Linux kernel mirror (for testing)
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linux
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
14extern void context_tracking_cpu_set(int cpu);
15
16/* Called with interrupts disabled. */
17extern void __context_tracking_enter(enum ctx_state state);
18extern void __context_tracking_exit(enum ctx_state state);
19
20extern void context_tracking_enter(enum ctx_state state);
21extern void context_tracking_exit(enum ctx_state state);
22extern void context_tracking_user_enter(void);
23extern void context_tracking_user_exit(void);
24
25static inline void user_enter(void)
26{
27 if (context_tracking_enabled())
28 context_tracking_enter(CONTEXT_USER);
29
30}
31static inline void user_exit(void)
32{
33 if (context_tracking_enabled())
34 context_tracking_exit(CONTEXT_USER);
35}
36
37/* Called with interrupts disabled. */
38static __always_inline void user_enter_irqoff(void)
39{
40 if (context_tracking_enabled())
41 __context_tracking_enter(CONTEXT_USER);
42
43}
44static __always_inline void user_exit_irqoff(void)
45{
46 if (context_tracking_enabled())
47 __context_tracking_exit(CONTEXT_USER);
48}
49
50static inline enum ctx_state exception_enter(void)
51{
52 enum ctx_state prev_ctx;
53
54 if (!context_tracking_enabled())
55 return 0;
56
57 prev_ctx = this_cpu_read(context_tracking.state);
58 if (prev_ctx != CONTEXT_KERNEL)
59 context_tracking_exit(prev_ctx);
60
61 return prev_ctx;
62}
63
64static inline void exception_exit(enum ctx_state prev_ctx)
65{
66 if (context_tracking_enabled()) {
67 if (prev_ctx != CONTEXT_KERNEL)
68 context_tracking_enter(prev_ctx);
69 }
70}
71
72
73/**
74 * ct_state() - return the current context tracking state if known
75 *
76 * Returns the current cpu's context tracking state if context tracking
77 * is enabled. If context tracking is disabled, returns
78 * CONTEXT_DISABLED. This should be used primarily for debugging.
79 */
80static __always_inline enum ctx_state ct_state(void)
81{
82 return context_tracking_enabled() ?
83 this_cpu_read(context_tracking.state) : CONTEXT_DISABLED;
84}
85#else
86static inline void user_enter(void) { }
87static inline void user_exit(void) { }
88static inline void user_enter_irqoff(void) { }
89static inline void user_exit_irqoff(void) { }
90static inline enum ctx_state exception_enter(void) { return 0; }
91static inline void exception_exit(enum ctx_state prev_ctx) { }
92static inline enum ctx_state ct_state(void) { return CONTEXT_DISABLED; }
93#endif /* !CONFIG_CONTEXT_TRACKING */
94
95#define CT_WARN_ON(cond) WARN_ON(context_tracking_enabled() && (cond))
96
97#ifdef CONFIG_CONTEXT_TRACKING_FORCE
98extern void context_tracking_init(void);
99#else
100static inline void context_tracking_init(void) { }
101#endif /* CONFIG_CONTEXT_TRACKING_FORCE */
102
103
104#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
105/* must be called with irqs disabled */
106static __always_inline void guest_enter_irqoff(void)
107{
108 instrumentation_begin();
109 if (vtime_accounting_enabled_this_cpu())
110 vtime_guest_enter(current);
111 else
112 current->flags |= PF_VCPU;
113 instrumentation_end();
114
115 if (context_tracking_enabled())
116 __context_tracking_enter(CONTEXT_GUEST);
117
118 /* KVM does not hold any references to rcu protected data when it
119 * switches CPU into a guest mode. In fact switching to a guest mode
120 * is very similar to exiting to userspace from rcu point of view. In
121 * addition CPU may stay in a guest mode for quite a long time (up to
122 * one time slice). Lets treat guest mode as quiescent state, just like
123 * we do with user-mode execution.
124 */
125 if (!context_tracking_enabled_this_cpu()) {
126 instrumentation_begin();
127 rcu_virt_note_context_switch(smp_processor_id());
128 instrumentation_end();
129 }
130}
131
132static __always_inline void guest_exit_irqoff(void)
133{
134 if (context_tracking_enabled())
135 __context_tracking_exit(CONTEXT_GUEST);
136
137 instrumentation_begin();
138 if (vtime_accounting_enabled_this_cpu())
139 vtime_guest_exit(current);
140 else
141 current->flags &= ~PF_VCPU;
142 instrumentation_end();
143}
144
145#else
146static __always_inline void guest_enter_irqoff(void)
147{
148 /*
149 * This is running in ioctl context so its safe
150 * to assume that it's the stime pending cputime
151 * to flush.
152 */
153 instrumentation_begin();
154 vtime_account_kernel(current);
155 current->flags |= PF_VCPU;
156 rcu_virt_note_context_switch(smp_processor_id());
157 instrumentation_end();
158}
159
160static __always_inline void guest_exit_irqoff(void)
161{
162 instrumentation_begin();
163 /* Flush the guest cputime we spent on the guest */
164 vtime_account_kernel(current);
165 current->flags &= ~PF_VCPU;
166 instrumentation_end();
167}
168#endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */
169
170static inline void guest_exit(void)
171{
172 unsigned long flags;
173
174 local_irq_save(flags);
175 guest_exit_irqoff();
176 local_irq_restore(flags);
177}
178
179#endif