cp/nucleus/ldep.c

   1 /*
   2  * (C) Copyright 2007-2011  Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
   3  *
   4  * This file is released under the GPLv2.  See the COPYING file for more
   5  * details.
   6  */
   7
   8 #include <sched.h>
   9 #include <list.h>
  10 #include <spinlock.h>
  11 #include <ldep.h>
  12
  13 static spinlock_t __lock = SPIN_LOCK_UNLOCKED;
  14 static int ldep_enabled;
  15
  16 void ldep_on()
  17 {
  18         unsigned long mask;
  19
  20         spin_lock_intsave(&__lock, &mask);
  21         ldep_enabled = 1;
  22         spin_unlock_intrestore(&__lock, mask);
  23 }
  24
  25 static int __get_stack_slot()
  26 {
  27         current->nr_locks++;
  28
  29         if (current->nr_locks == LDEP_STACK_SIZE) {
  30                 con_printf(NULL, "task '%s' exceeded the number of tracked "
  31                            "locks (%d)! disabling ldep!\n", current->name,
  32                            LDEP_STACK_SIZE);
  33                 return 1;
  34         }
  35
  36         return 0;
  37 }
  38
  39 static void print_held_locks()
  40 {
  41         struct held_lock *cur;
  42         int i;
  43
  44         con_printf(NULL, "\nlocks currently held:\n");
  45         for(i=0; i<current->nr_locks; i++) {
  46                 cur = &current->lock_stack[i];
  47                 con_printf(NULL, " #%d:   (%s), at %p\n", i, cur->lockname,
  48                        cur->ra);
  49         }
  50 }
  51
  52 void ldep_lock(void *lock, struct lock_class *c, char *lockname)
  53 {
  54         void *ra = __builtin_return_address(0);
  55         struct held_lock *cur;
  56         unsigned long mask;
  57
  58         // LOCK
  59         spin_lock_intsave(&__lock, &mask);
  60
  61         if (!ldep_enabled)
  62                 goto out;
  63
  64         /* ok, no issues, add the lock we're trying to get to the stack */
  65         if (__get_stack_slot())
  66                 goto out;
  67
  68         cur = &current->lock_stack[current->nr_locks-1];
  69         cur->ra = ra;
  70         cur->lock = lock;
  71         cur->lockname = lockname;
  72
  73 out:
  74         // UNLOCK
  75         spin_unlock_intrestore(&__lock, mask);
  76 }
  77
  78 void ldep_unlock(void *lock, char *lockname)
  79 {
  80         void *ra = __builtin_return_address(0);
  81         struct held_lock *cur;
  82         unsigned long mask;
  83         int i;
  84
  85         // LOCK
  86         spin_lock_intsave(&__lock, &mask);
  87
  88         if (!ldep_enabled)
  89                 goto out;
  90
  91         for(i=0; i<current->nr_locks; i++) {
  92                 cur = &current->lock_stack[i];
  93                 if (cur->lock == lock)
  94                         goto found;
  95         }
  96
  97         con_printf(NULL, "task '%s' is trying to release lock it doesn't have:\n",
  98                    current->name);
  99         con_printf(NULL, " (%s), at %p\n", lockname, ra);
 100         print_held_locks();
 101
 102         ldep_enabled = 0;
 103
 104         goto out;
 105
 106 found:
 107         if (i != current->nr_locks-1)
 108                 memcpy(&current->lock_stack[i],
 109                        &current->lock_stack[i+1],
 110                        current->nr_locks - i - 1);
 111
 112         current->nr_locks--;
 113
 114 out:
 115         // UNLOCK
 116         spin_unlock_intrestore(&__lock, mask);
 117 }
 118
 119 void ldep_no_locks()
 120 {
 121         void *ra = __builtin_return_address(0);
 122         unsigned long mask;
 123
 124         // LOCK
 125         spin_lock_intsave(&__lock, &mask);
 126
 127         if (!ldep_enabled)
 128                 goto out;
 129
 130         if (!current->nr_locks)
 131                 goto out;
 132
 133         con_printf(NULL, "task '%s' is holding a lock when it shouldn't have:\n",
 134                    current->name);
 135         con_printf(NULL, " at %p\n", ra);
 136         print_held_locks();
 137
 138         ldep_enabled = 0;
 139
 140 out:
 141         // UNLOCK
 142         spin_unlock_intrestore(&__lock, mask);
 143 }