Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753802Ab0BRSOF (ORCPT ); Thu, 18 Feb 2010 13:14:05 -0500 Received: from mail-ew0-f228.google.com ([209.85.219.228]:51288 "EHLO mail-ew0-f228.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753616Ab0BRSOB (ORCPT ); Thu, 18 Feb 2010 13:14:01 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=lPmXEI1F1lFTK+gUJMO1r+qScNDiRaJKaNhgG4nGiC/a18dsgHfsa15l08qdA/c604 fJrkjl+ZufpiYuJH4SmG9ErIC9mKb+dLk2a5FpkpezQeA96TwlT0G0/8FuiQkBhmVFNX xhkebwE98qroKVPiHHJrUEePtAR6L3d9GHZ24= Date: Thu, 18 Feb 2010 19:13:55 +0100 From: Frederic Weisbecker To: Masami Hiramatsu Cc: Mike Frysinger , Heiko Carstens , Ingo Molnar , LKML , Martin Schwidefsky , "David S . Miller" , Paul Mundt , Steven Rostedt Subject: Re: [PATCH 2/3] tracing/kprobes: Make Kconfig dependencies generic Message-ID: <20100218181352.GA5111@nowhere> References: <1266491616-6270-1-git-send-regression-fweisbec@gmail.com> <1266491616-6270-3-git-send-regression-fweisbec@gmail.com> <8bd0f97a1002180318g6ce70480x571d7d332239d68b@mail.gmail.com> <20100218120944.GA2406@osiris.boeblingen.de.ibm.com> <8bd0f97a1002180412x6cc4f280u5444f013c6e3b670@mail.gmail.com> <20100218123453.GA5136@nowhere> <20100218132521.GB2406@osiris.boeblingen.de.ibm.com> <8bd0f97a1002180601i60c5eaa4p7639091c5b617702@mail.gmail.com> <20100218145055.GB855@nowhere> <4B7D68AA.8060105@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4B7D68AA.8060105@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2512 Lines: 64 On Thu, Feb 18, 2010 at 11:19:54AM -0500, Masami Hiramatsu wrote: > Frederic Weisbecker wrote: > > On Thu, Feb 18, 2010 at 09:01:12AM -0500, Mike Frysinger wrote: > >>> --- a/arch/Kconfig > >>> +++ b/arch/Kconfig > >>> @@ -123,6 +123,10 @@ config USE_GENERIC_SMP_HELPERS > >>> > >>> config HAVE_REGS_AND_STACK_ACCESS_API > >>> bool > >>> + help > >>> + This symbol should be selected by an architecure if it supports > >>> + the API needed to access registers and stack entries from pt_regs. > >>> + For example the kprobes-based event tracer needs this API. > >> > >> a bit vague ... arent there headers/functions people could look at ? > >> perhaps you're talking about the regset functions (which is an API to > >> access registers in pt_regs) ? or you're talking about asm/syscall.h > >> (which is an API to access registers in pt_regs) ? > >> > >> i'm not asking to be a pain, i'm asking because i really havent a > >> clue. if i wanted to add support for this stuff to the Blackfin arch, > >> i wouldnt know where to start. even after reading this help i'd fall > >> back to grepping arch/x86/ and trying to divine a starting point from > >> there. > > > > > > If an arch support kprobes, it just needs to select > > HAVE_REGS_AND_STACK_ACCESS_API to figure out quickly what is missing, > > as gcc will barf every missing clues you need. > > These APIs are needed for kprobe-tracer on ftrace(kernel/trace/trace_kprobe.c), > which is just a consumer of kprobes (so depends on CONFIG_KPROBES). > > I mean, if you wanna figure out that, you have to select CONFIG_KPROBE_EVENT too :) > And then, gcc tries to compile trace_kprobe.c and quickly dumps error messages > what APIs are not found :) Yeah. > > For now it is stored is asm/ptrace.h, but that might be split in > > the future, especially as ptrace has initially nothing related to > > that. A documentation that deals with filenames or API enumerations > > tend to be incidentally async with API evolutions. > > yeah, now those APIs depend on pt_regs, so I put it in ptrace.h. > > Thank you, But anyway, if you prefer I can add a reference to ptrace.h in the config help. We just need to not forgot that if we move these functions later :) Thanks. -- 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/