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Re: NX bit: AMD vs Intel?



On Fri, 2006-03-31 at 09:36 -0500, fedora-list-request redhat com wrote:

> Date: Fri, 31 Mar 2006 16:35:55 +0200
> From: Jurgen Kramer <gtm kramer inter nl net>
> Subject: Re: NX bit: AMD vs Intel?
> To: gilboad gmail com
> Cc: For users of Fedora Core releases <fedora-list redhat com>
> Message-ID: <1143815755 3328 10 camel paragon slim>
> Content-Type: text/plain
> 
> On Fri, 2006-03-31 at 17:09 +0300, Gilboa Davara wrote:
> > On Fri, 2006-03-31 at 12:56 +0200, 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 ?
> > > 
> > > Both systems run kernel 2.6.16.
> > > 
> > > Jurgen
> > > 
> > 
> > AFAICS, It's activated quietly if present on iAMD64 systems.
> > No printk code.
> > 
> > So, if /proc/cpuinfo includes nx, you're in the clear.
> > 
> Yep, nx is there. Odd that it is only displayed on Intel systems.
> 
> Thanks.
> 
> Jurgen
> 


On my system I get the following:

cat /proc/cpuinfo
processor       : 0
vendor_id       : AuthenticAMD
cpu family      : 15
model           : 4
model name      : AMD Athlon(tm) 64 Processor 2800+
stepping        : 8
cpu MHz         : 800.000
cache size      : 512 KB
fpu             : yes
fpu_exception   : yes
cpuid level     : 1
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx mmxext lm
3dnowext 3dnow lahf_lm
bogomips        : 1730.73
TLB size        : 1024 4K pages
clflush size    : 64
cache_alignment : 64
address sizes   : 40 bits physical, 48 bits virtual
power management: ts fid vid ttp


Notice I see nx in /proc/cpuinfo.

Run this command on your system to see if it shows up...
-- 
ed <ed gurski com>


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