Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757461Ab0BDEz0 (ORCPT ); Wed, 3 Feb 2010 23:55:26 -0500 Received: from mx1.redhat.com ([209.132.183.28]:23639 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757271Ab0BDEzY (ORCPT ); Wed, 3 Feb 2010 23:55:24 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit From: Roland McGrath To: "Lu, Hongjiu" X-Fcc: ~/Mail/linus Cc: "Siddha, Suresh B" , Oleg Nesterov , "H. Peter Anvin" , Ingo Molnar , Thomas Gleixner , LKML , "Lachner, Peter" Subject: RE: [patch] x86: ptrace and core-dump extensions for xstate In-Reply-To: Lu, Hongjiu's message of Wednesday, 3 February 2010 18:22:53 -0800 <8EA2C2C4116BF44AB370468FBF85A7770123AAB303@orsmsx504.amr.corp.intel.com> References: <1265076025.2802.194.camel@sbs-t61.sc.intel.com> <20100203230817.E6529AA@magilla.sf.frob.com> <8EA2C2C4116BF44AB370468FBF85A7770123AAB0AE@orsmsx504.amr.corp.intel.com> <20100204020224.45379725@magilla.sf.frob.com> <8EA2C2C4116BF44AB370468FBF85A7770123AAB2E8@orsmsx504.amr.corp.intel.com> <20100204021659.AB348C880@magilla.sf.frob.com> <8EA2C2C4116BF44AB370468FBF85A7770123AAB303@orsmsx504.amr.corp.intel.com> Emacs: resistance is futile; you will be assimilated and byte-compiled. Message-Id: <20100204045458.5AA2F7290@magilla.sf.frob.com> Date: Wed, 3 Feb 2010 20:54:58 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1016 Lines: 23 > To support XSAVE, gdb needs to know XCR0 as well as XSTATE size. > We can get those info from kernel via system call or cpuid. I > prefer cpuid over system call. Suresh's patch puts this value in the xsave block, in what Suresh calls "sw_usable_bytes". See the asm/ptrace-abi.h comment in the patch you signed off on. How is that not sufficient? If it is indeed not sufficient to usefully interpret the xsave block, then how could an xsave block in a core dump file ever possibly be examined if it might not have been generated on the same system and kernel where the debugger is doing the examination? If the NT_X86_XSTATE note as implemented in Suresh's patch is indeed not entirely self-contained in this way, then NAK on that new note format. Thanks, Roland -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/