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 <asm/ptrace.h>
9 
10 
11 #ifdef CONFIG_CONTEXT_TRACKING
12 extern void context_tracking_cpu_set(int cpu);
13 
14 /* Called with interrupts disabled.  */
15 extern void __context_tracking_enter(enum ctx_state state);
16 extern void __context_tracking_exit(enum ctx_state state);
17 
18 extern void context_tracking_enter(enum ctx_state state);
19 extern void context_tracking_exit(enum ctx_state state);
20 extern void context_tracking_user_enter(void);
21 extern void context_tracking_user_exit(void);
22 
user_enter(void)23 static inline void user_enter(void)
24 {
25 	if (context_tracking_is_enabled())
26 		context_tracking_enter(CONTEXT_USER);
27 
28 }
user_exit(void)29 static inline void user_exit(void)
30 {
31 	if (context_tracking_is_enabled())
32 		context_tracking_exit(CONTEXT_USER);
33 }
34 
35 /* Called with interrupts disabled.  */
user_enter_irqoff(void)36 static inline void user_enter_irqoff(void)
37 {
38 	if (context_tracking_is_enabled())
39 		__context_tracking_enter(CONTEXT_USER);
40 
41 }
user_exit_irqoff(void)42 static inline void user_exit_irqoff(void)
43 {
44 	if (context_tracking_is_enabled())
45 		__context_tracking_exit(CONTEXT_USER);
46 }
47 
exception_enter(void)48 static inline enum ctx_state exception_enter(void)
49 {
50 	enum ctx_state prev_ctx;
51 
52 	if (!context_tracking_is_enabled())
53 		return 0;
54 
55 	prev_ctx = this_cpu_read(context_tracking.state);
56 	if (prev_ctx != CONTEXT_KERNEL)
57 		context_tracking_exit(prev_ctx);
58 
59 	return prev_ctx;
60 }
61 
exception_exit(enum ctx_state prev_ctx)62 static inline void exception_exit(enum ctx_state prev_ctx)
63 {
64 	if (context_tracking_is_enabled()) {
65 		if (prev_ctx != CONTEXT_KERNEL)
66 			context_tracking_enter(prev_ctx);
67 	}
68 }
69 
70 
71 /**
72  * ct_state() - return the current context tracking state if known
73  *
74  * Returns the current cpu's context tracking state if context tracking
75  * is enabled.  If context tracking is disabled, returns
76  * CONTEXT_DISABLED.  This should be used primarily for debugging.
77  */
ct_state(void)78 static inline enum ctx_state ct_state(void)
79 {
80 	return context_tracking_is_enabled() ?
81 		this_cpu_read(context_tracking.state) : CONTEXT_DISABLED;
82 }
83 #else
user_enter(void)84 static inline void user_enter(void) { }
user_exit(void)85 static inline void user_exit(void) { }
user_enter_irqoff(void)86 static inline void user_enter_irqoff(void) { }
user_exit_irqoff(void)87 static inline void user_exit_irqoff(void) { }
exception_enter(void)88 static inline enum ctx_state exception_enter(void) { return 0; }
exception_exit(enum ctx_state prev_ctx)89 static inline void exception_exit(enum ctx_state prev_ctx) { }
ct_state(void)90 static inline enum ctx_state ct_state(void) { return CONTEXT_DISABLED; }
91 #endif /* !CONFIG_CONTEXT_TRACKING */
92 
93 #define CT_WARN_ON(cond) WARN_ON(context_tracking_is_enabled() && (cond))
94 
95 #ifdef CONFIG_CONTEXT_TRACKING_FORCE
96 extern void context_tracking_init(void);
97 #else
context_tracking_init(void)98 static inline void context_tracking_init(void) { }
99 #endif /* CONFIG_CONTEXT_TRACKING_FORCE */
100 
101 
102 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
103 /* must be called with irqs disabled */
guest_enter_irqoff(void)104 static inline void guest_enter_irqoff(void)
105 {
106 	if (vtime_accounting_cpu_enabled())
107 		vtime_guest_enter(current);
108 	else
109 		current->flags |= PF_VCPU;
110 
111 	if (context_tracking_is_enabled())
112 		__context_tracking_enter(CONTEXT_GUEST);
113 
114 	/* KVM does not hold any references to rcu protected data when it
115 	 * switches CPU into a guest mode. In fact switching to a guest mode
116 	 * is very similar to exiting to userspace from rcu point of view. In
117 	 * addition CPU may stay in a guest mode for quite a long time (up to
118 	 * one time slice). Lets treat guest mode as quiescent state, just like
119 	 * we do with user-mode execution.
120 	 */
121 	if (!context_tracking_cpu_is_enabled())
122 		rcu_virt_note_context_switch(smp_processor_id());
123 }
124 
guest_exit_irqoff(void)125 static inline void guest_exit_irqoff(void)
126 {
127 	if (context_tracking_is_enabled())
128 		__context_tracking_exit(CONTEXT_GUEST);
129 
130 	if (vtime_accounting_cpu_enabled())
131 		vtime_guest_exit(current);
132 	else
133 		current->flags &= ~PF_VCPU;
134 }
135 
136 #else
guest_enter_irqoff(void)137 static inline void guest_enter_irqoff(void)
138 {
139 	/*
140 	 * This is running in ioctl context so its safe
141 	 * to assume that it's the stime pending cputime
142 	 * to flush.
143 	 */
144 	vtime_account_system(current);
145 	current->flags |= PF_VCPU;
146 	rcu_virt_note_context_switch(smp_processor_id());
147 }
148 
guest_exit_irqoff(void)149 static inline void guest_exit_irqoff(void)
150 {
151 	/* Flush the guest cputime we spent on the guest */
152 	vtime_account_system(current);
153 	current->flags &= ~PF_VCPU;
154 }
155 #endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */
156 
guest_enter(void)157 static inline void guest_enter(void)
158 {
159 	unsigned long flags;
160 
161 	local_irq_save(flags);
162 	guest_enter_irqoff();
163 	local_irq_restore(flags);
164 }
165 
guest_exit(void)166 static inline void guest_exit(void)
167 {
168 	unsigned long flags;
169 
170 	local_irq_save(flags);
171 	guest_exit_irqoff();
172 	local_irq_restore(flags);
173 }
174 
175 #endif
176