3 files changed, 109 insertions, 0 deletions
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index bc7f89948f54..0210f85131b3 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -5164,6 +5164,14 @@ union bpf_attr {
  *		if not NULL, is a reference which must be released using its
  *		corresponding release function, or moved into a BPF map before
  *		program exit.
+ *
+ * void *bpf_map_lookup_percpu_elem(struct bpf_map *map, const void *key, u32 cpu)
+ * 	Description
+ * 		Perform a lookup in *percpu map* for an entry associated to
+ * 		*key* on *cpu*.
+ * 	Return
+ * 		Map value associated to *key* on *cpu*, or **NULL** if no entry
+ * 		was found or *cpu* is invalid.
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -5361,6 +5369,7 @@ union bpf_attr {
 	FN(skb_set_tstamp),		\
 	FN(ima_file_hash),		\
 	FN(kptr_xchg),			\
+	FN(map_lookup_percpu_elem),     \
 	/* */
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
diff --git a/tools/testing/selftests/bpf/prog_tests/map_lookup_percpu_elem.c b/tools/testing/selftests/bpf/prog_tests/map_lookup_percpu_elem.c
new file mode 100644
index 000000000000..58b24c2112b0
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/map_lookup_percpu_elem.c
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2022 Bytedance
+
+#include <test_progs.h>
+
+#include "test_map_lookup_percpu_elem.skel.h"
+
+#define TEST_VALUE  1
+
+void test_map_lookup_percpu_elem(void)
+{
+	struct test_map_lookup_percpu_elem *skel;
+	int key = 0, ret;
+	int nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
+	int *buf;
+
+	buf = (int *)malloc(nr_cpus*sizeof(int));
+	if (!ASSERT_OK_PTR(buf, "malloc"))
+		return;
+	memset(buf, 0, nr_cpus*sizeof(int));
+	buf[0] = TEST_VALUE;
+
+	skel = test_map_lookup_percpu_elem__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "test_map_lookup_percpu_elem__open_and_load"))
+		return;
+	ret = test_map_lookup_percpu_elem__attach(skel);
+	ASSERT_OK(ret, "test_map_lookup_percpu_elem__attach");
+
+	ret = bpf_map_update_elem(bpf_map__fd(skel->maps.percpu_array_map), &key, buf, 0);
+	ASSERT_OK(ret, "percpu_array_map update");
+
+	ret = bpf_map_update_elem(bpf_map__fd(skel->maps.percpu_hash_map), &key, buf, 0);
+	ASSERT_OK(ret, "percpu_hash_map update");
+
+	ret = bpf_map_update_elem(bpf_map__fd(skel->maps.percpu_lru_hash_map), &key, buf, 0);
+	ASSERT_OK(ret, "percpu_lru_hash_map update");
+
+	syscall(__NR_getuid);
+
+	ret = skel->bss->percpu_array_elem_val == TEST_VALUE &&
+	      skel->bss->percpu_hash_elem_val == TEST_VALUE &&
+	      skel->bss->percpu_lru_hash_elem_val == TEST_VALUE;
+	ASSERT_OK(!ret, "bpf_map_lookup_percpu_elem success");
+
+	test_map_lookup_percpu_elem__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_map_lookup_percpu_elem.c b/tools/testing/selftests/bpf/progs/test_map_lookup_percpu_elem.c
new file mode 100644
index 000000000000..5d4ef86cbf48
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_map_lookup_percpu_elem.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2022 Bytedance
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+
+int percpu_array_elem_val = 0;
+int percpu_hash_elem_val = 0;
+int percpu_lru_hash_elem_val = 0;
+
+struct {
+	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+	__uint(max_entries, 1);
+	__type(key, __u32);
+	__type(value, __u32);
+} percpu_array_map SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_PERCPU_HASH);
+	__uint(max_entries, 1);
+	__type(key, __u32);
+	__type(value, __u32);
+} percpu_hash_map SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_LRU_PERCPU_HASH);
+	__uint(max_entries, 1);
+	__type(key, __u32);
+	__type(value, __u32);
+} percpu_lru_hash_map SEC(".maps");
+
+SEC("tp/syscalls/sys_enter_getuid")
+int sysenter_getuid(const void *ctx)
+{
+	__u32 key = 0;
+	__u32 cpu = 0;
+	__u32 *value;
+
+	value = bpf_map_lookup_percpu_elem(&percpu_array_map, &key, cpu);
+	if (value)
+		percpu_array_elem_val = *value;
+
+	value = bpf_map_lookup_percpu_elem(&percpu_hash_map, &key, cpu);
+	if (value)
+		percpu_hash_elem_val = *value;
+
+	value = bpf_map_lookup_percpu_elem(&percpu_lru_hash_map, &key, cpu);
+	if (value)
+		percpu_lru_hash_elem_val = *value;
+
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";