From nobody Mon Oct 6 08:27:59 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 54A6726C3BD; Wed, 23 Jul 2025 12:38:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753274324; cv=none; b=Obnm97g/iohfRe3FxRJPb1L/07l5hKGV1Zwa80ejxshfgF/+wdbcwxLF2a2VCmBdl7Fo6BEIiiPoHkuSZQAmBlsWjsswqkMQfU1xCpwz4TdGpbZppg/pOBY1GmlvvIkBucikl2u6orUWjuJOkgqAB+pqBAMQPJf/RaeLFcLQL/c= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753274324; c=relaxed/simple; bh=OrTb+KcHqT4ajdsH1ypK8FaKVkgJa8ksvVRgB8HRm9Q=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=fQ91SoOF2r1pSRvvvAtLAL/P62/WNObPc9h0ZAqAJiYLo59ioqaf3EOl6Fm4gWP6iIq9rIJcmX75yZ1DCCz2c81fC/P7GDgDOubJA/9M8BvzXpSTSnuOLZrc79xm393s3QLQbEBSMy16cZSwih6kDUl4pIpz2K8TcXgS/Ar9qlw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RDhmv4d0; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RDhmv4d0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5D940C4CEE7; Wed, 23 Jul 2025 12:38:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1753274322; bh=OrTb+KcHqT4ajdsH1ypK8FaKVkgJa8ksvVRgB8HRm9Q=; h=From:Date:Subject:To:Cc:From; b=RDhmv4d0mUWTFu/k6l+UgHLvejZEHBBcCvuOIo8nKodYeCvy+R8vxIiOVsm1q5JOQ UsrRTEdNNtnDr9n1eqkSUf95LHjki0r7NChsEJc37EiZPy3FZaXpOp1USxa78ZVWv0 tuyMocSaFBl7WcHl3c/07K9XCpnUq66Esftj/19hyYg68nLgz5Xp9QwZMsSCjS1E0N 5x0RUI3Igu7319Us20lfGHASKXT91o9pSK2yUANHXbKAU3KGRHreHXiuXbYKbbU2WU ErW0ksZ+wacNF9oO4SiESQeC7UcafWUVHrfIo/8BWzh4d9dAcYVlXHWEwqxu05EHoB QBF5TpoFQ+Wog== From: Mark Brown Date: Wed, 23 Jul 2025 13:27:45 +0100 Subject: [PATCH] arm64/sme: Drop inaccurate documentation of streaming mode switches Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250723-arm64-sme-mode-switch-doc-v1-1-702bb484b4f4@kernel.org> X-B4-Tracking: v=1; b=H4sIAEDVgGgC/x3MQQ6CMBBG4auQWTMJTIsar0JcYPsjsyg1HaMmh LvTsPwW721kKAqje7NRwVdN81rRtw2FZVpfYI3VJJ0M3VWEp5Iuni2BU45g++knLBxz4Bt6J97 5p0ek2r8LZv2f7/Gx7wfH5ah4awAAAA== X-Change-ID: 20250722-arm64-sme-mode-switch-doc-8e132434b4ed To: Catalin Marinas , Will Deacon , Jonathan Corbet Cc: Mark Rutland , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Mark Brown X-Mailer: b4 0.15-dev-cff91 X-Developer-Signature: v=1; a=openpgp-sha256; l=1936; i=broonie@kernel.org; h=from:subject:message-id; bh=OrTb+KcHqT4ajdsH1ypK8FaKVkgJa8ksvVRgB8HRm9Q=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBogNfQPuSRx5nolzVnWzO3f5C+iSWPt1ou4zVoV QuR7n/k3ZGJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCaIDX0AAKCRAk1otyXVSH 0MvbB/oDMKFjJJgkmKz5aDIP9D9olw3VGOkisOZtq2L19yAa9LIBaPWqfS+u9NiffrlmpSi2adO Ome5zhPsryc5XH/0b+eDJIcu/BaqhePrwNg2u0IlIwjm4Wn3YrtR3cN+HjuobeHawVeLM48T5jS J2GPCXLn2yG81L7/hWfPqXfIqyEqUTYq6EmojjpfL9OKelTZi9MDwI2Bil9NC1I/WwQ+3vOXXho wajoW9rC37ZFRdXv0bzPkeZ01YcPaqUH1gaJAt9yMwhHkeHnil5+omwXdskK809wqSe2SypOlzh YyUqU4VVrdPAXYbic0RXO4NhuMJ7tIPmfvqvq3NNQtAhZnT7 X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB 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 --- 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/sm= e.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 by= tes as a streaming mode SVE vector. =20 =20 -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 ------------------------- =20 * On syscall PSTATE.ZA is preserved, if PSTATE.ZA=3D=3D1 then the contents= of the @@ -112,7 +102,7 @@ be zeroed. exceptions for execve() described in section 6. =20 =20 -5. Signal handling +4. Signal handling ------------------- =20 * Signal handlers are invoked with PSTATE.SM=3D0, PSTATE.ZA=3D0, and TPIDR= 2_EL0=3D0. --- base-commit: 86731a2a651e58953fc949573895f2fa6d456841 change-id: 20250722-arm64-sme-mode-switch-doc-8e132434b4ed Best regards, -- =20 Mark Brown