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/*

 * Copyright 2005, Red Hat, Inc., Ingo Molnar

 * Released under the General Public License (GPL).

 *

 * This file contains the spinlock/rwlock implementations for

 * DEBUG_SPINLOCK.

 */

#include <linux/spinlock.h>

#include <linux/nmi.h>

#include <linux/interrupt.h>

#include <linux/debug_locks.h>

#include <linux/delay.h>

#include <linux/module.h>

void __spin_lock_init(spinlock_t *lock, const char *name,

                      struct lock_class_key *key)

{

#ifdef CONFIG_DEBUG_LOCK_ALLOC

        /*

         * Make sure we are not reinitializing a held lock:

         */

        debug_check_no_locks_freed((void *)lock, sizeof(*lock));

        lockdep_init_map(&lock->dep_map, name, key, 0);

#endif

        lock->raw_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;

        lock->magic = SPINLOCK_MAGIC;

        lock->owner = SPINLOCK_OWNER_INIT;

        lock->owner_cpu = -1;

}

EXPORT_SYMBOL(__spin_lock_init);

void __rwlock_init(rwlock_t *lock, const char *name,

                   struct lock_class_key *key)

{

#ifdef CONFIG_DEBUG_LOCK_ALLOC

        /*

         * Make sure we are not reinitializing a held lock:

         */

        debug_check_no_locks_freed((void *)lock, sizeof(*lock));

        lockdep_init_map(&lock->dep_map, name, key, 0);

#endif

        lock->raw_lock = (raw_rwlock_t) __RAW_RW_LOCK_UNLOCKED;

        lock->magic = RWLOCK_MAGIC;

        lock->owner = SPINLOCK_OWNER_INIT;

        lock->owner_cpu = -1;

}

EXPORT_SYMBOL(__rwlock_init);

static void spin_bug(spinlock_t *lock, const char *msg)

{

        struct task_struct *owner = NULL;

        if (!debug_locks_off())

                return;

        if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)

                owner = lock->owner;

        printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n",

                msg, raw_smp_processor_id(),

                current->comm, task_pid_nr(current));

        printk(KERN_EMERG " lock: %p, .magic: %08x, .owner: %s/%d, "

                        ".owner_cpu: %d\n",

                lock, lock->magic,

                owner ? owner->comm : "<none>",

                owner ? task_pid_nr(owner) : -1,

                lock->owner_cpu);

        dump_stack();

}

#define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg)

static inline void

debug_spin_lock_before(spinlock_t *lock)

{

        SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");

        SPIN_BUG_ON(lock->owner == current, lock, "recursion");

        SPIN_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),

                                                        lock, "cpu recursion");

}

static inline void debug_spin_lock_after(spinlock_t *lock)

{

        lock->owner_cpu = raw_smp_processor_id();

        lock->owner = current;

}

static inline void debug_spin_unlock(spinlock_t *lock)

{

        SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");

        SPIN_BUG_ON(!spin_is_locked(lock), lock, "already unlocked");

        SPIN_BUG_ON(lock->owner != current, lock, "wrong owner");

        SPIN_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),

                                                        lock, "wrong CPU");

        lock->owner = SPINLOCK_OWNER_INIT;

        lock->owner_cpu = -1;

}

static void __spin_lock_debug(spinlock_t *lock)

{

        u64 i;

        u64 loops = loops_per_jiffy * HZ;

        int print_once = 1;

        for (;;) {

                for (i = 0; i < loops; i++) {

                        if (__raw_spin_trylock(&lock->raw_lock))

                                return;

                        __delay(1);

                }

                /* lockup suspected: */

                if (print_once) {

                        print_once = 0;

                        printk(KERN_EMERG "BUG: spinlock lockup on CPU#%d, "

                                        "%s/%d, %p\n",

                                raw_smp_processor_id(), current->comm,

                                task_pid_nr(current), lock);

                        dump_stack();

#ifdef CONFIG_SMP

                        trigger_all_cpu_backtrace();

#endif

                }

        }

}

void _raw_spin_lock(spinlock_t *lock)

{

        debug_spin_lock_before(lock);

        if (unlikely(!__raw_spin_trylock(&lock->raw_lock)))

                __spin_lock_debug(lock);

        debug_spin_lock_after(lock);

}

int _raw_spin_trylock(spinlock_t *lock)

{

        int ret = __raw_spin_trylock(&lock->raw_lock);

        if (ret)

                debug_spin_lock_after(lock);

#ifndef CONFIG_SMP

        /*

         * Must not happen on UP:

         */

        SPIN_BUG_ON(!ret, lock, "trylock failure on UP");

#endif

        return ret;

}

void _raw_spin_unlock(spinlock_t *lock)

{

        debug_spin_unlock(lock);

        __raw_spin_unlock(&lock->raw_lock);

}

static void rwlock_bug(rwlock_t *lock, const char *msg)

{

        if (!debug_locks_off())

                return;

        printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n",

                msg, raw_smp_processor_id(), current->comm,

                task_pid_nr(current), lock);

        dump_stack();

}

#define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)

#if 0           /* __write_lock_debug() can lock up - maybe this can too? */

static void __read_lock_debug(rwlock_t *lock)

{

        u64 i;

        u64 loops = loops_per_jiffy * HZ;

        int print_once = 1;

        for (;;) {

                for (i = 0; i < loops; i++) {

                        if (__raw_read_trylock(&lock->raw_lock))

                                return;

                        __delay(1);

                }

                /* lockup suspected: */

                if (print_once) {

                        print_once = 0;

                        printk(KERN_EMERG "BUG: read-lock lockup on CPU#%d, "

                                        "%s/%d, %p\n",

                                raw_smp_processor_id(), current->comm,

                                current->pid, lock);

                        dump_stack();

                }

        }

}

#endif

void _raw_read_lock(rwlock_t *lock)

{

        RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");

        __raw_read_lock(&lock->raw_lock);

}

int _raw_read_trylock(rwlock_t *lock)

{

        int ret = __raw_read_trylock(&lock->raw_lock);

#ifndef CONFIG_SMP

        /*

         * Must not happen on UP:

         */

        RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");

#endif

        return ret;

}

void _raw_read_unlock(rwlock_t *lock)

{

        RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");

        __raw_read_unlock(&lock->raw_lock);

}

static inline void debug_write_lock_before(rwlock_t *lock)

{

        RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");

        RWLOCK_BUG_ON(lock->owner == current, lock, "recursion");

        RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),

                                                        lock, "cpu recursion");

}

static inline void debug_write_lock_after(rwlock_t *lock)

{

        lock->owner_cpu = raw_smp_processor_id();

        lock->owner = current;

}

static inline void debug_write_unlock(rwlock_t *lock)

{

        RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");

        RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner");

        RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),

                                                        lock, "wrong CPU");

        lock->owner = SPINLOCK_OWNER_INIT;

        lock->owner_cpu = -1;

}

#if 0           /* This can cause lockups */

static void __write_lock_debug(rwlock_t *lock)

{

        u64 i;

        u64 loops = loops_per_jiffy * HZ;

        int print_once = 1;

        for (;;) {

                for (i = 0; i < loops; i++) {

                        if (__raw_write_trylock(&lock->raw_lock))

                                return;

                        __delay(1);

                }

                /* lockup suspected: */

                if (print_once) {

                        print_once = 0;

                        printk(KERN_EMERG "BUG: write-lock lockup on CPU#%d, "

                                        "%s/%d, %p\n",

                                raw_smp_processor_id(), current->comm,

                                current->pid, lock);

                        dump_stack();

                }

        }

}

#endif

void _raw_write_lock(rwlock_t *lock)

{

        debug_write_lock_before(lock);

        __raw_write_lock(&lock->raw_lock);

        debug_write_lock_after(lock);

}

int _raw_write_trylock(rwlock_t *lock)

{

        int ret = __raw_write_trylock(&lock->raw_lock);

        if (ret)

                debug_write_lock_after(lock);

#ifndef CONFIG_SMP

        /*

         * Must not happen on UP:

         */

        RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");

#endif

        return ret;

}

void _raw_write_unlock(rwlock_t *lock)

{

        debug_write_unlock(lock);

        __raw_write_unlock(&lock->raw_lock);

}