Re: cpuctl panic(!)

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

On Thu, Jul 24, 2014 at 11:36:43PM +0100, Patrick Welche wrote:
> 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!

It seems to be fixed: this looks like the same cpu, and no core dump
on Tuesday's -current:

# 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), 2492.01 MHz
cpu0: family 0x6 model 0x2a stepping 0x7 (id 0x206a7)
cpu0: features 0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE>
cpu0: features 0xbfebfbff<MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2>
cpu0: features 0xbfebfbff<SS,HTT,TM,SBF>
cpu0: features1 0x1fbae3ff<SSE3,PCLMULQDQ,DTES64,MONITOR,DS-CPL,VMX,SMX,EST>
cpu0: features1 0x1fbae3ff<TM2,SSSE3,CX16,xTPR,PDCM,PCID,SSE41,SSE42,X2APIC>
cpu0: features1 0x1fbae3ff<POPCNT,DEADLINE,AES,XSAVE,OSXSAVE,AVX>
cpu0: features2 0x28100800<SYSCALL/SYSRET,XD,RDTSCP,EM64T>
cpu0: features3 0x1<LAHF>
cpu0: xsave features 0x7<x87,SSE,AVX>
cpu0: xsave instructions 0x1<XSAVEOPT>
cpu0: xsave area size: current 832, maximum 832, xgetbv enabled
cpu0: enabled xsave 0x7<x87,SSE,AVX>
cpu0: I-cache 32KB 64B/line 8-way, D-cache 32KB 64B/line 8-way
cpu0: L2 cache 256KB 64B/line 8-way
cpu0: L3 cache 3MB 64B/line 12-way
cpu0: 64B prefetching
cpu0: ITLB 64 4KB entries 4-way, 2M/4M: 8 entries
cpu0: DTLB 64 4KB entries 4-way, 2M/4M: 32 entries (L0)
cpu0: L2 STLB 512 4KB entries 4-way
cpu0: Initial APIC ID 0
cpu0: Cluster/Package ID 0
cpu0: Core ID 0
cpu0: SMT ID 0
cpu0: DSPM-eax 0x77<DTS,IDA,ARAT,PLN,CME,PLTM>
cpu0: DSPM-ecx 0x9<HWF,EPB>
cpu0: SEF highest subleaf 00000000
cpu0: microcode version 0x23, platform ID 4

Cheers,

Patrick