1 files changed, 46 insertions, 0 deletions

diff --git a/include/linux/bitfield.h b/include/linux/bitfield.h
index 1030651f8309..cf2588d81148 100644
--- a/include/linux/bitfield.h
+++ b/include/linux/bitfield.h
@@ -16,6 +16,7 @@
 #define _LINUX_BITFIELD_H
 
 #include <linux/build_bug.h>
+#include <asm/byteorder.h>
 
 /*
  * Bitfield access macros
@@ -103,4 +104,49 @@
                 (typeof(_mask))(((_reg) & (_mask)) >> __bf_shf(_mask)); \
         })
 
+extern void __compiletime_warning("value doesn't fit into mask")
+__field_overflow(void);
+extern void __compiletime_error("bad bitfield mask")
+__bad_mask(void);
+static __always_inline u64 field_multiplier(u64 field)
+{
+        if ((field | (field - 1)) & ((field | (field - 1)) + 1))
+                __bad_mask();
+        return field & -field;
+}
+static __always_inline u64 field_mask(u64 field)
+{
+        return field / field_multiplier(field);
+}
+#define ____MAKE_OP(type,base,to,from)                                  \
+static __always_inline __##type type##_encode_bits(base v, base field)  \
+{                                                                       \
+        if (__builtin_constant_p(v) &&  (v & ~field_multiplier(field))) \
+                            __field_overflow();                         \
+        return to((v & field_mask(field)) * field_multiplier(field));   \
+}                                                                       \
+static __always_inline __##type type##_replace_bits(__##type old,       \
+                                        base val, base field)           \
+{                                                                       \
+        return (old & ~to(field)) | type##_encode_bits(val, field);     \
+}                                                                       \
+static __always_inline void type##p_replace_bits(__##type *p,           \
+                                        base val, base field)           \
+{                                                                       \
+        *p = (*p & ~to(field)) | type##_encode_bits(val, field);        \
+}                                                                       \
+static __always_inline base type##_get_bits(__##type v, base field)     \
+{                                                                       \
+        return (from(v) & field)/field_multiplier(field);               \
+}
+#define __MAKE_OP(size)                                                 \
+        ____MAKE_OP(le##size,u##size,cpu_to_le##size,le##size##_to_cpu) \
+        ____MAKE_OP(be##size,u##size,cpu_to_be##size,be##size##_to_cpu) \
+        ____MAKE_OP(u##size,u##size,,)
+__MAKE_OP(16)
+__MAKE_OP(32)
+__MAKE_OP(64)
+#undef __MAKE_OP
+#undef ____MAKE_OP
+
 #endif