Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 * RT-Mutexes: blocking mutual exclusion locks with PI support

 *

 * started by Ingo Molnar and Thomas Gleixner:

 *

 *  Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>

 *  Copyright (C) 2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>

 *

 * This code is based on the rt.c implementation in the preempt-rt tree.

 * Portions of said code are

 *

 *  Copyright (C) 2004  LynuxWorks, Inc., Igor Manyilov, Bill Huey

 *  Copyright (C) 2006  Esben Nielsen

 *  Copyright (C) 2006  Kihon Technologies Inc.,

 *                      Steven Rostedt <rostedt@goodmis.org>

 *

 * See rt.c in preempt-rt for proper credits and further information

 */

#include <linux/sched.h>

#include <linux/delay.h>

#include <linux/module.h>

#include <linux/spinlock.h>

#include <linux/kallsyms.h>

#include <linux/syscalls.h>

#include <linux/interrupt.h>

#include <linux/plist.h>

#include <linux/fs.h>

#include <linux/debug_locks.h>

#include "rtmutex_common.h"

# define TRACE_WARN_ON(x)                       WARN_ON(x)

# define TRACE_BUG_ON(x)                        BUG_ON(x)

# define TRACE_OFF()                                            \

do {                                                            \

        if (rt_trace_on) {                                      \

                rt_trace_on = 0;                         \

                console_verbose();                              \

                if (spin_is_locked(&current->pi_lock))          \

                        spin_unlock(&current->pi_lock);         \

        }                                                       \

} while (0)

# define TRACE_OFF_NOLOCK()                                     \

do {                                                            \

        if (rt_trace_on) {                                      \

                rt_trace_on = 0;                         \

                console_verbose();                              \

        }                                                       \

} while (0)

# define TRACE_BUG_LOCKED()                     \

do {                                            \

        TRACE_OFF();                            \

        BUG();                                  \

} while (0)

# define TRACE_WARN_ON_LOCKED(c)                \

do {                                            \

        if (unlikely(c)) {                      \

                TRACE_OFF();                    \

                WARN_ON(1);                     \

        }                                       \

} while (0)

# define TRACE_BUG_ON_LOCKED(c)                 \

do {                                            \

        if (unlikely(c))                        \

                TRACE_BUG_LOCKED();             \

} while (0)

#ifdef CONFIG_SMP

# define SMP_TRACE_BUG_ON_LOCKED(c)     TRACE_BUG_ON_LOCKED(c)

#else

# define SMP_TRACE_BUG_ON_LOCKED(c)     do { } while (0)

#endif

/*

 * deadlock detection flag. We turn it off when we detect

 * the first problem because we dont want to recurse back

 * into the tracing code when doing error printk or

 * executing a BUG():

 */

static int rt_trace_on = 1;

static void printk_task(struct task_struct *p)

{

        if (p)

                printk("%16s:%5d [%p, %3d]", p->comm, task_pid_nr(p), p, p->prio);

        else

                printk("<none>");

}

static void printk_lock(struct rt_mutex *lock, int print_owner)

{

        if (lock->name)

                printk(" [%p] {%s}\n",

                        lock, lock->name);

        else

                printk(" [%p] {%s:%d}\n",

                        lock, lock->file, lock->line);

        if (print_owner && rt_mutex_owner(lock)) {

                printk(".. ->owner: %p\n", lock->owner);

                printk(".. held by:  ");

                printk_task(rt_mutex_owner(lock));

                printk("\n");

        }

}

void rt_mutex_debug_task_free(struct task_struct *task)

{

        WARN_ON(!plist_head_empty(&task->pi_waiters));

        WARN_ON(task->pi_blocked_on);

}

/*

 * We fill out the fields in the waiter to store the information about

 * the deadlock. We print when we return. act_waiter can be NULL in

 * case of a remove waiter operation.

 */

void debug_rt_mutex_deadlock(int detect, struct rt_mutex_waiter *act_waiter,

                             struct rt_mutex *lock)

{

        struct task_struct *task;

        if (!rt_trace_on || detect || !act_waiter)

                return;

        task = rt_mutex_owner(act_waiter->lock);

        if (task && task != current) {

                act_waiter->deadlock_task_pid = task->pid;

                act_waiter->deadlock_lock = lock;

        }

}

void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter)

{

        struct task_struct *task;

        if (!waiter->deadlock_lock || !rt_trace_on)

                return;

        task = find_task_by_pid(waiter->deadlock_task_pid);

        if (!task)

                return;

        TRACE_OFF_NOLOCK();

        printk("\n============================================\n");

        printk(  "[ BUG: circular locking deadlock detected! ]\n");

        printk(  "--------------------------------------------\n");

        printk("%s/%d is deadlocking current task %s/%d\n\n",

               task->comm, task_pid_nr(task),

               current->comm, task_pid_nr(current));

        printk("\n1) %s/%d is trying to acquire this lock:\n",

               current->comm, task_pid_nr(current));

        printk_lock(waiter->lock, 1);

        printk("\n2) %s/%d is blocked on this lock:\n",

                task->comm, task_pid_nr(task));

        printk_lock(waiter->deadlock_lock, 1);

        debug_show_held_locks(current);

        debug_show_held_locks(task);

        printk("\n%s/%d's [blocked] stackdump:\n\n",

                task->comm, task_pid_nr(task));

        show_stack(task, NULL);

        printk("\n%s/%d's [current] stackdump:\n\n",

                current->comm, task_pid_nr(current));

        dump_stack();

        debug_show_all_locks();

        printk("[ turning off deadlock detection."

               "Please report this trace. ]\n\n");

        local_irq_disable();

}

void debug_rt_mutex_lock(struct rt_mutex *lock)

{

}

void debug_rt_mutex_unlock(struct rt_mutex *lock)

{

        TRACE_WARN_ON_LOCKED(rt_mutex_owner(lock) != current);

}

void

debug_rt_mutex_proxy_lock(struct rt_mutex *lock, struct task_struct *powner)

{

}

void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock)

{

        TRACE_WARN_ON_LOCKED(!rt_mutex_owner(lock));

}

void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)

{

        memset(waiter, 0x11, sizeof(*waiter));

        plist_node_init(&waiter->list_entry, MAX_PRIO);

        plist_node_init(&waiter->pi_list_entry, MAX_PRIO);

}

void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)

{

        TRACE_WARN_ON(!plist_node_empty(&waiter->list_entry));

        TRACE_WARN_ON(!plist_node_empty(&waiter->pi_list_entry));

        TRACE_WARN_ON(waiter->task);

        memset(waiter, 0x22, sizeof(*waiter));

}

void debug_rt_mutex_init(struct rt_mutex *lock, const char *name)

{

        /*

         * Make sure we are not reinitializing a held lock:

         */

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

        lock->name = name;

}

void

rt_mutex_deadlock_account_lock(struct rt_mutex *lock, struct task_struct *task)

{

}

void rt_mutex_deadlock_account_unlock(struct task_struct *task)

{

}