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  1. /*
  2.  * Copyright (c) 2008 Jiri Svoboda
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup genericipc
  30.  * @{
  31.  */
  32. /** @file
  33.  */
  34.  
  35. #include <synch/synch.h>
  36. #include <synch/spinlock.h>
  37. #include <synch/mutex.h>
  38. #include <ipc/ipc.h>
  39. #include <ipc/ipcrsc.h>
  40. #include <arch.h>
  41. #include <errno.h>
  42. #include <debug.h>
  43. #include <udebug/udebug_ipc.h>
  44. #include <ipc/kbox.h>
  45.  
  46. void ipc_kbox_cleanup(void)
  47. {
  48.     ipl_t ipl;
  49.     bool have_kb_thread;
  50.  
  51.     /* Only hold kb_cleanup_lock while setting kb_finished - this is enough */
  52.     mutex_lock(&TASK->kb_cleanup_lock);
  53.     TASK->kb_finished = true;
  54.     mutex_unlock(&TASK->kb_cleanup_lock);
  55.  
  56.     have_kb_thread = (TASK->kb_thread != NULL);
  57.  
  58.     /* From now on nobody will try to connect phones or attach kbox threads */
  59.  
  60.     /*
  61.      * Disconnect all phones connected to our kbox. Passing true for
  62.      * notify_box causes a HANGUP message to be inserted for each
  63.      * disconnected phone. This ensures the kbox thread is going to
  64.      * wake up and terminate.
  65.      */
  66.     ipc_answerbox_slam_phones(&TASK->kernel_box, have_kb_thread);
  67.  
  68.     /*
  69.      * If the task was being debugged, clean up debugging session.
  70.      * This is necessarry as slamming the phones won't force
  71.      * kbox thread to clean it up since sender != debugger.
  72.      */
  73.     ipl = interrupts_disable();
  74.     spinlock_lock(&TASK->lock);
  75.     udebug_task_cleanup(TASK);
  76.     spinlock_unlock(&TASK->lock);
  77.     interrupts_restore(ipl);
  78.    
  79.     if (have_kb_thread) {
  80.         LOG("join kb_thread..\n");
  81.         thread_join(TASK->kb_thread);
  82.         thread_detach(TASK->kb_thread);
  83.         LOG("join done\n");
  84.         TASK->kb_thread = NULL;
  85.     }
  86.  
  87.     /* Answer all messages in 'calls' and 'dispatched_calls' queues */
  88.     spinlock_lock(&TASK->kernel_box.lock);
  89.     ipc_cleanup_call_list(&TASK->kernel_box.dispatched_calls);
  90.     ipc_cleanup_call_list(&TASK->kernel_box.calls);
  91.     spinlock_unlock(&TASK->kernel_box.lock);
  92. }
  93.  
  94. /** Handle hangup message in kbox.
  95.  *
  96.  * @param call  The IPC_M_PHONE_HUNGUP call structure.
  97.  * @param last  Output, the function stores @c true here if
  98.  *      this was the last phone, @c false otherwise.
  99.  **/
  100. static void kbox_proc_phone_hungup(call_t *call, bool *last)
  101. {
  102.     ipl_t ipl;
  103.  
  104.     LOG("kbox_proc_phone_hungup()\n");
  105.  
  106.     /* Was it our debugger, who hung up? */
  107.     if (call->sender == TASK->udebug.debugger) {
  108.         /* Terminate debugging session (if any) */
  109.         LOG("kbox: terminate debug session\n");
  110.         ipl = interrupts_disable();
  111.         spinlock_lock(&TASK->lock);
  112.         udebug_task_cleanup(TASK);
  113.         spinlock_unlock(&TASK->lock);
  114.         interrupts_restore(ipl);
  115.     } else {
  116.         LOG("kbox: was not debugger\n");
  117.     }
  118.  
  119.     LOG("kbox: continue with hangup message\n");
  120.     IPC_SET_RETVAL(call->data, 0);
  121.     ipc_answer(&TASK->kernel_box, call);
  122.  
  123.     ipl = interrupts_disable();
  124.     spinlock_lock(&TASK->lock);
  125.     spinlock_lock(&TASK->answerbox.lock);
  126.     if (list_empty(&TASK->answerbox.connected_phones)) {
  127.         /*
  128.          * Last phone has been disconnected. Detach this thread so it
  129.          * gets freed and signal to the caller.
  130.          */
  131.  
  132.         /* Only detach kbox thread unless already terminating. */
  133.         mutex_lock(&TASK->kb_cleanup_lock);
  134.         if (&TASK->kb_finished == false) {
  135.             /* Detach kbox thread so it gets freed from memory. */
  136.             thread_detach(TASK->kb_thread);
  137.             TASK->kb_thread = NULL;
  138.         }
  139.         mutex_unlock(&TASK->kb_cleanup_lock);
  140.  
  141.         LOG("phone list is empty\n");
  142.         *last = true;
  143.     } else {
  144.         *last = false;
  145.     }
  146.  
  147.     spinlock_unlock(&TASK->answerbox.lock);
  148.     spinlock_unlock(&TASK->lock);
  149.     interrupts_restore(ipl);
  150. }
  151.  
  152. /** Implementing function for the kbox thread.
  153.  *
  154.  * This function listens for debug requests. It terminates
  155.  * when all phones are disconnected from the kbox.
  156.  *
  157.  * @param arg   Ignored.
  158.  */
  159. static void kbox_thread_proc(void *arg)
  160. {
  161.     call_t *call;
  162.     bool done;
  163.  
  164.     (void)arg;
  165.     LOG("kbox_thread_proc()\n");
  166.     done = false;
  167.  
  168.     while (!done) {
  169.         call = ipc_wait_for_call(&TASK->kernel_box, SYNCH_NO_TIMEOUT,
  170.             SYNCH_FLAGS_NONE);
  171.  
  172.         if (call == NULL)
  173.             continue;   /* Try again. */
  174.  
  175.         switch (IPC_GET_METHOD(call->data)) {
  176.  
  177.         case IPC_M_DEBUG_ALL:
  178.             /* Handle debug call. */
  179.             udebug_call_receive(call);
  180.             break;
  181.  
  182.         case IPC_M_PHONE_HUNGUP:
  183.             /*
  184.              * Process the hangup call. If this was the last
  185.              * phone, done will be set to true and the
  186.              * while loop will terminate.
  187.              */
  188.             kbox_proc_phone_hungup(call, &done);
  189.             break;
  190.  
  191.         default:
  192.             /* Ignore */
  193.             break;
  194.         }
  195.     }
  196.  
  197.     LOG("kbox: finished\n");
  198. }
  199.  
  200.  
  201. /**
  202.  * Connect phone to a task kernel-box specified by id.
  203.  *
  204.  * Note that this is not completely atomic. For optimisation reasons,
  205.  * The task might start cleaning up kbox after the phone has been connected
  206.  * and before a kbox thread has been created. This must be taken into account
  207.  * in the cleanup code.
  208.  *
  209.  * @return      Phone id on success, or negative error code.
  210.  */
  211. int ipc_connect_kbox(task_id_t taskid)
  212. {
  213.     int newphid;
  214.     task_t *ta;
  215.     thread_t *kb_thread;
  216.     ipl_t ipl;
  217.  
  218.     ipl = interrupts_disable();
  219.     spinlock_lock(&tasks_lock);
  220.  
  221.     ta = task_find_by_id(taskid);
  222.     if (ta == NULL) {
  223.         spinlock_unlock(&tasks_lock);
  224.         interrupts_restore(ipl);
  225.         return ENOENT;
  226.     }
  227.  
  228.     atomic_inc(&ta->refcount);
  229.  
  230.     spinlock_unlock(&tasks_lock);
  231.     interrupts_restore(ipl);
  232.  
  233.     mutex_lock(&ta->kb_cleanup_lock);
  234.  
  235.     if (atomic_predec(&ta->refcount) == 0) {
  236.         mutex_unlock(&ta->kb_cleanup_lock);
  237.         task_destroy(ta);
  238.         return ENOENT;
  239.     }
  240.  
  241.     if (ta->kb_finished != false) {
  242.         mutex_unlock(&ta->kb_cleanup_lock);
  243.         return EINVAL;
  244.     }
  245.  
  246.     newphid = phone_alloc();
  247.     if (newphid < 0) {
  248.         mutex_unlock(&ta->kb_cleanup_lock);
  249.         return ELIMIT;
  250.     }
  251.  
  252.     /* Connect the newly allocated phone to the kbox */
  253.     ipc_phone_connect(&TASK->phones[newphid], &ta->kernel_box);
  254.  
  255.     if (ta->kb_thread != NULL) {
  256.         mutex_unlock(&ta->kb_cleanup_lock);
  257.         return newphid;
  258.     }
  259.  
  260.     /* Create a kbox thread */
  261.     kb_thread = thread_create(kbox_thread_proc, NULL, ta, 0, "kbox", false);
  262.     if (!kb_thread) {
  263.         mutex_unlock(&ta->kb_cleanup_lock);
  264.         return ENOMEM;
  265.     }
  266.  
  267.     ta->kb_thread = kb_thread;
  268.     thread_ready(kb_thread);
  269.  
  270.     mutex_unlock(&ta->kb_cleanup_lock);
  271.  
  272.     return newphid;
  273. }
  274.  
  275. /** @}
  276.  */
  277.