[PATCH for_v37 6/6] selftests/sgx: Add a smoke test to ensure the user handler is invoked

[Sean Christopherson <sean.j.christopherson@intel.com>]

Add a very simple exit handler and use it as a third variant of the SGX
selftest to verify that the vDSO invokes then user's handler when one is
supplied.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 tools/testing/selftests/sgx/main.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/tools/testing/selftests/sgx/main.c b/tools/testing/selftests/sgx/main.c
index 158ea9e2b6d3a..44acb3c720675 100644
--- a/tools/testing/selftests/sgx/main.c
+++ b/tools/testing/selftests/sgx/main.c
@@ -137,10 +137,21 @@ int check_result(struct sgx_enclave_run *run, int ret, uint64_t result,
 		printf("FAIL: %s(), expected: 0x%lx, got: 0x%lx\n",
 		       test, MAGIC, result);
 		return -EIO;
+	} else if (run->user_data) {
+		printf("FAIL: %s() user data, expected: 0x0, got: 0x%llx\n",
+		       test, run->user_data);
+		return -EIO;
 	}
 	return 0;
 }
 
+static int exit_handler(long rdi, long rsi, long rdx, long ursp, long r8, long r9,
+			struct sgx_enclave_run *run)
+{
+	run->user_data = 0;
+	return 0;
+}
+
 int main(int argc, char *argv[], char *envp[])
 {
 	struct sgx_enclave_run run;
@@ -203,6 +214,14 @@ int main(int argc, char *argv[], char *envp[])
 	if (check_result(&run, ret, result, "eenter"))
 		goto err;
 
+	/* And with an exit handler. */
+	run.user_handler = exit_handler;
+	run.user_data = 0xdeadbeef;
+	ret = eenter((unsigned long)&MAGIC, (unsigned long)&result, 0, EENTER,
+		     0, 0, &run);
+	if (check_result(&run, ret, result, "exit_handler"))
+		goto err;
+
 	printf("SUCCESS\n");
 	encl_delete(&encl);
 	exit(0);
-- 
2.28.0