Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758479Ab0BRPnL (ORCPT ); Thu, 18 Feb 2010 10:43:11 -0500 Received: from ey-out-2122.google.com ([74.125.78.26]:1756 "EHLO ey-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755932Ab0BRPnI (ORCPT ); Thu, 18 Feb 2010 10:43:08 -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:content-transfer-encoding :in-reply-to:user-agent; b=Xeyol9d4H8P/tR5m5HJzi/u9Nd6te30xuZ7fAu2jQFptQ282LdESapxU7QKEwTgazt FMIM3xgy1QIVp0BSzGj1a0mXbARC4j93J4T0TmgQ89A4ulO2ymvGhTUqcSzCvpFjlbTL iQk89Ww8qo1XweeETzEYaV4fWH/fwGHklLUzE= Date: Thu, 18 Feb 2010 16:43:02 +0100 From: Frederic Weisbecker To: Mike Frysinger Cc: Heiko Carstens , Ingo Molnar , LKML , Masami Hiramatsu , Martin Schwidefsky , "David S . Miller" , Paul Mundt , Steven Rostedt Subject: Re: [PATCH 2/3] tracing/kprobes: Make Kconfig dependencies generic Message-ID: <20100218154259.GC855@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> <8bd0f97a1002180702k12db615pa3096b273ce2c222@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <8bd0f97a1002180702k12db615pa3096b273ce2c222@mail.gmail.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: 2742 Lines: 62 On Thu, Feb 18, 2010 at 10:02:52AM -0500, Mike Frysinger wrote: > On Thu, Feb 18, 2010 at 09:50, 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. > > so should this new Kconfig option have an appropriate depends on > KPROBES or something ? No, kprobes events need KPROBES and the above one, but KPROBES alone can perfectely work without HAVE_REGS_AND_STACK_ACCESS_API. > > 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. > > i dont expect there to be per-function documentation here ... such > things below in the header files themselves (linux/regset.h is an > example of how to approach this). but having a tip of reading a file > or two (like HAVE_ARCH_TRACEHOOK) doesnt bit rot nearly as often. if > the common API expected of headers hasnt yet been split, then i guess > not much left to be done here. Yeah. Once it's split up from ptrace, we can think about a more dedicated header file and then it can be reasonable to put the header filename in the documentation. But not for now IMHO. -- 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/