/*      $OpenBSD: cpuprobe.c,v 1.3 2022/07/07 00:56:46 daniel Exp $     */

/*
 * Copyright (c) 2004 Tom Cosgrove <tom.cosgrove@arches-consulting.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <machine/psl.h>
#include <machine/specialreg.h>

#include "libsa.h"

int amd64_supported;
static int cpu_family, cpu_model, cpu_stepping;
static int psl_check;
static u_int32_t feature_ecx, feature_edx, feature_amd;
static char cpu_brandstr[48];           /* Includes term NUL byte */
static char cpu_vendor[13];             /* 12 chars plus NUL term */

/*
 * cpuid instruction.  request in eax, result in eax, ebx, ecx, edx.
 * requires caller to provide u_int32_t regs[4] array.
 */
u_int32_t
cpuid(u_int32_t eax, u_int32_t *regs)
{
        __asm volatile(
            "cpuid\n\t"
            "movl       %%eax, 0(%2)\n\t"
            "movl       %%ebx, 4(%2)\n\t"
            "movl       %%ecx, 8(%2)\n\t"
            "movl       %%edx, 12(%2)\n\t"
            : "=a" (eax)
            : "0" (eax), "S" (regs)
            : "bx", "cx", "dx");

        return eax;
}

void
cpuprobe(void)
{
        u_int32_t cpuid_max, extended_max;
        u_int32_t regs[4];

        /*
         * The following is a simple check to see if cpuid is supported.
         * We try to toggle bit 21 (PSL_ID) in eflags.  If it works, then
         * cpuid is supported.  If not, there's no cpuid, and we don't
         * try it (don't want /boot to get an invalid opcode exception).
         */
        __asm volatile(
            "pushfl\n\t"
            "popl       %2\n\t"
            "xorl       %2, %0\n\t"
            "pushl      %0\n\t"
            "popfl\n\t"
            "pushfl\n\t"
            "popl       %0\n\t"
            "xorl       %2, %0\n\t"             /* If %2 == %0, no cpuid */
            : "=r" (psl_check)
            : "0" (PSL_ID), "r" (0)
            : "cc");

        if (psl_check == PSL_ID) {                      /* cpuid supported */
                cpuid_max = cpuid(0, regs);             /* Highest std call */

                bcopy(&regs[1], cpu_vendor, sizeof(regs[1]));
                bcopy(&regs[3], cpu_vendor + 4, sizeof(regs[3]));
                bcopy(&regs[2], cpu_vendor + 8, sizeof(regs[2]));
                cpu_vendor[sizeof(cpu_vendor) - 1] = '\0';

                if (cpuid_max >= 1) {
                        u_int32_t id;

                        id = cpuid(1, regs);            /* Get basic info */
                        cpu_stepping = id & 0x000000f;
                        cpu_model = (id >> 4) & 0x0000000f;
                        cpu_family = (id >> 8) & 0x0000000f;

                        feature_ecx = regs[2];
                        feature_edx = regs[3];
                }

                extended_max = cpuid(0x80000000, regs); /* Highest ext  */

                if (extended_max >= 0x80000001) {
                        cpuid(0x80000001, regs);
                        feature_amd = regs[3];
                        if (feature_amd & CPUID_LONG)
                                amd64_supported = 1;
                }

                cpu_brandstr[0] = '\0';
                if (extended_max >= 0x80000004) {
                        u_int32_t brand_ints[12];

                        cpuid(0x80000002, brand_ints);
                        cpuid(0x80000003, brand_ints + 4);
                        cpuid(0x80000004, brand_ints + 8);

                        bcopy(brand_ints, cpu_brandstr,
                            sizeof(cpu_brandstr) - 1);

                        cpu_brandstr[sizeof(cpu_brandstr) - 1] = '\0';
                }
        }

        printf("%s", amd64_supported ? " amd64" : " i386");
}

void
dump_cpuinfo(void)
{
        printf("\"%s\", family %d, model %d, step %d\n",
            cpu_vendor, cpu_family, cpu_model, cpu_stepping);

        if (*cpu_brandstr)
                printf("%s\n", cpu_brandstr);

        printf("features: ecx 0x%x, edx 0x%x, amd 0x%x\n",
            feature_ecx, feature_edx, feature_amd);

        printf("psl_check: 0x%x\n", psl_check);
}