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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED autolearn=ham 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 36FE3C28CF6 for ; Fri, 3 Aug 2018 17:57:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DF9882177F for ; Fri, 3 Aug 2018 17:57:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DF9882177F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bell.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729681AbeHCTy0 (ORCPT ); Fri, 3 Aug 2018 15:54:26 -0400 Received: from simcoe208srvr.owm.bell.net ([184.150.200.208]:43918 "EHLO torfep02.bell.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728079AbeHCTy0 (ORCPT ); Fri, 3 Aug 2018 15:54:26 -0400 Received: from bell.net torfep02 184.150.200.158 by torfep02.bell.net with ESMTP id <20180803175705.YMQI32387.torfep02.bell.net@torspm02.bell.net>; Fri, 3 Aug 2018 13:57:05 -0400 Received: from [192.168.2.49] (really [70.53.62.189]) by torspm02.bell.net with ESMTP id <20180803175705.QJXG31064.torspm02.bell.net@[192.168.2.49]>; Fri, 3 Aug 2018 13:57:05 -0400 Subject: Re: [PATCH] parisc: prefer _THIS_IP_ and _RET_IP_ statement expressions To: Nick Desaulniers Cc: deller@gmx.de, jejb@parisc-linux.org, Nathan Chancellor , Thomas Gleixner , Pravin Shedge , Kate Stewart , Greg KH , linux-parisc@vger.kernel.org, LKML References: <20180801182258.17834-1-ndesaulniers@google.com> <78c667f9-5c8b-3835-83eb-4b59e27e4f7e@bell.net> <54b2139b-53d2-01c5-f240-93a692cdbc59@bell.net> <536ef1b1-cfa2-f66d-4261-fb8405964632@bell.net> From: John David Anglin Message-ID: <80743c1c-2a8c-7bce-2068-24c63790eba7@bell.net> Date: Fri, 3 Aug 2018 13:57:05 -0400 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Cloudmark-Analysis: v=2.2 cv=DZT4krlW c=1 sm=0 tr=0 a=VCUqJnZSONuD0ISaPFNHjQ==:17 a=IkcTkHD0fZMA:10 a=dapMudl6Dx4A:10 a=FBHGMhGWAAAA:8 a=hkL0fQ1ZxZnohGXfZUwA:9 a=QEXdDO2ut3YA:10 a=9gvnlMMaQFpL9xblJ6ne:22 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018-08-02 4:31 PM, Nick Desaulniers wrote: > If I understand your point correctly, is it that you're saying that > _THIS_IP_ should be implemented in terms of inline assembly (as in > what current_text_addr() is currently)? If that's what you mean and > I'm understanding correctly, my point is that we should be preferring > the generic C implementation as that's what's being used in most > places currently, so if it was broken you'd likely already know about > it. Unless unwinding is truly broken by the additional label, I don't > think we need an inline assembly implementation of current_text_addr() > for parisc (or any arch for that matter). If we do, then it can be > localized to the parisc unwinding code, that way it can be > consolidated everywhere else for every other arch. The label breaks the unwind data, not the unwind code.  So, localizing the use of current_text_addr() to the parisc unwind code doesn't help. Personally, I prefer the implementation of current_text_addr() because: 1) The generated code is smaller, and 2) it doesn't introduce any unnecessary labels into the text. As noted, these labels can cause issues with unwinding. Dave -- John David Anglin dave.anglin@bell.net