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SubjectRe: [PATCH] perf tools: Add arm64 version of get_cpuid()
Date
On 13/12/2019 13:54, John Garry wrote:

Hi Arnaldo,

Do we need some reviews on this? Or was it missed/still catching up?

Cheers,
John

> Add an arm64 version of get_cpuid(), which is used for various annotation
> and headers - for example, I now get the CPUID in "perf report --header",
> as shown in this snippet:
>
> # hostname : ubuntu
> # os release : 5.5.0-rc1-dirty
> # perf version : 5.5.rc1.gbf8a13dc9851
> # arch : aarch64
> # nrcpus online : 96
> # nrcpus avail : 96
> # cpuid : 0x00000000480fd010
>
> Since much of the code to read the MIDR is already in get_cpuid_str(),
> factor out this code.
>
> Signed-off-by: John Garry <john.garry@huawei.com>
>
> diff --git a/tools/perf/arch/arm64/util/header.c b/tools/perf/arch/arm64/util/header.c
> index a32e4b72a98f..d730666ab95d 100644
> --- a/tools/perf/arch/arm64/util/header.c
> +++ b/tools/perf/arch/arm64/util/header.c
> @@ -1,8 +1,10 @@
> #include <stdio.h>
> #include <stdlib.h>
> #include <perf/cpumap.h>
> +#include <util/cpumap.h>
> #include <internal/cpumap.h>
> #include <api/fs/fs.h>
> +#include <errno.h>
> #include "debug.h"
> #include "header.h"
>
> @@ -12,26 +14,21 @@
> #define MIDR_VARIANT_SHIFT 20
> #define MIDR_VARIANT_MASK (0xf << MIDR_VARIANT_SHIFT)
>
> -char *get_cpuid_str(struct perf_pmu *pmu)
> +static int _get_cpuid(char *buf, size_t sz, struct perf_cpu_map *cpus)
> {
> - char *buf = NULL;
> - char path[PATH_MAX];
> const char *sysfs = sysfs__mountpoint();
> - int cpu;
> u64 midr = 0;
> - struct perf_cpu_map *cpus;
> - FILE *file;
> + int cpu;
>
> - if (!sysfs || !pmu || !pmu->cpus)
> - return NULL;
> + if (!sysfs || sz < MIDR_SIZE)
> + return EINVAL;
>
> - buf = malloc(MIDR_SIZE);
> - if (!buf)
> - return NULL;
> + cpus = perf_cpu_map__get(cpus);
>
> - /* read midr from list of cpus mapped to this pmu */
> - cpus = perf_cpu_map__get(pmu->cpus);
> for (cpu = 0; cpu < perf_cpu_map__nr(cpus); cpu++) {
> + char path[PATH_MAX];
> + FILE *file;
> +
> scnprintf(path, PATH_MAX, "%s/devices/system/cpu/cpu%d"MIDR,
> sysfs, cpus->map[cpu]);
>
> @@ -57,12 +54,48 @@ char *get_cpuid_str(struct perf_pmu *pmu)
> break;
> }
>
> - if (!midr) {
> + perf_cpu_map__put(cpus);
> +
> + if (!midr)
> + return EINVAL;
> +
> + return 0;
> +}
> +
> +int get_cpuid(char *buf, size_t sz)
> +{
> + struct perf_cpu_map *cpus = perf_cpu_map__new(NULL);
> + 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;
> }
>
> - perf_cpu_map__put(cpus);
> return buf;
> }
>

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