From nobody Wed Dec 24 19:58:43 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 3886E12BEA2; Wed, 24 Jan 2024 18:12:51 +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=1706119972; cv=none; b=W6/2XUUuYk2U0gs8FAd7IqzjQcbHMc44tAoxK036+269CQ06HLdn1/u/+Y4PTreDPiayNjlmpB//xGq/tyXRFvd7OXpztXPGNsbWEnNa0W0pspJZpfMIB31H69vsg7aB0YwsdUmFfMdJVZ7SYYYZZHLtbJ7VSo0YejSD1jv0gQ4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706119972; c=relaxed/simple; bh=SZE/NEKa8x7WLFeaaJG3HC5W7JWmr0VNMdNibq7Cpz8=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=B0Nw8Nw6x/+KyYS5kAoS0uAJMumc92aWLoiXrWMM1uLJP7PvKWGW7t/MzJyoD4LM0CEO7F10bLjbinIqUF9bY3PqbHfoPI4MfsXTIorBFxyoUJq9EwwfGuOO4GxGJJmmHL0n+P64aztsD2iwx1/e6L/rgW34/DYwQVI/muVijQk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DhzBkrtP; 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="DhzBkrtP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 02A04C43390; Wed, 24 Jan 2024 18:12:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1706119971; bh=SZE/NEKa8x7WLFeaaJG3HC5W7JWmr0VNMdNibq7Cpz8=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=DhzBkrtPs6ZKDJAaSiEMKQASXyB3DKkTRbivSAWpMlE8hGwlWMonvwe+sLGYqZxZU rTt8F2caoXVnvtMiz8G2SQywSfF+WWN95zBQPcAWxgGxjBoUdAEARBG/2kkii1Ho1X cEhU/gmzwuG3nSPC75OHgZImBN4LPC941Gr69TjyA39vNH+RKwEEIgQztrMGfKKWA9 G9wfX85Zlgm69KeBPBeDtv+FcqsMWmfkzWfXzH3ag6wRseFZbeAnO82+Rs+PcJNdS+ tpUtToxWNiN04PfUlfRqDZJeEoBL1RZ38I5Zn4/U0It6JUnhItM9GAy56TzFgk/jPZ /M4X8O3dLtbiQ== From: Mark Brown Date: Wed, 24 Jan 2024 18:12:37 +0000 Subject: [PATCH v2 3/4] arm64/fp: Clarify effect of setting an unsupported system VL 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: <20240124-arm64-sve-sme-doc-v2-3-fe3964fb3c19@kernel.org> References: <20240124-arm64-sve-sme-doc-v2-0-fe3964fb3c19@kernel.org> In-Reply-To: <20240124-arm64-sve-sme-doc-v2-0-fe3964fb3c19@kernel.org> To: Catalin Marinas , Will Deacon , Jonathan Corbet Cc: Dave Martin , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Mark Brown , Edmund Grimley-Evans X-Mailer: b4 0.13-dev-a684c X-Developer-Signature: v=1; a=openpgp-sha256; l=2159; i=broonie@kernel.org; h=from:subject:message-id; bh=SZE/NEKa8x7WLFeaaJG3HC5W7JWmr0VNMdNibq7Cpz8=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBlsVMZuoJ837tq8yyiOk6QDDv0LqvP8sPwfC9POuaW cRNacMuJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZbFTGQAKCRAk1otyXVSH0IbeB/ 9uVCyeNQpECVM396Hnf/CcRMD/pftd849z37RwVfAGu2PVR32XoC7Xc5HL6+pAPSC1WzROF48vajD4 +SkqG6ViZPiC0StIEtsCiYUOcX1sgsld2OgweiWJkUERIm2n/8GlU5azPGxHEzO0TGsJZ46kyXSGU8 PMdNrMC4c9GE8py4j0yPwhckaFDnS1Ne5jq40+eLOuGuHxj201TcPX5FCyZwI9Y/rk8qOvE6hqAObq av1K7DAUNHaeRuOY8UL3iwuyBD/a/eTP9nhBs0yk1meLjenQ3gXh2jfBXCbe1Znz3PiOBLnjbXE8X6 QXbdSV9M392527bpXFNRh0v3E9o5BL X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB 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 Signed-off-by: Mark Brown Reviewed-by: Dave Martin --- 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/sm= e.rst index 3133d0e91b48..f4376c06f447 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, cont= aining: /proc/sys/abi/sme_default_vector_length =20 Writing the text representation of an integer to this file sets the sy= stem - default vector length to the specified value, unless the value is grea= ter - than the maximum vector length supported by the system in which case t= he - default vector length is set to that maximum. + default vector length to the specified value rounded to a supported va= lue + using the same rules as for setting vector length via PR_SME_SET_VL. =20 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/sv= e.rst index b45a2da19bf1..8d8837fc39ec 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, con= taining: /proc/sys/abi/sve_default_vector_length =20 Writing the text representation of an integer to this file sets the sy= stem - default vector length to the specified value, unless the value is grea= ter - than the maximum vector length supported by the system in which case t= he - default vector length is set to that maximum. + default vector length to the specified value rounded to a supported va= lue + using the same rules as for setting vector length via PR_SVE_SET_VL. =20 The result can be determined by reopening the file and reading its contents. --=20 2.30.2