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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 933D4C433DF for ; Mon, 8 Jun 2020 14:08:01 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 574C22076A for ; Mon, 8 Jun 2020 14:08:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="lt56JZRj"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="Ye48iH5q" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 574C22076A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-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=bombadil.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:Message-ID:References:In-Reply-To:Subject:To:From: Date:MIME-Version:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=ls+ZjZIlOHmCCdtd+0+DS0bYFMZ0fITabhHZocm7PhI=; b=lt56JZRjjddUsBimGbFPQOT8N k07FSYrLbjbUvUis9RZkHp9S9Xt4daJa8Tc3LTy6Wu3ZgJVQ9HbUSbRNfB2VlgBUO9pegWkaX4yiG EW+Vv7Brxkb8A/FHzcmn2Pe2Ub8m2+35ilv3q36GMAQEl/T+Fg/nFC/LvenNcOO4uQEeph5ep/e85 AtUDIeEel4dyzgR1CY+gqIq3AgtryzsV6Bh/q9rYxzwtRLa0UXWHqS4DyYE98OvGecLN4tS6M9PA8 poQS2Zv4+syVgYrAKtCi9K+FTlB/cJ5JD2oFkpKG7dijMYpR/jf1BOEwSnCp7IORsTlBVmVepC5ad 52byo+gAw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jiIRN-0006Uq-1x; Mon, 08 Jun 2020 14:07:53 +0000 Received: from mail27.static.mailgun.info ([104.130.122.27]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jiIRH-0006US-9s for linux-arm-kernel@lists.infradead.org; Mon, 08 Jun 2020 14:07:50 +0000 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1591625268; h=Message-ID: References: In-Reply-To: Subject: Cc: To: From: Date: Content-Transfer-Encoding: Content-Type: MIME-Version: Sender; bh=2lAq2rIQvCTa/HMObWUZHG77iDOvmKG/k0U9on+s/5c=; b=Ye48iH5q4fvbe98p/RjVV7wCWgtuOY+A78ETlM59YzgSX8t0GWXh0d3VQBGbhWGtZ5aWE3gd h3egPcNh8t0h9lr3QOiRl9rYNe9yWPkTFrchzSi/zY9osEXXF84k1h5yPBLmHqC3VO7Xa+yg k0tZ4W/BgzLr5V3I3jn4r15+W3s= X-Mailgun-Sending-Ip: 104.130.122.27 X-Mailgun-Sid: WyJiYzAxZiIsICJsaW51eC1hcm0ta2VybmVsQGxpc3RzLmluZnJhZGVhZC5vcmciLCAiYmU5ZTRhIl0= Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n13.prod.us-east-1.postgun.com with SMTP id 5ede4631f9a707134586e162 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Mon, 08 Jun 2020 14:07:45 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 90DD3C4339C; Mon, 8 Jun 2020 14:07:44 +0000 (UTC) Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: saiprakash.ranjan) by smtp.codeaurora.org (Postfix) with ESMTPSA id 05A65C433C6; Mon, 8 Jun 2020 14:07:44 +0000 (UTC) MIME-Version: 1.0 Date: Mon, 08 Jun 2020 19:37:43 +0530 From: Sai Prakash Ranjan To: Mathieu Poirier , Mike Leach Subject: Re: [PATCH 2/2] coresight: tmc: Add shutdown callback for TMC ETR/ETF In-Reply-To: References: <28123d1e19f235f97555ee36a5ed8b52d20cbdea.1590947174.git.saiprakash.ranjan@codeaurora.org> <20200601212858.GB24287@xps15> <6d759cc28628ea72767c1304883630eb@codeaurora.org> <4a09cd2e054836d85f2e024ca4435e91@codeaurora.org> <1a5a6a6d-b86d-df45-cf91-7081e70d88a3@arm.com> <20200603174426.GA23165@xps15> Message-ID: X-Sender: saiprakash.ranjan@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200608_070748_638423_287B7225 X-CRM114-Status: GOOD ( 15.17 ) 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: Will Deacon , Suzuki K Poulose , linux-arm-msm@vger.kernel.org, Coresight ML , Linux Kernel Mailing List , Stephen Boyd , Robin Murphy , linux-arm-kernel Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Mathieu, Mike On 2020-06-04 12:57, Sai Prakash Ranjan wrote: > [...] >> >> Robin has a point - user space is long gone at this time. As such the >> first >> question to ask is what kind of CS session was running at the time the >> system >> was shutting down. Was it a perf session of a sysfs session? >> >> I'm guessing it was a sysfs session because user space has been blown >> away a >> while back and part of that process should have killed all perf >> sessions. > > I was enabling trace via sysfs. > >> >> If I am correct then simply switching off the ETR HW in the shutdown() >> amba bus >> callback should be fine - otherwise Mike's approach is mandatory. >> There is >> also the exchange between Robin and Sai about removing the SMMU >> shutdown >> callback, but that thread is still incomplete. >> > > If Robin is hinting at removing SMMU shutdown callback, then I think > adding > all these shutdown callbacks to all clients of SMMU can be avoided. Git > blaming > the thing shows it was added to avoid some kexec memory corruption. > I think I misread the cryptic hint from Robin and it is not right to remove SMMU shutdown callback. For more details on why that was a bad idea and would break kexec, please refer to [1]. As for the coresight, can I disable the ETR only in the tmc shutdown callback or are we still concerned about the userspace coming into picture? [1] https://lore.kernel.org/patchwork/patch/1253131/ Thanks, Sai -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel