On Friday 24 March 2006 01:40, Jason Lunz wrote: > On Thu, Mar 23, 2006 at 06:50:44PM -0500, Jeff Dike wrote: > > You can make some progress by disabling CONFIG_MODE_TT - that will > > cause UML to load at a normal address rather than the 0xa0000000 that > > CONFIG_MODE_TT will force. > > > > That should get you to the point of trying to run init. > > > > Since you have skas3, my guess is that UML will be fine at that point. > > > > On a non-skas3 host, it will run in skas0 mode, and will expect to be > > able to map a couple of pages at the top of the process address space > > (hardcoded to 0xbfffe000 and 0xbffff000). These offsets would need to > > be calculated based on the host's split in order for skas0 to work. > > So I guess getting a 2.4 uml to work on any split other than 1G/3G is > pretty unlikely. Oh well, I already knew 2.4 was on its way out. So this > might be the thing that really forces me to use 2.6.
No, that's wrong - what David Lang described: > I don't know about other non-standard memory configs, but there is an > explicit config option when compiling a uml kernel to support the 2G/2G > memory split. was also supported by UML 2.4. I think unusual split and the UML trivial support for that were born and used when 4G/4G didn't exist yet (or maybe not even highmem?). > 2.4 support aside, my aim is to have a single uml binary that will work > on arbitrary host kernels. How difficult will it be to implement support > for dynamic offsets for these pages in skas0? I don't think it's easy - however, it can be done. Below my idea - Jeff, please comment on this In assembly. It goes like this: call label /*this is coded like a relative jump, i.e. call +1*/ label: pop $eax /*we got the saved EIP*/ /* Now we can round EIP and subtract an offset to calculate the data page location. */ The only problem is that it must be done in assembly and at times this must be redone (we don't have enough registers to save the value across a 6-param syscall), and touching this code is a bit dangerous. > Jason -- 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 ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642 _______________________________________________ User-mode-linux-user mailing list User-mode-linux-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-user
