1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef LINUX_HARDIRQ_H
3#define LINUX_HARDIRQ_H
4
5#include <linux/context_tracking_state.h>
6#include <linux/preempt.h>
7#include <linux/lockdep.h>
8#include <linux/ftrace_irq.h>
9#include <linux/sched.h>
10#include <linux/vtime.h>
11#include <asm/hardirq.h>
12
13extern void synchronize_irq(unsigned int irq);
14extern bool synchronize_hardirq(unsigned int irq);
15
16#ifdef CONFIG_NO_HZ_FULL
17void __rcu_irq_enter_check_tick(void);
18#else
19static inline void __rcu_irq_enter_check_tick(void) { }
20#endif
21
22static __always_inline void rcu_irq_enter_check_tick(void)
23{
24	if (context_tracking_enabled())
25		__rcu_irq_enter_check_tick();
26}
27
28/*
29 * It is safe to do non-atomic ops on ->hardirq_context,
30 * because NMI handlers may not preempt and the ops are
31 * always balanced, so the interrupted value of ->hardirq_context
32 * will always be restored.
33 */
34#define __irq_enter()					\
35	do {						\
36		preempt_count_add(HARDIRQ_OFFSET);	\
37		lockdep_hardirq_enter();		\
38		account_hardirq_enter(current);		\
39	} while (0)
40
41/*
42 * Like __irq_enter() without time accounting for fast
43 * interrupts, e.g. reschedule IPI where time accounting
44 * is more expensive than the actual interrupt.
45 */
46#define __irq_enter_raw()				\
47	do {						\
48		preempt_count_add(HARDIRQ_OFFSET);	\
49		lockdep_hardirq_enter();		\
50	} while (0)
51
52/*
53 * Enter irq context (on NO_HZ, update jiffies):
54 */
55void irq_enter(void);
56/*
57 * Like irq_enter(), but RCU is already watching.
58 */
59void irq_enter_rcu(void);
60
61/*
62 * Exit irq context without processing softirqs:
63 */
64#define __irq_exit()					\
65	do {						\
66		account_hardirq_exit(current);		\
67		lockdep_hardirq_exit();			\
68		preempt_count_sub(HARDIRQ_OFFSET);	\
69	} while (0)
70
71/*
72 * Like __irq_exit() without time accounting
73 */
74#define __irq_exit_raw()				\
75	do {						\
76		lockdep_hardirq_exit();			\
77		preempt_count_sub(HARDIRQ_OFFSET);	\
78	} while (0)
79
80/*
81 * Exit irq context and process softirqs if needed:
82 */
83void irq_exit(void);
84
85/*
86 * Like irq_exit(), but return with RCU watching.
87 */
88void irq_exit_rcu(void);
89
90#ifndef arch_nmi_enter
91#define arch_nmi_enter()	do { } while (0)
92#define arch_nmi_exit()		do { } while (0)
93#endif
94
95/*
96 * NMI vs Tracing
97 * --------------
98 *
99 * We must not land in a tracer until (or after) we've changed preempt_count
100 * such that in_nmi() becomes true. To that effect all NMI C entry points must
101 * be marked 'notrace' and call nmi_enter() as soon as possible.
102 */
103
104/*
105 * nmi_enter() can nest up to 15 times; see NMI_BITS.
106 */
107#define __nmi_enter()						\
108	do {							\
109		lockdep_off();					\
110		arch_nmi_enter();				\
111		BUG_ON(in_nmi() == NMI_MASK);			\
112		__preempt_count_add(NMI_OFFSET + HARDIRQ_OFFSET);	\
113	} while (0)
114
115#define nmi_enter()						\
116	do {							\
117		__nmi_enter();					\
118		lockdep_hardirq_enter();			\
119		ct_nmi_enter();				\
120		instrumentation_begin();			\
121		ftrace_nmi_enter();				\
122		instrumentation_end();				\
123	} while (0)
124
125#define __nmi_exit()						\
126	do {							\
127		BUG_ON(!in_nmi());				\
128		__preempt_count_sub(NMI_OFFSET + HARDIRQ_OFFSET);	\
129		arch_nmi_exit();				\
130		lockdep_on();					\
131	} while (0)
132
133#define nmi_exit()						\
134	do {							\
135		instrumentation_begin();			\
136		ftrace_nmi_exit();				\
137		instrumentation_end();				\
138		ct_nmi_exit();					\
139		lockdep_hardirq_exit();				\
140		__nmi_exit();					\
141	} while (0)
142
143#endif /* LINUX_HARDIRQ_H */
144