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=-1.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 E0197C433E0 for ; Wed, 24 Jun 2020 17:13:54 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B117B20823 for ; Wed, 24 Jun 2020 17:13:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="yBnDlHtM"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="T4re3FJY" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B117B20823 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=alum.mit.edu Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:Date:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=lHXM1NXGwcPunauV531GTg3CM6jUt/1dU6dbn/+pNqM=; b=yBnDlHtMFkWwkHIZJpG2o6bvZ ixbRcyEe8Bye7KoW6oj/rH39oH/oSDGZfIOgGN3RhG3l0W7HQRuhZgAJOPY860B2F2WNdSvFdvy3k 3GO9H/zMRjU16ppsXXKWbcUlX2yiqupe8Vxx/jCluw965xUd2e9C8Egq92pCywlM+w8wahAiBRvvC fkBkVepckT2H7s4ENLePergsbQe0Pyo5ijpjZrTdjMhKRA1+bKWc3zRt2DRpX4qWf0UjASXddhqAi Se1YXADh7O9H4edzWCKWM29x3Sq1Ky79UcdmjA4t6h+gIjD9MDaO1uYvRrF7T3/yVM5rRdbY0fB56 K6gTrnKig==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jo8vr-0003Qa-UE; Wed, 24 Jun 2020 17:11:31 +0000 Received: from mail-qv1-xf44.google.com ([2607:f8b0:4864:20::f44]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jo8vp-0003Nd-FC for linux-arm-kernel@lists.infradead.org; Wed, 24 Jun 2020 17:11:30 +0000 Received: by mail-qv1-xf44.google.com with SMTP id u8so1369682qvj.12 for ; Wed, 24 Jun 2020 10:11:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:date:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=9YWMqwXjT5S6VAJIIaXravD3PBhiNi6VxmnHUwPk58o=; b=T4re3FJYILiDhz9PkEeru3WH+A8mIoGMSUfmqoPylClN1ucQbubgZwRaYB//PJ1fJa euX9ascn/HJ4kkLOgNypOY0irZn+1ylEhqG7wpZQDUmMqD++X0xBN8IvMGiotsKaJUYA vtraez/F8i7l/59H6Hv4bxYueuGKEO5/sbMgRy4TG5SyWgthFeJLkMSX06lS7H43qTEB jNBYNPvnx3B0yKQliUd7xQI9Gm/1cYM9hE/Q6SpRUDqZDF+IEs7llywzUVDfkbw6XclN VWaeMysZoB4WNQXs5/R8rYxiII0emUxuktYCxwj7DnB6YfSvuYwteQvU2/6dfvkCxWV+ 7M4g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:date:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=9YWMqwXjT5S6VAJIIaXravD3PBhiNi6VxmnHUwPk58o=; b=iBkrKkyeNZLCd5RkrmgBhzknzaB+vIsxHkGfLgJoSKyLlgaWKJ7pAmilZIhKXq3xuA vuh/KPObIEE2dgGyJXyVvtklueTB0RpqrU7+HZSJCSO+2OABy0iLnPPMkT2YbihehRiX z3EayhT8JT1n1JdSDmJ6BZWQx9fLUOpMyx9k3LLGUlIEoIQGMEapf6U9HVHG75IQSz4E tx0REkA/MD1z2HJ28g71s2V2TxE5cWzOWEIsosaUyMPx45Ptq9yRD3JWYpkKQmXF0xjL Bi3L4e2ND2dtk7dRUoD5L4xxbRspHFt4ircw8btkBxhXwUv2olQGJWbXVOtanKodoLx8 K+2g== X-Gm-Message-State: AOAM532itb/B8uwOpaXqPS5XpahAxJbcAisYofpGXUyZSt8fwm86nuiT P3oD5eU1ybEJnX4nWkJ1/Kw= X-Google-Smtp-Source: ABdhPJzzcFnkfc+tA2tOjjPS8V3pkJ6470qOFNUn3CmU7YZPddDvdZojC2NjkoNgT0+kvlBrLxUj/A== X-Received: by 2002:a0c:ed31:: with SMTP id u17mr30837447qvq.117.1593018683766; Wed, 24 Jun 2020 10:11:23 -0700 (PDT) Received: from rani.riverdale.lan ([2001:470:1f07:5f3::b55f]) by smtp.gmail.com with ESMTPSA id c2sm3746366qkl.58.2020.06.24.10.11.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 24 Jun 2020 10:11:23 -0700 (PDT) From: Arvind Sankar X-Google-Original-From: Arvind Sankar Date: Wed, 24 Jun 2020 13:11:21 -0400 To: Fangrui Song Subject: Re: [PATCH v3 2/9] vmlinux.lds.h: Add .symtab, .strtab, and .shstrtab to STABS_DEBUG Message-ID: <20200624171121.GA1377921@rani.riverdale.lan> References: <20200624014940.1204448-1-keescook@chromium.org> <20200624014940.1204448-3-keescook@chromium.org> <20200624153930.GA1337895@rani.riverdale.lan> <20200624161643.73x6navnwryckuit@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200624161643.73x6navnwryckuit@google.com> X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , linux-efi@vger.kernel.org, Catalin Marinas , Arvind Sankar , Will Deacon , Thomas Gleixner , linux-arch@vger.kernel.org, Masahiro Yamada , x86@kernel.org, Russell King , Ard Biesheuvel , clang-built-linux@googlegroups.com, Ingo Molnar , Borislav Petkov , Kees Cook , Arnd Bergmann , Nathan Chancellor , Peter Collingbourne , linux-arm-kernel@lists.infradead.org, Nick Desaulniers , linux-kernel@vger.kernel.org, James Morse Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Jun 24, 2020 at 09:16:43AM -0700, Fangrui Song wrote: > > On 2020-06-24, Arvind Sankar wrote: > >On Tue, Jun 23, 2020 at 06:49:33PM -0700, Kees Cook wrote: > >> When linking vmlinux with LLD, the synthetic sections .symtab, .strtab, > >> and .shstrtab are listed as orphaned. Add them to the STABS_DEBUG section > >> so there will be no warnings when --orphan-handling=warn is used more > >> widely. (They are added above comment as it is the more common > > > >Nit 1: is "after .comment" better than "above comment"? It's above in the > >sense of higher file offset, but it's below in readelf output. > > I mean this order:) > > .comment > .symtab > .shstrtab > .strtab > > This is the case in the absence of a linker script if at least one object file has .comment (mostly for GCC/clang version information) or the linker is LLD which adds a .comment > > >Nit 2: These aren't actually debugging sections, no? Is it better to add > >a new macro for it, and is there any plan to stop LLD from warning about > >them? > > https://reviews.llvm.org/D75149 "[ELF] --orphan-handling=: don't warn/error for unused synthesized sections" > described that .symtab .shstrtab .strtab are different in GNU ld. > Since many other GNU ld synthesized sections (.rela.dyn .plt ...) can be renamed or dropped > via output section descriptions, I don't understand why the 3 sections > can't be customized. So IIUC, lld will now warn about .rela.dyn etc only if they're non-empty? > > I created a feature request: https://sourceware.org/bugzilla/show_bug.cgi?id=26168 > (If this is supported, it is a consistent behavior to warn for orphan > .symtab/.strtab/.shstrtab > > There may be 50% chance that the maintainer decides that "LLD diverges" > I would disagree: there is no fundamental problems with .symtab/.strtab/.shstrtab which make them special in output section descriptions or orphan handling.) > .shstrtab is a little special in that it can't be discarded if the ELF file contains any sections at all. But yeah, there's no reason they can't be renamed or placed in a custom location in the file. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel