923727ff4b9 100644
--- a/Documentation/arch/arm64/sve.rst
+++ b/Documentation/arch/arm64/sve.rst
@@ -423,9 +423,8 @@ The regset data starts with struct user_sve_header, containing:
/proc/sys/abi/sve_default_vector_length
Writing the text representation of an integer to this file sets the system
- default vector length to the specified value, unless the value is greater
- than the maximum vector length supported by the system in which case the
- default vector length is set to that maximum.
+ default vector length to the specified value rounded to a supported value
+ using the same rules as for setting vector length via prctl().
The result can be determined by reopening the file and reading its
contents.
--
2.30.2
next prev parent reply other threads:[~2024-01-22 20:42 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-22 20:41 [PATCH 0/4] arm64/fp: Documentation cleanups and clarifications Mark Brown
2024-01-22 20:41 ` [PATCH 1/4] arm64/sve: Remove bitrotted comment about syscall behaviour Mark Brown
2024-01-23 15:44 ` Dave Martin
2024-01-23 17:31 ` Mark Brown
2024-01-23 17:54 ` Dave Martin
2024-01-23 18:11 ` Mark Brown
2024-01-24 14:04 ` Dave Martin
2024-01-22 20:41 ` [PATCH 2/4] arm64/sme: Fix cut'n'paste in ABI document Mark Brown
2024-01-22 20:41 ` Mark Brown [this message]
2024-01-23 15:49 ` [PATCH 3/4] arm64/fp: Clarify effect of setting an unsupported system VL Dave Martin
2024-01-23 18:42 ` Mark Brown
2024-01-24 14:09 ` Dave Martin
2024-01-22 20:41 ` [PATCH 4/4] arm64/sme: Remove spurious 'is' in SME documentation Mark Brown
2024-01-23 15:50 ` Dave Martin
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=20240122-arm64-sve-sme-doc-v1-3-3d492e45265b@kernel.org \
--to=broonie@kernel.org \
--cc=catalin.marinas@arm.com \
--cc=corbet@lwn.net \
--cc=dave.martin@arm.com \
--cc=edmund.grimley-evans@arm.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=will@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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).