include/asm-x86_64/smplock.h

   1 /*
   2  * <asm/smplock.h>
   3  */
   4 #include <linux/interrupt.h>
   5 #include <linux/spinlock.h>
   6 #include <linux/sched.h>
   7 #include <asm/current.h>
   8
   9 extern spinlock_cacheline_t kernel_flag_cacheline;
  10 #define kernel_flag kernel_flag_cacheline.lock
  11
  12 #define kernel_locked()         spin_is_locked(&kernel_flag)
  13
  14 /*
  15  * Release global kernel lock and global interrupt lock
  16  */
  17 #define release_kernel_lock(task, cpu) \
  18 do { \
  19         if (task->lock_depth >= 0) \
  20                 spin_unlock(&kernel_flag); \
  21         release_irqlock(cpu); \
  22         __sti(); \
  23 } while (0)
  24
  25 /*
  26  * Re-acquire the kernel lock
  27  */
  28 #define reacquire_kernel_lock(task) \
  29 do { \
  30         if (task->lock_depth >= 0) \
  31                 spin_lock(&kernel_flag); \
  32 } while (0)
  33
  34
  35 /*
  36  * Getting the big kernel lock.
  37  *
  38  * This cannot happen asynchronously,
  39  * so we only need to worry about other
  40  * CPU's.
  41  */
  42 extern __inline__ void lock_kernel(void)
  43 {
  44 #if 1
  45         if (!++current->lock_depth)
  46                 spin_lock(&kernel_flag);
  47 #else
  48         __asm__ __volatile__(
  49                 "incl %1\n\t"
  50                 "jne 9f"
  51                 spin_lock_string
  52                 "\n9:"
  53                 :"=m" (__dummy_lock(&kernel_flag)),
  54                  "=m" (current->lock_depth));
  55 #endif
  56 }
  57
  58 extern __inline__ void unlock_kernel(void)
  59 {
  60         if (current->lock_depth < 0)
  61                 out_of_line_bug();
  62 #if 1
  63         if (--current->lock_depth < 0)
  64                 spin_unlock(&kernel_flag);
  65 #else
  66         __asm__ __volatile__(
  67                 "decl %1\n\t"
  68                 "jns 9f\n\t"
  69                 spin_unlock_string
  70                 "\n9:"
  71                 :"=m" (__dummy_lock(&kernel_flag)),
  72                  "=m" (current->lock_depth));
  73 #endif
  74 }