* Move exception_return to exception.s which is a more logical home for it.

* Optimise the return path for syscalls so that they only restore a minimal
  set of registers instead of performing a full exception_return.

A new flag in the trapframe indicates that the frame only holds partial
state. When it is necessary to perform a full state restore (e.g. after an
execve or signal), the flag is cleared to force a full restore.

1 files changed, 6 insertions, 8 deletions

diff --git a/sys/alpha/include/frame.h b/sys/alpha/include/frame.h
index 6d8cceb..7b25696 100644
--- a/sys/alpha/include/frame.h
+++ b/sys/alpha/include/frame.h
@@ -74,18 +74,16 @@
 #define	FRAME_T12		24
 #define	FRAME_AT		25
 #define	FRAME_SP		26
+#define FRAME_FLAGS		27
+#define FRAME_FLAGS_SYSCALL		1 /* partial frame for syscalls */
 /* The following are set only when a signal is to be delivered to a process. */
-#define FRAME_TRAPARG_A0	27
-#define FRAME_TRAPARG_A1	28
-#define FRAME_TRAPARG_A2	29
-/* this is a flag area to see whether we need to restore all registers */
-#define	FRAME_FLAGS		30
+#define FRAME_TRAPARG_A0	28
+#define FRAME_TRAPARG_A1	29
+#define FRAME_TRAPARG_A2	30
 
-#define	FRAME_SW_SIZE	(FRAME_FLAGS + 1)
+#define	FRAME_SW_SIZE	(FRAME_TRAPARG_A2 + 1)
 #define	FRAME_HW_OFFSET	FRAME_SW_SIZE
 
-#define	FRAME_FLAGS_SYSCALL	0x1
-
 #define	FRAME_PS	(FRAME_HW_OFFSET + ALPHA_HWFRAME_PS)
 #define	FRAME_PC	(FRAME_HW_OFFSET + ALPHA_HWFRAME_PC)
 #define	FRAME_GP	(FRAME_HW_OFFSET + ALPHA_HWFRAME_GP)