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=-8.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 298B5C433DF for ; Wed, 24 Jun 2020 23:40:24 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 75C61206C3 for ; Wed, 24 Jun 2020 23:40:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="eJvh37nN" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 75C61206C3 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-19154-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 32077 invoked by uid 550); 24 Jun 2020 23:40:17 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Received: (qmail 32039 invoked from network); 24 Jun 2020 23:40:17 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=OXwCzf5B5Vnc4rPGARP7edsvVNysUhYzQGqjGFLfJUg=; b=eJvh37nNRJoXUBuIREWky64c/2Zy+QfsGiyybHo4/AY79kM2WK5DCWQ2SFWNIlhRqR uvyBfk+MP4VctCsNpVpZcmoQSq5Bq2w+lQM6xBkh25apGFZZlExegOU/Xa4ZzLv1+QGo 2SZwCYjmMFcvWre4jkB8JFSvGQLtaMZLbShuOQoeq/pW5jRL7ENSqIcZKBium29PAxHa SUKoF/TCC6EPkmXpV56a4eqzpU85/8BnY0vmWySOQ6P4JhiJF+3GTW6JN67+OxEwI6FO 083DgLg4vlRvZAYijlbkUJhYrikRhcAUh0cGmqJe8b/JYcwRofo02mXuHf66C14NJXzV SJRA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=OXwCzf5B5Vnc4rPGARP7edsvVNysUhYzQGqjGFLfJUg=; b=qd72PBO2JlJVlkz/3BxZoS1h91YgX6DDKPJCg8FVQdZ8+fURanr0qdWTKj50I942u4 LOkNVrRytilZQ8QXVYY7nkxda3rAqut4TQ5pdb3h8MY5QZCT9CnGlcM38/sCSVUCK95v IbDeuyGc0tpxM/LsyA7KYbnKO/qLpREb/imE6Vqra+/iCstCd4CwseabUomgEEG2KEv+ gb8NCBM7TBzAswmU5Pp9wFN8ventuRYbQG3c8wn4H0DvlbMyGBywuMQQHhleyMWXzKu+ ZhkJb6X2ZHTVh2Gtc3TRo+XlBp8bEf11uwzBc4wItzZFCh1QuE+6vMo2YGFHKn9FZ3ZH JzXg== X-Gm-Message-State: AOAM5322F1bjIyGBubkDYj18+2Qz5sJVG2gzt4OpejzzVbzQ8LbCUVax EhtoBySl4ngOwl+3F6ES/Udv9w== X-Google-Smtp-Source: ABdhPJzXlVXz0ute8/7RtpY4QOpyoQzqmeZeuFCeuHxJTgdZ5uUxN+EFgHwfWmPsVtpJN+LSHdwUaA== X-Received: by 2002:aa7:9289:: with SMTP id j9mr33592532pfa.124.1593042004835; Wed, 24 Jun 2020 16:40:04 -0700 (PDT) Date: Wed, 24 Jun 2020 16:39:59 -0700 From: Sami Tolvanen To: Nick Desaulniers Cc: Masahiro Yamada , Will Deacon , Greg Kroah-Hartman , "Paul E. McKenney" , Kees Cook , clang-built-linux , Kernel Hardening , linux-arch , Linux ARM , Linux Kbuild mailing list , LKML , linux-pci@vger.kernel.org, "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" Subject: Re: [PATCH 17/22] arm64: vdso: disable LTO Message-ID: <20200624233959.GB94769@google.com> References: <20200624203200.78870-1-samitolvanen@google.com> <20200624203200.78870-18-samitolvanen@google.com> <20200624215231.GC120457@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Wed, Jun 24, 2020 at 04:05:48PM -0700, Nick Desaulniers wrote: > On Wed, Jun 24, 2020 at 2:52 PM Sami Tolvanen wrote: > > > > On Wed, Jun 24, 2020 at 01:58:57PM -0700, 'Nick Desaulniers' via Clang Built Linux wrote: > > > On Wed, Jun 24, 2020 at 1:33 PM Sami Tolvanen wrote: > > > > > > > > Filter out CC_FLAGS_LTO for the vDSO. > > > > > > Just curious about this patch (and the following one for x86's vdso), > > > do you happen to recall specifically what the issues with the vdso's > > > are? > > > > I recall the compiler optimizing away functions at some point, but as > > LTO is not really needed in the vDSO, it's just easiest to disable it > > there. > > Sounds fishy; with extern linkage then I would think it's not safe to > eliminate functions. Probably unnecessary for the initial > implementation, and something we can follow up on, but always good to > have an answer to the inevitable question "why?" in the commit > message. Sure. I can test this again with the current toolchain to see if there are still problems. Sami