Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1#ifndef LINUX_HARDIRQ_H
2#define LINUX_HARDIRQ_H
3
4#include <linux/preempt.h>
5#include <linux/smp_lock.h>
6#include <linux/lockdep.h>
7#include <asm/hardirq.h>
8#include <asm/system.h>
9
10/*
11 * We put the hardirq and softirq counter into the preemption
12 * counter. The bitmask has the following meaning:
13 *
14 * - bits 0-7 are the preemption count (max preemption depth: 256)
15 * - bits 8-15 are the softirq count (max # of softirqs: 256)
16 *
17 * The hardirq count can be overridden per architecture, the default is:
18 *
19 * - bits 16-27 are the hardirq count (max # of hardirqs: 4096)
20 * - ( bit 28 is the PREEMPT_ACTIVE flag. )
21 *
22 * PREEMPT_MASK: 0x000000ff
23 * SOFTIRQ_MASK: 0x0000ff00
24 * HARDIRQ_MASK: 0x0fff0000
25 */
26#define PREEMPT_BITS 8
27#define SOFTIRQ_BITS 8
28
29#ifndef HARDIRQ_BITS
30#define HARDIRQ_BITS 12
31
32#ifndef MAX_HARDIRQS_PER_CPU
33#define MAX_HARDIRQS_PER_CPU NR_IRQS
34#endif
35
36/*
37 * The hardirq mask has to be large enough to have space for potentially
38 * all IRQ sources in the system nesting on a single CPU.
39 */
40#if (1 << HARDIRQ_BITS) < MAX_HARDIRQS_PER_CPU
41# error HARDIRQ_BITS is too low!
42#endif
43#endif
44
45#define PREEMPT_SHIFT 0
46#define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS)
47#define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS)
48
49#define __IRQ_MASK(x) ((1UL << (x))-1)
50
51#define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT)
52#define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
53#define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
54
55#define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT)
56#define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT)
57#define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT)
58
59#if PREEMPT_ACTIVE < (1 << (HARDIRQ_SHIFT + HARDIRQ_BITS))
60#error PREEMPT_ACTIVE is too low!
61#endif
62
63#define hardirq_count() (preempt_count() & HARDIRQ_MASK)
64#define softirq_count() (preempt_count() & SOFTIRQ_MASK)
65#define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK))
66
67/*
68 * Are we doing bottom half or hardware interrupt processing?
69 * Are we in a softirq context? Interrupt context?
70 */
71#define in_irq() (hardirq_count())
72#define in_softirq() (softirq_count())
73#define in_interrupt() (irq_count())
74
75#define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != 0)
76
77#ifdef CONFIG_PREEMPT
78# define PREEMPT_CHECK_OFFSET 1
79#else
80# define PREEMPT_CHECK_OFFSET 0
81#endif
82
83/*
84 * Check whether we were atomic before we did preempt_disable():
85 * (used by the scheduler)
86 */
87#define in_atomic_preempt_off() \
88 ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET)
89
90#ifdef CONFIG_PREEMPT
91# define preemptible() (preempt_count() == 0 && !irqs_disabled())
92# define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1)
93#else
94# define preemptible() 0
95# define IRQ_EXIT_OFFSET HARDIRQ_OFFSET
96#endif
97
98#ifdef CONFIG_SMP
99extern void synchronize_irq(unsigned int irq);
100#else
101# define synchronize_irq(irq) barrier()
102#endif
103
104struct task_struct;
105
106#ifndef CONFIG_VIRT_CPU_ACCOUNTING
107static inline void account_system_vtime(struct task_struct *tsk)
108{
109}
110#endif
111
112/*
113 * It is safe to do non-atomic ops on ->hardirq_context,
114 * because NMI handlers may not preempt and the ops are
115 * always balanced, so the interrupted value of ->hardirq_context
116 * will always be restored.
117 */
118#define __irq_enter() \
119 do { \
120 account_system_vtime(current); \
121 add_preempt_count(HARDIRQ_OFFSET); \
122 trace_hardirq_enter(); \
123 } while (0)
124
125/*
126 * Enter irq context (on NO_HZ, update jiffies):
127 */
128extern void irq_enter(void);
129
130/*
131 * Exit irq context without processing softirqs:
132 */
133#define __irq_exit() \
134 do { \
135 trace_hardirq_exit(); \
136 account_system_vtime(current); \
137 sub_preempt_count(HARDIRQ_OFFSET); \
138 } while (0)
139
140/*
141 * Exit irq context and process softirqs if needed:
142 */
143extern void irq_exit(void);
144
145#define nmi_enter() do { lockdep_off(); __irq_enter(); } while (0)
146#define nmi_exit() do { __irq_exit(); lockdep_on(); } while (0)
147
148#endif /* LINUX_HARDIRQ_H */