NX bit disabled?

[rkagan]

I'm fighting with a strange issue:

Atom N280 supports a feature known as NX bit (or XD - eXecute Disable in Intel speak). This feature allows protecting certain RAM pages from executing code stored in them, and are an important part of the OS security mechanisms.

However, my CPU doesn't report this feature as supported (through CPUID instruction level 0x80000001).

I was suspecting a BIOS bug, and reported the issue to Lenovo IdeaPad support channel. However, after about 4 weeks of communication, they were unable to reproduce the problem in their test lab, claiming that NX bit worked correctly in all OSes they tried (DOS, Windows, Linux).

They assumed a problem with the mainboard, and suggested getting the notebook to a service center.

Before I do, I'd like to check if I'm really unique with this problem.

Can anybody with a similar computer please spend a bit of his time and bandwidth and check if his system reports NX bit as supported?

This can be done with e.g. one of

* CPU-Z: http://www.cpuid.com/cpuz.php

* chkcpu: http://web.inter.nl.net/hcc/J.Steunebrink/chkcpu.htm

For the record, my system is S10-2, model no. 20027, BIOS 1ACN21WW (but the problem was there with 20 and 14 too).

TIA

[rkagan]

Here's what I get from chkcpu:

Code: Select all

# chkcpu32.exe /v

CPU Identification utility v2.05                 (c) 1997-2009 Jan Steunebrink
──────────────────────────────────────────────────────────────────────────────
CPU Vendor and Model: Intel Atom 230/N270/Z500/Z510/Z515/Z520-Z550 C0-step
Internal CPU speed  : 1662.5 MHz
System CPU count    : 1 Physical CPU(s), 1 Core(s) per CPU, 1 Thread(s)
CPU-ID Vendor string: GenuineIntel
CPU-ID Name string  : Intel(R) Atom(TM) CPU N280   @ 1.66GHz
CPU-ID Signature    : 0106C2
CPU Features        : Floating-Point Unit on chip  : Yes
                       Time Stamp Counter           : Yes
                       Enhanced SpeedStep Technology: Yes
                       Hyper-Threading Technology   : Yes
                       Execute Disable protection   : No
                       64-bit support               : No
                       Virtualization Technology    : No
Instr set extensions: MMX, SSE, SSE2, SSE3, SSSE3
Size of L1 cache    : 32 KB
Integrated L2 cache : 512 KB
Integrated L3 cache : None


Code: Select all

# chkcpu32.exe /d

CPU Identification utility v2.05                 (c) 1997-2009 Jan Steunebrink
──────────────────────────────────────────────────────────────────────────────
                                 Debug Mode!
Windows version     : 5.1.2600  ;
Basetimer frequency : 3579545 Hz

     CPUID Level:   EAX:           EBX:           ECX:           EDX:
       00000000       0000000A       756E6547       6C65746E      49656E69
       00000001       000106C2       00020800       0040C39D      BFE9FBFF
       00000002       4FBA5901       0E3080C0       00000000      00000000
       00000003       00000000       00000000       00000000      00000000
       00000004       00004121       0140003F       0000003F      00000001
       00000004       00004122       01C0003F       0000003F      00000001
       00000004       00004143       01C0003F       000003FF      00000001
       00000005       00000040       00000040       00000003      00020220
       00000006       00000001       00000002       00000001      00000000

       80000000       80000008       00000000       00000000      00000000
       80000001       00000000       00000000       00000001      00000000
       80000002       20202020       20202020       746E4920      52286C65
       80000003       74412029       54286D6F       4320294D      4E205550
       80000004       20303832       20402020       36362E31      007A4847
       80000005       00000000       00000000       00000000      00000000
       80000006       00000000       00000000       02008040      00000000
       80000007       00000000       00000000       00000000      00000000
       80000008       00002020       00000000       00000000      00000000


[mister2]

I've never heard of NX bit prior to your post. For kicks and giggles, I ran CHKCPU32 on my S10 with N270 processor. The Execute Disable protection does come up with "Yes" on my S10 so I'm not sure what may be the problem with your S10-2.

[rkagan]

The problem turned out to be in the BIOS. Details at
http://forums.lenovo.com/t5/IdeaPad-S-series-Netbooks/s10-2-no-NX-bit/m-p/176962#M5941