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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 178E3C433F5 for ; Thu, 3 Feb 2022 12:31:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date: Message-ID:From:References:Cc:To:Subject:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=qJJvBSR3C4vRFjaZXaGJQumOLmGap8RieUv12UiMk2g=; b=P821CNp9vUKSapbflbvkJwo7vi FQnrvIotHltpUkkrGFMd55yctFiNCr6oROZK5v6IkPj+CCpme5PC8i3UiR6BQ50ACULGcYcHy9Uma u6wWGY80XZYO5nUC7r9fnGHFWMyC2INe5mOxAQalwOX5aoXT3nqWhxV++uyQIqkndf/6M8nby+7Pj f0q34FfeLIql2DLDKIQ04+H9iz3TG1ozfPxgL+3b7WWkOaxREB6shA//SCXRcI1F/zSr0yVW0K9F0 Th6yp+r9hpjNsNNlz07u4gjzY606QBi/K0fCwYZlg8NW8849rgd1OYVk3GXKYKKnJsULJtoQH6D6v VEkmxCvA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nFbEy-001GSs-Hk; Thu, 03 Feb 2022 12:29:33 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nFb3D-001BrB-EX for linux-arm-kernel@lists.infradead.org; Thu, 03 Feb 2022 12:17:25 +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 4AD3311D4; Thu, 3 Feb 2022 04:17:22 -0800 (PST) Received: from [10.163.44.35] (unknown [10.163.44.35]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1C6D03F774; Thu, 3 Feb 2022 04:17:19 -0800 (PST) Subject: Re: [PATCH] coresight: trbe: Move check for kernelspace unmapped at EL0 to probe To: Sudeep Holla Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Mathieu Poirier , Suzuki K Poulose , Mike Leach , Leo Yan , coresight@lists.linaro.org References: <20220201122212.3009461-1-sudeep.holla@arm.com> <01a43ba2-a633-f215-a688-2bda293b5a47@arm.com> <20220203101111.mx3o5kmo2bkjirn4@bogus> From: Anshuman Khandual Message-ID: <8fe55cd3-489c-4826-c3dd-a6a4641c47da@arm.com> Date: Thu, 3 Feb 2022 17:47:15 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20220203101111.mx3o5kmo2bkjirn4@bogus> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220203_041723_643344_0DABD4FB X-CRM114-Status: GOOD ( 11.83 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2/3/22 5:34 PM, Sudeep Holla wrote: >> Could you please add a similar comment like SPE driver regarding how >> the TRBE buffer will be inaccessible, if kernel gets unmapped at EL0 >> and trace capture will terminate. >> > Sure I can add that. But if the device probe fails, will you be able to even > start the trace capture, sorry I didn't get what you mean by "trace capture > will terminate". I assume it must be "trace capture is not possible or not > allowed" IIUC. I guess the comment should be framed like - what might happen if the following code block which checks for arm64_kernel_unmapped_at_el0() is not present. If TRBE gets enabled along with kernel unmapping at EL0 supported, trace capture will terminate. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel