1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_CONTEXT_TRACKING_H
3#define _LINUX_CONTEXT_TRACKING_H
4
5#include <linux/sched.h>
6#include <linux/vtime.h>
7#include <linux/context_tracking_state.h>
8#include <linux/instrumentation.h>
9
10#include <asm/ptrace.h>
11
12
13#ifdef CONFIG_CONTEXT_TRACKING_USER
14extern void ct_cpu_track_user(int cpu);
15
16/* Called with interrupts disabled. */
17extern void __ct_user_enter(enum ctx_state state);
18extern void __ct_user_exit(enum ctx_state state);
19
20extern void ct_user_enter(enum ctx_state state);
21extern void ct_user_exit(enum ctx_state state);
22
23extern void user_enter_callable(void);
24extern void user_exit_callable(void);
25
26static inline void user_enter(void)
27{
28 if (context_tracking_enabled())
29 ct_user_enter(CT_STATE_USER);
30
31}
32static inline void user_exit(void)
33{
34 if (context_tracking_enabled())
35 ct_user_exit(CT_STATE_USER);
36}
37
38/* Called with interrupts disabled. */
39static __always_inline void user_enter_irqoff(void)
40{
41 if (context_tracking_enabled())
42 __ct_user_enter(CT_STATE_USER);
43
44}
45static __always_inline void user_exit_irqoff(void)
46{
47 if (context_tracking_enabled())
48 __ct_user_exit(CT_STATE_USER);
49}
50
51static inline enum ctx_state exception_enter(void)
52{
53 enum ctx_state prev_ctx;
54
55 if (IS_ENABLED(CONFIG_HAVE_CONTEXT_TRACKING_USER_OFFSTACK) ||
56 !context_tracking_enabled())
57 return 0;
58
59 prev_ctx = __ct_state();
60 if (prev_ctx != CT_STATE_KERNEL)
61 ct_user_exit(prev_ctx);
62
63 return prev_ctx;
64}
65
66static inline void exception_exit(enum ctx_state prev_ctx)
67{
68 if (!IS_ENABLED(CONFIG_HAVE_CONTEXT_TRACKING_USER_OFFSTACK) &&
69 context_tracking_enabled()) {
70 if (prev_ctx != CT_STATE_KERNEL)
71 ct_user_enter(prev_ctx);
72 }
73}
74
75static __always_inline bool context_tracking_guest_enter(void)
76{
77 if (context_tracking_enabled())
78 __ct_user_enter(CT_STATE_GUEST);
79
80 return context_tracking_enabled_this_cpu();
81}
82
83static __always_inline bool context_tracking_guest_exit(void)
84{
85 if (context_tracking_enabled())
86 __ct_user_exit(CT_STATE_GUEST);
87
88 return context_tracking_enabled_this_cpu();
89}
90
91#define CT_WARN_ON(cond) WARN_ON(context_tracking_enabled() && (cond))
92
93#else
94static inline void user_enter(void) { }
95static inline void user_exit(void) { }
96static inline void user_enter_irqoff(void) { }
97static inline void user_exit_irqoff(void) { }
98static inline int exception_enter(void) { return 0; }
99static inline void exception_exit(enum ctx_state prev_ctx) { }
100static inline int ct_state(void) { return -1; }
101static inline int __ct_state(void) { return -1; }
102static __always_inline bool context_tracking_guest_enter(void) { return false; }
103static __always_inline bool context_tracking_guest_exit(void) { return false; }
104#define CT_WARN_ON(cond) do { } while (0)
105#endif /* !CONFIG_CONTEXT_TRACKING_USER */
106
107#ifdef CONFIG_CONTEXT_TRACKING_USER_FORCE
108extern void context_tracking_init(void);
109#else
110static inline void context_tracking_init(void) { }
111#endif /* CONFIG_CONTEXT_TRACKING_USER_FORCE */
112
113#ifdef CONFIG_CONTEXT_TRACKING_IDLE
114extern void ct_idle_enter(void);
115extern void ct_idle_exit(void);
116
117/*
118 * Is RCU watching the current CPU (IOW, it is not in an extended quiescent state)?
119 *
120 * Note that this returns the actual boolean data (watching / not watching),
121 * whereas ct_rcu_watching() returns the RCU_WATCHING subvariable of
122 * context_tracking.state.
123 *
124 * No ordering, as we are sampling CPU-local information.
125 */
126static __always_inline bool rcu_is_watching_curr_cpu(void)
127{
128 return raw_atomic_read(this_cpu_ptr(&context_tracking.state)) & CT_RCU_WATCHING;
129}
130
131/*
132 * Increment the current CPU's context_tracking structure's ->state field
133 * with ordering. Return the new value.
134 */
135static __always_inline unsigned long ct_state_inc(int incby)
136{
137 return raw_atomic_add_return(i: incby, this_cpu_ptr(&context_tracking.state));
138}
139
140static __always_inline bool warn_rcu_enter(void)
141{
142 bool ret = false;
143
144 /*
145 * Horrible hack to shut up recursive RCU isn't watching fail since
146 * lots of the actual reporting also relies on RCU.
147 */
148 preempt_disable_notrace();
149 if (!rcu_is_watching_curr_cpu()) {
150 ret = true;
151 ct_state_inc(CT_RCU_WATCHING);
152 }
153
154 return ret;
155}
156
157static __always_inline void warn_rcu_exit(bool rcu)
158{
159 if (rcu)
160 ct_state_inc(CT_RCU_WATCHING);
161 preempt_enable_notrace();
162}
163
164#else
165static inline void ct_idle_enter(void) { }
166static inline void ct_idle_exit(void) { }
167
168static __always_inline bool warn_rcu_enter(void) { return false; }
169static __always_inline void warn_rcu_exit(bool rcu) { }
170#endif /* !CONFIG_CONTEXT_TRACKING_IDLE */
171
172#endif
173

source code of linux/include/linux/context_tracking.h