selftests/bpf: add test case for bpf_map_lookup_percpu_elem

test_progs:
Tests new ebpf helpers bpf_map_lookup_percpu_elem.
Signed-off-by: Feng Zhou <zhoufeng.zf@bytedance.com>
Link: https://lore.kernel.org/r/20220511093854.411-3-zhoufeng.zf@bytedance.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/prog_tests/map_lookup_percpu_elem.c

+// 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);
+}

tools/testing/selftests/bpf/progs/test_map_lookup_percpu_elem.c

+// 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";