diff --git a/arch/x86_64/start_64.S b/arch/x86_64/start_64.S
index 57d0720..e0d00dd 100644
--- a/arch/x86_64/start_64.S
+++ b/arch/x86_64/start_64.S
@@ -7,6 +7,9 @@
 .global start_64
 .type start_64, @function
 start_64:
+	/* convert %rsp to a higher-half pointer */
+	add $0xFFFFFFFF80000000, %rsp
+
 	pop %rdi
 	call kernel_init