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

  * The structure of a notification message is as follows:
  * - METHOD: method as registered by the SYS_IPC_REGISTER_IRQ syscall
  * - ARG1: payload modified by a 'top-half' handler
  * - ARG2: payload modified by a 'top-half' handler
  * - ARG3: payload modified by a 'top-half' handler
+ * - ARG4: payload modified by a 'top-half' handler
+ * - ARG5: payload modified by a 'top-half' handler
  * - in_phone_hash: interrupt counter (may be needed to assure correct order
  *         in multithreaded drivers)
+ *
+ * Note on synchronization for ipc_irq_register(), ipc_irq_unregister(),
+ * ipc_irq_cleanup() and IRQ handlers:
+ *
+ *   By always taking all of the uspace IRQ hash table lock, IRQ structure lock
+ *   and answerbox lock, we can rule out race conditions between the
+ *   registration functions and also the cleanup function. Thus the observer can
+ *   either see the IRQ structure present in both the hash table and the
+ *   answerbox list or absent in both. Views in which the IRQ structure would be
+ *   linked in the hash table but not in the answerbox list, or vice versa, are
+ *   not possible.
+ *
+ *   By always taking the hash table lock and the IRQ structure lock, we can
+ *   rule out a scenario in which we would free up an IRQ structure, which is
+ *   still referenced by, for example, an IRQ handler. The locking scheme forces
+ *   us to lock the IRQ structure only after any progressing IRQs on that
+ *   structure are finished. Because we hold the hash table lock, we prevent new
+ *   IRQs from taking new references to the IRQ structure.
  */
 #include <arch.h>
 #include <mm/slab.h>
 #include <errno.h>
 #include <ipc/irq.h>
 #include <syscall/copy.h>
 #include <console/console.h>
 #include <print.h>
-/** Execute code associated with IRQ notification.
- *
- * @param call      Notification call.
- * @param code      Top-half pseudocode.
- */
-static void code_execute(call_t *call, irq_code_t *code)
-{
-    unsigned int i;
-    unative_t dstval = 0;
-    if (!code)
-        return;
-    for (i = 0; i < code->cmdcount; i++) {
-        switch (code->cmds[i].cmd) {
-        case CMD_MEM_READ_1:
-            dstval = *((uint8_t *) code->cmds[i].addr);
-            break;
-        case CMD_MEM_READ_2:
-            dstval = *((uint16_t *) code->cmds[i].addr);
-            break;
-        case CMD_MEM_READ_4:
-            dstval = *((uint32_t *) code->cmds[i].addr);
-            break;
-        case CMD_MEM_READ_8:
-            dstval = *((uint64_t *) code->cmds[i].addr);
-            break;
-        case CMD_MEM_WRITE_1:
-            *((uint8_t *) code->cmds[i].addr) = code->cmds[i].value;
-            break;
-        case CMD_MEM_WRITE_2:
-            *((uint16_t *) code->cmds[i].addr) =
-                code->cmds[i].value;
-            break;
-        case CMD_MEM_WRITE_4:
-            *((uint32_t *) code->cmds[i].addr) =
-                code->cmds[i].value;
-            break;
-        case CMD_MEM_WRITE_8:
-            *((uint64_t *) code->cmds[i].addr) =
-                code->cmds[i].value;
-            break;
-#if defined(ia32) || defined(amd64) || defined(ia64)
-        case CMD_PORT_READ_1:
-            dstval = inb((long) code->cmds[i].addr);
-            break;
-        case CMD_PORT_WRITE_1:
-            outb((long) code->cmds[i].addr, code->cmds[i].value);
-            break;
-#endif
-#if defined(ia64) && defined(SKI)
-        case CMD_IA64_GETCHAR:
-            dstval = _getc(&ski_uconsole);
-            break;
-#endif
-#if defined(ppc32)
-        case CMD_PPC32_GETCHAR:
-            dstval = cuda_get_scancode();
-            break;
-#endif
-        default:
-            break;
-        }
-        if (code->cmds[i].dstarg && code->cmds[i].dstarg <
-            IPC_CALL_LEN) {
-            call->data.args[code->cmds[i].dstarg] = dstval;
-        }
-    }
-}
-/** Free top-half pseudocode.
+/** Free the top-half pseudocode.
+ *
  * @param code      Pointer to the top-half pseudocode.
  */
 static void code_free(irq_code_t *code)
+{
         free(code->cmds);
         free(code);
+    }
+}
-/** Copy top-half pseudocode from userspace into the kernel.
+/** Copy the top-half pseudocode from userspace into the kernel.
+ *
  * @param ucode     Userspace address of the top-half pseudocode.
+ *
  * @return      Kernel address of the copied pseudocode.
  */
+    }
     return code;
+}
-/** Unregister task from IRQ notification.
- *
- * @param box       Answerbox associated with the notification.
- * @param inr       IRQ number.
- * @param devno     Device number.
- */
-void ipc_irq_unregister(answerbox_t *box, inr_t inr, devno_t devno)
-{
-    ipl_t ipl;
-    irq_t *irq;
-    ipl = interrupts_disable();
-    irq = irq_find_and_lock(inr, devno);
-    if (irq) {
-        if (irq->notif_cfg.answerbox == box) {
-            code_free(irq->notif_cfg.code);
-            irq->notif_cfg.notify = false;
-            irq->notif_cfg.answerbox = NULL;
-            irq->notif_cfg.code = NULL;
-            irq->notif_cfg.method = 0;
-            irq->notif_cfg.counter = 0;
-            spinlock_lock(&box->irq_lock);
-            list_remove(&irq->notif_cfg.link);
-            spinlock_unlock(&box->irq_lock);
-            spinlock_unlock(&irq->lock);
-        }
-    }
-    interrupts_restore(ipl);
-}
 /** Register an answerbox as a receiving end for IRQ notifications.
+ *
- * @param box       Receiving answerbox.
+ * @param box    Receiving answerbox.
- * @param inr       IRQ number.
+ * @param inr    IRQ number.
- * @param devno     Device number.
+ * @param devno  Device number.
- * @param method    Method to be associated with the notification.
+ * @param method Method to be associated with the notification.
- * @param ucode     Uspace pointer to top-half pseudocode.
+ * @param ucode  Uspace pointer to top-half pseudocode.
+ *
+ * @return EBADMEM, ENOENT or EEXISTS on failure or 0 on success.
+ *
- * @return      EBADMEM, ENOENT or EEXISTS on failure or 0 on success.
  */
 int ipc_irq_register(answerbox_t *box, inr_t inr, devno_t devno,
     unative_t method, irq_code_t *ucode)
+{
     ipl_t ipl;
     irq_code_t *code;
     irq_t *irq;
+    link_t *hlp;
+    unative_t key[] = {
+        (unative_t) inr,
+        (unative_t) devno
+    };
     if (ucode) {
         code = code_from_uspace(ucode);
         if (!code)
             return EBADMEM;
     } else {
         code = NULL;
+    }
-    ipl = interrupts_disable();
-    irq = irq_find_and_lock(inr, devno);
-    if (!irq) {
-        interrupts_restore(ipl);
-        code_free(code);
-        return ENOENT;
-    }
-    if (irq->notif_cfg.answerbox) {
-        spinlock_unlock(&irq->lock);
-        interrupts_restore(ipl);
-        code_free(code);
-        return EEXISTS;
-    }
+    /*
+     * Allocate and populate the IRQ structure.
+     */
+    irq = malloc(sizeof(irq_t), 0);
+    irq_initialize(irq);
+    irq->devno = devno;
+    irq->inr = inr;
+    irq->claim = ipc_irq_top_half_claim;
+    irq->handler = ipc_irq_top_half_handler;
     irq->notif_cfg.notify = true;
     irq->notif_cfg.answerbox = box;
     irq->notif_cfg.method = method;
     irq->notif_cfg.code = code;
     irq->notif_cfg.counter = 0;
+    /*
+     * Enlist the IRQ structure in the uspace IRQ hash table and the
+     * answerbox's list.
+     */
+    ipl = interrupts_disable();
+    spinlock_lock(&irq_uspace_hash_table_lock);
+    hlp = hash_table_find(&irq_uspace_hash_table, key);
+    if (hlp) {
+        irq_t *hirq __attribute__((unused))
+            = hash_table_get_instance(hlp, irq_t, link);
+        /* hirq is locked */
+        spinlock_unlock(&hirq->lock);
+        code_free(code);
+        spinlock_unlock(&irq_uspace_hash_table_lock);
+        free(irq);
+        interrupts_restore(ipl);
+        return EEXISTS;
+    }
+    spinlock_lock(&irq->lock);  /* Not really necessary, but paranoid */
     spinlock_lock(&box->irq_lock);
+    hash_table_insert(&irq_uspace_hash_table, key, &irq->link);
     list_append(&irq->notif_cfg.link, &box->irq_head);
     spinlock_unlock(&box->irq_lock);
+    spinlock_unlock(&irq->lock);
+    spinlock_unlock(&irq_uspace_hash_table_lock);
+    interrupts_restore(ipl);
+    return EOK;
+}
+/** Unregister task from IRQ notification.
+ *
+ * @param box       Answerbox associated with the notification.
+ * @param inr       IRQ number.
+ * @param devno     Device number.
+ */
+int ipc_irq_unregister(answerbox_t *box, inr_t inr, devno_t devno)
+{
+    ipl_t ipl;
+    unative_t key[] = {
+        (unative_t) inr,
+        (unative_t) devno
+    };
+    link_t *lnk;
+    irq_t *irq;
+    ipl = interrupts_disable();
+    spinlock_lock(&irq_uspace_hash_table_lock);
+    lnk = hash_table_find(&irq_uspace_hash_table, key);
+    if (!lnk) {
+        spinlock_unlock(&irq_uspace_hash_table_lock);
+        interrupts_restore(ipl);
+        return ENOENT;
+    }
+    irq = hash_table_get_instance(lnk, irq_t, link);
+    /* irq is locked */
+    spinlock_lock(&box->irq_lock);
+    ASSERT(irq->notif_cfg.answerbox == box);
+    /* Free up the pseudo code and associated structures. */
+    code_free(irq->notif_cfg.code);
+    /* Remove the IRQ from the answerbox's list. */
+    list_remove(&irq->notif_cfg.link);
+    /*
+     * We need to drop the IRQ lock now because hash_table_remove() will try
+     * to reacquire it. That basically violates the natural locking order,
+     * but a deadlock in hash_table_remove() is prevented by the fact that
+     * we already held the IRQ lock and didn't drop the hash table lock in
+     * the meantime.
+     */
     spinlock_unlock(&irq->lock);
+    /* Remove the IRQ from the uspace IRQ hash table. */
+    hash_table_remove(&irq_uspace_hash_table, key, 2);
+    spinlock_unlock(&irq_uspace_hash_table_lock);
+    spinlock_unlock(&box->irq_lock);
+    /* Free up the IRQ structure. */
+    free(irq);
     interrupts_restore(ipl);
+    return EOK;
+}
+/** Disconnect all IRQ notifications from an answerbox.
+ *
+ * This function is effective because the answerbox contains
+ * list of all irq_t structures that are registered to
+ * send notifications to it.
+ *
+ * @param box       Answerbox for which we want to carry out the cleanup.
+ */
+void ipc_irq_cleanup(answerbox_t *box)
+{
+    ipl_t ipl;
+loop:
+    ipl = interrupts_disable();
+    spinlock_lock(&irq_uspace_hash_table_lock);
+    spinlock_lock(&box->irq_lock);
+    while (box->irq_head.next != &box->irq_head) {
+        link_t *cur = box->irq_head.next;
+        irq_t *irq;
+        DEADLOCK_PROBE_INIT(p_irqlock);
+        unative_t key[2];
+        irq = list_get_instance(cur, irq_t, notif_cfg.link);
+        if (!spinlock_trylock(&irq->lock)) {
+            /*
+             * Avoid deadlock by trying again.
+             */
+            spinlock_unlock(&box->irq_lock);
+            spinlock_unlock(&irq_uspace_hash_table_lock);
+            interrupts_restore(ipl);
+            DEADLOCK_PROBE(p_irqlock, DEADLOCK_THRESHOLD);
+            goto loop;
+        }
+        key[0] = irq->inr;
+        key[1] = irq->devno;
+        ASSERT(irq->notif_cfg.answerbox == box);
+        /* Unlist from the answerbox. */
+        list_remove(&irq->notif_cfg.link);
+        /* Free up the pseudo code and associated structures. */
+        code_free(irq->notif_cfg.code);
+        /*
+         * We need to drop the IRQ lock now because hash_table_remove()
+         * will try to reacquire it. That basically violates the natural
+         * locking order, but a deadlock in hash_table_remove() is
+         * prevented by the fact that we already held the IRQ lock and
+         * didn't drop the hash table lock in the meantime.
+         */
+        spinlock_unlock(&irq->lock);
+        /* Remove from the hash table. */
+        hash_table_remove(&irq_uspace_hash_table, key, 2);
-    return 0;
+        free(irq);
+    }
+    spinlock_unlock(&box->irq_lock);
+    spinlock_unlock(&irq_uspace_hash_table_lock);
+    interrupts_restore(ipl);
+}
 /** Add a call to the proper answerbox queue.
+ *
  * Assume irq->lock is locked.
     spinlock_unlock(&irq->notif_cfg.answerbox->irq_lock);
     waitq_wakeup(&irq->notif_cfg.answerbox->wq, WAKEUP_FIRST);
+}
-/** Send notification message.
+/** Apply the top-half pseudo code to find out whether to accept the IRQ or not.
+ *
  * @param irq       IRQ structure.
- * @param a1        Driver-specific payload argument.
+ *
- * @param a2        Driver-specific payload argument.
+ * @return      IRQ_ACCEPT if the interrupt is accepted by the
- * @param a3        Driver-specific payload argument.
+ *          pseudocode. IRQ_DECLINE otherwise.
- * @param a4        Driver-specific payload argument.
- * @param a5        Driver-specific payload argument.
  */
-void ipc_irq_send_msg(irq_t *irq, unative_t a1, unative_t a2, unative_t a3,
+irq_ownership_t ipc_irq_top_half_claim(irq_t *irq)
-    unative_t a4, unative_t a5)
+{
+    unsigned int i;
-    call_t *call;
+    unative_t dstval;
-    spinlock_lock(&irq->lock);
+    irq_code_t *code = irq->notif_cfg.code;
+    unative_t *scratch = irq->notif_cfg.scratch;
-    if (irq->notif_cfg.answerbox) {
+    if (!irq->notif_cfg.notify)
-        call = ipc_call_alloc(FRAME_ATOMIC);
+        return IRQ_DECLINE;
-        if (!call) {
+    if (!code)
-            spinlock_unlock(&irq->lock);
-            return;
+        return IRQ_DECLINE;
-        }
-        call->flags |= IPC_CALL_NOTIF;
-        IPC_SET_METHOD(call->data, irq->notif_cfg.method);
-        IPC_SET_ARG1(call->data, a1);
-        IPC_SET_ARG2(call->data, a2);
-        IPC_SET_ARG3(call->data, a3);
-        IPC_SET_ARG4(call->data, a4);
-        IPC_SET_ARG5(call->data, a5);
+    for (i = 0; i < code->cmdcount; i++) {
-        /* Put a counter to the message */
+        unsigned int srcarg = code->cmds[i].srcarg;
-        call->priv = ++irq->notif_cfg.counter;
+        unsigned int dstarg = code->cmds[i].dstarg;
+        if (srcarg >= IPC_CALL_LEN)
+            break;
+        if (dstarg >= IPC_CALL_LEN)
+            break;
+        switch (code->cmds[i].cmd) {
+        case CMD_PIO_READ_8:
+            dstval = pio_read_8((ioport8_t *) code->cmds[i].addr);
+            if (dstarg)
+                scratch[dstarg] = dstval;
+            break;
+        case CMD_PIO_READ_16:
+            dstval = pio_read_16((ioport16_t *) code->cmds[i].addr);
+            if (dstarg)
+                scratch[dstarg] = dstval;
+            break;
+        case CMD_PIO_READ_32:
+            dstval = pio_read_32((ioport32_t *) code->cmds[i].addr);
+            if (dstarg)
+                scratch[dstarg] = dstval;
+            break;
+        case CMD_PIO_WRITE_8:
+            pio_write_8((ioport8_t *) code->cmds[i].addr,
+                (uint8_t) code->cmds[i].value);
+            break;
+        case CMD_PIO_WRITE_16:
+            pio_write_16((ioport16_t *) code->cmds[i].addr,
+                (uint16_t) code->cmds[i].value);
+            break;
+        case CMD_PIO_WRITE_32:
+            pio_write_32((ioport32_t *) code->cmds[i].addr,
+                (uint32_t) code->cmds[i].value);
+            break;
+        case CMD_BTEST:
-        send_call(irq, call);
+            if (srcarg && dstarg) {
+                dstval = scratch[srcarg] & code->cmds[i].value;
+                scratch[dstarg] = dstval;
+            }
+            break;
+        case CMD_PREDICATE:
+            if (srcarg && !scratch[srcarg]) {
+                i += code->cmds[i].value;
+                continue;
+            }
+            break;
+        case CMD_ACCEPT:
+            return IRQ_ACCEPT;
+            break;
+        case CMD_DECLINE:
+        default:
+            return IRQ_DECLINE;
+        }
+    }
-    spinlock_unlock(&irq->lock);
+    return IRQ_DECLINE;
+}
-/** Notify a task that an IRQ had occurred.
+/* IRQ top-half handler.
+ *
  * We expect interrupts to be disabled and the irq->lock already held.
+ *
  * @param irq       IRQ structure.
  */
-void ipc_irq_send_notif(irq_t *irq)
+void ipc_irq_top_half_handler(irq_t *irq)
+{
-    call_t *call;
     ASSERT(irq);
     if (irq->notif_cfg.answerbox) {
+        call_t *call;
         call = ipc_call_alloc(FRAME_ATOMIC);
-        if (!call) {
+        if (!call)
             return;
-        }
         call->flags |= IPC_CALL_NOTIF;
         /* Put a counter to the message */
         call->priv = ++irq->notif_cfg.counter;
         /* Set up args */
         IPC_SET_METHOD(call->data, irq->notif_cfg.method);
+        IPC_SET_ARG1(call->data, irq->notif_cfg.scratch[1]);
+        IPC_SET_ARG2(call->data, irq->notif_cfg.scratch[2]);
+        IPC_SET_ARG3(call->data, irq->notif_cfg.scratch[3]);
+        IPC_SET_ARG4(call->data, irq->notif_cfg.scratch[4]);
+        IPC_SET_ARG5(call->data, irq->notif_cfg.scratch[5]);
-        /* Execute code to handle irq */
-        code_execute(call, irq->notif_cfg.code);
         send_call(irq, call);
+    }
+}
-/** Disconnect all IRQ notifications from an answerbox.
- *
- * This function is effective because the answerbox contains
- * list of all irq_t structures that are registered to
- * send notifications to it.
+/** Send notification message.
+ *
+ * @param irq       IRQ structure.
+ * @param a1        Driver-specific payload argument.
+ * @param a2        Driver-specific payload argument.
- * @param box       Answerbox for which we want to carry out the cleanup.
+ * @param a3        Driver-specific payload argument.
+ * @param a4        Driver-specific payload argument.
+ * @param a5        Driver-specific payload argument.
  */
+void ipc_irq_send_msg(irq_t *irq, unative_t a1, unative_t a2, unative_t a3,
-void ipc_irq_cleanup(answerbox_t *box)
+    unative_t a4, unative_t a5)
+{
-    ipl_t ipl;
+    call_t *call;
-loop:
-    ipl = interrupts_disable();
-    spinlock_lock(&box->irq_lock);
+    spinlock_lock(&irq->lock);
-    while (box->irq_head.next != &box->irq_head) {
+    if (irq->notif_cfg.answerbox) {
-        link_t *cur = box->irq_head.next;
+        call = ipc_call_alloc(FRAME_ATOMIC);
-        irq_t *irq;
+        if (!call) {
-        DEADLOCK_PROBE_INIT(p_irqlock);
-        irq = list_get_instance(cur, irq_t, notif_cfg.link);
-        if (!spinlock_trylock(&irq->lock)) {
-            /*
-             * Avoid deadlock by trying again.
-             */
-            spinlock_unlock(&box->irq_lock);
+            spinlock_unlock(&irq->lock);
-            interrupts_restore(ipl);
-            DEADLOCK_PROBE(p_irqlock, DEADLOCK_THRESHOLD);
-            goto loop;
+            return;
+        }
-        ASSERT(irq->notif_cfg.answerbox == box);
-        list_remove(&irq->notif_cfg.link);
+        call->flags |= IPC_CALL_NOTIF;
-        /*
-         * Don't forget to free any top-half pseudocode.
+        /* Put a counter to the message */
-         */
-        code_free(irq->notif_cfg.code);
+        call->priv = ++irq->notif_cfg.counter;
-        irq->notif_cfg.notify = false;
-        irq->notif_cfg.answerbox = NULL;
-        irq->notif_cfg.code = NULL;
-        irq->notif_cfg.method = 0;
-        irq->notif_cfg.counter = 0;
+        IPC_SET_METHOD(call->data, irq->notif_cfg.method);
+        IPC_SET_ARG1(call->data, a1);
+        IPC_SET_ARG2(call->data, a2);
+        IPC_SET_ARG3(call->data, a3);
+        IPC_SET_ARG4(call->data, a4);
+        IPC_SET_ARG5(call->data, a5);
-        spinlock_unlock(&irq->lock);
+        send_call(irq, call);
+    }
-    spinlock_unlock(&box->irq_lock);
+    spinlock_unlock(&irq->lock);
-    interrupts_restore(ipl);
+}
 /** @}
  */

Subversion Repositories HelenOS

(root)//branches/tracing/kernel/generic/src/ipc/irq.c – Rev 3675 → 4377