include/linux/hardirq.h

   1 #ifndef LINUX_HARDIRQ_H
   2 #define LINUX_HARDIRQ_H
   3
   4 #include <linux/config.h>
   5 #include <linux/smp_lock.h>
   6 #include <asm/hardirq.h>
   7 #include <asm/system.h>
   8
   9 /*
  10  * We put the hardirq and softirq counter into the preemption
  11  * counter. The bitmask has the following meaning:
  12  *
  13  * - bits 0-7 are the preemption count (max preemption depth: 256)
  14  * - bits 8-15 are the softirq count (max # of softirqs: 256)
  15  *
  16  * The hardirq count can be overridden per architecture, the default is:
  17  *
  18  * - bits 16-27 are the hardirq count (max # of hardirqs: 4096)
  19  * - ( bit 28 is the PREEMPT_ACTIVE flag. )
  20  *
  21  * PREEMPT_MASK: 0x000000ff
  22  * SOFTIRQ_MASK: 0x0000ff00
  23  * HARDIRQ_MASK: 0x0fff0000
  24  */
  25 #define PREEMPT_BITS    8
  26 #define SOFTIRQ_BITS    8
  27
  28 #ifndef HARDIRQ_BITS
  29 #define HARDIRQ_BITS    12
  30 /*
  31  * The hardirq mask has to be large enough to have space for potentially
  32  * all IRQ sources in the system nesting on a single CPU.
  33  */
  34 #if (1 << HARDIRQ_BITS) < NR_IRQS
  35 # error HARDIRQ_BITS is too low!
  36 #endif
  37 #endif
  38
  39 #define PREEMPT_SHIFT   0
  40 #define SOFTIRQ_SHIFT   (PREEMPT_SHIFT + PREEMPT_BITS)
  41 #define HARDIRQ_SHIFT   (SOFTIRQ_SHIFT + SOFTIRQ_BITS)
  42
  43 #define __IRQ_MASK(x)   ((1UL << (x))-1)
  44
  45 #define PREEMPT_MASK    (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT)
  46 #define HARDIRQ_MASK    (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
  47 #define SOFTIRQ_MASK    (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
  48
  49 #define PREEMPT_OFFSET  (1UL << PREEMPT_SHIFT)
  50 #define SOFTIRQ_OFFSET  (1UL << SOFTIRQ_SHIFT)
  51 #define HARDIRQ_OFFSET  (1UL << HARDIRQ_SHIFT)
  52
  53 #define hardirq_count() (preempt_count() & HARDIRQ_MASK)
  54 #define softirq_count() (preempt_count() & SOFTIRQ_MASK)
  55 #define irq_count()     (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK))
  56
  57 /*
  58  * Are we doing bottom half or hardware interrupt processing?
  59  * Are we in a softirq context? Interrupt context?
  60  */
  61 #define in_irq()                (hardirq_count())
  62 #define in_softirq()            (softirq_count())
  63 #define in_interrupt()          (irq_count())
  64
  65 #if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL)
  66 # define in_atomic()    ((preempt_count() & ~PREEMPT_ACTIVE) != kernel_locked())
  67 #else
  68 # define in_atomic()    ((preempt_count() & ~PREEMPT_ACTIVE) != 0)
  69 #endif
  70
  71 #ifdef CONFIG_PREEMPT
  72 # define preemptible()  (preempt_count() == 0 && !irqs_disabled())
  73 # define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1)
  74 #else
  75 # define preemptible()  0
  76 # define IRQ_EXIT_OFFSET HARDIRQ_OFFSET
  77 #endif
  78
  79 #ifdef CONFIG_SMP
  80 extern void synchronize_irq(unsigned int irq);
  81 #else
  82 # define synchronize_irq(irq)   barrier()
  83 #endif
  84
  85 #define nmi_enter()             irq_enter()
  86 #define nmi_exit()              sub_preempt_count(HARDIRQ_OFFSET)
  87
  88 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
  89 static inline void account_user_vtime(struct task_struct *tsk)
  90 {
  91 }
  92
  93 static inline void account_system_vtime(struct task_struct *tsk)
  94 {
  95 }
  96 #endif
  97
  98 #define irq_enter()                                     \
  99         do {                                            \
 100                 account_system_vtime(current);          \
 101                 add_preempt_count(HARDIRQ_OFFSET);      \
 102         } while (0)
 103
 104 extern void irq_exit(void);
 105
 106 #endif /* LINUX_HARDIRQ_H */