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  * 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 #include <vm/vm_kern.h>
  23 #include <mach/machine.h>
  24 #include <i386/cpu_threads.h>
  25 #include <i386/cpuid.h>
  26 #include <i386/machine_cpu.h>
  27 #include <i386/lock.h>
  28
  29 /*
  30  * Kernel parameter determining whether threads are halted unconditionally
  31  * in the idle state.  This is the default behavior.
  32  * See machine_idle() for use.
  33  */
  34 int idlehalt = 1;
  35
  36 void
  37 cpu_thread_init(void)
  38 {
  39         int             my_cpu = get_cpu_number();
  40         int             my_core_base_cpu;
  41         int             ret;
  42         cpu_core_t      *my_core;
  43
  44         /* Have we initialized already for this cpu? */
  45         if (cpu_core())
  46                 return;
  47
  48         if (cpuid_features() & CPUID_FEATURE_HTT) {
  49                 /*
  50                  * Get the cpu number of the base thread in the core.
  51                  */
  52                 my_core_base_cpu = cpu_to_core_cpu(my_cpu);
  53                 current_cpu_datap()->cpu_threadtype = CPU_THREADTYPE_INTEL_HTT;
  54         } else {
  55                 my_core_base_cpu = my_cpu;
  56                 current_cpu_datap()->cpu_threadtype = CPU_THREADTYPE_NONE;
  57         }
  58
  59         /*
  60          * Allocate the base cpu_core struct if none exists.
  61          * Since we could be racing with other threads in the same core,
  62          * this needs care without using locks. We allocate a new core
  63          * structure and assign it atomically, freeing it if we lost the race.
  64          */
  65         my_core = (cpu_core_t *) cpu_to_core(my_core_base_cpu);
  66         if (my_core == NULL) {
  67                 cpu_core_t      *new_core;
  68
  69                 ret = kmem_alloc(kernel_map,
  70                                  (void *) &new_core, sizeof(cpu_core_t));
  71                 if (ret != KERN_SUCCESS)
  72                         panic("cpu_thread_init() kmem_alloc ret=%d\n", ret);
  73                 bzero((void *) new_core, sizeof(cpu_core_t));
  74                 new_core->base_cpu = my_core_base_cpu;
  75                 if (atomic_cmpxchg((uint32_t *) &cpu_to_core(my_core_base_cpu),
  76                                     0, (uint32_t) new_core)) {
  77                         atomic_incl((long *) &machine_info.physical_cpu, 1);
  78                         atomic_incl((long *) &machine_info.physical_cpu_max, 1);
  79                 } else {
  80                         kmem_free(kernel_map,
  81                                   (vm_offset_t)new_core, sizeof(cpu_core_t));
  82                 }
  83                 my_core = (cpu_core_t *) cpu_to_core(my_core_base_cpu);
  84         }
  85
  86         cpu_to_core(my_cpu) = (struct cpu_core *) my_core;
  87
  88         atomic_incl((long *) &my_core->active_threads, 1);
  89         atomic_incl((long *) &my_core->num_threads, 1);
  90         atomic_incl((long *) &machine_info.logical_cpu, 1);
  91         atomic_incl((long *) &machine_info.logical_cpu_max, 1);
  92
  93 }
  94
  95 /*
  96  * Called for a cpu to halt permanently
  97  * (as opposed to halting and expecting an interrupt to awaken it).
  98  */
  99 void
 100 cpu_thread_halt(void)
 101 {
 102         cpu_core_t      *my_core = cpu_core();
 103
 104         /* Note: don't ever decrement the number of physical processors */
 105         atomic_decl((long *) &my_core->active_threads, 1);
 106         atomic_decl((long *) &my_core->num_threads, 1);
 107         atomic_decl((long *) &machine_info.logical_cpu, 1);
 108
 109         cpu_halt();
 110 }