1 files changed, 126 insertions, 0 deletions
diff --git a/os/port/taslock.c b/os/port/taslock.c
new file mode 100644
index 00000000..7914b80a
--- /dev/null
+++ b/os/port/taslock.c
@@ -0,0 +1,126 @@
+#include "u.h"
+#include "../port/lib.h"
+#include "mem.h"
+#include "dat.h"
+#include "fns.h"
+#include "../port/error.h"
+
+static void
+lockloop(Lock *l, ulong pc)
+{
+	setpanic();
+	print("lock loop 0x%lux key 0x%lux pc 0x%lux held by pc 0x%lux\n", l, l->key, pc, l->pc);
+	panic("lockloop");
+}
+
+void
+lock(Lock *l)
+{
+	int i;
+	ulong pc;
+
+	pc = getcallerpc(&l);
+	if(up == 0) {
+		if (_tas(&l->key) != 0) {
+			for(i=0; ; i++) {
+				if(_tas(&l->key) == 0)
+					break;
+				if (i >= 1000000) {
+					lockloop(l, pc);
+					break;
+				}
+			}
+		}
+		l->pc = pc;
+		return;
+	}
+
+	for(i=0; ; i++) {
+		if(_tas(&l->key) == 0)
+			break;
+		if (i >= 1000) {
+			lockloop(l, pc);
+			break;
+		}
+		if(conf.nmach == 1 && up->state == Running && islo()) {
+			up->pc = pc;
+			sched();
+		}
+	}
+	l->pri = up->pri;
+	up->pri = PriLock;
+	l->pc = pc;
+}
+
+void
+ilock(Lock *l)
+{
+	ulong x, pc;
+	int i;
+
+	pc = getcallerpc(&l);
+	x = splhi();
+	for(;;) {
+		if(_tas(&l->key) == 0) {
+			l->sr = x;
+			l->pc = pc;
+			return;
+		}
+		if(conf.nmach < 2)
+			panic("ilock: no way out: pc 0x%lux: lock 0x%lux held by pc 0x%lux", pc, l, l->pc);
+		for(i=0; ; i++) {
+			if(l->key == 0)
+				break;
+			clockcheck();
+			if (i > 100000) {
+				lockloop(l, pc);
+				break;
+			}
+		}
+	}
+}
+
+int
+canlock(Lock *l)
+{
+	if(_tas(&l->key))
+		return 0;
+	if(up){
+		l->pri = up->pri;
+		up->pri = PriLock;
+	}
+	l->pc = getcallerpc(&l);
+	return 1;
+}
+
+void
+unlock(Lock *l)
+{
+	int p;
+
+	if(l->key == 0)
+		print("unlock: not locked: pc %lux\n", getcallerpc(&l));
+	p = l->pri;
+	l->pc = 0;
+	l->key = 0;
+	coherence();
+	if(up){
+		up->pri = p;
+		if(up->state == Running && anyhigher())
+			sched();
+	}
+}
+
+void
+iunlock(Lock *l)
+{
+	ulong sr;
+
+	if(l->key == 0)
+		print("iunlock: not locked: pc %lux\n", getcallerpc(&l));
+	sr = l->sr;
+	l->pc = 0;
+	l->key = 0;
+	coherence();
+	splxpc(sr);
+}