firmware: qcom: uefisecapp: fix efivars registration race

Since the conversion to using the TZ allocator, the efivars service is
registered before the memory pool has been allocated, something which
can lead to a NULL-pointer dereference in case of a racing EFI variable
access.

Make sure that all resources have been set up before registering the
efivars.

Fixes: 6612103ec35a ("firmware: qcom: qseecom: convert to using the TZ allocator")
Cc: [e-mail] # 6.11
Cc: Bartosz Golaszewski <[e-mail]>
Signed-off-by: Johan Hovold <[e-mail]>
Reviewed-by: Konrad Dybcio <[e-mail]>
Reviewed-by: Maximilian Luz <[e-mail]>
Reviewed-by: Bartosz Golaszewski <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Bjorn Andersson <[e-mail]>

drivers/firmware/qcom/qcom_qseecom_uefisecapp.c

···
 
 	qcuefi->client = container_of(aux_dev, struct qseecom_client, aux_dev);
 
-	auxiliary_set_drvdata(aux_dev, qcuefi);
-	status = qcuefi_set_reference(qcuefi);
-	if (status)
-		return status;
-
-	status = efivars_register(&qcuefi->efivars, &qcom_efivar_ops);
-	if (status)
-		qcuefi_set_reference(NULL);
-
 	memset(&pool_config, 0, sizeof(pool_config));
 	pool_config.initial_size = SZ_4K;
 	pool_config.policy = QCOM_TZMEM_POLICY_MULTIPLIER;
···
 	qcuefi->mempool = devm_qcom_tzmem_pool_new(&aux_dev->dev, &pool_config);
 	if (IS_ERR(qcuefi->mempool))
 		return PTR_ERR(qcuefi->mempool);
+
+	auxiliary_set_drvdata(aux_dev, qcuefi);
+	status = qcuefi_set_reference(qcuefi);
+	if (status)
+		return status;
+
+	status = efivars_register(&qcuefi->efivars, &qcom_efivar_ops);
+	if (status)
+		qcuefi_set_reference(NULL);
 
 	return status;
 }