Add Windows and POSIX versions, as usual.
Signed-off-by: Paolo Bonzini <[email protected]>
---
compiler.h | 2 ++
qemu-thread-posix.c | 5 +++++
qemu-thread-posix.h | 5 +++++
qemu-thread-win32.c | 19 +++++++++++++++++++
qemu-thread-win32.h | 5 +++++
qemu-thread.h | 3 +++
6 files changed, 39 insertions(+), 0 deletions(-)
diff --git a/compiler.h b/compiler.h
index 9af5dc6..c87dd96 100644
--- a/compiler.h
+++ b/compiler.h
@@ -31,4 +31,6 @@
#define GCC_FMT_ATTR(n, m)
#endif
+#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
+
#endif /* COMPILER_H */
diff --git a/qemu-thread-posix.c b/qemu-thread-posix.c
index 50e7421..894134c 100644
--- a/qemu-thread-posix.c
+++ b/qemu-thread-posix.c
@@ -239,6 +239,11 @@ void qemu_event_wait(QemuEvent *ev)
}
}
+void qemu_once(QemuOnce *o, void (*func)(void))
+{
+ pthread_once(&o->once, func);
+}
+
void qemu_thread_create(QemuThread *thread,
void *(*start_routine)(void*),
void *arg)
diff --git a/qemu-thread-posix.h b/qemu-thread-posix.h
index 2f5b63d..d781ca6 100644
--- a/qemu-thread-posix.h
+++ b/qemu-thread-posix.h
@@ -18,6 +18,11 @@ struct QemuEvent {
unsigned value;
};
+#define QEMU_ONCE_INIT { .once = PTHREAD_ONCE_INIT }
+struct QemuOnce {
+ pthread_once_t once;
+};
+
struct QemuThread {
pthread_t thread;
};
diff --git a/qemu-thread-win32.c b/qemu-thread-win32.c
index 9bdbb48..7b1c407 100644
--- a/qemu-thread-win32.c
+++ b/qemu-thread-win32.c
@@ -12,6 +12,7 @@
*/
#include "qemu-common.h"
#include "qemu-thread.h"
+#include "qemu-barrier.h"
#include <process.h>
#include <assert.h>
#include <limits.h>
@@ -218,6 +219,24 @@ void qemu_event_wait(QemuEvent *ev)
WaitForSingleObject(ev->event, INFINITE);
}
+void qemu_once(QemuOnce *o, void (*func)(void))
+{
+ int old;
+ if (once->state != 2) {
+ old = __sync_val_compare_and_swap (&once->state, 0, 1);
+ if (old == 0) {
+ func();
+ once->state = 2;
+ smp_mb();
+ return;
+ }
+ /* Busy wait until the first thread gives us a green flag. */
+ while (ACCESS_ONCE(once->state) == 1) {
+ Sleep(0);
+ }
+ }
+}
+
struct QemuThreadData {
QemuThread *thread;
void *(*start_routine)(void *);
diff --git a/qemu-thread-win32.h b/qemu-thread-win32.h
index ddd6d0f..fbee4d9 100644
--- a/qemu-thread-win32.h
+++ b/qemu-thread-win32.h
@@ -17,6 +17,11 @@ struct QemuEvent {
HANDLE event;
};
+#define QEMU_ONCE_INIT = { .state = 0 }
+struct QemuOnce {
+ int state;
+}
+
struct QemuThread {
HANDLE thread;
void *ret;
diff --git a/qemu-thread.h b/qemu-thread.h
index 8353e3d..ae75638 100644
--- a/qemu-thread.h
+++ b/qemu-thread.h
@@ -7,6 +7,7 @@
typedef struct QemuMutex QemuMutex;
typedef struct QemuCond QemuCond;
typedef struct QemuEvent QemuEvent;
+typedef struct QemuOnce QemuOnce;
typedef struct QemuThread QemuThread;
#ifdef _WIN32
@@ -39,6 +40,8 @@ void qemu_event_reset(QemuEvent *ev);
void qemu_event_wait(QemuEvent *ev);
void qemu_event_destroy(QemuEvent *ev);
+void qemu_once(QemuOnce *o, void (*func)(void));
+
void qemu_thread_create(QemuThread *thread,
void *(*start_routine)(void*),
void *arg);
--
1.7.6
