osfmk/chud/chud_thread.c

   1 /*
   2  * Copyright (c) 2003-2009 Apple 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
  29 #include <mach/mach_types.h>
  30 #include <mach/task.h>
  31 #include <mach/thread_act.h>
  32
  33 #include <kern/kern_types.h>
  34 #include <kern/processor.h>
  35 #include <kern/thread.h>
  36 #include <kern/kalloc.h>
  37
  38 #include <chud/chud_xnu.h>
  39 #include <chud/chud_xnu_private.h>
  40 #include <chud/chud_thread.h>
  41
  42 #include <machine/machine_routines.h>
  43
  44 #include <libkern/OSAtomic.h>
  45
  46 #if KPC
  47 #include <kern/kpc.h>
  48 #endif
  49
  50 #if KPERF
  51 #include <kperf/kperf.h>
  52 #endif
  53
  54 // include the correct file to find real_ncpus
  55 #if defined(__i386__) || defined(__x86_64__)
  56 #       include <i386/mp.h>
  57 #else
  58 // fall back on declaring it extern.  The linker will sort us out.
  59 extern unsigned int real_ncpus;
  60 #endif
  61
  62 // Mask for supported options
  63 #define T_CHUD_BIND_OPT_MASK (-1UL)
  64
  65 #if 0
  66 #pragma mark **** thread binding ****
  67 #endif
  68
  69 /*
  70  * This method will bind a given thread to the requested CPU starting at the
  71  * next time quantum.  If the thread is the current thread, this method will
  72  * force a thread_block().  The result is that if you call this method on the
  73  * current thread, you will be on the requested CPU when this method returns.
  74  */
  75 __private_extern__ kern_return_t
  76 chudxnu_bind_thread(thread_t thread, int cpu, __unused int options)
  77 {
  78     processor_t proc = NULL;
  79
  80         if(cpu < 0 || (unsigned int)cpu >= real_ncpus) // sanity check
  81                 return KERN_FAILURE;
  82
  83         // temporary restriction until after phase 2 of the scheduler
  84         if(thread != current_thread())
  85                 return KERN_FAILURE;
  86
  87         proc = cpu_to_processor(cpu);
  88
  89         /*
  90          * Potentially racey, but mainly to prevent bind to shutdown
  91          * processor.
  92          */
  93         if(proc && !(proc->state == PROCESSOR_OFF_LINE) &&
  94                         !(proc->state == PROCESSOR_SHUTDOWN)) {
  95
  96                 thread_bind(proc);
  97
  98                 /*
  99                  * If we're trying to bind the current thread, and
 100                  * we're not on the target cpu, and not at interrupt
 101                  * context, block the current thread to force a
 102                  * reschedule on the target CPU.
 103                  */
 104                 if(thread == current_thread() &&
 105                         !ml_at_interrupt_context() && cpu_number() != cpu) {
 106                         (void)thread_block(THREAD_CONTINUE_NULL);
 107                 }
 108                 return KERN_SUCCESS;
 109         }
 110     return KERN_FAILURE;
 111 }
 112
 113 __private_extern__ kern_return_t
 114 chudxnu_unbind_thread(thread_t thread, __unused int options)
 115 {
 116         if(thread == current_thread())
 117                 thread_bind(PROCESSOR_NULL);
 118     return KERN_SUCCESS;
 119 }