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