Received: by 2002:a05:6358:1087:b0:cb:c9d3:cd90 with SMTP id j7csp7435189rwi; Mon, 24 Oct 2022 14:45:30 -0700 (PDT) X-Google-Smtp-Source: AMsMyM7LDaqofMGemqtWuxGQ0cU77T7lHNp/63yGyFNNq3B9PrgSYJAxvLIJ2T3D8S/PtCEL2eps X-Received: by 2002:a17:903:32cf:b0:186:b718:8156 with SMTP id i15-20020a17090332cf00b00186b7188156mr3491705plr.135.1666647929999; Mon, 24 Oct 2022 14:45:29 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1666647929; cv=none; d=google.com; s=arc-20160816; b=DPjQJcMPKyaJrhQgSPVdu8uQYnf3B3L5dSZh1YyUbW6XAO/fh72u4F0736DDKVUhor Rc+usP6IXXPviaxOzBfz5HdjOJtiWbivG/w1OXeSqeIUCy0bYkde9c+GZUcHENEVuUc6 SrJCic0FH4Pup8CZjm5jdSGpN9ioKcTJ832tMLUU3QDkl8hGaJHV/C1R3YFo+MLWtaxQ /7yzuhJIKsE5IKIEJITyixW/ghnxl9BHN6Xjukot1TF7zfCLjCIgtsUncNtwlHAcB1ey ZD/89QWMB/RpZWrn14cCpjGGHta10MMdx/iFRuQhkpQFQN6QVaRGvvhXISwsGSHS0ln1 tvQA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:message-id:references :in-reply-to:subject:cc:to:from:date:mime-version; bh=EniI4Dgygnk/l6DQ6SNvHkLTD01UOmHBGP6aUtH88Pw=; b=VBie8A22pnJOrAuMUN5pemDc5b2d9B4bN9632yQi+LHEDOeuFl+KFyz/+pB5jxAtN7 tY3KMJ475cSkS0W4s5rO9D16hl22P4b8n9VZMqqZaZOaqMyakZOhz7irq1lpa1Y9pHkG KqAxezStVAtBUZZdZiyn7OWHzTKhrlKr1ZE2tHwv/5B4hnSjWH0OA5pFYb+qLor0FGaA k/bWZc28eDZmOs20wLuIVhtfeYP6CNDZIPBjgFHdv79YKEUeudomuKCvORwqkjWnCbS3 SAxN+I2ezn/ajqlTqZ0ACOF9PQmlKAa8wS5bUaRdXKiExXOHyZNEy8jvVREj/jV2LnWP 8RUw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id f15-20020a170902ce8f00b001853a1fddecsi762993plg.403.2022.10.24.14.45.17; Mon, 24 Oct 2022 14:45:29 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234213AbiJXU2Z (ORCPT + 99 others); Mon, 24 Oct 2022 16:28:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39762 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231709AbiJXU10 (ORCPT ); Mon, 24 Oct 2022 16:27:26 -0400 Received: from relay5-d.mail.gandi.net (relay5-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::225]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C6F6F13C1FA for ; Mon, 24 Oct 2022 11:40:16 -0700 (PDT) Received: (Authenticated sender: joao@overdrivepizza.com) by mail.gandi.net (Postfix) with ESMTPA id ACDD81C0008; Mon, 24 Oct 2022 18:38:16 +0000 (UTC) MIME-Version: 1.0 Date: Mon, 24 Oct 2022 11:38:16 -0700 From: Joao Moreira To: Sami Tolvanen Cc: Peter Zijlstra , Josh Poimboeuf , x86@kernel.org, Kees Cook , linux-kernel@vger.kernel.org, Mark Rutland , Josh Poimboeuf Subject: Re: [PATCH] x86/ibt: Implement FineIBT In-Reply-To: References: <20221021230859.gysp5v3yzfqz4xgb@treble> Message-ID: X-Sender: joao@overdrivepizza.com Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_LOW, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Yes, the compiler patch is already in, but if the cfi/kcfi confusion > is a big concern, it's still possible to rename the symbol before > Clang 16 is released. However, I thought we picked the __cfi prefix > earlier to make things less confusing with FineIBT? Joao, are you > still planning on adding FineIBT to Clang as well? Not only with FineIBT, but also with CFG, ClangCFI and any other scheme that does CFI. IIRC, my concern was regarding some functions/structures that could be easily re-used in both (or many) schemes (such as setting the hashes for a specific call or something) being named to one specifically. But yeah, I didn't think at the time that there would be a different collision with Dwarf stuff. I still think that having a generic prefix is better, but I agree that the collision with dwarf is bad. Maybe we use something generic enough that doesn't collide, Idk, "cflow" or something like that (naming is hard). As for FineIBT within clang, that is still undecided. I'm waiting for peterz's patches to get in first, so then I can raise the discussion if it is worthy compiling the kernel directly with FineIBT. Also, on the user-space side, I'm waiting for IBT support to get in to then get back there and see if I can make it feasible. So the answer right now is really that it depends. Tks, Joao