xref: /linux/tools/perf/arch/s390/util/auxtrace.c (revision d30c1683aaecb93d2ab95685dc4300a33d3cea7a)
1 #include <errno.h>
2 #include <stdbool.h>
3 #include <stdlib.h>
4 #include <linux/kernel.h>
5 #include <linux/types.h>
6 #include <linux/bitops.h>
7 #include <linux/log2.h>
8 #include <linux/zalloc.h>
9 
10 #include "../../util/evlist.h"
11 #include "../../util/auxtrace.h"
12 #include "../../util/evsel.h"
13 #include "../../util/record.h"
14 
15 #define PERF_EVENT_CPUM_SF		0xB0000 /* Event: Basic-sampling */
16 #define PERF_EVENT_CPUM_SF_DIAG		0xBD000 /* Event: Combined-sampling */
17 #define DEFAULT_AUX_PAGES		128
18 #define DEFAULT_FREQ			4000
19 
20 static void cpumsf_free(struct auxtrace_record *itr)
21 {
22 	free(itr);
23 }
24 
25 static size_t cpumsf_info_priv_size(struct auxtrace_record *itr __maybe_unused,
26 				    struct evlist *evlist __maybe_unused)
27 {
28 	return 0;
29 }
30 
31 static int
32 cpumsf_info_fill(struct auxtrace_record *itr __maybe_unused,
33 		 struct perf_session *session __maybe_unused,
34 		 struct perf_record_auxtrace_info *auxtrace_info __maybe_unused,
35 		 size_t priv_size __maybe_unused)
36 {
37 	auxtrace_info->type = PERF_AUXTRACE_S390_CPUMSF;
38 	return 0;
39 }
40 
41 static unsigned long
42 cpumsf_reference(struct auxtrace_record *itr __maybe_unused)
43 {
44 	return 0;
45 }
46 
47 static int
48 cpumsf_recording_options(struct auxtrace_record *ar __maybe_unused,
49 			 struct evlist *evlist __maybe_unused,
50 			 struct record_opts *opts)
51 {
52 	unsigned int factor = 1;
53 	unsigned int pages;
54 
55 	opts->full_auxtrace = true;
56 
57 	/*
58 	 * The AUX buffer size should be set properly to avoid
59 	 * overflow of samples if it is not set explicitly.
60 	 * DEFAULT_AUX_PAGES is an proper size when sampling frequency
61 	 * is DEFAULT_FREQ. It is expected to hold about 1/2 second
62 	 * of sampling data. The size used for AUX buffer will scale
63 	 * according to the specified frequency and DEFAULT_FREQ.
64 	 */
65 	if (!opts->auxtrace_mmap_pages) {
66 		if (opts->user_freq != UINT_MAX)
67 			factor = (opts->user_freq + DEFAULT_FREQ
68 				  - 1) / DEFAULT_FREQ;
69 		pages = DEFAULT_AUX_PAGES * factor;
70 		opts->auxtrace_mmap_pages = roundup_pow_of_two(pages);
71 	}
72 
73 	return 0;
74 }
75 
76 static int
77 cpumsf_parse_snapshot_options(struct auxtrace_record *itr __maybe_unused,
78 			      struct record_opts *opts __maybe_unused,
79 			      const char *str __maybe_unused)
80 {
81 	return 0;
82 }
83 
84 /*
85  * auxtrace_record__init is called when perf record
86  * check if the event really need auxtrace
87  */
88 struct auxtrace_record *auxtrace_record__init(struct evlist *evlist,
89 					      int *err)
90 {
91 	struct auxtrace_record *aux;
92 	struct evsel *pos;
93 	int diagnose = 0;
94 
95 	*err = 0;
96 	if (evlist->core.nr_entries == 0)
97 		return NULL;
98 
99 	evlist__for_each_entry(evlist, pos) {
100 		if (pos->core.attr.config == PERF_EVENT_CPUM_SF_DIAG) {
101 			diagnose = 1;
102 			pos->needs_auxtrace_mmap = true;
103 			break;
104 		}
105 	}
106 
107 	if (!diagnose)
108 		return NULL;
109 
110 	/* sampling in diagnose mode. alloc aux buffer */
111 	aux = zalloc(sizeof(*aux));
112 	if (aux == NULL) {
113 		*err = -ENOMEM;
114 		return NULL;
115 	}
116 
117 	aux->parse_snapshot_options = cpumsf_parse_snapshot_options;
118 	aux->recording_options = cpumsf_recording_options;
119 	aux->info_priv_size = cpumsf_info_priv_size;
120 	aux->info_fill = cpumsf_info_fill;
121 	aux->free = cpumsf_free;
122 	aux->reference = cpumsf_reference;
123 
124 	return aux;
125 }
126