Re: x86 CPU detection code in 2.1.75 and later kernels

Shaw Carruthers (
Tue, 23 Dec 1997 11:42:35 +0000 (GMT)

On Tue, 23 Dec 1997, Andre Derrick Balsa wrote:

> 1) The new code reports all x86 family 5 processors (e.g. Cyrix 6x86 and
> AMD K6) as having the f0 bug. We all know that the latest elegant f0 bug
> workaround has zero penalty and so is enabled regardless of the
> processor (good - this makes kernel code shorter and simpler). But it
> looks funny in /proc/cpuinfo and may confuse owners of 6x86 and K6 CPUs.
> On the other hand, if I had an Intel Pentium CPU, I'd prefer to get the
> bug correctly reported, as well as seeing that the workaround is
> enabled.
> 8) The AMD K6 bug in early CPUs is not detected or reported, even though
> the necessary code for this detection has been sent to the list (by
> Benoit Poulot).

? Processor is an early K6-166, so dmesg output seems correst

Linux version 2.1.75 (root@shawc) (gcc version #3 Mon Dec 22 17:14:46 GMT 1997
CPU: AMD AMD-K6tm w/ multimedia extensions stepping 01
Checking 386/387 coupling... Ok, fpu using exception 16 error reporting.
Checking 'hlt' instruction... Ok.
AMD K6 stepping B detected - <6>K6 BUG 21012173 20000000 (Report these if test report is incorrect)
AMD K6 stepping B detected - <6>system stability may be impaired when more than 32 MB are used.
Please see

and /proc/cpuinfo

processor : 0
cpu family : 5
model : AMD-K6tm w/ multimedia extensions
vendor_id : AuthenticAMD
stepping : 1
fdiv_bug : no
hlt_bug : no
sep_bug : no
f00f_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 1
wp : yes
flags : fpu vme de pse tsc msr mce cx8 mmx
bogomips : 332.60

Shaw Carruthers -
London SW14 7JW UK
This is not a sig( with homage to Magritte).