header.c

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// SPDX-License-Identifier: GPL-2.0
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <linux/stringify.h>
#include "header.h"
#include "util.h"

#define mfspr(rn)       ({unsigned long rval; \
             asm volatile("mfspr %0," __stringify(rn) \
                      : "=r" (rval)); rval; })

#define SPRN_PVR        0x11F   /* Processor Version Register */
#define PVR_VER(pvr)    (((pvr) >>  16) & 0xFFFF) /* Version field */
#define PVR_REV(pvr)    (((pvr) >>   0) & 0xFFFF) /* Revison field */

int
get_cpuid(char *buffer, size_t sz)
{
    unsigned long pvr;
    int nb;

    pvr = mfspr(SPRN_PVR);

    nb = scnprintf(buffer, sz, "%lu,%lu$", PVR_VER(pvr), PVR_REV(pvr));

    /* look for end marker to ensure the entire data fit */
    if (strchr(buffer, '$')) {
        buffer[nb-1] = '\0';
        return 0;
    }
    return -1;
}

char *
get_cpuid_str(struct perf_pmu *pmu __maybe_unused)
{
    char *bufp;

    if (asprintf(&bufp, "%.8lx", mfspr(SPRN_PVR)) < 0)
        bufp = NULL;

    return bufp;
}