include/asm-ia64/smplock.h

   1 /*
   2  * <asm/smplock.h>
   3  *
   4  * Default SMP lock implementation
   5  */
   6 #include <linux/interrupt.h>
   7 #include <linux/spinlock.h>
   8 #include <linux/sched.h>
   9
  10 #include <asm/current.h>
  11 #include <asm/hardirq.h>
  12
  13 extern spinlock_t kernel_flag;
  14
  15 #ifdef CONFIG_SMP
  16 # define kernel_locked()        spin_is_locked(&kernel_flag)
  17 # define check_irq_holder(cpu)                  \
  18 do {                                            \
  19         if (global_irq_holder == (cpu))         \
  20                 BUG();                          \
  21 } while (0)
  22 #else
  23 # define kernel_locked()        (1)
  24 #endif
  25
  26 /*
  27  * Release global kernel lock and global interrupt lock
  28  */
  29 #define release_kernel_lock(task, cpu)          \
  30 do {                                            \
  31         if (unlikely(task->lock_depth >= 0)) {  \
  32                 spin_unlock(&kernel_flag);      \
  33                 check_irq_holder(cpu);          \
  34         }                                       \
  35 } while (0)
  36
  37 /*
  38  * Re-acquire the kernel lock
  39  */
  40 #define reacquire_kernel_lock(task)             \
  41 do {                                            \
  42         if (unlikely(task->lock_depth >= 0))    \
  43                 spin_lock(&kernel_flag);        \
  44 } while (0)
  45
  46 /*
  47  * Getting the big kernel lock.
  48  *
  49  * This cannot happen asynchronously,
  50  * so we only need to worry about other
  51  * CPU's.
  52  */
  53 static __inline__ void
  54 lock_kernel(void)
  55 {
  56         if (!++current->lock_depth)
  57                 spin_lock(&kernel_flag);
  58 }
  59
  60 static __inline__ void
  61 unlock_kernel(void)
  62 {
  63         if (--current->lock_depth < 0)
  64                 spin_unlock(&kernel_flag);
  65 }