From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id 29D173857356 for ; Fri, 29 Apr 2022 07:10:02 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 29D173857356 Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-99-1TdUIQK-O0aOR9higyLMhg-1; Fri, 29 Apr 2022 03:10:00 -0400 X-MC-Unique: 1TdUIQK-O0aOR9higyLMhg-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 14D5A8E8CC7; Fri, 29 Apr 2022 07:09:59 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.39.193.187]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3D1E3463DF7; Fri, 29 Apr 2022 07:09:58 +0000 (UTC) From: Florian Weimer To: Fangrui Song Cc: libc-alpha@sourceware.org Subject: Re: [PATCH v3 2/2] Default to --with-default-link=no (bug 25812) References: <15c7f6e9afe2c2b9c51ebc6372682a39b0932712.1649691083.git.fweimer@redhat.com> <20220428072502.4rpxnlreq72sgv5x@google.com> <87zgk5bnxo.fsf@oldenburg.str.redhat.com> <20220429060041.n24pkmlujglkumer@google.com> Date: Fri, 29 Apr 2022 09:09:56 +0200 In-Reply-To: <20220429060041.n24pkmlujglkumer@google.com> (Fangrui Song's message of "Thu, 28 Apr 2022 23:00:41 -0700") Message-ID: <87h76c74cb.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.85 on 10.11.54.10 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-5.1 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_LOW, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 29 Apr 2022 07:10:03 -0000 * Fangrui Song: >>How does lld place sections without a linker script? Purely based on >>names? > > It entirely uses code to describe the built-in rules like gold, while > GNU ld uses an internal linker script plus built-in code. > (some rules cannot be described by the linker script language and needs > code anyway). How can we make sure that certain sections are covered by RELRO, and still get start/stop symbols for them? >>> Besides, the position of .hash in --with-default-link=no seems weird. >>> 71213dc2589554dc8f8061e9b04e80c55d098b6a (2006-09) moved it to the end >>> of the RO segment. >> >>I think it's odd that we have an old-style hash table at all. Do we >>really need it? All tools should have migrated by now. > > We can remove .hash for non-mips architectures. We need the support in glibc for most architectures in the dynamic linker, but we don't have to build glibc with the legacy hash tables. > (I am a bit sad .MIPS.xhash support went in, but thankfully it doesn't take > too much code. The translation table could be solved in a better way. I > suspect the whole thing is unnecessary with RELR.) Huh? Aren't they unrelated? Thanks, Florian