1 files changed, 23 insertions, 0 deletions
diff --git a/libc-top-half/musl/src/thread/vmlock.c b/libc-top-half/musl/src/thread/vmlock.c
new file mode 100644
index 0000000..fa0a8e3
--- /dev/null
+++ b/libc-top-half/musl/src/thread/vmlock.c
@@ -0,0 +1,23 @@
+#include "pthread_impl.h"
+#include "fork_impl.h"
+
+static volatile int vmlock[2];
+volatile int *const __vmlock_lockptr = vmlock;
+
+void __vm_wait()
+{
+	int tmp;
+	while ((tmp=vmlock[0]))
+		__wait(vmlock, vmlock+1, tmp, 1);
+}
+
+void __vm_lock()
+{
+	a_inc(vmlock);
+}
+
+void __vm_unlock()
+{
+	if (a_fetch_add(vmlock, -1)==1 && vmlock[1])
+		__wake(vmlock, -1, 1);
+}