Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

#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);