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[J-linux.git] / include / linux / context_tracking.h
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
14 extern void ct_cpu_track_user(int cpu);
15
16 /* Called with interrupts disabled.  */
17 extern void __ct_user_enter(enum ctx_state state);
18 extern void __ct_user_exit(enum ctx_state state);
19
20 extern void ct_user_enter(enum ctx_state state);
21 extern void ct_user_exit(enum ctx_state state);
22
23 extern void user_enter_callable(void);
24 extern void user_exit_callable(void);
25
26 static inline void user_enter(void)
27 {
28         if (context_tracking_enabled())
29                 ct_user_enter(CT_STATE_USER);
30
31 }
32 static 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.  */
39 static __always_inline void user_enter_irqoff(void)
40 {
41         if (context_tracking_enabled())
42                 __ct_user_enter(CT_STATE_USER);
43
44 }
45 static __always_inline void user_exit_irqoff(void)
46 {
47         if (context_tracking_enabled())
48                 __ct_user_exit(CT_STATE_USER);
49 }
50
51 static 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
66 static 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
75 static __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
83 static __always_inline void context_tracking_guest_exit(void)
84 {
85         if (context_tracking_enabled())
86                 __ct_user_exit(CT_STATE_GUEST);
87 }
88
89 #define CT_WARN_ON(cond) WARN_ON(context_tracking_enabled() && (cond))
90
91 #else
92 static inline void user_enter(void) { }
93 static inline void user_exit(void) { }
94 static inline void user_enter_irqoff(void) { }
95 static inline void user_exit_irqoff(void) { }
96 static inline int exception_enter(void) { return 0; }
97 static inline void exception_exit(enum ctx_state prev_ctx) { }
98 static inline int ct_state(void) { return -1; }
99 static inline int __ct_state(void) { return -1; }
100 static __always_inline bool context_tracking_guest_enter(void) { return false; }
101 static __always_inline void context_tracking_guest_exit(void) { }
102 #define CT_WARN_ON(cond) do { } while (0)
103 #endif /* !CONFIG_CONTEXT_TRACKING_USER */
104
105 #ifdef CONFIG_CONTEXT_TRACKING_USER_FORCE
106 extern void context_tracking_init(void);
107 #else
108 static inline void context_tracking_init(void) { }
109 #endif /* CONFIG_CONTEXT_TRACKING_USER_FORCE */
110
111 #ifdef CONFIG_CONTEXT_TRACKING_IDLE
112 extern void ct_idle_enter(void);
113 extern void ct_idle_exit(void);
114
115 /*
116  * Is RCU watching the current CPU (IOW, it is not in an extended quiescent state)?
117  *
118  * Note that this returns the actual boolean data (watching / not watching),
119  * whereas ct_rcu_watching() returns the RCU_WATCHING subvariable of
120  * context_tracking.state.
121  *
122  * No ordering, as we are sampling CPU-local information.
123  */
124 static __always_inline bool rcu_is_watching_curr_cpu(void)
125 {
126         return raw_atomic_read(this_cpu_ptr(&context_tracking.state)) & CT_RCU_WATCHING;
127 }
128
129 /*
130  * Increment the current CPU's context_tracking structure's ->state field
131  * with ordering.  Return the new value.
132  */
133 static __always_inline unsigned long ct_state_inc(int incby)
134 {
135         return raw_atomic_add_return(incby, this_cpu_ptr(&context_tracking.state));
136 }
137
138 static __always_inline bool warn_rcu_enter(void)
139 {
140         bool ret = false;
141
142         /*
143          * Horrible hack to shut up recursive RCU isn't watching fail since
144          * lots of the actual reporting also relies on RCU.
145          */
146         preempt_disable_notrace();
147         if (!rcu_is_watching_curr_cpu()) {
148                 ret = true;
149                 ct_state_inc(CT_RCU_WATCHING);
150         }
151
152         return ret;
153 }
154
155 static __always_inline void warn_rcu_exit(bool rcu)
156 {
157         if (rcu)
158                 ct_state_inc(CT_RCU_WATCHING);
159         preempt_enable_notrace();
160 }
161
162 #else
163 static inline void ct_idle_enter(void) { }
164 static inline void ct_idle_exit(void) { }
165
166 static __always_inline bool warn_rcu_enter(void) { return false; }
167 static __always_inline void warn_rcu_exit(bool rcu) { }
168 #endif /* !CONFIG_CONTEXT_TRACKING_IDLE */
169
170 #endif
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