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-rw-r--r--include/uapi/linux/const.h24
1 files changed, 24 insertions, 0 deletions
diff --git a/include/uapi/linux/const.h b/include/uapi/linux/const.h
new file mode 100644
index 000000000000..c22c707c455d
--- /dev/null
+++ b/include/uapi/linux/const.h
@@ -0,0 +1,24 @@
+/* const.h: Macros for dealing with constants. */
+
+#ifndef _LINUX_CONST_H
+#define _LINUX_CONST_H
+
+/* Some constant macros are used in both assembler and
+ * C code. Therefore we cannot annotate them always with
+ * 'UL' and other type specifiers unilaterally. We
+ * use the following macros to deal with this.
+ *
+ * Similarly, _AT() will cast an expression with a type in C, but
+ * leave it unchanged in asm.
+ */
+
+#ifdef __ASSEMBLY__
+#define _AC(X,Y) X
+#define _AT(T,X) X
+#else
+#define __AC(X,Y) (X##Y)
+#define _AC(X,Y) __AC(X,Y)
+#define _AT(T,X) ((T)(X))
+#endif
+
+#endif /* !(_LINUX_CONST_H) */