From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Martin Subject: Re: [PATCH v4 20/28] arm64/sve: Add prctl controls for userspace vector length management Date: Mon, 30 Oct 2017 16:17:22 +0000 Message-ID: <20171030161709.GJ19485@e103592.cambridge.arm.com> References: <1509101470-7881-1-git-send-email-Dave.Martin@arm.com> <1509101470-7881-21-git-send-email-Dave.Martin@arm.com> <87r2toiikt.fsf@linaro.org> <20171028160506.GI19485@e103592.cambridge.arm.com> <87fua07gyq.fsf@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 55E2B49D13 for ; Mon, 30 Oct 2017 12:15:55 -0400 (EDT) Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id wqOavK0xeRnF for ; Mon, 30 Oct 2017 12:15:54 -0400 (EDT) Received: from foss.arm.com (foss.arm.com [217.140.101.70]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 1E33F49D09 for ; Mon, 30 Oct 2017 12:15:54 -0400 (EDT) Content-Disposition: inline In-Reply-To: <87fua07gyq.fsf@linaro.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu To: Alex =?iso-8859-1?Q?Benn=E9e?= Cc: linux-arch@vger.kernel.org, Okamoto Takayuki , libc-alpha@sourceware.org, Ard Biesheuvel , Szabolcs Nagy , Catalin Marinas , Will Deacon , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org List-Id: kvmarm@lists.cs.columbia.edu On Mon, Oct 30, 2017 at 04:12:13PM +0000, Alex Benn=E9e wrote: > = > Dave Martin writes: > = > > On Fri, Oct 27, 2017 at 06:52:50PM +0100, Alex Benn=E9e wrote: > >> > >> Dave Martin writes: > >> > >> > This patch adds two arm64-specific prctls, to permit userspace to > >> > control its vector length: > >> > > >> > * PR_SVE_SET_VL: set the thread's SVE vector length and vector > >> > length inheritance mode. > >> > > >> > * PR_SVE_GET_VL: get the same information. > >> > > >> > Although these prctls resemble instruction set features in the SVE > >> > architecture, they provide additional control: the vector length > >> > inheritance mode is Linux-specific and nothing to do with the > >> > architecture, and the architecture does not permit EL0 to set its > >> > own vector length directly. Both can be used in portable tools > >> > without requiring the use of SVE instructions. > >> > > >> > Signed-off-by: Dave Martin > >> > Reviewed-by: Catalin Marinas > >> > Cc: Alex Benn=E9e > >> > >> FYI there is a minor conflict applying this on current master. > > > > There are some trivial conflicts with one or two patches that already > > went into arm64/for-next/core, so I based on that for this posting, not > > torvalds/master. > > > > There's a note in the cover letter giving the precise commit I based > > on, though the branch doesn't seem to have moved yet since I posted. > = > Ahh probably those. It was only a few header file shuffles. I was > rushing to apply before my flight back I failed to note the change in > base commit. > = > > > > Otherwise, I don't see any conflict -- can you give details? > = > Only that #endif _ASM_ had been dropped from the header file. The #ifndef __ASSEMBLY__ ... #endif is added by another in-flight patch, so it depends on whether that patch (from arm64/for-next/core) is already applied. Cheers ---Dave