kernel: add header files

include/kernel/compiler.h

@@ -0,0 +1,41 @@
+#ifndef KERNEL_COMPILER_H_
+#define KERNEL_COMPILER_H_
+
+#ifdef __cplusplus
+template <typename T>
+T read_once(const volatile T *ptr)
+{
+	return *ptr;
+}
+
+template <typename T>
+void write_once(volatile T *ptr, T value)
+{
+	*ptr = value;
+}
+#else
+
+#define READ_ONCE(p) (*((const volatile typeof(p) *)&(p)))
+#define WRITE_ONCE(p, v) *(volatile typeof(p) *)&(p) = (v)
+
+#endif
+
+#undef __used
+#define __used __attribute__((__used__))
+
+#undef __noreturn
+#define __noreturn __attribute__((__noreturn__))
+
+#undef __packed
+#define __packed __attribute__((__packed__))
+
+#undef __section
+#define __section(name) __attribute__((__section__(name)))
+
+#undef __aligned
+#define __aligned(x) __attribute__((__aligned__(x)))
+
+#undef __weak
+#define __weak __attribute__((__weak__))
+
+#endif