Index: arch/ia32/src/userspace.c
===================================================================
--- arch/ia32/src/userspace.c	(revision 23684b75fbd877e18cebd073cdb4a435652e8c2c)
+++ arch/ia32/src/userspace.c	(revision a0bb10ef4dc69531a0f1e07ebe00bdbb239dcfef)
@@ -56,4 +56,7 @@
 		"popfl\n"
 
+		/* Set up GS register (TLS) */
+		"movl %6, %%gs\n"
+
 		"pushl %0\n"
 		"pushl %1\n"
@@ -66,5 +69,6 @@
 		: "i" (selector(UDATA_DES) | PL_USER), "r" (kernel_uarg->uspace_stack+THREAD_STACK_SIZE),
 		  "r" (ipl), "i" (selector(UTEXT_DES) | PL_USER), "r" (kernel_uarg->uspace_entry),
-		  "r" (kernel_uarg->uspace_uarg)
+		"r" (kernel_uarg->uspace_uarg),
+		"r" (selector(TLS_DES))
 		: "eax");