xref: /openbmc/linux/tools/perf/arch/s390/util/auxtrace.c (revision 82e6fdd6)
1 #include <stdbool.h>
2 #include <linux/kernel.h>
3 #include <linux/types.h>
4 #include <linux/bitops.h>
5 #include <linux/log2.h>
6 
7 #include "../../util/evlist.h"
8 #include "../../util/auxtrace.h"
9 #include "../../util/evsel.h"
10 
11 #define PERF_EVENT_CPUM_SF		0xB0000 /* Event: Basic-sampling */
12 #define PERF_EVENT_CPUM_SF_DIAG		0xBD000 /* Event: Combined-sampling */
13 #define DEFAULT_AUX_PAGES		128
14 #define DEFAULT_FREQ			4000
15 
16 static void cpumsf_free(struct auxtrace_record *itr)
17 {
18 	free(itr);
19 }
20 
21 static size_t cpumsf_info_priv_size(struct auxtrace_record *itr __maybe_unused,
22 				    struct perf_evlist *evlist __maybe_unused)
23 {
24 	return 0;
25 }
26 
27 static int
28 cpumsf_info_fill(struct auxtrace_record *itr __maybe_unused,
29 		 struct perf_session *session __maybe_unused,
30 		 struct auxtrace_info_event *auxtrace_info __maybe_unused,
31 		 size_t priv_size __maybe_unused)
32 {
33 	return 0;
34 }
35 
36 static unsigned long
37 cpumsf_reference(struct auxtrace_record *itr __maybe_unused)
38 {
39 	return 0;
40 }
41 
42 static int
43 cpumsf_recording_options(struct auxtrace_record *ar __maybe_unused,
44 			 struct perf_evlist *evlist __maybe_unused,
45 			 struct record_opts *opts)
46 {
47 	unsigned int factor = 1;
48 	unsigned int pages;
49 
50 	opts->full_auxtrace = true;
51 
52 	/*
53 	 * The AUX buffer size should be set properly to avoid
54 	 * overflow of samples if it is not set explicitly.
55 	 * DEFAULT_AUX_PAGES is an proper size when sampling frequency
56 	 * is DEFAULT_FREQ. It is expected to hold about 1/2 second
57 	 * of sampling data. The size used for AUX buffer will scale
58 	 * according to the specified frequency and DEFAULT_FREQ.
59 	 */
60 	if (!opts->auxtrace_mmap_pages) {
61 		if (opts->user_freq != UINT_MAX)
62 			factor = (opts->user_freq + DEFAULT_FREQ
63 				  - 1) / DEFAULT_FREQ;
64 		pages = DEFAULT_AUX_PAGES * factor;
65 		opts->auxtrace_mmap_pages = roundup_pow_of_two(pages);
66 	}
67 
68 	return 0;
69 }
70 
71 static int
72 cpumsf_parse_snapshot_options(struct auxtrace_record *itr __maybe_unused,
73 			      struct record_opts *opts __maybe_unused,
74 			      const char *str __maybe_unused)
75 {
76 	return 0;
77 }
78 
79 /*
80  * auxtrace_record__init is called when perf record
81  * check if the event really need auxtrace
82  */
83 struct auxtrace_record *auxtrace_record__init(struct perf_evlist *evlist,
84 					      int *err)
85 {
86 	struct auxtrace_record *aux;
87 	struct perf_evsel *pos;
88 	int diagnose = 0;
89 
90 	if (evlist->nr_entries == 0)
91 		return NULL;
92 
93 	evlist__for_each_entry(evlist, pos) {
94 		if (pos->attr.config == PERF_EVENT_CPUM_SF_DIAG) {
95 			diagnose = 1;
96 			break;
97 		}
98 	}
99 
100 	if (!diagnose)
101 		return NULL;
102 
103 	/* sampling in diagnose mode. alloc aux buffer */
104 	aux = zalloc(sizeof(*aux));
105 	if (aux == NULL) {
106 		*err = -ENOMEM;
107 		return NULL;
108 	}
109 
110 	aux->parse_snapshot_options = cpumsf_parse_snapshot_options;
111 	aux->recording_options = cpumsf_recording_options;
112 	aux->info_priv_size = cpumsf_info_priv_size;
113 	aux->info_fill = cpumsf_info_fill;
114 	aux->free = cpumsf_free;
115 	aux->reference = cpumsf_reference;
116 
117 	return aux;
118 }
119