Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932811Ab2HQHGU (ORCPT ); Fri, 17 Aug 2012 03:06:20 -0400 Received: from moutng.kundenserver.de ([212.227.126.171]:53342 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750792Ab2HQHGR (ORCPT ); Fri, 17 Aug 2012 03:06:17 -0400 From: Arnd Bergmann To: Will Deacon Subject: Re: [PATCH v2 23/31] arm64: Debugging support Date: Fri, 17 Aug 2012 07:06:07 +0000 User-Agent: KMail/1.12.2 (Linux/3.5.0; KDE/4.3.2; x86_64; ; ) Cc: Catalin Marinas , "linux-arch@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , ulrich.weigand@linaro.org References: <1344966752-16102-1-git-send-email-catalin.marinas@arm.com> <20120816104748.GI31784@mudshark.cambridge.arm.com> <201208161249.35008.arnd@arndb.de> In-Reply-To: <201208161249.35008.arnd@arndb.de> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201208170706.07821.arnd@arndb.de> X-Provags-ID: V02:K0:x/xYMEAbgldRiVzz2rPDdkWkABTMXy4liIO5QNoCdgZ W/bQwOm6Ro3+W/0vVsNoqguUaGPhGNwQWGM3KujXXn0Q0+a6ve L/OYdbntq7vJbIGAstZ/oyfC/5XwlNltB/xehVb1nSNAlfmmC4 s+zvzSauY/0kA0Rzh7l459wO0RV5kDbCiOvNrPiDKuoPLB+tWM mYq3jpkhnjDjRaAYREk8gnvwc5/ra5+2GAG+U1LRxG4AiO+8la viYsEA9WBmWwZzvcN7Ft6qC3AHsz7NGjGqF0T3zyfdL2naseaw 1it8R1LbhvecUU9xdykFnjxsu/ZP1cUccU3tDbDSZJnAyPJ7Vr 4qvNZbNG8XMtg3rkuD5k= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2802 Lines: 69 On Thursday 16 August 2012, Arnd Bergmann wrote: > On Thursday 16 August 2012, Will Deacon wrote: > > On Wed, Aug 15, 2012 at 04:07:36PM +0100, Arnd Bergmann wrote: > > > On Tuesday 14 August 2012, Catalin Marinas wrote: > > > > From what I can tell, there is no support for 32 bit processes debugging > > > 64 bit ones. Is that something you plan to add in the future, or do you > > > consider that out of scope? In either case, a comment would be helpful. > > > > That can't really work because the debugger won't be able to manipulate > > child pointers properly without us adding a new ptrace interface (and then, > > I still wonder about how feasible it really is). I can add a comment. > > You can already have a 32 bit gdb that is able to do remote debugging of > 64 bit processes using a gdb server process. I guess it wouldn't be > too strange to have a ptrace extension to allow the native case as well. > I agree it's not a high priority. > > > > > +long arch_ptrace(struct task_struct *child, long request, > > > > + unsigned long addr, unsigned long data) > > > > +{ > > > > + int ret; > > > > + unsigned long *datap = (unsigned long __user *)data; > > > > + > > > > + switch (request) { > > > > + case PTRACE_GET_THREAD_AREA: > > > > + ret = put_user(child->thread.tp_value, datap); > > > > + break; > > > > + > > > > +#ifdef CONFIG_HAVE_HW_BREAKPOINT > > > > + case PTRACE_GETHBPREGS: > > > > + ret = ptrace_gethbpregs(child, addr, datap); > > > > + break; > > > > + > > > > + case PTRACE_SETHBPREGS: > > > > + ret = ptrace_sethbpregs(child, addr, datap); > > > > + break; > > > > +#endif > > > > + > > > > + default: > > > > + ret = ptrace_request(child, request, addr, data); > > > > + break; > > > > + } > > > > + > > > > + return ret; > > > > +} > > > > > > Is there a reaons why these are not regsets but have their own ptrace > > > commands? I believe new architectures should generally not add ptrace > > > commands any more. > > > > I could probably add some regset wrappers about the hbp accessors (which we > > have to keep for the compat ptrace interface). I'll have a think as it might > > even make sense to have different regsets for breakpoints and watchpoints. > > > > As for the the tls, is it worth having a regset with only one register? > > Better ask the gdb folks. I'm adding Uli to Cc, maybe he has some insight. Sorry for the dumb question, but why do you even need PTRACE_GET_THREAD_AREA for 64 bit tasks? I thought the thread pointer is a GPR, or is this just for compat tasks? Arnd -- 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/