+/* uint64_t get_unaligned_u64(uint64_t *p);
+ *
+ * Returns the value of the possibly misaligned uint64_t at 'p'. 'p' may
+ * actually be any type that points to a 64-bit integer. That is, on Unix-like
+ * 32-bit ABIs, it may point to an "unsigned long long int", and on Unix-like
+ * 64-bit ABIs, it may point to an "unsigned long int" or an "unsigned long
+ * long int".
+ *
+ * This is special-cased because on some Linux targets, the kernel __u64 is
+ * unsigned long long int and the userspace uint64_t is unsigned long int, so
+ * that any single function prototype would fail to accept one or the other.
+ *
+ * Below, "sizeof (*(P) % 1)" verifies that *P has an integer type, since
+ * operands to % must be integers.
+ */
+#define get_unaligned_u64(P) \
+ (BUILD_ASSERT(sizeof *(P) == 8), \
+ BUILD_ASSERT_GCCONLY(!TYPE_IS_SIGNED(typeof(*(P)))), \
+ (void) sizeof (*(P) % 1), \
+ get_unaligned_u64__((const uint64_t *) (P)))
+