include/asm-ppc/smplock.h

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