02245e6120
to be instances where the kernel doesn't properly save and/or
restore it.
Use noupcall and nocompleted flags in the KSE mailbox. These
require kernel changes to work which will be committed sometime
later. Things still work without the changes.
Remove the general kse entry function and use two different
functions -- one for scope system threads and one for scope
process threads. The scope system function is not yet enabled
and we use the same function for all threads at the moment.
Keep a copy of the KSE stack for the case that a KSE runs
a scope system thread and uses the same stack as the thread
(no upcalls are generated, so a separate stack isn't needed).
This isn't enabled yet.
Use a separate field for the KSE waiting flag. It isn't
correct to use the mailbox flags field.
The following fixes were provided by David Xu:
o Initialize condition variable locks with thread versions
of the low-level locking functions instead of the kse versions.
o Enable threading before creating the first thread instead
of after.
o Don't enter critical regions when trying to malloc/free
or call functions that malloc/free.
o Take the scheduling lock when inheriting thread attributes.
o Check the attribute's stack pointer instead of the
attributes stack size for null when allocating a
thread's stack.
o Add a kseg reinit function so we don't have to destroy and
then recreate the same lock.
o Check the return value of kse_create() and return an
appropriate error if it fails.
o Don't forget to destroy a thread's locks when freeing it.
o Examine the correct flags word for checking to see if
a thread is in a synchronization queue.
Things should now work on an SMP kernel.
337 lines
10 KiB
C
337 lines
10 KiB
C
/*
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* Copyright (c) 2003 Daniel M. Eischen <deischen@gdeb.com>
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* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by John Birrell.
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* 4. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <stddef.h>
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#include <sys/time.h>
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#include <machine/reg.h>
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#include <pthread.h>
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#include "thr_private.h"
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#include "libc_private.h"
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static u_int64_t next_uniqueid = 1;
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#define OFF(f) offsetof(struct pthread, f)
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int _thread_next_offset = OFF(tle.tqe_next);
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int _thread_uniqueid_offset = OFF(uniqueid);
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int _thread_state_offset = OFF(state);
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int _thread_name_offset = OFF(name);
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int _thread_ctx_offset = OFF(tmbx.tm_context);
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#undef OFF
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int _thread_PS_RUNNING_value = PS_RUNNING;
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int _thread_PS_DEAD_value = PS_DEAD;
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static int create_stack(struct pthread_attr *pattr);
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static void thread_start(struct pthread *curthread,
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void *(*start_routine) (void *), void *arg);
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__weak_reference(_pthread_create, pthread_create);
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/*
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* Some notes on new thread creation and first time initializion
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* to enable multi-threading.
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*
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* There are basically two things that need to be done.
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*
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* 1) The internal library variables must be initialized.
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* 2) Upcalls need to be enabled to allow multiple threads
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* to be run.
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*
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* The first may be done as a result of other pthread functions
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* being called. When _thr_initial is null, _libpthread_init is
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* called to initialize the internal variables; this also creates
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* or sets the initial thread. It'd be nice to automatically
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* have _libpthread_init called on program execution so we don't
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* have to have checks throughout the library.
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*
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* The second part is only triggered by the creation of the first
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* thread (other than the initial/main thread). If the thread
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* being created is a scope system thread, then a new KSE/KSEG
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* pair needs to be allocated. Also, if upcalls haven't been
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* enabled on the initial thread's KSE, they must be now that
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* there is more than one thread; this could be delayed until
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* the initial KSEG has more than one thread.
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*/
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int
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_pthread_create(pthread_t * thread, const pthread_attr_t * attr,
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void *(*start_routine) (void *), void *arg)
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{
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struct kse *curkse;
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struct pthread *curthread, *new_thread;
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struct kse *kse = NULL;
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struct kse_group *kseg = NULL;
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kse_critical_t crit;
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int i;
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int ret = 0;
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if (_thr_initial == NULL)
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_libpthread_init(NULL);
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/*
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* Turn on threaded mode, if failed, it is unnecessary to
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* do further work.
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*/
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if (_kse_isthreaded() == 0 && _kse_setthreaded(1)) {
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return (EAGAIN);
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}
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curthread = _get_curthread();
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/*
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* Allocate memory for the thread structure.
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* Some functions use malloc, so don't put it
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* in a critical region.
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*/
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if ((new_thread = _thr_alloc(curthread)) == NULL) {
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/* Insufficient memory to create a thread: */
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ret = EAGAIN;
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} else {
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/* Initialize the thread structure: */
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memset(new_thread, 0, sizeof(struct pthread));
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/* Check if default thread attributes are required: */
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if (attr == NULL || *attr == NULL)
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/* Use the default thread attributes: */
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new_thread->attr = _pthread_attr_default;
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else
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new_thread->attr = *(*attr);
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if (create_stack(&new_thread->attr) != 0) {
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/* Insufficient memory to create a stack: */
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ret = EAGAIN;
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_thr_free(curthread, new_thread);
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}
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else if (((new_thread->attr.flags & PTHREAD_SCOPE_SYSTEM) != 0) &&
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(((kse = _kse_alloc(curthread)) == NULL)
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|| ((kseg = _kseg_alloc(curthread)) == NULL))) {
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/* Insufficient memory to create a new KSE/KSEG: */
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ret = EAGAIN;
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if (kse != NULL)
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_kse_free(curthread, kse);
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if ((new_thread->attr.flags & THR_STACK_USER) == 0) {
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crit = _kse_critical_enter();
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curkse = _get_curkse();
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KSE_LOCK_ACQUIRE(curkse, &_thread_list_lock);
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/* Stack routines don't use malloc/free. */
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_thr_stack_free(&new_thread->attr);
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KSE_LOCK_RELEASE(curkse, &_thread_list_lock);
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_kse_critical_leave(crit);
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}
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_thr_free(curthread, new_thread);
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}
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else {
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if (kseg != NULL) {
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/* Add the KSE to the KSEG's list of KSEs. */
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TAILQ_INSERT_HEAD(&kseg->kg_kseq, kse, k_qe);
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kse->k_kseg = kseg;
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kse->k_schedq = &kseg->kg_schedq;
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}
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/*
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* Write a magic value to the thread structure
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* to help identify valid ones:
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*/
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new_thread->magic = THR_MAGIC;
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new_thread->slice_usec = -1;
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new_thread->start_routine = start_routine;
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new_thread->arg = arg;
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new_thread->cancelflags = PTHREAD_CANCEL_ENABLE |
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PTHREAD_CANCEL_DEFERRED;
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/* Initialize the thread for signals: */
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new_thread->sigmask = curthread->sigmask;
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/* No thread is wanting to join to this one: */
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new_thread->joiner = NULL;
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/* Initialize the signal frame: */
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new_thread->curframe = NULL;
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/*
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* Initialize the machine context.
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* Enter a critical region to get consistent context.
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*/
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crit = _kse_critical_enter();
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THR_GETCONTEXT(&new_thread->tmbx.tm_context);
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_kse_critical_leave(crit);
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new_thread->tmbx.tm_udata = new_thread;
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new_thread->tmbx.tm_context.uc_sigmask =
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new_thread->sigmask;
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new_thread->tmbx.tm_context.uc_stack.ss_size =
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new_thread->attr.stacksize_attr;
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new_thread->tmbx.tm_context.uc_stack.ss_sp =
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new_thread->attr.stackaddr_attr;
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makecontext(&new_thread->tmbx.tm_context,
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(void (*)(void))thread_start, 4, new_thread,
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start_routine, arg);
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/*
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* Check if this thread is to inherit the scheduling
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* attributes from its parent:
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*/
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if ((new_thread->attr.flags & PTHREAD_INHERIT_SCHED) != 0) {
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/*
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* Copy the scheduling attributes.
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* Lock the scheduling lock to get consistent
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* scheduling parameters.
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*/
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THR_SCHED_LOCK(curthread, curthread);
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new_thread->base_priority =
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curthread->base_priority &
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~THR_SIGNAL_PRIORITY;
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new_thread->attr.prio =
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curthread->base_priority &
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~THR_SIGNAL_PRIORITY;
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new_thread->attr.sched_policy =
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curthread->attr.sched_policy;
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THR_SCHED_UNLOCK(curthread, curthread);
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} else {
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/*
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* Use just the thread priority, leaving the
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* other scheduling attributes as their
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* default values:
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*/
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new_thread->base_priority =
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new_thread->attr.prio;
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}
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new_thread->active_priority = new_thread->base_priority;
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new_thread->inherited_priority = 0;
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/* Initialize the mutex queue: */
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TAILQ_INIT(&new_thread->mutexq);
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/*
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* Initialize thread locking.
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* Lock initializing needs malloc, so don't
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* enter critical region before doing this!
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*/
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if (_lock_init(&new_thread->lock, LCK_ADAPTIVE,
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_thr_lock_wait, _thr_lock_wakeup) != 0)
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PANIC("Cannot initialize thread lock");
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for (i = 0; i < MAX_THR_LOCKLEVEL; i++) {
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_lockuser_init(&new_thread->lockusers[i],
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(void *)new_thread);
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_LCK_SET_PRIVATE2(&new_thread->lockusers[i],
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(void *)new_thread);
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}
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/* Initialise hooks in the thread structure: */
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new_thread->specific = NULL;
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new_thread->cleanup = NULL;
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new_thread->flags = 0;
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new_thread->continuation = NULL;
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if (new_thread->attr.suspend == THR_CREATE_SUSPENDED)
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new_thread->state = PS_SUSPENDED;
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else
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new_thread->state = PS_RUNNING;
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/*
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* System scope threads have their own kse and
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* kseg. Process scope threads are all hung
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* off the main process kseg.
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*/
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if ((new_thread->attr.flags & PTHREAD_SCOPE_SYSTEM) == 0) {
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new_thread->kseg = _kse_initial->k_kseg;
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new_thread->kse = _kse_initial;
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}
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else {
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kse->k_curthread = NULL;
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#ifdef NOT_YET
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kse->k_kseg->kg_flags |= KGF_SINGLE_THREAD;
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#endif
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new_thread->kse = kse;
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new_thread->kseg = kse->k_kseg;
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kse->k_mbx.km_udata = kse;
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kse->k_mbx.km_curthread = NULL;
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}
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crit = _kse_critical_enter();
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KSE_LOCK_ACQUIRE(curthread->kse, &_thread_list_lock);
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/*
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* Initialise the unique id which GDB uses to
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* track threads.
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*/
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new_thread->uniqueid = next_uniqueid++;
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/* Add the thread to the linked list of all threads: */
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THR_LIST_ADD(new_thread);
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KSE_LOCK_RELEASE(curthread->kse, &_thread_list_lock);
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/*
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* Schedule the new thread starting a new KSEG/KSE
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* pair if necessary.
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*/
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_thr_schedule_add(curthread, new_thread);
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_kse_critical_leave(crit);
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/* Return a pointer to the thread structure: */
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(*thread) = new_thread;
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}
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}
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/* Return the status: */
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return (ret);
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}
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static int
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create_stack(struct pthread_attr *pattr)
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{
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int ret;
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/* Check if a stack was specified in the thread attributes: */
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if ((pattr->stackaddr_attr) != NULL) {
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pattr->guardsize_attr = 0;
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pattr->flags = THR_STACK_USER;
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ret = 0;
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}
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else
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ret = _thr_stack_alloc(pattr);
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return (ret);
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}
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static void
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thread_start(struct pthread *curthread, void *(*start_routine) (void *),
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void *arg)
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{
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/* Run the current thread's start routine with argument: */
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pthread_exit(start_routine(arg));
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/* This point should never be reached. */
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PANIC("Thread has resumed after exit");
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}
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