osfmk/i386/cpu_threads.c

   1 /*
   2  * Copyright (c) 2003-2004 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_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
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30 #include <vm/vm_kern.h>
  31 #include <mach/machine.h>
  32 #include <i386/cpu_threads.h>
  33 #include <i386/cpuid.h>
  34 #include <i386/machine_cpu.h>
  35 #include <i386/lock.h>
  36
  37 /*
  38  * Kernel parameter determining whether threads are halted unconditionally
  39  * in the idle state.  This is the default behavior.
  40  * See machine_idle() for use.
  41  */
  42 int idlehalt = 1;
  43
  44 void
  45 cpu_thread_init(void)
  46 {
  47         int             my_cpu = get_cpu_number();
  48         int             my_core_base_cpu;
  49         int             ret;
  50         cpu_core_t      *my_core;
  51
  52         /* Have we initialized already for this cpu? */
  53         if (cpu_core())
  54                 return;
  55
  56         if (cpuid_features() & CPUID_FEATURE_HTT) {
  57                 /*
  58                  * Get the cpu number of the base thread in the core.
  59                  */
  60                 my_core_base_cpu = cpu_to_core_cpu(my_cpu);
  61                 current_cpu_datap()->cpu_threadtype = CPU_THREADTYPE_INTEL_HTT;
  62         } else {
  63                 my_core_base_cpu = my_cpu;
  64                 current_cpu_datap()->cpu_threadtype = CPU_THREADTYPE_NONE;
  65         }
  66
  67         /*
  68          * Allocate the base cpu_core struct if none exists.
  69          * Since we could be racing with other threads in the same core,
  70          * this needs care without using locks. We allocate a new core
  71          * structure and assign it atomically, freeing it if we lost the race.
  72          */
  73         my_core = (cpu_core_t *) cpu_to_core(my_core_base_cpu);
  74         if (my_core == NULL) {
  75                 cpu_core_t      *new_core;
  76
  77                 ret = kmem_alloc(kernel_map,
  78                                  (void *) &new_core, sizeof(cpu_core_t));
  79                 if (ret != KERN_SUCCESS)
  80                         panic("cpu_thread_init() kmem_alloc ret=%d\n", ret);
  81                 bzero((void *) new_core, sizeof(cpu_core_t));
  82                 new_core->base_cpu = my_core_base_cpu;
  83                 if (atomic_cmpxchg((uint32_t *) &cpu_to_core(my_core_base_cpu),
  84                                     0, (uint32_t) new_core)) {
  85                         atomic_incl((long *) &machine_info.physical_cpu, 1);
  86                         atomic_incl((long *) &machine_info.physical_cpu_max, 1);
  87                 } else {
  88                         kmem_free(kernel_map,
  89                                   (vm_offset_t)new_core, sizeof(cpu_core_t));
  90                 }
  91                 my_core = (cpu_core_t *) cpu_to_core(my_core_base_cpu);
  92         }
  93
  94         cpu_to_core(my_cpu) = (struct cpu_core *) my_core;
  95
  96         atomic_incl((long *) &my_core->active_threads, 1);
  97         atomic_incl((long *) &my_core->num_threads, 1);
  98         atomic_incl((long *) &machine_info.logical_cpu, 1);
  99         atomic_incl((long *) &machine_info.logical_cpu_max, 1);
 100
 101 }
 102
 103 /*
 104  * Called for a cpu to halt permanently
 105  * (as opposed to halting and expecting an interrupt to awaken it).
 106  */
 107 void
 108 cpu_thread_halt(void)
 109 {
 110         cpu_core_t      *my_core = cpu_core();
 111
 112         /* Note: don't ever decrement the number of physical processors */
 113         atomic_decl((long *) &my_core->active_threads, 1);
 114         atomic_decl((long *) &my_core->num_threads, 1);
 115         atomic_decl((long *) &machine_info.logical_cpu, 1);
 116
 117         cpu_halt();
 118 }