sys/kern/kern_pmc.c

   1 /*-
   2  * Copyright (c) 2003-2007 Joseph Koshy
   3  * Copyright (c) 2007 The FreeBSD Foundation
   4  * All rights reserved.
   5  *
   6  * Portions of this software were developed by A. Joseph Koshy under
   7  * sponsorship from the FreeBSD Foundation and Google, Inc.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
  19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
  22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28  * SUCH DAMAGE.
  29  */
  30
  31 #include <sys/cdefs.h>
  32 __FBSDID("$FreeBSD$");
  33
  34 #include "opt_hwpmc_hooks.h"
  35
  36 #include <sys/types.h>
  37 #include <sys/pmc.h>
  38 #include <sys/pmckern.h>
  39 #include <sys/smp.h>
  40
  41 #ifdef  HWPMC_HOOKS
  42 #define PMC_KERNEL_VERSION      PMC_VERSION
  43 #else
  44 #define PMC_KERNEL_VERSION      0
  45 #endif
  46
  47 const int pmc_kernel_version = PMC_KERNEL_VERSION;
  48
  49 /* Hook variable. */
  50 int (*pmc_hook)(struct thread *td, int function, void *arg) = NULL;
  51
  52 /* Interrupt handler */
  53 int (*pmc_intr)(int cpu, struct trapframe *tf) = NULL;
  54
  55 /* Bitmask of CPUs requiring servicing at hardclock time */
  56 volatile cpumask_t pmc_cpumask;
  57
  58 /*
  59  * A global count of SS mode PMCs.  When non-zero, this means that
  60  * we have processes that are sampling the system as a whole.
  61  */
  62 volatile int pmc_ss_count;
  63
  64 /*
  65  * Since PMC(4) may not be loaded in the current kernel, the
  66  * convention followed is that a non-NULL value of 'pmc_hook' implies
  67  * the presence of this kernel module.
  68  *
  69  * This requires us to protect 'pmc_hook' with a
  70  * shared (sx) lock -- thus making the process of calling into PMC(4)
  71  * somewhat more expensive than a simple 'if' check and indirect call.
  72  */
  73 struct sx pmc_sx;
  74
  75 static void
  76 pmc_init_sx(void)
  77 {
  78         sx_init_flags(&pmc_sx, "pmc-sx", SX_NOWITNESS);
  79 }
  80
  81 SYSINIT(pmcsx, SI_SUB_LOCK, SI_ORDER_MIDDLE, pmc_init_sx, NULL);
  82
  83 /*
  84  * Helper functions
  85  */
  86
  87 int
  88 pmc_cpu_is_disabled(int cpu)
  89 {
  90 #ifdef  SMP
  91         return ((hlt_cpus_mask & (1 << cpu)) != 0);
  92 #else
  93         return 0;
  94 #endif
  95 }
  96
  97 int
  98 pmc_cpu_is_logical(int cpu)
  99 {
 100 #ifdef  SMP
 101         return ((logical_cpus_mask & (1 << cpu)) != 0);
 102 #else
 103         return 0;
 104 #endif
 105 }