tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
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 <linux/ftrace_irq.h>
8#include <asm/hardirq.h>
9#include <asm/system.h>
10
11/*
12 * We put the hardirq and softirq counter into the preemption
13 * counter. The bitmask has the following meaning:
14 *
15 * - bits 0-7 are the preemption count (max preemption depth: 256)
16 * - bits 8-15 are the softirq count (max # of softirqs: 256)
17 *
18 * The hardirq count can be overridden per architecture, the default is:
19 *
20 * - bits 16-27 are the hardirq count (max # of hardirqs: 4096)
21 * - ( bit 28 is the PREEMPT_ACTIVE flag. )
22 *
23 * PREEMPT_MASK: 0x000000ff
24 * SOFTIRQ_MASK: 0x0000ff00
25 * HARDIRQ_MASK: 0x0fff0000
26 */
27#define PREEMPT_BITS 8
28#define SOFTIRQ_BITS 8
29
30#ifndef HARDIRQ_BITS
31#define HARDIRQ_BITS 12
32
33#ifndef MAX_HARDIRQS_PER_CPU
34#define MAX_HARDIRQS_PER_CPU NR_IRQS
35#endif
36
37/*
38 * The hardirq mask has to be large enough to have space for potentially
39 * all IRQ sources in the system nesting on a single CPU.
40 */
41#if (1 << HARDIRQ_BITS) < MAX_HARDIRQS_PER_CPU
42# error HARDIRQ_BITS is too low!
43#endif
44#endif
45
46#define PREEMPT_SHIFT 0
47#define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS)
48#define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS)
49
50#define __IRQ_MASK(x) ((1UL << (x))-1)
51
52#define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT)
53#define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
54#define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
55
56#define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT)
57#define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT)
58#define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT)
59
60#if PREEMPT_ACTIVE < (1 << (HARDIRQ_SHIFT + HARDIRQ_BITS))
61#error PREEMPT_ACTIVE is too low!
62#endif
63
64#define hardirq_count() (preempt_count() & HARDIRQ_MASK)
65#define softirq_count() (preempt_count() & SOFTIRQ_MASK)
66#define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK))
67
68/*
69 * Are we doing bottom half or hardware interrupt processing?
70 * Are we in a softirq context? Interrupt context?
71 */
72#define in_irq() (hardirq_count())
73#define in_softirq() (softirq_count())
74#define in_interrupt() (irq_count())
75
76#if defined(CONFIG_PREEMPT)
77# define PREEMPT_INATOMIC_BASE kernel_locked()
78# define PREEMPT_CHECK_OFFSET 1
79#else
80# define PREEMPT_INATOMIC_BASE 0
81# define PREEMPT_CHECK_OFFSET 0
82#endif
83
84/*
85 * Are we running in atomic context? WARNING: this macro cannot
86 * always detect atomic context; in particular, it cannot know about
87 * held spinlocks in non-preemptible kernels. Thus it should not be
88 * used in the general case to determine whether sleeping is possible.
89 * Do not use in_atomic() in driver code.
90 */
91#define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_INATOMIC_BASE)
92
93/*
94 * Check whether we were atomic before we did preempt_disable():
95 * (used by the scheduler, *after* releasing the kernel lock)
96 */
97#define in_atomic_preempt_off() \
98 ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET)
99
100#ifdef CONFIG_PREEMPT
101# define preemptible() (preempt_count() == 0 && !irqs_disabled())
102# define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1)
103#else
104# define preemptible() 0
105# define IRQ_EXIT_OFFSET HARDIRQ_OFFSET
106#endif
107
108#ifdef CONFIG_SMP
109extern void synchronize_irq(unsigned int irq);
110#else
111# define synchronize_irq(irq) barrier()
112#endif
113
114struct task_struct;
115
116#ifndef CONFIG_VIRT_CPU_ACCOUNTING
117static inline void account_system_vtime(struct task_struct *tsk)
118{
119}
120#endif
121
122#if defined(CONFIG_NO_HZ) && !defined(CONFIG_CLASSIC_RCU)
123extern void rcu_irq_enter(void);
124extern void rcu_irq_exit(void);
125extern void rcu_nmi_enter(void);
126extern void rcu_nmi_exit(void);
127#else
128# define rcu_irq_enter() do { } while (0)
129# define rcu_irq_exit() do { } while (0)
130# define rcu_nmi_enter() do { } while (0)
131# define rcu_nmi_exit() do { } while (0)
132#endif /* #if defined(CONFIG_NO_HZ) && !defined(CONFIG_CLASSIC_RCU) */
133
134/*
135 * It is safe to do non-atomic ops on ->hardirq_context,
136 * because NMI handlers may not preempt and the ops are
137 * always balanced, so the interrupted value of ->hardirq_context
138 * will always be restored.
139 */
140#define __irq_enter() \
141 do { \
142 account_system_vtime(current); \
143 add_preempt_count(HARDIRQ_OFFSET); \
144 trace_hardirq_enter(); \
145 } while (0)
146
147/*
148 * Enter irq context (on NO_HZ, update jiffies):
149 */
150extern void irq_enter(void);
151
152/*
153 * Exit irq context without processing softirqs:
154 */
155#define __irq_exit() \
156 do { \
157 trace_hardirq_exit(); \
158 account_system_vtime(current); \
159 sub_preempt_count(HARDIRQ_OFFSET); \
160 } while (0)
161
162/*
163 * Exit irq context and process softirqs if needed:
164 */
165extern void irq_exit(void);
166
167#define nmi_enter() \
168 do { \
169 ftrace_nmi_enter(); \
170 lockdep_off(); \
171 rcu_nmi_enter(); \
172 __irq_enter(); \
173 } while (0)
174
175#define nmi_exit() \
176 do { \
177 __irq_exit(); \
178 rcu_nmi_exit(); \
179 lockdep_on(); \
180 ftrace_nmi_exit(); \
181 } while (0)
182
183#endif /* LINUX_HARDIRQ_H */