Re: cpuctl panic(!)

[Patrick Welche <prlw1%cam.ac.uk@localhost>]

On Thu, Jul 24, 2014 at 11:21:29PM +0100, David Laight wrote:
> On Wed, Jun 18, 2014 at 12:43:57PM +0100, Patrick Welche wrote:
> > Surprise (-current/amd64):
> > 
> > # cpuctl identify 0
> > cpu0: highest basic info 0000000d
> > cpu0: highest extended info 80000008
> > cpu0: "Intel(R) Core(TM) i5-2520M CPU @ 2.50GHz"
> > cpu0: Intel Xeon E3-12xx, 2nd gen i7, i5, i3 2xxx (686-class), 2492.10 MHz
> > cpu0: family 0x6 model 0x2a stepping 0x7 (id 0x206a7)
> > ...
> > cpu0: xsave features 0x7<x87,SSE,AVX>
> > cpu0: xsave instructions 0x1<XSAVEOPT>
> > cpu0: xsave area size: current 832, maximum 832, xgetbv enabled
> > [1]   Segmentation fault (core dumped) cpuctl identify 0
> > 
> > Program terminated with signal 11, Segmentation fault.
> > #0  0x00000000004053d0 in x86_xgetbv ()
> > (gdb) bt
> > #0  0x00000000004053d0 in x86_xgetbv ()
> > #1  0x000000000040467d in identifycpu (fd=3, cpuname=0x7f7fffffdb30 "cpu0")
> >     at /usr/src/usr.sbin/cpuctl/arch/i386.c:1824
> > #2  0x0000000000401cd0 in cpu_identify (argv=0x7f7fffffdbd8)
> >     at /usr/src/usr.sbin/cpuctl/cpuctl.c:277
> > #3  0x0000000000401644 in main (argc=2, argv=0x7f7fffffdbd0)
> >     at /usr/src/usr.sbin/cpuctl/cpuctl.c:116
> 
> The cpu features indicate that xgetbv is available, but when it is executes
> there cpu faults.
> Clearly that shouldn't happen.
> IIRC qemu is buggy - is that bare metal?

It was bare metal - I need to remember which piece of metal though!

Cheers,

Patrick