arm64 fix for -rc6

- Fix event counting regression in Arm CMN PMU driver due to broken optimisation
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Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 fix from Will Deacon:

 - Fix event counting regression in Arm CMN PMU driver due to broken
   optimisation

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  Partially revert "perf/arm-cmn: Optimise DTC counter accesses"
This commit is contained in:
Linus Torvalds 2023-01-27 12:56:45 -08:00
commit 0d1e013fd9

View file

@ -1576,7 +1576,6 @@ static int arm_cmn_event_init(struct perf_event *event)
hw->dn++;
continue;
}
hw->dtcs_used |= arm_cmn_node_to_xp(cmn, dn)->dtc;
hw->num_dns++;
if (bynodeid)
break;
@ -1589,6 +1588,12 @@ static int arm_cmn_event_init(struct perf_event *event)
nodeid, nid.x, nid.y, nid.port, nid.dev, type);
return -EINVAL;
}
/*
* Keep assuming non-cycles events count in all DTC domains; turns out
* it's hard to make a worthwhile optimisation around this, short of
* going all-in with domain-local counter allocation as well.
*/
hw->dtcs_used = (1U << cmn->num_dtcs) - 1;
return arm_cmn_validate_group(cmn, event);
}