/*
* 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)
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)
list_remove(&call->link);
IPC_SET_RETVAL(call->data, EHANGUP);
_ipc_answer_free_call(call);
}
}
/** Disconnects all phones connected to an answerbox.
*
* @param box Answerbox to disconnect phones from.
* @param notify_box If true, the answerbox will get a hangup message for
* each disconnected phone.
*/
static void ipc_answerbox_slam_phones(answerbox_t *box, bool notify_box)
{
phone_t *phone;
DEADLOCK_PROBE_INIT(p_phonelck);
ipl_t ipl;
call_t *call;
call = ipc_call_alloc(0);
/* Disconnect all phones connected to our answerbox */
restart_phones:
ipl = interrupts_disable();
spinlock_lock(&box->lock);
while (!list_empty(&box->connected_phones)) {
phone = list_get_instance(box->connected_phones.next,
phone_t, link);
if (!spinlock_trylock(&phone->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);
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 */
for (i = 0; i < IPC_MAX_PHONES; i++) {
spinlock_lock(&task->phones[i].lock);
if (task->phones[i].state != IPC_PHONE_FREE) {
switch (task->phones[i].state) {
case IPC_PHONE_CONNECTING:
break;
case IPC_PHONE_CONNECTED:
task->phones[i].callee);
break;
case IPC_PHONE_SLAMMED:
task->phones[i].callee);
break;
case IPC_PHONE_HUNGUP:
task->phones[i].callee);
break;
default:
break;
}
atomic_get(&task->phones[i].active_calls));
}
spinlock_unlock(&task->phones[i].lock);
}
/* Print answerbox - calls */
spinlock_lock(&task->answerbox.lock);
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 */
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");
/* Was it our debugger, who hung up? */
if (call->sender == TASK->debugger) {
/* Terminate debugging session (if any) */
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");
}
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 = NULL;
done = true;
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;
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->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);
had_kb_thread = (ta->kb_thread != NULL);
/*
* Release all locks. This is an optimisation, that makes
* unnecessary thread creation very unlikely.
*/
spinlock_unlock(&ta->kb_cleanup_lock);
interrupts_restore(ipl);
/* Create a kbox thread */
kb_thread = thread_create(kbox_thread_proc,
NULL, ta, THREAD_FLAG_NOATTACH, "kbox", false);
if (!kb_thread)
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.
* Let's try from the beginning.
*/
ipl = interrupts_disable();
spinlock_lock(&tasks_lock);
ta = task_find_by_id(taskid);
if (ta == NULL) {
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);
/*
* Release the allocated thread struct. This won't
* happen too often, only if two CPUs raced for
* connecting to the kbox.
*/
thread_unattached_free(kb_thread);
return EINVAL;
}
/* Attach thread */
ta->kb_thread = kb_thread;
thread_attach(kb_thread, ta);
thread_detach(kb_thread);
thread_ready(kb_thread);
spinlock_unlock(&ta->kb_cleanup_lock);
interrupts_restore(ipl);
return newphid;
}
/** @}
*/