11584 ::xcall would be useful
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
Reviewed by: Robert Mustacchi <rm@joyent.com>

*** 20,29 ****
--- 20,30 ----
   */
  
  /*
   * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
+  * Copyright 2018 Joyent, Inc.
   */
  
  #ifndef _SYS_X_CALL_H
  #define _SYS_X_CALL_H
  
*** 31,40 ****
--- 32,49 ----
  extern "C" {
  #endif
  
  #ifndef _ASM
  
+ #define XC_MSG_FREE     (0)     /* msg in xc_free queue */
+ #define XC_MSG_ASYNC    (1)     /* msg in slave xc_msgbox */
+ #define XC_MSG_CALL     (2)     /* msg in slave xc_msgbox */
+ #define XC_MSG_SYNC     (3)     /* msg in slave xc_msgbox */
+ #define XC_MSG_WAITING  (4)     /* msg in master xc_msgbox or xc_waiters */
+ #define XC_MSG_RELEASED (5)     /* msg in slave xc_msgbox */
+ #define XC_MSG_DONE     (6)     /* msg in master xc_msgbox */
+ 
  typedef uintptr_t xc_arg_t;
  typedef int (*xc_func_t)(xc_arg_t, xc_arg_t, xc_arg_t);
  
  /*
   * One of these is stored in each CPU's machcpu data, plus one extra for
*** 50,66 ****
  /*
   * This is kept as small as possible, since for N CPUs we need N * N of them.
   */
  typedef struct xc_msg {
          uint8_t         xc_command;
- #ifdef __amd64
          uint16_t        xc_master;
          uint16_t        xc_slave;
- #else
-         uint8_t         xc_master;
-         uint8_t         xc_slave;
- #endif
          struct xc_msg   *xc_next;
  } xc_msg_t;
  
  /*
   * Cross-call routines.
--- 59,70 ----