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=-17.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 0B4BCC47080 for ; Tue, 1 Jun 2021 13:10:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E123F613CB for ; Tue, 1 Jun 2021 13:10:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233925AbhFANMJ (ORCPT ); Tue, 1 Jun 2021 09:12:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:43060 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233064AbhFANMH (ORCPT ); Tue, 1 Jun 2021 09:12:07 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id D0C8161090; Tue, 1 Jun 2021 13:10:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1622553026; bh=lE3CSgPX33jsmcTIcv0+X8suVzuMTUCG2GCoG071wGk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=AD6aXOY5XSV0Sd3jePiq5wu9ot549JpP33alOWdxVeW7JxH3ZdDHMa+C6u4XmsuPo M7w9arxJs/BZ4ShY4f+ep19SvWHsLL01gb+bLKdKv85adY8Wl9kvW+/FeTUIgjVCcm MojMmqRgjSR1MHR38kNN1GNcsWrsnG4FgcJy2O/jiCHmgi8GJ+llWap5Mdf/tpX9gG co5Vebyg5KOBG4GXKlO0lZwGkxYDGWP/uGd8d/g44hMhb1fygSPTsvNO2Gxd17BYbY 8nnP4Avr/NvbNPMc1YJ1pZwsLhcipJWzbGVKEoOHCs6JJUbBjrto2n4CQv9oPYD7ei CFGbxSsacYEsw== Date: Tue, 1 Jun 2021 14:10:21 +0100 From: Will Deacon To: Qi Liu Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linuxarm@huawei.com, Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin Subject: Re: [PATCH v2 1/9] perf: Add EVENT_ATTR_ID to simplify event attributes Message-ID: <20210601131020.GD28025@willie-the-truck> References: <1621417919-6632-1-git-send-email-liuqi115@huawei.com> <1621417919-6632-2-git-send-email-liuqi115@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1621417919-6632-2-git-send-email-liuqi115@huawei.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 19, 2021 at 05:51:51PM +0800, Qi Liu wrote: > Similar EVENT_ATTR macros are defined in many PMU drivers, > like HiSilicon PMU driver, Arm PMU driver, Arm SMMU PMU > driver. So Add a generic macro to simplify code. > > Cc: Peter Zijlstra > Cc: Ingo Molnar > Cc: Arnaldo Carvalho de Melo > Cc: Mark Rutland > Cc: Alexander Shishkin > Signed-off-by: Qi Liu > --- > include/linux/perf_event.h | 6 ++++++ > kernel/events/core.c | 2 ++ > 2 files changed, 8 insertions(+) > > diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h > index f5a6a2f..d0aa74e 100644 > --- a/include/linux/perf_event.h > +++ b/include/linux/perf_event.h > @@ -1576,6 +1576,12 @@ static struct perf_pmu_events_attr _var = { \ > .event_str = _str, \ > }; > > +#define PMU_EVENT_ATTR_ID(_name, _id) \ > + (&((struct perf_pmu_events_attr[]) { \ > + { .attr = __ATTR(_name, 0444, perf_event_sysfs_show, NULL), \ > + .id = _id, } \ > + })[0].attr.attr) > + > #define PMU_FORMAT_ATTR(_name, _format) \ > static ssize_t \ > _name##_show(struct device *dev, \ > diff --git a/kernel/events/core.c b/kernel/events/core.c > index 0ac818b..330d9cc 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -13295,6 +13295,8 @@ ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr, > > if (pmu_attr->event_str) > return sprintf(page, "%s\n", pmu_attr->event_str); > + else > + return sprintf(page, "config=%#llx\n", pmu_attr->id); I think it's a really bad idea to hardcode this here. For example, I think this patch series breaks user ABI for the SMMU PMU which used to print: "event=0x%02llx\n" and by the looks of it many of the other conversions are unsound too. I'm all for a common macro, but the string needs to be determined by the driver. Will