kernel: add a syscall to query generic information about an object

libmango/include/mango/syscall.h

@@ -49,5 +49,6 @@
 #define SYS_VM_CONTROLLER_SUPPLY_PAGES  46
 #define SYS_FUTEX_WAIT                  47
 #define SYS_FUTEX_WAKE                  48
+#define SYS_KERN_OBJECT_QUERY           49
 
 #endif

libmango/include/mango/types.h

@@ -109,6 +109,10 @@ typedef unsigned short equeue_packet_type_t;
 
 typedef unsigned int umode_t;
 
+typedef struct {
+	koid_t obj_id;
+} kern_object_info_t;
+
 typedef struct {
 	virt_addr_t io_base;
 	size_t io_len;