diff --git a/src/thread/mips/__unmapself.s b/src/thread/mips/__unmapself.s
index 9aa03712bda91d3ff837742925bf9ad1f6d3fbf8..ba139dc8e7ba8d8672c1261c9391ca9da0f70524 100644
--- a/src/thread/mips/__unmapself.s
+++ b/src/thread/mips/__unmapself.s
@@ -2,6 +2,7 @@
 .global __unmapself
 .type   __unmapself,@function
 __unmapself:
+	move $sp, $25
 	li $2, 4091
 	syscall
 	li $4, 0