FreeBSD/Linux Kernel Cross Reference
sys/norma/ipc_wait.c

     /* 
      * Mach Operating System
      * Copyright (c) 1991 Carnegie Mellon University
      * All Rights Reserved.
      * 
      * Permission to use, copy, modify and distribute this software and its
      * documentation is hereby granted, provided that both the copyright
      * notice and this permission notice appear in all copies of the
      * software, derivative works or modified versions, and any portions
     * thereof, and that both notices appear in supporting documentation.
     * 
     * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
     * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
     * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     * 
     * Carnegie Mellon requests users of this software to return to
     * 
     *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
     *  School of Computer Science
     *  Carnegie Mellon University
     *  Pittsburgh PA 15213-3890
     * 
     * any improvements or extensions that they make and grant Carnegie Mellon
     * the rights to redistribute these changes.
     */
    /*
     * HISTORY
     * $Log:        ipc_wait.c,v $
     * Revision 2.8  92/03/10  16:28:37  jsb
     *      Merged in norma branch changes as of NORMA_MK7.
     *      [92/03/09  12:50:44  jsb]
     * 
     * Revision 2.7.2.3  92/02/18  19:17:09  jeffreyh
     *      [intel] optionally execute optimized norma_ipc_kmsg_accept().
     *      [92/02/13  13:06:38  jeffreyh]
     * 
     * Revision 2.7.2.2  92/01/21  21:53:09  jsb
     *      De-linted.
     *      [92/01/17  12:21:06  jsb]
     * 
     * Revision 2.7.2.1  92/01/09  18:46:05  jsb
     *      Use netipc_thread_{lock,unlock} instead of spls.
     *      [92/01/08  10:23:36  jsb]
     * 
     * Revision 2.7  91/12/14  14:35:32  jsb
     *      Removed private assert definition.
     * 
     * Revision 2.6  91/09/04  11:28:45  jsb
     *      Use splhigh/splx instead of sploff/splon for now.
     *      [91/09/04  09:46:45  jsb]
     * 
     * Revision 2.5  91/08/28  11:16:12  jsb
     *      Renamed ast_clport things to ast_netipc things.
     *      [91/08/15  09:12:09  jsb]
     * 
     *      Fixed, and added counters.
     *      [91/08/14  19:22:35  jsb]
     * 
     * Revision 2.4  91/08/03  18:19:32  jsb
     *      Fixed include.
     *      [91/07/17  14:06:39  jsb]
     * 
     * Revision 2.3  91/06/17  15:48:02  jsb
     *      Changed norma include.
     *      [91/06/17  11:01:02  jsb]
     * 
     * Revision 2.2  91/06/06  17:56:02  jsb
     *      First checkin.
     *      [91/06/06  17:51:41  jsb]
     * 
     */
    /*
     *      File:   norma/ipc_wait.c
     *      Author: Joseph S. Barrera III
     *      Date:   1991
     */
    
    #include <mach_host.h>
    
    #include <mach/port.h>
    #include <mach/message.h>
    #include <kern/assert.h>
    #include <kern/counters.h>
    #include <kern/sched_prim.h>
    #include <kern/ipc_sched.h>
    #include <kern/ipc_kobject.h>
    #include <ipc/ipc_mqueue.h>
    #include <ipc/ipc_thread.h>
    #include <ipc/ipc_kmsg.h>
    #include <ipc/ipc_port.h>
    #include <ipc/ipc_pset.h>
    #include <ipc/ipc_space.h>
    #include <ipc/ipc_marequest.h>
    
    extern void netipc_thread_lock();
    extern void netipc_thread_unlock();
    
    /*
     * XXX Needs locking to be multiprocessor safe.
    * XXX We probably might also want per-processor spinning,
    * XXX although this will complicate the sending code.
    *
    * We signal that we are waiting by setting handoff_mqueue nonzero.
    * Our sender specifies that something has changed by setting msg nonzero.
    * We then signal that we are releasing this module by setting msg zero.
    *
    * YYY We've added locking so some of the comments above are out of data.
    *
    * XXX Should try having this loop handle asts?
    */
   ipc_mqueue_t    norma_ipc_handoff_mqueue;
   ipc_kmsg_t      norma_ipc_handoff_msg;
   mach_msg_size_t norma_ipc_handoff_max_size;
   mach_msg_size_t norma_ipc_handoff_msg_size;
   
   int c_break_reset = 0;
   int c_break_handoff = 0;
   int c_break_thread = 0;
   int c_break_gcount = 0;
   int c_break_lcount = 0;
   int c_break_ast = 0;
   int c_break_ast_terminate = 0;
   int c_break_ast_halt = 0;
   int c_break_ast_block = 0;
   int c_break_ast_network = 0;
   int c_break_ast_netipc = 0;
   
   #if     iPSC386 || iPSC860
   int     norma_ipc_kmsg_accept_disabled = 1;
   #endif  iPSC386 || iPSC860
   
   /*
    * Spin until something else is runnable or until a kmsg shows up.
    */
   ipc_kmsg_t
   norma_ipc_kmsg_accept(mqueue, max_size, msg_size)
           register volatile ipc_mqueue_t mqueue;
           mach_msg_size_t max_size;
           mach_msg_size_t *msg_size;
   {
           register processor_t myprocessor;
           register volatile thread_t *threadp;
           register volatile int *gcount;
           register volatile int *lcount;
           int mycpu;
   
   #if     iPSC386 || iPSC860
           if (norma_ipc_kmsg_accept_disabled) {
                   return IKM_NULL;
           }
   #endif  iPSC386 || iPSC860
   #if     1
           if (c_break_reset) {
                   c_break_reset = 0;
                   c_break_handoff = 0;
                   c_break_thread = 0;
                   c_break_gcount = 0;
                   c_break_lcount = 0;
                   c_break_ast = 0;
                   c_break_ast_halt = 0;
                   c_break_ast_terminate = 0;
                   c_break_ast_block = 0;
                   c_break_ast_network = 0;
                   c_break_ast_netipc = 0;
           }
   #endif
   
           mycpu = cpu_number();
           myprocessor = current_processor();
           threadp = (volatile thread_t *) &myprocessor->next_thread;
           lcount = (volatile int *) &myprocessor->runq.count;
   
           /*
            * Don't mark cpu idle; we still like our pmap.
            * XXX Will myprocessor->next_thread ever get set?
            */
   
   #if     MACH_HOST
           gcount = (volatile int *) &myprocessor->processor_set->runq.count;
   #else   MACH_HOST
           gcount = (volatile int *) &default_pset.runq.count;
   #endif  MACH_HOST
   
           /*
            * Indicate that we are spinning on this queue.
            *
            * Nonzero norma_ipc_handoff_mqueue keeps other receivers away.
            * Nonzero norma_ipc_handoff_msg keeps other senders away.
            */
           netipc_thread_lock();
           if (norma_ipc_handoff_mqueue != IMQ_NULL) {
                   printf("This is okay: handoff_mqueue conflict detected.\n");
                   netipc_thread_unlock();
                   return IKM_NULL;
           }
           assert(norma_ipc_handoff_msg == 0);
           norma_ipc_handoff_max_size = max_size;
           norma_ipc_handoff_msg_size = 0;
           norma_ipc_handoff_mqueue = mqueue;
           netipc_thread_unlock();
   
           /*
            * Spin until reschedule or kmsg handoff. Do asts in the meantime.
            */
           for (;;) {
                   if (norma_ipc_handoff_msg != IKM_NULL) {
                           c_break_handoff++;
                           break;
                   }
                   if (need_ast[mycpu]) {
                           if (need_ast[mycpu] & AST_HALT) {
                                   c_break_ast_halt++;
                           }
                           if (need_ast[mycpu] & AST_TERMINATE) {
                                   c_break_ast_terminate++;
                           }
                           if (need_ast[mycpu] & AST_BLOCK) {
                                   c_break_ast_block++;
                           }
                           if (need_ast[mycpu] & AST_NETWORK) {
                                   c_break_ast_network++;
                           }
                           if (need_ast[mycpu] & AST_NETIPC) {
                                   c_break_ast_netipc++;
                           }
                           c_break_ast++;
                           break;
                   }
                   if (*threadp != (volatile thread_t) THREAD_NULL) {
                           c_break_thread++;
                           break;
                   }
                   if (*gcount != 0) {
                           c_break_gcount++;
                           break;
                   }
                   if (*lcount != 0) {
                           c_break_lcount++;
                           break;
                   }
           }
   
           /*
            * Before we release mqueue, we must check for a delivered message.
            */
           netipc_thread_lock();
           if (norma_ipc_handoff_msg != IKM_NULL) {
                   /*
                    * Someone left us a message,
                    * or an indication of a message that was too large.
                    */
                   if (norma_ipc_handoff_msg_size) {
                           *msg_size = norma_ipc_handoff_msg_size;
                           norma_ipc_handoff_mqueue = IMQ_NULL;
                           norma_ipc_handoff_msg = IKM_NULL;
                           netipc_thread_unlock();
                           return IKM_NULL;
                   } else {
                           register ipc_kmsg_t kmsg;
                           kmsg = norma_ipc_handoff_msg;
                           norma_ipc_handoff_mqueue = IMQ_NULL;
                           norma_ipc_handoff_msg = IKM_NULL;
                           netipc_thread_unlock();
                           return kmsg;
                   }
           }
           norma_ipc_handoff_mqueue = IMQ_NULL;
           norma_ipc_handoff_msg = IKM_NULL;
           assert(ipc_kmsg_queue_first(&mqueue->imq_messages) == IKM_NULL);
           netipc_thread_unlock();
           return IKM_NULL;
   }

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