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  1. /*
  2.  * Copyright (C) 2001-2004 Jakub Jermar
  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.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. #ifndef __CPUID_H__
  30. #define __CPUID_H__
  31.  
  32. #include <arch/types.h>
  33.  
  34. struct cpu_info {
  35.     __u32 cpuid_eax;
  36.     __u32 cpuid_ebx;
  37.     __u32 cpuid_ecx;
  38.     __u32 cpuid_edx;
  39. } __attribute__ ((packed));
  40.  
  41. static inline __u32 has_cpuid(void)
  42. {
  43.     __u32 val, ret;
  44.    
  45.     __asm__ volatile (
  46.         "pushf\n"               /* read flags */
  47.         "popl %0\n"
  48.         "movl %0, %1\n"
  49.        
  50.         "btcl $21, %1\n"        /* swap the ID bit */
  51.        
  52.         "pushl %1\n"            /* propagate the change into flags */
  53.         "popf\n"
  54.         "pushf\n"
  55.         "popl %1\n"
  56.        
  57.         "andl $(1 << 21), %0\n" /* interrested only in ID bit */
  58.         "andl $(1 << 21), %1\n"
  59.         "xorl %1, %0\n"
  60.         : "=r" (ret), "=r" (val)
  61.     );
  62.    
  63.     return ret;
  64. }
  65.  
  66. static inline void cpuid(__u32 cmd, struct cpu_info *info)
  67. {
  68.     __asm__ volatile (
  69.         "movl %4, %%eax\n"
  70.         "cpuid\n"
  71.        
  72.         "movl %%eax, %0\n"
  73.         "movl %%ebx, %1\n"
  74.         "movl %%ecx, %2\n"
  75.         "movl %%edx, %3\n"
  76.         : "=m" (info->cpuid_eax), "=m" (info->cpuid_ebx), "=m" (info->cpuid_ecx), "=m" (info->cpuid_edx)
  77.         : "m" (cmd)
  78.         : "eax", "ebx", "ecx", "edx"
  79.     );
  80. }
  81.  
  82. #endif
  83.