From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 23423 invoked by alias); 26 Jul 2005 07:53:54 -0000 Mailing-List: contact systemtap-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sources.redhat.com Received: (qmail 23409 invoked by uid 22791); 26 Jul 2005 07:53:50 -0000 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit From: Roland McGrath To: Masami Hiramatsu Cc: Richard J Moore , SystemTAP , sugita@sdl.hitachi.co.jp, Satoshi Oshima Subject: Re: Hitachi djprobe mechanism In-Reply-To: Masami Hiramatsu's message of Tuesday, 26 July 2005 16:08:14 +0900 <42E5E15E.3050105@sdl.hitachi.co.jp> X-Zippy-Says: .. I want FORTY-TWO TRYNEL FLOATATION SYSTEMS installed within SIX AND A HALF HOURS!!! Message-Id: <20050726075346.F2D811809B2@magilla.sf.frob.com> Date: Tue, 26 Jul 2005 07:53:00 -0000 X-SW-Source: 2005-q3/txt/msg00121.txt.bz2 > I think Kerninst is similar in effect to djprobe. both of them copy > original code to a buffer and jump to the buffer. > However I think that the most unique feature of djprobe is use of > "bypass" route to safely insert code on SMP. > I cannot find SMP safety mechanism like "bypass" in kerninst papers > yet. If by this you mean inserting an int3 while writing the rest of the jmp instruction and then overwriting the first byte when the rest is in place, I recall reading about that in some kerninst paper to be sure.