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=-2.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 BF357C433FF for ; Thu, 1 Aug 2019 08:50:00 +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 935EF206A3 for ; Thu, 1 Aug 2019 08:50:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="WCBmY7Ar" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 935EF206A3 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:Date: Message-ID:From:References:To:Subject:Reply-To:Content-ID:Content-Description :Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=iGkqU9ezSPD90IjGlK1ucbYxfzzbocVehhGlNcdBlow=; b=WCBmY7ArDZWlly nG0gyxGLv7ZrU7nsNE+oNE+sgrRxJNKgvO5DOyo3GKssZBJxOJRzflXlrW7TJhSNaDLHdTqbyV0HG cniSutwjtr0/+SrEwQsR/3diW7aDfEXiyH1DrWLB8SOS11IpJTBFQJGmIzA3mbu3h7yDYjDz64x5R lkl93NTK77q7JS5ZGLQcsByEpUlbhQOwZceUV0vDgpE6EvTgDB66YGrw37+ZZieyHOK2D8F3TmVaf 1EGrYGPb1MTpd62UN5S3QM7WWW8e/L6p3d/cB6JdvSYd0E/7s+Pp7LHjOYHfeDgqetHVXgcwyeBvF L4obgqI584C1rSoK+Ujw==; 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 1ht6me-0008FR-AJ; Thu, 01 Aug 2019 08:50:00 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1ht6mb-0008F6-Qo for linux-arm-kernel@lists.infradead.org; Thu, 01 Aug 2019 08:49:59 +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 19CAD337; Thu, 1 Aug 2019 01:49:57 -0700 (PDT) Received: from [10.1.197.45] (e112298-lin.cambridge.arm.com [10.1.197.45]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3938A3F694; Thu, 1 Aug 2019 01:49:55 -0700 (PDT) Subject: Re: [PATCH v4.4 V2 25/43] arm64: Move BP hardening to check_and_switch_context To: Greg KH , Will Deacon References: <59b252cf-9cb7-128b-4887-c21a8b9b92a9@arm.com> <20190801050940.h65crfawrdifsrgg@vireshk-i7> <86354576-fc54-a8b7-4dc9-bc613d59fb17@arm.com> <20190801063544.ruw444isj5uojjdx@vireshk-i7> <20190801065700.GA17391@kroah.com> <20190801070541.hpmadulgp45txfem@vireshk-i7> <20190801073444.4n45h6kcbmejvzte@willie-the-truck> <20190801084354.GA1085@kroah.com> From: Julien Thierry Message-ID: Date: Thu, 1 Aug 2019 09:49:54 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190801084354.GA1085@kroah.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190801_014957_994742_632D8740 X-CRM114-Status: GOOD ( 15.03 ) 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 , Marc Zyngier , Viresh Kumar , Will Deacon , stable@vger.kernel.org, mark.brown@arm.com, linux-arm-kernel@lists.infradead.org, Catalin Marinas , Russell King , julien.thierry.kdev@gmail.com 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 On 01/08/2019 09:43, Greg KH wrote: > On Thu, Aug 01, 2019 at 08:34:45AM +0100, Will Deacon wrote: >> On Thu, Aug 01, 2019 at 12:35:41PM +0530, Viresh Kumar wrote: >>> On 01-08-19, 08:57, Greg KH wrote: >>>> On Thu, Aug 01, 2019 at 12:05:44PM +0530, Viresh Kumar wrote: >>>>> On 01-08-19, 07:30, Julien Thierry wrote: >>>>>> I must admit I am not familiar with backport/stable process enough. But >>>>>> personally I think the your suggestion seems more sensible than >>>>>> backporting 4 patches. >>>>>> >>>>>> Or you can maybe ignore patch 25 and say in patch 24 that among the >>>>>> changes made for the 4.4 codebase, the call arm64_apply_bp_hardening() >>>>>> was moved from post_ttbr_update_workaround as it doesn't exist and >>>>>> placed in check_and_switch_context() as it is its final destination. >>>>> >>>>> Done that and dropped the other two patches. >>>>> >>>>>> However, I really don't know what's the best way to proceed according to >>>>>> existing practices. So input from someone else would be welcome. >>>>> >>>>> Lets see if someone comes up and ask me to do something else :) >>>> >>>> Keeping the same patches that upstream has is almost always the better >>>> thing to do in the long-run. >>> >>> That would require two additional patches to be backported, 22 and 23 >>> from this series. From your suggestion it seems that keeping them is >>> better here ? >> >> Yes. Backporting individual patches as they appear upstream is definitely >> the preferred method for -stable. It makes the relationship to mainline >> crystal clear, as well as any dependencies between patches that have been >> backported. Everytime we tweak something unecessarily in a stable backport, >> it just creates the potential for confusion and additional conflicts in >> future backports, so it's best to follow the shape of upstream as closely as >> possible, even if it results in additional patches. >> >> So I wouldn't worry about total number of patches. I'd worry more about >> things like conflicts, deviation from mainline and overall testing coverage. > > That is exactly correct, thanks for saying it better than I could :) > Thanks, I'll try to keep those guidelines in mind for my future comments on backports. Cheers, -- Julien Thierry _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel