[PATCH RFC 16/20] tools/perf: Pass the Counter constraint values in the pmu events

[Atish Patra]

RISC-V doesn't have any standard event to counter mapping discovery
mechanism in the ISA. The ISA defines 29 programmable counters and
platforms can choose to implement any number of them and map any
events to any counters. Thus, the perf tool need to inform the driver
about the counter mapping of each events.

The current perf infrastructure only parses the 'Counter' constraints
in metrics. This patch extends that to pass in the pmu events so that
any driver can retrieve those values via perf attributes if defined
accordingly.

Signed-off-by: Atish Patra <atishp at rivosinc.com>
---
 tools/perf/pmu-events/jevents.py | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tools/perf/pmu-events/jevents.py b/tools/perf/pmu-events/jevents.py
index 30934a490109..f1e320077695 100755
--- a/tools/perf/pmu-events/jevents.py
+++ b/tools/perf/pmu-events/jevents.py
@@ -278,6 +278,11 @@ class JsonEvent:
         return fixed[name.lower()]
       return event
 
+    def counter_list_to_bitmask(counterlist):
+      counter_ids = list(map(int, counterlist.split(',')))
+      bitmask = sum(1 << pos for pos in counter_ids)
+      return bitmask
+
     def unit_to_pmu(unit: str) -> Optional[str]:
       """Convert a JSON Unit to Linux PMU name."""
       if not unit:
@@ -401,6 +406,10 @@ class JsonEvent:
       else:
         raise argparse.ArgumentTypeError('Cannot find arch std event:', arch_std)
 
+    if self.counter:
+      bitmask = counter_list_to_bitmask(self.counter)
+      event += f',counterid_mask={bitmask:#x}'
+
     self.event = real_event(self.name, event)
 
   def __repr__(self) -> str:
-- 
2.34.1