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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham 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 842F3C43331 for ; Thu, 26 Mar 2020 03:32:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 639F220772 for ; Thu, 26 Mar 2020 03:32:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727688AbgCZDcT (ORCPT ); Wed, 25 Mar 2020 23:32:19 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:32584 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727575AbgCZDcS (ORCPT ); Wed, 25 Mar 2020 23:32:18 -0400 Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 02Q34Wt9043887 for ; Wed, 25 Mar 2020 23:32:18 -0400 Received: from e06smtp05.uk.ibm.com (e06smtp05.uk.ibm.com [195.75.94.101]) by mx0a-001b2d01.pphosted.com with ESMTP id 2ywd8f71wj-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 25 Mar 2020 23:32:17 -0400 Received: from localhost by e06smtp05.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 26 Mar 2020 03:32:07 -0000 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06avi18626390.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 02Q3V8iu30278096 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 26 Mar 2020 03:31:08 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A216A4C052; Thu, 26 Mar 2020 03:32:10 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 431FE4C046; Thu, 26 Mar 2020 03:32:07 +0000 (GMT) Received: from [9.199.59.209] (unknown [9.199.59.209]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 26 Mar 2020 03:32:07 +0000 (GMT) Subject: Re: [PATCH 07/15] powerpc/watchpoint: Get watchpoint count dynamically while disabling them To: Christophe Leroy Cc: mpe@ellerman.id.au, mikey@neuling.org, apopple@linux.ibm.com, paulus@samba.org, npiggin@gmail.com, naveen.n.rao@linux.vnet.ibm.com, peterz@infradead.org, jolsa@kernel.org, oleg@redhat.com, fweisbec@gmail.com, mingo@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Ravi Bangoria References: <20200309085806.155823-1-ravi.bangoria@linux.ibm.com> <20200309085806.155823-8-ravi.bangoria@linux.ibm.com> From: Ravi Bangoria Date: Thu, 26 Mar 2020 09:02:05 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 20032603-0020-0000-0000-000003BB82B9 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 20032603-0021-0000-0000-000022140B34 Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.645 definitions=2020-03-25_13:2020-03-24,2020-03-25 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 suspectscore=0 malwarescore=0 mlxlogscore=999 spamscore=0 lowpriorityscore=0 phishscore=0 adultscore=0 priorityscore=1501 bulkscore=0 impostorscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2003260013 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/18/20 12:27 PM, Ravi Bangoria wrote: > > > On 3/17/20 4:02 PM, Christophe Leroy wrote: >> >> >> Le 09/03/2020 à 09:57, Ravi Bangoria a écrit : >>> Instead of disabling only one watchpooint, get num of available >>> watchpoints dynamically and disable all of them. >>> >>> Signed-off-by: Ravi Bangoria >>> --- >>>   arch/powerpc/include/asm/hw_breakpoint.h | 15 +++++++-------- >>>   1 file changed, 7 insertions(+), 8 deletions(-) >>> >>> diff --git a/arch/powerpc/include/asm/hw_breakpoint.h b/arch/powerpc/include/asm/hw_breakpoint.h >>> index 980ac7d9f267..ec61e2b7195c 100644 >>> --- a/arch/powerpc/include/asm/hw_breakpoint.h >>> +++ b/arch/powerpc/include/asm/hw_breakpoint.h >>> @@ -75,14 +75,13 @@ extern void ptrace_triggered(struct perf_event *bp, >>>               struct perf_sample_data *data, struct pt_regs *regs); >>>   static inline void hw_breakpoint_disable(void) >>>   { >>> -    struct arch_hw_breakpoint brk; >>> - >>> -    brk.address = 0; >>> -    brk.type = 0; >>> -    brk.len = 0; >>> -    brk.hw_len = 0; >>> -    if (ppc_breakpoint_available()) >>> -        __set_breakpoint(&brk, 0); >>> +    int i; >>> +    struct arch_hw_breakpoint null_brk = {0}; >>> + >>> +    if (ppc_breakpoint_available()) { >> >> I think this test should go into nr_wp_slots() which should return zero when no breakpoint is available. > > Seems possible. Will change it in next version. Once we move ppc_breakpoint_available() logic into nr_wp_slots(), 'dawr_force_enable' variable is checked in nr_wp_slots() before it gets initialized in dawr_force_setup(): start_kernel() |-> perf_event_init() | init_hw_breakpoint() | hw_breakpoint_slots() | nr_wp_slots() | /* Check dawr_force_enable variable */ | |-> arch_call_rest_init() rest_init() kernel_thread(kernel_init, ...) ... kernel_init() kernel_init_freeable() ... do_one_initcall() dawr_force_setup() /* Set dawr_force_enable = true */ Because of this, hw-breakpoint infrastructure is initialized with no DAWRs. So I'm thinking to keep the code as it is i.e. not moving ppc_breakpoint_available() test inside nr_wp_slots(). Ravi