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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E8FE8C433F5 for ; Wed, 9 Mar 2022 11:36:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231815AbiCILg6 (ORCPT ); Wed, 9 Mar 2022 06:36:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57618 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229492AbiCILg4 (ORCPT ); Wed, 9 Mar 2022 06:36:56 -0500 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 62A71154D31 for ; Wed, 9 Mar 2022 03:35:58 -0800 (PST) Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 229BJ10F030689; Wed, 9 Mar 2022 11:35:36 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=date : from : subject : to : cc : references : in-reply-to : mime-version : message-id : content-type : content-transfer-encoding; s=pp1; bh=O2BUNUTzGb+7cQ8rm8DHMyjnM+LWM5EfmcO0Tz4pHzw=; b=Xjv54iykDrpDbsZcGuj81AUJEypYqnHR1rz8TI+lyQAewWuFK9fxoso/EO3KdJA6grAw 5YrgU/9v/HZ+9HDbgFacb20zYwfuR9uBPjMQzE1nzYUz/V1N3iRIPWKvKiLEcQbumj3O OHqFADbes+gvcjgtT34s5k4pvZ3NFE01i2pbYp7Td8QMPsgzcEi1fXAkCRW/GXHNLYK7 TehAImu6qsW5fHNIgQ+pdSZ/uMl6TUaQox/pnzwUgpeiFgs7dCBQTxE3BgtbL4LCIA6N +JlGmY5NeBqXseK5+0QjMuiwhVJWWTv4zGsPeMnI/PNwnIkSOR5Ew9LHDitbafgBUEXI Ug== Received: from ppma02fra.de.ibm.com (47.49.7a9f.ip4.static.sl-reverse.com [159.122.73.71]) by mx0a-001b2d01.pphosted.com with ESMTP id 3enww82uda-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 09 Mar 2022 11:35:36 +0000 Received: from pps.filterd (ppma02fra.de.ibm.com [127.0.0.1]) by ppma02fra.de.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 229BXlLq014484; Wed, 9 Mar 2022 11:35:33 GMT Received: from b06cxnps4074.portsmouth.uk.ibm.com (d06relay11.portsmouth.uk.ibm.com [9.149.109.196]) by ppma02fra.de.ibm.com with ESMTP id 3ekyg90h15-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 09 Mar 2022 11:35:33 +0000 Received: from d06av24.portsmouth.uk.ibm.com (d06av24.portsmouth.uk.ibm.com [9.149.105.60]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 229BZVXD50397678 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 9 Mar 2022 11:35:31 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5DF9042047; Wed, 9 Mar 2022 11:35:31 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E74E442042; Wed, 9 Mar 2022 11:35:30 +0000 (GMT) Received: from localhost (unknown [9.43.9.116]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 9 Mar 2022 11:35:30 +0000 (GMT) Date: Wed, 09 Mar 2022 17:05:29 +0530 From: "Naveen N. Rao" Subject: Re: [PATCH v1 2/4] powerpc/ftrace: Refactor ftrace_{regs_}caller To: Benjamin Herrenschmidt , Christophe Leroy , Michael Ellerman , Paul Mackerras Cc: "linux-kernel@vger.kernel.org" , "linuxppc-dev@lists.ozlabs.org" References: <9d7df9e4fc98a86051489f61d3c9bc67f92f7e27.1645099283.git.christophe.leroy@csgroup.eu> <1646326634.jzerx009p9.naveen@linux.ibm.com> <5c0a3a26-ee52-a4f7-9bc2-b38f27a12a76@csgroup.eu> In-Reply-To: <5c0a3a26-ee52-a4f7-9bc2-b38f27a12a76@csgroup.eu> MIME-Version: 1.0 User-Agent: astroid/4d6b06ad (https://github.com/astroidmail/astroid) Message-Id: <1646825481.p25t8oi12m.naveen@linux.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: EuvBYT_Q0yDRCRNv2BxaO7OCSMM--y8m X-Proofpoint-GUID: EuvBYT_Q0yDRCRNv2BxaO7OCSMM--y8m X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.816,Hydra:6.0.425,FMLib:17.11.64.514 definitions=2022-03-09_04,2022-03-04_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 lowpriorityscore=0 bulkscore=0 adultscore=0 clxscore=1015 priorityscore=1501 malwarescore=0 impostorscore=0 spamscore=0 mlxlogscore=986 phishscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2203090063 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Christophe Leroy wrote: >=20 >=20 > Le 03/03/2022 =C3=A0 17:59, Naveen N. Rao a =C3=A9crit=C2=A0: >> Christophe Leroy wrote: >> >> The ability to disable ftrace in certain code paths through=20 >> paca_struct->ftrace_enabled will also be relevant on ppc32 - it will be=20 >> nice if it can be introduced there. >=20 > Ah ? I understood from commit ea678ac627e0 ("powerpc64/ftrace: Add a=20 > field in paca to disable ftrace in unsafe code paths") that it was for=20 > when it runs in real mode. PPC32 doesn't run any C code in real mode. It likely isn't necessary in that case. >=20 > Are there any other situations that real_mode where we'd like to disable=20 > it ? If so we could use the thread_struct as we don't have paca on PPC32. For ppc64, we use this flag to disable certain paths in kvm, kexec,=20 mce/hmi and idle/hotplug. If none of those are problematic on ppc32,=20 then this isn't necessary. Thanks, - Naveen