[PATCH] perf jevents: Raise exception for no definition of a arch std event

[John Garry <john.g.garry@oracle.com>]

Recently Ilkka reported that the JSONs for the AmpereOne arm64-based
platform included a dud event which referenced a non-existent arch std
event [0].

Previously in the times of jevents.c, we would raise an exception for this.

This is still invalid, even though the current code just ignores such an
event.

Re-introduce code to raise an exception for when no definition exists to
help catch as many invalid JSONs as possible.

[0] https://lore.kernel.org/linux-perf-users/9e851e2a-26c7-ba78-cb20-be4337b2916a@oracle.com/

Signed-off-by: John Garry <john.g.garry@oracle.com>
---
Please do not apply before [0], above.

diff --git a/tools/perf/pmu-events/jevents.py b/tools/perf/pmu-events/jevents.py
index 8cd561aa606a..98cccc3fcbbd 100755
--- a/tools/perf/pmu-events/jevents.py
+++ b/tools/perf/pmu-events/jevents.py
@@ -347,12 +347,15 @@ class JsonEvent:
       if self.desc and not self.desc.endswith('. '):
         self.desc += '. '
       self.desc = (self.desc if self.desc else '') + ('Unit: ' + self.pmu + ' ')
-    if arch_std and arch_std.lower() in _arch_std_events:
-      event = _arch_std_events[arch_std.lower()].event
-      # Copy from the architecture standard event to self for undefined fields.
-      for attr, value in _arch_std_events[arch_std.lower()].__dict__.items():
-        if hasattr(self, attr) and not getattr(self, attr):
-          setattr(self, attr, value)
+    if arch_std:
+      if arch_std.lower() in _arch_std_events:
+        event = _arch_std_events[arch_std.lower()].event
+        # Copy from the architecture standard event to self for undefined fields.
+        for attr, value in _arch_std_events[arch_std.lower()].__dict__.items():
+          if hasattr(self, attr) and not getattr(self, attr):
+            setattr(self, attr, value)
+      else:
+        raise argparse.ArgumentTypeError('Cannot find arch std event:', arch_std)
 
     self.event = real_event(self.name, event)
 
-- 
2.35.3