target-i386: fix "info lapic" segfault on isapc

[mirror_qemu.git] / util / qemu-thread-posix.c

diff --git a/util/qemu-thread-posix.c b/util/qemu-thread-posix.c
index 50a29d8f7aad7fe5882ba33d18dce4b7bf2ccb97..73e3a0edf5613ae1ab4fcd1b684395b9476d0072 100644 (file)
--- a/util/qemu-thread-posix.c
+++ b/util/qemu-thread-posix.c
@@ -10,20 +10,7 @@
  * See the COPYING file in the top-level directory.
  *
  */
-#include <stdlib.h>
-#include <stdio.h>
-#include <errno.h>
-#include <time.h>
-#include <signal.h>
-#include <stdint.h>
-#include <string.h>
-#include <limits.h>
-#include <unistd.h>
-#include <sys/time.h>
-#ifdef __linux__
-#include <sys/syscall.h>
-#include <linux/futex.h>
-#endif
+#include "qemu/osdep.h"
 #include "qemu/thread.h"
 #include "qemu/atomic.h"
 #include "qemu/notify.h"
@@ -51,12 +38,8 @@ static void error_exit(int err, const char *msg)
 void qemu_mutex_init(QemuMutex *mutex)
 {
     int err;
-    pthread_mutexattr_t mutexattr;
 
-    pthread_mutexattr_init(&mutexattr);
-    pthread_mutexattr_settype(&mutexattr, PTHREAD_MUTEX_ERRORCHECK);
-    err = pthread_mutex_init(&mutex->lock, &mutexattr);
-    pthread_mutexattr_destroy(&mutexattr);
+    err = pthread_mutex_init(&mutex->lock, NULL);
     if (err)
         error_exit(err, __func__);
 }
@@ -93,6 +76,20 @@ void qemu_mutex_unlock(QemuMutex *mutex)
         error_exit(err, __func__);
 }
 
+void qemu_rec_mutex_init(QemuRecMutex *mutex)
+{
+    int err;
+    pthread_mutexattr_t attr;
+
+    pthread_mutexattr_init(&attr);
+    pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
+    err = pthread_mutex_init(&mutex->lock, &attr);
+    pthread_mutexattr_destroy(&attr);
+    if (err) {
+        error_exit(err, __func__);
+    }
+}
+
 void qemu_cond_init(QemuCond *cond)
 {
     int err;
@@ -293,19 +290,9 @@ void qemu_sem_wait(QemuSemaphore *sem)
 }
 
 #ifdef __linux__
-#define futex(...)              syscall(__NR_futex, __VA_ARGS__)
-
-static inline void futex_wake(QemuEvent *ev, int n)
-{
-    futex(ev, FUTEX_WAKE, n, NULL, NULL, 0);
-}
-
-static inline void futex_wait(QemuEvent *ev, unsigned val)
-{
-    futex(ev, FUTEX_WAIT, (int) val, NULL, NULL, 0);
-}
+#include "qemu/futex.h"
 #else
-static inline void futex_wake(QemuEvent *ev, int n)
+static inline void qemu_futex_wake(QemuEvent *ev, int n)
 {
     pthread_mutex_lock(&ev->lock);
     if (n == 1) {
@@ -316,7 +303,7 @@ static inline void futex_wake(QemuEvent *ev, int n)
     pthread_mutex_unlock(&ev->lock);
 }
 
-static inline void futex_wait(QemuEvent *ev, unsigned val)
+static inline void qemu_futex_wait(QemuEvent *ev, unsigned val)
 {
     pthread_mutex_lock(&ev->lock);
     if (ev->value == val) {
@@ -328,7 +315,7 @@ static inline void futex_wait(QemuEvent *ev, unsigned val)
 
 /* Valid transitions:
  * - free->set, when setting the event
- * - busy->set, when setting the event, followed by futex_wake
+ * - busy->set, when setting the event, followed by qemu_futex_wake
  * - set->free, when resetting the event
  * - free->busy, when waiting
  *
@@ -364,17 +351,25 @@ void qemu_event_destroy(QemuEvent *ev)
 
 void qemu_event_set(QemuEvent *ev)
 {
-    if (atomic_mb_read(&ev->value) != EV_SET) {
+    /* qemu_event_set has release semantics, but because it *loads*
+     * ev->value we need a full memory barrier here.
+     */
+    smp_mb();
+    if (atomic_read(&ev->value) != EV_SET) {
         if (atomic_xchg(&ev->value, EV_SET) == EV_BUSY) {
             /* There were waiters, wake them up.  */
-            futex_wake(ev, INT_MAX);
+            qemu_futex_wake(ev, INT_MAX);
         }
     }
 }
 
 void qemu_event_reset(QemuEvent *ev)
 {
-    if (atomic_mb_read(&ev->value) == EV_SET) {
+    unsigned value;
+
+    value = atomic_read(&ev->value);
+    smp_mb_acquire();
+    if (value == EV_SET) {
         /*
          * If there was a concurrent reset (or even reset+wait),
          * do nothing.  Otherwise change EV_SET->EV_FREE.
@@ -387,20 +382,21 @@ void qemu_event_wait(QemuEvent *ev)
 {
     unsigned value;
 
-    value = atomic_mb_read(&ev->value);
+    value = atomic_read(&ev->value);
+    smp_mb_acquire();
     if (value != EV_SET) {
         if (value == EV_FREE) {
             /*
              * Leave the event reset and tell qemu_event_set that there
              * are waiters.  No need to retry, because there cannot be
-             * a concurent busy->free transition.  After the CAS, the
+             * a concurrent busy->free transition.  After the CAS, the
              * event will be either set or busy.
              */
             if (atomic_cmpxchg(&ev->value, EV_FREE, EV_BUSY) == EV_SET) {
                 return;
             }
         }
-        futex_wait(ev, EV_BUSY);
+        qemu_futex_wait(ev, EV_BUSY);
     }
 }
 
@@ -462,12 +458,6 @@ void qemu_thread_create(QemuThread *thread, const char *name,
     if (err) {
         error_exit(err, __func__);
     }
-    if (mode == QEMU_THREAD_DETACHED) {
-        err = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
-        if (err) {
-            error_exit(err, __func__);
-        }
-    }
 
     /* Leave signal handling to the iothread.  */
     sigfillset(&set);
@@ -480,6 +470,12 @@ void qemu_thread_create(QemuThread *thread, const char *name,
         qemu_thread_set_name(thread, name);
     }
 
+    if (mode == QEMU_THREAD_DETACHED) {
+        err = pthread_detach(thread->thread);
+        if (err) {
+            error_exit(err, __func__);
+        }
+    }
     pthread_sigmask(SIG_SETMASK, &oldset, NULL);
 
     pthread_attr_destroy(&attr);