include/asm-i386/hardirq.h

   1 #ifndef __ASM_HARDIRQ_H
   2 #define __ASM_HARDIRQ_H
   3
   4 #include <linux/threads.h>
   5
   6 extern unsigned int local_irq_count[NR_CPUS];
   7
   8 /*
   9  * Are we in an interrupt context? Either doing bottom half
  10  * or hardware interrupt processing?
  11  */
  12 #define in_interrupt() ({ int __cpu = smp_processor_id(); \
  13         (local_irq_count[__cpu] + local_bh_count[__cpu] != 0); })
  14
  15 #ifndef __SMP__
  16
  17 #define hardirq_trylock(cpu)    (local_irq_count[cpu] == 0)
  18 #define hardirq_endlock(cpu)    do { } while (0)
  19
  20 #define hardirq_enter(cpu)      (local_irq_count[cpu]++)
  21 #define hardirq_exit(cpu)       (local_irq_count[cpu]--)
  22
  23 #define synchronize_irq()       barrier()
  24
  25 #else
  26
  27 #include <asm/atomic.h>
  28
  29 extern unsigned char global_irq_holder;
  30 extern unsigned volatile int global_irq_lock;
  31 extern atomic_t global_irq_count;
  32
  33 static inline void release_irqlock(int cpu)
  34 {
  35         /* if we didn't own the irq lock, just ignore.. */
  36         if (global_irq_holder == (unsigned char) cpu) {
  37                 global_irq_holder = NO_PROC_ID;
  38                 clear_bit(0,&global_irq_lock);
  39         }
  40 }
  41
  42 static inline void hardirq_enter(int cpu)
  43 {
  44         ++local_irq_count[cpu];
  45         atomic_inc(&global_irq_count);
  46 }
  47
  48 static inline void hardirq_exit(int cpu)
  49 {
  50         atomic_dec(&global_irq_count);
  51         --local_irq_count[cpu];
  52 }
  53
  54 static inline int hardirq_trylock(int cpu)
  55 {
  56         return !atomic_read(&global_irq_count) && !test_bit(0,&global_irq_lock);
  57 }
  58
  59 #define hardirq_endlock(cpu)    do { } while (0)
  60
  61 extern void synchronize_irq(void);
  62
  63 #endif /* __SMP__ */
  64
  65 #endif /* __ASM_HARDIRQ_H */