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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 C9CB3C433E4 for ; Tue, 21 Jul 2020 16:14:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9C7EE2073A for ; Tue, 21 Jul 2020 16:14:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="BBE+e/Sn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730192AbgGUQOV (ORCPT ); Tue, 21 Jul 2020 12:14:21 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:49654 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726890AbgGUQOV (ORCPT ); Tue, 21 Jul 2020 12:14:21 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595348059; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=nU4GN8DzMVkB2B4BGU+FEKLwNEwIFvzsJZa/gMO7RWg=; b=BBE+e/SnE5P0z2sUKspvAVz9JOWx/TjVv9XhoKPJlaywi8xAwO8dwJ9ss9Oiy1ay2pJmDi /S3VqRloXdDvjnlndgK/llcV9e20pS6k/Ri6ykyatvsDnCT42jjyYoWcQJlY78tLn3N0oO X6EXjLFZO4b2oLcA7qq+zX4dhxwO7gY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-223-xGPIJL10Pvahp9if4m2pyA-1; Tue, 21 Jul 2020 12:14:17 -0400 X-MC-Unique: xGPIJL10Pvahp9if4m2pyA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2EFBD800469; Tue, 21 Jul 2020 16:14:16 +0000 (UTC) Received: from jlaw-desktop.redhat.com (ovpn-114-255.rdu2.redhat.com [10.10.114.255]) by smtp.corp.redhat.com (Postfix) with ESMTP id D18958730C; Tue, 21 Jul 2020 16:14:15 +0000 (UTC) From: Joe Lawrence To: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 0/2] livepatch: Add compiler optimization disclaimer/docs Date: Tue, 21 Jul 2020 12:14:05 -0400 Message-Id: <20200721161407.26806-1-joe.lawrence@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Sender: live-patching-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org In light of [PATCH] Revert "kbuild: use -flive-patching when CONFIG_LIVEPATCH is enabled" [1], we should add some loud disclaimers and explanation of the impact compiler optimizations have on livepatching. The first commit provides detailed explanations and examples. The list was taken mostly from Miroslav's LPC talk a few years back. This is a bit rough, so corrections and additional suggestions welcome. Expanding upon the source-based patching approach would be helpful, too. The second commit adds a small README.rst file in the livepatch samples directory pointing the reader to the doc introduced in the first commit. I didn't touch the livepatch kselftests yet as I'm still unsure about how to best account for IPA here. We could add the same README.rst disclaimer here, too, but perhaps we have a chance to do something more. Possibilities range from checking for renamed functions as part of their build, or the selftest scripts, or even adding something to the kernel API. I think we'll have a better idea after reviewing the compiler considerations doc. [1] https://lore.kernel.org/lkml/696262e997359666afa053fe7d1a9fb2bb373964.1595010490.git.jpoimboe@redhat.com/ Joe Lawrence (2): docs/livepatch: Add new compiler considerations doc samples/livepatch: Add README.rst disclaimer .../livepatch/compiler-considerations.rst | 220 ++++++++++++++++++ Documentation/livepatch/index.rst | 1 + Documentation/livepatch/livepatch.rst | 7 + samples/livepatch/README.rst | 15 ++ 4 files changed, 243 insertions(+) create mode 100644 Documentation/livepatch/compiler-considerations.rst create mode 100644 samples/livepatch/README.rst -- 2.21.3