diff --git a/include/ktls.h b/include/ktls.h
index 7637268b5..942b1118b 100644
--- a/include/ktls.h
+++ b/include/ktls.h
@@ -5,15 +5,21 @@
 
 #ifdef N64_DSO
 __asm__ (
+    ".ifndef __RDHWR_WAS_DEFINED" "\n"
     ".macro rdhwr rt, rd" "\n"
     "   .error \" Usage of thread-local variables is not supported in DSOs. \"" "\n"
     ".endm"               "\n"
+    ".set __RDHWR_WAS_DEFINED, 1" "\n"
+    ".endif" "\n"
 );
 #else
 __asm__ (
+    ".ifndef __RDHWR_WAS_DEFINED" "\n"
     ".macro rdhwr rt, rd" "\n"
     "    lw \\rt, %gprel(th_cur_tp)($gp)" "\n"
     ".endm"               "\n"
+    ".set __RDHWR_WAS_DEFINED, 1" "\n"
+    ".endif" "\n"
 );
 #endif