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=-3.8 required=3.0 tests=BAYES_00,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 95A22C433E9 for ; Wed, 6 Jan 2021 10:31:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4E8DC2311B for ; Wed, 6 Jan 2021 10:31:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726338AbhAFKa7 (ORCPT ); Wed, 6 Jan 2021 05:30:59 -0500 Received: from m43-15.mailgun.net ([69.72.43.15]:52760 "EHLO m43-15.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725828AbhAFKa6 (ORCPT ); Wed, 6 Jan 2021 05:30:58 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1609929036; h=Message-ID: Subject: Cc: To: From: Date: Content-Transfer-Encoding: Content-Type: MIME-Version: Sender; bh=gT+dnzCZdVFmgvncotTWR/Dha+MCgIOQiBwQEAjrLoA=; b=nNCqgQn3w9VO1qNc50zZCfTgwGFtcR1XycuCz+04C9PPfQVMnOnYnAQbuXwTDnMim0DLeYBu xlEhDX4SCK+uaCtPEFnPgKqPxPzYG2NvywE4N66IMtRFHKckDU4RusafDCVIFbOGp+3d5azE Tj+BIVLJfmVgfHDXCMA5C0bi8gQ= X-Mailgun-Sending-Ip: 69.72.43.15 X-Mailgun-Sid: WyI0MWYwYSIsICJsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n05.prod.us-east-1.postgun.com with SMTP id 5ff59123512813ac446a338b (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Wed, 06 Jan 2021 10:29:55 GMT Sender: tingwei=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 5A3BAC43462; Wed, 6 Jan 2021 10:29:54 +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: tingwei) by smtp.codeaurora.org (Postfix) with ESMTPSA id ECF9DC433C6; Wed, 6 Jan 2021 10:29:53 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Wed, 06 Jan 2021 18:29:53 +0800 From: tingwei@codeaurora.org To: Will Deacon , Mark Rutland Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Set DBGCLAIM when self-host debug is enabled Message-ID: <512a30e6cc6877687c10c0f9ccc3c4c5@codeaurora.org> X-Sender: tingwei@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Will and Mark, In recent implementation of save/restore ARM debug registers in EL2/EL3, we found it's necessary to know whether self-host debug is enabled so EL2/EL3 can avoid saving/restoring debug registers but no one is using debug. In ARM PSCI, it has one option to set DBGCLAIM[1] to 1 to indicate that debug is in use by a self-host debugger. Do you think it's resonable to add this to Kernel? For example, can we set DBGCLAIM[1] to 1 in enable_debug_monitors() and clear it in disable_debug_monitors(). Thanks, Tingwei -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project