From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6AC4BC43381 for ; Wed, 13 Mar 2019 01:18:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 39D41217F4 for ; Wed, 13 Mar 2019 01:18:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552439938; bh=RgwH5rsy0vHUZudERZYU4v2QMra3BIv3Y4JztssEOfI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=LIT2mmV4Kg+1Ffka9ZMAct9s+inWwRxQQ5kbiE2uxmrom1RlWfucMdceehGkPlUYS tuQ2J4y1dCdzJWdRNvGVv2Fo3J6zhZhP580ieeRCZxwJ3QjBn0VY4ay70SIe7jeyjO Mbt1wSEWu+BPdCNzglDtBirBbocUM/iQlPTIxqIU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726708AbfCMBSx (ORCPT ); Tue, 12 Mar 2019 21:18:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:33996 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725917AbfCMBSx (ORCPT ); Tue, 12 Mar 2019 21:18:53 -0400 Received: from devnote2 (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F11BD2171F; Wed, 13 Mar 2019 01:18:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552439931; bh=RgwH5rsy0vHUZudERZYU4v2QMra3BIv3Y4JztssEOfI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=2FUb4f4eniif1ed390uE14DJr2XNeFbFI6ozTKH6nUU2Okzjs4mKdxuxVM2Hlc8DY cn6dnyAn05FsLCL2LwlZDgSPBnssJe05KU05Z5tCIGPGTSowoI3pWW96NwOPI43dLE MpkhFhAQJWDVW7jRv29shlEtDY7RyqAN/uiGmCrc= Date: Wed, 13 Mar 2019 10:18:43 +0900 From: Masami Hiramatsu To: Joel Fernandes Cc: Steven Rostedt , Joel Fernandes , Daniel Colascione , Karim Yaghmour , Geert Uytterhoeven , Greg KH , LKML , Andrew Morton , Alexei Starovoitov , atish patra , Dan Williams , Dietmar Eggemann , Guenter Roeck , Jonathan Corbet , Kees Cook , Android Kernel Team , "open list:DOCUMENTATION" , "open list:KERNEL SELFTEST FRAMEWORK" , linux-trace-devel@vger.kernel.org, Manoj Rao , Masahiro Yamada , Masami Hiramatsu , Qais Yousef , Randy Dunlap , Shuah Khan , Yonghong Song Subject: Re: [PATCH v4 1/2] Provide in-kernel headers for making it easy to extend the kernel Message-Id: <20190313101843.800dd8d6a9babb635580ebdc@kernel.org> In-Reply-To: References: <20190308140251.GC25768@kroah.com> <20190309071648.GE3882@kroah.com> <20190309121141.GA30173@kroah.com> <3e84e1ef-e266-e983-5874-6c26ac7f38b8@opersys.com> <20190311193612.4f09bf11@oasis.local.home> <20190312003912.GA170478@google.com> <20190311212823.60684182@oasis.local.home> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-trace-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org On Mon, 11 Mar 2019 18:38:49 -0700 Joel Fernandes wrote: > On Mon, Mar 11, 2019 at 6:28 PM Steven Rostedt wrote: > > > > On Mon, 11 Mar 2019 20:39:12 -0400 > > Joel Fernandes wrote: > > > > > I think even though the kernel-headers can't have information about all data > > > structures, they do already contain a lot of data structure definitions we > > > need already. And anything needed can/should arguably be moved to include/ if > > > they are really needed for kernel extension by something "external" to the > > > kernel such as kernel modules or eBPF, right? > > > > That's not my worry. I would like to be able to easily walk data > > structures from within the kernel, without having to do a lot of work > > in userspace to get that information. The kprobe_events could then be > > passed type casts or such to access data fields of arguments to > > functions and such. > > Ok. > > > > In any case, such a solution such as what Steve suggested, still cannot do > > > what we can with headers - such as build kernel modules on the fly using the > > > C-compiler without any auto-generation of C code from any debug artifiacts. > > > Think systemtap working with the module-backend without any need for > > > linux-headers package on the file system. So such a solution would still be a > > > bit orthogonal in scope to what this proposed solution can solve IMO. > > > > > > > With the information I would like to have, it would be trivial to read > > the data to create the header files needed for modules. > > But there are macros and other #define things too. We lose all of them > and can't recreate them from just DWARF (AFAIK). Including > include/generated/autoconf.h which #defines the CONFIG options. For > that we either need headers, or full kernel's sources with build > artifacts. What kind of macros would you concern? > I do see a use case for the debug info you are talking about as you > mentioned for the kprobe_events argument list types, and I already > thought about it. But it does not seem to work for all the use cases I > am referring to here. But the eBPF is based on kprobe-events. What kind of usage would you expected? (with macros??) Thank you, -- Masami Hiramatsu