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 /*
76 * Are we running in atomic context? WARNING: this macro cannot
77 * always detect atomic context; in particular, it cannot know about
78 * held spinlocks in non-preemptible kernels. Thus it should not be
79 * used in the general case to determine whether sleeping is possible.
80 * Do not use in_atomic() in driver code.
81 */
82 #define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != 0)
83
84 #ifdef CONFIG_PREEMPT
85 # define PREEMPT_CHECK_OFFSET 1
86 #else
87 # define PREEMPT_CHECK_OFFSET 0
88 #endif
89
90 /*
91 * Check whether we were atomic before we did preempt_disable():
92 * (used by the scheduler)
93 */
94 #define in_atomic_preempt_off() \
95 ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET)
96
97 #ifdef CONFIG_PREEMPT
98 # define preemptible() (preempt_count() == 0 && !irqs_disabled())
99 # define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1)
100 #else
101 # define preemptible() 0
102 # define IRQ_EXIT_OFFSET HARDIRQ_OFFSET
103 #endif
104
105 #ifdef CONFIG_SMP
106 extern void synchronize_irq(unsigned int irq);
107 #else
108 # define synchronize_irq(irq) barrier()
109 #endif
110
111 struct task_struct;
112
113 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
114 static inline void account_system_vtime(struct task_struct *tsk)
115 {
116 }
117 #endif
118
119 #if defined(CONFIG_PREEMPT_RCU) && defined(CONFIG_NO_HZ)
120 extern void rcu_irq_enter(void);
121 extern void rcu_irq_exit(void);
122 #else
123 # define rcu_irq_enter() do { } while (0)
124 # define rcu_irq_exit() do { } while (0)
125 #endif /* CONFIG_PREEMPT_RCU */
126
127 /*
128 * It is safe to do non-atomic ops on ->hardirq_context,
129 * because NMI handlers may not preempt and the ops are
130 * always balanced, so the interrupted value of ->hardirq_context
131 * will always be restored.
132 */
133 #define __irq_enter() \
134 do { \
135 rcu_irq_enter(); \
136 account_system_vtime(current); \
137 add_preempt_count(HARDIRQ_OFFSET); \
138 trace_hardirq_enter(); \
139 } while (0)
140
141 /*
142 * Enter irq context (on NO_HZ, update jiffies):
143 */
144 extern void irq_enter(void);
145
146 /*
147 * Exit irq context without processing softirqs:
148 */
149 #define __irq_exit() \
150 do { \
151 trace_hardirq_exit(); \
152 account_system_vtime(current); \
153 sub_preempt_count(HARDIRQ_OFFSET); \
154 rcu_irq_exit(); \
155 } while (0)
156
157 /*
158 * Exit irq context and process softirqs if needed:
159 */
160 extern void irq_exit(void);
161
162 #define nmi_enter() do { lockdep_off(); __irq_enter(); } while (0)
163 #define nmi_exit() do { __irq_exit(); lockdep_on(); } while (0)
164
165 #endif /* LINUX_HARDIRQ_H */
166
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