From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.91] helo=mail.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Exim 4.30) id 1EFbgw-0001bH-68 for user-mode-linux-devel@lists.sourceforge.net; Wed, 14 Sep 2005 11:09:06 -0700 Received: from smtp001.mail.ukl.yahoo.com ([217.12.11.32]) by mail.sourceforge.net with smtp (Exim 4.44) id 1EFbgv-0002e9-Ga for user-mode-linux-devel@lists.sourceforge.net; Wed, 14 Sep 2005 11:09:06 -0700 From: Blaisorblade Subject: Re: [uml-devel] SYSEMU getting merged - but I'm in doubt References: <200509041702.18506.blaisorblade@yahoo.it> <432732E5.5010303@fujitsu-siemens.com> <43280E00.6030707@fujitsu-siemens.com> In-Reply-To: <43280E00.6030707@fujitsu-siemens.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200509142001.14318.blaisorblade@yahoo.it> Sender: user-mode-linux-devel-admin@lists.sourceforge.net Errors-To: user-mode-linux-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: The user-mode Linux development list List-Post: List-Help: List-Subscribe: , List-Archive: Date: Wed, 14 Sep 2005 20:01:13 +0200 To: Bodo Stroesser Cc: user-mode-linux-devel@lists.sourceforge.net, Jeff Dike , "Charles P. Wright" On Wednesday 14 September 2005 13:48, Bodo Stroesser wrote: > Bodo Stroesser wrote: > > OTOH, if the new API would reuse the same ptrace code, check_sysemu of > > the old > > binaries will fail on i386 > > (and I hope on x86_64, too). Nobody implemented sysemu for x86_64, at least to my knowledge. I hoped to finish skas first, but stopped on that problem. > > That means, > > sysemu again > > will be disabled. AFAICS, it will not refuse to run at all. (Not tested, > > taken from > > the code only) > > On s390 the check even might succeed accidentally, but that's no > > problem, as s390 > > isn't mainline yet, we can change check_sysemu() to avoid problems. > > There will > > never be an old binary for s390. > Some more points: > The new API must have PTRACE_SYSEMU _and_ PTRACE_SYSEMU_SINGLESTEP. Granted. > While with the old API SYSEMU_SINGLESTEP was inserted to improve security, > with the new one it will be necessary to allow singlestepping of processes > in UML-SKAS at all. Suppose a singlestepped userspace is stopped at a > syscall interception. Now UML needs to restart it with SYSEMU for syscall > emulation, but also wants to proceed with singlestepping. PTRACE_SYSEMU > wouldn't do the job, as it starts userspace in "normal" mode, no > singlestepping. Hmm, I hadn't looked at this detail... > Also, in tt new API's PTRACE_SYSEMU behaves as PTRACE_SYSCALL does, because > tracer uses PTRACE_CONT after syscall interception. So tt (do_syscall(), > ...) needs to be changed. PTRACE_SYSEMU_SINGLESTEP still should be used, as > if it's name were PTRACE_SYSCALL_SINGLESTEP. Ok, I think it's enough to warrant keeping the current behaviour and adding later an option, and/or removing it for now and merging it later. Unless somebody manages to fix all this in time. I don't think I'm likely to accomplish this, sorry. > Bodo -- Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!". Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894) http://www.user-mode-linux.org/~blaisorblade ___________________________________ Yahoo! Mail: gratis 1GB per i messaggi e allegati da 10MB http://mail.yahoo.it ------------------------------------------------------- SF.Net email is sponsored by: Tame your development challenges with Apache's Geronimo App Server. Download it for free - -and be entered to win a 42" plasma tv or your very own Sony(tm)PSP. Click here to play: http://sourceforge.net/geronimo.php _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel