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
12extern void context_tracking_cpu_set(int cpu);
13
14/* Called with interrupts disabled. */
15extern void __context_tracking_enter(enum ctx_state state);
16extern void __context_tracking_exit(enum ctx_state state);
17
18extern void context_tracking_enter(enum ctx_state state);
19extern void context_tracking_exit(enum ctx_state state);
20extern void context_tracking_user_enter(void);
21extern void context_tracking_user_exit(void);
22
23static inline void user_enter(void)
24{
25 if (context_tracking_is_enabled())
26 context_tracking_enter(CONTEXT_USER);
27
28}
29static 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. */
36static inline void user_enter_irqoff(void)
37{
38 if (context_tracking_is_enabled())
39 __context_tracking_enter(CONTEXT_USER);
40
41}
42static inline void user_exit_irqoff(void)
43{
44 if (context_tracking_is_enabled())
45 __context_tracking_exit(CONTEXT_USER);
46}
47
48static 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
62static 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 */
78static 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
84static inline void user_enter(void) { }
85static inline void user_exit(void) { }
86static inline void user_enter_irqoff(void) { }
87static inline void user_exit_irqoff(void) { }
88static inline enum ctx_state exception_enter(void) { return 0; }
89static inline void exception_exit(enum ctx_state prev_ctx) { }
90static 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
96extern void context_tracking_init(void);
97#else
98static 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 */
104static 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
125static 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
137static 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
149static 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
157static 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
166static 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