From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 3EE6960265; Tue, 23 Jan 2024 15:49:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706024974; cv=none; b=bCVp3TumgGstd0YuD+zrAyNVSTBrzaAZ6qX7TPSbBjB3VR3hASNKmsJ1JlqZ3D9a6QgRA+9B9+xvAepxgs9V9kntNQafVyF4g9EI40zDfCgKoLo5ks/cNDEfY2kvNA4tqnRRSKUjmrSX2fNQcLhXvDANR7qob1E+s6uTbW9W6OU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706024974; c=relaxed/simple; bh=AzbsMvmKAIX7RADh8WN6TnAlQ/vHfo/L7WFXSV5xX3U=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Hx0QVGPiD/ASAgj5xcduySzMxGUZCC6JY5ImlBWkAHi5lbQsybuXrqcTFC94U0BJIQtLjlrpWrfFdj6rIjiuH4P9ekJwtLuzR8YKWnH3YTshQlI5dxPtum6qrJS1vfE5RG7sl0XadKycPZgngIVucWoTOa1/nuJRMdOQxSmg8gs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CD0A41FB; Tue, 23 Jan 2024 07:50:15 -0800 (PST) Received: from e133380.arm.com (e133380.arm.com [10.1.197.58]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6E6C03F5A1; Tue, 23 Jan 2024 07:49:29 -0800 (PST) Date: Tue, 23 Jan 2024 15:49:27 +0000 From: Dave Martin To: Mark Brown Cc: Catalin Marinas , Will Deacon , Jonathan Corbet , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Edmund Grimley-Evans Subject: Re: [PATCH 3/4] arm64/fp: Clarify effect of setting an unsupported system VL Message-ID: References: <20240122-arm64-sve-sme-doc-v1-0-3d492e45265b@kernel.org> <20240122-arm64-sve-sme-doc-v1-3-3d492e45265b@kernel.org> 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=us-ascii Content-Disposition: inline In-Reply-To: <20240122-arm64-sve-sme-doc-v1-3-3d492e45265b@kernel.org> On Mon, Jan 22, 2024 at 08:41:53PM +0000, Mark Brown wrote: > 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 > --- > 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(). Do parallel changes need to be made in sve.rst? (There seems to be so much duplication and copy-paste between these files that I wonder whether it would make sense to merge them... but that's probably a separate discussion.) Nit: is it better to name the prctl here than just to say prctl()? That would be easier for the reader to cross-reference. > > 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(). Ditto. [...] Cheers ---Dave