Test session cookie for fsession. Multiple fsession BPF progs is attached
to bpf_fentry_test1() and session cookie is read and write in the
testcase.

Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
---
v11:
- add "volatile" to the variable "cookie"

v3:
- restructure the testcase by combine the testcases for session cookie and
  get_func_ip into one patch
---
 .../selftests/bpf/progs/fsession_test.c       | 53 +++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/tools/testing/selftests/bpf/progs/fsession_test.c b/tools/testing/selftests/bpf/progs/fsession_test.c
index f504984d42f2..211332bdcccb 100644
--- a/tools/testing/selftests/bpf/progs/fsession_test.c
+++ b/tools/testing/selftests/bpf/progs/fsession_test.c
@@ -108,3 +108,56 @@ int BPF_PROG(test6, int a)
 		test6_entry_result = (const void *) addr == &bpf_fentry_test1;
 	return 0;
 }
+
+__u64 test7_entry_ok = 0;
+__u64 test7_exit_ok = 0;
+SEC("fsession/bpf_fentry_test1")
+int BPF_PROG(test7, int a)
+{
+	volatile __u64 *cookie = bpf_session_cookie(ctx);
+
+	if (!bpf_session_is_return(ctx)) {
+		*cookie = 0xAAAABBBBCCCCDDDDull;
+		test7_entry_ok = *cookie == 0xAAAABBBBCCCCDDDDull;
+		return 0;
+	}
+
+	test7_exit_ok = *cookie == 0xAAAABBBBCCCCDDDDull;
+	return 0;
+}
+
+__u64 test8_entry_ok = 0;
+__u64 test8_exit_ok = 0;
+
+SEC("fsession/bpf_fentry_test1")
+int BPF_PROG(test8, int a)
+{
+	volatile __u64 *cookie = bpf_session_cookie(ctx);
+
+	if (!bpf_session_is_return(ctx)) {
+		*cookie = 0x1111222233334444ull;
+		test8_entry_ok = *cookie == 0x1111222233334444ull;
+		return 0;
+	}
+
+	test8_exit_ok = *cookie == 0x1111222233334444ull;
+	return 0;
+}
+
+__u64 test9_entry_result = 0;
+__u64 test9_exit_result = 0;
+
+SEC("fsession/bpf_fentry_test1")
+int BPF_PROG(test9, int a, int ret)
+{
+	__u64 *cookie = bpf_session_cookie(ctx);
+
+	if (!bpf_session_is_return(ctx)) {
+		test9_entry_result = a == 1 && ret == 0;
+		*cookie = 0x123456ULL;
+		return 0;
+	}
+
+	test9_exit_result = a == 1 && ret == 2 && *cookie == 0x123456ULL;
+	return 0;
+}
-- 
2.52.0