kernel/include/kern/spinlock.h

   1 #ifndef _KERN_SPINLOCK_H
   2 #define _KERN_SPINLOCK_H
   3
   4 #include <kern/kernel.h>
   5 #include <lowlevel/misc.h>
   6
   7 extern int dying;
   8
   9 namespace Lock {
  10         struct SpinLock {
  11                 #if CONF_DEBUG_SPINLOCKS
  12                         unsigned long held_at;
  13                 #endif
  14
  15                 SpinLock()
  16                 {
  17                         init();
  18                 }
  19
  20                 void init()
  21                 {
  22                         // Nothing on UP.  Call arch on SMP.
  23
  24                         #if CONF_DEBUG_SPINLOCKS
  25                                 held_at = 0;
  26                         #endif
  27                 }
  28
  29                 void lock()
  30                 {
  31                         // Nothing on UP.  Call arch on SMP.
  32
  33                         #if CONF_DEBUG_SPINLOCKS
  34                                 #if !CONF_SMP
  35                                         if (!in_fault && held_at) {
  36                                                 in_fault++;
  37                                                 printf("Spinlock deadlock, lock %p previously held at 0x%lx\n",
  38                                                        this, held_at);
  39                                                 in_fault--;
  40                                                 BUG();
  41                                         }
  42                                 #endif
  43
  44                                 held_at = (ulong)__builtin_return_address(0);
  45                         #endif
  46                 }
  47
  48                 void unlock()
  49                 {
  50                         #if CONF_DEBUG_SPINLOCKS
  51                                 held_at = 0;
  52                         #endif
  53
  54                         // Nothing on UP.  Call arch on SMP.
  55                 }
  56
  57                 void lock_irq()
  58                 {
  59                         ll_ints_off();
  60                         lock();
  61                 }
  62
  63                 void unlock_irq()
  64                 {
  65                         unlock();
  66                         ll_ints_on();
  67                 }
  68
  69                 ulong lock_recirq()
  70                 {
  71                         unsigned long ret = ll_ints_save_and_off();
  72                         lock();
  73                         return ret;
  74                 }
  75
  76                 void unlock_recirq(ulong savedirq)
  77                 {
  78                         unlock();
  79                         ll_ints_restore(savedirq);
  80                 }
  81         };
  82 }
  83
  84 #endif