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: stable/11/sys/kern/kern_pmc.c 315285 2017-03-14 20:43:04Z mjg $"); 33 34#include "opt_hwpmc_hooks.h" 35 36#include <sys/types.h> 37#include <sys/ctype.h> 38#include <sys/param.h> 39#include <sys/malloc.h> 40#include <sys/kernel.h> 41#include <sys/lock.h> 42#include <sys/mutex.h> 43#include <sys/pmc.h> 44#include <sys/pmckern.h> 45#include <sys/smp.h> 46#include <sys/sysctl.h> 47#include <sys/systm.h> 48 49#ifdef HWPMC_HOOKS 50FEATURE(hwpmc_hooks, "Kernel support for HW PMC"); 51#define PMC_KERNEL_VERSION PMC_VERSION 52#else 53#define PMC_KERNEL_VERSION 0 54#endif 55 56MALLOC_DECLARE(M_PMCHOOKS); 57MALLOC_DEFINE(M_PMCHOOKS, "pmchooks", "Memory space for PMC hooks"); 58 59const int pmc_kernel_version = PMC_KERNEL_VERSION; 60 61/* Hook variable. */ 62int __read_mostly (*pmc_hook)(struct thread *td, int function, void *arg) = NULL; 63 64/* Interrupt handler */ 65int __read_mostly (*pmc_intr)(int cpu, struct trapframe *tf) = NULL; 66 67/* Bitmask of CPUs requiring servicing at hardclock time */ 68volatile cpuset_t pmc_cpumask; 69 70/* 71 * A global count of SS mode PMCs. When non-zero, this means that 72 * we have processes that are sampling the system as a whole. 73 */ 74volatile int pmc_ss_count; 75 76/* 77 * Since PMC(4) may not be loaded in the current kernel, the 78 * convention followed is that a non-NULL value of 'pmc_hook' implies 79 * the presence of this kernel module. 80 * 81 * This requires us to protect 'pmc_hook' with a 82 * shared (sx) lock -- thus making the process of calling into PMC(4) 83 * somewhat more expensive than a simple 'if' check and indirect call. 84 */ 85struct sx pmc_sx; 86 87/* 88 * PMC Soft per cpu trapframe. 89 */ 90struct trapframe pmc_tf[MAXCPU]; 91 92/* 93 * PMC Soft use a global table to store registered events. 94 */ 95 96SYSCTL_NODE(_kern, OID_AUTO, hwpmc, CTLFLAG_RW, 0, "HWPMC parameters"); 97 98static int pmc_softevents = 16; 99SYSCTL_INT(_kern_hwpmc, OID_AUTO, softevents, CTLFLAG_RDTUN, 100 &pmc_softevents, 0, "maximum number of soft events"); 101 102struct mtx pmc_softs_mtx; 103int pmc_softs_count; 104struct pmc_soft **pmc_softs; 105 106MTX_SYSINIT(pmc_soft_mtx, &pmc_softs_mtx, "pmc-softs", MTX_SPIN); 107 108static void 109pmc_init_sx(void) 110{ 111 sx_init_flags(&pmc_sx, "pmc-sx", SX_NOWITNESS); 112} 113 114SYSINIT(pmcsx, SI_SUB_LOCK, SI_ORDER_MIDDLE, pmc_init_sx, NULL); 115 116/* 117 * Helper functions. 118 */ 119 120/* 121 * A note on the CPU numbering scheme used by the hwpmc(4) driver. 122 * 123 * CPUs are denoted using numbers in the range 0..[pmc_cpu_max()-1]. 124 * CPUs could be numbered "sparsely" in this range; the predicate 125 * `pmc_cpu_is_present()' is used to test whether a given CPU is 126 * physically present. 127 * 128 * Further, a CPU that is physically present may be administratively 129 * disabled or otherwise unavailable for use by hwpmc(4). The 130 * `pmc_cpu_is_active()' predicate tests for CPU usability. An 131 * "active" CPU participates in thread scheduling and can field 132 * interrupts raised by PMC hardware. 133 * 134 * On systems with hyperthreaded CPUs, multiple logical CPUs may share 135 * PMC hardware resources. For such processors one logical CPU is 136 * denoted as the primary owner of the in-CPU PMC resources. The 137 * pmc_cpu_is_primary() predicate is used to distinguish this primary 138 * CPU from the others. 139 */ 140 141int 142pmc_cpu_is_active(int cpu) 143{ 144#ifdef SMP 145 return (pmc_cpu_is_present(cpu) && 146 !CPU_ISSET(cpu, &hlt_cpus_mask)); 147#else 148 return (1); 149#endif 150} 151 152/* Deprecated. */ 153int 154pmc_cpu_is_disabled(int cpu) 155{ 156 return (!pmc_cpu_is_active(cpu)); 157} 158 159int 160pmc_cpu_is_present(int cpu) 161{ 162#ifdef SMP 163 return (!CPU_ABSENT(cpu)); 164#else 165 return (1); 166#endif 167} 168 169int 170pmc_cpu_is_primary(int cpu) 171{ 172#ifdef SMP 173 return (!CPU_ISSET(cpu, &logical_cpus_mask)); 174#else 175 return (1); 176#endif 177} 178 179 180/* 181 * Return the maximum CPU number supported by the system. The return 182 * value is used for scaling internal data structures and for runtime 183 * checks. 184 */ 185unsigned int 186pmc_cpu_max(void) 187{ 188#ifdef SMP 189 return (mp_maxid+1); 190#else 191 return (1); 192#endif 193} 194 195#ifdef INVARIANTS 196 197/* 198 * Return the count of CPUs in the `active' state in the system. 199 */ 200int 201pmc_cpu_max_active(void) 202{ 203#ifdef SMP 204 /* 205 * When support for CPU hot-plugging is added to the kernel, 206 * this function would change to return the current number 207 * of "active" CPUs. 208 */ 209 return (mp_ncpus); 210#else 211 return (1); 212#endif 213} 214 215#endif 216 217/* 218 * Cleanup event name: 219 * - remove duplicate '_' 220 * - all uppercase 221 */ 222static void 223pmc_soft_namecleanup(char *name) 224{ 225 char *p, *q; 226 227 p = q = name; 228 229 for ( ; *p == '_' ; p++) 230 ; 231 for ( ; *p ; p++) { 232 if (*p == '_' && (*(p + 1) == '_' || *(p + 1) == '\0')) 233 continue; 234 else 235 *q++ = toupper(*p); 236 } 237 *q = '\0'; 238} 239 240void 241pmc_soft_ev_register(struct pmc_soft *ps) 242{ 243 static int warned = 0; 244 int n; 245 246 ps->ps_running = 0; 247 ps->ps_ev.pm_ev_code = 0; /* invalid */ 248 pmc_soft_namecleanup(ps->ps_ev.pm_ev_name); 249 250 mtx_lock_spin(&pmc_softs_mtx); 251 252 if (pmc_softs_count >= pmc_softevents) { 253 /* 254 * XXX Reusing events can enter a race condition where 255 * new allocated event will be used as an old one. 256 */ 257 for (n = 0; n < pmc_softevents; n++) 258 if (pmc_softs[n] == NULL) 259 break; 260 if (n == pmc_softevents) { 261 mtx_unlock_spin(&pmc_softs_mtx); 262 if (!warned) { 263 printf("hwpmc: too many soft events, " 264 "increase kern.hwpmc.softevents tunable\n"); 265 warned = 1; 266 } 267 return; 268 } 269 270 ps->ps_ev.pm_ev_code = PMC_EV_SOFT_FIRST + n; 271 pmc_softs[n] = ps; 272 } else { 273 ps->ps_ev.pm_ev_code = PMC_EV_SOFT_FIRST + pmc_softs_count; 274 pmc_softs[pmc_softs_count++] = ps; 275 } 276 277 mtx_unlock_spin(&pmc_softs_mtx); 278} 279 280void 281pmc_soft_ev_deregister(struct pmc_soft *ps) 282{ 283 284 KASSERT(ps != NULL, ("pmc_soft_deregister: called with NULL")); 285 286 mtx_lock_spin(&pmc_softs_mtx); 287 288 if (ps->ps_ev.pm_ev_code != 0 && 289 (ps->ps_ev.pm_ev_code - PMC_EV_SOFT_FIRST) < pmc_softevents) { 290 KASSERT(ps->ps_ev.pm_ev_code >= PMC_EV_SOFT_FIRST && 291 ps->ps_ev.pm_ev_code <= PMC_EV_SOFT_LAST, 292 ("pmc_soft_deregister: invalid event value")); 293 pmc_softs[ps->ps_ev.pm_ev_code - PMC_EV_SOFT_FIRST] = NULL; 294 } 295 296 mtx_unlock_spin(&pmc_softs_mtx); 297} 298 299struct pmc_soft * 300pmc_soft_ev_acquire(enum pmc_event ev) 301{ 302 struct pmc_soft *ps; 303 304 if (ev == 0 || (ev - PMC_EV_SOFT_FIRST) >= pmc_softevents) 305 return NULL; 306 307 KASSERT(ev >= PMC_EV_SOFT_FIRST && 308 ev <= PMC_EV_SOFT_LAST, 309 ("event out of range")); 310 311 mtx_lock_spin(&pmc_softs_mtx); 312 313 ps = pmc_softs[ev - PMC_EV_SOFT_FIRST]; 314 if (ps == NULL) 315 mtx_unlock_spin(&pmc_softs_mtx); 316 317 return ps; 318} 319 320void 321pmc_soft_ev_release(struct pmc_soft *ps) 322{ 323 324 mtx_unlock_spin(&pmc_softs_mtx); 325} 326 327/* 328 * Initialise hwpmc. 329 */ 330static void 331init_hwpmc(void *dummy __unused) 332{ 333 if (pmc_softevents <= 0 || 334 pmc_softevents > PMC_EV_DYN_COUNT) { 335 (void) printf("hwpmc: tunable \"softevents\"=%d out of " 336 "range.\n", pmc_softevents); 337 pmc_softevents = PMC_EV_DYN_COUNT; 338 } 339 pmc_softs = malloc(pmc_softevents * sizeof(struct pmc_soft *), M_PMCHOOKS, M_NOWAIT|M_ZERO); 340 KASSERT(pmc_softs != NULL, ("cannot allocate soft events table")); 341} 342 343SYSINIT(hwpmc, SI_SUB_KDTRACE, SI_ORDER_FIRST, init_hwpmc, NULL); 344 345