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1 | #ifndef LINUX_HARDIRQ_H |
2 | #define LINUX_HARDIRQ_H |
3 | |
4 | #include <linux/preempt.h> |
5 | #include <linux/lockdep.h> |
6 | #include <linux/ftrace_irq.h> |
7 | #include <linux/vtime.h> |
8 | #include <asm/hardirq.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 in theory reach the same as NR_IRQS. |
18 | * In reality, the number of nested IRQS is limited to the stack |
19 | * size as well. For archs with over 1000 IRQS it is not practical |
20 | * to expect that they will all nest. We give a max of 10 bits for |
21 | * hardirq nesting. An arch may choose to give less than 10 bits. |
22 | * m68k expects it to be 8. |
23 | * |
24 | * - bits 16-25 are the hardirq count (max # of nested hardirqs: 1024) |
25 | * - bit 26 is the NMI_MASK |
26 | * - bit 27 is the PREEMPT_ACTIVE flag |
27 | * |
28 | * PREEMPT_MASK: 0x000000ff |
29 | * SOFTIRQ_MASK: 0x0000ff00 |
30 | * HARDIRQ_MASK: 0x03ff0000 |
31 | * NMI_MASK: 0x04000000 |
32 | */ |
33 | #define PREEMPT_BITS 8 |
34 | #define SOFTIRQ_BITS 8 |
35 | #define NMI_BITS 1 |
36 | |
37 | #define MAX_HARDIRQ_BITS 10 |
38 | |
39 | #ifndef HARDIRQ_BITS |
40 | # define HARDIRQ_BITS MAX_HARDIRQ_BITS |
41 | #endif |
42 | |
43 | #if HARDIRQ_BITS > MAX_HARDIRQ_BITS |
44 | #error HARDIRQ_BITS too high! |
45 | #endif |
46 | |
47 | #define PREEMPT_SHIFT 0 |
48 | #define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS) |
49 | #define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS) |
50 | #define NMI_SHIFT (HARDIRQ_SHIFT + HARDIRQ_BITS) |
51 | |
52 | #define __IRQ_MASK(x) ((1UL << (x))-1) |
53 | |
54 | #define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT) |
55 | #define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT) |
56 | #define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT) |
57 | #define NMI_MASK (__IRQ_MASK(NMI_BITS) << NMI_SHIFT) |
58 | |
59 | #define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT) |
60 | #define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT) |
61 | #define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT) |
62 | #define NMI_OFFSET (1UL << NMI_SHIFT) |
63 | |
64 | #define SOFTIRQ_DISABLE_OFFSET (2 * SOFTIRQ_OFFSET) |
65 | |
66 | #ifndef PREEMPT_ACTIVE |
67 | #define PREEMPT_ACTIVE_BITS 1 |
68 | #define PREEMPT_ACTIVE_SHIFT (NMI_SHIFT + NMI_BITS) |
69 | #define PREEMPT_ACTIVE (__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT) |
70 | #endif |
71 | |
72 | #if PREEMPT_ACTIVE < (1 << (NMI_SHIFT + NMI_BITS)) |
73 | #error PREEMPT_ACTIVE is too low! |
74 | #endif |
75 | |
76 | #define hardirq_count() (preempt_count() & HARDIRQ_MASK) |
77 | #define softirq_count() (preempt_count() & SOFTIRQ_MASK) |
78 | #define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \ |
79 | | NMI_MASK)) |
80 | |
81 | /* |
82 | * Are we doing bottom half or hardware interrupt processing? |
83 | * Are we in a softirq context? Interrupt context? |
84 | * in_softirq - Are we currently processing softirq or have bh disabled? |
85 | * in_serving_softirq - Are we currently processing softirq? |
86 | */ |
87 | #define in_irq() (hardirq_count()) |
88 | #define in_softirq() (softirq_count()) |
89 | #define in_interrupt() (irq_count()) |
90 | #define in_serving_softirq() (softirq_count() & SOFTIRQ_OFFSET) |
91 | |
92 | /* |
93 | * Are we in NMI context? |
94 | */ |
95 | #define in_nmi() (preempt_count() & NMI_MASK) |
96 | |
97 | #if defined(CONFIG_PREEMPT_COUNT) |
98 | # define PREEMPT_CHECK_OFFSET 1 |
99 | #else |
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) != 0) |
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_COUNT |
120 | # define preemptible() (preempt_count() == 0 && !irqs_disabled()) |
121 | #else |
122 | # define preemptible() 0 |
123 | #endif |
124 | |
125 | #if defined(CONFIG_SMP) || defined(CONFIG_GENERIC_HARDIRQS) |
126 | extern void synchronize_irq(unsigned int irq); |
127 | #else |
128 | # define synchronize_irq(irq) barrier() |
129 | #endif |
130 | |
131 | #if defined(CONFIG_TINY_RCU) || defined(CONFIG_TINY_PREEMPT_RCU) |
132 | |
133 | static inline void rcu_nmi_enter(void) |
134 | { |
135 | } |
136 | |
137 | static inline void rcu_nmi_exit(void) |
138 | { |
139 | } |
140 | |
141 | #else |
142 | extern void rcu_nmi_enter(void); |
143 | extern void rcu_nmi_exit(void); |
144 | #endif |
145 | |
146 | /* |
147 | * It is safe to do non-atomic ops on ->hardirq_context, |
148 | * because NMI handlers may not preempt and the ops are |
149 | * always balanced, so the interrupted value of ->hardirq_context |
150 | * will always be restored. |
151 | */ |
152 | #define __irq_enter() \ |
153 | do { \ |
154 | account_irq_enter_time(current); \ |
155 | add_preempt_count(HARDIRQ_OFFSET); \ |
156 | trace_hardirq_enter(); \ |
157 | } while (0) |
158 | |
159 | /* |
160 | * Enter irq context (on NO_HZ, update jiffies): |
161 | */ |
162 | extern void irq_enter(void); |
163 | |
164 | /* |
165 | * Exit irq context without processing softirqs: |
166 | */ |
167 | #define __irq_exit() \ |
168 | do { \ |
169 | trace_hardirq_exit(); \ |
170 | account_irq_exit_time(current); \ |
171 | sub_preempt_count(HARDIRQ_OFFSET); \ |
172 | } while (0) |
173 | |
174 | /* |
175 | * Exit irq context and process softirqs if needed: |
176 | */ |
177 | extern void irq_exit(void); |
178 | |
179 | #define nmi_enter() \ |
180 | do { \ |
181 | lockdep_off(); \ |
182 | ftrace_nmi_enter(); \ |
183 | BUG_ON(in_nmi()); \ |
184 | add_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \ |
185 | rcu_nmi_enter(); \ |
186 | trace_hardirq_enter(); \ |
187 | } while (0) |
188 | |
189 | #define nmi_exit() \ |
190 | do { \ |
191 | trace_hardirq_exit(); \ |
192 | rcu_nmi_exit(); \ |
193 | BUG_ON(!in_nmi()); \ |
194 | sub_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \ |
195 | ftrace_nmi_exit(); \ |
196 | lockdep_on(); \ |
197 | } while (0) |
198 | |
199 | #endif /* LINUX_HARDIRQ_H */ |
200 |
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