Split the test into two subtests: one for checking bpf_probe_read* of a
vsyscall page from a non-sleepable probe and one for checking
bpf_copy_from_user* of a vsyscall page from a sleepable probe.

The split is useful for running the test on kernels which do not support
sleepable fentry programs to allow skipping just a part of the test.

Signed-off-by: Viktor Malik <vmalik@redhat.com>
---
 .../selftests/bpf/prog_tests/read_vsyscall.c  | 41 ++++++++++++++++---
 .../selftests/bpf/progs/read_vsyscall.c       | 18 ++++----
 2 files changed, 44 insertions(+), 15 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/read_vsyscall.c b/tools/testing/selftests/bpf/prog_tests/read_vsyscall.c
index a8d1eaa67020..bbacd1309046 100644
--- a/tools/testing/selftests/bpf/prog_tests/read_vsyscall.c
+++ b/tools/testing/selftests/bpf/prog_tests/read_vsyscall.c
@@ -14,22 +14,30 @@
 struct read_ret_desc {
 	const char *name;
 	int ret;
-} all_read[] = {
+};
+
+struct read_ret_desc all_probe_read[] = {
 	{ .name = "probe_read_kernel", .ret = -ERANGE },
 	{ .name = "probe_read_kernel_str", .ret = -ERANGE },
 	{ .name = "probe_read", .ret = -ERANGE },
 	{ .name = "probe_read_str", .ret = -ERANGE },
 	{ .name = "probe_read_user", .ret = -EFAULT },
 	{ .name = "probe_read_user_str", .ret = -EFAULT },
+};
+
+struct read_ret_desc all_copy_from_user[] = {
 	{ .name = "copy_from_user", .ret = -EFAULT },
 	{ .name = "copy_from_user_task", .ret = -EFAULT },
 	{ .name = "copy_from_user_str", .ret = -EFAULT },
 	{ .name = "copy_from_user_task_str", .ret = -EFAULT },
 };
 
-void test_read_vsyscall(void)
+static void test_read_vsyscall_subtest(const char *prog_name,
+				       const struct read_ret_desc *descs,
+				       unsigned int cnt)
 {
 	struct read_vsyscall *skel;
+	struct bpf_program *prog;
 	unsigned int i;
 	int err;
 
@@ -37,10 +45,19 @@ void test_read_vsyscall(void)
 	test__skip();
 	return;
 #endif
-	skel = read_vsyscall__open_and_load();
-	if (!ASSERT_OK_PTR(skel, "read_vsyscall open_load"))
+	skel = read_vsyscall__open();
+	if (!ASSERT_OK_PTR(skel, "read_vsyscall open"))
 		return;
 
+	prog = bpf_object__find_program_by_name(skel->obj, prog_name);
+	if (!ASSERT_OK_PTR(prog, "read_vsyscall find program"))
+		goto out;
+	bpf_program__set_autoload(prog, true);
+
+	err = read_vsyscall__load(skel);
+	if (!ASSERT_EQ(err, 0, "read_vsyscall load"))
+		goto out;
+
 	skel->bss->target_pid = getpid();
 	err = read_vsyscall__attach(skel);
 	if (!ASSERT_EQ(err, 0, "read_vsyscall attach"))
@@ -52,8 +69,20 @@ void test_read_vsyscall(void)
 	skel->bss->user_ptr = (void *)VSYSCALL_ADDR;
 	usleep(1);
 
-	for (i = 0; i < ARRAY_SIZE(all_read); i++)
-		ASSERT_EQ(skel->bss->read_ret[i], all_read[i].ret, all_read[i].name);
+	for (i = 0; i < cnt; i++)
+		ASSERT_EQ(skel->bss->read_ret[i], descs[i].ret, descs[i].name);
 out:
 	read_vsyscall__destroy(skel);
 }
+
+void test_read_vsyscall(void)
+{
+	if (test__start_subtest("probe_read")) {
+		test_read_vsyscall_subtest("probe_read", all_probe_read,
+					   ARRAY_SIZE(all_probe_read));
+	}
+	if (test__start_subtest("copy_from_user")) {
+		test_read_vsyscall_subtest("copy_from_user", all_copy_from_user,
+					   ARRAY_SIZE(all_copy_from_user));
+	}
+}
diff --git a/tools/testing/selftests/bpf/progs/read_vsyscall.c b/tools/testing/selftests/bpf/progs/read_vsyscall.c
index 395591374d4f..45bcf923ec70 100644
--- a/tools/testing/selftests/bpf/progs/read_vsyscall.c
+++ b/tools/testing/selftests/bpf/progs/read_vsyscall.c
@@ -8,7 +8,7 @@
 
 int target_pid = 0;
 void *user_ptr = 0;
-int read_ret[10];
+int read_ret[6];
 
 char _license[] SEC("license") = "GPL";
 
@@ -19,8 +19,8 @@ int bpf_copy_from_user_str(void *dst, u32, const void *, u64) __weak __ksym;
 int bpf_copy_from_user_task_str(void *dst, u32, const void *,
 				struct task_struct *, u64) __weak __ksym;
 
-SEC("fentry/" SYS_PREFIX "sys_nanosleep")
-int do_probe_read(void *ctx)
+SEC("?fentry/" SYS_PREFIX "sys_nanosleep")
+int probe_read(void *ctx)
 {
 	char buf[8];
 
@@ -37,19 +37,19 @@ int do_probe_read(void *ctx)
 	return 0;
 }
 
-SEC("fentry.s/" SYS_PREFIX "sys_nanosleep")
-int do_copy_from_user(void *ctx)
+SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep")
+int copy_from_user(void *ctx)
 {
 	char buf[8];
 
 	if ((bpf_get_current_pid_tgid() >> 32) != target_pid)
 		return 0;
 
-	read_ret[6] = bpf_copy_from_user(buf, sizeof(buf), user_ptr);
-	read_ret[7] = bpf_copy_from_user_task(buf, sizeof(buf), user_ptr,
+	read_ret[0] = bpf_copy_from_user(buf, sizeof(buf), user_ptr);
+	read_ret[1] = bpf_copy_from_user_task(buf, sizeof(buf), user_ptr,
 					      bpf_get_current_task_btf(), 0);
-	read_ret[8] = bpf_copy_from_user_str((char *)buf, sizeof(buf), user_ptr, 0);
-	read_ret[9] = bpf_copy_from_user_task_str((char *)buf,
+	read_ret[2] = bpf_copy_from_user_str((char *)buf, sizeof(buf), user_ptr, 0);
+	read_ret[3] = bpf_copy_from_user_task_str((char *)buf,
 						  sizeof(buf),
 						  user_ptr,
 						  bpf_get_current_task_btf(),
-- 
2.53.0