From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by sourceware.org (Postfix) with ESMTPS id BB7783858418 for ; Mon, 2 May 2022 17:19:03 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org BB7783858418 Received: from pps.filterd (m0127361.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 242HDSEu037149 for ; Mon, 2 May 2022 17:19:03 GMT Received: from ppma04dal.us.ibm.com (7a.29.35a9.ip4.static.sl-reverse.com [169.53.41.122]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3ftkgt02x5-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 02 May 2022 17:19:02 +0000 Received: from pps.filterd (ppma04dal.us.ibm.com [127.0.0.1]) by ppma04dal.us.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 242HHrve016956 for ; Mon, 2 May 2022 17:19:02 GMT Received: from b03cxnp08028.gho.boulder.ibm.com (b03cxnp08028.gho.boulder.ibm.com [9.17.130.20]) by ppma04dal.us.ibm.com with ESMTP id 3frvr9ab3e-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 02 May 2022 17:19:02 +0000 Received: from b03ledav005.gho.boulder.ibm.com (b03ledav005.gho.boulder.ibm.com [9.17.130.236]) by b03cxnp08028.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 242HJ0HS34996496 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 2 May 2022 17:19:00 GMT Received: from b03ledav005.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1196CBE053; Mon, 2 May 2022 17:19:00 +0000 (GMT) Received: from b03ledav005.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 72C1DBE04F; Mon, 2 May 2022 17:18:59 +0000 (GMT) Received: from sig-9-65-246-225.ibm.com (unknown [9.65.246.225]) by b03ledav005.gho.boulder.ibm.com (Postfix) with ESMTP; Mon, 2 May 2022 17:18:59 +0000 (GMT) Message-ID: <02f8062ee4eb348878f76ba7f2cb1a7a518db763.camel@vnet.ibm.com> Subject: Re: [PATCH] PowerPC: bp-permanent.exp, kill-after-signal fix From: will schmidt To: Ulrich Weigand , "gdb-patches@sourceware.org" , "cel@us.ibm.com" Cc: Rogerio Alves Cardoso Date: Mon, 02 May 2022 12:18:58 -0500 In-Reply-To: <1dcf7a9570b13e68d035840261dc1dc9a9baad5c.camel@de.ibm.com> References: <1dcf7a9570b13e68d035840261dc1dc9a9baad5c.camel@de.ibm.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5 (3.28.5-18.el8) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: j8IfxhmRC5nwjsgJ5cIqKQeN8rVP4Xoi X-Proofpoint-ORIG-GUID: j8IfxhmRC5nwjsgJ5cIqKQeN8rVP4Xoi X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.858,Hydra:6.0.486,FMLib:17.11.64.514 definitions=2022-05-02_05,2022-05-02_03,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 impostorscore=0 phishscore=0 mlxscore=0 adultscore=0 mlxlogscore=824 spamscore=0 clxscore=1015 bulkscore=0 priorityscore=1501 suspectscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2205020128 X-Spam-Status: No, score=-6.0 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_EF, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 02 May 2022 17:19:05 -0000 On Mon, 2022-05-02 at 15:10 +0000, Ulrich Weigand wrote: > will schmidt wrote: > > > So.. Is this directly related to the amount of kernel code > > handling > > the signals? i.e. Would this need to be updated if another > instruction > > is added to the kernel code? > > To clarify, this not *kernel* code, it's user space code, but code > that is placed by the kernel into user space (in the vdso). > > Many platforms today use the vdso in the signal *return* path, but > Power seems special in that it is using a vdso instruction also to > *enter* a signal handler in the first place. (So instead of the > kernel directly dispatching to the installed signal handler, it > first dispatches to vdso code which in turn calls into the signal > handler.) > > Reading the kernel logs, this seems to have been a performance > optimization to prevent the call/return stack from getting out > of balance. > > That vdso code path when entering a signal handler is just a > single "brctl"; I don't see any particular reason why this would > ever need to become any longer. Ok, thanks for clarifying. I look forward to seeing the updated comments in the next version of the patch by Carl. :-) Thanks -Will > > Bye, > Ulrich >