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 
user_enter(void)26 static inline void user_enter(void)
27 {
28 	if (context_tracking_enabled())
29 		ct_user_enter(CONTEXT_USER);
30 
31 }
user_exit(void)32 static inline void user_exit(void)
33 {
34 	if (context_tracking_enabled())
35 		ct_user_exit(CONTEXT_USER);
36 }
37 
38 /* Called with interrupts disabled.  */
user_enter_irqoff(void)39 static __always_inline void user_enter_irqoff(void)
40 {
41 	if (context_tracking_enabled())
42 		__ct_user_enter(CONTEXT_USER);
43 
44 }
user_exit_irqoff(void)45 static __always_inline void user_exit_irqoff(void)
46 {
47 	if (context_tracking_enabled())
48 		__ct_user_exit(CONTEXT_USER);
49 }
50 
exception_enter(void)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 != CONTEXT_KERNEL)
61 		ct_user_exit(prev_ctx);
62 
63 	return prev_ctx;
64 }
65 
exception_exit(enum ctx_state prev_ctx)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 != CONTEXT_KERNEL)
71 			ct_user_enter(prev_ctx);
72 	}
73 }
74 
context_tracking_guest_enter(void)75 static __always_inline bool context_tracking_guest_enter(void)
76 {
77 	if (context_tracking_enabled())
78 		__ct_user_enter(CONTEXT_GUEST);
79 
80 	return context_tracking_enabled_this_cpu();
81 }
82 
context_tracking_guest_exit(void)83 static __always_inline void context_tracking_guest_exit(void)
84 {
85 	if (context_tracking_enabled())
86 		__ct_user_exit(CONTEXT_GUEST);
87 }
88 
89 #define CT_WARN_ON(cond) WARN_ON(context_tracking_enabled() && (cond))
90 
91 #else
user_enter(void)92 static inline void user_enter(void) { }
user_exit(void)93 static inline void user_exit(void) { }
user_enter_irqoff(void)94 static inline void user_enter_irqoff(void) { }
user_exit_irqoff(void)95 static inline void user_exit_irqoff(void) { }
exception_enter(void)96 static inline int exception_enter(void) { return 0; }
exception_exit(enum ctx_state prev_ctx)97 static inline void exception_exit(enum ctx_state prev_ctx) { }
ct_state(void)98 static inline int ct_state(void) { return -1; }
__ct_state(void)99 static inline int __ct_state(void) { return -1; }
context_tracking_guest_enter(void)100 static __always_inline bool context_tracking_guest_enter(void) { return false; }
context_tracking_guest_exit(void)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
context_tracking_init(void)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 the current CPU in an extended quiescent state?
117  *
118  * No ordering, as we are sampling CPU-local information.
119  */
rcu_dynticks_curr_cpu_in_eqs(void)120 static __always_inline bool rcu_dynticks_curr_cpu_in_eqs(void)
121 {
122 	return !(raw_atomic_read(this_cpu_ptr(&context_tracking.state)) & RCU_DYNTICKS_IDX);
123 }
124 
125 /*
126  * Increment the current CPU's context_tracking structure's ->state field
127  * with ordering.  Return the new value.
128  */
ct_state_inc(int incby)129 static __always_inline unsigned long ct_state_inc(int incby)
130 {
131 	return raw_atomic_add_return(incby, this_cpu_ptr(&context_tracking.state));
132 }
133 
warn_rcu_enter(void)134 static __always_inline bool warn_rcu_enter(void)
135 {
136 	bool ret = false;
137 
138 	/*
139 	 * Horrible hack to shut up recursive RCU isn't watching fail since
140 	 * lots of the actual reporting also relies on RCU.
141 	 */
142 	preempt_disable_notrace();
143 	if (rcu_dynticks_curr_cpu_in_eqs()) {
144 		ret = true;
145 		ct_state_inc(RCU_DYNTICKS_IDX);
146 	}
147 
148 	return ret;
149 }
150 
warn_rcu_exit(bool rcu)151 static __always_inline void warn_rcu_exit(bool rcu)
152 {
153 	if (rcu)
154 		ct_state_inc(RCU_DYNTICKS_IDX);
155 	preempt_enable_notrace();
156 }
157 
158 #else
ct_idle_enter(void)159 static inline void ct_idle_enter(void) { }
ct_idle_exit(void)160 static inline void ct_idle_exit(void) { }
161 
warn_rcu_enter(void)162 static __always_inline bool warn_rcu_enter(void) { return false; }
warn_rcu_exit(bool rcu)163 static __always_inline void warn_rcu_exit(bool rcu) { }
164 #endif /* !CONFIG_CONTEXT_TRACKING_IDLE */
165 
166 #endif
167