posix clocks: Replace mutex with reader/writer semaphore

[pandora-kernel.git] / include / xen / gntdev.h

diff --git a/include/xen/gntdev.h b/include/xen/gntdev.h
index eb23f41..5304bd3 100644 (file)
--- a/include/xen/gntdev.h
+++ b/include/xen/gntdev.h
@@ -116,4 +116,35 @@ struct ioctl_gntdev_set_max_grants {
        uint32_t count;
 };
 
+/*
+ * Sets up an unmap notification within the page, so that the other side can do
+ * cleanup if this side crashes. Required to implement cross-domain robust
+ * mutexes or close notification on communication channels.
+ *
+ * Each mapped page only supports one notification; multiple calls referring to
+ * the same page overwrite the previous notification. You must clear the
+ * notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it
+ * to occur.
+ */
+#define IOCTL_GNTDEV_SET_UNMAP_NOTIFY \
+_IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntdev_unmap_notify))
+struct ioctl_gntdev_unmap_notify {
+       /* IN parameters */
+       /* Offset in the file descriptor for a byte within the page (same as
+        * used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to
+        * be cleared. Otherwise, it can be any byte in the page whose
+        * notification we are adjusting.
+        */
+       uint64_t index;
+       /* Action(s) to take on unmap */
+       uint32_t action;
+       /* Event channel to notify */
+       uint32_t event_channel_port;
+};
+
+/* Clear (set to zero) the byte specified by index */
+#define UNMAP_NOTIFY_CLEAR_BYTE 0x1
+/* Send an interrupt on the indicated event channel */
+#define UNMAP_NOTIFY_SEND_EVENT 0x2
+
 #endif /* __LINUX_PUBLIC_GNTDEV_H__ */