kernel: add per-cpu data section to kernel image

include/socks/percpu.h

@@ -0,0 +1,15 @@
+#ifndef SOCKS_PERCPU_H_
+#define SOCKS_PERCPU_H_
+
+#include <socks/compiler.h>
+
+#define DEFINE_PERCPU_VAR(type, name) \
+	__section(".data.percpu") type name
+
+#define percpu_get(var) __percpu_get(var)
+
+#define percpu_put(var)
+
+extern void *__percpu_get(void *var);
+
+#endif