4 files changed, 52 insertions, 3 deletions
diff --git a/tools/perf/include/bpf/bpf.h b/tools/perf/include/bpf/bpf.h
index 52b6d87fe822..e667577207dc 100644
--- a/tools/perf/include/bpf/bpf.h
+++ b/tools/perf/include/bpf/bpf.h
@@ -18,6 +18,25 @@ struct bpf_map {
         unsigned int numa_node;
 };
 
+/*
+ * FIXME: this should receive .max_entries as a parameter, as careful
+ *	  tuning of these limits is needed to avoid hitting limits that
+ *	  prevents other BPF constructs, such as tracepoint handlers,
+ *	  to get installed, with cryptic messages from libbpf, etc.
+ *	  For the current need, 'perf trace --filter-pids', 64 should
+ *	  be good enough, but this surely needs to be revisited.
+ */
+#define pid_map(name, value_type)		\
+struct bpf_map SEC("maps") name = {		\
+	.type	     = BPF_MAP_TYPE_HASH,	\
+	.key_size    = sizeof(pid_t),		\
+	.value_size  = sizeof(value_type),	\
+	.max_entries = 64,			\
+}
+
+static int (*bpf_map_update_elem)(struct bpf_map *map, void *key, void *value, u64 flags) = (void *)BPF_FUNC_map_update_elem;
+static void *(*bpf_map_lookup_elem)(struct bpf_map *map, void *key) = (void *)BPF_FUNC_map_lookup_elem;
+
 #define SEC(NAME) __attribute__((section(NAME),  used))
 
 #define probe(function, vars) \
@@ -36,4 +55,6 @@ int _version SEC("version") = LINUX_VERSION_CODE;
 static int (*probe_read)(void *dst, int size, const void *unsafe_addr) = (void *)BPF_FUNC_probe_read;
 static int (*probe_read_str)(void *dst, int size, const void *unsafe_addr) = (void *)BPF_FUNC_probe_read_str;
 
+static int (*perf_event_output)(void *, struct bpf_map *, int, void *, unsigned long) = (void *)BPF_FUNC_perf_event_output;
+
 #endif /* _PERF_BPF_H */
diff --git a/tools/perf/include/bpf/pid_filter.h b/tools/perf/include/bpf/pid_filter.h
new file mode 100644
index 000000000000..6e61c4bdf548
--- /dev/null
+++ b/tools/perf/include/bpf/pid_filter.h
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: LGPL-2.1
+
+#ifndef _PERF_BPF_PID_FILTER_
+#define _PERF_BPF_PID_FILTER_
+
+#include <bpf.h>
+
+#define pid_filter(name) pid_map(name, bool)
+
+static int pid_filter__add(struct bpf_map *pids, pid_t pid)
+{
+	bool value = true;
+	return bpf_map_update_elem(pids, &pid, &value, BPF_NOEXIST);
+}
+
+static bool pid_filter__has(struct bpf_map *pids, pid_t pid)
+{
+	return bpf_map_lookup_elem(pids, &pid) != NULL;
+}
+
+#endif // _PERF_BPF_PID_FILTER_
diff --git a/tools/perf/include/bpf/stdio.h b/tools/perf/include/bpf/stdio.h
index 2899cb7bfed8..316af5b2ff35 100644
--- a/tools/perf/include/bpf/stdio.h
+++ b/tools/perf/include/bpf/stdio.h
@@ -9,9 +9,6 @@ struct bpf_map SEC("maps") __bpf_stdout__ = {
        .max_entries = __NR_CPUS__,
 };
 
-static int (*perf_event_output)(void *, struct bpf_map *, int, void *, unsigned long) =
-	(void *)BPF_FUNC_perf_event_output;
-
 #define puts(from) \
 	({ const int __len = sizeof(from); \
 	   char __from[__len] = from; \
diff --git a/tools/perf/include/bpf/unistd.h b/tools/perf/include/bpf/unistd.h
new file mode 100644
index 000000000000..ca7877f9a976
--- /dev/null
+++ b/tools/perf/include/bpf/unistd.h
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: LGPL-2.1
+
+#include <bpf.h>
+
+static int (*bpf_get_current_pid_tgid)(void) = (void *)BPF_FUNC_get_current_pid_tgid;
+
+static pid_t getpid(void)
+{
+	return bpf_get_current_pid_tgid();
+}