From patchwork Tue Aug 18 19:29:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Suzuki K Poulose X-Patchwork-Id: 11722131 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5DC1614F6 for ; Tue, 18 Aug 2020 19:31:56 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 33299206B5 for ; Tue, 18 Aug 2020 19:31:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="qe3AcqEz" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 33299206B5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject:To:From: Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender :Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=10xVtw10cBdXiqdtCk21AZBof7ahCmE8+wkyl0BoW8A=; b=qe3AcqEzciUBUtXX33v9QaNIQe dEoMdO6RKTmZTlbS/spb2HQ6Nm8ZjfBC68kXWjvPPw4+SyDhQBXKZmvag8ylkCVfMMIwkQ4ZYlg7S aMy85ZPW5m9kFjBP2a0LBDuCScxNudcRcokR28ADN0BWcF/iWa8q9+dsugnVXpu6n+n7qnYGzBjjG BYIK4v+5CfcYS1LXxF9rM9EbfPEF3lVADR6OxopZpLLuwM+vDdbA5mc08TmtA+fESi3yZhA7Ys8f+ 0aQTpChAv5hFmye8/WABWK1qfDZw962dbaUe01raAbKnQ7rkTfXhSinBgBu5y7cf+zcy1vIi0Z/Io Ot2cd34Q==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1k87JF-00026x-4g; Tue, 18 Aug 2020 19:30:13 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1k87JB-00025d-B7 for linux-arm-kernel@lists.infradead.org; Tue, 18 Aug 2020 19:30:10 +0000 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 3BF6B31B; Tue, 18 Aug 2020 12:30:02 -0700 (PDT) Received: from ewhatever.cambridge.arm.com (ewhatever.cambridge.arm.com [10.1.197.1]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 2D1BD3F71F; Tue, 18 Aug 2020 12:30:01 -0700 (PDT) From: Suzuki K Poulose To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] coresight: etm4x: Handle unreachable sink in perf mode Date: Tue, 18 Aug 2020 20:29:31 +0100 Message-Id: <20200818192931.168584-1-suzuki.poulose@arm.com> X-Mailer: git-send-email 2.24.1 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200818_153009_566849_27C590D0 X-CRM114-Status: GOOD ( 14.72 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [217.140.110.172 listed in list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mathieu.poirier@linaro.org, Suzuki K Poulose , coresight@lists.linaro.org, linux-kernel@vger.kernel.org, jeremy.linton@arm.com, Mike Leach Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org 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, like : [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 Fixes: f9d81a657bb8 ("coresight: perf: Allow tracing on hotplugged CPUs") Reported-by: Jeremy Linton Cc: Mathieu Poirier Cc: Mike Leach Signed-off-by: Suzuki K Poulose Tested-by: Jeremy Linton --- 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 1a3169e69bb1..9d61a71da96f 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.c +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c @@ -321,6 +321,16 @@ 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);