Intel PT not work on 4.5-rc6 as well after suspend/resume assembler

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Mon, Feb 29, 2016 at 04:25:49PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Mon, Feb 29, 2016 at 06:35:28PM +0100, Andi Kleen escreveu:
> > > What kernel have you used for testing this? 4.5-rc? I'm having trouble
> > > with intel_pt with 4.5.0-rc4 :-\

> > Works for me (on -rc5). What problem do you see?
 
> Doesn't work for me on (4.5.0-rc4), but after your report of it working
> my -rc4 .config and built -rc6+ with it, now it seems to work as
> expected, will test your patch with it later.

Humm, after suspend/resume it is back not working, using your example
for this case:

[root@jouet ~]# uname -a
Linux jouet 4.5.0-rc6+ #1 SMP Mon Feb 29 16:09:29 BRT 2016 x86_64 x86_64 x86_64 GNU/Linux
[root@jouet ~]# perf record -e intel_pt//u true
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.024 MB perf.data ]
[root@jouet ~]# perf script
[root@jouet ~]# perf report -D | tail -20
. ... raw event: size 48 bytes
.  0000:  0f 00 00 00 00 00 30 00 98 03 00 00 98 03 00 00  ......0.........
.  0010:  b6 49 00 00 b6 49 00 00 2c 78 8d 7d 9d 04 00 00  .I...I..,x.}....
.  0020:  03 00 00 00 00 00 00 00 1d 77 1b 00 00 00 00 00  .........w......

3 5074462799916 0x62f0 [0x30]: PERF_RECORD_SWITCH_CPU_WIDE IN   prev pid/tid:   920/920  

Aggregated stats: (excludes AUX area (e.g. instruction trace) decoded / synthesized events)
           TOTAL events:        281
            MMAP events:        124
            COMM events:          2
            EXIT events:          1
           MMAP2 events:          4
    ITRACE_START events:          1
 SWITCH_CPU_WIDE events:        146
  FINISHED_ROUND events:          2
   AUXTRACE_INFO events:          1
intel_pt//u stats:
dummy:u stats:
dummy:u stats:
[root@jouet ~]#

CPU info for this machine:


processor	: 3
vendor_id	: GenuineIntel
cpu family	: 6
model		: 61
model name	: Intel(R) Core(TM) i7-5600U CPU @ 2.60GHz
stepping	: 4
microcode	: 0x22
cpu MHz		: 2759.046
cache size	: 4096 KB
physical id	: 0
siblings	: 4
core id		: 1
cpu cores	: 2
apicid		: 3
initial apicid	: 3
fpu		: yes
fpu_exception	: yes
cpuid level	: 20
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch epb intel_pt tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm rdseed adx smap xsaveopt dtherm ida arat pln pts
bugs		:
bogomips	: 5187.95
clflush size	: 64
cache_alignment	: 64
address sizes	: 39 bits physical, 48 bits virtual
power management:

[root@jouet ~]# 

Trying to reboot the machine to see if it gets back working...

- Arnaldo