osfmk/i386/cpu_threads.c

   1 /*
   2  * Copyright (c) 2003-2004 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 #include <vm/vm_kern.h>
  24 #include <mach/machine.h>
  25 #include <i386/cpu_threads.h>
  26 #include <i386/cpuid.h>
  27 #include <i386/machine_cpu.h>
  28 #include <i386/lock.h>
  29
  30 /*
  31  * Kernel parameter determining whether threads are halted unconditionally
  32  * in the idle state.  This is the default behavior.
  33  * See machine_idle() for use.
  34  */
  35 int idlehalt = 1;
  36
  37 void
  38 cpu_thread_init(void)
  39 {
  40         int             my_cpu = get_cpu_number();
  41         int             my_core_base_cpu;
  42         int             ret;
  43         cpu_core_t      *my_core;
  44
  45         /* Have we initialized already for this cpu? */
  46         if (cpu_core())
  47                 return;
  48
  49         if (cpuid_features() & CPUID_FEATURE_HTT) {
  50                 /*
  51                  * Get the cpu number of the base thread in the core.
  52                  */
  53                 my_core_base_cpu = cpu_to_core_cpu(my_cpu);
  54                 current_cpu_datap()->cpu_threadtype = CPU_THREADTYPE_INTEL_HTT;
  55         } else {
  56                 my_core_base_cpu = my_cpu;
  57                 current_cpu_datap()->cpu_threadtype = CPU_THREADTYPE_NONE;
  58         }
  59
  60         /*
  61          * Allocate the base cpu_core struct if none exists.
  62          * Since we could be racing with other threads in the same core,
  63          * this needs care without using locks. We allocate a new core
  64          * structure and assign it atomically, freeing it if we lost the race.
  65          */
  66         my_core = (cpu_core_t *) cpu_to_core(my_core_base_cpu);
  67         if (my_core == NULL) {
  68                 cpu_core_t      *new_core;
  69
  70                 ret = kmem_alloc(kernel_map,
  71                                  (void *) &new_core, sizeof(cpu_core_t));
  72                 if (ret != KERN_SUCCESS)
  73                         panic("cpu_thread_init() kmem_alloc ret=%d\n", ret);
  74                 bzero((void *) new_core, sizeof(cpu_core_t));
  75                 new_core->base_cpu = my_core_base_cpu;
  76                 if (atomic_cmpxchg((uint32_t *) &cpu_to_core(my_core_base_cpu),
  77                                     0, (uint32_t) new_core)) {
  78                         atomic_incl((long *) &machine_info.physical_cpu, 1);
  79                         atomic_incl((long *) &machine_info.physical_cpu_max, 1);
  80                 } else {
  81                         kmem_free(kernel_map,
  82                                   (vm_offset_t)new_core, sizeof(cpu_core_t));
  83                 }
  84                 my_core = (cpu_core_t *) cpu_to_core(my_core_base_cpu);
  85         }
  86
  87         cpu_to_core(my_cpu) = (struct cpu_core *) my_core;
  88
  89         atomic_incl((long *) &my_core->active_threads, 1);
  90         atomic_incl((long *) &my_core->num_threads, 1);
  91         atomic_incl((long *) &machine_info.logical_cpu, 1);
  92         atomic_incl((long *) &machine_info.logical_cpu_max, 1);
  93
  94 }
  95
  96 /*
  97  * Called for a cpu to halt permanently
  98  * (as opposed to halting and expecting an interrupt to awaken it).
  99  */
 100 void
 101 cpu_thread_halt(void)
 102 {
 103         cpu_core_t      *my_core = cpu_core();
 104
 105         /* Note: don't ever decrement the number of physical processors */
 106         atomic_decl((long *) &my_core->active_threads, 1);
 107         atomic_decl((long *) &my_core->num_threads, 1);
 108         atomic_decl((long *) &machine_info.logical_cpu, 1);
 109
 110         cpu_halt();
 111 }