Line data Source code
1 : #ifndef LINUX_HARDIRQ_H
2 : #define LINUX_HARDIRQ_H
3 :
4 : #include <linux/preempt.h>
5 : #ifdef CONFIG_PREEMPT
6 : #include <linux/smp_lock.h>
7 : #endif
8 : #include <linux/lockdep.h>
9 : #include <linux/ftrace_irq.h>
10 : #include <asm/hardirq.h>
11 : #include <asm/system.h>
12 :
13 : /*
14 : * We put the hardirq and softirq counter into the preemption
15 : * counter. The bitmask has the following meaning:
16 : *
17 : * - bits 0-7 are the preemption count (max preemption depth: 256)
18 : * - bits 8-15 are the softirq count (max # of softirqs: 256)
19 : *
20 : * The hardirq count can in theory reach the same as NR_IRQS.
21 : * In reality, the number of nested IRQS is limited to the stack
22 : * size as well. For archs with over 1000 IRQS it is not practical
23 : * to expect that they will all nest. We give a max of 10 bits for
24 : * hardirq nesting. An arch may choose to give less than 10 bits.
25 : * m68k expects it to be 8.
26 : *
27 : * - bits 16-25 are the hardirq count (max # of nested hardirqs: 1024)
28 : * - bit 26 is the NMI_MASK
29 : * - bit 28 is the PREEMPT_ACTIVE flag
30 : *
31 : * PREEMPT_MASK: 0x000000ff
32 : * SOFTIRQ_MASK: 0x0000ff00
33 : * HARDIRQ_MASK: 0x03ff0000
34 : * NMI_MASK: 0x04000000
35 : */
36 : #define PREEMPT_BITS 8
37 : #define SOFTIRQ_BITS 8
38 : #define NMI_BITS 1
39 :
40 : #define MAX_HARDIRQ_BITS 10
41 :
42 : #ifndef HARDIRQ_BITS
43 : # define HARDIRQ_BITS MAX_HARDIRQ_BITS
44 : #endif
45 :
46 : #if HARDIRQ_BITS > MAX_HARDIRQ_BITS
47 : #error HARDIRQ_BITS too high!
48 : #endif
49 :
50 : #define PREEMPT_SHIFT 0
51 : #define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS)
52 : #define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS)
53 : #define NMI_SHIFT (HARDIRQ_SHIFT + HARDIRQ_BITS)
54 :
55 : #define __IRQ_MASK(x) ((1UL << (x))-1)
56 :
57 : #define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT)
58 : #define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
59 : #define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
60 : #define NMI_MASK (__IRQ_MASK(NMI_BITS) << NMI_SHIFT)
61 :
62 : #define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT)
63 : #define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT)
64 : #define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT)
65 : #define NMI_OFFSET (1UL << NMI_SHIFT)
66 :
67 : #ifndef PREEMPT_ACTIVE
68 : #define PREEMPT_ACTIVE_BITS 1
69 : #define PREEMPT_ACTIVE_SHIFT (NMI_SHIFT + NMI_BITS)
70 : #define PREEMPT_ACTIVE (__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT)
71 : #endif
72 :
73 : #if PREEMPT_ACTIVE < (1 << (NMI_SHIFT + NMI_BITS))
74 : #error PREEMPT_ACTIVE is too low!
75 : #endif
76 :
77 : #define hardirq_count() (preempt_count() & HARDIRQ_MASK)
78 : #define softirq_count() (preempt_count() & SOFTIRQ_MASK)
79 : #define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \
80 : | NMI_MASK))
81 :
82 : /*
83 : * Are we doing bottom half or hardware interrupt processing?
84 : * Are we in a softirq context? Interrupt context?
85 : */
86 : #define in_irq() (hardirq_count())
87 : #define in_softirq() (softirq_count())
88 : #define in_interrupt() (irq_count())
89 :
90 : /*
91 : * Are we in NMI context?
92 : */
93 : #define in_nmi() (preempt_count() & NMI_MASK)
94 :
95 : #if defined(CONFIG_PREEMPT)
96 : # define PREEMPT_INATOMIC_BASE kernel_locked()
97 : # define PREEMPT_CHECK_OFFSET 1
98 : #else
99 : # define PREEMPT_INATOMIC_BASE 0
100 : # define PREEMPT_CHECK_OFFSET 0
101 : #endif
102 :
103 : /*
104 : * Are we running in atomic context? WARNING: this macro cannot
105 : * always detect atomic context; in particular, it cannot know about
106 : * held spinlocks in non-preemptible kernels. Thus it should not be
107 : * used in the general case to determine whether sleeping is possible.
108 : * Do not use in_atomic() in driver code.
109 : */
110 : #define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_INATOMIC_BASE)
111 :
112 : /*
113 : * Check whether we were atomic before we did preempt_disable():
114 : * (used by the scheduler, *after* releasing the kernel lock)
115 : */
116 : #define in_atomic_preempt_off() \
117 : ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET)
118 :
119 : #ifdef CONFIG_PREEMPT
120 : # define preemptible() (preempt_count() == 0 && !irqs_disabled())
121 : # define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1)
122 : #else
123 : # define preemptible() 0
124 : # define IRQ_EXIT_OFFSET HARDIRQ_OFFSET
125 : #endif
126 :
127 : #if defined(CONFIG_SMP) || defined(CONFIG_GENERIC_HARDIRQS)
128 : extern void synchronize_irq(unsigned int irq);
129 : #else
130 : # define synchronize_irq(irq) barrier()
131 : #endif
132 :
133 : struct task_struct;
134 :
135 : #ifndef CONFIG_VIRT_CPU_ACCOUNTING
136 : static inline void account_system_vtime(struct task_struct *tsk)
137 : {
138 : }
139 : #endif
140 :
141 : #if defined(CONFIG_NO_HZ)
142 : #if defined(CONFIG_TINY_RCU)
143 : extern void rcu_enter_nohz(void);
144 : extern void rcu_exit_nohz(void);
145 :
146 : static inline void rcu_irq_enter(void)
147 : {
148 : rcu_exit_nohz();
149 : }
150 :
151 : static inline void rcu_irq_exit(void)
152 : {
153 : rcu_enter_nohz();
154 : }
155 :
156 : static inline void rcu_nmi_enter(void)
157 : {
158 : }
159 :
160 : static inline void rcu_nmi_exit(void)
161 : {
162 : }
163 :
164 : #else
165 : extern void rcu_irq_enter(void);
166 : extern void rcu_irq_exit(void);
167 : extern void rcu_nmi_enter(void);
168 : extern void rcu_nmi_exit(void);
169 : #endif
170 : #else
171 : # define rcu_irq_enter() do { } while (0)
172 : # define rcu_irq_exit() do { } while (0)
173 : # define rcu_nmi_enter() do { } while (0)
174 : # define rcu_nmi_exit() do { } while (0)
175 : #endif /* #if defined(CONFIG_NO_HZ) */
176 :
177 : /*
178 : * It is safe to do non-atomic ops on ->hardirq_context,
179 : * because NMI handlers may not preempt and the ops are
180 : * always balanced, so the interrupted value of ->hardirq_context
181 : * will always be restored.
182 : */
183 : #define __irq_enter() \
184 : do { \
185 : account_system_vtime(current); \
186 : add_preempt_count(HARDIRQ_OFFSET); \
187 : trace_hardirq_enter(); \
188 : } while (0)
189 :
190 : /*
191 : * Enter irq context (on NO_HZ, update jiffies):
192 : */
193 : extern void irq_enter(void);
194 :
195 : /*
196 : * Exit irq context without processing softirqs:
197 : */
198 : #define __irq_exit() \
199 : do { \
200 : trace_hardirq_exit(); \
201 : account_system_vtime(current); \
202 : sub_preempt_count(HARDIRQ_OFFSET); \
203 : } while (0)
204 :
205 : /*
206 : * Exit irq context and process softirqs if needed:
207 : */
208 : extern void irq_exit(void);
209 1 :
210 1 : #define nmi_enter() \
211 : do { \
212 : ftrace_nmi_enter(); \
213 : BUG_ON(in_nmi()); \
214 : add_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \
215 : lockdep_off(); \
216 : rcu_nmi_enter(); \
217 : trace_hardirq_enter(); \
218 : } while (0)
219 1 :
220 : #define nmi_exit() \
221 : do { \
222 : trace_hardirq_exit(); \
223 : rcu_nmi_exit(); \
224 1 : lockdep_on(); \
225 : BUG_ON(!in_nmi()); \
226 : sub_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \
227 : ftrace_nmi_exit(); \
228 : } while (0)
229 :
230 : #endif /* LINUX_HARDIRQ_H */
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