From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 123559 invoked by alias); 7 Mar 2019 15:26:32 -0000 Mailing-List: contact binutils-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: binutils-owner@sourceware.org Received: (qmail 123543 invoked by uid 89); 7 Mar 2019 15:26:32 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham version=3.3.1 spammy=acting, Das, H*f:sk:c0f3180, H*i:sk:c0f3180 X-HELO: mail-wr1-f50.google.com Received: from mail-wr1-f50.google.com (HELO mail-wr1-f50.google.com) (209.85.221.50) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Thu, 07 Mar 2019 15:26:30 +0000 Received: by mail-wr1-f50.google.com with SMTP id i12so17899939wrw.0 for ; Thu, 07 Mar 2019 07:26:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=J1EU5Hz+h9rGy7R9j8TBNMbK1tauKQQ8pmWzJXUN2hg=; b=reV8PwQpSzoCrBVu32a+rFN57Png6OVF/qm6UU8gwRy4CSWlB8Dq4vg9owbexc7vhd CyZyYiHRhGbEB18vgSVPNlSLsyKEOQRp+m+qBu5d0XDlXGrBQt58jpdZfxQtW9xE+ug0 DL4k0qmW3qlzgRO2oFVUItC2vLm3tH1/8FRxDrdge+9HSy/JJVSyJ4VUXa0w6Bw+gJwH p2MXmPPLtsQc59vIVXyZp2Hd7wZ6gaUu0W7HM2WRUVwxu9+Uz1Y5NPpO4IiqPv15EFWS ZE0uQTsCqwM2CYR5pl70GdFMPix35x1Deklph/McaqaHItKCklDy9lEeuMCEdgCUJ868 jF7g== MIME-Version: 1.0 References: <08762e41-1e80-a504-d840-f8715ea59a50@arm.com> <581bbc74-441c-8f39-c4d5-38475f12dfb6@redhat.com> In-Reply-To: From: Peter Smith Date: Thu, 07 Mar 2019 15:26:00 -0000 Message-ID: Subject: Re: [PATCH, BFD, LD, AArch64, 0/4] Add support for AArch64 BTI and PAC in the linker To: Sudakshina Das Cc: "nickc@redhat.com" , "binutils@sourceware.org" , nd , Richard Earnshaw , Ramana Radhakrishnan Content-Type: text/plain; charset="UTF-8" X-SW-Source: 2019-03/txt/msg00035.txt.bz2 On Thu, 7 Mar 2019 at 14:28, Sudakshina Das wrote: > > Hi Nick > > On 07/03/2019 12:37, Nick Clifton wrote: > > Hi Sudi, > > > > [This is me being kind :-) ...] > > Thank you :) > > > >> We introduce a new set of command line options for the linker in order > >> to support the correct PLTs > > > > Are you also planning on creating patches for GOLD and LLD to support > > these features ? If so, it would probably be best to submit them at > > the same time as the BFD linker patches. > > I am CC'ing Peter who would be better able to answer about LLD and GOLD. I've got LLD work on my backlog at the moment. It will likely need to be coordinated with support for Intel CET (https://reviews.llvm.org/D58102), which introduces .note.gnu.property to LLD. Gold is of a lower priority right now, at least for Linaro, with the most likely outcome that it will be worked on when a project needs it, most likely when this feature is present in platforms that people use gold to build applications with. > > The document does not appear to specify what the loader should do if > > there is more than one GNU_PROPERTY_AARCh64_FEATURE_1_AND note in an > > executable. (Which would be there if the executable had been linked > > by a linker that does not know how to merge multiple GNU_PROPERTY notes). > > > > Hmm I have not really considered that. I will get back to you soon on this. > My initial thought is that if there is more than one .note.gnu.property section in the executable then the static linker didn't understand the section and hence we can't assume it did any of the required actions like producing different PLT sections. Hence I think acting as if there were no .note.gnu.property sections present at all would be a sensible choice. Peter