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 9E6F1C47077 for ; Wed, 15 Nov 2023 05:44:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234532AbjKOFo3 (ORCPT ); Wed, 15 Nov 2023 00:44:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37160 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229600AbjKOFo2 (ORCPT ); Wed, 15 Nov 2023 00:44:28 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 6C04FD1; Tue, 14 Nov 2023 21:44:24 -0800 (PST) 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 71AF1DA7; Tue, 14 Nov 2023 21:45:09 -0800 (PST) Received: from [10.163.37.87] (unknown [10.163.37.87]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A60603F6C4; Tue, 14 Nov 2023 21:44:16 -0800 (PST) Message-ID: <5bf73672-4094-490b-b0a9-b983d512c904@arm.com> Date: Wed, 15 Nov 2023 11:14:12 +0530 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [V14 3/8] drivers: perf: arm_pmuv3: Enable branch stack sampling framework Content-Language: en-US To: James Clark Cc: Mark Brown , Rob Herring , Marc Zyngier , Suzuki Poulose , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , linux-perf-users@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, will@kernel.org, catalin.marinas@arm.com, mark.rutland@arm.com References: <20231114051329.327572-1-anshuman.khandual@arm.com> <20231114051329.327572-4-anshuman.khandual@arm.com> <0020aa0d-e9a5-aef6-f33d-817da56411a3@arm.com> From: Anshuman Khandual In-Reply-To: <0020aa0d-e9a5-aef6-f33d-817da56411a3@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/14/23 15:28, James Clark wrote: > > > On 14/11/2023 05:13, Anshuman Khandual wrote: >> Branch stack sampling support i.e capturing branch records during execution >> in core perf, rides along with normal HW events being scheduled on the PMU. >> This prepares ARMV8 PMU framework for branch stack support on relevant PMUs >> with required HW implementation. >> > > [...] > >> - All armv8pmu_branch_xxxx() stub definitions have been moved inside >> include/linux/perf/arm_pmuv3.h for easy access from both arm32 and >> arm64 platforms >> > > This causes lots of W=1 build errors because the prototypes are in > arm_pmuv3.h, but arm_brbe.c doesn't include it. I guess these are the W=1 warnings you mentioned above. drivers/perf/arm_brbe.c:11:6: warning: no previous prototype for ‘armv8pmu_branch_reset’ [-Wmissing-prototypes] 11 | void armv8pmu_branch_reset(void) | ^~~~~~~~~~~~~~~~~~~~~ drivers/perf/arm_brbe.c:190:6: warning: no previous prototype for ‘armv8pmu_branch_save’ [-Wmissing-prototypes] 190 | void armv8pmu_branch_save(struct arm_pmu *arm_pmu, void *ctx) | ^~~~~~~~~~~~~~~~~~~~ drivers/perf/arm_brbe.c:236:6: warning: no previous prototype for ‘armv8pmu_branch_attr_valid’ [-Wmissing-prototypes] 236 | bool armv8pmu_branch_attr_valid(struct perf_event *event) | ^~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/perf/arm_brbe.c:269:5: warning: no previous prototype for ‘armv8pmu_task_ctx_cache_alloc’ [-Wmissing-prototypes] 269 | int armv8pmu_task_ctx_cache_alloc(struct arm_pmu *arm_pmu) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/perf/arm_brbe.c:279:6: warning: no previous prototype for ‘armv8pmu_task_ctx_cache_free’ [-Wmissing-prototypes] 279 | void armv8pmu_task_ctx_cache_free(struct arm_pmu *arm_pmu) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/perf/arm_brbe.c:303:6: warning: no previous prototype for ‘armv8pmu_branch_probe’ [-Wmissing-prototypes] 303 | void armv8pmu_branch_probe(struct arm_pmu *armpmu) | ^~~~~~~~~~~~~~~~~~~~~ drivers/perf/arm_brbe.c:449:6: warning: no previous prototype for ‘armv8pmu_branch_enable’ [-Wmissing-prototypes] 449 | void armv8pmu_branch_enable(struct arm_pmu *arm_pmu) | ^~~~~~~~~~~~~~~~~~~~~~ drivers/perf/arm_brbe.c:474:6: warning: no previous prototype for ‘armv8pmu_branch_disable’ [-Wmissing-prototypes] 474 | void armv8pmu_branch_disable(void) | ^~~~~~~~~~~~~~~~~~~~~~~ drivers/perf/arm_brbe.c:717:6: warning: no previous prototype for ‘armv8pmu_branch_read’ [-Wmissing-prototypes] 717 | void armv8pmu_branch_read(struct pmu_hw_events *cpuc, struct perf_event *event) Branch helpers are used in ARM PMU V3 driver i.e drivers/perf/arm_pmuv3.c. Whether the actual BRBE helper definitions, or their fallback stubs (when CONFIG_ARM64_BRBE is not enabled), need to be accessible from arm_pmuv3.c driver not from brbe.c implementations itself. > > It seems like the main reason you can't include arm_brbe.h in arm32 code > is because there are a load of inline functions and references to > registers in there. But these are only used in arm_brbe.c, so they don't Right, arm32 should not be exposed to BRBE internals via arm_brbe.h header. > need to be in the header anyway. Right, these are only used in arm_brbe.c > > If you removed the code from the header and moved it to the source file > you could move the brbe prototypes to the brbe header and it would be a > bit cleaner and more idiomatic. Alight, how about the following changes - build tested on arm32 and arm64. - Move BRBE helpers from arm_brbe.h into arm_brbe.c - Move armv8_pmu_xxx() declaration inside arm_brbe.h for arm64 (CONFIG_ARM64_BRBE) - Move armv8_pmu_xxx() stub definitions inside arm_pmuv3.c for arm32 (!CONFIG_ARM64_BRBE) - Include arm_brbe.h header both in arm_pmuv3.c and arm_brbe.c