usr/src/boot/sys/boot/efi/loader/arch/amd64/bootinfo64.c

   1 /*-
   2  * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 #include <sys/cdefs.h>
  28 #include <stand.h>
  29 #include <machine/cpufunc.h>
  30 #include <machine/psl.h>
  31 #include <machine/specialreg.h>
  32
  33 /*
  34  * Check to see if this CPU supports long mode.
  35  */
  36 static int
  37 bi_checkcpu(void)
  38 {
  39     char *cpu_vendor;
  40     int vendor[3];
  41     u_long rflags;
  42     unsigned int regs[4];
  43
  44     /* Check for presence of "cpuid". */
  45     rflags = read_rflags();
  46     write_rflags(rflags ^ PSL_ID);
  47     if (!((rflags ^ read_rflags()) & PSL_ID))
  48         return (0);
  49
  50     /* Fetch the vendor string. */
  51     do_cpuid(0, regs);
  52     vendor[0] = regs[1];
  53     vendor[1] = regs[3];
  54     vendor[2] = regs[2];
  55     cpu_vendor = (char *)vendor;
  56
  57     /* Check for vendors that support AMD features. */
  58     if (strncmp(cpu_vendor, INTEL_VENDOR_ID, 12) != 0 &&
  59         strncmp(cpu_vendor, AMD_VENDOR_ID, 12) != 0 &&
  60         strncmp(cpu_vendor, CENTAUR_VENDOR_ID, 12) != 0)
  61         return (0);
  62
  63     /* Has to support AMD features. */
  64     do_cpuid(0x80000000, regs);
  65     if (!(regs[0] >= 0x80000001))
  66         return (0);
  67
  68     /* Check for long mode. */
  69     do_cpuid(0x80000001, regs);
  70     return (regs[3] & AMDID_LM);
  71 }
  72
  73 void
  74 bi_isadir(void)
  75 {
  76         if (bi_checkcpu())
  77                 setenv("ISADIR", "amd64", 1);
  78         else
  79                 setenv("ISADIR", "", 1);
  80 }