hardirq.h revision 62c4f0a2d5a188f73a94f2cb8ea0dba3e7cf0a7f 
1#ifndef LINUX_HARDIRQ_H
2#define LINUX_HARDIRQ_H
3
4#include <linux/preempt.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 SOFTIRQ_MASK	(__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
47#define HARDIRQ_MASK	(__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_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#if PREEMPT_ACTIVE < (1 << (HARDIRQ_SHIFT + HARDIRQ_BITS))
54#error PREEMPT_ACTIVE is too low!
55#endif
56
57#define hardirq_count()	(preempt_count() & HARDIRQ_MASK)
58#define softirq_count()	(preempt_count() & SOFTIRQ_MASK)
59#define irq_count()	(preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK))
60
61/*
62 * Are we doing bottom half or hardware interrupt processing?
63 * Are we in a softirq context? Interrupt context?
64 */
65#define in_irq()		(hardirq_count())
66#define in_softirq()		(softirq_count())
67#define in_interrupt()		(irq_count())
68
69#if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL)
70# define in_atomic()	((preempt_count() & ~PREEMPT_ACTIVE) != kernel_locked())
71#else
72# define in_atomic()	((preempt_count() & ~PREEMPT_ACTIVE) != 0)
73#endif
74
75#ifdef CONFIG_PREEMPT
76# define preemptible()	(preempt_count() == 0 && !irqs_disabled())
77# define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1)
78#else
79# define preemptible()	0
80# define IRQ_EXIT_OFFSET HARDIRQ_OFFSET
81#endif
82
83#ifdef CONFIG_SMP
84extern void synchronize_irq(unsigned int irq);
85#else
86# define synchronize_irq(irq)	barrier()
87#endif
88
89#define nmi_enter()		irq_enter()
90#define nmi_exit()		sub_preempt_count(HARDIRQ_OFFSET)
91
92struct task_struct;
93
94#ifndef CONFIG_VIRT_CPU_ACCOUNTING
95static inline void account_system_vtime(struct task_struct *tsk)
96{
97}
98#endif
99
100#define irq_enter()					\
101	do {						\
102		account_system_vtime(current);		\
103		add_preempt_count(HARDIRQ_OFFSET);	\
104	} while (0)
105
106extern void irq_exit(void);
107
108#endif /* LINUX_HARDIRQ_H */
109