Add kernel/notifier.c (fe9d4f57) · Commits · 戴 / test

include/linux/notifier.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -240,5 +240,7 @@ static inline int notifier_to_errno(int ret)
		#define KBD_KEYSYM 0x0004 /* Keyboard keysym */
		#define KBD_POST_KEYSYM 0x0005 /* Called after keyboard keysym interpretation */

		extern struct blocking_notifier_head reboot_notifier_list;

		#endif /* __KERNEL__ */
		#endif /* _LINUX_NOTIFIER_H */

kernel/Makefile

+2 −2

Original line number	Diff line number	Diff line
		@@ -8,8 +8,8 @@ obj-y = sched.o fork.o exec_domain.o panic.o printk.o profile.o \
		signal.o sys.o kmod.o workqueue.o pid.o \
		rcupdate.o extable.o params.o posix-timers.o \
		kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \
		hrtimer.o rwsem.o latency.o nsproxy.o srcu.o die_notifier.o \
		utsname.o sysctl_check.o
		hrtimer.o rwsem.o latency.o nsproxy.o srcu.o \
		utsname.o sysctl_check.o notifier.o

		obj-$(CONFIG_STACKTRACE) += stacktrace.o
		obj-y += time/

kernel/die_notifier.c

deleted100644 → 0

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		#include <linux/module.h>
		#include <linux/notifier.h>
		#include <linux/vmalloc.h>
		#include <linux/kdebug.h>


		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);

kernel/notifier.c

0 → 100644

+539 −0

Original line number	Diff line number	Diff line
		#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);

kernel/sys.c

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