On Fri, Mar 08, 2013 at 10:02:31PM -0600, Nathan Fontenot wrote:

This patch adds a platform_has_feature() function to check features selected
by firmware and reported via the device tree 'ibm,architecture-vec5'
property. As part of this the #defines used for the architecture vector are
moved to prom.h and re-defined such that the vector 5 options have the vector
index and the feature bits encoded into them. This allows for callers of
platform_has_feature() to pass in a single pre-defined value.

One other comment...

+#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV)
+bool platform_has_feature(unsigned int feature)
+{
+	struct device_node *chosen;
+	const char *vec5;
+	bool has_option;
+
+	chosen = of_find_node_by_path("/chosen");
+	if (!chosen)
+		return false;
+
+	vec5 = of_get_property(chosen, "ibm,architecture-vec-5", NULL);
+	has_option = vec5 && (vec5[OV5_INDX(feature)] & OV5_FEAT(feature));

You access vec5[index] without checking that the vector is at least
index+1 bytes long, according to either the length byte at the
beginning of the vector, or the total length of the property.
Checking both would be a good idea.

Paul.