Intel platform specific

NTDEV
1

Hi All,

This is about Windows on intel platform

I was thinking GDTR is loaded only once per windows session, at the
startup. And LDTR will be loaded everytime a process context switch takes
place. Is this correct?

In a multi processor system all the GDTRs will be loaded with the same
value through out a windows session right? I mean GDT is system specific
and not processor or process specific right?

Please clarify

Thanks
Arun

2

> I was thinking GDTR is loaded only once per windows session, at the

startup.

Once per CPU :slight_smile: it is loaded on CPU initialization and is never
updated.

And LDTR will be loaded everytime a process context switch takes
place.

Yes, but for NTVDM processes only. NTVDM is the only process in NT
which uses LDT, the 32bit processes do not.

In a multi processor system all the GDTRs will be loaded with the
same
value through out a windows session right? I mean GDT is system
specific

No, it is per-CPU, since the user-mode FS selector references the
current thread, which is different on different CPUs.

Max