WebSVN – HelenOS – Diff – /tags/0.1.1/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.
 */
 
/* Lock ordering
 *
 * First the answerbox, then the phone
 */
 
#include <synch/spinlock.h>
#include <synch/waitq.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 <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 new call */
static void _ipc_call_init(call_t *call)
{
    memsetb((__address)call, sizeof(*call), 0);
    call->callerbox = &TASK->answerbox;
    call->sender = TASK;
}
 
/** Allocate & initialize call structure
 *
 * The call is initialized, so that the reply will be directed
 * to TASK->answerbox
 *
 * @param flags Parameters for slab_alloc (ATOMIC, etc.)
 */
call_t * ipc_call_alloc(int flags)
{
    call_t *call;
 
    call = slab_alloc(ipc_call_slab, flags);
    _ipc_call_init(call);
 
    return call;
}
 
/** Initialize allocated call */
void ipc_call_static_init(call_t *call)
{
    _ipc_call_init(call);
    call->flags |= IPC_CALL_STATIC_ALLOC;
}
 
/** Deallocate call stracuture */
void ipc_call_free(call_t *call)
{
    slab_free(ipc_call_slab, call);
}
 
/** Initialize answerbox structure
 */
void ipc_answerbox_init(answerbox_t *box)
{
    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);
    box->task = TASK;
}
 
/** Connect phone to answerbox */
void ipc_phone_connect(phone_t *phone, answerbox_t *box)
{
    spinlock_lock(&phone->lock);
 
    ASSERT(!phone->callee);
    phone->busy = IPC_BUSY_CONNECTED;
    phone->callee = box;
 
    spinlock_lock(&box->lock);
    list_append(&phone->list, &box->connected_phones);
    spinlock_unlock(&box->lock);
 
    spinlock_unlock(&phone->lock);
}
 
/** Initialize phone structure and connect phone to answerbox
 */
void ipc_phone_init(phone_t *phone)
{
    spinlock_initialize(&phone->lock, "phone_lock");
    phone->callee = NULL;
    phone->busy = IPC_BUSY_FREE;
    atomic_set(&phone->active_calls, 0);
}
 
/** Helper function to facilitate synchronous calls */
void ipc_call_sync(phone_t *phone, call_t *request)
{
    answerbox_t sync_box;
 
    ipc_answerbox_init(&sync_box);
 
    /* We will receive data on special box */
    request->callerbox = &sync_box;
 
    ipc_call(phone, request);
    ipc_wait_for_call(&sync_box, 0);
}
 
/** Answer message that was not dispatched and is not entered in
 * any queue
 */
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->list, &callerbox->answers);
    spinlock_unlock(&callerbox->lock);
    waitq_wakeup(&callerbox->wq, 0);
}
 
/** Answer message, that is in 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->list);
    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.
 */
void ipc_backsend_err(phone_t *phone, call_t *call, __native err)
{
    call->data.phone = phone;
    atomic_inc(&phone->active_calls);
    if (phone->busy == IPC_BUSY_CONNECTED)
        IPC_SET_RETVAL(call->data, EHANGUP);
    else
        IPC_SET_RETVAL(call->data, ENOENT);
 
    _ipc_answer_free_call(call);
}
 
/* Unsafe unchecking ipc_call */
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->list, &box->calls);
    spinlock_unlock(&box->lock);
    waitq_wakeup(&box->wq, 0);
}
 
/** Send a asynchronous request using phone to answerbox
 *
 * @param phone Phone connected to answerbox
 * @param request Request to be sent
 */
int ipc_call(phone_t *phone, call_t *call)
{
    answerbox_t *box;
 
    spinlock_lock(&phone->lock);
 
    box = phone->callee;
    if (!box) {
        /* Trying to send over disconnected phone */
        spinlock_unlock(&phone->lock);
        if (call->flags & IPC_CALL_FORWARDED) {
            IPC_SET_RETVAL(call->data, EFORWARD);
            _ipc_answer_free_call(call);
        } else { /* Simulate sending back a message */
            if (phone->busy == IPC_BUSY_CONNECTED)
                ipc_backsend_err(phone, call, EHANGUP);
            else
                ipc_backsend_err(phone, call, ENOENT);
        }
 
        return ENOENT;
    }
    _ipc_call(phone, box, call);
   
    spinlock_unlock(&phone->lock);
    return 0;
}
 
/** Disconnect phone from answerbox
 *
 * It is allowed to call disconnect on already disconnected phone
 *
 * @return 0 - phone disconnected, -1 - the phone was already disconnected
 */
int ipc_phone_hangup(phone_t *phone)
{
    answerbox_t *box;
    call_t *call;
   
    spinlock_lock(&phone->lock);
    box = phone->callee;
    if (!box) {
        if (phone->busy == IPC_BUSY_CONNECTING) {
            spinlock_unlock(&phone->lock);
            return -1;
        }
        /* Already disconnected phone */
        phone->busy = IPC_BUSY_FREE;
        spinlock_unlock(&phone->lock);
        return 0;
    }
 
    spinlock_lock(&box->lock);
    list_remove(&phone->list);
    phone->callee = NULL;
    spinlock_unlock(&box->lock);
 
    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->busy = IPC_BUSY_FREE;
 
    spinlock_unlock(&phone->lock);
 
    return 0;
}
 
/** Forwards call from one answerbox to a new one
 *
 * @param call Call to be redirected.
 * @param newphone Phone to target answerbox.
 * @param oldbox Old answerbox
 * @return 0 on forward ok, 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)
{
    spinlock_lock(&oldbox->lock);
    list_remove(&call->list);
    spinlock_unlock(&oldbox->lock);
 
    return ipc_call(newphone, call);
}
 
 
/** Wait for phone call
 *
 * @return Recived message address
 * - to distinguish between call and answer, look at call->flags
 */
call_t * ipc_wait_for_call(answerbox_t *box, int flags)
{
    call_t *request;
    ipl_t ipl;
 
restart:      
    if (flags & IPC_WAIT_NONBLOCKING) {
        if (waitq_sleep_timeout(&box->wq,0,1) == ESYNCH_WOULD_BLOCK)
            return NULL;
    } else
        waitq_sleep(&box->wq);
   
    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, list);
        list_remove(&request->list);
 
        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, list);
        list_remove(&request->list);
        atomic_dec(&request->data.phone->active_calls);
    } else if (!list_empty(&box->calls)) {
        /* Handle requests */
        request = list_get_instance(box->calls.next, call_t, list);
        list_remove(&request->list);
        /* Append request to dispatch queue */
        list_append(&request->list, &box->dispatched_calls);
    } else {
        /* This can happen regularly after ipc_cleanup, remove
         * the warning in the future when the IPC is
         * more debugged */
        printf("WARNING: Spurious IPC wakeup.\n");
        spinlock_unlock(&box->lock);
        goto restart;
    }
    spinlock_unlock(&box->lock);
    return request;
}
 
/** Answer all calls from list with EHANGUP msg */
static void ipc_cleanup_call_list(link_t *lst)
{
    call_t *call;
 
    while (!list_empty(lst)) {
        call = list_get_instance(lst->next, call_t, list);
        list_remove(&call->list);
 
        IPC_SET_RETVAL(call->data, EHANGUP);
        _ipc_answer_free_call(call);
    }
}
 
/** Cleans up all IPC communication of the given task
 *
 *
 */
void ipc_cleanup(task_t *task)
{
    int i;
    call_t *call;
    phone_t *phone;
   
    /* 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 answerbox */
restart_phones:
    spinlock_lock(&task->answerbox.lock);
    while (!list_empty(&task->answerbox.connected_phones)) {
        phone = list_get_instance(task->answerbox.connected_phones.next,
                      phone_t,
                      list);
        if (! spinlock_trylock(&phone->lock)) {
            spinlock_unlock(&task->answerbox.lock);
            goto restart_phones;
        }
       
        /* Disconnect phone */
        phone->callee = NULL;
        list_remove(&phone->list);
 
        spinlock_unlock(&phone->lock);
    }
 
    /* 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 (atomic_get(&task->active_calls)) {
        call = ipc_wait_for_call(&task->answerbox, 0);
        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);
    ipc_irq_make_table(IRQ_COUNT);
}
 
 
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(root)/tags/0.1.1/kernel/generic/src/ipc/ipc.c – Rev 1963 → 1968
