tools/perf/arch/arm64/util/header.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <api/fs/fs.h>
   4 #include "header.h"
   5
   6 #define MIDR "/regs/identification/midr_el1"
   7 #define MIDR_SIZE 19
   8 #define MIDR_REVISION_MASK      0xf
   9 #define MIDR_VARIANT_SHIFT      20
  10 #define MIDR_VARIANT_MASK       (0xf << MIDR_VARIANT_SHIFT)
  11
  12 char *get_cpuid_str(struct perf_pmu *pmu)
  13 {
  14         char *buf = NULL;
  15         char path[PATH_MAX];
  16         const char *sysfs = sysfs__mountpoint();
  17         int cpu;
  18         u64 midr = 0;
  19         struct cpu_map *cpus;
  20         FILE *file;
  21
  22         if (!sysfs || !pmu || !pmu->cpus)
  23                 return NULL;
  24
  25         buf = malloc(MIDR_SIZE);
  26         if (!buf)
  27                 return NULL;
  28
  29         /* read midr from list of cpus mapped to this pmu */
  30         cpus = cpu_map__get(pmu->cpus);
  31         for (cpu = 0; cpu < cpus->nr; cpu++) {
  32                 scnprintf(path, PATH_MAX, "%s/devices/system/cpu/cpu%d"MIDR,
  33                                 sysfs, cpus->map[cpu]);
  34
  35                 file = fopen(path, "r");
  36                 if (!file) {
  37                         pr_debug("fopen failed for file %s\n", path);
  38                         continue;
  39                 }
  40
  41                 if (!fgets(buf, MIDR_SIZE, file)) {
  42                         fclose(file);
  43                         continue;
  44                 }
  45                 fclose(file);
  46
  47                 /* Ignore/clear Variant[23:20] and
  48                  * Revision[3:0] of MIDR
  49                  */
  50                 midr = strtoul(buf, NULL, 16);
  51                 midr &= (~(MIDR_VARIANT_MASK | MIDR_REVISION_MASK));
  52                 scnprintf(buf, MIDR_SIZE, "0x%016lx", midr);
  53                 /* got midr break loop */
  54                 break;
  55         }
  56
  57         if (!midr) {
  58                 pr_err("failed to get cpuid string for PMU %s\n", pmu->name);
  59                 free(buf);
  60                 buf = NULL;
  61         }
  62
  63         cpu_map__put(cpus);
  64         return buf;
  65 }