103 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			103 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
#ifndef __PERF_MMAP_H
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#define __PERF_MMAP_H 1
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#include <linux/compiler.h>
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#include <linux/refcount.h>
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#include <linux/types.h>
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#include <asm/barrier.h>
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#include <stdbool.h>
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#include "auxtrace.h"
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#include "event.h"
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/**
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 * struct perf_mmap - perf's ring buffer mmap details
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 *
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 * @refcnt - e.g. code using PERF_EVENT_IOC_SET_OUTPUT to share this
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 */
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struct perf_mmap {
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	void		 *base;
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	int		 mask;
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	int		 fd;
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	int		 cpu;
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	refcount_t	 refcnt;
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	u64		 prev;
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	u64		 start;
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	u64		 end;
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	bool		 overwrite;
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	struct auxtrace_mmap auxtrace_mmap;
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	char		 event_copy[PERF_SAMPLE_MAX_SIZE] __aligned(8);
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};
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/*
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 * State machine of bkw_mmap_state:
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 *
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 *                     .________________(forbid)_____________.
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 *                     |                                     V
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 * NOTREADY --(0)--> RUNNING --(1)--> DATA_PENDING --(2)--> EMPTY
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 *                     ^  ^              |   ^               |
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 *                     |  |__(forbid)____/   |___(forbid)___/|
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 *                     |                                     |
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 *                      \_________________(3)_______________/
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 *
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 * NOTREADY     : Backward ring buffers are not ready
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 * RUNNING      : Backward ring buffers are recording
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 * DATA_PENDING : We are required to collect data from backward ring buffers
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 * EMPTY        : We have collected data from backward ring buffers.
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 *
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 * (0): Setup backward ring buffer
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 * (1): Pause ring buffers for reading
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 * (2): Read from ring buffers
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 * (3): Resume ring buffers for recording
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 */
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enum bkw_mmap_state {
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	BKW_MMAP_NOTREADY,
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	BKW_MMAP_RUNNING,
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	BKW_MMAP_DATA_PENDING,
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	BKW_MMAP_EMPTY,
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};
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struct mmap_params {
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	int			    prot, mask;
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	struct auxtrace_mmap_params auxtrace_mp;
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};
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int perf_mmap__mmap(struct perf_mmap *map, struct mmap_params *mp, int fd, int cpu);
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void perf_mmap__munmap(struct perf_mmap *map);
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void perf_mmap__get(struct perf_mmap *map);
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void perf_mmap__put(struct perf_mmap *map);
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void perf_mmap__consume(struct perf_mmap *map);
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static inline u64 perf_mmap__read_head(struct perf_mmap *mm)
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{
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	struct perf_event_mmap_page *pc = mm->base;
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	u64 head = READ_ONCE(pc->data_head);
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	rmb();
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	return head;
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}
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static inline void perf_mmap__write_tail(struct perf_mmap *md, u64 tail)
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{
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	struct perf_event_mmap_page *pc = md->base;
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	/*
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	 * ensure all reads are done before we write the tail out.
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	 */
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	mb();
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	pc->data_tail = tail;
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}
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union perf_event *perf_mmap__read_forward(struct perf_mmap *map);
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union perf_event *perf_mmap__read_event(struct perf_mmap *map);
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int perf_mmap__push(struct perf_mmap *md, void *to,
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		    int push(void *to, void *buf, size_t size));
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size_t perf_mmap__mmap_len(struct perf_mmap *map);
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int perf_mmap__read_init(struct perf_mmap *md);
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void perf_mmap__read_done(struct perf_mmap *map);
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#endif /*__PERF_MMAP_H */
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