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authorRobin Murphy <robin.murphy@arm.com>2021-01-28 16:12:43 +0300
committerWill Deacon <will@kernel.org>2021-01-28 23:14:45 +0300
commit79d7c3dca99fa96033695ddf5d495b775a3a137b (patch)
treea543bd5a56936035ee368dd337505c4b2b7d7069
parentf0c140481d1b807217cacdcf11d24cfa407a7a53 (diff)
downloadlinux-79d7c3dca99fa96033695ddf5d495b775a3a137b.tar.xz
perf/arm-cmn: Fix PMU instance naming
Although it's neat to avoid the suffix for the typical case of a single PMU, it means systems with multiple CMN instances end up with inconsistent naming. I think it also breaks perf tool's "uncore alias" logic if the common instance prefix is also the full name of one. Avoid any surprises by not trying to be clever and simply numbering every instance, even when it might technically prove redundant. Fixes: 0ba64770a2f2 ("perf: Add Arm CMN-600 PMU driver") Signed-off-by: Robin Murphy <robin.murphy@arm.com> Link: https://lore.kernel.org/r/649a2281233f193d59240b13ed91b57337c77b32.1611839564.git.robin.murphy@arm.com Signed-off-by: Will Deacon <will@kernel.org>
-rw-r--r--Documentation/admin-guide/perf/arm-cmn.rst2
-rw-r--r--drivers/perf/arm-cmn.c13
2 files changed, 5 insertions, 10 deletions
diff --git a/Documentation/admin-guide/perf/arm-cmn.rst b/Documentation/admin-guide/perf/arm-cmn.rst
index 0e4809346014..796e25b7027b 100644
--- a/Documentation/admin-guide/perf/arm-cmn.rst
+++ b/Documentation/admin-guide/perf/arm-cmn.rst
@@ -17,7 +17,7 @@ PMU events
----------
The PMU driver registers a single PMU device for the whole interconnect,
-see /sys/bus/event_source/devices/arm_cmn. Multi-chip systems may link
+see /sys/bus/event_source/devices/arm_cmn_0. Multi-chip systems may link
more than one CMN together via external CCIX links - in this situation,
each mesh counts its own events entirely independently, and additional
PMU devices will be named arm_cmn_{1..n}.
diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c
index f30fcd330899..6bdf13f65875 100644
--- a/drivers/perf/arm-cmn.c
+++ b/drivers/perf/arm-cmn.c
@@ -1502,7 +1502,7 @@ static int arm_cmn_probe(struct platform_device *pdev)
struct arm_cmn *cmn;
const char *name;
static atomic_t id;
- int err, rootnode, this_id;
+ int err, rootnode;
cmn = devm_kzalloc(&pdev->dev, sizeof(*cmn), GFP_KERNEL);
if (!cmn)
@@ -1549,14 +1549,9 @@ static int arm_cmn_probe(struct platform_device *pdev)
.cancel_txn = arm_cmn_end_txn,
};
- this_id = atomic_fetch_inc(&id);
- if (this_id == 0) {
- name = "arm_cmn";
- } else {
- name = devm_kasprintf(cmn->dev, GFP_KERNEL, "arm_cmn_%d", this_id);
- if (!name)
- return -ENOMEM;
- }
+ name = devm_kasprintf(cmn->dev, GFP_KERNEL, "arm_cmn_%d", atomic_fetch_inc(&id));
+ if (!name)
+ return -ENOMEM;
err = cpuhp_state_add_instance(arm_cmn_hp_state, &cmn->cpuhp_node);
if (err)