Import raw notifier subsystem from Linux.

Signed-off-by: Keir Fraser <keir.fraser@citrix.com>

1 files changed, 89 insertions, 0 deletions

diff --git a/xen/include/xen/notifier.h b/xen/include/xen/notifier.h
new file mode 100644
index 0000000000..84ec50f92b
--- /dev/null
+++ b/xen/include/xen/notifier.h
@@ -0,0 +1,89 @@
+/******************************************************************************
+ * include/xen/notifier.h
+ *
+ * Routines to manage notifier chains for passing status changes to any
+ * interested routines.
+ *
+ * Original code from Linux kernel 2.6.27 (Alan Cox <Alan.Cox@linux.org>)
+ */
+ 
+#ifndef __XEN_NOTIFIER_H__
+#define __XEN_NOTIFIER_H__
+
+#include <xen/config.h>
+#include <xen/types.h>
+#include <xen/errno.h>
+
+/*
+ * Xen includes only one type of notifier chains inherited from Linux:
+ *     Raw notifier chains: There are no restrictions on callbacks,
+ *        registration, or unregistration.  All locking and protection
+ *        must be provided by the caller.
+ */
+
+struct notifier_block {
+    int (*notifier_call)(struct notifier_block *, unsigned long, void *);
+    struct notifier_block *next;
+    int priority;
+};
+
+struct raw_notifier_head {
+    struct notifier_block *head;
+};
+
+#define RAW_INIT_NOTIFIER_HEAD(name) do {       \
+    (name)->head = NULL;                        \
+} while (0)
+
+#define RAW_NOTIFIER_INIT(name) { .head = NULL }
+
+#define RAW_NOTIFIER_HEAD(name) \
+    struct raw_notifier_head name = RAW_NOTIFIER_INIT(name)
+
+int raw_notifier_chain_register(
+    struct raw_notifier_head *nh, struct notifier_block *nb);
+
+int raw_notifier_chain_unregister(
+    struct raw_notifier_head *nh, struct notifier_block *nb);
+
+int raw_notifier_call_chain(
+    struct raw_notifier_head *nh, unsigned long val, void *v);
+int __raw_notifier_call_chain(
+    struct raw_notifier_head *nh, unsigned long val, void *v,
+    int nr_to_call, int *nr_calls);
+
+#define NOTIFY_DONE  0x0000  /* Don't care */
+#define NOTIFY_OK  0x0001  /* Suits me */
+#define NOTIFY_STOP_MASK 0x8000  /* Don't call further */
+#define NOTIFY_BAD  (NOTIFY_STOP_MASK|0x0002)
+/* Bad/Veto action */
+/*
+ * Clean way to return from the notifier and stop further calls.
+ */
+#define NOTIFY_STOP  (NOTIFY_OK|NOTIFY_STOP_MASK)
+
+/* Encapsulate (negative) errno value (in particular, NOTIFY_BAD <=> EPERM). */
+static inline int notifier_from_errno(int err)
+{
+    return NOTIFY_STOP_MASK | (NOTIFY_OK - err);
+}
+
+/* Restore (negative) errno value from notify return value. */
+static inline int notifier_to_errno(int ret)
+{
+    ret &= ~NOTIFY_STOP_MASK;
+    return ret > NOTIFY_OK ? NOTIFY_OK - ret : 0;
+}
+
+#define CPU_ONLINE  0x0002 /* CPU (unsigned)v is up */
+#define CPU_UP_PREPARE  0x0003 /* CPU (unsigned)v coming up */
+#define CPU_UP_CANCELED  0x0004 /* CPU (unsigned)v NOT coming up */
+#define CPU_DOWN_PREPARE 0x0005 /* CPU (unsigned)v going down */
+#define CPU_DOWN_FAILED  0x0006 /* CPU (unsigned)v NOT going down */
+#define CPU_DEAD  0x0007 /* CPU (unsigned)v dead */
+#define CPU_DYING  0x0008 /* CPU (unsigned)v not running any task,
+                           * not handling interrupts, soon dead */
+#define CPU_POST_DEAD  0x0009 /* CPU (unsigned)v dead, cpu_hotplug
+                               * lock is dropped */
+
+#endif /* __XEN_NOTIFIER_H__ */