LXR linux/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
  12char *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}
  66