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dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.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-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=1TZeVcjaCvBVqEgRB5Z83lSpgu8MAKv/tSlP06Tl/2M=; b=XOYEbGFMOoE3IAdMK6YulhZTM J4a1/+Fk4xZ2qJq2OPv8ZVpyOwBEZBg5sPymmS9r8euiCoTCf9r4CN3qcGX99AwZ0kVHqUqKC6cxK 0u4P7eW/7FPMUNSXJgOhaICzg0aD35TlJ3kg1I/Qc1kDdpuJ29fJvZLc9FJbOwG3cKyMkip0IXche 08SEsxmOziwBdxfHeDmAt8T47mwImsHF54pT4OpYfOEceH6Wo2Ey0c6AZMQl17KG3vxvfnNCyVLTN 2NrS28seMT7hGvggLHwRYn/kZ20cBppTb/PRyIBle6ttTOG0McAf+cO7kRTQayiPZmYppT9g0viRa nE9Ijyo3Q==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l7cHf-0008MD-2z; Thu, 04 Feb 2021 10:54:47 +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 1l7cHc-0008Lg-PS for linux-arm-kernel@lists.infradead.org; Thu, 04 Feb 2021 10:54:45 +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 6C2DBD6E; Thu, 4 Feb 2021 02:54:41 -0800 (PST) Received: from [10.57.60.124] (unknown [10.57.60.124]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 95B653F73B; Thu, 4 Feb 2021 02:54:37 -0800 (PST) Subject: Re: [PATCH v2 5/7] perf cs-etm: Add helper cs_etm__get_pid_fmt() To: Leo Yan References: <20210202163842.134734-1-leo.yan@linaro.org> <20210202163842.134734-6-leo.yan@linaro.org> <51a1e845-f9a4-3c6e-88a2-c105f5b5adfe@arm.com> <20210204034743.GE11059@leoy-ThinkPad-X240s> From: Suzuki K Poulose Message-ID: Date: Thu, 4 Feb 2021 10:54:24 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: <20210204034743.GE11059@leoy-ThinkPad-X240s> Content-Language: en-GB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210204_055444_952209_B84CA134 X-CRM114-Status: GOOD ( 26.87 ) 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: Mark Rutland , Denis Nikitin , Mathieu Poirier , Jonathan Corbet , Alexander Shishkin , Jiri Olsa , coresight@lists.linaro.org, John Garry , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo , Peter Zijlstra , Ingo Molnar , Namhyung Kim , Daniel Kiss , Will Deacon , linux-arm-kernel@lists.infradead.org, Mike Leach Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2/4/21 3:47 AM, Leo Yan wrote: > On Tue, Feb 02, 2021 at 11:19:22PM +0000, Suzuki Kuruppassery Poulose wrote: >> On 2/2/21 4:38 PM, Leo Yan wrote: >>> This patch adds helper function cs_etm__get_pid_fmt(), by passing >>> parameter "traceID", it returns the PID format. >>> >>> Signed-off-by: Leo Yan >>> --- >>> tools/perf/util/cs-etm.c | 43 ++++++++++++++++++++++++++++++++++++++++ >>> tools/perf/util/cs-etm.h | 1 + >>> 2 files changed, 44 insertions(+) >>> >>> diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c >>> index a2a369e2fbb6..8194ddbd01e5 100644 >>> --- a/tools/perf/util/cs-etm.c >>> +++ b/tools/perf/util/cs-etm.c >>> @@ -7,6 +7,7 @@ >>> */ >>> #include >>> +#include >>> #include >>> #include >>> #include >>> @@ -156,6 +157,48 @@ int cs_etm__get_cpu(u8 trace_chan_id, int *cpu) >>> return 0; >>> } >>> +/* >>> + * The returned PID format is presented by two bits: >>> + * >>> + * Bit ETM_OPT_CTXTID: CONTEXTIDR or CONTEXTIDR_EL1 is traced; >>> + * Bit ETM_OPT_CTXTID2: CONTEXTIDR_EL2 is traced. >>> + * >>> + * It's possible that these two bits are set together, this means the tracing >>> + * contains PIDs for both CONTEXTIDR_EL1 and CONTEXTIDR_EL2. >> >> This is a bit confusing. If both the bits are set, the session >> was run on an EL2 kernel. Thus, the PID is always in CONTEXTIDR_EL2. > > Sorry for confusion. I'd like to rephrase as: > > It's possible that the two bits ETM_OPT_CTXTID and ETM_OPT_CTXTID2 are > enabled at the same time when the session runs on an EL2 kernel. This > means the CONTEXTIDR_EL1 and CONTEXTIDR_EL2 both will be recorded in > the trace data, the tool will selectively use CONTEXTIDR_EL2 as PID. > >>> + */ >>> +int cs_etm__get_pid_fmt(u8 trace_chan_id, u64 *pid_fmt) >>> +{ >>> + struct int_node *inode; >>> + u64 *metadata, val; >>> + >>> + inode = intlist__find(traceid_list, trace_chan_id); >>> + if (!inode) >>> + return -EINVAL; >>> + >>> + metadata = inode->priv; >>> + >>> + if (metadata[CS_ETM_MAGIC] == __perf_cs_etmv3_magic) { >>> + val = metadata[CS_ETM_ETMCR]; >>> + /* CONTEXTIDR is traced */ >>> + if (val & BIT(ETM_OPT_CTXTID)) >>> + *pid_fmt = BIT(ETM_OPT_CTXTID); >>> + } else { >>> + val = metadata[CS_ETMV4_TRCCONFIGR]; >>> + >>> + *pid_fmt = 0; >>> + >>> + /* CONTEXTIDR_EL2 is traced */ >>> + if (val & (BIT(ETM4_CFG_BIT_VMID) | BIT(ETM4_CFG_BIT_VMID_OPT))) >>> + *pid_fmt = BIT(ETM_OPT_CTXTID2); >>> + >>> + /* CONTEXTIDR_EL1 is traced */ >>> + if (val & BIT(ETM4_CFG_BIT_CTXTID)) >> >> I haven't looked at how this gets used. But, Shouldn't this be : >> >> else if (val & BIT(ETM4_CFG_BIT_CTXTID)) ? > > Actually it's deliberately to set both bits ETM_OPT_CTXTID2 and > ETM_OPT_CTXTID if user has enable configs "contextid1" and > "contextid2". So this is exactly the reversed flow in the > function cs_etmv4_get_config(). The point is, we don't care if the user selected both options. What we care is, where can we find the PID. CONTEXTIDR_EL1 or CONTEXTIDR_EL2. As such, get_pid_fmt simply should make that decision and pass it on. So, if the CONTEXTIDR_EL2 is selected (which can only be done successfully on an EL2 kernel), thats our pid. So we should return the format for the PID here. i.e ETM_OPT_CTXTID2 OR ETM_OPT_CTXTID. But not both. Cheers Suzuki _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel