From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 10090 invoked by alias); 24 Sep 2012 12:23:05 -0000 Received: (qmail 10049 invoked by uid 22791); 24 Sep 2012 12:23:01 -0000 X-SWARE-Spam-Status: No, hits=-7.9 required=5.0 tests=AWL,BAYES_00,KHOP_RCVD_UNTRUST,KHOP_THREADED,RCVD_IN_DNSWL_HI,RCVD_IN_HOSTKARMA_W,RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mga03.intel.com (HELO mga03.intel.com) (143.182.124.21) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 24 Sep 2012 12:22:48 +0000 Received: from azsmga002.ch.intel.com ([10.2.17.35]) by azsmga101.ch.intel.com with ESMTP; 24 Sep 2012 05:22:46 -0700 X-ExtLoop1: 1 Received: from irsmsx101.ger.corp.intel.com ([163.33.3.153]) by AZSMGA002.ch.intel.com with ESMTP; 24 Sep 2012 05:22:45 -0700 Received: from irsmsx102.ger.corp.intel.com ([169.254.2.34]) by IRSMSX101.ger.corp.intel.com ([169.254.1.35]) with mapi id 14.01.0355.002; Mon, 24 Sep 2012 13:22:43 +0100 From: "Metzger, Markus T" To: Mark Kettenis CC: "gdb-patches@sourceware.org" , "markus.t.metzger@gmail.com" , "jan.kratochvil@redhat.com" , "palves@redhat.com" , "tromey@redhat.com" Subject: RE: [patch v3 16/16] btrace, x86: restrict to Atom Date: Mon, 24 Sep 2012 12:23:00 -0000 Message-ID: References: <1344949171-9545-1-git-send-email-markus.t.metzger@intel.com> <1344949171-9545-17-git-send-email-markus.t.metzger@intel.com> <201208141327.q7EDR7TC017727@glazunov.sibelius.xs4all.nl> In-Reply-To: Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2012-09/txt/msg00498.txt.bz2 Ping. > -----Original Message----- > From: Metzger, Markus T > Sent: Tuesday, August 14, 2012 3:42 PM > To: Mark Kettenis > Cc: gdb-patches@sourceware.org; markus.t.metzger@gmail.com; jan.kratochvi= l@redhat.com; palves@redhat.com; > tromey@redhat.com > Subject: RE: [patch v3 16/16] btrace, x86: restrict to Atom > > > -----Original Message----- > > From: Mark Kettenis [mailto:mark.kettenis@xs4all.nl] > > Sent: Tuesday, August 14, 2012 3:27 PM > > Thanks for your feedback! > > > > > +int > > > +i386_linux_supports_btrace (void) > > > +{ > > > + unsigned int cpuid, model, family; > > > + > > > + if (!linux_supports_btrace ()) > > > + return 0; > > > + > > > + __asm__ __volatile__ ("movl $1, %%eax;" > > > + "cpuid;" > > > + : "=3Da" (cpuid) > > > + :: "%ebx", "%ecx", "%edx"); > > > + > > [...] > > > You can't have this function in a -tdep.c, since this file needs to be > > compilable everywhere (not just on i386/amd64). But even in a -nat.c > > file you shouldn't use inline assembly, since it isn't a standardized > > C feature. I can only guess why you want to restrict this feature to > > Atom only, but I suspect that the proper solution is to query the > > target whether branch tracing is supported. That means the -nat.c > > code should have code to query for support in the Linux kernel. > > I agree that it would be better to have this check done in the kernel. Th= e problem is that such a patch will take very long before > it becomes available in distributions. And even then, we would need to ha= ndle kernels without the patch, so we would need > something > similar to this in gdb, as well. > > I took the cpuid bits from gdb/go32-nat.c. I have not seen any compilatio= n guard around it. > > I thought that the i386-tdep files are meant to contain i386 specific cod= e, that's why I put the code there. Where would be the > right place to put such code? > > Thanks, > Markus. Intel GmbH Dornacher Strasse 1 85622 Feldkirchen/Muenchen, Deutschland Sitz der Gesellschaft: Feldkirchen bei Muenchen Geschaeftsfuehrer: Peter Gleissner, Christian Lamprechter, Hannes Schwadere= r, Douglas Lusk Registergericht: Muenchen HRB 47456 Ust.-IdNr./VAT Registration No.: DE129385895 Citibank Frankfurt a.M. (BLZ 502 109 00) 600119052