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=-5.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 F3BDCC433E0 for ; Sat, 23 Jan 2021 02:28:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AECF623B26 for ; Sat, 23 Jan 2021 02:28:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726275AbhAWC1r (ORCPT ); Fri, 22 Jan 2021 21:27:47 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:55296 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726013AbhAWC1o (ORCPT ); Fri, 22 Jan 2021 21:27:44 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1611368778; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=jJX45dFL81O/CxuAJek1TRpHKAzDl0ox2asYfOyKPaQ=; b=eejmuTD9rZZkHl+LdDLjiQC9OCNTV8uTNv4t3dsAawA+aYhzWG9flV+3ITCGjTACD163yx S83DVAHYuErsErsXTcEPbgQLgAEYrZrqSj+j9stjlAaUfF4FgVVMGzfxAntRjzze5wjbvL 8WDqietqOfJcg4R7o9WuyQaOni1kcgw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-123-Ek-tnCOaM1Osdmp0eicttg-1; Fri, 22 Jan 2021 21:26:14 -0500 X-MC-Unique: Ek-tnCOaM1Osdmp0eicttg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2F3A9180A09D; Sat, 23 Jan 2021 02:26:12 +0000 (UTC) Received: from treble (ovpn-117-226.rdu2.redhat.com [10.10.117.226]) by smtp.corp.redhat.com (Postfix) with ESMTPS id EFA7D5DA33; Sat, 23 Jan 2021 02:26:10 +0000 (UTC) Date: Fri, 22 Jan 2021 20:26:09 -0600 From: Josh Poimboeuf To: Nick Desaulniers Cc: Sami Tolvanen , Sedat Dilek , X86 ML , LKML , Peter Zijlstra , Kees Cook , Clang-Built-Linux ML , Miroslav Benes , Fangrui Song , Peter Collingbourne Subject: Re: [PATCH v2 00/20] objtool: vmlinux.o and CLANG LTO support Message-ID: <20210123022609.n7xsj2a4potoijz7@treble> References: <20210122154158.lylubqugmcxehugg@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 22, 2021 at 05:32:43PM -0800, Nick Desaulniers wrote: > > In this specific case, find_func_by_offset returns NULL for > > .text..L.cfi.jumptable.43 at addend 0x8, because Clang doesn't emit > > jump table symbols for static functions: > > > > 0000000000000000 <__typeid__ZTSFjmiE_global_addr>: > > 0: e9 00 00 00 00 jmpq 5 <__typeid__ZTSFjmiE_global_addr+0x5> > > 1: R_X86_64_PLT32 io_serial_in-0x4 > > 5: cc int3 > > 6: cc int3 > > 7: cc int3 > > 8: e9 00 00 00 00 jmpq d <__typeid__ZTSFjmiE_global_addr+0xd> > > 9: R_X86_64_PLT32 mem32_serial_in-0x4 > > d: cc int3 > > e: cc int3 > > f: cc int3 > > > > Nick, do you remember if there were plans to change this? > > Do you have a link to any previous discussion to help jog my mind; I > don't really remember this one. > > Is it that `__typeid__ZTSFjmiE_global_addr` is the synthesized jump > table, and yet there is no `__typeid__ZTSFjmiE_global_addr` entry in > the symbol table? I think he means there's not a 'mem32_serial_in.cfi_jt' symbol at '__typeid__ZTSFjmiE_global_addr+8'. Probably more aggressive symbol pruning from the assembler. It's fine though. I just need to rewrite the CFI support a bit. But that can come later. For now I'll just drop the two CFI-related patches from this set so I can merge the others next week. -- Josh