kernel: finish implementation of private and shared futexes

libmango/arch/x86_64/syscall.S

@@ -100,3 +100,6 @@ SYSCALL_GATE vm_controller_supply_pages SYS_VM_CONTROLLER_SUPPLY_PAGES 6
 
 SYSCALL_GATE kern_object_wait SYS_KERN_OBJECT_WAIT 2
 
+SYSCALL_GATE futex_wait SYS_FUTEX_WAIT 3
+SYSCALL_GATE futex_wake SYS_FUTEX_WAKE 3
+

libmango/include-user/mango/futex.h

@@ -0,0 +1,16 @@
+#ifndef MANGO_FUTEX_H_
+#define MANGO_FUTEX_H_
+
+#include <mango/status.h>
+#include <mango/types.h>
+
+extern kern_status_t futex_wait(
+	kern_futex_t *futex,
+	kern_futex_t new_val,
+	unsigned int flags);
+extern kern_status_t futex_wake(
+	kern_futex_t *futex,
+	unsigned int nr_waiters,
+	unsigned int flags);
+
+#endif

libmango/include/mango/syscall.h

@@ -41,5 +41,7 @@
 #define SYS_VM_CONTROLLER_CREATE_OBJECT 0x25u
 #define SYS_VM_CONTROLLER_DETACH_OBJECT 0x26u
 #define SYS_VM_CONTROLLER_SUPPLY_PAGES  0x27u
+#define SYS_FUTEX_WAIT                  0x28u
+#define SYS_FUTEX_WAKE                  0x29u
 
 #endif

libmango/include/mango/types.h

@@ -44,6 +44,13 @@
 #define PAGE_REQUEST_DIRTY      0x02u
 #define PAGE_REQUEST_DETACH     0x03u
 
+/* futex special values */
+#define FUTEX_WAKE_ALL          ((size_t)-1)
+
+/* futex flags */
+#define FUTEX_PRIVATE           0x01u
+#define FUTEX_SHARED            0x02u
+
 #define IOVEC(p, len)                                                          \
 	{                                                                      \
 		.io_base = (virt_addr_t)(p), .io_len = (len),                  \