diff --git a/arch/x86_64/freestanding/bits.h b/arch/x86_64/freestanding/bits.h
new file mode 100644
index 0000000..7a5e00e
--- /dev/null
+++ b/arch/x86_64/freestanding/bits.h
@@ -0,0 +1,62 @@
+#ifndef LIBUCONTEXT_BITS_H
+#define LIBUCONTEXT_BITS_H
+
+#define REG_R8		(0)
+#define REG_R9 		(1)
+#define REG_R10 	(2)
+#define REG_R11		(3)
+#define REG_R12		(4)
+#define REG_R13		(5)
+#define REG_R14		(6)
+#define REG_R15		(7)
+#define REG_RDI		(8)
+#define REG_RSI		(9)
+#define REG_RBP		(10)
+#define REG_RBX		(11)
+#define REG_RDX		(12)
+#define REG_RAX		(13)
+#define REG_RCX		(14)
+#define REG_RSP		(15)
+#define REG_RIP		(16)
+#define REG_EFL		(17)
+#define REG_CSGSFS	(18)
+#define REG_ERR		(19)
+#define REG_TRAPNO	(20)
+#define REG_OLDMASK	(21)
+#define REG_CR2		(22)
+
+typedef long long libucontext_greg_t, libucontext_gregset_t[23];
+
+typedef struct libucontext_fpstate {
+	unsigned short cwd, swd, ftw, fop;
+	unsigned long long rip, rdp;
+	unsigned mxcsr, mxcr_mask;
+	struct {
+		unsigned short significand[4], exponent, padding[3];
+	} _st[8];
+	struct {
+		unsigned element[4];
+	} _xmm[16];
+	unsigned padding[24];
+} *libucontext_fpregset_t;
+
+typedef struct {
+	libucontext_gregset_t gregs;
+	libucontext_fpregset_t fpregs;
+	unsigned long long __reserved1[8];
+} libucontext_mcontext_t;
+
+typedef struct {
+	void *ss_sp;
+	int ss_flags;
+	size_t ss_size;
+} libucontext_stack_t;
+
+typedef struct libucontext_ucontext {
+	unsigned long uc_flags;
+	struct libucontext_ucontext *uc_link;
+	libucontext_stack_t uc_stack;
+	libucontext_mcontext_t uc_mcontext;
+} libucontext_ucontext_t;
+
+#endif
diff --git a/arch/x86_64/makecontext.c b/arch/x86_64/makecontext.c
index a1e3e2d..0550ff6 100644
--- a/arch/x86_64/makecontext.c
+++ b/arch/x86_64/makecontext.c
@@ -22,7 +22,7 @@ extern void libucontext_trampoline(void);
 
 
 void
-libucontext_makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
+libucontext_makecontext(libucontext_ucontext_t *ucp, void (*func)(void), int argc, ...)
 {
 	libucontext_greg_t *sp;
 	va_list va;