1 files changed, 46 insertions, 3 deletions
diff --git a/src/sys/include/sys/syscall.h b/src/sys/include/sys/syscall.h
index 108f164..e0891e6 100644
--- a/src/sys/include/sys/syscall.h
+++ b/src/sys/include/sys/syscall.h
@@ -31,6 +31,7 @@
 #define _SYS_SYSCALL_H_
 
 #include <sys/types.h>
+#include <sys/limits.h>
 
 /*
  * Syscall numbers
@@ -52,9 +53,51 @@ struct syscall_args {
     struct trapframe *tf;
 };
 
-extern scret_t(*g_sctab[])(struct syscall_args *);
-extern const size_t MAX_SYSCALLS;
+/* Syscall callback */
+typedef scret_t(*sccb_t)(struct syscall_args *);
 
-#endif  /* _KERNEL */
+/*
+ * L5 supports syscall windows in where there can be a
+ * given set of syscalls and whatever syscall traps into
+ * kernel space will address the syscalls referenced by the
+ * current focused window. The window can be slid to change
+ * the type of syscall interface used by the running application.
+ *
+ * @sctab: Syscall table for this window
+ * @nimpl: The number of syscalls implemented
+ * @p: Present bit to indicate usability
+ */
+struct syscall_win {
+    sccb_t *sctab;
+    size_t nimpl;
+    uint8_t p : 1;
+};
+
+/*
+ * Valid platform latch constants
+ */
+typedef enum {
+    SC_PLATCH_UNIX = 0x00,
+    SC_PLATCH_L5,
+    __SC_PLATCH_MAX
+} platch_t;
 
+/*
+ * L5 provides the concept of "syscall domains". A syscall domain
+ * is a collection of syscall windows along with a sliding index
+ * known as the platform latch (`platch') to govern which syscall
+ * interface is to be used.
+ *
+ * @slots: List of windows within this domain
+ * @platch: Platform latch
+ */
+struct syscall_domain {
+    struct syscall_win slots[SCWIN_MAX];
+    platch_t platch;
+};
+
+/* Implemented platforms */
+extern scret_t(*g_unix_sctab[])(struct syscall_args *);
+extern const size_t UNIX_SCTAB_LEN;
+#endif  /* _KERNEL */
 #endif  /* !_SYS_SYSCALL_H_ */