1 files changed, 66 insertions, 0 deletions
diff --git a/include/linux/align.h b/include/linux/align.h
new file mode 100644
index 000000000000..68bad1ac089f
--- /dev/null
+++ b/include/linux/align.h
@@ -0,0 +1,66 @@
+#ifndef _LINUX_ALIGN_H
+#define _LINUX_ALIGN_H
+
+#define __ALIGN_KERNEL(x, a)	__ALIGN_KERNEL_MASK(x, (typeof(x))(a) - 1)
+#define __ALIGN_KERNEL_MASK(x, mask) \
+				(((x) + (mask)) & ~(mask))
+
+#ifdef __KERNEL__
+
+#include <linux/types.h>
+
+#define ALIGN(x, a)		__ALIGN_KERNEL(x, a)
+#define __ALIGN_MASK(x, mask)	__ALIGN_KERNEL_MASK(x, mask)
+#define PTR_ALIGN(p, a)		((typeof(p)) ALIGN((unsigned long) (p), a))
+#define ALIGN_FLOOR(x, a)	__ALIGN_FLOOR_MASK(x, (typeof(x)) (a) - 1)
+#define __ALIGN_FLOOR_MASK(x, mask)	((x) & ~(mask))
+#define PTR_ALIGN_FLOOR(p, a) \
+			((typeof(p)) ALIGN_FLOOR((unsigned long) (p), a))
+#define IS_ALIGNED(x, a)	(((x) & ((typeof(x)) (a) - 1)) == 0)
+
+/*
+ * Align pointer on natural object alignment.
+ */
+#define object_align(obj)	PTR_ALIGN(obj, __alignof__(*(obj)))
+#define object_align_floor(obj)	PTR_ALIGN_FLOOR(obj, __alignof__(*(obj)))
+
+#define MAYBE_BUILD_BUG_ON(condition)           \
+do {                                            \
+        if (__builtin_constant_p(condition))    \
+                BUILD_BUG_ON(condition);        \
+} while (0)
+
+/**
+ * offset_align - Calculate the offset needed to align an object on its natural
+ *                alignment towards higher addresses.
+ * @align_drift:  object offset from an "alignment"-aligned address.
+ * @alignment:    natural object alignment. Must be non-zero, power of 2.
+ *
+ * Returns the offset that must be added to align towards higher
+ * addresses.
+ */
+#define offset_align(align_drift, alignment)				       \
+	({								       \
+		MAYBE_BUILD_BUG_ON((alignment) == 0			       \
+				   || ((alignment) & ((alignment) - 1)));      \
+		(((alignment) - (align_drift)) & ((alignment) - 1));	       \
+	})
+
+/**
+ * offset_align_floor - Calculate the offset needed to align an object
+ *                      on its natural alignment towards lower addresses.
+ * @align_drift:  object offset from an "alignment"-aligned address.
+ * @alignment:    natural object alignment. Must be non-zero, power of 2.
+ *
+ * Returns the offset that must be substracted to align towards lower addresses.
+ */
+#define offset_align_floor(align_drift, alignment)			       \
+	({								       \
+		MAYBE_BUILD_BUG_ON((alignment) == 0			       \
+				   || ((alignment) & ((alignment) - 1)));      \
+		(((align_drift) - (alignment)) & ((alignment) - 1);	       \
+	})
+
+#endif /* __KERNEL__ */
+
+#endif