[Bugme-new] [Bug 4426] New: /proc/cpuinfo reports PNI support on Athlon and Athlon-XP

[bugme-daemon at osdl.org]

http://bugme.osdl.org/show_bug.cgi?id=4426

           Summary: /proc/cpuinfo reports PNI support on Athlon and Athlon-
                    XP
    Kernel Version: >=2.6.10
            Status: NEW
          Severity: normal
             Owner: platform_i386 at kernel-bugs.osdl.org
         Submitter: liverbugg at Juno.com


Distribution: Gentoo
Hardware Environment: AMD Athlon Thunderbird and AMD Athlon-XP Barton
Software Environment: 

Problem Description:
cat /proc/cpuinfo is reporting pni(Prescott New Instructions or SSE3) support on
my Athlon and Athlon-XP chips.  This instruction set was added with the P4
Prescott and Opteron x52.

kernel-2.6.11-r3
processor       : 0
vendor_id       : AuthenticAMD
cpu family      : 6
model           : 10
model name      : AMD Athlon(tm) XP
stepping        : 0
cpu MHz         : 2204.807
cache size      : 512 KB
physical id     : 0
siblings        : 1
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
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 mmx fxsr sse pni syscall mmxext 3dnowext 3dnow
bogomips        : 4358.14

kernel-2.6.10-r4 and kernel-2.6.11-r4
processor       : 0
vendor_id       : AuthenticAMD
cpu family      : 6
model           : 4
model name      : AMD Athlon(tm) processor
stepping        : 2
cpu MHz         : 850.662
cache size      : 256 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 1
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 sep mtrr pge mca cmov pat
pse36 mmx fxsr pni syscall mmxext 3dnowext 3dnow
bogomips        : 1667.07

The Athlon-XP dual boots WinXP and CPU-Z correctly reports no PNI support.

A different Athlon-XP box is running 2.6.7-r14 and it correctly reports no PNI.

I tested stock kernel.org kernels 2.6.7 through 2.6.12-rc1-mm3 and 2.6.10 and up
have this behaviour.

Steps to reproduce:
cat /proc/cpuinfo

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