source: mainline/kernel/generic/src/ipc/ipc.c@ affaf2e

/*
 * 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/mutex.h>
#include <synch/waitq.h>
#include <ipc/ipc.h>
#include <abi/ipc/methods.h>
#include <ipc/kbox.h>
#include <ipc/event.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/console.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;
static slab_cache_t *ipc_answerbox_slab;

/** Initialize a call structure.
 *
 * @param call Call structure to be initialized.
 *
 */
static void _ipc_call_init(call_t *call)
{
        memsetb(call, sizeof(*call), 0);
        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(unsigned int flags)
{
        call_t *call = slab_alloc(ipc_call_slab, flags);
        if (call)
                _ipc_call_init(call);
        
        return call;
}

/** Deallocate a call structure.
 *
 * @param call Call structure to be freed.
 *
 */
void ipc_call_free(call_t *call)
{
        /* 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)
{
        irq_spinlock_initialize(&box->lock, "ipc.box.lock");
        irq_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_list);
        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)
{
        mutex_lock(&phone->lock);
        
        phone->state = IPC_PHONE_CONNECTED;
        phone->callee = box;
        
        irq_spinlock_lock(&box->lock, true);
        list_append(&phone->link, &box->connected_phones);
        irq_spinlock_unlock(&box->lock, true);
        
        mutex_unlock(&phone->lock);
}

/** Initialize a phone structure.
 *
 * @param phone Phone structure to be initialized.
 *
 */
void ipc_phone_init(phone_t *phone)
{
        mutex_initialize(&phone->lock, MUTEX_PASSIVE);
        phone->callee = NULL;
        phone->state = IPC_PHONE_FREE;
        atomic_set(&phone->active_calls, 0);
}

/** Answer a message which was not dispatched and is not listed in any queue.
 *
 * @param call       Call structure to be answered.
 * @param selflocked If true, then TASK->answebox is locked.
 *
 */
static void _ipc_answer_free_call(call_t *call, bool selflocked)
{
        answerbox_t *callerbox = &call->sender->answerbox;
        bool do_lock = ((!selflocked) || callerbox != (&TASK->answerbox));
        
        /* Count sent answer */
        irq_spinlock_lock(&TASK->lock, true);
        TASK->ipc_info.answer_sent++;
        irq_spinlock_unlock(&TASK->lock, true);
        
        call->flags |= IPC_CALL_ANSWERED;
        
        if (call->flags & IPC_CALL_FORWARDED) {
                if (call->caller_phone) {
                        /* Demasquerade the caller phone. */
                        call->data.phone = call->caller_phone;
                }
        }

        call->data.task_id = TASK->taskid;
        
        if (do_lock)
                irq_spinlock_lock(&callerbox->lock, true);
        
        list_append(&call->link, &callerbox->answers);
        
        if (do_lock)
                irq_spinlock_unlock(&callerbox->lock, true);
        
        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 */
        irq_spinlock_lock(&box->lock, true);
        list_remove(&call->link);
        irq_spinlock_unlock(&box->lock, true);
        
        /* Send back answer */
        _ipc_answer_free_call(call, false);
}

/** 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, sysarg_t err)
{
        call->data.phone = phone;
        atomic_inc(&phone->active_calls);
        IPC_SET_RETVAL(call->data, err);
        _ipc_answer_free_call(call, false);
}

/** 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)
{
        /* Count sent ipc call */
        irq_spinlock_lock(&TASK->lock, true);
        TASK->ipc_info.call_sent++;
        irq_spinlock_unlock(&TASK->lock, true);
        
        if (!(call->flags & IPC_CALL_FORWARDED)) {
                atomic_inc(&phone->active_calls);
                call->data.phone = phone;
                call->data.task_id = TASK->taskid;
        }
        
        irq_spinlock_lock(&box->lock, true);
        list_append(&call->link, &box->calls);
        irq_spinlock_unlock(&box->lock, true);
        
        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)
{
        mutex_lock(&phone->lock);
        if (phone->state != IPC_PHONE_CONNECTED) {
                mutex_unlock(&phone->lock);
                if (call->flags & IPC_CALL_FORWARDED) {
                        IPC_SET_RETVAL(call->data, EFORWARD);
                        _ipc_answer_free_call(call, false);
                } else {
                        if (phone->state == IPC_PHONE_HUNGUP)
                                ipc_backsend_err(phone, call, EHANGUP);
                        else
                                ipc_backsend_err(phone, call, ENOENT);
                }
                
                return ENOENT;
        }
        
        answerbox_t *box = phone->callee;
        _ipc_call(phone, box, call);
        
        mutex_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 0 if the phone is disconnected.
 * @return -1 if the phone was already disconnected.
 *
 */
int ipc_phone_hangup(phone_t *phone)
{
        mutex_lock(&phone->lock);
        if (phone->state == IPC_PHONE_FREE ||
            phone->state == IPC_PHONE_HUNGUP ||
            phone->state == IPC_PHONE_CONNECTING) {
                mutex_unlock(&phone->lock);
                return -1;
        }
        
        answerbox_t *box = phone->callee;
        if (phone->state != IPC_PHONE_SLAMMED) {
                /* Remove myself from answerbox */
                irq_spinlock_lock(&box->lock, true);
                list_remove(&phone->link);
                irq_spinlock_unlock(&box->lock, true);
                
                call_t *call = ipc_call_alloc(0);
                IPC_SET_IMETHOD(call->data, IPC_M_PHONE_HUNGUP);
                call->flags |= IPC_CALL_DISCARD_ANSWER;
                _ipc_call(phone, box, call);
        }
        
        phone->state = IPC_PHONE_HUNGUP;
        mutex_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 0 if forwarding succeeded or an error code if
 *         there was an 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,
    unsigned int mode)
{
        /* Count forwarded calls */
        irq_spinlock_lock(&TASK->lock, true);
        TASK->ipc_info.forwarded++;
        irq_spinlock_pass(&TASK->lock, &oldbox->lock);
        list_remove(&call->link);
        irq_spinlock_unlock(&oldbox->lock, true);
        
        if (mode & IPC_FF_ROUTE_FROM_ME) {
                if (!call->caller_phone)
                        call->caller_phone = call->data.phone;
                call->data.phone = newphone;
                call->data.task_id = TASK->taskid;
        }
        
        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, unsigned int flags)
{
        call_t *request;
        uint64_t irq_cnt = 0;
        uint64_t answer_cnt = 0;
        uint64_t call_cnt = 0;
        int rc;
        
restart:
        rc = waitq_sleep_timeout(&box->wq, usec, flags);
        if (SYNCH_FAILED(rc))
                return NULL;
        
        irq_spinlock_lock(&box->lock, true);
        if (!list_empty(&box->irq_notifs)) {
                /* Count received IRQ notification */
                irq_cnt++;
                
                irq_spinlock_lock(&box->irq_lock, false);
                
                request = list_get_instance(list_first(&box->irq_notifs),
                    call_t, link);
                list_remove(&request->link);
                
                irq_spinlock_unlock(&box->irq_lock, false);
        } else if (!list_empty(&box->answers)) {
                /* Count received answer */
                answer_cnt++;
                
                /* Handle asynchronous answers */
                request = list_get_instance(list_first(&box->answers),
                    call_t, link);
                list_remove(&request->link);
                atomic_dec(&request->data.phone->active_calls);
        } else if (!list_empty(&box->calls)) {
                /* Count received call */
                call_cnt++;
                
                /* Handle requests */
                request = list_get_instance(list_first(&box->calls),
                    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 */
                irq_spinlock_unlock(&box->lock, true);
                goto restart;
        }
        
        irq_spinlock_pass(&box->lock, &TASK->lock);
        
        TASK->ipc_info.irq_notif_received += irq_cnt;
        TASK->ipc_info.answer_received += answer_cnt;
        TASK->ipc_info.call_received += call_cnt;
        
        irq_spinlock_unlock(&TASK->lock, true);
        
        return request;
}

/** Answer all calls from list with EHANGUP answer.
 *
 * @param lst Head of the list to be cleaned up.
 *
 */
void ipc_cleanup_call_list(list_t *lst)
{
        while (!list_empty(lst)) {
                call_t *call = list_get_instance(list_first(lst), call_t, link);
                if (call->buffer)
                        free(call->buffer);
                
                list_remove(&call->link);
                
                IPC_SET_RETVAL(call->data, EHANGUP);
                _ipc_answer_free_call(call, true);
        }
}

/** 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.
 *
 */
void ipc_answerbox_slam_phones(answerbox_t *box, bool notify_box)
{
        phone_t *phone;
        DEADLOCK_PROBE_INIT(p_phonelck);
        
        call_t *call = notify_box ? ipc_call_alloc(0) : NULL;
        
        /* Disconnect all phones connected to our answerbox */
restart_phones:
        irq_spinlock_lock(&box->lock, true);
        while (!list_empty(&box->connected_phones)) {
                phone = list_get_instance(list_first(&box->connected_phones),
                    phone_t, link);
                if (SYNCH_FAILED(mutex_trylock(&phone->lock))) {
                        irq_spinlock_unlock(&box->lock, true);
                        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) {
                        mutex_unlock(&phone->lock);
                        irq_spinlock_unlock(&box->lock, true);
                        
                        /*
                         * 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_IMETHOD(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;
                }
                
                mutex_unlock(&phone->lock);
        }
        
        irq_spinlock_unlock(&box->lock, true);
        
        /* Free unused call */
        if (call)
                ipc_call_free(call);
}

/** Clean 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)
{
        /* Disconnect all our phones ('ipc_phone_hangup') */
        size_t i;
        for (i = 0; i < IPC_MAX_PHONES; i++)
                ipc_phone_hangup(&TASK->phones[i]);
        
        /* Unsubscribe from any event notifications. */
        event_cleanup_answerbox(&TASK->answerbox);
        
        /* Disconnect all connected irqs */
        ipc_irq_cleanup(&TASK->answerbox);
        
        /* Disconnect all phones connected to our regular answerbox */
        ipc_answerbox_slam_phones(&TASK->answerbox, false);
        
#ifdef CONFIG_UDEBUG
        /* Clean up kbox thread and communications */
        ipc_kbox_cleanup();
#endif
        
        /* Answer all messages in 'calls' and 'dispatched_calls' queues */
        irq_spinlock_lock(&TASK->answerbox.lock, true);
        ipc_cleanup_call_list(&TASK->answerbox.dispatched_calls);
        ipc_cleanup_call_list(&TASK->answerbox.calls);
        irq_spinlock_unlock(&TASK->answerbox.lock, true);
        
        /* Wait for all answers to asynchronous calls to arrive */
        while (true) {
                /*
                 * Go through all phones, until they are all FREE
                 * Locking is 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;
                                TASK->phones[i].callee = NULL;
                        }
                        
                        /*
                         * 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;
                }
                
                /* Got into cleanup */
                if (i == IPC_MAX_PHONES)
                        break;
                
                call_t *call = ipc_wait_for_call(&TASK->answerbox, SYNCH_NO_TIMEOUT,
                    SYNCH_FLAGS_NONE);
                ASSERT((call->flags & IPC_CALL_ANSWERED) ||
                    (call->flags & IPC_CALL_NOTIF));
                
                ipc_call_free(call);
        }
}

/** Initilize IPC subsystem
 *
 */
void ipc_init(void)
{
        ipc_call_slab = slab_cache_create("call_t", sizeof(call_t), 0, NULL,
            NULL, 0);
        ipc_answerbox_slab = slab_cache_create("answerbox_t",
            sizeof(answerbox_t), 0, NULL, NULL, 0);
}

/** List answerbox contents.
 *
 * @param taskid Task ID.
 *
 */
void ipc_print_task(task_id_t taskid)
{
        irq_spinlock_lock(&tasks_lock, true);
        task_t *task = task_find_by_id(taskid);
        
        if (!task) {
                irq_spinlock_unlock(&tasks_lock, true);
                return;
        }
        
        /* Hand-over-hand locking */
        irq_spinlock_exchange(&tasks_lock, &task->lock);
        
        printf("[phone id] [calls] [state\n");
        
        size_t i;
        for (i = 0; i < IPC_MAX_PHONES; i++) {
                if (SYNCH_FAILED(mutex_trylock(&task->phones[i].lock))) {
                        printf("%-10zu (mutex busy)\n", i);
                        continue;
                }
                
                if (task->phones[i].state != IPC_PHONE_FREE) {
                        printf("%-10zu %7" PRIun " ", i,
                            atomic_get(&task->phones[i].active_calls));
                        
                        switch (task->phones[i].state) {
                        case IPC_PHONE_CONNECTING:
                                printf("connecting");
                                break;
                        case IPC_PHONE_CONNECTED:
                                printf("connected to %" PRIu64 " (%s)",
                                    task->phones[i].callee->task->taskid,
                                    task->phones[i].callee->task->name);
                                break;
                        case IPC_PHONE_SLAMMED:
                                printf("slammed by %p",
                                    task->phones[i].callee);
                                break;
                        case IPC_PHONE_HUNGUP:
                                printf("hung up by %p",
                                    task->phones[i].callee);
                                break;
                        default:
                                break;
                        }
                        
                        printf("\n");
                }
                
                mutex_unlock(&task->phones[i].lock);
        }
        
        irq_spinlock_lock(&task->answerbox.lock, false);
        
#ifdef __32_BITS__
        printf("[call id ] [method] [arg1] [arg2] [arg3] [arg4] [arg5]"
            " [flags] [sender\n");
#endif
        
#ifdef __64_BITS__
        printf("[call id         ] [method] [arg1] [arg2] [arg3] [arg4]"
            " [arg5] [flags] [sender\n");
#endif
        
        printf(" --- incomming calls ---\n");
        list_foreach(task->answerbox.calls, cur) {
                call_t *call = list_get_instance(cur, call_t, link);
                
#ifdef __32_BITS__
                printf("%10p ", call);
#endif
                
#ifdef __64_BITS__
                printf("%18p ", call);
#endif
                
                printf("%-8" PRIun " %-6" PRIun " %-6" PRIun " %-6" PRIun
                    " %-6" PRIun " %-6" PRIun " %-7x %" PRIu64 " (%s)\n",
                    IPC_GET_IMETHOD(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, call->sender->taskid, call->sender->name);
        }
        
        printf(" --- dispatched calls ---\n");
        list_foreach(task->answerbox.dispatched_calls, cur) {
                call_t *call = list_get_instance(cur, call_t, link);
                
#ifdef __32_BITS__
                printf("%10p ", call);
#endif
                
#ifdef __64_BITS__
                printf("%18p ", call);
#endif
                
                printf("%-8" PRIun " %-6" PRIun " %-6" PRIun " %-6" PRIun
                    " %-6" PRIun " %-6" PRIun " %-7x %" PRIu64 " (%s)\n",
                    IPC_GET_IMETHOD(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, call->sender->taskid, call->sender->name);
        }
        
        printf(" --- incoming answers ---\n");
        list_foreach(task->answerbox.answers, cur) {
                call_t *call = list_get_instance(cur, call_t, link);
                
#ifdef __32_BITS__
                printf("%10p ", call);
#endif
                
#ifdef __64_BITS__
                printf("%18p ", call);
#endif
                
                printf("%-8" PRIun " %-6" PRIun " %-6" PRIun " %-6" PRIun
                    " %-6" PRIun " %-6" PRIun " %-7x %" PRIu64 " (%s)\n",
                    IPC_GET_IMETHOD(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, call->sender->taskid, call->sender->name);
        }
        
        irq_spinlock_unlock(&task->answerbox.lock, false);
        irq_spinlock_unlock(&task->lock, true);
}

/** @}
 */