WebSVN – HelenOS – Diff – /branches/tracing/kernel/generic/src/ipc/ipc.c

 /*
  * Copyright (c) 2006 Ondrej Palkovsky
  * All rights reserved.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
+ *
  * - Redistributions of source code must retain the above copyright
  *   notice, this list of conditions and the following disclaimer.
  * - Redistributions in binary form must reproduce the above copyright
  *   notice, this list of conditions and the following disclaimer in the
  *   documentation and/or other materials provided with the distribution.
  * - The name of the author may not be used to endorse or promote products
  *   derived from this software without specific prior written permission.
+ *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 /** @addtogroup genericipc
  * @{
  */
 /** @file
  */
 /* Lock ordering
+ *
  * First the answerbox, then the phone.
  */
 #include <synch/spinlock.h>
 #include <synch/waitq.h>
 #include <synch/synch.h>
 #include <ipc/ipc.h>
 #include <errno.h>
 #include <mm/slab.h>
 #include <arch.h>
 #include <proc/task.h>
 #include <memstr.h>
 #include <debug.h>
 #include <print.h>
+#include <console/klog.h>
 #include <proc/thread.h>
 #include <arch/interrupt.h>
 #include <ipc/irq.h>
 /** Open channel that is assigned automatically to new tasks */
 answerbox_t *ipc_phone_0 = NULL;
 static slab_cache_t *ipc_call_slab;
 /** Initialize a call structure.
+ *
  * @param call      Call structure to be initialized.
  */
 static void _ipc_call_init(call_t *call)
+{
     memsetb((uintptr_t) call, sizeof(*call), 0);
     call->callerbox = &TASK->answerbox;
     call->sender = TASK;
     call->buffer = NULL;
+}
 /** Allocate and initialize a call structure.
+ *
  * The call is initialized, so that the reply will be directed to
  * TASK->answerbox.
+ *
  * @param flags     Parameters for slab_alloc (e.g FRAME_ATOMIC).
+ *
  * @return      If flags permit it, return NULL, or initialized kernel
  *          call structure.
  */
 call_t *ipc_call_alloc(int flags)
+{
     call_t *call;
     call = slab_alloc(ipc_call_slab, flags);
     _ipc_call_init(call);
     return call;
+}
 /** Initialize a statically allocated call structure.
+ *
  * @param call      Statically allocated kernel call structure to be
  *          initialized.
  */
 void ipc_call_static_init(call_t *call)
+{
     _ipc_call_init(call);
     call->flags |= IPC_CALL_STATIC_ALLOC;
+}
 /** Deallocate a call structure.
+ *
  * @param call      Call structure to be freed.
  */
 void ipc_call_free(call_t *call)
+{
     ASSERT(!(call->flags & IPC_CALL_STATIC_ALLOC));
     /* Check to see if we have data in the IPC_M_DATA_SEND buffer. */
     if (call->buffer)
         free(call->buffer);
     slab_free(ipc_call_slab, call);
+}
 /** Initialize an answerbox structure.
+ *
  * @param box       Answerbox structure to be initialized.
  * @param task      Task to which the answerbox belongs.
  */
 void ipc_answerbox_init(answerbox_t *box, task_t *task)
+{
     spinlock_initialize(&box->lock, "ipc_box_lock");
     spinlock_initialize(&box->irq_lock, "ipc_box_irqlock");
     waitq_initialize(&box->wq);
     list_initialize(&box->connected_phones);
     list_initialize(&box->calls);
     list_initialize(&box->dispatched_calls);
     list_initialize(&box->answers);
     list_initialize(&box->irq_notifs);
     list_initialize(&box->irq_head);
     box->task = task;
+}
 /** Connect a phone to an answerbox.
+ *
  * @param phone     Initialized phone structure.
  * @param box       Initialized answerbox structure.
  */
 void ipc_phone_connect(phone_t *phone, answerbox_t *box)
+{
     spinlock_lock(&phone->lock);
     phone->state = IPC_PHONE_CONNECTED;
     phone->callee = box;
     spinlock_lock(&box->lock);
     list_append(&phone->link, &box->connected_phones);
     spinlock_unlock(&box->lock);
     spinlock_unlock(&phone->lock);
+}
 /** Initialize a phone structure.
+ *
  * @param phone     Phone structure to be initialized.
  */
 void ipc_phone_init(phone_t *phone)
+{
     spinlock_initialize(&phone->lock, "phone_lock");
     phone->callee = NULL;
     phone->state = IPC_PHONE_FREE;
     atomic_set(&phone->active_calls, 0);
+}
 /** Helper function to facilitate synchronous calls.
+ *
  * @param phone     Destination kernel phone structure.
  * @param request   Call structure with request.
  */
 void ipc_call_sync(phone_t *phone, call_t *request)
+{
     answerbox_t sync_box;
     ipc_answerbox_init(&sync_box, TASK);
     /* We will receive data in a special box. */
     request->callerbox = &sync_box;
     ipc_call(phone, request);
     ipc_wait_for_call(&sync_box, SYNCH_NO_TIMEOUT, SYNCH_FLAGS_NONE);
+}
 /** Answer a message which was not dispatched and is not listed in any queue.
+ *
  * @param call      Call structure to be answered.
  */
 static void _ipc_answer_free_call(call_t *call)
+{
     answerbox_t *callerbox = call->callerbox;
     call->flags |= IPC_CALL_ANSWERED;
     spinlock_lock(&callerbox->lock);
     list_append(&call->link, &callerbox->answers);
     spinlock_unlock(&callerbox->lock);
     waitq_wakeup(&callerbox->wq, WAKEUP_FIRST);
+}
 /** Answer a message which is in a callee queue.
+ *
  * @param box       Answerbox that is answering the message.
  * @param call      Modified request that is being sent back.
  */
 void ipc_answer(answerbox_t *box, call_t *call)
+{
     /* Remove from active box */
     spinlock_lock(&box->lock);
     list_remove(&call->link);
     spinlock_unlock(&box->lock);
     /* Send back answer */
     _ipc_answer_free_call(call);
+}
 /** Simulate sending back a message.
+ *
  * Most errors are better handled by forming a normal backward
  * message and sending it as a normal answer.
+ *
  * @param phone     Phone structure the call should appear to come from.
  * @param call      Call structure to be answered.
  * @param err       Return value to be used for the answer.
  */
 void ipc_backsend_err(phone_t *phone, call_t *call, unative_t err)
+{
     call->data.phone = phone;
     atomic_inc(&phone->active_calls);
     IPC_SET_RETVAL(call->data, err);
     _ipc_answer_free_call(call);
+}
 /** Unsafe unchecking version of ipc_call.
+ *
  * @param phone     Phone structure the call comes from.
  * @param box       Destination answerbox structure.
  * @param call      Call structure with request.
  */
 static void _ipc_call(phone_t *phone, answerbox_t *box, call_t *call)
+{
     if (!(call->flags & IPC_CALL_FORWARDED)) {
         atomic_inc(&phone->active_calls);
         call->data.phone = phone;
+    }
     spinlock_lock(&box->lock);
     list_append(&call->link, &box->calls);
     spinlock_unlock(&box->lock);
     waitq_wakeup(&box->wq, WAKEUP_FIRST);
+}
 /** Send an asynchronous request using a phone to an answerbox.
+ *
  * @param phone     Phone structure the call comes from and which is
  *          connected to the destination answerbox.
  * @param call      Call structure with request.
+ *
  * @return      Return 0 on success, ENOENT on error.
  */
 int ipc_call(phone_t *phone, call_t *call)
+{
     answerbox_t *box;
     spinlock_lock(&phone->lock);
     if (phone->state != IPC_PHONE_CONNECTED) {
         spinlock_unlock(&phone->lock);
         if (call->flags & IPC_CALL_FORWARDED) {
             IPC_SET_RETVAL(call->data, EFORWARD);
             _ipc_answer_free_call(call);
         } else {
             if (phone->state == IPC_PHONE_HUNGUP)
                 ipc_backsend_err(phone, call, EHANGUP);
             else
                 ipc_backsend_err(phone, call, ENOENT);
+        }
         return ENOENT;
+    }
     box = phone->callee;
     _ipc_call(phone, box, call);
     spinlock_unlock(&phone->lock);
     return 0;
+}
 /** Disconnect phone from answerbox.
+ *
  * This call leaves the phone in the HUNGUP state. The change to 'free' is done
  * lazily later.
+ *
  * @param phone     Phone structure to be hung up.
+ *
  * @return      Return 0 if the phone is disconnected.
  *          Return -1 if the phone was already disconnected.
  */
 int ipc_phone_hangup(phone_t *phone)
+{
     answerbox_t *box;
     call_t *call;
     spinlock_lock(&phone->lock);
     if (phone->state == IPC_PHONE_FREE ||
         phone->state == IPC_PHONE_HUNGUP ||
         phone->state == IPC_PHONE_CONNECTING) {
         spinlock_unlock(&phone->lock);
         return -1;
+    }
     box = phone->callee;
     if (phone->state != IPC_PHONE_SLAMMED) {
         /* Remove myself from answerbox */
         spinlock_lock(&box->lock);
         list_remove(&phone->link);
         spinlock_unlock(&box->lock);
         if (phone->state != IPC_PHONE_SLAMMED) {
             call = ipc_call_alloc(0);
             IPC_SET_METHOD(call->data, IPC_M_PHONE_HUNGUP);
             call->flags |= IPC_CALL_DISCARD_ANSWER;
             _ipc_call(phone, box, call);
+        }
+    }
     phone->state = IPC_PHONE_HUNGUP;
     spinlock_unlock(&phone->lock);
     return 0;
+}
 /** Forwards call from one answerbox to another one.
+ *
  * @param call      Call structure to be redirected.
  * @param newphone  Phone structure to target answerbox.
  * @param oldbox    Old answerbox structure.
  * @param mode      Flags that specify mode of the forward operation.
+ *
  * @return      Return 0 if forwarding succeeded or an error code if
  *          there was error.
+ *
  * The return value serves only as an information for the forwarder,
  * the original caller is notified automatically with EFORWARD.
  */
 int ipc_forward(call_t *call, phone_t *newphone, answerbox_t *oldbox, int mode)
+{
     spinlock_lock(&oldbox->lock);
     list_remove(&call->link);
     spinlock_unlock(&oldbox->lock);
     if (mode & IPC_FF_ROUTE_FROM_ME)
         call->data.phone = newphone;
     return ipc_call(newphone, call);
+}
 /** Wait for a phone call.
+ *
  * @param box       Answerbox expecting the call.
  * @param usec      Timeout in microseconds. See documentation for
  *          waitq_sleep_timeout() for decription of its special
  *          meaning.
  * @param flags     Select mode of sleep operation. See documentation for
  *          waitq_sleep_timeout() for description of its special
  *          meaning.
  * @return      Recived call structure or NULL.
+ *
  * To distinguish between a call and an answer, have a look at call->flags.
  */
 call_t *ipc_wait_for_call(answerbox_t *box, uint32_t usec, int flags)
+{
     call_t *request;
     ipl_t ipl;
     int rc;
 restart:
     rc = waitq_sleep_timeout(&box->wq, usec, flags);
     if (SYNCH_FAILED(rc))
         return NULL;
     spinlock_lock(&box->lock);
     if (!list_empty(&box->irq_notifs)) {
         ipl = interrupts_disable();
         spinlock_lock(&box->irq_lock);
         request = list_get_instance(box->irq_notifs.next, call_t, link);
         list_remove(&request->link);
         spinlock_unlock(&box->irq_lock);
         interrupts_restore(ipl);
     } else if (!list_empty(&box->answers)) {
         /* Handle asynchronous answers */
         request = list_get_instance(box->answers.next, call_t, link);
         list_remove(&request->link);
         atomic_dec(&request->data.phone->active_calls);
     } else if (!list_empty(&box->calls)) {
         /* Handle requests */
         request = list_get_instance(box->calls.next, call_t, link);
         list_remove(&request->link);
         /* Append request to dispatch queue */
         list_append(&request->link, &box->dispatched_calls);
     } else {
         /* This can happen regularly after ipc_cleanup */
         spinlock_unlock(&box->lock);
         goto restart;
+    }
     spinlock_unlock(&box->lock);
     return request;
+}
 /** Answer all calls from list with EHANGUP answer.
+ *
  * @param lst       Head of the list to be cleaned up.
  */
 static void ipc_cleanup_call_list(link_t *lst)
+{
     call_t *call;
     while (!list_empty(lst)) {
         call = list_get_instance(lst->next, call_t, link);
         if (call->buffer)
             free(call->buffer);
         list_remove(&call->link);
         IPC_SET_RETVAL(call->data, EHANGUP);
         _ipc_answer_free_call(call);
+    }
+}
-/** Cleans up all IPC communication of the current task.
+/** Disconnects all phones connected to an answerbox.
+ *
- * Note: ipc_hangup sets returning answerbox to TASK->answerbox, you
+ * @param box       Answerbox to disconnect phones from.
- * have to change it as well if you want to cleanup other tasks than TASK.
+ * @param notify_box    If true, the answerbox will get a hangup message for
+ *          each disconnected phone.
  */
-void ipc_cleanup(void)
+static void ipc_answerbox_slam_phones(answerbox_t *box, bool notify_box)
+{
-    int i;
-    call_t *call;
     phone_t *phone;
     DEADLOCK_PROBE_INIT(p_phonelck);
+    ipl_t ipl;
+    call_t *call;
-    /* Disconnect all our phones ('ipc_phone_hangup') */
-    for (i = 0; i < IPC_MAX_PHONES; i++)
-        ipc_phone_hangup(&TASK->phones[i]);
-    /* Disconnect all connected irqs */
-    ipc_irq_cleanup(&TASK->answerbox);
+    call = ipc_call_alloc(0);
     /* Disconnect all phones connected to our answerbox */
 restart_phones:
+    ipl = interrupts_disable();
-    spinlock_lock(&TASK->answerbox.lock);
+    spinlock_lock(&box->lock);
-    while (!list_empty(&TASK->answerbox.connected_phones)) {
+    while (!list_empty(&box->connected_phones)) {
-        phone = list_get_instance(TASK->answerbox.connected_phones.next,
+        phone = list_get_instance(box->connected_phones.next,
             phone_t, link);
         if (!spinlock_trylock(&phone->lock)) {
-            spinlock_unlock(&TASK->answerbox.lock);
+            spinlock_unlock(&box->lock);
+            interrupts_restore(ipl);
             DEADLOCK_PROBE(p_phonelck, DEADLOCK_THRESHOLD);
             goto restart_phones;
+        }
         /* Disconnect phone */
         ASSERT(phone->state == IPC_PHONE_CONNECTED);
-        phone->state = IPC_PHONE_SLAMMED;
         list_remove(&phone->link);
+        phone->state = IPC_PHONE_SLAMMED;
+        if (notify_box) {
+            spinlock_unlock(&phone->lock);
+            spinlock_unlock(&box->lock);
+            interrupts_restore(ipl);
+            /*
+             * Send one message to the answerbox for each
+             * phone. Used to make sure the kbox thread
+             * wakes up after the last phone has been
+             * disconnected.
+             */
+            IPC_SET_METHOD(call->data, IPC_M_PHONE_HUNGUP);
+            call->flags |= IPC_CALL_DISCARD_ANSWER;
+            _ipc_call(phone, box, call);
+            /* Allocate another call in advance */
+            call = ipc_call_alloc(0);
+            /* Must start again */
+            goto restart_phones;
+        }
         spinlock_unlock(&phone->lock);
+    }
+    spinlock_unlock(&box->lock);
+    interrupts_restore(ipl);
+    /* Free unused call */
+    if (call) ipc_call_free(call);
+}
+static void ipc_kbox_cleanup()
+{
+    ipl_t ipl;
+    bool have_kb_thread;
+    /* Only hold kb_cleanup_lock while setting kb_finished - this is enough */
+    ipl = interrupts_disable();
+    spinlock_lock(&TASK->kb_cleanup_lock);
+    TASK->kb_finished = true;
+    spinlock_unlock(&TASK->kb_cleanup_lock);
+    interrupts_restore(ipl);
+    have_kb_thread = (TASK->kb_thread != NULL);
+    /* From now on nobody will try to connect phones or attach kbox threads */
+    /*
+     * Disconnect all phones connected to our kbox. Passing true for
+     * notify_box causes a HANGUP message to be inserted for each
+     * disconnected phone. This ensures the kbox thread is going to
+     * wake up and terminate.
+     */
+    ipc_answerbox_slam_phones(&TASK->kernel_box, have_kb_thread);
+    /* TODO: Wait for kbox thread to terminate */
+    if (have_kb_thread) {
+        klog_printf("ipc_kbox_cleanup - wait for kbox thread to finish");
+        waitq_sleep(&TASK->kb_thread_shutdown_wq);
+    }
     /* Answer all messages in 'calls' and 'dispatched_calls' queues */
+    spinlock_lock(&TASK->kernel_box.lock);
+    ipc_cleanup_call_list(&TASK->kernel_box.dispatched_calls);
+    ipc_cleanup_call_list(&TASK->kernel_box.calls);
+    spinlock_unlock(&TASK->kernel_box.lock);
+}
+/** Cleans up all IPC communication of the current task.
+ *
+ * Note: ipc_hangup sets returning answerbox to TASK->answerbox, you
+ * have to change it as well if you want to cleanup other tasks than TASK.
+ */
+void ipc_cleanup(void)
+{
+    int i;
+    call_t *call;
+    /* Disconnect all our phones ('ipc_phone_hangup') */
+    for (i = 0; i < IPC_MAX_PHONES; i++)
+        ipc_phone_hangup(&TASK->phones[i]);
+    /* Disconnect all connected irqs */
+    ipc_irq_cleanup(&TASK->answerbox);
+    /* Disconnect all phones connected to our regular answerbox */
+    ipc_answerbox_slam_phones(&TASK->answerbox, false);
+    /* Clean up kbox thread and communications */
+    ipc_kbox_cleanup();
+    /* Answer all messages in 'calls' and 'dispatched_calls' queues */
+    spinlock_lock(&TASK->answerbox.lock);
     ipc_cleanup_call_list(&TASK->answerbox.dispatched_calls);
     ipc_cleanup_call_list(&TASK->answerbox.calls);
     spinlock_unlock(&TASK->answerbox.lock);
     /* Wait for all async answers to arrive */
     while (1) {
         /* Go through all phones, until all are FREE... */
         /* Locking not needed, no one else should modify
          * it, when we are in cleanup */
         for (i = 0; i < IPC_MAX_PHONES; i++) {
             if (TASK->phones[i].state == IPC_PHONE_HUNGUP &&
                 atomic_get(&TASK->phones[i].active_calls) == 0)
                 TASK->phones[i].state = IPC_PHONE_FREE;
             /* Just for sure, we might have had some
              * IPC_PHONE_CONNECTING phones */
             if (TASK->phones[i].state == IPC_PHONE_CONNECTED)
                 ipc_phone_hangup(&TASK->phones[i]);
             /* If the hangup succeeded, it has sent a HANGUP
              * message, the IPC is now in HUNGUP state, we
              * wait for the reply to come */
             if (TASK->phones[i].state != IPC_PHONE_FREE)
                 break;
+        }
         /* Voila, got into cleanup */
         if (i == IPC_MAX_PHONES)
             break;
         call = ipc_wait_for_call(&TASK->answerbox, SYNCH_NO_TIMEOUT,
             SYNCH_FLAGS_NONE);
         ASSERT((call->flags & IPC_CALL_ANSWERED) ||
             (call->flags & IPC_CALL_NOTIF));
         ASSERT(!(call->flags & IPC_CALL_STATIC_ALLOC));
         atomic_dec(&TASK->active_calls);
         ipc_call_free(call);
+    }
+}
 /** Initilize IPC subsystem */
 void ipc_init(void)
+{
     ipc_call_slab = slab_cache_create("ipc_call", sizeof(call_t), 0, NULL,
         NULL, 0);
+}
 /** List answerbox contents.
+ *
  * @param taskid    Task ID.
  */
 void ipc_print_task(task_id_t taskid)
+{
     task_t *task;
     int i;
     call_t *call;
     link_t *tmp;
     spinlock_lock(&tasks_lock);
     task = task_find_by_id(taskid);
     if (task)
         spinlock_lock(&task->lock);
     spinlock_unlock(&tasks_lock);
     if (!task)
         return;
     /* Print opened phones & details */
     printf("PHONE:\n");
     for (i = 0; i < IPC_MAX_PHONES; i++) {
         spinlock_lock(&task->phones[i].lock);
         if (task->phones[i].state != IPC_PHONE_FREE) {
             printf("%d: ", i);
             switch (task->phones[i].state) {
             case IPC_PHONE_CONNECTING:
                 printf("connecting ");
                 break;
             case IPC_PHONE_CONNECTED:
                 printf("connected to: %p ",
                        task->phones[i].callee);
                 break;
             case IPC_PHONE_SLAMMED:
                 printf("slammed by: %p ",
                        task->phones[i].callee);
                 break;
             case IPC_PHONE_HUNGUP:
                 printf("hung up - was: %p ",
                        task->phones[i].callee);
                 break;
             default:
                 break;
+            }
             printf("active: %d\n",
                 atomic_get(&task->phones[i].active_calls));
+        }
         spinlock_unlock(&task->phones[i].lock);
+    }
     /* Print answerbox - calls */
     spinlock_lock(&task->answerbox.lock);
     printf("ABOX - CALLS:\n");
     for (tmp = task->answerbox.calls.next; tmp != &task->answerbox.calls;
         tmp = tmp->next) {
         call = list_get_instance(tmp, call_t, link);
         printf("Callid: %p Srctask:%llu M:%d A1:%d A2:%d A3:%d "
             "A4:%d A5:%d Flags:%x\n", call, call->sender->taskid,
             IPC_GET_METHOD(call->data), IPC_GET_ARG1(call->data),
             IPC_GET_ARG2(call->data), IPC_GET_ARG3(call->data),
             IPC_GET_ARG4(call->data), IPC_GET_ARG5(call->data),
             call->flags);
+    }
     /* Print answerbox - calls */
     printf("ABOX - DISPATCHED CALLS:\n");
     for (tmp=task->answerbox.dispatched_calls.next;
          tmp != &task->answerbox.dispatched_calls;
          tmp = tmp->next) {
         call = list_get_instance(tmp, call_t, link);
         printf("Callid: %p Srctask:%llu M:%d A1:%d A2:%d A3:%d "
             "A4:%d A5:%d Flags:%x\n", call, call->sender->taskid,
             IPC_GET_METHOD(call->data), IPC_GET_ARG1(call->data),
             IPC_GET_ARG2(call->data), IPC_GET_ARG3(call->data),
             IPC_GET_ARG4(call->data), IPC_GET_ARG5(call->data),
             call->flags);
+    }
     /* Print answerbox - calls */
     printf("ABOX - ANSWERS:\n");
     for (tmp = task->answerbox.answers.next; tmp != &task->answerbox.answers;
         tmp = tmp->next) {
         call = list_get_instance(tmp, call_t, link);
         printf("Callid:%p M:%d A1:%d A2:%d A3:%d A4:%d A5:%d Flags:%x\n",
             call, IPC_GET_METHOD(call->data), IPC_GET_ARG1(call->data),
             IPC_GET_ARG2(call->data), IPC_GET_ARG3(call->data),
             IPC_GET_ARG4(call->data), IPC_GET_ARG5(call->data),
             call->flags);
+    }
     spinlock_unlock(&task->answerbox.lock);
     spinlock_unlock(&task->lock);
+}
 #include <ipc/ipcrsc.h>
 #include <console/klog.h>
 #include <udebug/udebug_ipc.h>
 static void kbox_thread_proc(void *arg)
+{
     call_t *call;
     int method;
     bool done;
     ipl_t ipl;
     (void)arg;
     klog_printf("kbox_thread_proc()");
     done = false;
     while (!done) {
         klog_printf("kbox: wait for call");
         call = ipc_wait_for_call(&TASK->kernel_box, SYNCH_NO_TIMEOUT,
             SYNCH_FLAGS_NONE);
         if (call != NULL) {
             method = IPC_GET_METHOD(call->data);
             if (method == IPC_M_DEBUG_ALL) {
                 udebug_call_receive(call);
+            }
             if (method == IPC_M_PHONE_HUNGUP) {
-                klog_printf("kbox: handle hangup message\n");
+                klog_printf("kbox: handle hangup message");
                 /* Was it our debugger, who hung up? */
                 if (call->sender == TASK->debugger) {
                     /* Terminate debugging session (if any) */
-                    klog_printf("kbox: terminate debug session\n");
+                    klog_printf("kbox: terminate debug session");
                     ipl = interrupts_disable();
                     spinlock_lock(&TASK->lock);
                     udebug_task_cleanup(TASK);
                     spinlock_unlock(&TASK->lock);
                     interrupts_restore(ipl);
                 } else {
-                    klog_printf("kbox: was not debugger\n");
+                    klog_printf("kbox: was not debugger");
+                }
-                klog_printf("kbox: continue with hangup message\n");
+                klog_printf("kbox: continue with hangup message");
                 IPC_SET_RETVAL(call->data, 0);
                 ipc_answer(&TASK->kernel_box, call);
                 ipl = interrupts_disable();
                 spinlock_lock(&TASK->lock);
                 spinlock_lock(&TASK->answerbox.lock);
                 if (list_empty(&TASK->answerbox.connected_phones)) {
                     /* Last phone has been disconnected */
-                    TASK->kb_thread_at_hand = false;
                     TASK->kb_thread = NULL;
                     done = true;
-                    printf("phone list is empty\n");
+                    klog_printf("phone list is empty");
+                }
                 spinlock_unlock(&TASK->answerbox.lock);
                 spinlock_unlock(&TASK->lock);
                 interrupts_restore(ipl);
+            }
+        }
+    }
+    klog_printf("kbox: done, waking up possible shutdown routine");
+    waitq_wakeup(&TASK->kb_thread_shutdown_wq, WAKEUP_ALL);
     klog_printf("kbox: finished");
+}
 /**
  * Connect phone to a task kernel-box specified by id.
+ *
+ * Note that this is not completely atomic. For optimisation reasons,
+ * The task might start cleaning up kbox after the phone has been connected
+ * and before a kbox thread has been created. This must be taken into account
+ * in the cleanup code.
+ *
  * @return      Phone id on success, or negative error code.
  */
 int ipc_connect_kbox(task_id_t taskid)
+{
     int newphid;
     task_t *ta;
     thread_t *kb_thread;
-    int rc;
     ipl_t ipl;
+    bool had_kb_thread;
     newphid = phone_alloc();
     if (newphid < 0)
         return ELIMIT;
     ipl = interrupts_disable();
     spinlock_lock(&tasks_lock);
     ta = task_find_by_id(taskid);
     if (ta == NULL) {
         spinlock_unlock(&tasks_lock);
+        interrupts_restore(ipl);
         return ENOENT;
+    }
-    spinlock_lock(&ta->lock);
+    spinlock_lock(&ta->kb_cleanup_lock);
     spinlock_unlock(&tasks_lock);
+    /*
+     * Only ta->kb_cleanup_lock left. Since we checked the value
+     * of ta->kb_finished, this suffices to ensure the task's exitence.
+     * (And that it didn't start kbox cleanup yet). It also ensures
+     * mutual exclusion with other threads running this function.
+     */
+    if (ta->kb_finished != false) {
+        spinlock_unlock(&ta->kb_cleanup_lock);
+        interrupts_restore(ipl);
+        return EINVAL;
+    }
+    /* Connect the newly allocated phone to the kbox */
     ipc_phone_connect(&TASK->phones[newphid], &ta->kernel_box);
-    if (ta->kb_thread_at_hand == false) {
+    had_kb_thread = (ta->kb_thread != NULL);
+    /*
+     * Release all locks. This is an optimisation, that makes
-        ta->kb_thread_at_hand = true;
+     * unnecessary thread creation very unlikely.
+     */
-        spinlock_unlock(&ta->lock);
+    spinlock_unlock(&ta->kb_cleanup_lock);
-        interrupts_restore(ipl);
+    interrupts_restore(ipl);
+    /* Create a kbox thread */
-        kb_thread = thread_create(kbox_thread_proc,
+    kb_thread = thread_create(kbox_thread_proc,
-            NULL, ta, THREAD_FLAG_NOATTACH, "kbox", false);
+        NULL, ta, THREAD_FLAG_NOATTACH, "kbox", false);
-        if (!kb_thread)
+    if (!kb_thread)
-            return ENOMEM;
+        return ENOMEM;
+    /*
+     * It might happen that someone else has attached a kbox thread.
+     * in the meantime. Also, the task might have gone or shut down.
-        rc = thread_attach_by_id(kb_thread, taskid);
+     * Let's try from the beginning.
+     */
-        if (rc == EOK) {
-            ipl = interrupts_disable();
+    ipl = interrupts_disable();
-            spinlock_lock(&ta->lock);
+    spinlock_lock(&tasks_lock);
-            ta->kb_thread = kb_thread;
+    ta = task_find_by_id(taskid);
+    if (ta == NULL) {
-            spinlock_unlock(&ta->lock);
+        spinlock_unlock(&tasks_lock);
+        return ENOENT;
+    }
+    spinlock_lock(&ta->kb_cleanup_lock);
+    spinlock_unlock(&tasks_lock);
+    if (ta->kb_finished != false || ta->kb_thread != NULL) {
+        spinlock_unlock(&ta->kb_cleanup_lock);
-            interrupts_restore(ipl);
+        interrupts_restore(ipl);
+        /*
-            thread_detach(kb_thread);
+         * Release the allocated thread struct. This won't
+         * happen too often, only if two CPUs raced for
-            thread_ready(kb_thread);
+         * connecting to the kbox.
-        } else {
+         */
-            /* Return the allocated thread struct */
-            thread_unattached_free(kb_thread);
+        thread_unattached_free(kb_thread);
+        return EINVAL;
+    }
-    } else {
+    /* Attach thread */
+    ta->kb_thread = kb_thread;
+    thread_attach(kb_thread, ta);
+    thread_detach(kb_thread);
+    thread_ready(kb_thread);
-        spinlock_unlock(&ta->lock);
+    spinlock_unlock(&ta->kb_cleanup_lock);
-        interrupts_restore(ipl);
+    interrupts_restore(ipl);
-    }
     return newphid;
+}
 /** @}
  */

Subversion Repositories HelenOS

(root)/branches/tracing/kernel/generic/src/ipc/ipc.c @ 2847 – Rev 2870 → 2902