mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: Mark Brown <broonie@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>,
	 Will Deacon <will@kernel.org>, Jonathan Corbet <corbet@lwn.net>
Cc: Mark Rutland <mark.rutland@arm.com>,
	 linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
	 linux-kernel@vger.kernel.org, Mark Brown <broonie@kernel.org>
Subject: [PATCH] arm64/sme: Drop inaccurate documentation of streaming mode switches
Date: Wed, 23 Jul 2025 13:27:45 +0100	[thread overview]
Message-ID: <20250723-arm64-sme-mode-switch-doc-v1-1-702bb484b4f4@kernel.org> (raw)

The SME ABI documentation contains an inaccurate description of the
architectural streaming mode entry/exit behaviour, just remove it since
this is better documented by the architecture or with the rest of the
documentation for the specific software interfaces concerned.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
The rest of the documentation needs more thorough review, but it seems
wise to remove the incorrect statement to avoid confusion.
---
 Documentation/arch/arm64/sme.rst | 14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

diff --git a/Documentation/arch/arm64/sme.rst b/Documentation/arch/arm64/sme.rst
index 4cb38330e704..583f2ee9cb97 100644
--- a/Documentation/arch/arm64/sme.rst
+++ b/Documentation/arch/arm64/sme.rst
@@ -81,17 +81,7 @@ The ZA matrix is square with each side having as many bytes as a streaming
 mode SVE vector.
 
 
-3.  Sharing of streaming and non-streaming mode SVE state
----------------------------------------------------------
-
-It is implementation defined which if any parts of the SVE state are shared
-between streaming and non-streaming modes.  When switching between modes
-via software interfaces such as ptrace if no register content is provided as
-part of switching no state will be assumed to be shared and everything will
-be zeroed.
-
-
-4.  System call behaviour
+3.  System call behaviour
 -------------------------
 
 * On syscall PSTATE.ZA is preserved, if PSTATE.ZA==1 then the contents of the
@@ -112,7 +102,7 @@ be zeroed.
   exceptions for execve() described in section 6.
 
 
-5.  Signal handling
+4.  Signal handling
 -------------------
 
 * Signal handlers are invoked with PSTATE.SM=0, PSTATE.ZA=0, and TPIDR2_EL0=0.

---
base-commit: 86731a2a651e58953fc949573895f2fa6d456841
change-id: 20250722-arm64-sme-mode-switch-doc-8e132434b4ed

Best regards,
--  
Mark Brown <broonie@kernel.org>


             reply	other threads:[~2025-07-23 12:38 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-23 12:27 Mark Brown [this message]
2025-09-08 15:55 ` Will Deacon

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=20250723-arm64-sme-mode-switch-doc-v1-1-702bb484b4f4@kernel.org \
    --to=broonie@kernel.org \
    --cc=catalin.marinas@arm.com \
    --cc=corbet@lwn.net \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mark.rutland@arm.com \
    --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

all inboxes | Powered by JetHome®