Index: uspace/lib/libc/arch/amd64/include/fibril.h
===================================================================
--- uspace/lib/libc/arch/amd64/include/fibril.h	(revision e15e0e8bcc3e3f28628a17ecc49ae0d7e5c356f8)
+++ uspace/lib/libc/arch/amd64/include/fibril.h	(revision 50286ec7df341653f61a11ea4895db0e82307e46)
@@ -44,4 +44,12 @@
 #define SP_DELTA     16
 
+#define context_set(c, _pc, stack, size, ptls) \
+	do { \
+		(c)->pc = (sysarg_t) (_pc); \
+		(c)->sp = ((sysarg_t) (stack)) + (size) - SP_DELTA; \
+		(c)->tls = (sysarg_t) (ptls); \
+		(c)->rbp = 0; \
+	} while (0)
+
 /* We include only registers that must be preserved
  * during function call