// SPDX-License-Identifier: GPL-2.0
#include <sys/types.h>
#include <errno.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <regex.h>

#include "../../../util/debug.h"
#include "../../../util/header.h"
#include "cpuid.h"

void get_cpuid_0(char *vendor, unsigned int *lvl)
{
        unsigned int b, c, d;

        cpuid(0, 0, lvl, &b, &c, &d);
        strncpy(&vendor[0], (char *)(&b), 4);
        strncpy(&vendor[4], (char *)(&d), 4);
        strncpy(&vendor[8], (char *)(&c), 4);
        vendor[12] = '\0';
}

static int
__get_cpuid(char *buffer, size_t sz, const char *fmt)
{
        unsigned int a, b, c, d, lvl;
        int family = -1, model = -1, step = -1;
        int nb;
        char vendor[16];

        get_cpuid_0(vendor, &lvl);

        if (lvl >= 1) {
                cpuid(1, 0, &a, &b, &c, &d);

                family = (a >> 8) & 0xf;  /* bits 11 - 8 */
                model  = (a >> 4) & 0xf;  /* Bits  7 - 4 */
                step   = a & 0xf;

                /* extended family */
                if (family == 0xf)
                        family += (a >> 20) & 0xff;

                /* extended model */
                if (family >= 0x6)
                        model += ((a >> 16) & 0xf) << 4;
        }
        nb = scnprintf(buffer, sz, fmt, vendor, family, model, step);

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

int
get_cpuid(char *buffer, size_t sz, struct perf_cpu cpu __maybe_unused)
{
        return __get_cpuid(buffer, sz, "%s,%u,%u,%u$");
}

char *get_cpuid_str(struct perf_cpu cpu __maybe_unused)
{
        char *buf = malloc(128);

        if (buf && __get_cpuid(buf, 128, "%s-%u-%X-%X$") < 0) {
                free(buf);
                return NULL;
        }
        return buf;
}

/* Full CPUID format for x86 is vendor-family-model-stepping */
static bool is_full_cpuid(const char *id)
{
        const char *tmp = id;
        int count = 0;

        while ((tmp = strchr(tmp, '-')) != NULL) {
                count++;
                tmp++;
        }

        if (count == 3)
                return true;

        return false;
}

int strcmp_cpuid_str(const char *mapcpuid, const char *id)
{
        regex_t re;
        regmatch_t pmatch[1];
        int match;
        bool full_mapcpuid = is_full_cpuid(mapcpuid);
        bool full_cpuid = is_full_cpuid(id);

        /*
         * Full CPUID format is required to identify a platform.
         * Error out if the cpuid string is incomplete.
         */
        if (full_mapcpuid && !full_cpuid) {
                pr_info("Invalid CPUID %s. Full CPUID is required, "
                        "vendor-family-model-stepping\n", id);
                return 1;
        }

        if (regcomp(&re, mapcpuid, REG_EXTENDED) != 0) {
                /* Warn unable to generate match particular string. */
                pr_info("Invalid regular expression %s\n", mapcpuid);
                return 1;
        }

        match = !regexec(&re, id, 1, pmatch, 0);
        regfree(&re);
        if (match) {
                size_t match_len = (pmatch[0].rm_eo - pmatch[0].rm_so);
                size_t cpuid_len;

                /* If the full CPUID format isn't required,
                 * ignoring the stepping.
                 */
                if (!full_mapcpuid && full_cpuid)
                        cpuid_len = strrchr(id, '-') - id;
                else
                        cpuid_len = strlen(id);

                /* Verify the entire string matched. */
                if (match_len == cpuid_len)
                        return 0;
        }

        return 1;
}