Linux kernel mirror (for testing)
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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 (IS_ENABLED(CONFIG_HAVE_CONTEXT_TRACKING_OFFSTACK) ||
55 !context_tracking_enabled())
56 return 0;
57
58 prev_ctx = this_cpu_read(context_tracking.state);
59 if (prev_ctx != CONTEXT_KERNEL)
60 context_tracking_exit(prev_ctx);
61
62 return prev_ctx;
63}
64
65static inline void exception_exit(enum ctx_state prev_ctx)
66{
67 if (!IS_ENABLED(CONFIG_HAVE_CONTEXT_TRACKING_OFFSTACK) &&
68 context_tracking_enabled()) {
69 if (prev_ctx != CONTEXT_KERNEL)
70 context_tracking_enter(prev_ctx);
71 }
72}
73
74
75/**
76 * ct_state() - return the current context tracking state if known
77 *
78 * Returns the current cpu's context tracking state if context tracking
79 * is enabled. If context tracking is disabled, returns
80 * CONTEXT_DISABLED. This should be used primarily for debugging.
81 */
82static __always_inline enum ctx_state ct_state(void)
83{
84 return context_tracking_enabled() ?
85 this_cpu_read(context_tracking.state) : CONTEXT_DISABLED;
86}
87#else
88static inline void user_enter(void) { }
89static inline void user_exit(void) { }
90static inline void user_enter_irqoff(void) { }
91static inline void user_exit_irqoff(void) { }
92static inline enum ctx_state exception_enter(void) { return 0; }
93static inline void exception_exit(enum ctx_state prev_ctx) { }
94static inline enum ctx_state ct_state(void) { return CONTEXT_DISABLED; }
95#endif /* !CONFIG_CONTEXT_TRACKING */
96
97#define CT_WARN_ON(cond) WARN_ON(context_tracking_enabled() && (cond))
98
99#ifdef CONFIG_CONTEXT_TRACKING_FORCE
100extern void context_tracking_init(void);
101#else
102static inline void context_tracking_init(void) { }
103#endif /* CONFIG_CONTEXT_TRACKING_FORCE */
104
105
106#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
107/* must be called with irqs disabled */
108static __always_inline void guest_enter_irqoff(void)
109{
110 instrumentation_begin();
111 if (vtime_accounting_enabled_this_cpu())
112 vtime_guest_enter(current);
113 else
114 current->flags |= PF_VCPU;
115 instrumentation_end();
116
117 if (context_tracking_enabled())
118 __context_tracking_enter(CONTEXT_GUEST);
119
120 /* KVM does not hold any references to rcu protected data when it
121 * switches CPU into a guest mode. In fact switching to a guest mode
122 * is very similar to exiting to userspace from rcu point of view. In
123 * addition CPU may stay in a guest mode for quite a long time (up to
124 * one time slice). Lets treat guest mode as quiescent state, just like
125 * we do with user-mode execution.
126 */
127 if (!context_tracking_enabled_this_cpu()) {
128 instrumentation_begin();
129 rcu_virt_note_context_switch(smp_processor_id());
130 instrumentation_end();
131 }
132}
133
134static __always_inline void guest_exit_irqoff(void)
135{
136 if (context_tracking_enabled())
137 __context_tracking_exit(CONTEXT_GUEST);
138
139 instrumentation_begin();
140 if (vtime_accounting_enabled_this_cpu())
141 vtime_guest_exit(current);
142 else
143 current->flags &= ~PF_VCPU;
144 instrumentation_end();
145}
146
147#else
148static __always_inline void guest_enter_irqoff(void)
149{
150 /*
151 * This is running in ioctl context so its safe
152 * to assume that it's the stime pending cputime
153 * to flush.
154 */
155 instrumentation_begin();
156 vtime_account_kernel(current);
157 current->flags |= PF_VCPU;
158 rcu_virt_note_context_switch(smp_processor_id());
159 instrumentation_end();
160}
161
162static __always_inline void guest_exit_irqoff(void)
163{
164 instrumentation_begin();
165 /* Flush the guest cputime we spent on the guest */
166 vtime_account_kernel(current);
167 current->flags &= ~PF_VCPU;
168 instrumentation_end();
169}
170#endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */
171
172static inline void guest_exit(void)
173{
174 unsigned long flags;
175
176 local_irq_save(flags);
177 guest_exit_irqoff();
178 local_irq_restore(flags);
179}
180
181#endif