Add support for splitting the register windows on entry to the

kernel from usermode.  The remaining user windows are spilled
to the pcb as necessary.  The user land window fault handlers
fill directly from the pcb on return.
Add system call entry points.

Submitted by:	tmm

sys/sparc64/include/frame.h

@@ -71,6 +71,16 @@ struct	frame {
 #define	f_fp	f_in[6]
 #define	f_pc	f_in[7]
 
+/*
+ * Frame used for pcb_wscratch.
+ */
+struct	wsframe {
+	u_long	wsf_local[8];
+	u_long	wsf_in[8];
+	u_long	wsf_sp;
+	u_long	wsf_inuse;
+};
+
 int	kdb_trap(struct trapframe *tf);
 
 #endif /* !_MACHINE_FRAME_H_ */

sys/sparc64/include/pcb.h

@@ -30,14 +30,28 @@
 #define	_MACHINE_PCB_H_
 
 #include <machine/fp.h>
-#include <machine/pstate.h>
+#include <machine/frame.h>
+
+/*
+ * XXX: MAXWIN should probably be done dynamically, pcb_wscratch is therefore
+ * at the end of the pcb.
+ */
+#define	MAXWIN		8
+
+/* Used in pcb_fcwp to mark the wscratch stack as empty. */
+#define	PCB_CWP_EMPTY	0xff
 
 /* NOTE: pcb_fpstate must be aligned on a 64 byte boundary. */
 struct	pcb {
 	struct	fpstate	pcb_fpstate;
 	u_long	pcb_fp;
 	u_long	pcb_pc;
+	u_long	pcb_y;
 	caddr_t	pcb_onfault;
+	u_long	pcb_inwinop;
+	u_long	pcb_cwp;
+	u_long	pcb_ws_inuse;
+	struct	wsframe pcb_wscratch[MAXWIN];
 };
 
 struct	md_coredump {