1 files changed, 36 insertions, 16 deletions

diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
index 14afd68664a9..23aefbf6fca5 100644
--- a/drivers/firmware/qcom/qcom_scm.c
+++ b/drivers/firmware/qcom/qcom_scm.c
@@ -217,7 +217,10 @@ static DEFINE_SPINLOCK(scm_query_lock);
 
 struct qcom_tzmem_pool *qcom_scm_get_tzmem_pool(void)
 {
-	return __scm ? __scm->mempool : NULL;
+	if (!qcom_scm_is_available())
+		return NULL;
+
+	return __scm->mempool;
 }
 
 static enum qcom_scm_convention __get_convention(void)
@@ -1839,7 +1842,8 @@ static int qcom_scm_qseecom_init(struct qcom_scm *scm)
  */
 bool qcom_scm_is_available(void)
 {
-	return !!READ_ONCE(__scm);
+	/* Paired with smp_store_release() in qcom_scm_probe */
+	return !!smp_load_acquire(&__scm);
 }
 EXPORT_SYMBOL_GPL(qcom_scm_is_available);
 
@@ -1996,18 +2000,22 @@ static int qcom_scm_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
-	/* Let all above stores be available after this */
+	/* Paired with smp_load_acquire() in qcom_scm_is_available(). */
 	smp_store_release(&__scm, scm);
 
 	irq = platform_get_irq_optional(pdev, 0);
 	if (irq < 0) {
-		if (irq != -ENXIO)
-			return irq;
+		if (irq != -ENXIO) {
+			ret = irq;
+			goto err;
+		}
 	} else {
 		ret = devm_request_threaded_irq(__scm->dev, irq, NULL, qcom_scm_irq_handler,
 						IRQF_ONESHOT, "qcom-scm", __scm);
-		if (ret < 0)
-			return dev_err_probe(scm->dev, ret, "Failed to request qcom-scm irq\n");
+		if (ret < 0) {
+			dev_err_probe(scm->dev, ret, "Failed to request qcom-scm irq\n");
+			goto err;
+		}
 	}
 
 	__get_convention();
@@ -2026,14 +2034,18 @@ static int qcom_scm_probe(struct platform_device *pdev)
 		qcom_scm_disable_sdi();
 
 	ret = of_reserved_mem_device_init(__scm->dev);
-	if (ret && ret != -ENODEV)
-		return dev_err_probe(__scm->dev, ret,
-				     "Failed to setup the reserved memory region for TZ mem\n");
+	if (ret && ret != -ENODEV) {
+		dev_err_probe(__scm->dev, ret,
+			      "Failed to setup the reserved memory region for TZ mem\n");
+		goto err;
+	}
 
 	ret = qcom_tzmem_enable(__scm->dev);
-	if (ret)
-		return dev_err_probe(__scm->dev, ret,
-				     "Failed to enable the TrustZone memory allocator\n");
+	if (ret) {
+		dev_err_probe(__scm->dev, ret,
+			      "Failed to enable the TrustZone memory allocator\n");
+		goto err;
+	}
 
 	memset(&pool_config, 0, sizeof(pool_config));
 	pool_config.initial_size = 0;
@@ -2041,9 +2053,11 @@ static int qcom_scm_probe(struct platform_device *pdev)
 	pool_config.max_size = SZ_256K;
 
 	__scm->mempool = devm_qcom_tzmem_pool_new(__scm->dev, &pool_config);
-	if (IS_ERR(__scm->mempool))
-		return dev_err_probe(__scm->dev, PTR_ERR(__scm->mempool),
-				     "Failed to create the SCM memory pool\n");
+	if (IS_ERR(__scm->mempool)) {
+		ret = dev_err_probe(__scm->dev, PTR_ERR(__scm->mempool),
+				    "Failed to create the SCM memory pool\n");
+		goto err;
+	}
 
 	/*
 	 * Initialize the QSEECOM interface.
@@ -2059,6 +2073,12 @@ static int qcom_scm_probe(struct platform_device *pdev)
 	WARN(ret < 0, "failed to initialize qseecom: %d\n", ret);
 
 	return 0;
+
+err:
+	/* Paired with smp_load_acquire() in qcom_scm_is_available(). */
+	smp_store_release(&__scm, NULL);
+
+	return ret;
 }
 
 static void qcom_scm_shutdown(struct platform_device *pdev)