Add convenience APIs pmc_width() and pmc_capabilities() to -lpmc.

Have pmcstat(8) and pmccontrol(8) use these APIs.

Return PMC class-related constants (PMC widths and capabilities)
with the OP GETCPUINFO call leaving OP PMCINFO to return only the
dynamic information associated with a PMC (i.e., whether enabled,
owner pid, reload count etc.).

Allow pmc_read() (i.e., OPS PMCRW) on active self-attached PMCs to
get upto-date values from hardware since we can guarantee that the
hardware is running the correct PMC at the time of the call.

Bug fixes:
 - (x86 class processors) Fix a bug that prevented an RDPMC
   instruction from being recognized as permitted till after the
   attached process had context switched out and back in again after
   a pmc_start() call.

   Tighten the rules for using RDPMC class instructions: a GETMSR
   OP is now allowed only after an OP ATTACH has been done by the
   PMC's owner to itself.  OP GETMSR is not allowed for PMCs that
   track descendants, for PMCs attached to processes other than
   their owner processes.

 - (P4/HTT processors only) Fix a bug that caused the MI and MD
   layers to get out of sync.  Add a new MD operation 'get_config()'
   as part of this fix.

 - Allow multiple system-mode PMCs at the same row-index but on
   different CPUs to be allocated.

 - Reject allocation of an administratively disabled PMC.

Misc. code cleanups and refactoring.  Improve a few comments.

1 files changed, 2 insertions, 0 deletions

diff --git a/lib/libpmc/pmc.h b/lib/libpmc/pmc.h
index 98c4af2..7ee257b 100644
--- a/lib/libpmc/pmc.h
+++ b/lib/libpmc/pmc.h
@@ -38,6 +38,7 @@
 int	pmc_allocate(const char *_ctrspec, enum pmc_mode _mode, uint32_t _flags,
     int _cpu, pmc_id_t *_pmcid);
 int	pmc_attach(pmc_id_t _pmcid, pid_t _pid);
+int	pmc_capabilities(pmc_id_t _pmc, uint32_t *_caps);
 int	pmc_configure_logfile(int _fd);
 int	pmc_detach(pmc_id_t _pmcid, pid_t _pid);
 int	pmc_disable(int _cpu, int _pmc);
@@ -50,6 +51,7 @@ int	pmc_rw(pmc_id_t _pmc, pmc_value_t _newvalue, pmc_value_t *_oldvalue);
 int	pmc_set(pmc_id_t _pmc, pmc_value_t _value);
 int	pmc_start(pmc_id_t _pmc);
 int	pmc_stop(pmc_id_t _pmc);
+int	pmc_width(pmc_id_t _pmc, uint32_t *_width);
 int	pmc_write(pmc_id_t _pmc, pmc_value_t _value);
 
 int	pmc_ncpu(void);