[ros-dev] Re: [ros-svn] [hbirr] 13102: - Set the limit of the user mode code/data segment back to 4GB.

[Hartmut Birr]

Alex Ionescu schrieb:

> Hi,
>
>>
>> adding the stack segment register to one instruction at the begin of 
>> _KiFastCallEntry does fix the fpu problem for me. 
>
>
>
> That's really great! But how did you come to discover this? i.e, what 
> is the reason for the behavior? I'm glad it's fixed but I would like 
> to understand what's up.
>
I got the fpu crash while compiling ntoskrnl on ros. The dependency 
files were build successful. The crash occurs at the first real 
compilation. I've added many debug prints. I've never seen a fpu trap. 
The crash was a page fault on address 0xffffffff. Eip and an other 
register was 0xffffffff. The return address has point after a fpu 
instruction. I've disabled sysenter and no crash occurs. So I had the 
feeling that something was wrong with the stack, because the address 
0xffffffff is very dirty. Currently I don't understand what is going on. 
Finding the real bug was a little bit try and error.

- Hartmut