Date: Wed, 21 Jul 2004 11:04:17 -0400 (EDT) From: Andrew Gallatin <gallatin@cs.duke.edu> To: Doug Rabson <dfr@nlsystems.com> Cc: freebsd-current@freebsd.org Subject: Re: Excellent job on the firewire support! Message-ID: <16638.34289.507068.283775@grasshopper.cs.duke.edu> In-Reply-To: <1090421941.7114.26.camel@builder02.qubesoft.com> References: <16634.47272.768935.436137@grasshopper.cs.duke.edu> <200407182039.10773.dfr@nlsystems.com> <16634.54674.966908.540880@grasshopper.cs.duke.edu> <200407182104.53221.dfr@nlsystems.com> <16638.32914.509773.486468@grasshopper.cs.duke.edu> <1090421941.7114.26.camel@builder02.qubesoft.com>
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Doug Rabson writes: > On Wed, 2004-07-21 at 15:41, Andrew Gallatin wrote: > > Doug Rabson writes: > > > Actually thats the only downside of dcons. It doesn't cut in until the > > > firewire controller attaches. It relies on the fact that the fwohci > > > driver allows access to physical memory from any node on the bus > > > (implemeted in hardware so you can examine the memory of a hung > > > machine). The dconschat program uses this feature to access the dcons > > > ring buffers in the target machine. > > > > Does remote access to physical memory require dcons to be loaded > > on the target? > > No. The remote access to physical memory is a hardware-implemented > feature of the firewire ohci hardware. Its enabled in fwohci_attach(). > In the long term, I would like to restrict this a bit but right now all > you have to have is fwohci loaded on the target machine. Yes, it seems like turning it off by default would be a good idea. Its very handy for debugging, but the security implications are rather alarming.. Thanks for the info! Drew
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