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 */ 103