From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 14310 invoked by alias); 23 Dec 2013 10:50:19 -0000 Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org Received: (qmail 14302 invoked by uid 89); 23 Dec 2013 10:50:19 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.8 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 X-HELO: mail4.hitachi.co.jp Received: from mail4.hitachi.co.jp (HELO mail4.hitachi.co.jp) (133.145.228.5) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Mon, 23 Dec 2013 10:50:18 +0000 Received: from mlsv2.hitachi.co.jp (unknown [133.144.234.166]) by mail4.hitachi.co.jp (Postfix) with ESMTP id 2B55333CC5; Mon, 23 Dec 2013 19:50:16 +0900 (JST) Received: from mfilter05.hitachi.co.jp by mlsv2.hitachi.co.jp (8.13.1/8.13.1) id rBNAoGr0009508; Mon, 23 Dec 2013 19:50:16 +0900 Received: from vshuts04.hitachi.co.jp (vshuts04.hitachi.co.jp [10.201.6.86]) by mfilter05.hitachi.co.jp (Switch-3.3.4/Switch-3.3.4) with ESMTP id rBNAoEp0004923; Mon, 23 Dec 2013 19:50:15 +0900 Received: from gxml20a.ad.clb.hitachi.co.jp (unknown [158.213.157.160]) by vshuts04.hitachi.co.jp (Postfix) with ESMTP id 1D57214003D; Mon, 23 Dec 2013 19:50:15 +0900 (JST) Received: from [10.198.194.57] by gxml20a.ad.clb.hitachi.co.jp (Switch-3.1.10/Switch-3.1.9) id 5BNA2EE8I00001970; Mon, 23 Dec 2013 19:50:14 +0900 Message-ID: <52B81562.5000607@hitachi.com> Date: Mon, 23 Dec 2013 10:50:00 -0000 From: Masami Hiramatsu User-Agent: Mozilla/5.0 (Windows NT 5.2; rv:13.0) Gecko/20120614 Thunderbird/13.0.1 MIME-Version: 1.0 To: Namhyung Kim Cc: Arnaldo Carvalho de Melo , Ingo Molnar , Srikar Dronamraju , David Ahern , lkml , "Steven Rostedt (Red Hat)" , Oleg Nesterov , "David A. Long" , systemtap@sourceware.org, yrl.pp-manager.tt@hitachi.com Subject: Re: [PATCH -tip 3/3] perf-probe: Use the actual address as a hint for uprobes References: <20131220100255.7169.19384.stgit@kbuild-fedora.novalocal> <20131220100302.7169.96318.stgit@kbuild-fedora.novalocal> <20131220180351.GC28878@ghostprotocols.net> <52B75F9E.7000802@hitachi.com> <87wqiwc8ly.fsf@sejong.aot.lge.com> In-Reply-To: <87wqiwc8ly.fsf@sejong.aot.lge.com> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2013-q4/txt/msg00487.txt.bz2 (2013/12/23 16:46), Namhyung Kim wrote: > On Mon, 23 Dec 2013 06:54:38 +0900, Masami Hiramatsu wrote: >> (2013/12/21 3:03), Arnaldo Carvalho de Melo wrote: >>> Em Fri, Dec 20, 2013 at 10:03:02AM +0000, Masami Hiramatsu escreveu: >> BTW, I'm not sure why debuginfo and nm shows symbol address + 0x400000, >> and why the perf's map/symbol can remove this offset. Could you tell me >> how it works? >> If I can get the offset (0x400000) from binary, I don't need this kind >> of ugly hacks... > > AFAIK the actual symbol address is what nm (and debuginfo) shows. But > perf adjusts symbol address to have a relative address from the start of > mapping (i.e. file offset) like below: > > sym.st_value -= shdr.sh_addr - shdr.sh_offset; Thanks! this is what I really need! > This way, we can handle mmap and symbol address almost uniformly > (i.e. ip = map->start + symbol->address). But this requires the mmap > event during perf record. For perf probe, we might need to synthesize > mapping info from the section/segment header since it doesn't have the > mmap event. Currently, the dso__new_map() just creates a map starts > from 0. I think the uprobe requires only the relative address, doesn't that? Thank you, -- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com