osfmk/i386/cpu_number.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * @OSF_COPYRIGHT@
  24  */
  25 /*
  26  * Mach Operating System
  27  * Copyright (c) 1991,1990 Carnegie Mellon University
  28  * All Rights Reserved.
  29  *
  30  * Permission to use, copy, modify and distribute this software and its
  31  * documentation is hereby granted, provided that both the copyright
  32  * notice and this permission notice appear in all copies of the
  33  * software, derivative works or modified versions, and any portions
  34  * thereof, and that both notices appear in supporting documentation.
  35  *
  36  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  37  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  38  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  39  *
  40  * Carnegie Mellon requests users of this software to return to
  41  *
  42  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  43  *  School of Computer Science
  44  *  Carnegie Mellon University
  45  *  Pittsburgh PA 15213-3890
  46  *
  47  * any improvements or extensions that they make and grant Carnegie Mellon
  48  * the rights to redistribute these changes.
  49  */
  50
  51 /*
  52  */
  53
  54 /*
  55  *      Machine-dependent definitions for cpu identification.
  56  *
  57  */
  58 #ifndef _I386_CPU_NUMBER_H_
  59 #define _I386_CPU_NUMBER_H_
  60
  61 #include <sys/appleapiopts.h>
  62
  63 #ifdef __APPLE_API_UNSTABLE
  64 extern int      cpu_number(void);
  65
  66 #ifdef MACH_KERNEL_PRIVATE
  67
  68 #include <platforms.h>
  69 #include <cpus.h>
  70
  71 #include <mp_v1_1.h>
  72
  73 #if     MP_V1_1
  74 #include <i386/apic.h>
  75 #include <i386/asm.h>
  76
  77 extern int lapic_id;
  78
  79 extern __inline__ int cpu_number(void)
  80 {
  81         register int cpu;
  82
  83         __asm__ volatile ("movl " CC_SYM_PREFIX "lapic_id, %0\n"
  84                           "     movl 0(%0), %0\n"
  85                           "     shrl %1, %0\n"
  86                           "     andl %2, %0"
  87                     : "=r" (cpu)
  88                     : "i" (LAPIC_ID_SHIFT), "i" (LAPIC_ID_MASK));
  89
  90         return(cpu);
  91 }
  92 #else   /* MP_V1_1 */
  93 /*
  94  * At least one corollary cpu type does not have local memory at all.
  95  * The only way I found to store the cpu number was in some 386/486
  96  * system register. cr3 has bits 0, 1, 2 and 5, 6, 7, 8, 9, 10, 11
  97  * available. Right now we use 0, 1 and 2. So we are limited to 8 cpus.
  98  * For more cpus, we could use bits 5 - 11 with a shift.
  99  *
 100  * Even for other machines, like COMPAQ this is much faster the inb/outb
 101  * 4 cycles instead of 10 to 30.
 102  */
 103 #if     defined(__GNUC__)
 104 #if     NCPUS   > 8
 105 #error  cpu_number() definition only works for #cpus <= 8
 106 #else
 107
 108 extern __inline__ int cpu_number(void)
 109 {
 110         register int cpu;
 111
 112         __asm__ volatile ("movl %%cr3, %0\n"
 113                 "       andl $0x7, %0"
 114                     : "=r" (cpu));
 115         return(cpu);
 116 }
 117 #endif
 118 #endif  /* defined(__GNUC__) */
 119
 120 #endif  /* MP_V1_1 */
 121
 122 #endif  /* MACH_KERNEL_PRIVATE */
 123
 124 #endif  /* __APPLE_API_UNSTABLE */
 125
 126 #endif  /* _I386_CPU_NUMBER_H_ */