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

   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
  15char *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}
  69