LXR linux/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
  80extern 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
  89static inline void account_user_vtime(struct task_struct *tsk)
  90{
  91}
  92
  93static 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
 104extern void irq_exit(void);
 105
 106#endif /* LINUX_HARDIRQ_H */
 107