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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 22 Aug 2019 12:52:44 +0100 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x7MBqhY831260730 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 22 Aug 2019 11:52:43 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id EB44D4C052; Thu, 22 Aug 2019 11:52:42 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8BE844C050; Thu, 22 Aug 2019 11:52:42 +0000 (GMT) Received: from localhost (unknown [9.199.32.226]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 22 Aug 2019 11:52:42 +0000 (GMT) Date: Thu, 22 Aug 2019 17:22:42 +0530 From: "Naveen N. Rao" Subject: Re: [PATCH v5] arm64: implement KPROBES_ON_FTRACE To: Catalin Marinas , Jonathan Corbet , Jisheng Zhang , Masami Hiramatsu References: <20190822191351.3796aca8@xhacker.debian> In-Reply-To: <20190822191351.3796aca8@xhacker.debian> MIME-Version: 1.0 User-Agent: astroid/0.15.0 (https://github.com/astroidmail/astroid) X-TM-AS-GCONF: 00 x-cbid: 19082211-4275-0000-0000-0000035BDF6A X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19082211-4276-0000-0000-0000386E055A Message-Id: <1566474733.p35psfjpl2.naveen@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-08-22_07:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=616 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908220129 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190822_045252_673492_C9CC0D24 X-CRM114-Status: GOOD ( 18.81 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , "linux-doc@vger.kernel.org" , Peter Zijlstra , "linux-kernel@vger.kernel.org" , Steven Rostedt , Thomas Gleixner , "linux-arm-kernel@lists.infradead.org" Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Jisheng Zhang wrote: > KPROBES_ON_FTRACE avoids much of the overhead with regular kprobes as it > eliminates the need for a trap, as well as the need to emulate or > single-step instructions. > > Tested on berlin arm64 platform. > > ~ # mount -t debugfs debugfs /sys/kernel/debug/ > ~ # cd /sys/kernel/debug/ > /sys/kernel/debug # echo 'p _do_fork' > tracing/kprobe_events > > before the patch: > > /sys/kernel/debug # cat kprobes/list > ffffff801009fe28 k _do_fork+0x0 [DISABLED] > > after the patch: > > /sys/kernel/debug # cat kprobes/list > ffffff801009ff54 k _do_fork+0x4 [DISABLED][FTRACE] > > Signed-off-by: Jisheng Zhang Reviewed-by: Naveen N. Rao - Naveen _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel