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