perf bpf filter: Add 'pid' sample data support

The pid is special because it's saved in the PERF_SAMPLE_TID together.
So it needs to differenciate tid and pid using the 'part' field in the
perf bpf filter entry struct.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: James Clark <james.clark@arm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Song Liu <song@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230314234237.3008956-2-namhyung@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/bpf-filter.c

@@ -36,6 +36,7 @@ int perf_bpf_filter__prepare(struct evsel *evsel)
 	list_for_each_entry(expr, &evsel->bpf_filters, list) {
 		struct perf_bpf_filter_entry entry = {
 			.op = expr->op,
+			.part = expr->part,
 			.flags = expr->sample_flags,
 			.value = expr->val,
 		};
@@ -76,7 +77,7 @@ u64 perf_bpf_filter__lost_count(struct evsel *evsel)
 	return skel ? skel->bss->dropped : 0;
 }
 
-struct perf_bpf_filter_expr *perf_bpf_filter_expr__new(unsigned long sample_flags,
+struct perf_bpf_filter_expr *perf_bpf_filter_expr__new(unsigned long sample_flags, int part,
 						       enum perf_bpf_filter_op op,
 						       unsigned long val)
 {
@@ -85,6 +86,7 @@ struct perf_bpf_filter_expr *perf_bpf_filter_expr__new(unsigned long sample_flag
 	expr = malloc(sizeof(*expr));
 	if (expr != NULL) {
 		expr->sample_flags = sample_flags;
+		expr->part = part;
 		expr->op = op;
 		expr->val = val;
 	}

tools/perf/util/bpf-filter.h

@@ -9,6 +9,7 @@
 struct perf_bpf_filter_expr {
 	struct list_head list;
 	enum perf_bpf_filter_op op;
+	int part;
 	unsigned long sample_flags;
 	unsigned long val;
 };
@@ -16,7 +17,7 @@ struct perf_bpf_filter_expr {
 struct evsel;
 
 #ifdef HAVE_BPF_SKEL
-struct perf_bpf_filter_expr *perf_bpf_filter_expr__new(unsigned long sample_flags,
+struct perf_bpf_filter_expr *perf_bpf_filter_expr__new(unsigned long sample_flags, int part,
 						       enum perf_bpf_filter_op op,
 						       unsigned long val);
 int perf_bpf_filter__parse(struct list_head *expr_head, const char *str);

tools/perf/util/bpf-filter.l

@@ -11,7 +11,15 @@
 
 static int sample(unsigned long sample_flag)
 {
-	perf_bpf_filter_lval.sample = sample_flag;
+	perf_bpf_filter_lval.sample.type = sample_flag;
+	perf_bpf_filter_lval.sample.part = 0;
+	return BFT_SAMPLE;
+}
+
+static int sample_part(unsigned long sample_flag, int part)
+{
+	perf_bpf_filter_lval.sample.type = sample_flag;
+	perf_bpf_filter_lval.sample.part = part;
 	return BFT_SAMPLE;
 }
 
@@ -56,6 +64,7 @@ ident		[_a-zA-Z][_a-zA-Z0-9]+
 ip		{ return sample(PERF_SAMPLE_IP); }
 id		{ return sample(PERF_SAMPLE_ID); }
 tid		{ return sample(PERF_SAMPLE_TID); }
+pid		{ return sample_part(PERF_SAMPLE_TID, 1); }
 cpu		{ return sample(PERF_SAMPLE_CPU); }
 time		{ return sample(PERF_SAMPLE_TIME); }
 addr		{ return sample(PERF_SAMPLE_ADDR); }

tools/perf/util/bpf-filter.y

@@ -20,7 +20,10 @@ static void perf_bpf_filter_error(struct list_head *expr __maybe_unused,
 %union
 {
 	unsigned long num;
-	unsigned long sample;
+	struct {
+		unsigned long type;
+		int part;
+	} sample;
 	enum perf_bpf_filter_op op;
 	struct perf_bpf_filter_expr *expr;
 }
@@ -48,7 +51,7 @@ filter_term
 filter_term:
 BFT_SAMPLE BFT_OP BFT_NUM
 {
-	$$ = perf_bpf_filter_expr__new($1, $2, $3);
+	$$ = perf_bpf_filter_expr__new($1.type, $1.part, $2, $3);
 }
 
 %%

tools/perf/util/bpf_skel/sample-filter.h

@@ -17,7 +17,8 @@ enum perf_bpf_filter_op {
 /* BPF map entry for filtering */
 struct perf_bpf_filter_entry {
 	enum perf_bpf_filter_op op;
-	__u64 flags;
+	__u32 part; /* sub-sample type info when it has multiple values */
+	__u64 flags; /* perf sample type flags */
 	__u64 value;
 };
 

tools/perf/util/bpf_skel/sample_filter.bpf.c

@@ -40,6 +40,9 @@ static inline __u64 perf_get_sample(struct bpf_perf_event_data_kern *kctx,
 	case PERF_SAMPLE_ID:
 		return kctx->data->id;
 	case PERF_SAMPLE_TID:
+		if (entry->part)
+			return kctx->data->tid_entry.pid;
+		else
 			return kctx->data->tid_entry.tid;
 	case PERF_SAMPLE_CPU:
 		return kctx->data->cpu_entry.cpu;