xref: /openbmc/linux/tools/perf/arch/s390/util/auxtrace.c (revision b830f94f)
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 #include <linux/zalloc.h>
7 
8 #include "../../util/evlist.h"
9 #include "../../util/auxtrace.h"
10 #include "../../util/evsel.h"
11 
12 #define PERF_EVENT_CPUM_SF		0xB0000 /* Event: Basic-sampling */
13 #define PERF_EVENT_CPUM_SF_DIAG		0xBD000 /* Event: Combined-sampling */
14 #define DEFAULT_AUX_PAGES		128
15 #define DEFAULT_FREQ			4000
16 
17 static void cpumsf_free(struct auxtrace_record *itr)
18 {
19 	free(itr);
20 }
21 
22 static size_t cpumsf_info_priv_size(struct auxtrace_record *itr __maybe_unused,
23 				    struct perf_evlist *evlist __maybe_unused)
24 {
25 	return 0;
26 }
27 
28 static int
29 cpumsf_info_fill(struct auxtrace_record *itr __maybe_unused,
30 		 struct perf_session *session __maybe_unused,
31 		 struct auxtrace_info_event *auxtrace_info __maybe_unused,
32 		 size_t priv_size __maybe_unused)
33 {
34 	auxtrace_info->type = PERF_AUXTRACE_S390_CPUMSF;
35 	return 0;
36 }
37 
38 static unsigned long
39 cpumsf_reference(struct auxtrace_record *itr __maybe_unused)
40 {
41 	return 0;
42 }
43 
44 static int
45 cpumsf_recording_options(struct auxtrace_record *ar __maybe_unused,
46 			 struct perf_evlist *evlist __maybe_unused,
47 			 struct record_opts *opts)
48 {
49 	unsigned int factor = 1;
50 	unsigned int pages;
51 
52 	opts->full_auxtrace = true;
53 
54 	/*
55 	 * The AUX buffer size should be set properly to avoid
56 	 * overflow of samples if it is not set explicitly.
57 	 * DEFAULT_AUX_PAGES is an proper size when sampling frequency
58 	 * is DEFAULT_FREQ. It is expected to hold about 1/2 second
59 	 * of sampling data. The size used for AUX buffer will scale
60 	 * according to the specified frequency and DEFAULT_FREQ.
61 	 */
62 	if (!opts->auxtrace_mmap_pages) {
63 		if (opts->user_freq != UINT_MAX)
64 			factor = (opts->user_freq + DEFAULT_FREQ
65 				  - 1) / DEFAULT_FREQ;
66 		pages = DEFAULT_AUX_PAGES * factor;
67 		opts->auxtrace_mmap_pages = roundup_pow_of_two(pages);
68 	}
69 
70 	return 0;
71 }
72 
73 static int
74 cpumsf_parse_snapshot_options(struct auxtrace_record *itr __maybe_unused,
75 			      struct record_opts *opts __maybe_unused,
76 			      const char *str __maybe_unused)
77 {
78 	return 0;
79 }
80 
81 /*
82  * auxtrace_record__init is called when perf record
83  * check if the event really need auxtrace
84  */
85 struct auxtrace_record *auxtrace_record__init(struct perf_evlist *evlist,
86 					      int *err)
87 {
88 	struct auxtrace_record *aux;
89 	struct perf_evsel *pos;
90 	int diagnose = 0;
91 
92 	*err = 0;
93 	if (evlist->nr_entries == 0)
94 		return NULL;
95 
96 	evlist__for_each_entry(evlist, pos) {
97 		if (pos->attr.config == PERF_EVENT_CPUM_SF_DIAG) {
98 			diagnose = 1;
99 			break;
100 		}
101 	}
102 
103 	if (!diagnose)
104 		return NULL;
105 
106 	/* sampling in diagnose mode. alloc aux buffer */
107 	aux = zalloc(sizeof(*aux));
108 	if (aux == NULL) {
109 		*err = -ENOMEM;
110 		return NULL;
111 	}
112 
113 	aux->parse_snapshot_options = cpumsf_parse_snapshot_options;
114 	aux->recording_options = cpumsf_recording_options;
115 	aux->info_priv_size = cpumsf_info_priv_size;
116 	aux->info_fill = cpumsf_info_fill;
117 	aux->free = cpumsf_free;
118 	aux->reference = cpumsf_reference;
119 
120 	return aux;
121 }
122