From patchwork Tue Oct 27 13:49:38 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 312112 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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 6A435C4363A for ; Tue, 27 Oct 2020 17:16:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0272420657 for ; Tue, 27 Oct 2020 17:16:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603818996; bh=n933nPjPhTwaAxa76XZlpZtEQm3PzxBaAMGkeZ3inPk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=YRP8O4vD7oEn9Yv/We+/ABmV7/Pbpebz0UVf+g5lDdUop8MJ3OIdjOSA3gGTEGD5X eE2Cf8yOSSKOSsjSSIp0/khL/Mt7uiSSIPEzHrtkwMQjq52sd1iSTmjM7hv/9ZBIeJ ADyhxHMz1pZt0Bn3+WjNUZEEXyusPdBi6ZxPkZu4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1783594AbgJ0O63 (ORCPT ); Tue, 27 Oct 2020 10:58:29 -0400 Received: from mail.kernel.org ([198.145.29.99]:59856 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1783588AbgJ0O63 (ORCPT ); Tue, 27 Oct 2020 10:58:29 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A7A4D20715; Tue, 27 Oct 2020 14:58:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603810708; bh=n933nPjPhTwaAxa76XZlpZtEQm3PzxBaAMGkeZ3inPk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FonqJtqBliuiF1ih7aX7y27SFTZDoxwMVUVwNbIJoU2CPSTqXjHlTVwdjiwd/1xd5 4hePBT3B4jT37mHUO0wA1G/Wr9xBC/O9r8jSqny9mBeRp4OhZdR73PYIwMxagX06iU 14vDINxkdIVGugFpnbMscy3gVJZdV9vm7aKeLqzI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mathieu Poirier , Mike Leach , Jeremy Linton , Suzuki K Poulose , Sasha Levin Subject: [PATCH 5.8 235/633] coresight: etm4x: Handle unreachable sink in perf mode Date: Tue, 27 Oct 2020 14:49:38 +0100 Message-Id: <20201027135533.708145459@linuxfoundation.org> X-Mailer: git-send-email 2.29.1 In-Reply-To: <20201027135522.655719020@linuxfoundation.org> References: <20201027135522.655719020@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Suzuki K Poulose [ Upstream commit 859d510e58dac94f0b204b7b5cccafbc130d2291 ] If the specified/hinted sink is not reachable from a subset of the CPUs, we could end up unable to trace the event on those CPUs. This is the best effort we could do until we support 1:1 configurations. Fail gracefully in such cases avoiding a WARN_ON, which can be easily triggered by the user on certain platforms (Arm N1SDP), with the following trace paths : CPU0 \ -- Funnel0 --> ETF0 --> / \ CPU1 \ MainFunnel CPU2 / \ / -- Funnel1 --> ETF1 --> / CPU1 $ perf record --per-thread -e cs_etm/@ETF0/u -- could trigger the following WARNING, when the event is scheduled on CPU2. [10919.513250] ------------[ cut here ]------------ [10919.517861] WARNING: CPU: 2 PID: 24021 at drivers/hwtracing/coresight/coresight-etm-perf.c:316 etm_event_start+0xf8/0x100 ... [10919.564403] CPU: 2 PID: 24021 Comm: perf Not tainted 5.8.0+ #24 [10919.570308] pstate: 80400089 (Nzcv daIf +PAN -UAO BTYPE=--) [10919.575865] pc : etm_event_start+0xf8/0x100 [10919.580034] lr : etm_event_start+0x80/0x100 [10919.584202] sp : fffffe001932f940 [10919.587502] x29: fffffe001932f940 x28: fffffc834995f800 [10919.592799] x27: 0000000000000000 x26: fffffe0011f3ced0 [10919.598095] x25: fffffc837fce244c x24: fffffc837fce2448 [10919.603391] x23: 0000000000000002 x22: fffffc8353529c00 [10919.608688] x21: fffffc835bb31000 x20: 0000000000000000 [10919.613984] x19: fffffc837fcdcc70 x18: 0000000000000000 [10919.619281] x17: 0000000000000000 x16: 0000000000000000 [10919.624577] x15: 0000000000000000 x14: 00000000000009f8 [10919.629874] x13: 00000000000009f8 x12: 0000000000000018 [10919.635170] x11: 0000000000000000 x10: 0000000000000000 [10919.640467] x9 : fffffe00108cd168 x8 : 0000000000000000 [10919.645763] x7 : 0000000000000020 x6 : 0000000000000001 [10919.651059] x5 : 0000000000000002 x4 : 0000000000000001 [10919.656356] x3 : 0000000000000000 x2 : 0000000000000000 [10919.661652] x1 : fffffe836eb40000 x0 : 0000000000000000 [10919.666949] Call trace: [10919.669382] etm_event_start+0xf8/0x100 [10919.673203] etm_event_add+0x40/0x60 [10919.676765] event_sched_in.isra.134+0xcc/0x210 [10919.681281] merge_sched_in+0xb0/0x2a8 [10919.685017] visit_groups_merge.constprop.140+0x15c/0x4b8 [10919.690400] ctx_sched_in+0x15c/0x170 [10919.694048] perf_event_sched_in+0x6c/0xa0 [10919.698130] ctx_resched+0x60/0xa0 [10919.701517] perf_event_exec+0x288/0x2f0 [10919.705425] begin_new_exec+0x4c8/0xf58 [10919.709247] load_elf_binary+0x66c/0xf30 [10919.713155] exec_binprm+0x15c/0x450 [10919.716716] __do_execve_file+0x508/0x748 [10919.720711] __arm64_sys_execve+0x40/0x50 [10919.724707] do_el0_svc+0xf4/0x1b8 [10919.728095] el0_sync_handler+0xf8/0x124 [10919.732003] el0_sync+0x140/0x180 Even though we don't support using separate sinks for the ETMs yet (e.g, for 1:1 configurations), we should at least honor the user's choice and handle the limitations gracefully, by simply skipping the tracing on ETMs which can't reach the requested sink. Fixes: f9d81a657bb8 ("coresight: perf: Allow tracing on hotplugged CPUs") Cc: Mathieu Poirier Cc: Mike Leach Reported-by: Jeremy Linton Tested-by: Jeremy Linton Signed-off-by: Suzuki K Poulose Signed-off-by: Mathieu Poirier Link: https://lore.kernel.org/r/20200916191737.4001561-11-mathieu.poirier@linaro.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/hwtracing/coresight/coresight-etm-perf.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c index 84f1dcb698272..c4b9898e28418 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.c +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c @@ -310,6 +310,16 @@ static void etm_event_start(struct perf_event *event, int flags) if (!event_data) goto fail; + /* + * Check if this ETM is allowed to trace, as decided + * at etm_setup_aux(). This could be due to an unreachable + * sink from this ETM. We can't do much in this case if + * the sink was specified or hinted to the driver. For + * now, simply don't record anything on this ETM. + */ + if (!cpumask_test_cpu(cpu, &event_data->mask)) + goto fail_end_stop; + path = etm_event_cpu_path(event_data, cpu); /* We need a sink, no need to continue without one */ sink = coresight_get_sink(path);