Messages in this thread | | | Subject | Re: [Fastboot] [CFT] kexec syscall for 2.5.43 (linux booting linux) | From | (Eric W. Biederman) | Date | 22 Oct 2002 10:02:03 -0600 |
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ebiederm@xmission.com (Eric W. Biederman) writes:
> Rob Landley <landley@trommello.org> writes: > > > On Tuesday 22 October 2002 03:33, Eric W. Biederman wrote: > > > > > j < Printed from the second callback in setup.S, just before the > > > kernel decompresser is run > > > > > > > > > > I have a very strange node that makes it all of the way to 'j' before > > > rebooting. The concept that something is dying in protected mode will all > > > of the interrupts disabled is so novel that I really don't know what to > > > make of it, yet. > > > > It would almost have to be the MMU. Any way to dump the page tables? > > I don't know yet. I need to find a way to install some additional hooks > at run time so I can narrow down where the failure is occuring. I > will have to look, but I should be able to set up an interrupt > descriptor table and single step through the code.
In the process of setting up hooks, I have run across a very interesting data point. If I load %ds, %es, %ss in my hook the problem goes away. But I must load all 3.
Given that the code sequence that is executed if my hook is not run is:
cld cli movl $(__KERNEL_DS),%eax movl %eax,%ds movl %eax,%es movl %eax,%fs movl %eax,%gs
lss stack_start,%esp
I am rather confused. I am not changing the gdt or anything like that so it appears I may have found a way to tickle a processor errata.
Anyway Andy if you have a second please try kexec-tools 1.3 and see what happens when you pass it the debug option. I am really curious if your lockup is anywhere near mine. I doubt it as I am running on a P4. But it appears you never know what the problems will look like until you test them.
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