Index: arch/amd64/src/proc/scheduler.c
===================================================================
--- arch/amd64/src/proc/scheduler.c	(revision e515167d463ba945cbb71d0179e971580c6a385c)
+++ arch/amd64/src/proc/scheduler.c	(revision 5c3243e12e8a274e21d3ac2a6ed71c94d4ea19cc)
@@ -32,7 +32,14 @@
 #include <arch.h>
 #include <arch/context.h>	/* SP_DELTA */
+#include <arch/asm.h>
 
 void before_thread_runs_arch(void)
 {
 	CPU->arch.tss->rsp0 = (__address) &THREAD->kstack[THREAD_STACK_SIZE-SP_DELTA];
+
+	/* Syscall support - write thread address to hidden part of gs */
+	swapgs();
+	write_msr(AMD_MSR_GS,
+		  (__u64)&THREAD->kstack);
+	swapgs();
 }