2.6.24

 kernel

diff --git a/kernel/notifier.c b/kernel/notifier.c
new file mode 100644
index 0000000..4253f47
--- /dev/null
+++ b/kernel/notifier.c
@@ -0,0 +1,539 @@
+#include <linux/kdebug.h>
+#include <linux/kprobes.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/rcupdate.h>
+#include <linux/vmalloc.h>
+
+/*
+ *   Notifier list for kernel code which wants to be called
+ *   at shutdown. This is used to stop any idling DMA operations
+ *   and the like.
+ */
+BLOCKING_NOTIFIER_HEAD(reboot_notifier_list);
+
+/*
+ *   Notifier chain core routines.  The exported routines below
+ *   are layered on top of these, with appropriate locking added.
+ */
+
+static int notifier_chain_register(struct notifier_block **nl,
+      struct notifier_block *n)
+{
+   while ((*nl) != NULL) {
+      if (n->priority > (*nl)->priority)
+         break;
+      nl = &((*nl)->next);
+   }
+   n->next = *nl;
+   rcu_assign_pointer(*nl, n);
+   return 0;
+}
+
+static int notifier_chain_unregister(struct notifier_block **nl,
+      struct notifier_block *n)
+{
+   while ((*nl) != NULL) {
+      if ((*nl) == n) {
+         rcu_assign_pointer(*nl, n->next);
+         return 0;
+      }
+      nl = &((*nl)->next);
+   }
+   return -ENOENT;
+}
+
+/**
+ * notifier_call_chain - Informs the registered notifiers about an event.
+ *   @nl:      Pointer to head of the blocking notifier chain
+ *   @val:      Value passed unmodified to notifier function
+ *   @v:      Pointer passed unmodified to notifier function
+ *   @nr_to_call:   Number of notifier functions to be called. Don't care
+ *         value of this parameter is -1.
+ *   @nr_calls:   Records the number of notifications sent. Don't care
+ *         value of this field is NULL.
+ *   @returns:   notifier_call_chain returns the value returned by the
+ *         last notifier function called.
+ */
+static int __kprobes notifier_call_chain(struct notifier_block **nl,
+               unsigned long val, void *v,
+               int nr_to_call,   int *nr_calls)
+{
+   int ret = NOTIFY_DONE;
+   struct notifier_block *nb, *next_nb;
+
+   nb = rcu_dereference(*nl);
+
+   while (nb && nr_to_call) {
+      next_nb = rcu_dereference(nb->next);
+      ret = nb->notifier_call(nb, val, v);
+
+      if (nr_calls)
+         (*nr_calls)++;
+
+      if ((ret & NOTIFY_STOP_MASK) == NOTIFY_STOP_MASK)
+         break;
+      nb = next_nb;
+      nr_to_call--;
+   }
+   return ret;
+}
+
+/*
+ *   Atomic notifier chain routines.  Registration and unregistration
+ *   use a spinlock, and call_chain is synchronized by RCU (no locks).
+ */
+
+/**
+ *   atomic_notifier_chain_register - Add notifier to an atomic notifier chain
+ *   @nh: Pointer to head of the atomic notifier chain
+ *   @n: New entry in notifier chain
+ *
+ *   Adds a notifier to an atomic notifier chain.
+ *
+ *   Currently always returns zero.
+ */
+int atomic_notifier_chain_register(struct atomic_notifier_head *nh,
+      struct notifier_block *n)
+{
+   unsigned long flags;
+   int ret;
+
+   spin_lock_irqsave(&nh->lock, flags);
+   ret = notifier_chain_register(&nh->head, n);
+   spin_unlock_irqrestore(&nh->lock, flags);
+   return ret;
+}
+EXPORT_SYMBOL_GPL(atomic_notifier_chain_register);
+
+/**
+ *   atomic_notifier_chain_unregister - Remove notifier from an atomic notifier chain
+ *   @nh: Pointer to head of the atomic notifier chain
+ *   @n: Entry to remove from notifier chain
+ *
+ *   Removes a notifier from an atomic notifier chain.
+ *
+ *   Returns zero on success or %-ENOENT on failure.
+ */
+int atomic_notifier_chain_unregister(struct atomic_notifier_head *nh,
+      struct notifier_block *n)
+{
+   unsigned long flags;
+   int ret;
+
+   spin_lock_irqsave(&nh->lock, flags);
+   ret = notifier_chain_unregister(&nh->head, n);
+   spin_unlock_irqrestore(&nh->lock, flags);
+   synchronize_rcu();
+   return ret;
+}
+EXPORT_SYMBOL_GPL(atomic_notifier_chain_unregister);
+
+/**
+ *   __atomic_notifier_call_chain - Call functions in an atomic notifier chain
+ *   @nh: Pointer to head of the atomic notifier chain
+ *   @val: Value passed unmodified to notifier function
+ *   @v: Pointer passed unmodified to notifier function
+ *   @nr_to_call: See the comment for notifier_call_chain.
+ *   @nr_calls: See the comment for notifier_call_chain.
+ *
+ *   Calls each function in a notifier chain in turn.  The functions
+ *   run in an atomic context, so they must not block.
+ *   This routine uses RCU to synchronize with changes to the chain.
+ *
+ *   If the return value of the notifier can be and'ed
+ *   with %NOTIFY_STOP_MASK then atomic_notifier_call_chain()
+ *   will return immediately, with the return value of
+ *   the notifier function which halted execution.
+ *   Otherwise the return value is the return value
+ *   of the last notifier function called.
+ */
+int __kprobes __atomic_notifier_call_chain(struct atomic_notifier_head *nh,
+               unsigned long val, void *v,
+               int nr_to_call, int *nr_calls)
+{
+   int ret;
+
+   rcu_read_lock();
+   ret = notifier_call_chain(&nh->head, val, v, nr_to_call, nr_calls);
+   rcu_read_unlock();
+   return ret;
+}
+EXPORT_SYMBOL_GPL(__atomic_notifier_call_chain);
+
+int __kprobes atomic_notifier_call_chain(struct atomic_notifier_head *nh,
+      unsigned long val, void *v)
+{
+   return __atomic_notifier_call_chain(nh, val, v, -1, NULL);
+}
+EXPORT_SYMBOL_GPL(atomic_notifier_call_chain);
+
+/*
+ *   Blocking notifier chain routines.  All access to the chain is
+ *   synchronized by an rwsem.
+ */
+
+/**
+ *   blocking_notifier_chain_register - Add notifier to a blocking notifier chain
+ *   @nh: Pointer to head of the blocking notifier chain
+ *   @n: New entry in notifier chain
+ *
+ *   Adds a notifier to a blocking notifier chain.
+ *   Must be called in process context.
+ *
+ *   Currently always returns zero.
+ */
+int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
+      struct notifier_block *n)
+{
+   int ret;
+
+   /*
+    * This code gets used during boot-up, when task switching is
+    * not yet working and interrupts must remain disabled.  At
+    * such times we must not call down_write().
+    */
+   if (unlikely(system_state == SYSTEM_BOOTING))
+      return notifier_chain_register(&nh->head, n);
+
+   down_write(&nh->rwsem);
+   ret = notifier_chain_register(&nh->head, n);
+   up_write(&nh->rwsem);
+   return ret;
+}
+EXPORT_SYMBOL_GPL(blocking_notifier_chain_register);
+
+/**
+ *   blocking_notifier_chain_unregister - Remove notifier from a blocking notifier chain
+ *   @nh: Pointer to head of the blocking notifier chain
+ *   @n: Entry to remove from notifier chain
+ *
+ *   Removes a notifier from a blocking notifier chain.
+ *   Must be called from process context.
+ *
+ *   Returns zero on success or %-ENOENT on failure.
+ */
+int blocking_notifier_chain_unregister(struct blocking_notifier_head *nh,
+      struct notifier_block *n)
+{
+   int ret;
+
+   /*
+    * This code gets used during boot-up, when task switching is
+    * not yet working and interrupts must remain disabled.  At
+    * such times we must not call down_write().
+    */
+   if (unlikely(system_state == SYSTEM_BOOTING))
+      return notifier_chain_unregister(&nh->head, n);
+
+   down_write(&nh->rwsem);
+   ret = notifier_chain_unregister(&nh->head, n);
+   up_write(&nh->rwsem);
+   return ret;
+}
+EXPORT_SYMBOL_GPL(blocking_notifier_chain_unregister);
+
+/**
+ *   __blocking_notifier_call_chain - Call functions in a blocking notifier chain
+ *   @nh: Pointer to head of the blocking notifier chain
+ *   @val: Value passed unmodified to notifier function
+ *   @v: Pointer passed unmodified to notifier function
+ *   @nr_to_call: See comment for notifier_call_chain.
+ *   @nr_calls: See comment for notifier_call_chain.
+ *
+ *   Calls each function in a notifier chain in turn.  The functions
+ *   run in a process context, so they are allowed to block.
+ *
+ *   If the return value of the notifier can be and'ed
+ *   with %NOTIFY_STOP_MASK then blocking_notifier_call_chain()
+ *   will return immediately, with the return value of
+ *   the notifier function which halted execution.
+ *   Otherwise the return value is the return value
+ *   of the last notifier function called.
+ */
+int __blocking_notifier_call_chain(struct blocking_notifier_head *nh,
+               unsigned long val, void *v,
+               int nr_to_call, int *nr_calls)
+{
+   int ret = NOTIFY_DONE;
+
+   /*
+    * We check the head outside the lock, but if this access is
+    * racy then it does not matter what the result of the test
+    * is, we re-check the list after having taken the lock anyway:
+    */
+   if (rcu_dereference(nh->head)) {
+      down_read(&nh->rwsem);
+      ret = notifier_call_chain(&nh->head, val, v, nr_to_call,
+               nr_calls);
+      up_read(&nh->rwsem);
+   }
+   return ret;
+}
+EXPORT_SYMBOL_GPL(__blocking_notifier_call_chain);
+
+int blocking_notifier_call_chain(struct blocking_notifier_head *nh,
+      unsigned long val, void *v)
+{
+   return __blocking_notifier_call_chain(nh, val, v, -1, NULL);
+}
+EXPORT_SYMBOL_GPL(blocking_notifier_call_chain);
+
+/*
+ *   Raw notifier chain routines.  There is no protection;
+ *   the caller must provide it.  Use at your own risk!
+ */
+
+/**
+ *   raw_notifier_chain_register - Add notifier to a raw notifier chain
+ *   @nh: Pointer to head of the raw notifier chain
+ *   @n: New entry in notifier chain
+ *
+ *   Adds a notifier to a raw notifier chain.
+ *   All locking must be provided by the caller.
+ *
+ *   Currently always returns zero.
+ */
+int raw_notifier_chain_register(struct raw_notifier_head *nh,
+      struct notifier_block *n)
+{
+   return notifier_chain_register(&nh->head, n);
+}
+EXPORT_SYMBOL_GPL(raw_notifier_chain_register);
+
+/**
+ *   raw_notifier_chain_unregister - Remove notifier from a raw notifier chain
+ *   @nh: Pointer to head of the raw notifier chain
+ *   @n: Entry to remove from notifier chain
+ *
+ *   Removes a notifier from a raw notifier chain.
+ *   All locking must be provided by the caller.
+ *
+ *   Returns zero on success or %-ENOENT on failure.
+ */
+int raw_notifier_chain_unregister(struct raw_notifier_head *nh,
+      struct notifier_block *n)
+{
+   return notifier_chain_unregister(&nh->head, n);
+}
+EXPORT_SYMBOL_GPL(raw_notifier_chain_unregister);
+
+/**
+ *   __raw_notifier_call_chain - Call functions in a raw notifier chain
+ *   @nh: Pointer to head of the raw notifier chain
+ *   @val: Value passed unmodified to notifier function
+ *   @v: Pointer passed unmodified to notifier function
+ *   @nr_to_call: See comment for notifier_call_chain.
+ *   @nr_calls: See comment for notifier_call_chain
+ *
+ *   Calls each function in a notifier chain in turn.  The functions
+ *   run in an undefined context.
+ *   All locking must be provided by the caller.
+ *
+ *   If the return value of the notifier can be and'ed
+ *   with %NOTIFY_STOP_MASK then raw_notifier_call_chain()
+ *   will return immediately, with the return value of
+ *   the notifier function which halted execution.
+ *   Otherwise the return value is the return value
+ *   of the last notifier function called.
+ */
+int __raw_notifier_call_chain(struct raw_notifier_head *nh,
+               unsigned long val, void *v,
+               int nr_to_call, int *nr_calls)
+{
+   return notifier_call_chain(&nh->head, val, v, nr_to_call, nr_calls);
+}
+EXPORT_SYMBOL_GPL(__raw_notifier_call_chain);
+
+int raw_notifier_call_chain(struct raw_notifier_head *nh,
+      unsigned long val, void *v)
+{
+   return __raw_notifier_call_chain(nh, val, v, -1, NULL);
+}
+EXPORT_SYMBOL_GPL(raw_notifier_call_chain);
+
+/*
+ *   SRCU notifier chain routines.    Registration and unregistration
+ *   use a mutex, and call_chain is synchronized by SRCU (no locks).
+ */
+
+/**
+ *   srcu_notifier_chain_register - Add notifier to an SRCU notifier chain
+ *   @nh: Pointer to head of the SRCU notifier chain
+ *   @n: New entry in notifier chain
+ *
+ *   Adds a notifier to an SRCU notifier chain.
+ *   Must be called in process context.
+ *
+ *   Currently always returns zero.
+ */
+int srcu_notifier_chain_register(struct srcu_notifier_head *nh,
+      struct notifier_block *n)
+{
+   int ret;
+
+   /*
+    * This code gets used during boot-up, when task switching is
+    * not yet working and interrupts must remain disabled.  At
+    * such times we must not call mutex_lock().
+    */
+   if (unlikely(system_state == SYSTEM_BOOTING))
+      return notifier_chain_register(&nh->head, n);
+
+   mutex_lock(&nh->mutex);
+   ret = notifier_chain_register(&nh->head, n);
+   mutex_unlock(&nh->mutex);
+   return ret;
+}
+EXPORT_SYMBOL_GPL(srcu_notifier_chain_register);
+
+/**
+ *   srcu_notifier_chain_unregister - Remove notifier from an SRCU notifier chain
+ *   @nh: Pointer to head of the SRCU notifier chain
+ *   @n: Entry to remove from notifier chain
+ *
+ *   Removes a notifier from an SRCU notifier chain.
+ *   Must be called from process context.
+ *
+ *   Returns zero on success or %-ENOENT on failure.
+ */
+int srcu_notifier_chain_unregister(struct srcu_notifier_head *nh,
+      struct notifier_block *n)
+{
+   int ret;
+
+   /*
+    * This code gets used during boot-up, when task switching is
+    * not yet working and interrupts must remain disabled.  At
+    * such times we must not call mutex_lock().
+    */
+   if (unlikely(system_state == SYSTEM_BOOTING))
+      return notifier_chain_unregister(&nh->head, n);
+
+   mutex_lock(&nh->mutex);
+   ret = notifier_chain_unregister(&nh->head, n);
+   mutex_unlock(&nh->mutex);
+   synchronize_srcu(&nh->srcu);
+   return ret;
+}
+EXPORT_SYMBOL_GPL(srcu_notifier_chain_unregister);
+
+/**
+ *   __srcu_notifier_call_chain - Call functions in an SRCU notifier chain
+ *   @nh: Pointer to head of the SRCU notifier chain
+ *   @val: Value passed unmodified to notifier function
+ *   @v: Pointer passed unmodified to notifier function
+ *   @nr_to_call: See comment for notifier_call_chain.
+ *   @nr_calls: See comment for notifier_call_chain
+ *
+ *   Calls each function in a notifier chain in turn.  The functions
+ *   run in a process context, so they are allowed to block.
+ *
+ *   If the return value of the notifier can be and'ed
+ *   with %NOTIFY_STOP_MASK then srcu_notifier_call_chain()
+ *   will return immediately, with the return value of
+ *   the notifier function which halted execution.
+ *   Otherwise the return value is the return value
+ *   of the last notifier function called.
+ */
+int __srcu_notifier_call_chain(struct srcu_notifier_head *nh,
+                unsigned long val, void *v,
+                int nr_to_call, int *nr_calls)
+{
+   int ret;
+   int idx;
+
+   idx = srcu_read_lock(&nh->srcu);
+   ret = notifier_call_chain(&nh->head, val, v, nr_to_call, nr_calls);
+   srcu_read_unlock(&nh->srcu, idx);
+   return ret;
+}
+EXPORT_SYMBOL_GPL(__srcu_notifier_call_chain);
+
+int srcu_notifier_call_chain(struct srcu_notifier_head *nh,
+      unsigned long val, void *v)
+{
+   return __srcu_notifier_call_chain(nh, val, v, -1, NULL);
+}
+EXPORT_SYMBOL_GPL(srcu_notifier_call_chain);
+
+/**
+ *   srcu_init_notifier_head - Initialize an SRCU notifier head
+ *   @nh: Pointer to head of the srcu notifier chain
+ *
+ *   Unlike other sorts of notifier heads, SRCU notifier heads require
+ *   dynamic initialization.  Be sure to call this routine before
+ *   calling any of the other SRCU notifier routines for this head.
+ *
+ *   If an SRCU notifier head is deallocated, it must first be cleaned
+ *   up by calling srcu_cleanup_notifier_head().  Otherwise the head's
+ *   per-cpu data (used by the SRCU mechanism) will leak.
+ */
+void srcu_init_notifier_head(struct srcu_notifier_head *nh)
+{
+   mutex_init(&nh->mutex);
+   if (init_srcu_struct(&nh->srcu) < 0)
+      BUG();
+   nh->head = NULL;
+}
+EXPORT_SYMBOL_GPL(srcu_init_notifier_head);
+
+/**
+ *   register_reboot_notifier - Register function to be called at reboot time
+ *   @nb: Info about notifier function to be called
+ *
+ *   Registers a function with the list of functions
+ *   to be called at reboot time.
+ *
+ *   Currently always returns zero, as blocking_notifier_chain_register()
+ *   always returns zero.
+ */
+int register_reboot_notifier(struct notifier_block *nb)
+{
+   return blocking_notifier_chain_register(&reboot_notifier_list, nb);
+}
+EXPORT_SYMBOL(register_reboot_notifier);
+
+/**
+ *   unregister_reboot_notifier - Unregister previously registered reboot notifier
+ *   @nb: Hook to be unregistered
+ *
+ *   Unregisters a previously registered reboot
+ *   notifier function.
+ *
+ *   Returns zero on success, or %-ENOENT on failure.
+ */
+int unregister_reboot_notifier(struct notifier_block *nb)
+{
+   return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
+}
+EXPORT_SYMBOL(unregister_reboot_notifier);
+
+static ATOMIC_NOTIFIER_HEAD(die_chain);
+
+int notify_die(enum die_val val, const char *str,
+          struct pt_regs *regs, long err, int trap, int sig)
+{
+   struct die_args args = {
+      .regs   = regs,
+      .str   = str,
+      .err   = err,
+      .trapnr   = trap,
+      .signr   = sig,
+
+   };
+   return atomic_notifier_call_chain(&die_chain, val, &args);
+}
+
+int register_die_notifier(struct notifier_block *nb)
+{
+   vmalloc_sync_all();
+   return atomic_notifier_chain_register(&die_chain, nb);
+}
+EXPORT_SYMBOL_GPL(register_die_notifier);
+
+int unregister_die_notifier(struct notifier_block *nb)
+{
+   return atomic_notifier_chain_unregister(&die_chain, nb);
+}
+EXPORT_SYMBOL_GPL(unregister_die_notifier);