WebSVN – HelenOS – Diff – /trunk/kernel/generic/src/proc/thread.c

 /*
  * Copyright (c) 2001-2004 Jakub Jermar
  * 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 genericproc
  * @{
  */
 /**
  * @file
  * @brief   Thread management functions.
  */
 #include <proc/scheduler.h>
 #include <proc/thread.h>
 #include <proc/task.h>
 #include <proc/uarg.h>
 #include <mm/frame.h>
 #include <mm/page.h>
 #include <arch/asm.h>
 #include <arch/cycle.h>
 #include <arch.h>
 #include <synch/synch.h>
 #include <synch/spinlock.h>
 #include <synch/waitq.h>
 #include <synch/rwlock.h>
 #include <cpu.h>
 #include <func.h>
 #include <context.h>
 #include <adt/btree.h>
 #include <adt/list.h>
 #include <time/clock.h>
 #include <time/timeout.h>
 #include <config.h>
 #include <arch/interrupt.h>
 #include <smp/ipi.h>
 #include <arch/faddr.h>
 #include <atomic.h>
 #include <memstr.h>
 #include <print.h>
 #include <mm/slab.h>
 #include <debug.h>
 #include <main/uinit.h>
 #include <syscall/copy.h>
 #include <errno.h>
 /** Thread states */
 char *thread_states[] = {
     "Invalid",
     "Running",
     "Sleeping",
     "Ready",
     "Entering",
     "Exiting",
     "Undead"
 };
 /** Lock protecting the threads_btree B+tree.
+ *
  * For locking rules, see declaration thereof.
  */
 SPINLOCK_INITIALIZE(threads_lock);
 /** B+tree of all threads.
+ *
  * When a thread is found in the threads_btree B+tree, it is guaranteed to
  * exist as long as the threads_lock is held.
  */
 btree_t threads_btree;
 SPINLOCK_INITIALIZE(tidlock);
 thread_id_t last_tid = 0;
 static slab_cache_t *thread_slab;
 #ifdef ARCH_HAS_FPU
 slab_cache_t *fpu_context_slab;
 #endif
 /** Thread wrapper.
+ *
  * This wrapper is provided to ensure that every thread makes a call to
  * thread_exit() when its implementing function returns.
+ *
  * interrupts_disable() is assumed.
+ *
  */
 static void cushion(void)
+{
     void (*f)(void *) = THREAD->thread_code;
     void *arg = THREAD->thread_arg;
     THREAD->last_cycle = get_cycle();
     /* This is where each thread wakes up after its creation */
     spinlock_unlock(&THREAD->lock);
     interrupts_enable();
     f(arg);
     /* Accumulate accounting to the task */
     ipl_t ipl = interrupts_disable();
     spinlock_lock(&THREAD->lock);
     if (!THREAD->uncounted) {
         thread_update_accounting();
         uint64_t cycles = THREAD->cycles;
         THREAD->cycles = 0;
         spinlock_unlock(&THREAD->lock);
         spinlock_lock(&TASK->lock);
         TASK->cycles += cycles;
         spinlock_unlock(&TASK->lock);
     } else
         spinlock_unlock(&THREAD->lock);
     interrupts_restore(ipl);
     thread_exit();
     /* not reached */
+}
 /** Initialization and allocation for thread_t structure */
 static int thr_constructor(void *obj, int kmflags)
+{
     thread_t *t = (thread_t *) obj;
     spinlock_initialize(&t->lock, "thread_t_lock");
     link_initialize(&t->rq_link);
     link_initialize(&t->wq_link);
     link_initialize(&t->th_link);
     /* call the architecture-specific part of the constructor */
     thr_constructor_arch(t);
 #ifdef ARCH_HAS_FPU
-#  ifdef CONFIG_FPU_LAZY
+#ifdef CONFIG_FPU_LAZY
     t->saved_fpu_context = NULL;
-#  else
+#else
-    t->saved_fpu_context = slab_alloc(fpu_context_slab,kmflags);
+    t->saved_fpu_context = slab_alloc(fpu_context_slab, kmflags);
     if (!t->saved_fpu_context)
         return -1;
-#  endif
+#endif
 #endif
     t->kstack = (uint8_t *) frame_alloc(STACK_FRAMES, FRAME_KA | kmflags);
-    if (! t->kstack) {
+    if (!t->kstack) {
 #ifdef ARCH_HAS_FPU
         if (t->saved_fpu_context)
-            slab_free(fpu_context_slab,t->saved_fpu_context);
+            slab_free(fpu_context_slab, t->saved_fpu_context);
 #endif
         return -1;
+    }
     return 0;
+}
 /** Destruction of thread_t object */
 static int thr_destructor(void *obj)
+{
     thread_t *t = (thread_t *) obj;
     /* call the architecture-specific part of the destructor */
     thr_destructor_arch(t);
     frame_free(KA2PA(t->kstack));
 #ifdef ARCH_HAS_FPU
     if (t->saved_fpu_context)
-        slab_free(fpu_context_slab,t->saved_fpu_context);
+        slab_free(fpu_context_slab, t->saved_fpu_context);
 #endif
     return 1; /* One page freed */
+}
 /** Initialize threads
+ *
  * Initialize kernel threads support.
+ *
  */
 void thread_init(void)
+{
     THREAD = NULL;
     atomic_set(&nrdy,0);
     thread_slab = slab_cache_create("thread_slab", sizeof(thread_t), 0,
         thr_constructor, thr_destructor, 0);
 #ifdef ARCH_HAS_FPU
     fpu_context_slab = slab_cache_create("fpu_slab", sizeof(fpu_context_t),
         FPU_CONTEXT_ALIGN, NULL, NULL, 0);
 #endif
     btree_create(&threads_btree);
+}
 /** Make thread ready
+ *
  * Switch thread t to the ready state.
+ *
  * @param t Thread to make ready.
+ *
  */
 void thread_ready(thread_t *t)
+{
     cpu_t *cpu;
     runq_t *r;
     ipl_t ipl;
     int i, avg;
     ipl = interrupts_disable();
     spinlock_lock(&t->lock);
-    ASSERT(! (t->state == Ready));
+    ASSERT(!(t->state == Ready));
     i = (t->priority < RQ_COUNT - 1) ? ++t->priority : t->priority;
     cpu = CPU;
     if (t->flags & THREAD_FLAG_WIRED) {
         ASSERT(t->cpu != NULL);
         cpu = t->cpu;
+    }
     t->state = Ready;
     spinlock_unlock(&t->lock);
     /*
      * Append t to respective ready queue on respective processor.
      */
     r = &cpu->rq[i];
     spinlock_lock(&r->lock);
     list_append(&t->rq_link, &r->rq_head);
     r->n++;
     spinlock_unlock(&r->lock);
     atomic_inc(&nrdy);
     avg = atomic_get(&nrdy) / config.cpu_active;
     atomic_inc(&cpu->nrdy);
     interrupts_restore(ipl);
+}
-/** Destroy thread memory structure
- *
- * Detach thread from all queues, cpus etc. and destroy it.
- *
- * Assume thread->lock is held!!
- */
-void thread_destroy(thread_t *t)
-{
-    bool destroy_task = false;
-    ASSERT(t->state == Exiting || t->state == Undead);
-    ASSERT(t->task);
-    ASSERT(t->cpu);
-    spinlock_lock(&t->cpu->lock);
-    if(t->cpu->fpu_owner == t)
-        t->cpu->fpu_owner = NULL;
-    spinlock_unlock(&t->cpu->lock);
-    spinlock_unlock(&t->lock);
-    spinlock_lock(&threads_lock);
-    btree_remove(&threads_btree, (btree_key_t) ((uintptr_t ) t), NULL);
-    spinlock_unlock(&threads_lock);
-    /*
-     * Detach from the containing task.
-     */
-    spinlock_lock(&t->task->lock);
-    list_remove(&t->th_link);
-    if (--t->task->refcount == 0) {
-        t->task->accept_new_threads = false;
-        destroy_task = true;
-    }
-    spinlock_unlock(&t->task->lock);
-    if (destroy_task)
-        task_destroy(t->task);
-    /*
-     * If the thread had a userspace context, free up its kernel_uarg
-     * structure.
-     */
-    if (t->flags & THREAD_FLAG_USPACE) {
-        ASSERT(t->thread_arg);
-        free(t->thread_arg);
-    }
-    slab_free(thread_slab, t);
-}
 /** Create new thread
+ *
  * Create a new thread.
+ *
  * @param func      Thread's implementing function.
  * @param arg       Thread's implementing function argument.
  * @param task      Task to which the thread belongs.
  * @param flags     Thread flags.
  * @param name      Symbolic name.
  * @param uncounted Thread's accounting doesn't affect accumulated task
  *          accounting.
+ *
  * @return New thread's structure on success, NULL on failure.
+ *
  */
 thread_t *thread_create(void (* func)(void *), void *arg, task_t *task,
     int flags, char *name, bool uncounted)
+{
     thread_t *t;
     ipl_t ipl;
     t = (thread_t *) slab_alloc(thread_slab, 0);
     if (!t)
         return NULL;
     /* Not needed, but good for debugging */
     memsetb((uintptr_t) t->kstack, THREAD_STACK_SIZE * 1 << STACK_FRAMES,
 );
     ipl = interrupts_disable();
     spinlock_lock(&tidlock);
     t->tid = ++last_tid;
     spinlock_unlock(&tidlock);
     interrupts_restore(ipl);
     context_save(&t->saved_context);
     context_set(&t->saved_context, FADDR(cushion), (uintptr_t) t->kstack,
         THREAD_STACK_SIZE);
     the_initialize((the_t *) t->kstack);
     ipl = interrupts_disable();
     t->saved_context.ipl = interrupts_read();
     interrupts_restore(ipl);
     memcpy(t->name, name, THREAD_NAME_BUFLEN);
     t->thread_code = func;
     t->thread_arg = arg;
     t->ticks = -1;
     t->cycles = 0;
     t->uncounted = uncounted;
     t->priority = -1;       /* start in rq[0] */
     t->cpu = NULL;
     t->flags = flags;
     t->state = Entering;
     t->call_me = NULL;
     t->call_me_with = NULL;
     timeout_initialize(&t->sleep_timeout);
     t->sleep_interruptible = false;
     t->sleep_queue = NULL;
     t->timeout_pending = 0;
     t->in_copy_from_uspace = false;
     t->in_copy_to_uspace = false;
     t->interrupted = false;
     t->join_type = None;
     t->detached = false;
     waitq_initialize(&t->join_wq);
     t->rwlock_holder_type = RWLOCK_NONE;
     t->task = task;
     t->fpu_context_exists = 0;
     t->fpu_context_engaged = 0;
     /* might depend on previous initialization */
     thread_create_arch(t);
-    /*
-     * Attach to the containing task.
-     */
     ipl = interrupts_disable();
     spinlock_lock(&task->lock);
     if (!task->accept_new_threads) {
         spinlock_unlock(&task->lock);
         slab_free(thread_slab, t);
         interrupts_restore(ipl);
         return NULL;
+    } else {
+        /*
+         * Bump the reference count so that this task cannot be
+         * destroyed while the new thread is being attached to it.
+         */
+        task->refcount++;
+    }
+    spinlock_unlock(&task->lock);
+    interrupts_restore(ipl);
+    if (!(flags & THREAD_FLAG_NOATTACH))
+        thread_attach(t, task);
+    return t;
+}
+/** Destroy thread memory structure
+ *
+ * Detach thread from all queues, cpus etc. and destroy it.
+ *
+ * Assume thread->lock is held!!
+ */
+void thread_destroy(thread_t *t)
+{
+    bool destroy_task = false;
+    ASSERT(t->state == Exiting || t->state == Undead);
+    ASSERT(t->task);
+    ASSERT(t->cpu);
+    spinlock_lock(&t->cpu->lock);
+    if (t->cpu->fpu_owner == t)
+        t->cpu->fpu_owner = NULL;
+    spinlock_unlock(&t->cpu->lock);
+    spinlock_unlock(&t->lock);
+    spinlock_lock(&threads_lock);
+    btree_remove(&threads_btree, (btree_key_t) ((uintptr_t ) t), NULL);
+    spinlock_unlock(&threads_lock);
+    /*
+     * Detach from the containing task.
+     */
+    spinlock_lock(&t->task->lock);
+    list_remove(&t->th_link);
+    if (--t->task->refcount == 0) {
+        t->task->accept_new_threads = false;
+        destroy_task = true;
+    }
+    spinlock_unlock(&t->task->lock);
+    if (destroy_task)
+        task_destroy(t->task);
+    /*
+     * If the thread had a userspace context, free up its kernel_uarg
+     * structure.
+     */
+    if (t->flags & THREAD_FLAG_USPACE) {
+        ASSERT(t->thread_arg);
+        free(t->thread_arg);
+    }
+    slab_free(thread_slab, t);
+}
+/** Make the thread visible to the system.
+ *
+ * Attach the thread structure to the current task and make it visible in the
+ * threads_btree.
+ *
+ * @param t Thread to be attached to the task.
+ * @param task  Task to which the thread is to be attached.
+ */
+void thread_attach(thread_t *t, task_t *task)
+{
+    ipl_t ipl;
+    /*
+     * Attach to the current task.
+     */
+    ipl = interrupts_disable();
+    spinlock_lock(&task->lock);
+    ASSERT(task->refcount);
     list_append(&t->th_link, &task->th_head);
-    if (task->refcount++ == 0)
+    if (task->refcount == 1)
         task->main_thread = t;
     spinlock_unlock(&task->lock);
     /*
      * Register this thread in the system-wide list.
      */
     spinlock_lock(&threads_lock);
     btree_insert(&threads_btree, (btree_key_t) ((uintptr_t) t), (void *) t,
         NULL);
     spinlock_unlock(&threads_lock);
     interrupts_restore(ipl);
-    return t;
+}
 /** Terminate thread.
+ *
  * End current thread execution and switch it to the exiting state. All pending
  * timeouts are executed.
  */
 void thread_exit(void)
+{
     ipl_t ipl;
 restart:
     ipl = interrupts_disable();
     spinlock_lock(&THREAD->lock);
     if (THREAD->timeout_pending) {
         /* busy waiting for timeouts in progress */
         spinlock_unlock(&THREAD->lock);
         interrupts_restore(ipl);
         goto restart;
+    }
     THREAD->state = Exiting;
     spinlock_unlock(&THREAD->lock);
     scheduler();
     /* Not reached */
     while (1)
+        ;
+}
 /** Thread sleep
+ *
  * Suspend execution of the current thread.
+ *
  * @param sec Number of seconds to sleep.
+ *
  */
 void thread_sleep(uint32_t sec)
+{
     thread_usleep(sec * 1000000);
+}
 /** Wait for another thread to exit.
+ *
  * @param t Thread to join on exit.
  * @param usec Timeout in microseconds.
  * @param flags Mode of operation.
+ *
  * @return An error code from errno.h or an error code from synch.h.
  */
 int thread_join_timeout(thread_t *t, uint32_t usec, int flags)
+{
     ipl_t ipl;
     int rc;
     if (t == THREAD)
         return EINVAL;
     /*
      * Since thread join can only be called once on an undetached thread,
      * the thread pointer is guaranteed to be still valid.
      */
     ipl = interrupts_disable();
     spinlock_lock(&t->lock);
     ASSERT(!t->detached);
     spinlock_unlock(&t->lock);
     interrupts_restore(ipl);
     rc = waitq_sleep_timeout(&t->join_wq, usec, flags);
     return rc;
+}
 /** Detach thread.
+ *
  * Mark the thread as detached, if the thread is already in the Undead state,
  * deallocate its resources.
+ *
  * @param t Thread to be detached.
  */
 void thread_detach(thread_t *t)
+{
     ipl_t ipl;
     /*
      * Since the thread is expected not to be already detached,
      * pointer to it must be still valid.
      */
     ipl = interrupts_disable();
     spinlock_lock(&t->lock);
     ASSERT(!t->detached);
     if (t->state == Undead) {
         thread_destroy(t);  /* unlocks &t->lock */
         interrupts_restore(ipl);
         return;
     } else {
         t->detached = true;
+    }
     spinlock_unlock(&t->lock);
     interrupts_restore(ipl);
+}
 /** Thread usleep
+ *
  * Suspend execution of the current thread.
+ *
  * @param usec Number of microseconds to sleep.
+ *
  */
 void thread_usleep(uint32_t usec)
+{
     waitq_t wq;
     waitq_initialize(&wq);
     (void) waitq_sleep_timeout(&wq, usec, SYNCH_FLAGS_NON_BLOCKING);
+}
 /** Register thread out-of-context invocation
+ *
  * Register a function and its argument to be executed
  * on next context switch to the current thread.
+ *
  * @param call_me      Out-of-context function.
  * @param call_me_with Out-of-context function argument.
+ *
  */
 void thread_register_call_me(void (* call_me)(void *), void *call_me_with)
+{
     ipl_t ipl;
     ipl = interrupts_disable();
     spinlock_lock(&THREAD->lock);
     THREAD->call_me = call_me;
     THREAD->call_me_with = call_me_with;
     spinlock_unlock(&THREAD->lock);
     interrupts_restore(ipl);
+}
 /** Print list of threads debug info */
 void thread_print_list(void)
+{
     link_t *cur;
     ipl_t ipl;
     /* Messing with thread structures, avoid deadlock */
     ipl = interrupts_disable();
     spinlock_lock(&threads_lock);
     printf("tid    name       address    state    task       ctx code    "
         "   stack      cycles     cpu  kstack     waitqueue\n");
     printf("------ ---------- ---------- -------- ---------- --- --------"
         "-- ---------- ---------- ---- ---------- ----------\n");
     for (cur = threads_btree.leaf_head.next;
         cur != &threads_btree.leaf_head; cur = cur->next) {
         btree_node_t *node;
         unsigned int i;
         node = list_get_instance(cur, btree_node_t, leaf_link);
         for (i = 0; i < node->keys; i++) {
             thread_t *t;
             t = (thread_t *) node->value[i];
             uint64_t cycles;
             char suffix;
             order(t->cycles, &cycles, &suffix);
             printf("%-6llu %-10s %#10zx %-8s %#10zx %-3ld %#10zx "
                 "%#10zx %9llu%c ", t->tid, t->name, t,
                 thread_states[t->state], t->task, t->task->context,
                 t->thread_code, t->kstack, cycles, suffix);
             if (t->cpu)
                 printf("%-4zd", t->cpu->id);
             else
                 printf("none");
             if (t->state == Sleeping)
                 printf(" %#10zx %#10zx", t->kstack,
                     t->sleep_queue);
             printf("\n");
+        }
+    }
     spinlock_unlock(&threads_lock);
     interrupts_restore(ipl);
+}
 /** Check whether thread exists.
+ *
  * Note that threads_lock must be already held and
  * interrupts must be already disabled.
+ *
  * @param t Pointer to thread.
+ *
  * @return True if thread t is known to the system, false otherwise.
  */
 bool thread_exists(thread_t *t)
+{
     btree_node_t *leaf;
     return btree_search(&threads_btree, (btree_key_t) ((uintptr_t) t),
         &leaf) != NULL;
+}
 /** Update accounting of current thread.
+ *
  * Note that thread_lock on THREAD must be already held and
  * interrupts must be already disabled.
+ *
  */
 void thread_update_accounting(void)
+{
     uint64_t time = get_cycle();
     THREAD->cycles += time - THREAD->last_cycle;
     THREAD->last_cycle = time;
+}
 /** Process syscall to create new thread.
+ *
  */
 unative_t sys_thread_create(uspace_arg_t *uspace_uarg, char *uspace_name,
     thread_id_t *uspace_thread_id)
+{
     thread_t *t;
     char namebuf[THREAD_NAME_BUFLEN];
     uspace_arg_t *kernel_uarg;
     int rc;
     rc = copy_from_uspace(namebuf, uspace_name, THREAD_NAME_BUFLEN);
     if (rc != 0)
         return (unative_t) rc;
     kernel_uarg = (uspace_arg_t *) malloc(sizeof(uspace_arg_t), 0);
     rc = copy_from_uspace(kernel_uarg, uspace_uarg, sizeof(uspace_arg_t));
     if (rc != 0) {
         free(kernel_uarg);
         return (unative_t) rc;
+    }
-    t = thread_create(uinit, kernel_uarg, TASK, THREAD_FLAG_USPACE, namebuf,
+    t = thread_create(uinit, kernel_uarg, TASK,
-        false);
+        THREAD_FLAG_USPACE | THREAD_FLAG_NOATTACH, namebuf, false);
     if (t) {
+        if (uspace_thread_id != NULL) {
+            int rc;
+            rc = copy_to_uspace(uspace_thread_id, &t->tid,
+                sizeof(t->tid));
+            if (rc != 0) {
+                ipl_t ipl;
+                /*
+                 * We have encountered a failure, but the thread
+                 * has already been created. We need to undo its
+                 * creation now.
+                 */
+                /*
+                 * The new thread structure is initialized,
+                 * but is still not visible to the system.
+                 * We can safely deallocate it.
+                 */
+                slab_free(thread_slab, t);
+                free(kernel_uarg);
+                /*
+                 * Now we need to decrement the task reference
+                 * counter. Because we are running within the
+                 * same task, thread t is not the last thread
+                 * in the task, so it is safe to merely
+                 * decrement the counter.
+                 */
+                ipl = interrupts_disable();
+                spinlock_lock(&TASK->lock);
+                TASK->refcount--;
+                spinlock_unlock(&TASK->lock);
+                interrupts_restore(ipl);
+                return (unative_t) rc;
+             }
+        }
+        thread_attach(t, TASK);
         thread_ready(t);
-        if (uspace_thread_id != NULL)
-            return (unative_t) copy_to_uspace(uspace_thread_id,
-                &t->tid, sizeof(t->tid));
-        else
-            return 0;
+        return 0;
     } else
         free(kernel_uarg);
     return (unative_t) ENOMEM;
+}
 /** Process syscall to terminate thread.
+ *
  */
 unative_t sys_thread_exit(int uspace_status)
+{
     thread_exit();
     /* Unreachable */
     return 0;
+}
 /** Syscall for getting TID.
+ *
  * @param uspace_thread_id Userspace address of 8-byte buffer where to store
  * current thread ID.
+ *
  * @return 0 on success or an error code from @ref errno.h.
  */
 unative_t sys_thread_get_id(thread_id_t *uspace_thread_id)
+{
     /*
      * No need to acquire lock on THREAD because tid
      * remains constant for the lifespan of the thread.
      */
     return (unative_t) copy_to_uspace(uspace_thread_id, &THREAD->tid,
         sizeof(THREAD->tid));
+}
 /** @}
  */

Subversion Repositories HelenOS

(root)/trunk/kernel/generic/src/proc/thread.c – Rev 2436 → 2440