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>
next 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
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