WebSVN – HelenOS-historic – Diff – /kernel/trunk/generic/src/syscall/syscall.c

 /*
  * Copyright (C) 2005 Martin Decky
  * 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.
  */
 #include <syscall/syscall.h>
 #include <proc/thread.h>
 #include <mm/as.h>
 #include <print.h>
 #include <putchar.h>
 #include <ipc/ipc.h>
 #include <errno.h>
 #include <proc/task.h>
 #include <arch.h>
 #include <debug.h>
 static __native sys_ctl(void) {
     printf("Thread finished\n");
     thread_exit();
     /* Unreachable */
     return 0;
+}
 static __native sys_io(int fd, const void * buf, size_t count) {
     // TODO: buf sanity checks and a lot of other stuff ...
     size_t i;
     for (i = 0; i < count; i++)
         putchar(((char *) buf)[i]);
     return count;
+}
+static phone_t * get_phone(__native phoneid)
+{
+    phone_t *phone;
+    if (phoneid >= IPC_MAX_PHONES)
+        return NULL;
+    phone = &TASK->phones[phoneid];
+    if (!phone->callee)
+        return NULL;
+    return phone;
+}
 /** Send a call over IPC, wait for reply, return to user
+ *
  * @return Call identification, returns -1 on fatal error,
            -2 on 'Too many async request, handle answers first
  */
-static __native sys_ipc_call_sync(__native phoneid, __native method,
+static __native sys_ipc_call_sync_fast(__native phoneid, __native method,
-                   __native arg1, __native *data)
+                       __native arg1, __native *data)
+{
     call_t call;
     phone_t *phone;
     /* Special answerbox for synchronous messages */
-    if (phoneid >= IPC_MAX_PHONES)
-        return IPC_CALLRET_FATAL;
-    phone = &TASK->phones[phoneid];
+    phone = get_phone(phoneid);
-    if (!phone->callee)
+    if (!phone)
         return IPC_CALLRET_FATAL;
     ipc_call_init(&call);
     IPC_SET_METHOD(call.data, method);
     IPC_SET_ARG1(call.data, arg1);
     ipc_call_sync(phone, &call);
     copy_to_uspace(data, &call.data, sizeof(call.data));
     return 0;
+}
+/** Synchronous IPC call allowing to send whole message */
-static __native sys_ipc_call_sync_medium(__native phoneid, __native *data)
+static __native sys_ipc_call_sync(__native phoneid, __native *data)
+{
     call_t call;
     phone_t *phone;
     /* Special answerbox for synchronous messages */
-    if (phoneid >= IPC_MAX_PHONES)
-        return IPC_CALLRET_FATAL;
-    phone = &TASK->phones[phoneid];
+    phone = get_phone(phoneid);
-    if (!phone->callee)
+    if (!phone)
         return IPC_CALLRET_FATAL;
     ipc_call_init(&call);
     copy_from_uspace(&call.data, data, sizeof(call.data));
     ipc_call_sync(phone, &call);
     copy_to_uspace(data, &call.data, sizeof(call.data));
     return 0;
+}
+/** Check that the task did not exceed allowed limit
+ *
+ * @return 0 - Limit OK,   -1 - limit exceeded
+ */
+static int check_call_limit(void)
+{
+    if (atomic_inc_post(&TASK->active_calls) > IPC_MAX_ASYNC_CALLS) {
+        atomic_dec(&TASK->active_calls);
+        return -1;
+    }
+    return 0;
+}
 /** Send an asynchronous call over ipc
+ *
  * @return Call identification, returns -1 on fatal error,
            -2 on 'Too many async request, handle answers first
  */
-static __native sys_ipc_call_async(__native phoneid, __native method,
+static __native sys_ipc_call_async_fast(__native phoneid, __native method,
-                   __native arg1, __native arg2)
+                    __native arg1, __native arg2)
+{
     call_t *call;
     phone_t *phone;
-    if (phoneid >= IPC_MAX_PHONES)
+    phone = get_phone(phoneid);
+    if (!phone)
         return IPC_CALLRET_FATAL;
-    phone = &TASK->phones[phoneid];
-    if (!phone->callee)
+    if (check_call_limit())
-        return IPC_CALLRET_FATAL;
+        return IPC_CALLRET_TEMPORARY;
-    /* TODO: Check that we did not exceed system imposed maximum
-     * of asynchrnously sent messages
-     * - the userspace should be able to handle it correctly
-     */
     call = ipc_call_alloc();
     IPC_SET_METHOD(call->data, method);
     IPC_SET_ARG1(call->data, arg1);
     IPC_SET_ARG2(call->data, arg2);
     ipc_call(phone, call);
     return (__native) call;
+}
+/** Synchronous IPC call allowing to send whole message
+ *
+ * @return The same as sys_ipc_call_async
+ */
+static __native sys_ipc_call_async(__native phoneid, __native *data)
+{
+    call_t *call;
+    phone_t *phone;
+    phone = get_phone(phoneid);
+    if (!phone)
+        return IPC_CALLRET_FATAL;
+    if (check_call_limit())
+        return IPC_CALLRET_TEMPORARY;
+    call = ipc_call_alloc();
+    copy_from_uspace(&call->data, data, sizeof(call->data));
+    ipc_call(phone, call);
+    return (__native) call;
+}
 /** Send IPC answer */
 static __native sys_ipc_answer(__native callid, __native retval, __native arg1,
                    __native arg2)
+{
     call_t *call;
     /* Check that the user is not sending us answer callid */
     ASSERT(! (callid & 1));
     /* TODO: Check that the callid is in the dispatch table */
     call = (call_t *) callid;
     IPC_SET_RETVAL(call->data, retval);
     IPC_SET_ARG1(call->data, arg1);
     IPC_SET_ARG2(call->data, arg2);
     ipc_answer(&TASK->answerbox, call);
     return 0;
+}
 /** Wait for incoming ipc call or answer
+ *
  * @param result
  * @param flags
  * @return Callid, if callid & 1, then the call is answer
  */
 static __native sys_ipc_wait_for_call(__native *calldata, __native flags)
+{
     call_t *call;
     call = ipc_wait_for_call(&TASK->answerbox, flags);
     copy_to_uspace(calldata, &call->data, sizeof(call->data));
     if (call->flags & IPC_CALL_ANSWERED) {
         ASSERT(! (call->flags & IPC_CALL_STATIC_ALLOC));
         ipc_call_free(call);
+        atomic_dec(&TASK->active_calls);
         return ((__native)call) | IPC_CALLID_ANSWERED;
+    }
     return (__native)call;
+}
 static __native sys_mremap(void *address, size_t size, unsigned long flags)
+{
     return as_remap(AS, (__address) address, size, 0);
+}
 syshandler_t syscall_table[SYSCALL_END] = {
     sys_ctl,
     sys_io,
     sys_mremap,
+    sys_ipc_call_sync_fast,
     sys_ipc_call_sync,
-    sys_ipc_call_sync_medium,
+    sys_ipc_call_async_fast,
     sys_ipc_call_async,
     sys_ipc_answer,
     sys_ipc_wait_for_call
 };

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/generic/src/syscall/syscall.c – Rev 977 → 998