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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
e7358b3b FW |
2 | #ifndef _LINUX_CONTEXT_TRACKING_STATE_H |
3 | #define _LINUX_CONTEXT_TRACKING_STATE_H | |
4 | ||
5 | #include <linux/percpu.h> | |
6 | #include <linux/static_key.h> | |
6f0e6c15 | 7 | #include <linux/context_tracking_irq.h> |
e7358b3b | 8 | |
17147677 FW |
9 | /* Offset to allow distinguishing irq vs. task-based idle entry/exit. */ |
10 | #define DYNTICK_IRQ_NONIDLE ((LONG_MAX / 2) + 1) | |
11 | ||
62e2412d | 12 | enum ctx_state { |
17147677 FW |
13 | CONTEXT_DISABLED = -1, /* returned by ct_state() if unknown */ |
14 | CONTEXT_KERNEL = 0, | |
15 | CONTEXT_IDLE = 1, | |
16 | CONTEXT_USER = 2, | |
17 | CONTEXT_GUEST = 3, | |
18 | CONTEXT_MAX = 4, | |
62e2412d FW |
19 | }; |
20 | ||
17147677 FW |
21 | /* Even value for idle, else odd. */ |
22 | #define RCU_DYNTICKS_IDX CONTEXT_MAX | |
23 | ||
24 | #define CT_STATE_MASK (CONTEXT_MAX - 1) | |
25 | #define CT_DYNTICKS_MASK (~CT_STATE_MASK) | |
95e04f48 | 26 | |
e7358b3b | 27 | struct context_tracking { |
62e2412d | 28 | #ifdef CONFIG_CONTEXT_TRACKING_USER |
e7358b3b FW |
29 | /* |
30 | * When active is false, probes are unset in order | |
31 | * to minimize overhead: TIF flags are cleared | |
32 | * and calls to user_enter/exit are ignored. This | |
33 | * may be further optimized using static keys. | |
34 | */ | |
35 | bool active; | |
aed5ed47 | 36 | int recursion; |
17147677 FW |
37 | #endif |
38 | #ifdef CONFIG_CONTEXT_TRACKING | |
39 | atomic_t state; | |
62e2412d FW |
40 | #endif |
41 | #ifdef CONFIG_CONTEXT_TRACKING_IDLE | |
904e600e | 42 | long dynticks_nesting; /* Track process nesting level. */ |
95e04f48 | 43 | long dynticks_nmi_nesting; /* Track irq/NMI nesting level. */ |
62e2412d | 44 | #endif |
e7358b3b FW |
45 | }; |
46 | ||
62e2412d FW |
47 | #ifdef CONFIG_CONTEXT_TRACKING |
48 | DECLARE_PER_CPU(struct context_tracking, context_tracking); | |
f87d2867 | 49 | #endif |
17147677 | 50 | |
f87d2867 | 51 | #ifdef CONFIG_CONTEXT_TRACKING_USER |
17147677 FW |
52 | static __always_inline int __ct_state(void) |
53 | { | |
1dcaa3b4 | 54 | return arch_atomic_read(this_cpu_ptr(&context_tracking.state)) & CT_STATE_MASK; |
17147677 | 55 | } |
62e2412d FW |
56 | #endif |
57 | ||
58 | #ifdef CONFIG_CONTEXT_TRACKING_IDLE | |
59 | static __always_inline int ct_dynticks(void) | |
60 | { | |
17147677 | 61 | return atomic_read(this_cpu_ptr(&context_tracking.state)) & CT_DYNTICKS_MASK; |
62e2412d FW |
62 | } |
63 | ||
64 | static __always_inline int ct_dynticks_cpu(int cpu) | |
65 | { | |
66 | struct context_tracking *ct = per_cpu_ptr(&context_tracking, cpu); | |
67 | ||
17147677 | 68 | return atomic_read(&ct->state) & CT_DYNTICKS_MASK; |
62e2412d FW |
69 | } |
70 | ||
71 | static __always_inline int ct_dynticks_cpu_acquire(int cpu) | |
72 | { | |
73 | struct context_tracking *ct = per_cpu_ptr(&context_tracking, cpu); | |
74 | ||
17147677 | 75 | return atomic_read_acquire(&ct->state) & CT_DYNTICKS_MASK; |
62e2412d | 76 | } |
904e600e FW |
77 | |
78 | static __always_inline long ct_dynticks_nesting(void) | |
79 | { | |
80 | return __this_cpu_read(context_tracking.dynticks_nesting); | |
81 | } | |
82 | ||
83 | static __always_inline long ct_dynticks_nesting_cpu(int cpu) | |
84 | { | |
85 | struct context_tracking *ct = per_cpu_ptr(&context_tracking, cpu); | |
86 | ||
87 | return ct->dynticks_nesting; | |
88 | } | |
95e04f48 FW |
89 | |
90 | static __always_inline long ct_dynticks_nmi_nesting(void) | |
91 | { | |
92 | return __this_cpu_read(context_tracking.dynticks_nmi_nesting); | |
93 | } | |
94 | ||
95 | static __always_inline long ct_dynticks_nmi_nesting_cpu(int cpu) | |
96 | { | |
97 | struct context_tracking *ct = per_cpu_ptr(&context_tracking, cpu); | |
98 | ||
99 | return ct->dynticks_nmi_nesting; | |
100 | } | |
62e2412d FW |
101 | #endif /* #ifdef CONFIG_CONTEXT_TRACKING_IDLE */ |
102 | ||
24a9c541 | 103 | #ifdef CONFIG_CONTEXT_TRACKING_USER |
74c57875 | 104 | extern struct static_key_false context_tracking_key; |
e7358b3b | 105 | |
0372007f | 106 | static __always_inline bool context_tracking_enabled(void) |
58135f57 | 107 | { |
74c57875 | 108 | return static_branch_unlikely(&context_tracking_key); |
58135f57 | 109 | } |
d0df09eb | 110 | |
0372007f | 111 | static __always_inline bool context_tracking_enabled_cpu(int cpu) |
097f2541 | 112 | { |
023e9deb | 113 | return context_tracking_enabled() && per_cpu(context_tracking.active, cpu); |
097f2541 FW |
114 | } |
115 | ||
84e0dacd | 116 | static inline bool context_tracking_enabled_this_cpu(void) |
e7358b3b | 117 | { |
023e9deb | 118 | return context_tracking_enabled() && __this_cpu_read(context_tracking.active); |
e7358b3b FW |
119 | } |
120 | ||
17147677 FW |
121 | /** |
122 | * ct_state() - return the current context tracking state if known | |
123 | * | |
124 | * Returns the current cpu's context tracking state if context tracking | |
125 | * is enabled. If context tracking is disabled, returns | |
126 | * CONTEXT_DISABLED. This should be used primarily for debugging. | |
127 | */ | |
128 | static __always_inline int ct_state(void) | |
129 | { | |
130 | int ret; | |
131 | ||
132 | if (!context_tracking_enabled()) | |
133 | return CONTEXT_DISABLED; | |
134 | ||
135 | preempt_disable(); | |
136 | ret = __ct_state(); | |
137 | preempt_enable(); | |
138 | ||
139 | return ret; | |
140 | } | |
141 | ||
e7358b3b | 142 | #else |
620f8d3b PZ |
143 | static __always_inline bool context_tracking_enabled(void) { return false; } |
144 | static __always_inline bool context_tracking_enabled_cpu(int cpu) { return false; } | |
145 | static __always_inline bool context_tracking_enabled_this_cpu(void) { return false; } | |
24a9c541 | 146 | #endif /* CONFIG_CONTEXT_TRACKING_USER */ |
e7358b3b FW |
147 | |
148 | #endif |