Jurgen Kramer wrote:
On my Intel system (Xeon with EMT64 support) which runs the 32-bit
version of FC5 I can see that NX support is active (from dmesg):
NX (Execute Disable) protection: active
On my other system, a AMD64 system running the 64-bit version of FC4,
there is no message regarding NX support being enabled of disabled at
all.
Checking init.c in the kernel sources it seems that NX support is
depended on PAE support and NX support from the processor. As the AMD
processor supports both I aspect to see a NX procection active message
on my AMD system as well. Does NX support suppose to work on 64-bit
kernels ?
[james@kendrick linux-2.6.16.1]$ grep -R "NX (Execute Disable) protection" .
./arch/i386/mm/init.c: printk("NX (Execute Disable) protection:
active\n");
So you don't see the message on x86-64 because it's only actually
present in i386 code. This might be because there's a huge amount of
i386-compatible computers that *don't* support NX. It's always been
there on AMD64 (and apparently on *nearly* all Intel EM64T processors:
http://www.theregister.co.uk/2004/07/30/intel_nocona_nx/ ).
I'm not sure how Linux handles the Noconas without XD (Intel's name for
it). But I understand NX is always on when it's there.
Hope this helps,
James.
--
E-mail address: james | Legacy (adj):
@westexe.demon.co.uk | an uncomplimentary computer-industry epithet that
| means 'it works'.
| -- Anthony DeBoer