Move syslet/indirect bits into the OS specific directory

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/os/syslet.h b/os/syslet.h
new file mode 100644
index 0000000..095cc13
--- /dev/null
+++ b/os/syslet.h
@@ -0,0 +1,50 @@
+#ifndef _SYSLET_H_
+#define _SYSLET_H_
+
+#include "kcompat.h"
+
+struct syslet_frame {
+	u64 ip;
+	u64 sp;
+};
+
+struct syslet_args {
+	u64 ring_ptr;
+	u64 caller_data;
+	struct syslet_frame frame;
+};
+
+struct syslet_completion {
+	u64 status;
+	u64 caller_data;
+};
+
+struct syslet_ring {
+	u32 kernel_head;
+	u32 user_tail;
+	u32 elements;
+	u32 wait_group;
+	struct syslet_completion comp[0];
+};
+
+#ifdef __x86_64__
+#define __NR_syslet_ring_wait	287
+#elif defined __i386__
+#define __NR_syslet_ring_wait	326
+#endif
+
+#define ESYSLETPENDING   132
+
+typedef void (*syslet_return_func_t)(void);
+
+static inline void fill_syslet_args(struct syslet_args *args,
+		      struct syslet_ring *ring, uint64_t caller_data,
+		      syslet_return_func_t func, void *stack)
+{
+	args->ring_ptr = (u64)(unsigned long)ring;
+	args->caller_data = caller_data;
+	args->frame.ip = (u64)(unsigned long)func;
+	args->frame.sp = (u64)(unsigned long)stack;
+}
+
+#endif