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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 041B5C10DCE for ; Wed, 18 Mar 2020 09:46:14 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 44D1520674 for ; Wed, 18 Mar 2020 09:46:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 44D1520674 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 48j4t966YHzDqtG for ; Wed, 18 Mar 2020 20:46:09 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linux.ibm.com (client-ip=148.163.158.5; helo=mx0a-001b2d01.pphosted.com; envelope-from=ravi.bangoria@linux.ibm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 48j4qx0TqXzDqL5 for ; Wed, 18 Mar 2020 20:44:12 +1100 (AEDT) Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 02I9Ze5x131371 for ; Wed, 18 Mar 2020 05:44:09 -0400 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0a-001b2d01.pphosted.com with ESMTP id 2yua2ap1y8-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 18 Mar 2020 05:44:09 -0400 Received: from localhost by e06smtp04.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) Wed, 18 Mar 2020 09:44:02 -0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 02I9i1mA59441288 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 18 Mar 2020 09:44:01 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5779152052; Wed, 18 Mar 2020 09:44:01 +0000 (GMT) Received: from [9.203.170.80] (unknown [9.203.170.80]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id B804952065; Wed, 18 Mar 2020 09:43:10 +0000 (GMT) Subject: Re: [PATCH 10/15] powerpc/watchpoint: Use loop for thread_struct->ptrace_bps To: Christophe Leroy References: <20200309085806.155823-1-ravi.bangoria@linux.ibm.com> <20200309085806.155823-11-ravi.bangoria@linux.ibm.com> <0eeeac90-b5e3-722b-2d2c-bb95c81d851a@c-s.fr> From: Ravi Bangoria Date: Wed, 18 Mar 2020 15:13:01 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <0eeeac90-b5e3-722b-2d2c-bb95c81d851a@c-s.fr> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 20031809-0016-0000-0000-000002F31937 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 20031809-0017-0000-0000-000033569D96 Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138, 18.0.645 definitions=2020-03-18_03:2020-03-17, 2020-03-18 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 mlxlogscore=999 malwarescore=0 suspectscore=0 clxscore=1015 phishscore=0 priorityscore=1501 adultscore=0 bulkscore=0 spamscore=0 mlxscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2003180046 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: apopple@linux.ibm.com, mikey@neuling.org, Ravi Bangoria , peterz@infradead.org, oleg@redhat.com, npiggin@gmail.com, linux-kernel@vger.kernel.org, paulus@samba.org, jolsa@kernel.org, fweisbec@gmail.com, naveen.n.rao@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org, mingo@kernel.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" >> @@ -1628,6 +1628,9 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long usp, >>       void (*f)(void); >>       unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE; >>       struct thread_info *ti = task_thread_info(p); >> +#ifdef CONFIG_HAVE_HW_BREAKPOINT >> +    int i; >> +#endif > > Could we avoid all those #ifdefs ? > > I think if we make p->thread.ptrace_bps[] exist all the time, with a size of 0 when CONFIG_HAVE_HW_BREAKPOINT is not set, then we can drop a lot of #ifdefs. Hmm.. what you are saying seems possible. But IMO it should be done as independent series. Will work on it. > >>       klp_init_thread_info(p); >> @@ -1687,7 +1690,8 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long usp, >>       p->thread.ksp_limit = (unsigned long)end_of_stack(p); >>   #endif >>   #ifdef CONFIG_HAVE_HW_BREAKPOINT >> -    p->thread.ptrace_bps[0] = NULL; >> +    for (i = 0; i < nr_wp_slots(); i++) >> +        p->thread.ptrace_bps[i] = NULL; >>   #endif >>       p->thread.fp_save_area = NULL; >> diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c >> index f6d7955fc61e..e2651f86d56f 100644 >> --- a/arch/powerpc/kernel/ptrace.c >> +++ b/arch/powerpc/kernel/ptrace.c > > You'll have to rebase all this on the series https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=161356 which is about to go into powerpc-next Sure. Thanks for heads up. > >> @@ -2829,6 +2829,19 @@ static int set_dac_range(struct task_struct *child, >>   } >>   #endif /* CONFIG_PPC_ADV_DEBUG_DAC_RANGE */ >> +#ifdef CONFIG_HAVE_HW_BREAKPOINT >> +static int empty_ptrace_bp(struct thread_struct *thread) >> +{ >> +    int i; >> + >> +    for (i = 0; i < nr_wp_slots(); i++) { >> +        if (!thread->ptrace_bps[i]) >> +            return i; >> +    } >> +    return -1; >> +} >> +#endif > > What does this function do exactly ? I seems to do more than what its name suggests. It finds an empty breakpoint in ptrace_bps[]. But yeah, function name is misleading. I'll rename it to find_empty_ptrace_bp(). ... >> @@ -2979,10 +2993,10 @@ static long ppc_del_hwdebug(struct task_struct *child, long data) >>           return -EINVAL; >>   #ifdef CONFIG_HAVE_HW_BREAKPOINT >> -    bp = thread->ptrace_bps[0]; >> +    bp = thread->ptrace_bps[data - 1]; > > Is data checked somewhere to ensure it is not out of boundaries ? Or are we sure it is always within ? Yes. it's checked. See patch #9: @@ -2955,7 +2975,7 @@ static long ppc_del_hwdebug(struct task_struct *child, long data) } return rc; #else - if (data != 1) + if (data < 1 || data > nr_wp_slots()) return -EINVAL; #ifdef CONFIG_HAVE_HW_BREAKPOINT Thanks, Ravi