sysinfo: support basic entries

Change-Id: I27f3e55058cc29f895831a1dddfafbc8585746a5
refs: #1389

kernel/include/rusage_private.h

@@ -56,6 +56,24 @@ rusage_total_memory_add(unsigned long size)
 #endif
 }
 
+static inline unsigned long
+rusage_get_total_memory()
+{
+	return rusage.total_memory;
+}
+
+static inline unsigned long
+rusage_get_free_memory()
+{
+	return rusage.total_memory - rusage.total_memory_usage;
+}
+
+static inline unsigned long
+rusage_get_usage_memory()
+{
+	return rusage.total_memory_usage;
+}
+
 static inline void
 rusage_rss_add(unsigned long size)
 {
@@ -399,6 +417,24 @@ rusage_rss_add(unsigned long size)
 {
 }
 
+static inline unsigned long
+rusage_get_total_memory()
+{
+	return 0;
+}
+
+static inline unsigned long
+rusage_get_free_memory()
+{
+	return 0;
+}
+
+static inline unsigned long
+rusage_get_usage_memory()
+{
+	return 0;
+}
+
 static inline void
 rusage_rss_sub(unsigned long size)
 {