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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 441F9C2D0DB for ; Wed, 29 Jan 2020 18:00:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1CA8C20716 for ; Wed, 29 Jan 2020 18:00:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="BjrjbIA0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727339AbgA2SA1 (ORCPT ); Wed, 29 Jan 2020 13:00:27 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:46168 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726171AbgA2SAZ (ORCPT ); Wed, 29 Jan 2020 13:00:25 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1580320824; 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=Dou/fbuzKGR7jcBj/3ZEbLPg5ko9v9+/o69GRY+vmSg=; b=BjrjbIA05jeGWHDfS6PIb2W0vQHBWVhPfFIhTJkyaWrfw6q8zAxJK+VAmMtIzPq16rv7KP Fa03JdwZtlOJ7X4RMyEctxtaruQOZmRydbNZWTgUanu3xlg6xuS8qmb220D21FP3U582CL R8mN9swVZEkrFDVy4bsJiQL2A+1LRCE= 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-4-fHfgGT1jN0y6NT5KeM91QA-1; Wed, 29 Jan 2020 13:00:18 -0500 X-MC-Unique: fHfgGT1jN0y6NT5KeM91QA-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 9719D477; Wed, 29 Jan 2020 18:00:16 +0000 (UTC) Received: from treble (ovpn-120-83.rdu2.redhat.com [10.10.120.83]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CBB195DA7B; Wed, 29 Jan 2020 18:00:14 +0000 (UTC) Date: Wed, 29 Jan 2020 12:00:12 -0600 From: Josh Poimboeuf To: Borislav Petkov Cc: Linus Torvalds , "Luck, Tony" , Ingo Molnar , Linux Kernel Mailing List , Thomas Gleixner , Borislav Petkov , Peter Zijlstra , Andrew Morton Subject: Re: [GIT PULL] x86/asm changes for v5.6 Message-ID: <20200129180012.jmncqyb7x77gkzwq@treble> References: <20200128165906.GA67781@gmail.com> <3908561D78D1C84285E8C5FCA982C28F7F5517F9@ORSMSX114.amr.corp.intel.com> <20200128223110.GB6787@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200128223110.GB6787@zn.tnic> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 28, 2020 at 11:31:10PM +0100, Borislav Petkov wrote: > On Tue, Jan 28, 2020 at 01:04:19PM -0800, Linus Torvalds wrote: > > On Tue, Jan 28, 2020 at 12:41 PM Luck, Tony wrote: > > > > > > Is there still some easy way to get gdb to disassemble from /dev/kmem > > > to see what we ended up with after all the patching? > > > > Hmm. No, I think it's all gone. > > > > It _used_ to be easy to just do "objdump --disassemble /proc/kcore" as > > root, but I think we've broken that long ago. > > Either booting with "debug-alternative" on baremetal or starting a guest > and stopping it with gdb and examining the patched memory is what I've > been using to hack on the alternatives in past years. Guest won't help > you a whole lot with FSRM but you could "force it", for example. FWIW, I can still do 'objdump -d' and gdb on /proc/kcore just fine (though you have to give gdb addresses because no symbols). -- Josh