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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0FC67C43334 for ; Tue, 28 Jun 2022 07:40:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229835AbiF1HkP (ORCPT ); Tue, 28 Jun 2022 03:40:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39172 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229896AbiF1HkO (ORCPT ); Tue, 28 Jun 2022 03:40:14 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id B3B802A413; Tue, 28 Jun 2022 00:40:11 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 73B0D152B; Tue, 28 Jun 2022 00:40:11 -0700 (PDT) Received: from [10.162.42.7] (unknown [10.162.42.7]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C95CD3F66F; Tue, 28 Jun 2022 00:40:07 -0700 (PDT) Message-ID: <967c0a4f-c864-21ec-33f1-5e3943a42409@arm.com> Date: Tue, 28 Jun 2022 13:10:05 +0530 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH 0/8] arm64/perf: Enable branch stack sampling Content-Language: en-US To: Will Deacon Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, peterz@infradead.org, acme@kernel.org, mark.rutland@arm.com, Catalin Marinas , James Clark , Rob Herring , Marc Zyngier , Ingo Molnar , linux-perf-users@vger.kernel.org References: <20220613100119.684673-1-anshuman.khandual@arm.com> <20220627110105.GF22095@willie-the-truck> From: Anshuman Khandual In-Reply-To: <20220627110105.GF22095@willie-the-truck> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-perf-users@vger.kernel.org On 6/27/22 16:31, Will Deacon wrote: > On Mon, Jun 13, 2022 at 03:31:11PM +0530, Anshuman Khandual wrote: >> This series enables perf branch stack sampling support on arm64 platform >> via a new arch feature called Branch Record Buffer Extension (BRBE). All >> relevant register definitions could be accessed here. >> >> https://developer.arm.com/documentation/ddi0601/2021-12/AArch64-Registers >> >> This series applies on v5.19-rc2 after the BRBE related perf ABI changes series >> (V6) that was posted earlier. >> >> https://lore.kernel.org/linux-arm-kernel/20220610035101.424112-1-anshuman.khandual@arm.com/ >> >> Following issues remain inconclusive >> >> - Jame's concerns regarding permission inadequacy related to perfmon_capable() >> - Jame's concerns regarding using perf_event_paranoid along with perfmon_capable() > > afaict, the capability stuff remains unresolved with the SPE driver, so I'd > really like to see it fixed there first before we add more broken drivers. > > https://lore.kernel.org/r/20220118100702.GB16547@willie-the-truck Hello Will, I did go through the above mentioned thread, but could not understand (clear enough) - what needs to be done. Could you please help summerize the problem and possible solutions which I can start looking into. Thank you. - Anshuman