To NX or not to NX

[Ralf Ertzinger <fedora camperquake de>]

Hi.

Looking through dmesg on my laptop, I noticed the following:

Using x86 segment limits to approximate NX protection

While this is certainly nice, the processor is quite capable of real
NX:

$ grep nx /proc/cpuinfo 
flags           : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx constant_tsc pni monitor vmx est tm2 xtpr
flags           : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx constant_tsc pni monitor vmx est tm2 xtpr

Is there a reason this is not used?

kernel is 2.6.19-1.2891, processor is a Intel Core Duo CPU L2400