diff --git a/arch/sparc/include/asm/prom.h b/arch/sparc/include/asm/prom.h
index fd55522481cd9dc0d14a14302446dff9d13017ee..b5efc4d85234445b96ac140557d09ebe854d8437 100644
--- a/arch/sparc/include/asm/prom.h
+++ b/arch/sparc/include/asm/prom.h
@@ -18,6 +18,7 @@
  */
 #include <linux/types.h>
 #include <linux/proc_fs.h>
+#include <linux/mutex.h>
 #include <asm/atomic.h>
 
 #define OF_ROOT_NODE_ADDR_CELLS_DEFAULT	2
@@ -73,6 +74,7 @@ struct of_irq_controller {
 
 extern struct device_node *of_find_node_by_cpuid(int cpuid);
 extern int of_set_property(struct device_node *node, const char *name, void *val, int len);
+extern struct mutex of_set_property_mutex;
 extern int of_getintprop_default(struct device_node *np,
 				 const char *name,
 				 int def);
diff --git a/arch/sparc/kernel/prom.c b/arch/sparc/kernel/prom.c
index cd4fb79aa3a8e185f12d8bfcd8ec90960e2a40ff..43e862406822c299ba3e25d0f28bb539eb646f37 100644
--- a/arch/sparc/kernel/prom.c
+++ b/arch/sparc/kernel/prom.c
@@ -54,6 +54,9 @@ int of_getintprop_default(struct device_node *np, const char *name, int def)
 }
 EXPORT_SYMBOL(of_getintprop_default);
 
+DEFINE_MUTEX(of_set_property_mutex);
+EXPORT_SYMBOL(of_set_property_mutex);
+
 int of_set_property(struct device_node *dp, const char *name, void *val, int len)
 {
 	struct property **prevp;
@@ -77,7 +80,10 @@ int of_set_property(struct device_node *dp, const char *name, void *val, int len
 			void *old_val = prop->value;
 			int ret;
 
+			mutex_lock(&of_set_property_mutex);
 			ret = prom_setprop(dp->node, (char *) name, val, len);
+			mutex_unlock(&of_set_property_mutex);
+
 			err = -EINVAL;
 			if (ret >= 0) {
 				prop->value = new_val;
diff --git a/arch/sparc64/kernel/prom.c b/arch/sparc64/kernel/prom.c
index 3c048ac4e63859394ea7f28c4a75c91daec9df40..922dd612612e14c7693cf6f9fb1ce744c0936482 100644
--- a/arch/sparc64/kernel/prom.c
+++ b/arch/sparc64/kernel/prom.c
@@ -59,6 +59,9 @@ int of_getintprop_default(struct device_node *np, const char *name, int def)
 }
 EXPORT_SYMBOL(of_getintprop_default);
 
+DEFINE_MUTEX(of_set_property_mutex);
+EXPORT_SYMBOL(of_set_property_mutex);
+
 int of_set_property(struct device_node *dp, const char *name, void *val, int len)
 {
 	struct property **prevp;
@@ -82,7 +85,10 @@ int of_set_property(struct device_node *dp, const char *name, void *val, int len
 			void *old_val = prop->value;
 			int ret;
 
+			mutex_lock(&of_set_property_mutex);
 			ret = prom_setprop(dp->node, name, val, len);
+			mutex_unlock(&of_set_property_mutex);
+
 			err = -EINVAL;
 			if (ret >= 0) {
 				prop->value = new_val;