GNU Linux-libre 4.19.211-gnu1
[releases.git] / tools / perf / util / mmap.h
1 #ifndef __PERF_MMAP_H
2 #define __PERF_MMAP_H 1
3
4 #include <linux/compiler.h>
5 #include <linux/refcount.h>
6 #include <linux/types.h>
7 #include <asm/barrier.h>
8 #include <stdbool.h>
9 #include "auxtrace.h"
10 #include "event.h"
11
12 /**
13  * struct perf_mmap - perf's ring buffer mmap details
14  *
15  * @refcnt - e.g. code using PERF_EVENT_IOC_SET_OUTPUT to share this
16  */
17 struct perf_mmap {
18         void             *base;
19         int              mask;
20         int              fd;
21         int              cpu;
22         refcount_t       refcnt;
23         u64              prev;
24         u64              start;
25         u64              end;
26         bool             overwrite;
27         struct auxtrace_mmap auxtrace_mmap;
28         char             event_copy[PERF_SAMPLE_MAX_SIZE] __aligned(8);
29 };
30
31 /*
32  * State machine of bkw_mmap_state:
33  *
34  *                     .________________(forbid)_____________.
35  *                     |                                     V
36  * NOTREADY --(0)--> RUNNING --(1)--> DATA_PENDING --(2)--> EMPTY
37  *                     ^  ^              |   ^               |
38  *                     |  |__(forbid)____/   |___(forbid)___/|
39  *                     |                                     |
40  *                      \_________________(3)_______________/
41  *
42  * NOTREADY     : Backward ring buffers are not ready
43  * RUNNING      : Backward ring buffers are recording
44  * DATA_PENDING : We are required to collect data from backward ring buffers
45  * EMPTY        : We have collected data from backward ring buffers.
46  *
47  * (0): Setup backward ring buffer
48  * (1): Pause ring buffers for reading
49  * (2): Read from ring buffers
50  * (3): Resume ring buffers for recording
51  */
52 enum bkw_mmap_state {
53         BKW_MMAP_NOTREADY,
54         BKW_MMAP_RUNNING,
55         BKW_MMAP_DATA_PENDING,
56         BKW_MMAP_EMPTY,
57 };
58
59 struct mmap_params {
60         int                         prot, mask;
61         struct auxtrace_mmap_params auxtrace_mp;
62 };
63
64 int perf_mmap__mmap(struct perf_mmap *map, struct mmap_params *mp, int fd, int cpu);
65 void perf_mmap__munmap(struct perf_mmap *map);
66
67 void perf_mmap__get(struct perf_mmap *map);
68 void perf_mmap__put(struct perf_mmap *map);
69
70 void perf_mmap__consume(struct perf_mmap *map);
71
72 static inline u64 perf_mmap__read_head(struct perf_mmap *mm)
73 {
74         struct perf_event_mmap_page *pc = mm->base;
75         u64 head = READ_ONCE(pc->data_head);
76         rmb();
77         return head;
78 }
79
80 static inline void perf_mmap__write_tail(struct perf_mmap *md, u64 tail)
81 {
82         struct perf_event_mmap_page *pc = md->base;
83
84         /*
85          * ensure all reads are done before we write the tail out.
86          */
87         mb();
88         pc->data_tail = tail;
89 }
90
91 union perf_event *perf_mmap__read_forward(struct perf_mmap *map);
92
93 union perf_event *perf_mmap__read_event(struct perf_mmap *map);
94
95 int perf_mmap__push(struct perf_mmap *md, void *to,
96                     int push(void *to, void *buf, size_t size));
97
98 size_t perf_mmap__mmap_len(struct perf_mmap *map);
99
100 int perf_mmap__read_init(struct perf_mmap *md);
101 void perf_mmap__read_done(struct perf_mmap *map);
102 #endif /*__PERF_MMAP_H */