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
perf_mmap__read_head(struct perf_mmap * mm)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
perf_mmap__write_tail(struct perf_mmap * md,u64 tail)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 */
103
