osfmk/i386/cpu_threads.c

   1 /*
   2  * Copyright (c) 2003-2004 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_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. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 #include <vm/vm_kern.h>
  29 #include <mach/machine.h>
  30 #include <i386/cpu_threads.h>
  31 #include <i386/cpuid.h>
  32 #include <i386/machine_cpu.h>
  33 #include <i386/lock.h>
  34
  35 /*
  36  * Kernel parameter determining whether threads are halted unconditionally
  37  * in the idle state.  This is the default behavior.
  38  * See machine_idle() for use.
  39  */
  40 int idlehalt = 1;
  41
  42 void
  43 cpu_thread_init(void)
  44 {
  45         int             my_cpu = get_cpu_number();
  46         int             my_core_base_cpu;
  47         int             ret;
  48         cpu_core_t      *my_core;
  49
  50         /* Have we initialized already for this cpu? */
  51         if (cpu_core())
  52                 return;
  53
  54         if (cpuid_features() & CPUID_FEATURE_HTT) {
  55                 /*
  56                  * Get the cpu number of the base thread in the core.
  57                  */
  58                 my_core_base_cpu = cpu_to_core_cpu(my_cpu);
  59                 current_cpu_datap()->cpu_threadtype = CPU_THREADTYPE_INTEL_HTT;
  60         } else {
  61                 my_core_base_cpu = my_cpu;
  62                 current_cpu_datap()->cpu_threadtype = CPU_THREADTYPE_NONE;
  63         }
  64
  65         /*
  66          * Allocate the base cpu_core struct if none exists.
  67          * Since we could be racing with other threads in the same core,
  68          * this needs care without using locks. We allocate a new core
  69          * structure and assign it atomically, freeing it if we lost the race.
  70          */
  71         my_core = (cpu_core_t *) cpu_to_core(my_core_base_cpu);
  72         if (my_core == NULL) {
  73                 cpu_core_t      *new_core;
  74
  75                 ret = kmem_alloc(kernel_map,
  76                                  (void *) &new_core, sizeof(cpu_core_t));
  77                 if (ret != KERN_SUCCESS)
  78                         panic("cpu_thread_init() kmem_alloc ret=%d\n", ret);
  79                 bzero((void *) new_core, sizeof(cpu_core_t));
  80                 new_core->base_cpu = my_core_base_cpu;
  81                 if (atomic_cmpxchg((uint32_t *) &cpu_to_core(my_core_base_cpu),
  82                                     0, (uint32_t) new_core)) {
  83                         atomic_incl((long *) &machine_info.physical_cpu, 1);
  84                         atomic_incl((long *) &machine_info.physical_cpu_max, 1);
  85                 } else {
  86                         kmem_free(kernel_map,
  87                                   (vm_offset_t)new_core, sizeof(cpu_core_t));
  88                 }
  89                 my_core = (cpu_core_t *) cpu_to_core(my_core_base_cpu);
  90         }
  91
  92         cpu_to_core(my_cpu) = (struct cpu_core *) my_core;
  93
  94         atomic_incl((long *) &my_core->active_threads, 1);
  95         atomic_incl((long *) &my_core->num_threads, 1);
  96         atomic_incl((long *) &machine_info.logical_cpu, 1);
  97         atomic_incl((long *) &machine_info.logical_cpu_max, 1);
  98
  99 }
 100
 101 /*
 102  * Called for a cpu to halt permanently
 103  * (as opposed to halting and expecting an interrupt to awaken it).
 104  */
 105 void
 106 cpu_thread_halt(void)
 107 {
 108         cpu_core_t      *my_core = cpu_core();
 109
 110         /* Note: don't ever decrement the number of physical processors */
 111         atomic_decl((long *) &my_core->active_threads, 1);
 112         atomic_decl((long *) &my_core->num_threads, 1);
 113         atomic_decl((long *) &machine_info.logical_cpu, 1);
 114
 115         cpu_halt();
 116 }