[lttng-dev] ARMv7 Beagle Bone Black and the dmb instruction

[Thibault, Daniel]

   This is a return to an issue first mentioned here in June 2014 ("Debian specific userspace RCU configure override (ARMv7 Beagle Bone Black)").

   I'm trying to install TTng on an ARMv7 Beagle Bone Black.  Lttng-modules "installs" but adds nothing because the kernel has no CONFIG_TRACEPOINTS flag.  So this will be a pure user-space installation.  Userspace-rcu installs without trouble, although I note that its configure log states "checking for dmb instruction... yes".  Lttng-ust, however, fails completely to install.  I note that its configure log makes no mention of a dmb instruction -an omission?

   The make fails at /usr/src/lttng-ust-2.5.0/libringbuffer/libringbuffer_la-ring_buffer_frontend.lo

CC libringbuffer_la-ring_buffer_frontend.lo
/tmp/ccsyYAoj.s: Assembler messages:
/tmp/ccsyYAoj.s:2678: Error: selected processor does not support ARM mode `dmb'
/tmp/ccsyYAoj.s:2692: Error: selected processor does not support ARM mode `dmb'
/tmp/ccsyYAoj.s:2725: Error: selected processor does not support ARM mode `dmb'
...
(22 more such errors)
...
Make[2]: *** [libringbuffer_la-ring_buffer_frontend.lo] Error 1

userspace-rcu is 0.8.0-64-(0.8.4-21)-718eb63
lttng-ust is 2.5.0-10-501f677

'Angstrom GNU/Linux v2012.12 (Core edition)' on kernel '3.8.13'.  No systemtap, no Java or JNI.
Daniel U. Thibault
Protection des systèmes et contremesures (PSC) | Systems Protection & Countermeasures (SPC)
Cyber sécurité pour les missions essentielles (CME) | Mission Critical Cyber Security (MCCS)
RDDC - Centre de recherches de Valcartier | DRDC - Valcartier Research Centre
2459 route de la Bravoure
Québec QC  G3J 1X5
CANADA
Vox : (418) 844-4000 x4245
Fax : (418) 844-4538
NAC : 918V QSDJ <http://www.travelgis.com/map.asp?addr=918V%20QSDJ>
Gouvernement du Canada | Government of Canada
<http://www.valcartier.drdc-rddc.gc.ca/>