osfmk/ppc/commpage/commpage.c

   1 /*
   2  * Copyright (c) 2003 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25
  26 /*
  27  *  This is a simplifed version of the commpage support from 10.3.
  28  *  The supported feature is the tuning of _cpu_capabilities.
  29  *  There is no shared page for user processes.
  30  */
  31
  32 #include <mach/mach_types.h>
  33 #include <mach/machine.h>
  34 #include <ppc/exception.h>
  35 #include <ppc/machine_routines.h>
  36 #include <machine/cpu_capabilities.h>
  37 #include <machine/commpage.h>
  38
  39 int             _cpu_capabilities = 0;                  // define the capability vector
  40
  41 /* Determine number of CPUs on this system.  We cannot rely on
  42  * machine_info.max_cpus this early in the boot.
  43  */
  44 static int
  45 commpage_cpus( void )
  46 {
  47     int         cpus;
  48
  49     cpus = ml_get_max_cpus();                   // NB: this call can block
  50
  51     if (cpus == 0)
  52         panic("commpage cpus==0");
  53     if (cpus > 0xFF)
  54         cpus = 0xFF;
  55
  56     return      cpus;
  57 }
  58
  59
  60 /* Initialize kernel version of _cpu_capabilities vector (used by KEXTs.) */
  61
  62 static void
  63 commpage_init_cpu_capabilities( void )
  64 {
  65     struct per_proc_info *pp;
  66     procFeatures        *pfp;
  67     int cpus;
  68     int available;
  69
  70     pp = per_proc_info;                                 // use CPU 0's per-proc
  71     pfp = &pp->pf;                                              // point to features in per-proc
  72     available = pfp->Available;
  73
  74     // If AltiVec is disabled make sure it is not reported as available.
  75     if ((available & pfAltivec) == 0) {
  76         _cpu_capabilities &= ~kHasAltivec;
  77     }
  78
  79     if (_cpu_capabilities & kDcbaAvailable) {           // if this processor has DCBA, time it...
  80         _cpu_capabilities |= commpage_time_dcba();      // ...and set kDcbaRecomended if it helps.
  81     }
  82
  83     cpus = commpage_cpus();                             // how many CPUs do we have
  84     if (cpus == 1) _cpu_capabilities |= kUP;
  85     _cpu_capabilities |= (cpus << kNumCPUsShift);
  86 }
  87
  88
  89 /* Fill in commpage: called once, during kernel initialization, from the
  90  * startup thread before user-mode code is running.
  91  * See the top of this file for a list of what you have to do to add
  92  * a new routine to the commpage.
  93  */
  94 void
  95 commpage_populate( void )
  96 {
  97     commpage_init_cpu_capabilities();
  98 }