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 #elif defined(__arm__) || defined (__arm64__)
  58 #       include <arm/cpu_internal.h>
  59 #else
  60 // fall back on declaring it extern.  The linker will sort us out.
  61 extern unsigned int real_ncpus;
  62 #endif
  63
  64 // Mask for supported options
  65 #define T_CHUD_BIND_OPT_MASK (-1UL)
  66
  67 #if 0
  68 #pragma mark **** thread binding ****
  69 #endif
  70
  71 /*
  72  * This method will bind a given thread to the requested CPU starting at the
  73  * next time quantum.  If the thread is the current thread, this method will
  74  * force a thread_block().  The result is that if you call this method on the
  75  * current thread, you will be on the requested CPU when this method returns.
  76  */
  77 __private_extern__ kern_return_t
  78 chudxnu_bind_thread(thread_t thread, int cpu, __unused int options)
  79 {
  80     processor_t proc = NULL;
  81
  82         if(cpu < 0 || (unsigned int)cpu >= real_ncpus) // sanity check
  83                 return KERN_FAILURE;
  84
  85         // temporary restriction until after phase 2 of the scheduler
  86         if(thread != current_thread())
  87                 return KERN_FAILURE;
  88
  89         proc = cpu_to_processor(cpu);
  90
  91         /*
  92          * Potentially racey, but mainly to prevent bind to shutdown
  93          * processor.
  94          */
  95         if(proc && !(proc->state == PROCESSOR_OFF_LINE) &&
  96                         !(proc->state == PROCESSOR_SHUTDOWN)) {
  97
  98                 thread_bind(proc);
  99
 100                 /*
 101                  * If we're trying to bind the current thread, and
 102                  * we're not on the target cpu, and not at interrupt
 103                  * context, block the current thread to force a
 104                  * reschedule on the target CPU.
 105                  */
 106                 if(thread == current_thread() &&
 107                         !ml_at_interrupt_context() && cpu_number() != cpu) {
 108                         (void)thread_block(THREAD_CONTINUE_NULL);
 109                 }
 110                 return KERN_SUCCESS;
 111         }
 112     return KERN_FAILURE;
 113 }
 114
 115 __private_extern__ kern_return_t
 116 chudxnu_unbind_thread(thread_t thread, __unused int options)
 117 {
 118         if(thread == current_thread())
 119                 thread_bind(PROCESSOR_NULL);
 120     return KERN_SUCCESS;
 121 }