include/asm-i386/smplock.h

   1 /*
   2  * <asm/smplock.h>
   3  *
   4  * i386 SMP lock implementation
   5  */
   6 #include <linux/interrupt.h>
   7 #include <linux/spinlock.h>
   8
   9 extern spinlock_t kernel_flag;
  10
  11 /*
  12  * Release global kernel lock and global interrupt lock
  13  */
  14 #define release_kernel_lock(task, cpu) \
  15 do { \
  16         if (task->lock_depth >= 0) \
  17                 spin_unlock(&kernel_flag); \
  18         release_irqlock(cpu); \
  19         __sti(); \
  20 } while (0)
  21
  22 /*
  23  * Re-acquire the kernel lock
  24  */
  25 #define reacquire_kernel_lock(task) \
  26 do { \
  27         if (task->lock_depth >= 0) \
  28                 spin_lock(&kernel_flag); \
  29 } while (0)
  30
  31
  32 /*
  33  * Getting the big kernel lock.
  34  *
  35  * This cannot happen asynchronously,
  36  * so we only need to worry about other
  37  * CPU's.
  38  */
  39 extern __inline__ void lock_kernel(void)
  40 {
  41         __asm__ __volatile__(
  42                 "incl %1\n\t"
  43                 "jne 9f"
  44                 spin_lock_string
  45                 "\n9:"
  46                 :"=m" (__dummy_lock(&kernel_flag)),
  47                  "=m" (current->lock_depth));
  48 }
  49
  50 extern __inline__ void unlock_kernel(void)
  51 {
  52         if (current->lock_depth < 0)
  53                 BUG();
  54         __asm__ __volatile__(
  55                 "decl %1\n\t"
  56                 "jns 9f\n\t"
  57                 spin_unlock_string
  58                 "\n9:"
  59                 :"=m" (__dummy_lock(&kernel_flag)),
  60                  "=m" (current->lock_depth));
  61 }