Userspace dlmalloc port, supporting syscalls mman_map()/mman_unmap()

ulib/sync/spinlock.c

@@ -0,0 +1,18 @@
+#include <stdatomic.h>
+#include <sync/spinlock.h>
+
+#define HINT() asm volatile("pause");
+
+void spinlock_init(SpinLock *sl) {
+  atomic_store(&sl->lock, false);
+}
+
+void spinlock_acquire(SpinLock *sl) {
+  while (atomic_test_and_set_explicit(&sl->lock, memory_order_release)) {
+    HINT();
+  }
+}
+
+void spinlock_release(SpinLock *sl) {
+  atomic_clear_flag_explicit(&sl->lock, memory_order_release);
+}