1 /*- 2 * Copyright (c) 2003-2008 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 /* 88 * A note on the CPU numbering scheme used by the hwpmc(4) driver. 89 * 90 * CPUs are denoted using numbers in the range 0..[pmc_cpu_max()-1]. 91 * CPUs could be numbered "sparsely" in this range; the predicate 92 * `pmc_cpu_is_present()' is used to test whether a given CPU is 93 * physically present. 94 * 95 * Further, a CPU that is physically present may be administratively 96 * disabled or otherwise unavailable for use by hwpmc(4). The 97 * `pmc_cpu_is_active()' predicate tests for CPU usability. An 98 * "active" CPU participates in thread scheduling and can field 99 * interrupts raised by PMC hardware. 100 * 101 * On systems with hyperthreaded CPUs, multiple logical CPUs may share 102 * PMC hardware resources. For such processors one logical CPU is 103 * denoted as the primary owner of the in-CPU PMC resources. The 104 * pmc_cpu_is_primary() predicate is used to distinguish this primary 105 * CPU from the others. 106 */ 107 108 int 109 pmc_cpu_is_active(int cpu) 110 { 111 #ifdef SMP 112 return (pmc_cpu_is_present(cpu) && 113 (hlt_cpus_mask & (1 << cpu)) == 0); 114 #else 115 return (1); 116 #endif 117 } 118 119 /* Deprecated. */ 120 int 121 pmc_cpu_is_disabled(int cpu) 122 { 123 return (!pmc_cpu_is_active(cpu)); 124 } 125 126 int 127 pmc_cpu_is_present(int cpu) 128 { 129 #ifdef SMP 130 return (!CPU_ABSENT(cpu)); 131 #else 132 return (1); 133 #endif 134 } 135 136 int 137 pmc_cpu_is_primary(int cpu) 138 { 139 #ifdef SMP 140 return ((logical_cpus_mask & (1 << cpu)) == 0); 141 #else 142 return (1); 143 #endif 144 } 145 146 147 /* 148 * Return the maximum CPU number supported by the system. The return 149 * value is used for scaling internal data structures and for runtime 150 * checks. 151 */ 152 unsigned int 153 pmc_cpu_max(void) 154 { 155 #ifdef SMP 156 return (mp_maxid+1); 157 #else 158 return (1); 159 #endif 160 } 161 162 #ifdef INVARIANTS 163 164 /* 165 * Return the count of CPUs in the `active' state in the system. 166 */ 167 int 168 pmc_cpu_max_active(void) 169 { 170 #ifdef SMP 171 /* 172 * When support for CPU hot-plugging is added to the kernel, 173 * this function would change to return the current number 174 * of "active" CPUs. 175 */ 176 return (mp_ncpus); 177 #else 178 return (1); 179 #endif 180 } 181 182 #endif 183