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| author | Robin Murphy <robin.murphy@arm.com> | 2022-12-05 19:46:13 +0000 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2023-01-19 18:30:21 +0000 |
| commit | bb21ef19a3d8f586a99310116d40622fb5b79942 (patch) | |
| tree | 60c274adf7220640a62bd13c1d12d66ed8789437 /drivers | |
| parent | e126f6f42f89baee09e088ab6bc48f83ac3a0eae (diff) | |
| download | linux-stable-bb21ef19a3d8f586a99310116d40622fb5b79942.tar.gz linux-stable-bb21ef19a3d8f586a99310116d40622fb5b79942.tar.bz2 linux-stable-bb21ef19a3d8f586a99310116d40622fb5b79942.zip | |
perf/arm-cmn: Reset DTM_PMU_CONFIG at probe
Although we treat the DTM counters as free-running such that we're not
too concerned about the initial DTM state, it's possible for a previous
user to have left DTM counters enabled and paired with DTC counters.
Thus if the first events are scheduled using some, but not all, DTMs,
the as-yet-unused ones could end up adding spurious increments to the
event counts at the DTC. Make sure we sync our initial DTM_PMU_CONFIG
state to all the DTMs at probe time to avoid that possibility.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/ba5f38b3dc733cd06bfb5e659b697e76d18c2183.1670269572.git.robin.murphy@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/perf/arm-cmn.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c index b80a9b74662b..e220714954b0 100644 --- a/drivers/perf/arm-cmn.c +++ b/drivers/perf/arm-cmn.c @@ -1865,6 +1865,7 @@ static void arm_cmn_init_dtm(struct arm_cmn_dtm *dtm, struct arm_cmn_node *xp, i dtm->base = xp->pmu_base + CMN_DTM_OFFSET(idx); dtm->pmu_config_low = CMN_DTM_PMU_CONFIG_PMU_EN; + writeq_relaxed(dtm->pmu_config_low, dtm->base + CMN_DTM_PMU_CONFIG); for (i = 0; i < 4; i++) { dtm->wp_event[i] = -1; writeq_relaxed(0, dtm->base + CMN_DTM_WPn_MASK(i)); |