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 #include <i386/perfmon.h>
  35
  36 /*
  37  * Kernel parameter determining whether threads are halted unconditionally
  38  * in the idle state.  This is the default behavior.
  39  * See machine_idle() for use.
  40  */
  41 int idlehalt = 1;
  42
  43
  44 static boolean_t
  45 cpu_is_hyperthreaded(void)
  46 {
  47         if  (cpuid_features() & CPUID_FEATURE_HTT)
  48                 return (cpuid_info()->cpuid_logical_per_package /
  49                         cpuid_info()->cpuid_cores_per_package) > 1;
  50         else
  51                 return FALSE;
  52 }
  53
  54 void *
  55 cpu_thread_alloc(int cpu)
  56 {
  57         int             core_base_cpu;
  58         int             ret;
  59         cpu_core_t      *core;
  60
  61         /*
  62          * Assume that all cpus have the same features.
  63          */
  64         if (cpu_is_hyperthreaded()) {
  65                 /*
  66                  * Get the cpu number of the base thread in the core.
  67                  */
  68                 core_base_cpu = cpu_to_core_cpu(cpu);
  69                 cpu_datap(cpu)->cpu_threadtype = CPU_THREADTYPE_INTEL_HTT;
  70         } else {
  71                 core_base_cpu = cpu;
  72                 cpu_datap(cpu)->cpu_threadtype = CPU_THREADTYPE_NONE;
  73         }
  74
  75         core = (cpu_core_t *) cpu_to_core(core_base_cpu);
  76         if (core == NULL) {
  77                 ret = kmem_alloc(kernel_map,
  78                                  (void *) &core, sizeof(cpu_core_t));
  79                 if (ret != KERN_SUCCESS)
  80                         panic("cpu_thread_alloc() kmem_alloc ret=%d\n", ret);
  81                 bzero((void *) core, sizeof(cpu_core_t));
  82
  83                 core->base_cpu = core_base_cpu;
  84
  85                 atomic_incl((long *) &machine_info.physical_cpu_max, 1);
  86
  87                 /* Allocate performance counter data area (if available) */
  88                 core->pmc = pmc_alloc();
  89         }
  90         atomic_incl((long *) &machine_info.logical_cpu_max, 1);
  91
  92         return (void *) core;
  93 }
  94
  95 void
  96 cpu_thread_init(void)
  97 {
  98         int             my_cpu = get_cpu_number();
  99         cpu_core_t      *my_core;
 100
 101         /*
 102          * If we're the boot processor we allocate the core structure here.
 103          * Otherwise the core has already been allocated (by the boot cpu).
 104          */
 105         if (my_cpu == master_cpu)
 106                 cpu_to_core(master_cpu) = cpu_thread_alloc(master_cpu);
 107
 108         my_core = cpu_core();
 109         if (my_core == NULL)
 110                 panic("cpu_thread_init() no core allocated for cpu %d", my_cpu);
 111
 112         atomic_incl((long *) &my_core->active_threads, 1);
 113         atomic_incl((long *) &machine_info.logical_cpu, 1);
 114         /* Note: cpus are started serially so this isn't as racey as it looks */
 115         if (my_core->num_threads == 0)
 116                 atomic_incl((long *) &machine_info.physical_cpu, 1);
 117         atomic_incl((long *) &my_core->num_threads, 1);
 118 }
 119
 120 /*
 121  * Called for a cpu to halt permanently
 122  * (as opposed to halting and expecting an interrupt to awaken it).
 123  */
 124 void
 125 cpu_thread_halt(void)
 126 {
 127         cpu_core_t      *my_core = cpu_core();
 128
 129         atomic_decl((long *) &machine_info.logical_cpu, 1);
 130         atomic_decl((long *) &my_core->active_threads, 1);
 131         if (atomic_decl_and_test((long *) &my_core->num_threads, 1))
 132                 atomic_decl((long *) &machine_info.physical_cpu, 1);
 133
 134         cpu_halt();
 135 }