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

DEFINITIONS

1. get_cpuid_str

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <perf/cpumap.h>
   4 #include <internal/cpumap.h>
   5 #include <api/fs/fs.h>
   6 #include "debug.h"
   7 #include "header.h"
   8 
   9 #define MIDR "/regs/identification/midr_el1"
  10 #define MIDR_SIZE 19
  11 #define MIDR_REVISION_MASK      0xf
  12 #define MIDR_VARIANT_SHIFT      20
  13 #define MIDR_VARIANT_MASK       (0xf << MIDR_VARIANT_SHIFT)
  14 
  15 char *get_cpuid_str(struct perf_pmu *pmu)
  16 {
  17         char *buf = NULL;
  18         char path[PATH_MAX];
  19         const char *sysfs = sysfs__mountpoint();
  20         int cpu;
  21         u64 midr = 0;
  22         struct perf_cpu_map *cpus;
  23         FILE *file;
  24 
  25         if (!sysfs || !pmu || !pmu->cpus)
  26                 return NULL;
  27 
  28         buf = malloc(MIDR_SIZE);
  29         if (!buf)
  30                 return NULL;
  31 
  32         /* read midr from list of cpus mapped to this pmu */
  33         cpus = perf_cpu_map__get(pmu->cpus);
  34         for (cpu = 0; cpu < perf_cpu_map__nr(cpus); cpu++) {
  35                 scnprintf(path, PATH_MAX, "%s/devices/system/cpu/cpu%d"MIDR,
  36                                 sysfs, cpus->map[cpu]);
  37 
  38                 file = fopen(path, "r");
  39                 if (!file) {
  40                         pr_debug("fopen failed for file %s\n", path);
  41                         continue;
  42                 }
  43 
  44                 if (!fgets(buf, MIDR_SIZE, file)) {
  45                         fclose(file);
  46                         continue;
  47                 }
  48                 fclose(file);
  49 
  50                 /* Ignore/clear Variant[23:20] and
  51                  * Revision[3:0] of MIDR
  52                  */
  53                 midr = strtoul(buf, NULL, 16);
  54                 midr &= (~(MIDR_VARIANT_MASK | MIDR_REVISION_MASK));
  55                 scnprintf(buf, MIDR_SIZE, "0x%016lx", midr);
  56                 /* got midr break loop */
  57                 break;
  58         }
  59 
  60         if (!midr) {
  61                 pr_err("failed to get cpuid string for PMU %s\n", pmu->name);
  62                 free(buf);
  63                 buf = NULL;
  64         }
  65 
  66         perf_cpu_map__put(cpus);
  67         return buf;
  68 }