[PATCH] efi_loader: Check for the native OP-TEE result on mm_communicate calls

[Ilias Apalodimas]

Currently we only check for the return value of tee_invoke_func().
Although OP-TEE and StMM will correctly set param[1].u.value.a and we'll
eventually return an error, the correct thing to do is check for the
OP_TEE return code as well.
So let's check for that and move tee_shm_free() and tee_close_session()
before exiting with an error to make sure we always clear the registered
memory.

Fixes: f042e47e8fb43 ("efi_loader: Implement EFI variable handling via OP-TEE")
Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
---
 lib/efi_loader/efi_variable_tee.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/efi_loader/efi_variable_tee.c b/lib/efi_loader/efi_variable_tee.c
index c0423489388a..346f4c786f28 100644
--- a/lib/efi_loader/efi_variable_tee.c
+++ b/lib/efi_loader/efi_variable_tee.c
@@ -100,10 +100,10 @@ static efi_status_t optee_mm_communicate(void *comm_buf, ulong dsize)
 	param[1].attr = TEE_PARAM_ATTR_TYPE_VALUE_OUTPUT;
 
 	rc = tee_invoke_func(conn.tee, &arg, 2, param);
-	if (rc)
-		return EFI_INVALID_PARAMETER;
 	tee_shm_free(shm);
 	tee_close_session(conn.tee, conn.session);
+	if (rc || arg.ret != TEE_SUCCESS)
+		return EFI_INVALID_PARAMETER;
 
 	switch (param[1].u.value.a) {
 	case ARM_SMC_MM_RET_SUCCESS:
-- 
2.28.0.rc1