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#include <linux/kernel.h>
#include <linux/bits.h>
#include <linux/bitfield.h>
#include <stdio.h>
#include <stdlib.h>
#include <perf/cpumap.h>
#include <api/fs/fs.h>
#include <errno.h>
#include "debug.h"
#include "header.h"
#define MIDR "/regs/identification/midr_el1"
#define MIDR_SIZE 19
#define MIDR_REVISION_MASK GENMASK(3, 0)
#define MIDR_VARIANT_MASK GENMASK(23, 20)
static int _get_cpuid(char *buf, size_t sz, struct perf_cpu_map *cpus)
{
const char *sysfs = sysfs__mountpoint();
struct perf_cpu cpu;
int idx, ret = EINVAL;
if (!sysfs || sz < MIDR_SIZE)
return EINVAL;
perf_cpu_map__for_each_cpu(cpu, idx, cpus) {
char path[PATH_MAX];
FILE *file;
scnprintf(path, PATH_MAX, "%s/devices/system/cpu/cpu%d" MIDR,
sysfs, cpu.cpu);
file = fopen(path, "r");
if (!file) {
pr_debug("fopen failed for file %s\n", path);
continue;
}
if (!fgets(buf, MIDR_SIZE, file)) {
fclose(file);
continue;
}
fclose(file);
/* got midr break loop */
ret = 0;
break;
}
return ret;
}
int get_cpuid(char *buf, size_t sz)
{
struct perf_cpu_map *cpus = perf_cpu_map__new_online_cpus();
int ret;
if (!cpus)
return EINVAL;
ret = _get_cpuid(buf, sz, cpus);
perf_cpu_map__put(cpus);
return ret;
}
char *get_cpuid_str(struct perf_pmu *pmu)
{
char *buf = NULL;
int res;
if (!pmu || !pmu->cpus)
return NULL;
buf = malloc(MIDR_SIZE);
if (!buf)
return NULL;
/* read midr from list of cpus mapped to this pmu */
res = _get_cpuid(buf, MIDR_SIZE, pmu->cpus);
if (res) {
pr_err("failed to get cpuid string for PMU %s\n", pmu->name);
free(buf);
buf = NULL;
}
return buf;
}
/*
* Return 0 if idstr is a higher or equal to version of the same part as
* mapcpuid. Therefore, if mapcpuid has 0 for revision and variant then any
* version of idstr will match as long as it's the same CPU type.
*
* Return 1 if the CPU type is different or the version of idstr is lower.
*/
int strcmp_cpuid_str(const char *mapcpuid, const char *idstr)
{
u64 map_id = strtoull(mapcpuid, NULL, 16);
char map_id_variant = FIELD_GET(MIDR_VARIANT_MASK, map_id);
char map_id_revision = FIELD_GET(MIDR_REVISION_MASK, map_id);
u64 id = strtoull(idstr, NULL, 16);
char id_variant = FIELD_GET(MIDR_VARIANT_MASK, id);
char id_revision = FIELD_GET(MIDR_REVISION_MASK, id);
u64 id_fields = ~(MIDR_VARIANT_MASK | MIDR_REVISION_MASK);
/* Compare without version first */
if ((map_id & id_fields) != (id & id_fields))
return 1;
/*
* ID matches, now compare version.
*
* Arm revisions (like r0p0) are compared here like two digit semver
* values eg. 1.3 < 2.0 < 2.1 < 2.2.
*
* r = high value = 'Variant' field in MIDR
* p = low value = 'Revision' field in MIDR
*
*/
if (id_variant > map_id_variant)
return 0;
if (id_variant == map_id_variant && id_revision >= map_id_revision)
return 0;
/*
* variant is less than mapfile variant or variants are the same but
* the revision doesn't match. Return no match.
*/
return 1;
}
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