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1 | /* |
2 | * auxtrace.h: AUX area trace support | |
3 | * Copyright (c) 2013-2015, Intel Corporation. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms and conditions of the GNU General Public License, | |
7 | * version 2, as published by the Free Software Foundation. | |
8 | * | |
9 | * This program is distributed in the hope it will be useful, but WITHOUT | |
10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
12 | * more details. | |
13 | * | |
14 | */ | |
15 | ||
16 | #ifndef __PERF_AUXTRACE_H | |
17 | #define __PERF_AUXTRACE_H | |
18 | ||
19 | #include <sys/types.h> | |
20 | #include <stdbool.h> | |
21 | ||
22 | #include <linux/perf_event.h> | |
23 | #include <linux/types.h> | |
24 | ||
25 | #include "../perf.h" | |
26 | ||
27 | struct perf_evlist; | |
28 | ||
29 | /** | |
30 | * struct auxtrace_mmap - records an mmap of the auxtrace buffer. | |
31 | * @base: address of mapped area | |
32 | * @userpg: pointer to buffer's perf_event_mmap_page | |
33 | * @mask: %0 if @len is not a power of two, otherwise (@len - %1) | |
34 | * @len: size of mapped area | |
35 | * @prev: previous aux_head | |
36 | * @idx: index of this mmap | |
37 | * @tid: tid for a per-thread mmap (also set if there is only 1 tid on a per-cpu | |
38 | * mmap) otherwise %0 | |
39 | * @cpu: cpu number for a per-cpu mmap otherwise %-1 | |
40 | */ | |
41 | struct auxtrace_mmap { | |
42 | void *base; | |
43 | void *userpg; | |
44 | size_t mask; | |
45 | size_t len; | |
46 | u64 prev; | |
47 | int idx; | |
48 | pid_t tid; | |
49 | int cpu; | |
50 | }; | |
51 | ||
52 | /** | |
53 | * struct auxtrace_mmap_params - parameters to set up struct auxtrace_mmap. | |
54 | * @mask: %0 if @len is not a power of two, otherwise (@len - %1) | |
55 | * @offset: file offset of mapped area | |
56 | * @len: size of mapped area | |
57 | * @prot: mmap memory protection | |
58 | * @idx: index of this mmap | |
59 | * @tid: tid for a per-thread mmap (also set if there is only 1 tid on a per-cpu | |
60 | * mmap) otherwise %0 | |
61 | * @cpu: cpu number for a per-cpu mmap otherwise %-1 | |
62 | */ | |
63 | struct auxtrace_mmap_params { | |
64 | size_t mask; | |
65 | off_t offset; | |
66 | size_t len; | |
67 | int prot; | |
68 | int idx; | |
69 | pid_t tid; | |
70 | int cpu; | |
71 | }; | |
72 | ||
73 | static inline u64 auxtrace_mmap__read_head(struct auxtrace_mmap *mm) | |
74 | { | |
75 | struct perf_event_mmap_page *pc = mm->userpg; | |
76 | #if BITS_PER_LONG == 64 || !defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT) | |
77 | u64 head = ACCESS_ONCE(pc->aux_head); | |
78 | #else | |
79 | u64 head = __sync_val_compare_and_swap(&pc->aux_head, 0, 0); | |
80 | #endif | |
81 | ||
82 | /* Ensure all reads are done after we read the head */ | |
83 | rmb(); | |
84 | return head; | |
85 | } | |
86 | ||
87 | static inline void auxtrace_mmap__write_tail(struct auxtrace_mmap *mm, u64 tail) | |
88 | { | |
89 | struct perf_event_mmap_page *pc = mm->userpg; | |
90 | #if BITS_PER_LONG != 64 && defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT) | |
91 | u64 old_tail; | |
92 | #endif | |
93 | ||
94 | /* Ensure all reads are done before we write the tail out */ | |
95 | mb(); | |
96 | #if BITS_PER_LONG == 64 || !defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT) | |
97 | pc->aux_tail = tail; | |
98 | #else | |
99 | do { | |
100 | old_tail = __sync_val_compare_and_swap(&pc->aux_tail, 0, 0); | |
101 | } while (!__sync_bool_compare_and_swap(&pc->aux_tail, old_tail, tail)); | |
102 | #endif | |
103 | } | |
104 | ||
105 | int auxtrace_mmap__mmap(struct auxtrace_mmap *mm, | |
106 | struct auxtrace_mmap_params *mp, | |
107 | void *userpg, int fd); | |
108 | void auxtrace_mmap__munmap(struct auxtrace_mmap *mm); | |
109 | void auxtrace_mmap_params__init(struct auxtrace_mmap_params *mp, | |
110 | off_t auxtrace_offset, | |
111 | unsigned int auxtrace_pages, | |
112 | bool auxtrace_overwrite); | |
113 | void auxtrace_mmap_params__set_idx(struct auxtrace_mmap_params *mp, | |
114 | struct perf_evlist *evlist, int idx, | |
115 | bool per_cpu); | |
116 | ||
117 | #endif |