1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Performance event support for s390x - CPU-measurement Counter Facility 4 * 5 * Copyright IBM Corp. 2012, 2019 6 * Author(s): Hendrik Brueckner <brueckner@linux.ibm.com> 7 */ 8 #define KMSG_COMPONENT "cpum_cf" 9 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 10 11 #include <linux/kernel.h> 12 #include <linux/kernel_stat.h> 13 #include <linux/percpu.h> 14 #include <linux/notifier.h> 15 #include <linux/init.h> 16 #include <linux/export.h> 17 #include <asm/cpu_mcf.h> 18 19 static enum cpumf_ctr_set get_counter_set(u64 event) 20 { 21 int set = CPUMF_CTR_SET_MAX; 22 23 if (event < 32) 24 set = CPUMF_CTR_SET_BASIC; 25 else if (event < 64) 26 set = CPUMF_CTR_SET_USER; 27 else if (event < 128) 28 set = CPUMF_CTR_SET_CRYPTO; 29 else if (event < 288) 30 set = CPUMF_CTR_SET_EXT; 31 else if (event >= 448 && event < 496) 32 set = CPUMF_CTR_SET_MT_DIAG; 33 34 return set; 35 } 36 37 static int validate_ctr_version(const struct hw_perf_event *hwc) 38 { 39 struct cpu_cf_events *cpuhw; 40 int err = 0; 41 u16 mtdiag_ctl; 42 43 cpuhw = &get_cpu_var(cpu_cf_events); 44 45 /* check required version for counter sets */ 46 switch (hwc->config_base) { 47 case CPUMF_CTR_SET_BASIC: 48 case CPUMF_CTR_SET_USER: 49 if (cpuhw->info.cfvn < 1) 50 err = -EOPNOTSUPP; 51 break; 52 case CPUMF_CTR_SET_CRYPTO: 53 if ((cpuhw->info.csvn >= 1 && cpuhw->info.csvn <= 5 && 54 hwc->config > 79) || 55 (cpuhw->info.csvn >= 6 && hwc->config > 83)) 56 err = -EOPNOTSUPP; 57 break; 58 case CPUMF_CTR_SET_EXT: 59 if (cpuhw->info.csvn < 1) 60 err = -EOPNOTSUPP; 61 if ((cpuhw->info.csvn == 1 && hwc->config > 159) || 62 (cpuhw->info.csvn == 2 && hwc->config > 175) || 63 (cpuhw->info.csvn >= 3 && cpuhw->info.csvn <= 5 64 && hwc->config > 255) || 65 (cpuhw->info.csvn >= 6 && hwc->config > 287)) 66 err = -EOPNOTSUPP; 67 break; 68 case CPUMF_CTR_SET_MT_DIAG: 69 if (cpuhw->info.csvn <= 3) 70 err = -EOPNOTSUPP; 71 /* 72 * MT-diagnostic counters are read-only. The counter set 73 * is automatically enabled and activated on all CPUs with 74 * multithreading (SMT). Deactivation of multithreading 75 * also disables the counter set. State changes are ignored 76 * by lcctl(). Because Linux controls SMT enablement through 77 * a kernel parameter only, the counter set is either disabled 78 * or enabled and active. 79 * 80 * Thus, the counters can only be used if SMT is on and the 81 * counter set is enabled and active. 82 */ 83 mtdiag_ctl = cpumf_ctr_ctl[CPUMF_CTR_SET_MT_DIAG]; 84 if (!((cpuhw->info.auth_ctl & mtdiag_ctl) && 85 (cpuhw->info.enable_ctl & mtdiag_ctl) && 86 (cpuhw->info.act_ctl & mtdiag_ctl))) 87 err = -EOPNOTSUPP; 88 break; 89 } 90 91 put_cpu_var(cpu_cf_events); 92 return err; 93 } 94 95 static int validate_ctr_auth(const struct hw_perf_event *hwc) 96 { 97 struct cpu_cf_events *cpuhw; 98 u64 ctrs_state; 99 int err = 0; 100 101 cpuhw = &get_cpu_var(cpu_cf_events); 102 103 /* Check authorization for cpu counter sets. 104 * If the particular CPU counter set is not authorized, 105 * return with -ENOENT in order to fall back to other 106 * PMUs that might suffice the event request. 107 */ 108 ctrs_state = cpumf_ctr_ctl[hwc->config_base]; 109 if (!(ctrs_state & cpuhw->info.auth_ctl)) 110 err = -ENOENT; 111 112 put_cpu_var(cpu_cf_events); 113 return err; 114 } 115 116 /* 117 * Change the CPUMF state to active. 118 * Enable and activate the CPU-counter sets according 119 * to the per-cpu control state. 120 */ 121 static void cpumf_pmu_enable(struct pmu *pmu) 122 { 123 struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events); 124 int err; 125 126 if (cpuhw->flags & PMU_F_ENABLED) 127 return; 128 129 err = lcctl(cpuhw->state); 130 if (err) { 131 pr_err("Enabling the performance measuring unit " 132 "failed with rc=%x\n", err); 133 return; 134 } 135 136 cpuhw->flags |= PMU_F_ENABLED; 137 } 138 139 /* 140 * Change the CPUMF state to inactive. 141 * Disable and enable (inactive) the CPU-counter sets according 142 * to the per-cpu control state. 143 */ 144 static void cpumf_pmu_disable(struct pmu *pmu) 145 { 146 struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events); 147 int err; 148 u64 inactive; 149 150 if (!(cpuhw->flags & PMU_F_ENABLED)) 151 return; 152 153 inactive = cpuhw->state & ~((1 << CPUMF_LCCTL_ENABLE_SHIFT) - 1); 154 err = lcctl(inactive); 155 if (err) { 156 pr_err("Disabling the performance measuring unit " 157 "failed with rc=%x\n", err); 158 return; 159 } 160 161 cpuhw->flags &= ~PMU_F_ENABLED; 162 } 163 164 165 /* Number of perf events counting hardware events */ 166 static atomic_t num_events = ATOMIC_INIT(0); 167 /* Used to avoid races in calling reserve/release_cpumf_hardware */ 168 static DEFINE_MUTEX(pmc_reserve_mutex); 169 170 /* Release the PMU if event is the last perf event */ 171 static void hw_perf_event_destroy(struct perf_event *event) 172 { 173 if (!atomic_add_unless(&num_events, -1, 1)) { 174 mutex_lock(&pmc_reserve_mutex); 175 if (atomic_dec_return(&num_events) == 0) 176 __kernel_cpumcf_end(); 177 mutex_unlock(&pmc_reserve_mutex); 178 } 179 } 180 181 /* CPUMF <-> perf event mappings for kernel+userspace (basic set) */ 182 static const int cpumf_generic_events_basic[] = { 183 [PERF_COUNT_HW_CPU_CYCLES] = 0, 184 [PERF_COUNT_HW_INSTRUCTIONS] = 1, 185 [PERF_COUNT_HW_CACHE_REFERENCES] = -1, 186 [PERF_COUNT_HW_CACHE_MISSES] = -1, 187 [PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = -1, 188 [PERF_COUNT_HW_BRANCH_MISSES] = -1, 189 [PERF_COUNT_HW_BUS_CYCLES] = -1, 190 }; 191 /* CPUMF <-> perf event mappings for userspace (problem-state set) */ 192 static const int cpumf_generic_events_user[] = { 193 [PERF_COUNT_HW_CPU_CYCLES] = 32, 194 [PERF_COUNT_HW_INSTRUCTIONS] = 33, 195 [PERF_COUNT_HW_CACHE_REFERENCES] = -1, 196 [PERF_COUNT_HW_CACHE_MISSES] = -1, 197 [PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = -1, 198 [PERF_COUNT_HW_BRANCH_MISSES] = -1, 199 [PERF_COUNT_HW_BUS_CYCLES] = -1, 200 }; 201 202 static int __hw_perf_event_init(struct perf_event *event, unsigned int type) 203 { 204 struct perf_event_attr *attr = &event->attr; 205 struct hw_perf_event *hwc = &event->hw; 206 enum cpumf_ctr_set set; 207 int err = 0; 208 u64 ev; 209 210 switch (type) { 211 case PERF_TYPE_RAW: 212 /* Raw events are used to access counters directly, 213 * hence do not permit excludes */ 214 if (attr->exclude_kernel || attr->exclude_user || 215 attr->exclude_hv) 216 return -EOPNOTSUPP; 217 ev = attr->config; 218 break; 219 220 case PERF_TYPE_HARDWARE: 221 if (is_sampling_event(event)) /* No sampling support */ 222 return -ENOENT; 223 ev = attr->config; 224 /* Count user space (problem-state) only */ 225 if (!attr->exclude_user && attr->exclude_kernel) { 226 if (ev >= ARRAY_SIZE(cpumf_generic_events_user)) 227 return -EOPNOTSUPP; 228 ev = cpumf_generic_events_user[ev]; 229 230 /* No support for kernel space counters only */ 231 } else if (!attr->exclude_kernel && attr->exclude_user) { 232 return -EOPNOTSUPP; 233 234 /* Count user and kernel space */ 235 } else { 236 if (ev >= ARRAY_SIZE(cpumf_generic_events_basic)) 237 return -EOPNOTSUPP; 238 ev = cpumf_generic_events_basic[ev]; 239 } 240 break; 241 242 default: 243 return -ENOENT; 244 } 245 246 if (ev == -1) 247 return -ENOENT; 248 249 if (ev > PERF_CPUM_CF_MAX_CTR) 250 return -ENOENT; 251 252 /* Obtain the counter set to which the specified counter belongs */ 253 set = get_counter_set(ev); 254 switch (set) { 255 case CPUMF_CTR_SET_BASIC: 256 case CPUMF_CTR_SET_USER: 257 case CPUMF_CTR_SET_CRYPTO: 258 case CPUMF_CTR_SET_EXT: 259 case CPUMF_CTR_SET_MT_DIAG: 260 /* 261 * Use the hardware perf event structure to store the 262 * counter number in the 'config' member and the counter 263 * set number in the 'config_base'. The counter set number 264 * is then later used to enable/disable the counter(s). 265 */ 266 hwc->config = ev; 267 hwc->config_base = set; 268 break; 269 case CPUMF_CTR_SET_MAX: 270 /* The counter could not be associated to a counter set */ 271 return -EINVAL; 272 }; 273 274 /* Initialize for using the CPU-measurement counter facility */ 275 if (!atomic_inc_not_zero(&num_events)) { 276 mutex_lock(&pmc_reserve_mutex); 277 if (atomic_read(&num_events) == 0 && __kernel_cpumcf_begin()) 278 err = -EBUSY; 279 else 280 atomic_inc(&num_events); 281 mutex_unlock(&pmc_reserve_mutex); 282 } 283 if (err) 284 return err; 285 event->destroy = hw_perf_event_destroy; 286 287 /* Finally, validate version and authorization of the counter set */ 288 err = validate_ctr_auth(hwc); 289 if (!err) 290 err = validate_ctr_version(hwc); 291 292 return err; 293 } 294 295 static int cpumf_pmu_event_init(struct perf_event *event) 296 { 297 unsigned int type = event->attr.type; 298 int err; 299 300 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_RAW) 301 err = __hw_perf_event_init(event, type); 302 else if (event->pmu->type == type) 303 /* Registered as unknown PMU */ 304 err = __hw_perf_event_init(event, PERF_TYPE_RAW); 305 else 306 return -ENOENT; 307 308 if (unlikely(err) && event->destroy) 309 event->destroy(event); 310 311 return err; 312 } 313 314 static int hw_perf_event_reset(struct perf_event *event) 315 { 316 u64 prev, new; 317 int err; 318 319 do { 320 prev = local64_read(&event->hw.prev_count); 321 err = ecctr(event->hw.config, &new); 322 if (err) { 323 if (err != 3) 324 break; 325 /* The counter is not (yet) available. This 326 * might happen if the counter set to which 327 * this counter belongs is in the disabled 328 * state. 329 */ 330 new = 0; 331 } 332 } while (local64_cmpxchg(&event->hw.prev_count, prev, new) != prev); 333 334 return err; 335 } 336 337 static void hw_perf_event_update(struct perf_event *event) 338 { 339 u64 prev, new, delta; 340 int err; 341 342 do { 343 prev = local64_read(&event->hw.prev_count); 344 err = ecctr(event->hw.config, &new); 345 if (err) 346 return; 347 } while (local64_cmpxchg(&event->hw.prev_count, prev, new) != prev); 348 349 delta = (prev <= new) ? new - prev 350 : (-1ULL - prev) + new + 1; /* overflow */ 351 local64_add(delta, &event->count); 352 } 353 354 static void cpumf_pmu_read(struct perf_event *event) 355 { 356 if (event->hw.state & PERF_HES_STOPPED) 357 return; 358 359 hw_perf_event_update(event); 360 } 361 362 static void cpumf_pmu_start(struct perf_event *event, int flags) 363 { 364 struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events); 365 struct hw_perf_event *hwc = &event->hw; 366 367 if (WARN_ON_ONCE(!(hwc->state & PERF_HES_STOPPED))) 368 return; 369 370 if (WARN_ON_ONCE(hwc->config == -1)) 371 return; 372 373 if (flags & PERF_EF_RELOAD) 374 WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE)); 375 376 hwc->state = 0; 377 378 /* (Re-)enable and activate the counter set */ 379 ctr_set_enable(&cpuhw->state, hwc->config_base); 380 ctr_set_start(&cpuhw->state, hwc->config_base); 381 382 /* The counter set to which this counter belongs can be already active. 383 * Because all counters in a set are active, the event->hw.prev_count 384 * needs to be synchronized. At this point, the counter set can be in 385 * the inactive or disabled state. 386 */ 387 hw_perf_event_reset(event); 388 389 /* increment refcount for this counter set */ 390 atomic_inc(&cpuhw->ctr_set[hwc->config_base]); 391 } 392 393 static void cpumf_pmu_stop(struct perf_event *event, int flags) 394 { 395 struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events); 396 struct hw_perf_event *hwc = &event->hw; 397 398 if (!(hwc->state & PERF_HES_STOPPED)) { 399 /* Decrement reference count for this counter set and if this 400 * is the last used counter in the set, clear activation 401 * control and set the counter set state to inactive. 402 */ 403 if (!atomic_dec_return(&cpuhw->ctr_set[hwc->config_base])) 404 ctr_set_stop(&cpuhw->state, hwc->config_base); 405 event->hw.state |= PERF_HES_STOPPED; 406 } 407 408 if ((flags & PERF_EF_UPDATE) && !(hwc->state & PERF_HES_UPTODATE)) { 409 hw_perf_event_update(event); 410 event->hw.state |= PERF_HES_UPTODATE; 411 } 412 } 413 414 static int cpumf_pmu_add(struct perf_event *event, int flags) 415 { 416 struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events); 417 418 /* Check authorization for the counter set to which this 419 * counter belongs. 420 * For group events transaction, the authorization check is 421 * done in cpumf_pmu_commit_txn(). 422 */ 423 if (!(cpuhw->txn_flags & PERF_PMU_TXN_ADD)) 424 if (validate_ctr_auth(&event->hw)) 425 return -ENOENT; 426 427 ctr_set_enable(&cpuhw->state, event->hw.config_base); 428 event->hw.state = PERF_HES_UPTODATE | PERF_HES_STOPPED; 429 430 if (flags & PERF_EF_START) 431 cpumf_pmu_start(event, PERF_EF_RELOAD); 432 433 perf_event_update_userpage(event); 434 435 return 0; 436 } 437 438 static void cpumf_pmu_del(struct perf_event *event, int flags) 439 { 440 struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events); 441 442 cpumf_pmu_stop(event, PERF_EF_UPDATE); 443 444 /* Check if any counter in the counter set is still used. If not used, 445 * change the counter set to the disabled state. This also clears the 446 * content of all counters in the set. 447 * 448 * When a new perf event has been added but not yet started, this can 449 * clear enable control and resets all counters in a set. Therefore, 450 * cpumf_pmu_start() always has to reenable a counter set. 451 */ 452 if (!atomic_read(&cpuhw->ctr_set[event->hw.config_base])) 453 ctr_set_disable(&cpuhw->state, event->hw.config_base); 454 455 perf_event_update_userpage(event); 456 } 457 458 /* 459 * Start group events scheduling transaction. 460 * Set flags to perform a single test at commit time. 461 * 462 * We only support PERF_PMU_TXN_ADD transactions. Save the 463 * transaction flags but otherwise ignore non-PERF_PMU_TXN_ADD 464 * transactions. 465 */ 466 static void cpumf_pmu_start_txn(struct pmu *pmu, unsigned int txn_flags) 467 { 468 struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events); 469 470 WARN_ON_ONCE(cpuhw->txn_flags); /* txn already in flight */ 471 472 cpuhw->txn_flags = txn_flags; 473 if (txn_flags & ~PERF_PMU_TXN_ADD) 474 return; 475 476 perf_pmu_disable(pmu); 477 cpuhw->tx_state = cpuhw->state; 478 } 479 480 /* 481 * Stop and cancel a group events scheduling tranctions. 482 * Assumes cpumf_pmu_del() is called for each successful added 483 * cpumf_pmu_add() during the transaction. 484 */ 485 static void cpumf_pmu_cancel_txn(struct pmu *pmu) 486 { 487 unsigned int txn_flags; 488 struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events); 489 490 WARN_ON_ONCE(!cpuhw->txn_flags); /* no txn in flight */ 491 492 txn_flags = cpuhw->txn_flags; 493 cpuhw->txn_flags = 0; 494 if (txn_flags & ~PERF_PMU_TXN_ADD) 495 return; 496 497 WARN_ON(cpuhw->tx_state != cpuhw->state); 498 499 perf_pmu_enable(pmu); 500 } 501 502 /* 503 * Commit the group events scheduling transaction. On success, the 504 * transaction is closed. On error, the transaction is kept open 505 * until cpumf_pmu_cancel_txn() is called. 506 */ 507 static int cpumf_pmu_commit_txn(struct pmu *pmu) 508 { 509 struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events); 510 u64 state; 511 512 WARN_ON_ONCE(!cpuhw->txn_flags); /* no txn in flight */ 513 514 if (cpuhw->txn_flags & ~PERF_PMU_TXN_ADD) { 515 cpuhw->txn_flags = 0; 516 return 0; 517 } 518 519 /* check if the updated state can be scheduled */ 520 state = cpuhw->state & ~((1 << CPUMF_LCCTL_ENABLE_SHIFT) - 1); 521 state >>= CPUMF_LCCTL_ENABLE_SHIFT; 522 if ((state & cpuhw->info.auth_ctl) != state) 523 return -ENOENT; 524 525 cpuhw->txn_flags = 0; 526 perf_pmu_enable(pmu); 527 return 0; 528 } 529 530 /* Performance monitoring unit for s390x */ 531 static struct pmu cpumf_pmu = { 532 .task_ctx_nr = perf_sw_context, 533 .capabilities = PERF_PMU_CAP_NO_INTERRUPT, 534 .pmu_enable = cpumf_pmu_enable, 535 .pmu_disable = cpumf_pmu_disable, 536 .event_init = cpumf_pmu_event_init, 537 .add = cpumf_pmu_add, 538 .del = cpumf_pmu_del, 539 .start = cpumf_pmu_start, 540 .stop = cpumf_pmu_stop, 541 .read = cpumf_pmu_read, 542 .start_txn = cpumf_pmu_start_txn, 543 .commit_txn = cpumf_pmu_commit_txn, 544 .cancel_txn = cpumf_pmu_cancel_txn, 545 }; 546 547 static int __init cpumf_pmu_init(void) 548 { 549 int rc; 550 551 if (!kernel_cpumcf_avail()) 552 return -ENODEV; 553 554 cpumf_pmu.attr_groups = cpumf_cf_event_group(); 555 rc = perf_pmu_register(&cpumf_pmu, "cpum_cf", -1); 556 if (rc) 557 pr_err("Registering the cpum_cf PMU failed with rc=%i\n", rc); 558 return rc; 559 } 560 subsys_initcall(cpumf_pmu_init); 561