interconnect: qcom: Annotate struct icc_onecell_data with __counted_by

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct icc_onecell_data.
Additionally, since the element count member must be set before accessing
the annotated flexible array member, move its initialization earlier.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: Andy Gross <agross@kernel.org>
Cc: Bjorn Andersson <andersson@kernel.org>
Cc: Konrad Dybcio <konrad.dybcio@linaro.org>
Cc: Georgi Djakov <djakov@kernel.org>
Cc: linux-arm-msm@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Acked-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20230817204215.never.916-kees@kernel.org
Signed-off-by: Georgi Djakov <djakov@kernel.org>

Author: kees

drivers/interconnect/qcom/icc-rpmh.c

@@ -185,6 +185,7 @@ int qcom_icc_rpmh_probe(struct platform_device *pdev)
 	data = devm_kzalloc(dev, struct_size(data, nodes, num_nodes), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;
+	data->num_nodes = num_nodes;
 
 	provider = &qp->provider;
 	provider->dev = dev;
@@ -228,8 +229,6 @@ int qcom_icc_rpmh_probe(struct platform_device *pdev)
 		data->nodes[i] = node;
 	}
 
-	data->num_nodes = num_nodes;
-
 	ret = icc_provider_register(provider);
 	if (ret)
 		goto err_remove_nodes;

drivers/interconnect/qcom/msm8974.c

@@ -675,6 +675,7 @@ static int msm8974_icc_probe(struct platform_device *pdev)
 			    GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;
+	data->num_nodes = num_nodes;
 
 	qp->bus_clks = devm_kmemdup(dev, msm8974_icc_bus_clocks,
 				    sizeof(msm8974_icc_bus_clocks), GFP_KERNEL);
@@ -721,7 +722,6 @@ static int msm8974_icc_probe(struct platform_device *pdev)
 
 		data->nodes[i] = node;
 	}
-	data->num_nodes = num_nodes;
 
 	ret = icc_provider_register(provider);
 	if (ret)

drivers/interconnect/qcom/osm-l3.c

@@ -232,6 +232,7 @@ static int qcom_osm_l3_probe(struct platform_device *pdev)
 	data = devm_kzalloc(&pdev->dev, struct_size(data, nodes, num_nodes), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;
+	data->num_nodes = num_nodes;
 
 	provider = &qp->provider;
 	provider->dev = &pdev->dev;
@@ -261,7 +262,6 @@ static int qcom_osm_l3_probe(struct platform_device *pdev)
 
 		data->nodes[i] = node;
 	}
-	data->num_nodes = num_nodes;
 
 	ret = icc_provider_register(provider);
 	if (ret)

include/linux/interconnect-provider.h

@@ -33,7 +33,7 @@ struct icc_node_data {
  */
 struct icc_onecell_data {
 	unsigned int num_nodes;
-	struct icc_node *nodes[];
+	struct icc_node *nodes[] __counted_by(num_nodes);
 };
 
 struct icc_node *of_icc_xlate_onecell(struct of_phandle_args *spec,