summaryrefslogtreecommitdiff
path: root/include/linux/hardirq.h
blob: 6f657d7f2d04668f7aa360158c582d33f63fcacb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
#ifndef LINUX_HARDIRQ_H
#define LINUX_HARDIRQ_H

#include <linux/preempt.h>
#include <linux/smp_lock.h>
#include <linux/lockdep.h>
#include <asm/hardirq.h>
#include <asm/system.h>

/*
 * We put the hardirq and softirq counter into the preemption
 * counter. The bitmask has the following meaning:
 *
 * - bits 0-7 are the preemption count (max preemption depth: 256)
 * - bits 8-15 are the softirq count (max # of softirqs: 256)
 *
 * The hardirq count can be overridden per architecture, the default is:
 *
 * - bits 16-27 are the hardirq count (max # of hardirqs: 4096)
 * - ( bit 28 is the PREEMPT_ACTIVE flag. )
 *
 * PREEMPT_MASK: 0x000000ff
 * SOFTIRQ_MASK: 0x0000ff00
 * HARDIRQ_MASK: 0x0fff0000
 */
#define PREEMPT_BITS	8
#define SOFTIRQ_BITS	8

#ifndef HARDIRQ_BITS
#define HARDIRQ_BITS	12

#ifndef MAX_HARDIRQS_PER_CPU
#define MAX_HARDIRQS_PER_CPU NR_IRQS
#endif

/*
 * The hardirq mask has to be large enough to have space for potentially
 * all IRQ sources in the system nesting on a single CPU.
 */
#if (1 << HARDIRQ_BITS) < MAX_HARDIRQS_PER_CPU
# error HARDIRQ_BITS is too low!
#endif
#endif

#define PREEMPT_SHIFT	0
#define SOFTIRQ_SHIFT	(PREEMPT_SHIFT + PREEMPT_BITS)
#define HARDIRQ_SHIFT	(SOFTIRQ_SHIFT + SOFTIRQ_BITS)

#define __IRQ_MASK(x)	((1UL << (x))-1)

#define PREEMPT_MASK	(__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT)
#define SOFTIRQ_MASK	(__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
#define HARDIRQ_MASK	(__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)

#define PREEMPT_OFFSET	(1UL << PREEMPT_SHIFT)
#define SOFTIRQ_OFFSET	(1UL << SOFTIRQ_SHIFT)
#define HARDIRQ_OFFSET	(1UL << HARDIRQ_SHIFT)

#if PREEMPT_ACTIVE < (1 << (HARDIRQ_SHIFT + HARDIRQ_BITS))
#error PREEMPT_ACTIVE is too low!
#endif

#define hardirq_count()	(preempt_count() & HARDIRQ_MASK)
#define softirq_count()	(preempt_count() & SOFTIRQ_MASK)
#define irq_count()	(preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK))

/*
 * Are we doing bottom half or hardware interrupt processing?
 * Are we in a softirq context? Interrupt context?
 */
#define in_irq()		(hardirq_count())
#define in_softirq()		(softirq_count())
#define in_interrupt()		(irq_count())

#if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL)
# define in_atomic()	((preempt_count() & ~PREEMPT_ACTIVE) != kernel_locked())
#else
# define in_atomic()	((preempt_count() & ~PREEMPT_ACTIVE) != 0)
#endif

#ifdef CONFIG_PREEMPT
# define preemptible()	(preempt_count() == 0 && !irqs_disabled())
# define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1)
#else
# define preemptible()	0
# define IRQ_EXIT_OFFSET HARDIRQ_OFFSET
#endif

#ifdef CONFIG_SMP
extern void synchronize_irq(unsigned int irq);
#else
# define synchronize_irq(irq)	barrier()
#endif

struct task_struct;

#ifndef CONFIG_VIRT_CPU_ACCOUNTING
static inline void account_system_vtime(struct task_struct *tsk)
{
}
#endif

/*
 * It is safe to do non-atomic ops on ->hardirq_context,
 * because NMI handlers may not preempt and the ops are
 * always balanced, so the interrupted value of ->hardirq_context
 * will always be restored.
 */
extern void irq_enter(void);

/*
 * Exit irq context without processing softirqs:
 */
#define __irq_exit()					\
	do {						\
		trace_hardirq_exit();			\
		account_system_vtime(current);		\
		sub_preempt_count(HARDIRQ_OFFSET);	\
	} while (0)

/*
 * Exit irq context and process softirqs if needed:
 */
extern void irq_exit(void);

#define nmi_enter()		do { lockdep_off(); irq_enter(); } while (0)
#define nmi_exit()		do { __irq_exit(); lockdep_on(); } while (0)

#endif /* LINUX_HARDIRQ_H */