[PATCH v2 07/30] perf pmu: Add from_env parameter to perf_pmu__init()

[Ian Rogers <irogers@google.com>]

Add a boolean from_env field to struct perf_pmu initialized via
perf_pmu__init() to distinguish PMUs reconstructed from perf_env
headers from live host PMUs. Guard tp_pmu, hwmon_pmu, and drm_pmu
callbacks on !pmu->from_env so perf.data-derived PMUs do not access
host tracepoints or cast plain struct perf_pmu allocations via
container_of(). The hwmon and drm evsel open and read callbacks fail
with -EINVAL for such PMUs.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/tests/pmu-events.c |  4 ++--
 tools/perf/util/drm_pmu.c     | 16 ++++++++++----
 tools/perf/util/hwmon_pmu.c   | 16 +++++++++++---
 tools/perf/util/pmu.c         | 41 +++++++++++++++++++----------------
 tools/perf/util/pmu.h         | 13 ++++++++++-
 tools/perf/util/tool_pmu.c    |  2 +-
 6 files changed, 62 insertions(+), 30 deletions(-)

diff --git a/tools/perf/tests/pmu-events.c b/tools/perf/tests/pmu-events.c
index e6e4f4cf1fa2..acf8e8ee1237 100644
--- a/tools/perf/tests/pmu-events.c
+++ b/tools/perf/tests/pmu-events.c
@@ -514,7 +514,7 @@ static int __test_core_pmu_event_aliases(const char *pmu_name, int *count)
 	if (!pmu)
 		return -1;
 
-	if (perf_pmu__init(pmu, PERF_PMU_TYPE_FAKE, pmu_name) != 0) {
+	if (perf_pmu__init(pmu, PERF_PMU_TYPE_FAKE, pmu_name, /*from_env=*/false) != 0) {
 		perf_pmu__delete(pmu);
 		return -1;
 	}
@@ -566,7 +566,7 @@ static int __test_uncore_pmu_event_aliases(struct perf_pmu_test_pmu *test_pmu)
 	if (!pmu)
 		return -1;
 
-	if (perf_pmu__init(pmu, PERF_PMU_TYPE_FAKE, test_pmu->pmu_name) != 0) {
+	if (perf_pmu__init(pmu, PERF_PMU_TYPE_FAKE, test_pmu->pmu_name, /*from_env=*/false) != 0) {
 		perf_pmu__delete(pmu);
 		return -1;
 	}
diff --git a/tools/perf/util/drm_pmu.c b/tools/perf/util/drm_pmu.c
index 5e4bdd8e7fa8..7ef4126ee7e9 100644
--- a/tools/perf/util/drm_pmu.c
+++ b/tools/perf/util/drm_pmu.c
@@ -115,7 +115,7 @@ static struct drm_pmu *add_drm_pmu(struct list_head *pmus, char *line, size_t li
 	if (!drm)
 		return NULL;
 
-	if (perf_pmu__init(&drm->pmu, type, name) != 0) {
+	if (perf_pmu__init(&drm->pmu, type, name, /*from_env=*/false) != 0) {
 		perf_pmu__delete(&drm->pmu);
 		return NULL;
 	}
@@ -515,10 +515,12 @@ int evsel__drm_pmu_open(struct evsel *evsel,
 			struct perf_thread_map *threads,
 			int start_cpu_map_idx, int end_cpu_map_idx)
 {
-	(void)evsel;
 	(void)threads;
 	(void)start_cpu_map_idx;
 	(void)end_cpu_map_idx;
+	/* PMUs reconstructed from a perf.data file can't be opened. */
+	if (!evsel->pmu || evsel->pmu->from_env)
+		return -EINVAL;
 	return 0;
 }
 
@@ -657,11 +659,17 @@ static uint64_t drm_pmu__read_for_pid(struct drm_pmu *drm, struct evsel *evsel,
 
 int evsel__drm_pmu_read(struct evsel *evsel, int cpu_map_idx, int thread)
 {
-	struct drm_pmu *drm = container_of(evsel->pmu, struct drm_pmu, pmu);
+	struct drm_pmu *drm;
 	struct perf_counts_values *count, *old_count = NULL;
-	int pid = perf_thread_map__pid(evsel->core.threads, thread);
+	int pid;
 	uint64_t counter;
 
+	if (!evsel->pmu || evsel->pmu->from_env)
+		return -EINVAL;
+
+	drm = container_of(evsel->pmu, struct drm_pmu, pmu);
+	pid = perf_thread_map__pid(evsel->core.threads, thread);
+
 	if (pid != -1)
 		counter = drm_pmu__read_for_pid(drm, evsel, pid);
 	else
diff --git a/tools/perf/util/hwmon_pmu.c b/tools/perf/util/hwmon_pmu.c
index 96aeb379e169..1526afa37e87 100644
--- a/tools/perf/util/hwmon_pmu.c
+++ b/tools/perf/util/hwmon_pmu.c
@@ -365,7 +365,7 @@ struct perf_pmu *hwmon_pmu__new(struct list_head *pmus, const char *hwmon_dir,
 	if (!hwm)
 		return NULL;
 
-	if (perf_pmu__init(&hwm->pmu, type, buf) != 0) {
+	if (perf_pmu__init(&hwm->pmu, type, buf, /*from_env=*/false) != 0) {
 		perf_pmu__delete(&hwm->pmu);
 		return NULL;
 	}
@@ -763,12 +763,18 @@ int evsel__hwmon_pmu_open(struct evsel *evsel,
 			  struct perf_thread_map *threads,
 			  int start_cpu_map_idx, int end_cpu_map_idx)
 {
-	struct hwmon_pmu *hwm = container_of(evsel->pmu, struct hwmon_pmu, pmu);
+	struct hwmon_pmu *hwm;
 	union hwmon_pmu_event_key key = {
 		.type_and_num = evsel->core.attr.config,
 	};
 	int idx = 0, thread = 0, nthreads, err = 0;
-	int dir = open(hwm->hwmon_dir, O_CLOEXEC | O_DIRECTORY | O_RDONLY);
+	int dir;
+
+	if (!evsel->pmu || evsel->pmu->from_env)
+		return -EINVAL;
+
+	hwm = container_of(evsel->pmu, struct hwmon_pmu, pmu);
+	dir = open(hwm->hwmon_dir, O_CLOEXEC | O_DIRECTORY | O_RDONLY);
 
 	if (dir < 0)
 		return -errno;
@@ -815,6 +821,10 @@ int evsel__hwmon_pmu_read(struct evsel *evsel, int cpu_map_idx, int thread)
 	ssize_t len;
 	struct perf_counts_values *count, *old_count = NULL;
 
+	/* PMUs reconstructed from a perf.data file can't be read. */
+	if (!evsel->pmu || evsel->pmu->from_env)
+		return -EINVAL;
+
 	if (evsel->prev_raw_counts)
 		old_count = perf_counts(evsel->prev_raw_counts, cpu_map_idx, thread);
 
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 01753d5c69d1..531641e66ef4 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -1188,9 +1188,10 @@ static bool aliases__equal(long key1, long key2, void *ctx __maybe_unused)
 	return strcasecmp((const char *)key1, (const char *)key2) == 0;
 }
 
-int perf_pmu__init(struct perf_pmu *pmu, __u32 type, const char *name)
+int perf_pmu__init(struct perf_pmu *pmu, __u32 type, const char *name, bool from_env)
 {
 	pmu->type = type;
+	pmu->from_env = from_env;
 	INIT_LIST_HEAD(&pmu->format);
 	INIT_LIST_HEAD(&pmu->caps);
 
@@ -1240,7 +1241,7 @@ struct perf_pmu *perf_pmu__lookup(struct list_head *pmus, int dirfd, const char
 	if (!pmu)
 		return NULL;
 
-	if (perf_pmu__init(pmu, PERF_PMU_TYPE_FAKE, name) != 0) {
+	if (perf_pmu__init(pmu, PERF_PMU_TYPE_FAKE, name, /*from_env=*/false) != 0) {
 		perf_pmu__delete(pmu);
 		return NULL;
 	}
@@ -1695,9 +1696,9 @@ int perf_pmu__config_terms(const struct perf_pmu *pmu,
 	struct parse_events_term *term;
 
 	if (perf_pmu__is_hwmon(pmu))
-		return hwmon_pmu__config_terms(pmu, attr, terms, err);
+		return pmu->from_env ? -EINVAL : hwmon_pmu__config_terms(pmu, attr, terms, err);
 	if (perf_pmu__is_drm(pmu))
-		return drm_pmu__config_terms(pmu, attr, terms, err);
+		return pmu->from_env ? -EINVAL : drm_pmu__config_terms(pmu, attr, terms, err);
 
 	list_for_each_entry(term, &terms->terms, list) {
 		if (pmu_config_term(pmu, attr, term, terms, zero, apply_hardcoded, err))
@@ -1857,11 +1858,11 @@ int perf_pmu__check_alias(struct perf_pmu *pmu, struct parse_events_terms *head_
 	info->retirement_latency_max = 0.0;
 
 	if (perf_pmu__is_hwmon(pmu)) {
-		ret = hwmon_pmu__check_alias(head_terms, info, err);
+		ret = pmu->from_env ? 0 : hwmon_pmu__check_alias(head_terms, info, err);
 		goto out;
 	}
 	if (perf_pmu__is_drm(pmu)) {
-		ret = drm_pmu__check_alias(pmu, head_terms, info, err);
+		ret = pmu->from_env ? 0 : drm_pmu__check_alias(pmu, head_terms, info, err);
 		goto out;
 	}
 
@@ -2118,11 +2119,11 @@ bool perf_pmu__have_event(struct perf_pmu *pmu, const char *name)
 	if (perf_pmu__is_tool(pmu) && tool_pmu__skip_event(name))
 		return false;
 	if (perf_pmu__is_tracepoint(pmu))
-		return tp_pmu__have_event(pmu, name);
+		return pmu->from_env ? false : tp_pmu__have_event(pmu, name);
 	if (perf_pmu__is_hwmon(pmu))
-		return hwmon_pmu__have_event(pmu, name);
+		return pmu->from_env ? false : hwmon_pmu__have_event(pmu, name);
 	if (perf_pmu__is_drm(pmu))
-		return drm_pmu__have_event(pmu, name);
+		return pmu->from_env ? false : drm_pmu__have_event(pmu, name);
 	if (perf_pmu__find_alias(pmu, name, /*load=*/ true) != NULL)
 		return true;
 	if (pmu->cpu_aliases_added || (!pmu->events_table && !pmu->is_core))
@@ -2139,11 +2140,11 @@ size_t perf_pmu__num_events(struct perf_pmu *pmu)
 	size_t nr;
 
 	if (perf_pmu__is_tracepoint(pmu))
-		return tp_pmu__num_events(pmu);
+		return pmu->from_env ? 0 : tp_pmu__num_events(pmu);
 	if (perf_pmu__is_hwmon(pmu))
-		return hwmon_pmu__num_events(pmu);
+		return pmu->from_env ? 0 : hwmon_pmu__num_events(pmu);
 	if (perf_pmu__is_drm(pmu))
-		return drm_pmu__num_events(pmu);
+		return pmu->from_env ? 0 : drm_pmu__num_events(pmu);
 
 	pmu_aliases_parse(pmu);
 	nr = pmu->sysfs_aliases + pmu->sys_json_aliases;
@@ -2275,11 +2276,11 @@ int perf_pmu__for_each_event(struct perf_pmu *pmu, bool skip_duplicate_pmus,
 	size_t size_rem;
 
 	if (perf_pmu__is_tracepoint(pmu))
-		return tp_pmu__for_each_event(pmu, state, cb);
+		return pmu->from_env ? 0 : tp_pmu__for_each_event(pmu, state, cb);
 	if (perf_pmu__is_hwmon(pmu))
-		return hwmon_pmu__for_each_event(pmu, state, cb);
+		return pmu->from_env ? 0 : hwmon_pmu__for_each_event(pmu, state, cb);
 	if (perf_pmu__is_drm(pmu))
-		return drm_pmu__for_each_event(pmu, state, cb);
+		return pmu->from_env ? 0 : drm_pmu__for_each_event(pmu, state, cb);
 
 	pmu_aliases_parse(pmu);
 	pmu_add_cpu_aliases(pmu);
@@ -2784,10 +2785,12 @@ void perf_pmu__delete(struct perf_pmu *pmu)
 	if (!pmu)
 		return;
 
-	if (perf_pmu__is_hwmon(pmu))
-		hwmon_pmu__exit(pmu);
-	else if (perf_pmu__is_drm(pmu))
-		drm_pmu__exit(pmu);
+	if (!pmu->from_env) {
+		if (perf_pmu__is_hwmon(pmu))
+			hwmon_pmu__exit(pmu);
+		else if (perf_pmu__is_drm(pmu))
+			drm_pmu__exit(pmu);
+	}
 
 	perf_pmu__del_formats(&pmu->format);
 	perf_pmu__del_aliases(pmu);
diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
index 2c8916ad073e..ea55882ce670 100644
--- a/tools/perf/util/pmu.h
+++ b/tools/perf/util/pmu.h
@@ -161,6 +161,8 @@ struct perf_pmu {
 	uint32_t cpu_common_json_aliases;
 	/** @sysfs_aliases_loaded: Are sysfs aliases loaded from disk? */
 	bool sysfs_aliases_loaded;
+	/** @from_env: Was the PMU reconstructed from a perf_env header? */
+	bool from_env;
 	/**
 	 * @cpu_aliases_added: Have all json events table entries for the PMU
 	 * been added?
@@ -345,7 +347,16 @@ int perf_pmu__pathname_scnprintf(char *buf, size_t size,
 int perf_pmu__event_source_devices_fd(void);
 int perf_pmu__pathname_fd(int dirfd, const char *pmu_name, const char *filename, int flags);
 
-int perf_pmu__init(struct perf_pmu *pmu, __u32 type, const char *name);
+/**
+ * perf_pmu__init() - Initialize a pre-allocated struct perf_pmu.
+ * @pmu: The PMU structure to initialize.
+ * @type: The PMU type identifier (PERF_TYPE_* or dynamic sysfs type).
+ * @name: The PMU name string (copied via strdup).
+ * @from_env: True if reconstructed from a perf_env header rather than live sysfs.
+ *
+ * Return: 0 on success, -ENOMEM if duplicating @name fails.
+ */
+int perf_pmu__init(struct perf_pmu *pmu, __u32 type, const char *name, bool from_env);
 struct perf_pmu *perf_pmu__lookup(struct list_head *pmus, int dirfd, const char *lookup_name,
 				  bool eager_load);
 struct perf_pmu *perf_pmu__create_placeholder_core_pmu(struct list_head *core_pmus);
diff --git a/tools/perf/util/tool_pmu.c b/tools/perf/util/tool_pmu.c
index d2f7591747d9..6054d5d5aece 100644
--- a/tools/perf/util/tool_pmu.c
+++ b/tools/perf/util/tool_pmu.c
@@ -714,7 +714,7 @@ struct perf_pmu *tool_pmu__new(void)
 	if (!tool)
 		return NULL;
 
-	if (perf_pmu__init(tool, PERF_PMU_TYPE_TOOL, "tool") != 0) {
+	if (perf_pmu__init(tool, PERF_PMU_TYPE_TOOL, "tool", /*from_env=*/false) != 0) {
 		perf_pmu__delete(tool);
 		return NULL;
 	}
-- 
2.56.1.703.gf848ed807c-goog