From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_MUTT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 05A74C31E4B for ; Fri, 14 Jun 2019 14:22:46 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D21D420866 for ; Fri, 14 Jun 2019 14:22:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="P/pRHcdW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D21D420866 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=/iVmkSM6ZGG1bm0ovWc7NtsxLx+gibTTg1rw1so8Rm0=; b=P/pRHcdWe605Gz Fu1o2Pe8JxH/tTYFsXVcwJKuwGcsCkUhksvajceeGrVTuDUhqDtfjjd9sE3Zn331EFP5veaOkN9fl Scbc8rmo7GSc+id85DInREM5hPBA8NVyh2NN0dRyCRFVlkpp1uubxgPg09E05enHwSq4jtQNo3dQa U8MlSAqqEGhO4IPzoz63jYH4DtwyiPFNQTOFAKxpHt5y8Ne9i5srNz4s3HCk1vtGqb/M63SCAUYWb e7bvUC/m/lS7slxjJLK8gFhFKZvtkVgjr7u30tBg4iJBZKUVnCuy4SupyxP3uBpT2uRwgx0u0db2u eyGAILLDrNfGvhADZHxg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hbn6J-0003AU-QJ; Fri, 14 Jun 2019 14:22:43 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hbn6H-0003A3-2U for linux-arm-kernel@lists.infradead.org; Fri, 14 Jun 2019 14:22:42 +0000 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 0FA17344; Fri, 14 Jun 2019 07:22:40 -0700 (PDT) Received: from fuggles.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8BF923F246; Fri, 14 Jun 2019 07:22:38 -0700 (PDT) Date: Fri, 14 Jun 2019 15:22:31 +0100 From: Will Deacon To: Anisse Astier Subject: Re: [PATCH] arm64/sve: should not depend on Message-ID: <20190614142231.GA29231@fuggles.cambridge.arm.com> References: <20190613163801.21949-1-aastier@freebox.fr> <20190613171432.GA2790@e103592.cambridge.arm.com> <20190614112222.GA47082@anisse-station> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190614112222.GA47082@anisse-station> User-Agent: Mutt/1.11.1+86 (6f28e57d73f2) () X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190614_072241_160755_D12A7FAD X-CRM114-Status: GOOD ( 20.09 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Catalin Marinas , Rich Felker , linux-kernel@vger.kernel.org, Kristina Martsenko , "Dmitry V . Levin" , Ricardo Salveti , Richard Henderson , Dave Martin , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Anisse, Dave, On Fri, Jun 14, 2019 at 01:22:22PM +0200, Anisse Astier wrote: > On Thu, Jun 13, 2019 at 06:14:44PM +0100, Dave Martin wrote: > > On Thu, Jun 13, 2019 at 06:38:01PM +0200, Anisse Astier wrote: > > > -#define SVE_PT_VL_INHERIT (PR_SVE_VL_INHERIT >> 16) > > > -#define SVE_PT_VL_ONEXEC (PR_SVE_SET_VL_ONEXEC >> 16) > > > +#define SVE_PT_VL_INHERIT (1 << 1) /* PR_SVE_VL_INHERIT */ > > > +#define SVE_PT_VL_ONEXEC (1 << 2) /* PR_SVE_SET_VL_ONEXEC */ > > > > Makes sense, but... > > > > Since sve_context.h was already introduced to solve a closely related > > problem, I wonder whether we can provide shadow definitions there, > > similarly to way the arm64/include/uapi/asm/ptrace.h definitions are > > derived. Although it's a slight abuse of that header, I think that > > would be my preferred approach. > > Yes I saw this, and I considered doing something similar. But, those > defines are in uapi/linux/prctl.h, which does not include any asm/*.h > header. This would have then required adding a full infrastructure for > asm/prctl.h (that could then include sve_context.h for example), which > does not exist yet, instead of copying these two values. x86 appears to have an asm/prctl.h implementation, but it's not included by anybody so I guess that doesn't really help us here. > Since this is part of the kernel-userspace ABI, I don't see this values > changing anytime soon, which is why I thought copying them shouldn't be > a big issue. Certainly not a big issue, just that the harder we make this to change the better. > A simple solution would be to to include sve_context.h or a third > header, maybe linux/prctl_arm64_sve.h (with only these two/five > defines), in linux/prctl.h, and reuse it in uapi/asm/ptrace.h; but this > would break the self-contained nature of linux/prctl.h. > > > > Otherwise, at least make the required relationship between ptrace.h and > > prctl.h constants a bit more obvious, say, > > > > #define SVE_PT_VL_INHERIT ((1 << 17) /* PR_SVE_SET_VL_INHERIT */ >> 16) > > This one is much simpler and closer to what I had in mind with this > patch. > > Will, what do you think of this second approach Dave proposed ? Duplication is grotty, but it does the job so I'm ok with it. I don't have any better ideas. Thanks, Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel