diff --git a/proc.c b/proc.c
index 6829b4608a54fddabe36a8804db64063bec8f0e6..91a58010c603e4b07092420c978ae9d3acb4d61b 100644
--- a/proc.c
+++ b/proc.c
@@ -75,6 +75,7 @@ ksegment(void)
   loadfsgs(SEG_KCPU << 3);
   
   // Initialize cpu-local variables.
+  c->tlsstruct = &c->tlsstruct;
   cpu = c;
   proc = 0;
 }
diff --git a/proc.h b/proc.h
index c099dbf152fdfcb74d7ed5e1180d047452edce66..10760f826f1018783925f6f8a2fbf5218e432a58 100644
--- a/proc.h
+++ b/proc.h
@@ -59,6 +59,7 @@ struct cpu {
   int ncli;                    // Depth of pushcli nesting.
   int intena;                  // Were interrupts enabled before pushcli?
   void *tls[2];
+  void *tlsstruct;
 };
 
 extern struct cpu cpus[NCPU];