+/*
+ * Tricky points:
+ * - Use __builtin_choose_expr to avoid type promotion from ?:,
+ * - Invalid sizes result in a compile time error stemming from
+ * the fact that abort has no parameters.
+ * - It's easier to use the endian-specific unaligned load/store
+ * functions than host-endian unaligned load/store plus tswapN.
+ * - The pragmas are necessary only to silence a clang false-positive
+ * warning: see https://bugs.llvm.org/show_bug.cgi?id=39113 .
+ * - gcc has bugs in its _Pragma() support in some versions, eg
+ * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83256 -- so we only
+ * include the warning-suppression pragmas for clang
+ */
+#if defined(__clang__) && __has_warning("-Waddress-of-packed-member")
+#define PRAGMA_DISABLE_PACKED_WARNING \
+ _Pragma("GCC diagnostic push"); \
+ _Pragma("GCC diagnostic ignored \"-Waddress-of-packed-member\"")
+
+#define PRAGMA_REENABLE_PACKED_WARNING \
+ _Pragma("GCC diagnostic pop")
+
+#else
+#define PRAGMA_DISABLE_PACKED_WARNING
+#define PRAGMA_REENABLE_PACKED_WARNING
+#endif
+
+#define __put_user_e(x, hptr, e) \
+ do { \
+ PRAGMA_DISABLE_PACKED_WARNING; \
+ (__builtin_choose_expr(sizeof(*(hptr)) == 1, stb_p, \
+ __builtin_choose_expr(sizeof(*(hptr)) == 2, stw_##e##_p, \
+ __builtin_choose_expr(sizeof(*(hptr)) == 4, stl_##e##_p, \
+ __builtin_choose_expr(sizeof(*(hptr)) == 8, stq_##e##_p, abort)))) \
+ ((hptr), (x)), (void)0); \
+ PRAGMA_REENABLE_PACKED_WARNING; \
+ } while (0)
+
+#define __get_user_e(x, hptr, e) \
+ do { \
+ PRAGMA_DISABLE_PACKED_WARNING; \
+ ((x) = (typeof(*hptr))( \
+ __builtin_choose_expr(sizeof(*(hptr)) == 1, ldub_p, \
+ __builtin_choose_expr(sizeof(*(hptr)) == 2, lduw_##e##_p, \
+ __builtin_choose_expr(sizeof(*(hptr)) == 4, ldl_##e##_p, \
+ __builtin_choose_expr(sizeof(*(hptr)) == 8, ldq_##e##_p, abort)))) \
+ (hptr)), (void)0); \
+ PRAGMA_REENABLE_PACKED_WARNING; \
+ } while (0)
+
+
+#if TARGET_BIG_ENDIAN
+# define __put_user(x, hptr) __put_user_e(x, hptr, be)
+# define __get_user(x, hptr) __get_user_e(x, hptr, be)
+#else
+# define __put_user(x, hptr) __put_user_e(x, hptr, le)
+# define __get_user(x, hptr) __get_user_e(x, hptr, le)
+#endif