[kernel] Add event syscalls

The event object was missing any syscalls. Furthermore, kobject had an
old object_signal implementation (the syscall itself no longer exists),
which was removed. User code should only be able to set signals on
events.

src/kernel/kernel.module

@@ -53,6 +53,7 @@ kernel = module("kernel",
         "syscalls.inc.cog",
         "syscalls/channel.cpp",
         "syscalls/endpoint.cpp",
+        "syscalls/event.cpp",
         "syscalls/handle.cpp",
         "syscalls/object.cpp",
         "syscalls/process.cpp",

src/kernel/syscalls/event.cpp

@@ -0,0 +1,36 @@
+#include <j6/errors.h>
+#include <j6/signals.h>
+
+#include "objects/event.h"
+#include "syscalls/helpers.h"
+
+using namespace obj;
+
+namespace syscalls {
+
+j6_status_t
+event_create(j6_handle_t *self)
+{
+    construct_handle<event>(self);
+    return j6_status_ok;
+}
+
+j6_status_t
+event_signal(event *self, j6_signal_t signals)
+{
+    if (signals & j6_signal_global_mask)
+        return j6_err_invalid_arg;
+
+    self->assert_signal(signals);
+    return j6_status_ok;
+}
+
+j6_status_t
+event_clear(event *self, j6_signal_t mask)
+{
+    self->deassert_signal(~mask);
+    return j6_status_ok;
+}
+
+
+} // namespace syscalls

src/kernel/syscalls/object.cpp

@@ -89,16 +89,6 @@ object_wait_many(j6_handle_t * handles, size_t handles_count, uint64_t mask, j6_
     return j6_status_ok;
 }
 
-j6_status_t
-object_signal(kobject *self, j6_signal_t signals)
-{
-    if ((signals & j6_signal_user_mask) != signals)
-        return j6_err_invalid_arg;
-
-    self->assert_signal(signals);
-    return j6_status_ok;
-}
-
 j6_status_t
 object_close(kobject *self)
 {

src/libraries/j6/include/j6/signals.h

@@ -2,73 +2,21 @@
 /// \file signals.h
 /// Collection of constants for the j6_signal_t type
 
-// Signals 0-15 are common to all types
-#define j6_signal_no_handles        (1ull << 0)
-#define j6_signal_closed            (1ull << 1)
+// Signals 56-63 are common to all types
+#define j6_signal_no_handles        (1ull << 56)
+#define j6_signal_closed            (1ull << 57)
+#define j6_signal_global_mask       0xff00000000000000
 
-// Signals 16-47 are defined per-object-type
-
-// Event signals
-#define j7_signal_event00           (1ull << 16)
-#define j7_signal_event01           (1ull << 17)
-#define j7_signal_event02           (1ull << 18)
-#define j7_signal_event03           (1ull << 19)
-#define j7_signal_event04           (1ull << 20)
-#define j7_signal_event05           (1ull << 21)
-#define j7_signal_event06           (1ull << 22)
-#define j7_signal_event07           (1ull << 23)
-#define j7_signal_event08           (1ull << 24)
-#define j7_signal_event09           (1ull << 25)
-#define j7_signal_event10           (1ull << 26)
-#define j7_signal_event11           (1ull << 27)
-#define j7_signal_event12           (1ull << 28)
-#define j7_signal_event13           (1ull << 29)
-#define j7_signal_event14           (1ull << 30)
-#define j7_signal_event15           (1ull << 31)
-#define j7_signal_event16           (1ull << 32)
-#define j7_signal_event17           (1ull << 33)
-#define j7_signal_event18           (1ull << 34)
-#define j7_signal_event19           (1ull << 35)
-#define j7_signal_event20           (1ull << 36)
-#define j7_signal_event21           (1ull << 37)
-#define j7_signal_event22           (1ull << 38)
-#define j7_signal_event23           (1ull << 39)
-#define j7_signal_event24           (1ull << 40)
-#define j7_signal_event25           (1ull << 41)
-#define j7_signal_event26           (1ull << 42)
-#define j7_signal_event27           (1ull << 43)
-#define j7_signal_event28           (1ull << 44)
-#define j7_signal_event29           (1ull << 45)
-#define j7_signal_event30           (1ull << 46)
-#define j7_signal_event31           (1ull << 47)
+// Signals 0-55 are defined per object type
 
 // System signals
-#define j6_signal_system_has_log    (1ull << 16)
+#define j6_signal_system_has_log    (1ull <<  0)
 
 // Channel signals
-#define j6_signal_channel_can_send  (1ull << 16)
-#define j6_signal_channel_can_recv  (1ull << 17)
+#define j6_signal_channel_can_send  (1ull <<  0)
+#define j6_signal_channel_can_recv  (1ull <<  1)
 
 // Endpoint signals
-#define j6_signal_endpoint_can_send (1ull << 16)
-#define j6_signal_endpoint_can_recv (1ull << 17)
+#define j6_signal_endpoint_can_send (1ull <<  0)
+#define j6_signal_endpoint_can_recv (1ull <<  1)
 
-// Signals 48-63 are user-defined signals
-#define j6_signal_user0             (1ull << 48)
-#define j6_signal_user1             (1ull << 49)
-#define j6_signal_user2             (1ull << 50)
-#define j6_signal_user3             (1ull << 51)
-#define j6_signal_user4             (1ull << 52)
-#define j6_signal_user5             (1ull << 53)
-#define j6_signal_user6             (1ull << 54)
-#define j6_signal_user7             (1ull << 55)
-#define j6_signal_user8             (1ull << 56)
-#define j6_signal_user9             (1ull << 57)
-#define j6_signal_user10            (1ull << 58)
-#define j6_signal_user11            (1ull << 59)
-#define j6_signal_user12            (1ull << 60)
-#define j6_signal_user13            (1ull << 61)
-#define j6_signal_user14            (1ull << 62)
-#define j6_signal_user15            (1ull << 63)
-
-#define j6_signal_user_mask         (0xffffull << 48)