1 #include <linux/kernel.h>
2 #include <linux/bits.h>
3 #include <linux/bitfield.h>
4 #include <stdio.h>
5 #include <stdlib.h>
6 #include <perf/cpumap.h>
7 #include <api/fs/fs.h>
8 #include <errno.h>
9 #include "debug.h"
10 #include "header.h"
11
12 #define MIDR "/regs/identification/midr_el1"
13 #define MIDR_SIZE 19
14 #define MIDR_REVISION_MASK GENMASK(3, 0)
15 #define MIDR_VARIANT_MASK GENMASK(23, 20)
16
_get_cpuid(char * buf,size_t sz,struct perf_cpu_map * cpus)17 static int _get_cpuid(char *buf, size_t sz, struct perf_cpu_map *cpus)
18 {
19 const char *sysfs = sysfs__mountpoint();
20 struct perf_cpu cpu;
21 int idx, ret = EINVAL;
22
23 if (!sysfs || sz < MIDR_SIZE)
24 return EINVAL;
25
26 perf_cpu_map__for_each_cpu(cpu, idx, cpus) {
27 char path[PATH_MAX];
28 FILE *file;
29
30 scnprintf(path, PATH_MAX, "%s/devices/system/cpu/cpu%d" MIDR,
31 sysfs, cpu.cpu);
32
33 file = fopen(path, "r");
34 if (!file) {
35 pr_debug("fopen failed for file %s\n", path);
36 continue;
37 }
38
39 if (!fgets(buf, MIDR_SIZE, file)) {
40 fclose(file);
41 continue;
42 }
43 fclose(file);
44
45 /* got midr break loop */
46 ret = 0;
47 break;
48 }
49
50 return ret;
51 }
52
get_cpuid(char * buf,size_t sz)53 int get_cpuid(char *buf, size_t sz)
54 {
55 struct perf_cpu_map *cpus = perf_cpu_map__new_online_cpus();
56 int ret;
57
58 if (!cpus)
59 return EINVAL;
60
61 ret = _get_cpuid(buf, sz, cpus);
62
63 perf_cpu_map__put(cpus);
64
65 return ret;
66 }
67
get_cpuid_str(struct perf_pmu * pmu)68 char *get_cpuid_str(struct perf_pmu *pmu)
69 {
70 char *buf = NULL;
71 int res;
72
73 if (!pmu || !pmu->cpus)
74 return NULL;
75
76 buf = malloc(MIDR_SIZE);
77 if (!buf)
78 return NULL;
79
80 /* read midr from list of cpus mapped to this pmu */
81 res = _get_cpuid(buf, MIDR_SIZE, pmu->cpus);
82 if (res) {
83 pr_err("failed to get cpuid string for PMU %s\n", pmu->name);
84 free(buf);
85 buf = NULL;
86 }
87
88 return buf;
89 }
90
91 /*
92 * Return 0 if idstr is a higher or equal to version of the same part as
93 * mapcpuid. Therefore, if mapcpuid has 0 for revision and variant then any
94 * version of idstr will match as long as it's the same CPU type.
95 *
96 * Return 1 if the CPU type is different or the version of idstr is lower.
97 */
strcmp_cpuid_str(const char * mapcpuid,const char * idstr)98 int strcmp_cpuid_str(const char *mapcpuid, const char *idstr)
99 {
100 u64 map_id = strtoull(mapcpuid, NULL, 16);
101 char map_id_variant = FIELD_GET(MIDR_VARIANT_MASK, map_id);
102 char map_id_revision = FIELD_GET(MIDR_REVISION_MASK, map_id);
103 u64 id = strtoull(idstr, NULL, 16);
104 char id_variant = FIELD_GET(MIDR_VARIANT_MASK, id);
105 char id_revision = FIELD_GET(MIDR_REVISION_MASK, id);
106 u64 id_fields = ~(MIDR_VARIANT_MASK | MIDR_REVISION_MASK);
107
108 /* Compare without version first */
109 if ((map_id & id_fields) != (id & id_fields))
110 return 1;
111
112 /*
113 * ID matches, now compare version.
114 *
115 * Arm revisions (like r0p0) are compared here like two digit semver
116 * values eg. 1.3 < 2.0 < 2.1 < 2.2.
117 *
118 * r = high value = 'Variant' field in MIDR
119 * p = low value = 'Revision' field in MIDR
120 *
121 */
122 if (id_variant > map_id_variant)
123 return 0;
124
125 if (id_variant == map_id_variant && id_revision >= map_id_revision)
126 return 0;
127
128 /*
129 * variant is less than mapfile variant or variants are the same but
130 * the revision doesn't match. Return no match.
131 */
132 return 1;
133 }
134