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/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 (*pmc_hook)(struct thread *td, int function, void *arg) = NULL; 63 64/* Interrupt handler */ 65int (*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; 99TUNABLE_INT(PMC_SYSCTL_NAME_PREFIX "softevents", &pmc_softevents); 100SYSCTL_INT(_kern_hwpmc, OID_AUTO, softevents, CTLFLAG_TUN|CTLFLAG_RD, 101 &pmc_softevents, 0, "maximum number of soft events"); 102 103struct mtx pmc_softs_mtx; 104int pmc_softs_count; 105struct pmc_soft **pmc_softs; 106 107MTX_SYSINIT(pmc_soft_mtx, &pmc_softs_mtx, "pmc-softs", MTX_SPIN); 108 109static void 110pmc_init_sx(void) 111{ 112 sx_init_flags(&pmc_sx, "pmc-sx", SX_NOWITNESS); 113} 114 115SYSINIT(pmcsx, SI_SUB_LOCK, SI_ORDER_MIDDLE, pmc_init_sx, NULL); 116 117/* 118 * Helper functions. 119 */ 120 121/* 122 * A note on the CPU numbering scheme used by the hwpmc(4) driver. 123 * 124 * CPUs are denoted using numbers in the range 0..[pmc_cpu_max()-1]. 125 * CPUs could be numbered "sparsely" in this range; the predicate 126 * `pmc_cpu_is_present()' is used to test whether a given CPU is 127 * physically present. 128 * 129 * Further, a CPU that is physically present may be administratively 130 * disabled or otherwise unavailable for use by hwpmc(4). The 131 * `pmc_cpu_is_active()' predicate tests for CPU usability. An 132 * "active" CPU participates in thread scheduling and can field 133 * interrupts raised by PMC hardware. 134 * 135 * On systems with hyperthreaded CPUs, multiple logical CPUs may share 136 * PMC hardware resources. For such processors one logical CPU is 137 * denoted as the primary owner of the in-CPU PMC resources. The 138 * pmc_cpu_is_primary() predicate is used to distinguish this primary 139 * CPU from the others. 140 */ 141 142int 143pmc_cpu_is_active(int cpu) 144{ 145#ifdef SMP 146 return (pmc_cpu_is_present(cpu) && 147 !CPU_ISSET(cpu, &hlt_cpus_mask)); 148#else 149 return (1); 150#endif 151} 152 153/* Deprecated. */ 154int 155pmc_cpu_is_disabled(int cpu) 156{ 157 return (!pmc_cpu_is_active(cpu)); 158} 159 160int 161pmc_cpu_is_present(int cpu) 162{ 163#ifdef SMP 164 return (!CPU_ABSENT(cpu)); 165#else 166 return (1); 167#endif 168} 169 170int 171pmc_cpu_is_primary(int cpu) 172{ 173#ifdef SMP 174 return (!CPU_ISSET(cpu, &logical_cpus_mask)); 175#else 176 return (1); 177#endif 178} 179 180 181/* 182 * Return the maximum CPU number supported by the system. The return 183 * value is used for scaling internal data structures and for runtime 184 * checks. 185 */ 186unsigned int 187pmc_cpu_max(void) 188{ 189#ifdef SMP 190 return (mp_maxid+1); 191#else 192 return (1); 193#endif 194} 195 196#ifdef INVARIANTS 197 198/* 199 * Return the count of CPUs in the `active' state in the system. 200 */ 201int 202pmc_cpu_max_active(void) 203{ 204#ifdef SMP 205 /* 206 * When support for CPU hot-plugging is added to the kernel, 207 * this function would change to return the current number 208 * of "active" CPUs. 209 */ 210 return (mp_ncpus); 211#else 212 return (1); 213#endif 214} 215 216#endif 217 218/* 219 * Cleanup event name: 220 * - remove duplicate '_' 221 * - all uppercase 222 */ 223static void 224pmc_soft_namecleanup(char *name) 225{ 226 char *p, *q; 227 228 p = q = name; 229 230 for ( ; *p == '_' ; p++) 231 ; 232 for ( ; *p ; p++) { 233 if (*p == '_' && (*(p + 1) == '_' || *(p + 1) == '\0')) 234 continue; 235 else 236 *q++ = toupper(*p); 237 } 238 *q = '\0'; 239} 240 241void 242pmc_soft_ev_register(struct pmc_soft *ps) 243{ 244 static int warned = 0; 245 int n; 246 247 ps->ps_running = 0; 248 ps->ps_ev.pm_ev_code = 0; /* invalid */ 249 pmc_soft_namecleanup(ps->ps_ev.pm_ev_name); 250 251 mtx_lock_spin(&pmc_softs_mtx); 252 253 if (pmc_softs_count >= pmc_softevents) { 254 /* 255 * XXX Reusing events can enter a race condition where 256 * new allocated event will be used as an old one. 257 */ 258 for (n = 0; n < pmc_softevents; n++) 259 if (pmc_softs[n] == NULL) 260 break; 261 if (n == pmc_softevents) { 262 mtx_unlock_spin(&pmc_softs_mtx); 263 if (!warned) { 264 printf("hwpmc: too many soft events, " 265 "increase kern.hwpmc.softevents tunable\n"); 266 warned = 1; 267 } 268 return; 269 } 270 271 ps->ps_ev.pm_ev_code = PMC_EV_SOFT_FIRST + n; 272 pmc_softs[n] = ps; 273 } else { 274 ps->ps_ev.pm_ev_code = PMC_EV_SOFT_FIRST + pmc_softs_count; 275 pmc_softs[pmc_softs_count++] = ps; 276 } 277 278 mtx_unlock_spin(&pmc_softs_mtx); 279} 280 281void 282pmc_soft_ev_deregister(struct pmc_soft *ps) 283{ 284 285 KASSERT(ps != NULL, ("pmc_soft_deregister: called with NULL")); 286 287 mtx_lock_spin(&pmc_softs_mtx); 288 289 if (ps->ps_ev.pm_ev_code != 0 && 290 (ps->ps_ev.pm_ev_code - PMC_EV_SOFT_FIRST) < pmc_softevents) { 291 KASSERT(ps->ps_ev.pm_ev_code >= PMC_EV_SOFT_FIRST && 292 ps->ps_ev.pm_ev_code <= PMC_EV_SOFT_LAST, 293 ("pmc_soft_deregister: invalid event value")); 294 pmc_softs[ps->ps_ev.pm_ev_code - PMC_EV_SOFT_FIRST] = NULL; 295 } 296 297 mtx_unlock_spin(&pmc_softs_mtx); 298} 299 300struct pmc_soft * 301pmc_soft_ev_acquire(enum pmc_event ev) 302{ 303 struct pmc_soft *ps; 304 305 if (ev == 0 || (ev - PMC_EV_SOFT_FIRST) >= pmc_softevents) 306 return NULL; 307 308 KASSERT(ev >= PMC_EV_SOFT_FIRST && 309 ev <= PMC_EV_SOFT_LAST, 310 ("event out of range")); 311 312 mtx_lock_spin(&pmc_softs_mtx); 313 314 ps = pmc_softs[ev - PMC_EV_SOFT_FIRST]; 315 if (ps == NULL) 316 mtx_unlock_spin(&pmc_softs_mtx); 317 318 return ps; 319} 320 321void 322pmc_soft_ev_release(struct pmc_soft *ps) 323{ 324 325 mtx_unlock_spin(&pmc_softs_mtx); 326} 327 328/* 329 * Initialise hwpmc. 330 */ 331static void 332init_hwpmc(void *dummy __unused) 333{ 334 if (pmc_softevents <= 0 || 335 pmc_softevents > PMC_EV_DYN_COUNT) { 336 (void) printf("hwpmc: tunable \"softevents\"=%d out of " 337 "range.\n", pmc_softevents); 338 pmc_softevents = PMC_EV_DYN_COUNT; 339 } 340 pmc_softs = malloc(pmc_softevents * sizeof(struct pmc_soft *), M_PMCHOOKS, M_NOWAIT|M_ZERO); 341 KASSERT(pmc_softs != NULL, ("cannot allocate soft events table")); 342} 343 344SYSINIT(hwpmc, SI_SUB_KDTRACE, SI_ORDER_FIRST, init_hwpmc, NULL); 345 346