1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Performance event support for the System z CPU-measurement Sampling Facility 4 * 5 * Copyright IBM Corp. 2013, 2018 6 * Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com> 7 */ 8 #define KMSG_COMPONENT "cpum_sf" 9 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 10 11 #include <linux/kernel.h> 12 #include <linux/kernel_stat.h> 13 #include <linux/perf_event.h> 14 #include <linux/percpu.h> 15 #include <linux/pid.h> 16 #include <linux/notifier.h> 17 #include <linux/export.h> 18 #include <linux/slab.h> 19 #include <linux/mm.h> 20 #include <linux/moduleparam.h> 21 #include <asm/cpu_mf.h> 22 #include <asm/irq.h> 23 #include <asm/debug.h> 24 #include <asm/timex.h> 25 26 /* Minimum number of sample-data-block-tables: 27 * At least one table is required for the sampling buffer structure. 28 * A single table contains up to 511 pointers to sample-data-blocks. 29 */ 30 #define CPUM_SF_MIN_SDBT 1 31 32 /* Number of sample-data-blocks per sample-data-block-table (SDBT): 33 * A table contains SDB pointers (8 bytes) and one table-link entry 34 * that points to the origin of the next SDBT. 35 */ 36 #define CPUM_SF_SDB_PER_TABLE ((PAGE_SIZE - 8) / 8) 37 38 /* Maximum page offset for an SDBT table-link entry: 39 * If this page offset is reached, a table-link entry to the next SDBT 40 * must be added. 41 */ 42 #define CPUM_SF_SDBT_TL_OFFSET (CPUM_SF_SDB_PER_TABLE * 8) 43 static inline int require_table_link(const void *sdbt) 44 { 45 return ((unsigned long) sdbt & ~PAGE_MASK) == CPUM_SF_SDBT_TL_OFFSET; 46 } 47 48 /* Minimum and maximum sampling buffer sizes: 49 * 50 * This number represents the maximum size of the sampling buffer taking 51 * the number of sample-data-block-tables into account. Note that these 52 * numbers apply to the basic-sampling function only. 53 * The maximum number of SDBs is increased by CPUM_SF_SDB_DIAG_FACTOR if 54 * the diagnostic-sampling function is active. 55 * 56 * Sampling buffer size Buffer characteristics 57 * --------------------------------------------------- 58 * 64KB == 16 pages (4KB per page) 59 * 1 page for SDB-tables 60 * 15 pages for SDBs 61 * 62 * 32MB == 8192 pages (4KB per page) 63 * 16 pages for SDB-tables 64 * 8176 pages for SDBs 65 */ 66 static unsigned long __read_mostly CPUM_SF_MIN_SDB = 15; 67 static unsigned long __read_mostly CPUM_SF_MAX_SDB = 8176; 68 static unsigned long __read_mostly CPUM_SF_SDB_DIAG_FACTOR = 1; 69 70 struct sf_buffer { 71 unsigned long *sdbt; /* Sample-data-block-table origin */ 72 /* buffer characteristics (required for buffer increments) */ 73 unsigned long num_sdb; /* Number of sample-data-blocks */ 74 unsigned long num_sdbt; /* Number of sample-data-block-tables */ 75 unsigned long *tail; /* last sample-data-block-table */ 76 }; 77 78 struct aux_buffer { 79 struct sf_buffer sfb; 80 unsigned long head; /* index of SDB of buffer head */ 81 unsigned long alert_mark; /* index of SDB of alert request position */ 82 unsigned long empty_mark; /* mark of SDB not marked full */ 83 unsigned long *sdb_index; /* SDB address for fast lookup */ 84 unsigned long *sdbt_index; /* SDBT address for fast lookup */ 85 }; 86 87 struct cpu_hw_sf { 88 /* CPU-measurement sampling information block */ 89 struct hws_qsi_info_block qsi; 90 /* CPU-measurement sampling control block */ 91 struct hws_lsctl_request_block lsctl; 92 struct sf_buffer sfb; /* Sampling buffer */ 93 unsigned int flags; /* Status flags */ 94 struct perf_event *event; /* Scheduled perf event */ 95 struct perf_output_handle handle; /* AUX buffer output handle */ 96 }; 97 static DEFINE_PER_CPU(struct cpu_hw_sf, cpu_hw_sf); 98 99 /* Debug feature */ 100 static debug_info_t *sfdbg; 101 102 /* 103 * sf_disable() - Switch off sampling facility 104 */ 105 static int sf_disable(void) 106 { 107 struct hws_lsctl_request_block sreq; 108 109 memset(&sreq, 0, sizeof(sreq)); 110 return lsctl(&sreq); 111 } 112 113 /* 114 * sf_buffer_available() - Check for an allocated sampling buffer 115 */ 116 static int sf_buffer_available(struct cpu_hw_sf *cpuhw) 117 { 118 return !!cpuhw->sfb.sdbt; 119 } 120 121 /* 122 * deallocate sampling facility buffer 123 */ 124 static void free_sampling_buffer(struct sf_buffer *sfb) 125 { 126 unsigned long *sdbt, *curr; 127 128 if (!sfb->sdbt) 129 return; 130 131 sdbt = sfb->sdbt; 132 curr = sdbt; 133 134 /* Free the SDBT after all SDBs are processed... */ 135 while (1) { 136 if (!*curr || !sdbt) 137 break; 138 139 /* Process table-link entries */ 140 if (is_link_entry(curr)) { 141 curr = get_next_sdbt(curr); 142 if (sdbt) 143 free_page((unsigned long) sdbt); 144 145 /* If the origin is reached, sampling buffer is freed */ 146 if (curr == sfb->sdbt) 147 break; 148 else 149 sdbt = curr; 150 } else { 151 /* Process SDB pointer */ 152 if (*curr) { 153 free_page(*curr); 154 curr++; 155 } 156 } 157 } 158 159 debug_sprintf_event(sfdbg, 5, 160 "free_sampling_buffer: freed sdbt=%p\n", sfb->sdbt); 161 memset(sfb, 0, sizeof(*sfb)); 162 } 163 164 static int alloc_sample_data_block(unsigned long *sdbt, gfp_t gfp_flags) 165 { 166 unsigned long sdb, *trailer; 167 168 /* Allocate and initialize sample-data-block */ 169 sdb = get_zeroed_page(gfp_flags); 170 if (!sdb) 171 return -ENOMEM; 172 trailer = trailer_entry_ptr(sdb); 173 *trailer = SDB_TE_ALERT_REQ_MASK; 174 175 /* Link SDB into the sample-data-block-table */ 176 *sdbt = sdb; 177 178 return 0; 179 } 180 181 /* 182 * realloc_sampling_buffer() - extend sampler memory 183 * 184 * Allocates new sample-data-blocks and adds them to the specified sampling 185 * buffer memory. 186 * 187 * Important: This modifies the sampling buffer and must be called when the 188 * sampling facility is disabled. 189 * 190 * Returns zero on success, non-zero otherwise. 191 */ 192 static int realloc_sampling_buffer(struct sf_buffer *sfb, 193 unsigned long num_sdb, gfp_t gfp_flags) 194 { 195 int i, rc; 196 unsigned long *new, *tail; 197 198 if (!sfb->sdbt || !sfb->tail) 199 return -EINVAL; 200 201 if (!is_link_entry(sfb->tail)) 202 return -EINVAL; 203 204 /* Append to the existing sampling buffer, overwriting the table-link 205 * register. 206 * The tail variables always points to the "tail" (last and table-link) 207 * entry in an SDB-table. 208 */ 209 tail = sfb->tail; 210 211 /* Do a sanity check whether the table-link entry points to 212 * the sampling buffer origin. 213 */ 214 if (sfb->sdbt != get_next_sdbt(tail)) { 215 debug_sprintf_event(sfdbg, 3, "realloc_sampling_buffer: " 216 "sampling buffer is not linked: origin=%p" 217 "tail=%p\n", 218 (void *) sfb->sdbt, (void *) tail); 219 return -EINVAL; 220 } 221 222 /* Allocate remaining SDBs */ 223 rc = 0; 224 for (i = 0; i < num_sdb; i++) { 225 /* Allocate a new SDB-table if it is full. */ 226 if (require_table_link(tail)) { 227 new = (unsigned long *) get_zeroed_page(gfp_flags); 228 if (!new) { 229 rc = -ENOMEM; 230 break; 231 } 232 sfb->num_sdbt++; 233 /* Link current page to tail of chain */ 234 *tail = (unsigned long)(void *) new + 1; 235 tail = new; 236 } 237 238 /* Allocate a new sample-data-block. 239 * If there is not enough memory, stop the realloc process 240 * and simply use what was allocated. If this is a temporary 241 * issue, a new realloc call (if required) might succeed. 242 */ 243 rc = alloc_sample_data_block(tail, gfp_flags); 244 if (rc) 245 break; 246 sfb->num_sdb++; 247 tail++; 248 } 249 250 /* Link sampling buffer to its origin */ 251 *tail = (unsigned long) sfb->sdbt + 1; 252 sfb->tail = tail; 253 254 debug_sprintf_event(sfdbg, 4, "realloc_sampling_buffer: new buffer" 255 " settings: sdbt=%lu sdb=%lu\n", 256 sfb->num_sdbt, sfb->num_sdb); 257 return rc; 258 } 259 260 /* 261 * allocate_sampling_buffer() - allocate sampler memory 262 * 263 * Allocates and initializes a sampling buffer structure using the 264 * specified number of sample-data-blocks (SDB). For each allocation, 265 * a 4K page is used. The number of sample-data-block-tables (SDBT) 266 * are calculated from SDBs. 267 * Also set the ALERT_REQ mask in each SDBs trailer. 268 * 269 * Returns zero on success, non-zero otherwise. 270 */ 271 static int alloc_sampling_buffer(struct sf_buffer *sfb, unsigned long num_sdb) 272 { 273 int rc; 274 275 if (sfb->sdbt) 276 return -EINVAL; 277 278 /* Allocate the sample-data-block-table origin */ 279 sfb->sdbt = (unsigned long *) get_zeroed_page(GFP_KERNEL); 280 if (!sfb->sdbt) 281 return -ENOMEM; 282 sfb->num_sdb = 0; 283 sfb->num_sdbt = 1; 284 285 /* Link the table origin to point to itself to prepare for 286 * realloc_sampling_buffer() invocation. 287 */ 288 sfb->tail = sfb->sdbt; 289 *sfb->tail = (unsigned long)(void *) sfb->sdbt + 1; 290 291 /* Allocate requested number of sample-data-blocks */ 292 rc = realloc_sampling_buffer(sfb, num_sdb, GFP_KERNEL); 293 if (rc) { 294 free_sampling_buffer(sfb); 295 debug_sprintf_event(sfdbg, 4, "alloc_sampling_buffer: " 296 "realloc_sampling_buffer failed with rc=%i\n", rc); 297 } else 298 debug_sprintf_event(sfdbg, 4, 299 "alloc_sampling_buffer: tear=%p dear=%p\n", 300 sfb->sdbt, (void *) *sfb->sdbt); 301 return rc; 302 } 303 304 static void sfb_set_limits(unsigned long min, unsigned long max) 305 { 306 struct hws_qsi_info_block si; 307 308 CPUM_SF_MIN_SDB = min; 309 CPUM_SF_MAX_SDB = max; 310 311 memset(&si, 0, sizeof(si)); 312 if (!qsi(&si)) 313 CPUM_SF_SDB_DIAG_FACTOR = DIV_ROUND_UP(si.dsdes, si.bsdes); 314 } 315 316 static unsigned long sfb_max_limit(struct hw_perf_event *hwc) 317 { 318 return SAMPL_DIAG_MODE(hwc) ? CPUM_SF_MAX_SDB * CPUM_SF_SDB_DIAG_FACTOR 319 : CPUM_SF_MAX_SDB; 320 } 321 322 static unsigned long sfb_pending_allocs(struct sf_buffer *sfb, 323 struct hw_perf_event *hwc) 324 { 325 if (!sfb->sdbt) 326 return SFB_ALLOC_REG(hwc); 327 if (SFB_ALLOC_REG(hwc) > sfb->num_sdb) 328 return SFB_ALLOC_REG(hwc) - sfb->num_sdb; 329 return 0; 330 } 331 332 static int sfb_has_pending_allocs(struct sf_buffer *sfb, 333 struct hw_perf_event *hwc) 334 { 335 return sfb_pending_allocs(sfb, hwc) > 0; 336 } 337 338 static void sfb_account_allocs(unsigned long num, struct hw_perf_event *hwc) 339 { 340 /* Limit the number of SDBs to not exceed the maximum */ 341 num = min_t(unsigned long, num, sfb_max_limit(hwc) - SFB_ALLOC_REG(hwc)); 342 if (num) 343 SFB_ALLOC_REG(hwc) += num; 344 } 345 346 static void sfb_init_allocs(unsigned long num, struct hw_perf_event *hwc) 347 { 348 SFB_ALLOC_REG(hwc) = 0; 349 sfb_account_allocs(num, hwc); 350 } 351 352 static void deallocate_buffers(struct cpu_hw_sf *cpuhw) 353 { 354 if (cpuhw->sfb.sdbt) 355 free_sampling_buffer(&cpuhw->sfb); 356 } 357 358 static int allocate_buffers(struct cpu_hw_sf *cpuhw, struct hw_perf_event *hwc) 359 { 360 unsigned long n_sdb, freq, factor; 361 size_t sample_size; 362 363 /* Calculate sampling buffers using 4K pages 364 * 365 * 1. Determine the sample data size which depends on the used 366 * sampling functions, for example, basic-sampling or 367 * basic-sampling with diagnostic-sampling. 368 * 369 * 2. Use the sampling frequency as input. The sampling buffer is 370 * designed for almost one second. This can be adjusted through 371 * the "factor" variable. 372 * In any case, alloc_sampling_buffer() sets the Alert Request 373 * Control indicator to trigger a measurement-alert to harvest 374 * sample-data-blocks (sdb). 375 * 376 * 3. Compute the number of sample-data-blocks and ensure a minimum 377 * of CPUM_SF_MIN_SDB. Also ensure the upper limit does not 378 * exceed a "calculated" maximum. The symbolic maximum is 379 * designed for basic-sampling only and needs to be increased if 380 * diagnostic-sampling is active. 381 * See also the remarks for these symbolic constants. 382 * 383 * 4. Compute the number of sample-data-block-tables (SDBT) and 384 * ensure a minimum of CPUM_SF_MIN_SDBT (one table can manage up 385 * to 511 SDBs). 386 */ 387 sample_size = sizeof(struct hws_basic_entry); 388 freq = sample_rate_to_freq(&cpuhw->qsi, SAMPL_RATE(hwc)); 389 factor = 1; 390 n_sdb = DIV_ROUND_UP(freq, factor * ((PAGE_SIZE-64) / sample_size)); 391 if (n_sdb < CPUM_SF_MIN_SDB) 392 n_sdb = CPUM_SF_MIN_SDB; 393 394 /* If there is already a sampling buffer allocated, it is very likely 395 * that the sampling facility is enabled too. If the event to be 396 * initialized requires a greater sampling buffer, the allocation must 397 * be postponed. Changing the sampling buffer requires the sampling 398 * facility to be in the disabled state. So, account the number of 399 * required SDBs and let cpumsf_pmu_enable() resize the buffer just 400 * before the event is started. 401 */ 402 sfb_init_allocs(n_sdb, hwc); 403 if (sf_buffer_available(cpuhw)) 404 return 0; 405 406 debug_sprintf_event(sfdbg, 3, 407 "allocate_buffers: rate=%lu f=%lu sdb=%lu/%lu" 408 " sample_size=%lu cpuhw=%p\n", 409 SAMPL_RATE(hwc), freq, n_sdb, sfb_max_limit(hwc), 410 sample_size, cpuhw); 411 412 return alloc_sampling_buffer(&cpuhw->sfb, 413 sfb_pending_allocs(&cpuhw->sfb, hwc)); 414 } 415 416 static unsigned long min_percent(unsigned int percent, unsigned long base, 417 unsigned long min) 418 { 419 return min_t(unsigned long, min, DIV_ROUND_UP(percent * base, 100)); 420 } 421 422 static unsigned long compute_sfb_extent(unsigned long ratio, unsigned long base) 423 { 424 /* Use a percentage-based approach to extend the sampling facility 425 * buffer. Accept up to 5% sample data loss. 426 * Vary the extents between 1% to 5% of the current number of 427 * sample-data-blocks. 428 */ 429 if (ratio <= 5) 430 return 0; 431 if (ratio <= 25) 432 return min_percent(1, base, 1); 433 if (ratio <= 50) 434 return min_percent(1, base, 1); 435 if (ratio <= 75) 436 return min_percent(2, base, 2); 437 if (ratio <= 100) 438 return min_percent(3, base, 3); 439 if (ratio <= 250) 440 return min_percent(4, base, 4); 441 442 return min_percent(5, base, 8); 443 } 444 445 static void sfb_account_overflows(struct cpu_hw_sf *cpuhw, 446 struct hw_perf_event *hwc) 447 { 448 unsigned long ratio, num; 449 450 if (!OVERFLOW_REG(hwc)) 451 return; 452 453 /* The sample_overflow contains the average number of sample data 454 * that has been lost because sample-data-blocks were full. 455 * 456 * Calculate the total number of sample data entries that has been 457 * discarded. Then calculate the ratio of lost samples to total samples 458 * per second in percent. 459 */ 460 ratio = DIV_ROUND_UP(100 * OVERFLOW_REG(hwc) * cpuhw->sfb.num_sdb, 461 sample_rate_to_freq(&cpuhw->qsi, SAMPL_RATE(hwc))); 462 463 /* Compute number of sample-data-blocks */ 464 num = compute_sfb_extent(ratio, cpuhw->sfb.num_sdb); 465 if (num) 466 sfb_account_allocs(num, hwc); 467 468 debug_sprintf_event(sfdbg, 5, "sfb: overflow: overflow=%llu ratio=%lu" 469 " num=%lu\n", OVERFLOW_REG(hwc), ratio, num); 470 OVERFLOW_REG(hwc) = 0; 471 } 472 473 /* extend_sampling_buffer() - Extend sampling buffer 474 * @sfb: Sampling buffer structure (for local CPU) 475 * @hwc: Perf event hardware structure 476 * 477 * Use this function to extend the sampling buffer based on the overflow counter 478 * and postponed allocation extents stored in the specified Perf event hardware. 479 * 480 * Important: This function disables the sampling facility in order to safely 481 * change the sampling buffer structure. Do not call this function 482 * when the PMU is active. 483 */ 484 static void extend_sampling_buffer(struct sf_buffer *sfb, 485 struct hw_perf_event *hwc) 486 { 487 unsigned long num, num_old; 488 int rc; 489 490 num = sfb_pending_allocs(sfb, hwc); 491 if (!num) 492 return; 493 num_old = sfb->num_sdb; 494 495 /* Disable the sampling facility to reset any states and also 496 * clear pending measurement alerts. 497 */ 498 sf_disable(); 499 500 /* Extend the sampling buffer. 501 * This memory allocation typically happens in an atomic context when 502 * called by perf. Because this is a reallocation, it is fine if the 503 * new SDB-request cannot be satisfied immediately. 504 */ 505 rc = realloc_sampling_buffer(sfb, num, GFP_ATOMIC); 506 if (rc) 507 debug_sprintf_event(sfdbg, 5, "sfb: extend: realloc " 508 "failed with rc=%i\n", rc); 509 510 if (sfb_has_pending_allocs(sfb, hwc)) 511 debug_sprintf_event(sfdbg, 5, "sfb: extend: " 512 "req=%lu alloc=%lu remaining=%lu\n", 513 num, sfb->num_sdb - num_old, 514 sfb_pending_allocs(sfb, hwc)); 515 } 516 517 518 /* Number of perf events counting hardware events */ 519 static atomic_t num_events; 520 /* Used to avoid races in calling reserve/release_cpumf_hardware */ 521 static DEFINE_MUTEX(pmc_reserve_mutex); 522 523 #define PMC_INIT 0 524 #define PMC_RELEASE 1 525 #define PMC_FAILURE 2 526 static void setup_pmc_cpu(void *flags) 527 { 528 int err; 529 struct cpu_hw_sf *cpusf = this_cpu_ptr(&cpu_hw_sf); 530 531 err = 0; 532 switch (*((int *) flags)) { 533 case PMC_INIT: 534 memset(cpusf, 0, sizeof(*cpusf)); 535 err = qsi(&cpusf->qsi); 536 if (err) 537 break; 538 cpusf->flags |= PMU_F_RESERVED; 539 err = sf_disable(); 540 if (err) 541 pr_err("Switching off the sampling facility failed " 542 "with rc=%i\n", err); 543 debug_sprintf_event(sfdbg, 5, 544 "setup_pmc_cpu: initialized: cpuhw=%p\n", cpusf); 545 break; 546 case PMC_RELEASE: 547 cpusf->flags &= ~PMU_F_RESERVED; 548 err = sf_disable(); 549 if (err) { 550 pr_err("Switching off the sampling facility failed " 551 "with rc=%i\n", err); 552 } else 553 deallocate_buffers(cpusf); 554 debug_sprintf_event(sfdbg, 5, 555 "setup_pmc_cpu: released: cpuhw=%p\n", cpusf); 556 break; 557 } 558 if (err) 559 *((int *) flags) |= PMC_FAILURE; 560 } 561 562 static void release_pmc_hardware(void) 563 { 564 int flags = PMC_RELEASE; 565 566 irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT); 567 on_each_cpu(setup_pmc_cpu, &flags, 1); 568 } 569 570 static int reserve_pmc_hardware(void) 571 { 572 int flags = PMC_INIT; 573 574 on_each_cpu(setup_pmc_cpu, &flags, 1); 575 if (flags & PMC_FAILURE) { 576 release_pmc_hardware(); 577 return -ENODEV; 578 } 579 irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT); 580 581 return 0; 582 } 583 584 static void hw_perf_event_destroy(struct perf_event *event) 585 { 586 /* Release PMC if this is the last perf event */ 587 if (!atomic_add_unless(&num_events, -1, 1)) { 588 mutex_lock(&pmc_reserve_mutex); 589 if (atomic_dec_return(&num_events) == 0) 590 release_pmc_hardware(); 591 mutex_unlock(&pmc_reserve_mutex); 592 } 593 } 594 595 static void hw_init_period(struct hw_perf_event *hwc, u64 period) 596 { 597 hwc->sample_period = period; 598 hwc->last_period = hwc->sample_period; 599 local64_set(&hwc->period_left, hwc->sample_period); 600 } 601 602 static void hw_reset_registers(struct hw_perf_event *hwc, 603 unsigned long *sdbt_origin) 604 { 605 /* (Re)set to first sample-data-block-table */ 606 TEAR_REG(hwc) = (unsigned long) sdbt_origin; 607 } 608 609 static unsigned long hw_limit_rate(const struct hws_qsi_info_block *si, 610 unsigned long rate) 611 { 612 return clamp_t(unsigned long, rate, 613 si->min_sampl_rate, si->max_sampl_rate); 614 } 615 616 static u32 cpumsf_pid_type(struct perf_event *event, 617 u32 pid, enum pid_type type) 618 { 619 struct task_struct *tsk; 620 621 /* Idle process */ 622 if (!pid) 623 goto out; 624 625 tsk = find_task_by_pid_ns(pid, &init_pid_ns); 626 pid = -1; 627 if (tsk) { 628 /* 629 * Only top level events contain the pid namespace in which 630 * they are created. 631 */ 632 if (event->parent) 633 event = event->parent; 634 pid = __task_pid_nr_ns(tsk, type, event->ns); 635 /* 636 * See also 1d953111b648 637 * "perf/core: Don't report zero PIDs for exiting tasks". 638 */ 639 if (!pid && !pid_alive(tsk)) 640 pid = -1; 641 } 642 out: 643 return pid; 644 } 645 646 static void cpumsf_output_event_pid(struct perf_event *event, 647 struct perf_sample_data *data, 648 struct pt_regs *regs) 649 { 650 u32 pid; 651 struct perf_event_header header; 652 struct perf_output_handle handle; 653 654 /* 655 * Obtain the PID from the basic-sampling data entry and 656 * correct the data->tid_entry.pid value. 657 */ 658 pid = data->tid_entry.pid; 659 660 /* Protect callchain buffers, tasks */ 661 rcu_read_lock(); 662 663 perf_prepare_sample(&header, data, event, regs); 664 if (perf_output_begin(&handle, event, header.size)) 665 goto out; 666 667 /* Update the process ID (see also kernel/events/core.c) */ 668 data->tid_entry.pid = cpumsf_pid_type(event, pid, PIDTYPE_TGID); 669 data->tid_entry.tid = cpumsf_pid_type(event, pid, PIDTYPE_PID); 670 671 perf_output_sample(&handle, &header, data, event); 672 perf_output_end(&handle); 673 out: 674 rcu_read_unlock(); 675 } 676 677 static int __hw_perf_event_init(struct perf_event *event) 678 { 679 struct cpu_hw_sf *cpuhw; 680 struct hws_qsi_info_block si; 681 struct perf_event_attr *attr = &event->attr; 682 struct hw_perf_event *hwc = &event->hw; 683 unsigned long rate; 684 int cpu, err; 685 686 /* Reserve CPU-measurement sampling facility */ 687 err = 0; 688 if (!atomic_inc_not_zero(&num_events)) { 689 mutex_lock(&pmc_reserve_mutex); 690 if (atomic_read(&num_events) == 0 && reserve_pmc_hardware()) 691 err = -EBUSY; 692 else 693 atomic_inc(&num_events); 694 mutex_unlock(&pmc_reserve_mutex); 695 } 696 event->destroy = hw_perf_event_destroy; 697 698 if (err) 699 goto out; 700 701 /* Access per-CPU sampling information (query sampling info) */ 702 /* 703 * The event->cpu value can be -1 to count on every CPU, for example, 704 * when attaching to a task. If this is specified, use the query 705 * sampling info from the current CPU, otherwise use event->cpu to 706 * retrieve the per-CPU information. 707 * Later, cpuhw indicates whether to allocate sampling buffers for a 708 * particular CPU (cpuhw!=NULL) or each online CPU (cpuw==NULL). 709 */ 710 memset(&si, 0, sizeof(si)); 711 cpuhw = NULL; 712 if (event->cpu == -1) 713 qsi(&si); 714 else { 715 /* Event is pinned to a particular CPU, retrieve the per-CPU 716 * sampling structure for accessing the CPU-specific QSI. 717 */ 718 cpuhw = &per_cpu(cpu_hw_sf, event->cpu); 719 si = cpuhw->qsi; 720 } 721 722 /* Check sampling facility authorization and, if not authorized, 723 * fall back to other PMUs. It is safe to check any CPU because 724 * the authorization is identical for all configured CPUs. 725 */ 726 if (!si.as) { 727 err = -ENOENT; 728 goto out; 729 } 730 731 /* Always enable basic sampling */ 732 SAMPL_FLAGS(hwc) = PERF_CPUM_SF_BASIC_MODE; 733 734 /* Check if diagnostic sampling is requested. Deny if the required 735 * sampling authorization is missing. 736 */ 737 if (attr->config == PERF_EVENT_CPUM_SF_DIAG) { 738 if (!si.ad) { 739 err = -EPERM; 740 goto out; 741 } 742 SAMPL_FLAGS(hwc) |= PERF_CPUM_SF_DIAG_MODE; 743 } 744 745 /* Check and set other sampling flags */ 746 if (attr->config1 & PERF_CPUM_SF_FULL_BLOCKS) 747 SAMPL_FLAGS(hwc) |= PERF_CPUM_SF_FULL_BLOCKS; 748 749 /* The sampling information (si) contains information about the 750 * min/max sampling intervals and the CPU speed. So calculate the 751 * correct sampling interval and avoid the whole period adjust 752 * feedback loop. 753 */ 754 rate = 0; 755 if (attr->freq) { 756 if (!attr->sample_freq) { 757 err = -EINVAL; 758 goto out; 759 } 760 rate = freq_to_sample_rate(&si, attr->sample_freq); 761 rate = hw_limit_rate(&si, rate); 762 attr->freq = 0; 763 attr->sample_period = rate; 764 } else { 765 /* The min/max sampling rates specifies the valid range 766 * of sample periods. If the specified sample period is 767 * out of range, limit the period to the range boundary. 768 */ 769 rate = hw_limit_rate(&si, hwc->sample_period); 770 771 /* The perf core maintains a maximum sample rate that is 772 * configurable through the sysctl interface. Ensure the 773 * sampling rate does not exceed this value. This also helps 774 * to avoid throttling when pushing samples with 775 * perf_event_overflow(). 776 */ 777 if (sample_rate_to_freq(&si, rate) > 778 sysctl_perf_event_sample_rate) { 779 err = -EINVAL; 780 debug_sprintf_event(sfdbg, 1, "Sampling rate exceeds maximum perf sample rate\n"); 781 goto out; 782 } 783 } 784 SAMPL_RATE(hwc) = rate; 785 hw_init_period(hwc, SAMPL_RATE(hwc)); 786 787 /* Initialize sample data overflow accounting */ 788 hwc->extra_reg.reg = REG_OVERFLOW; 789 OVERFLOW_REG(hwc) = 0; 790 791 /* Use AUX buffer. No need to allocate it by ourself */ 792 if (attr->config == PERF_EVENT_CPUM_SF_DIAG) 793 return 0; 794 795 /* Allocate the per-CPU sampling buffer using the CPU information 796 * from the event. If the event is not pinned to a particular 797 * CPU (event->cpu == -1; or cpuhw == NULL), allocate sampling 798 * buffers for each online CPU. 799 */ 800 if (cpuhw) 801 /* Event is pinned to a particular CPU */ 802 err = allocate_buffers(cpuhw, hwc); 803 else { 804 /* Event is not pinned, allocate sampling buffer on 805 * each online CPU 806 */ 807 for_each_online_cpu(cpu) { 808 cpuhw = &per_cpu(cpu_hw_sf, cpu); 809 err = allocate_buffers(cpuhw, hwc); 810 if (err) 811 break; 812 } 813 } 814 815 /* If PID/TID sampling is active, replace the default overflow 816 * handler to extract and resolve the PIDs from the basic-sampling 817 * data entries. 818 */ 819 if (event->attr.sample_type & PERF_SAMPLE_TID) 820 if (is_default_overflow_handler(event)) 821 event->overflow_handler = cpumsf_output_event_pid; 822 out: 823 return err; 824 } 825 826 static int cpumsf_pmu_event_init(struct perf_event *event) 827 { 828 int err; 829 830 /* No support for taken branch sampling */ 831 if (has_branch_stack(event)) 832 return -EOPNOTSUPP; 833 834 switch (event->attr.type) { 835 case PERF_TYPE_RAW: 836 if ((event->attr.config != PERF_EVENT_CPUM_SF) && 837 (event->attr.config != PERF_EVENT_CPUM_SF_DIAG)) 838 return -ENOENT; 839 break; 840 case PERF_TYPE_HARDWARE: 841 /* Support sampling of CPU cycles in addition to the 842 * counter facility. However, the counter facility 843 * is more precise and, hence, restrict this PMU to 844 * sampling events only. 845 */ 846 if (event->attr.config != PERF_COUNT_HW_CPU_CYCLES) 847 return -ENOENT; 848 if (!is_sampling_event(event)) 849 return -ENOENT; 850 break; 851 default: 852 return -ENOENT; 853 } 854 855 /* Check online status of the CPU to which the event is pinned */ 856 if (event->cpu >= 0 && !cpu_online(event->cpu)) 857 return -ENODEV; 858 859 /* Force reset of idle/hv excludes regardless of what the 860 * user requested. 861 */ 862 if (event->attr.exclude_hv) 863 event->attr.exclude_hv = 0; 864 if (event->attr.exclude_idle) 865 event->attr.exclude_idle = 0; 866 867 err = __hw_perf_event_init(event); 868 if (unlikely(err)) 869 if (event->destroy) 870 event->destroy(event); 871 return err; 872 } 873 874 static void cpumsf_pmu_enable(struct pmu *pmu) 875 { 876 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 877 struct hw_perf_event *hwc; 878 int err; 879 880 if (cpuhw->flags & PMU_F_ENABLED) 881 return; 882 883 if (cpuhw->flags & PMU_F_ERR_MASK) 884 return; 885 886 /* Check whether to extent the sampling buffer. 887 * 888 * Two conditions trigger an increase of the sampling buffer for a 889 * perf event: 890 * 1. Postponed buffer allocations from the event initialization. 891 * 2. Sampling overflows that contribute to pending allocations. 892 * 893 * Note that the extend_sampling_buffer() function disables the sampling 894 * facility, but it can be fully re-enabled using sampling controls that 895 * have been saved in cpumsf_pmu_disable(). 896 */ 897 if (cpuhw->event) { 898 hwc = &cpuhw->event->hw; 899 if (!(SAMPL_DIAG_MODE(hwc))) { 900 /* 901 * Account number of overflow-designated 902 * buffer extents 903 */ 904 sfb_account_overflows(cpuhw, hwc); 905 if (sfb_has_pending_allocs(&cpuhw->sfb, hwc)) 906 extend_sampling_buffer(&cpuhw->sfb, hwc); 907 } 908 } 909 910 /* (Re)enable the PMU and sampling facility */ 911 cpuhw->flags |= PMU_F_ENABLED; 912 barrier(); 913 914 err = lsctl(&cpuhw->lsctl); 915 if (err) { 916 cpuhw->flags &= ~PMU_F_ENABLED; 917 pr_err("Loading sampling controls failed: op=%i err=%i\n", 918 1, err); 919 return; 920 } 921 922 /* Load current program parameter */ 923 lpp(&S390_lowcore.lpp); 924 925 debug_sprintf_event(sfdbg, 6, "pmu_enable: es=%i cs=%i ed=%i cd=%i " 926 "tear=%p dear=%p\n", cpuhw->lsctl.es, cpuhw->lsctl.cs, 927 cpuhw->lsctl.ed, cpuhw->lsctl.cd, 928 (void *) cpuhw->lsctl.tear, (void *) cpuhw->lsctl.dear); 929 } 930 931 static void cpumsf_pmu_disable(struct pmu *pmu) 932 { 933 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 934 struct hws_lsctl_request_block inactive; 935 struct hws_qsi_info_block si; 936 int err; 937 938 if (!(cpuhw->flags & PMU_F_ENABLED)) 939 return; 940 941 if (cpuhw->flags & PMU_F_ERR_MASK) 942 return; 943 944 /* Switch off sampling activation control */ 945 inactive = cpuhw->lsctl; 946 inactive.cs = 0; 947 inactive.cd = 0; 948 949 err = lsctl(&inactive); 950 if (err) { 951 pr_err("Loading sampling controls failed: op=%i err=%i\n", 952 2, err); 953 return; 954 } 955 956 /* Save state of TEAR and DEAR register contents */ 957 if (!qsi(&si)) { 958 /* TEAR/DEAR values are valid only if the sampling facility is 959 * enabled. Note that cpumsf_pmu_disable() might be called even 960 * for a disabled sampling facility because cpumsf_pmu_enable() 961 * controls the enable/disable state. 962 */ 963 if (si.es) { 964 cpuhw->lsctl.tear = si.tear; 965 cpuhw->lsctl.dear = si.dear; 966 } 967 } else 968 debug_sprintf_event(sfdbg, 3, "cpumsf_pmu_disable: " 969 "qsi() failed with err=%i\n", err); 970 971 cpuhw->flags &= ~PMU_F_ENABLED; 972 } 973 974 /* perf_exclude_event() - Filter event 975 * @event: The perf event 976 * @regs: pt_regs structure 977 * @sde_regs: Sample-data-entry (sde) regs structure 978 * 979 * Filter perf events according to their exclude specification. 980 * 981 * Return non-zero if the event shall be excluded. 982 */ 983 static int perf_exclude_event(struct perf_event *event, struct pt_regs *regs, 984 struct perf_sf_sde_regs *sde_regs) 985 { 986 if (event->attr.exclude_user && user_mode(regs)) 987 return 1; 988 if (event->attr.exclude_kernel && !user_mode(regs)) 989 return 1; 990 if (event->attr.exclude_guest && sde_regs->in_guest) 991 return 1; 992 if (event->attr.exclude_host && !sde_regs->in_guest) 993 return 1; 994 return 0; 995 } 996 997 /* perf_push_sample() - Push samples to perf 998 * @event: The perf event 999 * @sample: Hardware sample data 1000 * 1001 * Use the hardware sample data to create perf event sample. The sample 1002 * is the pushed to the event subsystem and the function checks for 1003 * possible event overflows. If an event overflow occurs, the PMU is 1004 * stopped. 1005 * 1006 * Return non-zero if an event overflow occurred. 1007 */ 1008 static int perf_push_sample(struct perf_event *event, 1009 struct hws_basic_entry *basic) 1010 { 1011 int overflow; 1012 struct pt_regs regs; 1013 struct perf_sf_sde_regs *sde_regs; 1014 struct perf_sample_data data; 1015 1016 /* Setup perf sample */ 1017 perf_sample_data_init(&data, 0, event->hw.last_period); 1018 1019 /* Setup pt_regs to look like an CPU-measurement external interrupt 1020 * using the Program Request Alert code. The regs.int_parm_long 1021 * field which is unused contains additional sample-data-entry related 1022 * indicators. 1023 */ 1024 memset(®s, 0, sizeof(regs)); 1025 regs.int_code = 0x1407; 1026 regs.int_parm = CPU_MF_INT_SF_PRA; 1027 sde_regs = (struct perf_sf_sde_regs *) ®s.int_parm_long; 1028 1029 psw_bits(regs.psw).ia = basic->ia; 1030 psw_bits(regs.psw).dat = basic->T; 1031 psw_bits(regs.psw).wait = basic->W; 1032 psw_bits(regs.psw).pstate = basic->P; 1033 psw_bits(regs.psw).as = basic->AS; 1034 1035 /* 1036 * Use the hardware provided configuration level to decide if the 1037 * sample belongs to a guest or host. If that is not available, 1038 * fall back to the following heuristics: 1039 * A non-zero guest program parameter always indicates a guest 1040 * sample. Some early samples or samples from guests without 1041 * lpp usage would be misaccounted to the host. We use the asn 1042 * value as an addon heuristic to detect most of these guest samples. 1043 * If the value differs from 0xffff (the host value), we assume to 1044 * be a KVM guest. 1045 */ 1046 switch (basic->CL) { 1047 case 1: /* logical partition */ 1048 sde_regs->in_guest = 0; 1049 break; 1050 case 2: /* virtual machine */ 1051 sde_regs->in_guest = 1; 1052 break; 1053 default: /* old machine, use heuristics */ 1054 if (basic->gpp || basic->prim_asn != 0xffff) 1055 sde_regs->in_guest = 1; 1056 break; 1057 } 1058 1059 /* 1060 * Store the PID value from the sample-data-entry to be 1061 * processed and resolved by cpumsf_output_event_pid(). 1062 */ 1063 data.tid_entry.pid = basic->hpp & LPP_PID_MASK; 1064 1065 overflow = 0; 1066 if (perf_exclude_event(event, ®s, sde_regs)) 1067 goto out; 1068 if (perf_event_overflow(event, &data, ®s)) { 1069 overflow = 1; 1070 event->pmu->stop(event, 0); 1071 } 1072 perf_event_update_userpage(event); 1073 out: 1074 return overflow; 1075 } 1076 1077 static void perf_event_count_update(struct perf_event *event, u64 count) 1078 { 1079 local64_add(count, &event->count); 1080 } 1081 1082 static void debug_sample_entry(struct hws_basic_entry *sample, 1083 struct hws_trailer_entry *te) 1084 { 1085 debug_sprintf_event(sfdbg, 4, "hw_collect_samples: Found unknown " 1086 "sampling data entry: te->f=%i basic.def=%04x (%p)\n", 1087 te->f, sample->def, sample); 1088 } 1089 1090 /* hw_collect_samples() - Walk through a sample-data-block and collect samples 1091 * @event: The perf event 1092 * @sdbt: Sample-data-block table 1093 * @overflow: Event overflow counter 1094 * 1095 * Walks through a sample-data-block and collects sampling data entries that are 1096 * then pushed to the perf event subsystem. Depending on the sampling function, 1097 * there can be either basic-sampling or combined-sampling data entries. A 1098 * combined-sampling data entry consists of a basic- and a diagnostic-sampling 1099 * data entry. The sampling function is determined by the flags in the perf 1100 * event hardware structure. The function always works with a combined-sampling 1101 * data entry but ignores the the diagnostic portion if it is not available. 1102 * 1103 * Note that the implementation focuses on basic-sampling data entries and, if 1104 * such an entry is not valid, the entire combined-sampling data entry is 1105 * ignored. 1106 * 1107 * The overflow variables counts the number of samples that has been discarded 1108 * due to a perf event overflow. 1109 */ 1110 static void hw_collect_samples(struct perf_event *event, unsigned long *sdbt, 1111 unsigned long long *overflow) 1112 { 1113 struct hws_trailer_entry *te; 1114 struct hws_basic_entry *sample; 1115 1116 te = (struct hws_trailer_entry *) trailer_entry_ptr(*sdbt); 1117 sample = (struct hws_basic_entry *) *sdbt; 1118 while ((unsigned long *) sample < (unsigned long *) te) { 1119 /* Check for an empty sample */ 1120 if (!sample->def) 1121 break; 1122 1123 /* Update perf event period */ 1124 perf_event_count_update(event, SAMPL_RATE(&event->hw)); 1125 1126 /* Check whether sample is valid */ 1127 if (sample->def == 0x0001) { 1128 /* If an event overflow occurred, the PMU is stopped to 1129 * throttle event delivery. Remaining sample data is 1130 * discarded. 1131 */ 1132 if (!*overflow) { 1133 /* Check whether sample is consistent */ 1134 if (sample->I == 0 && sample->W == 0) { 1135 /* Deliver sample data to perf */ 1136 *overflow = perf_push_sample(event, 1137 sample); 1138 } 1139 } else 1140 /* Count discarded samples */ 1141 *overflow += 1; 1142 } else { 1143 debug_sample_entry(sample, te); 1144 /* Sample slot is not yet written or other record. 1145 * 1146 * This condition can occur if the buffer was reused 1147 * from a combined basic- and diagnostic-sampling. 1148 * If only basic-sampling is then active, entries are 1149 * written into the larger diagnostic entries. 1150 * This is typically the case for sample-data-blocks 1151 * that are not full. Stop processing if the first 1152 * invalid format was detected. 1153 */ 1154 if (!te->f) 1155 break; 1156 } 1157 1158 /* Reset sample slot and advance to next sample */ 1159 sample->def = 0; 1160 sample++; 1161 } 1162 } 1163 1164 /* hw_perf_event_update() - Process sampling buffer 1165 * @event: The perf event 1166 * @flush_all: Flag to also flush partially filled sample-data-blocks 1167 * 1168 * Processes the sampling buffer and create perf event samples. 1169 * The sampling buffer position are retrieved and saved in the TEAR_REG 1170 * register of the specified perf event. 1171 * 1172 * Only full sample-data-blocks are processed. Specify the flash_all flag 1173 * to also walk through partially filled sample-data-blocks. It is ignored 1174 * if PERF_CPUM_SF_FULL_BLOCKS is set. The PERF_CPUM_SF_FULL_BLOCKS flag 1175 * enforces the processing of full sample-data-blocks only (trailer entries 1176 * with the block-full-indicator bit set). 1177 */ 1178 static void hw_perf_event_update(struct perf_event *event, int flush_all) 1179 { 1180 struct hw_perf_event *hwc = &event->hw; 1181 struct hws_trailer_entry *te; 1182 unsigned long *sdbt; 1183 unsigned long long event_overflow, sampl_overflow, num_sdb, te_flags; 1184 int done; 1185 1186 /* 1187 * AUX buffer is used when in diagnostic sampling mode. 1188 * No perf events/samples are created. 1189 */ 1190 if (SAMPL_DIAG_MODE(&event->hw)) 1191 return; 1192 1193 if (flush_all && SDB_FULL_BLOCKS(hwc)) 1194 flush_all = 0; 1195 1196 sdbt = (unsigned long *) TEAR_REG(hwc); 1197 done = event_overflow = sampl_overflow = num_sdb = 0; 1198 while (!done) { 1199 /* Get the trailer entry of the sample-data-block */ 1200 te = (struct hws_trailer_entry *) trailer_entry_ptr(*sdbt); 1201 1202 /* Leave loop if no more work to do (block full indicator) */ 1203 if (!te->f) { 1204 done = 1; 1205 if (!flush_all) 1206 break; 1207 } 1208 1209 /* Check the sample overflow count */ 1210 if (te->overflow) 1211 /* Account sample overflows and, if a particular limit 1212 * is reached, extend the sampling buffer. 1213 * For details, see sfb_account_overflows(). 1214 */ 1215 sampl_overflow += te->overflow; 1216 1217 /* Timestamps are valid for full sample-data-blocks only */ 1218 debug_sprintf_event(sfdbg, 6, "hw_perf_event_update: sdbt=%p " 1219 "overflow=%llu timestamp=0x%llx\n", 1220 sdbt, te->overflow, 1221 (te->f) ? trailer_timestamp(te) : 0ULL); 1222 1223 /* Collect all samples from a single sample-data-block and 1224 * flag if an (perf) event overflow happened. If so, the PMU 1225 * is stopped and remaining samples will be discarded. 1226 */ 1227 hw_collect_samples(event, sdbt, &event_overflow); 1228 num_sdb++; 1229 1230 /* Reset trailer (using compare-double-and-swap) */ 1231 do { 1232 te_flags = te->flags & ~SDB_TE_BUFFER_FULL_MASK; 1233 te_flags |= SDB_TE_ALERT_REQ_MASK; 1234 } while (!cmpxchg_double(&te->flags, &te->overflow, 1235 te->flags, te->overflow, 1236 te_flags, 0ULL)); 1237 1238 /* Advance to next sample-data-block */ 1239 sdbt++; 1240 if (is_link_entry(sdbt)) 1241 sdbt = get_next_sdbt(sdbt); 1242 1243 /* Update event hardware registers */ 1244 TEAR_REG(hwc) = (unsigned long) sdbt; 1245 1246 /* Stop processing sample-data if all samples of the current 1247 * sample-data-block were flushed even if it was not full. 1248 */ 1249 if (flush_all && done) 1250 break; 1251 1252 /* If an event overflow happened, discard samples by 1253 * processing any remaining sample-data-blocks. 1254 */ 1255 if (event_overflow) 1256 flush_all = 1; 1257 } 1258 1259 /* Account sample overflows in the event hardware structure */ 1260 if (sampl_overflow) 1261 OVERFLOW_REG(hwc) = DIV_ROUND_UP(OVERFLOW_REG(hwc) + 1262 sampl_overflow, 1 + num_sdb); 1263 if (sampl_overflow || event_overflow) 1264 debug_sprintf_event(sfdbg, 4, "hw_perf_event_update: " 1265 "overflow stats: sample=%llu event=%llu\n", 1266 sampl_overflow, event_overflow); 1267 } 1268 1269 #define AUX_SDB_INDEX(aux, i) ((i) % aux->sfb.num_sdb) 1270 #define AUX_SDB_NUM(aux, start, end) (end >= start ? end - start + 1 : 0) 1271 #define AUX_SDB_NUM_ALERT(aux) AUX_SDB_NUM(aux, aux->head, aux->alert_mark) 1272 #define AUX_SDB_NUM_EMPTY(aux) AUX_SDB_NUM(aux, aux->head, aux->empty_mark) 1273 1274 /* 1275 * Get trailer entry by index of SDB. 1276 */ 1277 static struct hws_trailer_entry *aux_sdb_trailer(struct aux_buffer *aux, 1278 unsigned long index) 1279 { 1280 unsigned long sdb; 1281 1282 index = AUX_SDB_INDEX(aux, index); 1283 sdb = aux->sdb_index[index]; 1284 return (struct hws_trailer_entry *)trailer_entry_ptr(sdb); 1285 } 1286 1287 /* 1288 * Finish sampling on the cpu. Called by cpumsf_pmu_del() with pmu 1289 * disabled. Collect the full SDBs in AUX buffer which have not reached 1290 * the point of alert indicator. And ignore the SDBs which are not 1291 * full. 1292 * 1293 * 1. Scan SDBs to see how much data is there and consume them. 1294 * 2. Remove alert indicator in the buffer. 1295 */ 1296 static void aux_output_end(struct perf_output_handle *handle) 1297 { 1298 unsigned long i, range_scan, idx; 1299 struct aux_buffer *aux; 1300 struct hws_trailer_entry *te; 1301 1302 aux = perf_get_aux(handle); 1303 if (!aux) 1304 return; 1305 1306 range_scan = AUX_SDB_NUM_ALERT(aux); 1307 for (i = 0, idx = aux->head; i < range_scan; i++, idx++) { 1308 te = aux_sdb_trailer(aux, idx); 1309 if (!(te->flags & SDB_TE_BUFFER_FULL_MASK)) 1310 break; 1311 } 1312 /* i is num of SDBs which are full */ 1313 perf_aux_output_end(handle, i << PAGE_SHIFT); 1314 1315 /* Remove alert indicators in the buffer */ 1316 te = aux_sdb_trailer(aux, aux->alert_mark); 1317 te->flags &= ~SDB_TE_ALERT_REQ_MASK; 1318 1319 debug_sprintf_event(sfdbg, 6, "aux_output_end: collect %lx SDBs\n", i); 1320 } 1321 1322 /* 1323 * Start sampling on the CPU. Called by cpumsf_pmu_add() when an event 1324 * is first added to the CPU or rescheduled again to the CPU. It is called 1325 * with pmu disabled. 1326 * 1327 * 1. Reset the trailer of SDBs to get ready for new data. 1328 * 2. Tell the hardware where to put the data by reset the SDBs buffer 1329 * head(tear/dear). 1330 */ 1331 static int aux_output_begin(struct perf_output_handle *handle, 1332 struct aux_buffer *aux, 1333 struct cpu_hw_sf *cpuhw) 1334 { 1335 unsigned long range; 1336 unsigned long i, range_scan, idx; 1337 unsigned long head, base, offset; 1338 struct hws_trailer_entry *te; 1339 1340 if (WARN_ON_ONCE(handle->head & ~PAGE_MASK)) 1341 return -EINVAL; 1342 1343 aux->head = handle->head >> PAGE_SHIFT; 1344 range = (handle->size + 1) >> PAGE_SHIFT; 1345 if (range <= 1) 1346 return -ENOMEM; 1347 1348 /* 1349 * SDBs between aux->head and aux->empty_mark are already ready 1350 * for new data. range_scan is num of SDBs not within them. 1351 */ 1352 if (range > AUX_SDB_NUM_EMPTY(aux)) { 1353 range_scan = range - AUX_SDB_NUM_EMPTY(aux); 1354 idx = aux->empty_mark + 1; 1355 for (i = 0; i < range_scan; i++, idx++) { 1356 te = aux_sdb_trailer(aux, idx); 1357 te->flags = te->flags & ~SDB_TE_BUFFER_FULL_MASK; 1358 te->flags = te->flags & ~SDB_TE_ALERT_REQ_MASK; 1359 te->overflow = 0; 1360 } 1361 /* Save the position of empty SDBs */ 1362 aux->empty_mark = aux->head + range - 1; 1363 } 1364 1365 /* Set alert indicator */ 1366 aux->alert_mark = aux->head + range/2 - 1; 1367 te = aux_sdb_trailer(aux, aux->alert_mark); 1368 te->flags = te->flags | SDB_TE_ALERT_REQ_MASK; 1369 1370 /* Reset hardware buffer head */ 1371 head = AUX_SDB_INDEX(aux, aux->head); 1372 base = aux->sdbt_index[head / CPUM_SF_SDB_PER_TABLE]; 1373 offset = head % CPUM_SF_SDB_PER_TABLE; 1374 cpuhw->lsctl.tear = base + offset * sizeof(unsigned long); 1375 cpuhw->lsctl.dear = aux->sdb_index[head]; 1376 1377 debug_sprintf_event(sfdbg, 6, "aux_output_begin: " 1378 "head->alert_mark->empty_mark (num_alert, range)" 1379 "[%lx -> %lx -> %lx] (%lx, %lx) " 1380 "tear index %lx, tear %lx dear %lx\n", 1381 aux->head, aux->alert_mark, aux->empty_mark, 1382 AUX_SDB_NUM_ALERT(aux), range, 1383 head / CPUM_SF_SDB_PER_TABLE, 1384 cpuhw->lsctl.tear, 1385 cpuhw->lsctl.dear); 1386 1387 return 0; 1388 } 1389 1390 /* 1391 * Set alert indicator on SDB at index @alert_index while sampler is running. 1392 * 1393 * Return true if successfully. 1394 * Return false if full indicator is already set by hardware sampler. 1395 */ 1396 static bool aux_set_alert(struct aux_buffer *aux, unsigned long alert_index, 1397 unsigned long long *overflow) 1398 { 1399 unsigned long long orig_overflow, orig_flags, new_flags; 1400 struct hws_trailer_entry *te; 1401 1402 te = aux_sdb_trailer(aux, alert_index); 1403 do { 1404 orig_flags = te->flags; 1405 orig_overflow = te->overflow; 1406 *overflow = orig_overflow; 1407 if (orig_flags & SDB_TE_BUFFER_FULL_MASK) { 1408 /* 1409 * SDB is already set by hardware. 1410 * Abort and try to set somewhere 1411 * behind. 1412 */ 1413 return false; 1414 } 1415 new_flags = orig_flags | SDB_TE_ALERT_REQ_MASK; 1416 } while (!cmpxchg_double(&te->flags, &te->overflow, 1417 orig_flags, orig_overflow, 1418 new_flags, 0ULL)); 1419 return true; 1420 } 1421 1422 /* 1423 * aux_reset_buffer() - Scan and setup SDBs for new samples 1424 * @aux: The AUX buffer to set 1425 * @range: The range of SDBs to scan started from aux->head 1426 * @overflow: Set to overflow count 1427 * 1428 * Set alert indicator on the SDB at index of aux->alert_mark. If this SDB is 1429 * marked as empty, check if it is already set full by the hardware sampler. 1430 * If yes, that means new data is already there before we can set an alert 1431 * indicator. Caller should try to set alert indicator to some position behind. 1432 * 1433 * Scan the SDBs in AUX buffer from behind aux->empty_mark. They are used 1434 * previously and have already been consumed by user space. Reset these SDBs 1435 * (clear full indicator and alert indicator) for new data. 1436 * If aux->alert_mark fall in this area, just set it. Overflow count is 1437 * recorded while scanning. 1438 * 1439 * SDBs between aux->head and aux->empty_mark are already reset at last time. 1440 * and ready for new samples. So scanning on this area could be skipped. 1441 * 1442 * Return true if alert indicator is set successfully and false if not. 1443 */ 1444 static bool aux_reset_buffer(struct aux_buffer *aux, unsigned long range, 1445 unsigned long long *overflow) 1446 { 1447 unsigned long long orig_overflow, orig_flags, new_flags; 1448 unsigned long i, range_scan, idx; 1449 struct hws_trailer_entry *te; 1450 1451 if (range <= AUX_SDB_NUM_EMPTY(aux)) 1452 /* 1453 * No need to scan. All SDBs in range are marked as empty. 1454 * Just set alert indicator. Should check race with hardware 1455 * sampler. 1456 */ 1457 return aux_set_alert(aux, aux->alert_mark, overflow); 1458 1459 if (aux->alert_mark <= aux->empty_mark) 1460 /* 1461 * Set alert indicator on empty SDB. Should check race 1462 * with hardware sampler. 1463 */ 1464 if (!aux_set_alert(aux, aux->alert_mark, overflow)) 1465 return false; 1466 1467 /* 1468 * Scan the SDBs to clear full and alert indicator used previously. 1469 * Start scanning from one SDB behind empty_mark. If the new alert 1470 * indicator fall into this range, set it. 1471 */ 1472 range_scan = range - AUX_SDB_NUM_EMPTY(aux); 1473 idx = aux->empty_mark + 1; 1474 for (i = 0; i < range_scan; i++, idx++) { 1475 te = aux_sdb_trailer(aux, idx); 1476 do { 1477 orig_flags = te->flags; 1478 orig_overflow = te->overflow; 1479 new_flags = orig_flags & ~SDB_TE_BUFFER_FULL_MASK; 1480 if (idx == aux->alert_mark) 1481 new_flags |= SDB_TE_ALERT_REQ_MASK; 1482 else 1483 new_flags &= ~SDB_TE_ALERT_REQ_MASK; 1484 } while (!cmpxchg_double(&te->flags, &te->overflow, 1485 orig_flags, orig_overflow, 1486 new_flags, 0ULL)); 1487 *overflow += orig_overflow; 1488 } 1489 1490 /* Update empty_mark to new position */ 1491 aux->empty_mark = aux->head + range - 1; 1492 1493 return true; 1494 } 1495 1496 /* 1497 * Measurement alert handler for diagnostic mode sampling. 1498 */ 1499 static void hw_collect_aux(struct cpu_hw_sf *cpuhw) 1500 { 1501 struct aux_buffer *aux; 1502 int done = 0; 1503 unsigned long range = 0, size; 1504 unsigned long long overflow = 0; 1505 struct perf_output_handle *handle = &cpuhw->handle; 1506 unsigned long num_sdb; 1507 1508 aux = perf_get_aux(handle); 1509 if (WARN_ON_ONCE(!aux)) 1510 return; 1511 1512 /* Inform user space new data arrived */ 1513 size = AUX_SDB_NUM_ALERT(aux) << PAGE_SHIFT; 1514 perf_aux_output_end(handle, size); 1515 num_sdb = aux->sfb.num_sdb; 1516 1517 while (!done) { 1518 /* Get an output handle */ 1519 aux = perf_aux_output_begin(handle, cpuhw->event); 1520 if (handle->size == 0) { 1521 pr_err("The AUX buffer with %lu pages for the " 1522 "diagnostic-sampling mode is full\n", 1523 num_sdb); 1524 debug_sprintf_event(sfdbg, 1, "AUX buffer used up\n"); 1525 break; 1526 } 1527 if (WARN_ON_ONCE(!aux)) 1528 return; 1529 1530 /* Update head and alert_mark to new position */ 1531 aux->head = handle->head >> PAGE_SHIFT; 1532 range = (handle->size + 1) >> PAGE_SHIFT; 1533 if (range == 1) 1534 aux->alert_mark = aux->head; 1535 else 1536 aux->alert_mark = aux->head + range/2 - 1; 1537 1538 if (aux_reset_buffer(aux, range, &overflow)) { 1539 if (!overflow) { 1540 done = 1; 1541 break; 1542 } 1543 size = range << PAGE_SHIFT; 1544 perf_aux_output_end(&cpuhw->handle, size); 1545 pr_err("Sample data caused the AUX buffer with %lu " 1546 "pages to overflow\n", num_sdb); 1547 debug_sprintf_event(sfdbg, 1, "head %lx range %lx " 1548 "overflow %llx\n", 1549 aux->head, range, overflow); 1550 } else { 1551 size = AUX_SDB_NUM_ALERT(aux) << PAGE_SHIFT; 1552 perf_aux_output_end(&cpuhw->handle, size); 1553 debug_sprintf_event(sfdbg, 6, "head %lx alert %lx " 1554 "already full, try another\n", 1555 aux->head, aux->alert_mark); 1556 } 1557 } 1558 1559 if (done) 1560 debug_sprintf_event(sfdbg, 6, "aux_reset_buffer: " 1561 "[%lx -> %lx -> %lx] (%lx, %lx)\n", 1562 aux->head, aux->alert_mark, aux->empty_mark, 1563 AUX_SDB_NUM_ALERT(aux), range); 1564 } 1565 1566 /* 1567 * Callback when freeing AUX buffers. 1568 */ 1569 static void aux_buffer_free(void *data) 1570 { 1571 struct aux_buffer *aux = data; 1572 unsigned long i, num_sdbt; 1573 1574 if (!aux) 1575 return; 1576 1577 /* Free SDBT. SDB is freed by the caller */ 1578 num_sdbt = aux->sfb.num_sdbt; 1579 for (i = 0; i < num_sdbt; i++) 1580 free_page(aux->sdbt_index[i]); 1581 1582 kfree(aux->sdbt_index); 1583 kfree(aux->sdb_index); 1584 kfree(aux); 1585 1586 debug_sprintf_event(sfdbg, 4, "aux_buffer_free: free " 1587 "%lu SDBTs\n", num_sdbt); 1588 } 1589 1590 static void aux_sdb_init(unsigned long sdb) 1591 { 1592 struct hws_trailer_entry *te; 1593 1594 te = (struct hws_trailer_entry *)trailer_entry_ptr(sdb); 1595 1596 /* Save clock base */ 1597 te->clock_base = 1; 1598 memcpy(&te->progusage2, &tod_clock_base[1], 8); 1599 } 1600 1601 /* 1602 * aux_buffer_setup() - Setup AUX buffer for diagnostic mode sampling 1603 * @event: Event the buffer is setup for, event->cpu == -1 means current 1604 * @pages: Array of pointers to buffer pages passed from perf core 1605 * @nr_pages: Total pages 1606 * @snapshot: Flag for snapshot mode 1607 * 1608 * This is the callback when setup an event using AUX buffer. Perf tool can 1609 * trigger this by an additional mmap() call on the event. Unlike the buffer 1610 * for basic samples, AUX buffer belongs to the event. It is scheduled with 1611 * the task among online cpus when it is a per-thread event. 1612 * 1613 * Return the private AUX buffer structure if success or NULL if fails. 1614 */ 1615 static void *aux_buffer_setup(struct perf_event *event, void **pages, 1616 int nr_pages, bool snapshot) 1617 { 1618 struct sf_buffer *sfb; 1619 struct aux_buffer *aux; 1620 unsigned long *new, *tail; 1621 int i, n_sdbt; 1622 1623 if (!nr_pages || !pages) 1624 return NULL; 1625 1626 if (nr_pages > CPUM_SF_MAX_SDB * CPUM_SF_SDB_DIAG_FACTOR) { 1627 pr_err("AUX buffer size (%i pages) is larger than the " 1628 "maximum sampling buffer limit\n", 1629 nr_pages); 1630 return NULL; 1631 } else if (nr_pages < CPUM_SF_MIN_SDB * CPUM_SF_SDB_DIAG_FACTOR) { 1632 pr_err("AUX buffer size (%i pages) is less than the " 1633 "minimum sampling buffer limit\n", 1634 nr_pages); 1635 return NULL; 1636 } 1637 1638 /* Allocate aux_buffer struct for the event */ 1639 aux = kmalloc(sizeof(struct aux_buffer), GFP_KERNEL); 1640 if (!aux) 1641 goto no_aux; 1642 sfb = &aux->sfb; 1643 1644 /* Allocate sdbt_index for fast reference */ 1645 n_sdbt = (nr_pages + CPUM_SF_SDB_PER_TABLE - 1) / CPUM_SF_SDB_PER_TABLE; 1646 aux->sdbt_index = kmalloc_array(n_sdbt, sizeof(void *), GFP_KERNEL); 1647 if (!aux->sdbt_index) 1648 goto no_sdbt_index; 1649 1650 /* Allocate sdb_index for fast reference */ 1651 aux->sdb_index = kmalloc_array(nr_pages, sizeof(void *), GFP_KERNEL); 1652 if (!aux->sdb_index) 1653 goto no_sdb_index; 1654 1655 /* Allocate the first SDBT */ 1656 sfb->num_sdbt = 0; 1657 sfb->sdbt = (unsigned long *) get_zeroed_page(GFP_KERNEL); 1658 if (!sfb->sdbt) 1659 goto no_sdbt; 1660 aux->sdbt_index[sfb->num_sdbt++] = (unsigned long)sfb->sdbt; 1661 tail = sfb->tail = sfb->sdbt; 1662 1663 /* 1664 * Link the provided pages of AUX buffer to SDBT. 1665 * Allocate SDBT if needed. 1666 */ 1667 for (i = 0; i < nr_pages; i++, tail++) { 1668 if (require_table_link(tail)) { 1669 new = (unsigned long *) get_zeroed_page(GFP_KERNEL); 1670 if (!new) 1671 goto no_sdbt; 1672 aux->sdbt_index[sfb->num_sdbt++] = (unsigned long)new; 1673 /* Link current page to tail of chain */ 1674 *tail = (unsigned long)(void *) new + 1; 1675 tail = new; 1676 } 1677 /* Tail is the entry in a SDBT */ 1678 *tail = (unsigned long)pages[i]; 1679 aux->sdb_index[i] = (unsigned long)pages[i]; 1680 aux_sdb_init((unsigned long)pages[i]); 1681 } 1682 sfb->num_sdb = nr_pages; 1683 1684 /* Link the last entry in the SDBT to the first SDBT */ 1685 *tail = (unsigned long) sfb->sdbt + 1; 1686 sfb->tail = tail; 1687 1688 /* 1689 * Initial all SDBs are zeroed. Mark it as empty. 1690 * So there is no need to clear the full indicator 1691 * when this event is first added. 1692 */ 1693 aux->empty_mark = sfb->num_sdb - 1; 1694 1695 debug_sprintf_event(sfdbg, 4, "aux_buffer_setup: setup %lu SDBTs" 1696 " and %lu SDBs\n", 1697 sfb->num_sdbt, sfb->num_sdb); 1698 1699 return aux; 1700 1701 no_sdbt: 1702 /* SDBs (AUX buffer pages) are freed by caller */ 1703 for (i = 0; i < sfb->num_sdbt; i++) 1704 free_page(aux->sdbt_index[i]); 1705 kfree(aux->sdb_index); 1706 no_sdb_index: 1707 kfree(aux->sdbt_index); 1708 no_sdbt_index: 1709 kfree(aux); 1710 no_aux: 1711 return NULL; 1712 } 1713 1714 static void cpumsf_pmu_read(struct perf_event *event) 1715 { 1716 /* Nothing to do ... updates are interrupt-driven */ 1717 } 1718 1719 /* Activate sampling control. 1720 * Next call of pmu_enable() starts sampling. 1721 */ 1722 static void cpumsf_pmu_start(struct perf_event *event, int flags) 1723 { 1724 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 1725 1726 if (WARN_ON_ONCE(!(event->hw.state & PERF_HES_STOPPED))) 1727 return; 1728 1729 if (flags & PERF_EF_RELOAD) 1730 WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE)); 1731 1732 perf_pmu_disable(event->pmu); 1733 event->hw.state = 0; 1734 cpuhw->lsctl.cs = 1; 1735 if (SAMPL_DIAG_MODE(&event->hw)) 1736 cpuhw->lsctl.cd = 1; 1737 perf_pmu_enable(event->pmu); 1738 } 1739 1740 /* Deactivate sampling control. 1741 * Next call of pmu_enable() stops sampling. 1742 */ 1743 static void cpumsf_pmu_stop(struct perf_event *event, int flags) 1744 { 1745 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 1746 1747 if (event->hw.state & PERF_HES_STOPPED) 1748 return; 1749 1750 perf_pmu_disable(event->pmu); 1751 cpuhw->lsctl.cs = 0; 1752 cpuhw->lsctl.cd = 0; 1753 event->hw.state |= PERF_HES_STOPPED; 1754 1755 if ((flags & PERF_EF_UPDATE) && !(event->hw.state & PERF_HES_UPTODATE)) { 1756 hw_perf_event_update(event, 1); 1757 event->hw.state |= PERF_HES_UPTODATE; 1758 } 1759 perf_pmu_enable(event->pmu); 1760 } 1761 1762 static int cpumsf_pmu_add(struct perf_event *event, int flags) 1763 { 1764 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 1765 struct aux_buffer *aux; 1766 int err; 1767 1768 if (cpuhw->flags & PMU_F_IN_USE) 1769 return -EAGAIN; 1770 1771 if (!SAMPL_DIAG_MODE(&event->hw) && !cpuhw->sfb.sdbt) 1772 return -EINVAL; 1773 1774 err = 0; 1775 perf_pmu_disable(event->pmu); 1776 1777 event->hw.state = PERF_HES_UPTODATE | PERF_HES_STOPPED; 1778 1779 /* Set up sampling controls. Always program the sampling register 1780 * using the SDB-table start. Reset TEAR_REG event hardware register 1781 * that is used by hw_perf_event_update() to store the sampling buffer 1782 * position after samples have been flushed. 1783 */ 1784 cpuhw->lsctl.s = 0; 1785 cpuhw->lsctl.h = 1; 1786 cpuhw->lsctl.interval = SAMPL_RATE(&event->hw); 1787 if (!SAMPL_DIAG_MODE(&event->hw)) { 1788 cpuhw->lsctl.tear = (unsigned long) cpuhw->sfb.sdbt; 1789 cpuhw->lsctl.dear = *(unsigned long *) cpuhw->sfb.sdbt; 1790 hw_reset_registers(&event->hw, cpuhw->sfb.sdbt); 1791 } 1792 1793 /* Ensure sampling functions are in the disabled state. If disabled, 1794 * switch on sampling enable control. */ 1795 if (WARN_ON_ONCE(cpuhw->lsctl.es == 1 || cpuhw->lsctl.ed == 1)) { 1796 err = -EAGAIN; 1797 goto out; 1798 } 1799 if (SAMPL_DIAG_MODE(&event->hw)) { 1800 aux = perf_aux_output_begin(&cpuhw->handle, event); 1801 if (!aux) { 1802 err = -EINVAL; 1803 goto out; 1804 } 1805 err = aux_output_begin(&cpuhw->handle, aux, cpuhw); 1806 if (err) 1807 goto out; 1808 cpuhw->lsctl.ed = 1; 1809 } 1810 cpuhw->lsctl.es = 1; 1811 1812 /* Set in_use flag and store event */ 1813 cpuhw->event = event; 1814 cpuhw->flags |= PMU_F_IN_USE; 1815 1816 if (flags & PERF_EF_START) 1817 cpumsf_pmu_start(event, PERF_EF_RELOAD); 1818 out: 1819 perf_event_update_userpage(event); 1820 perf_pmu_enable(event->pmu); 1821 return err; 1822 } 1823 1824 static void cpumsf_pmu_del(struct perf_event *event, int flags) 1825 { 1826 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 1827 1828 perf_pmu_disable(event->pmu); 1829 cpumsf_pmu_stop(event, PERF_EF_UPDATE); 1830 1831 cpuhw->lsctl.es = 0; 1832 cpuhw->lsctl.ed = 0; 1833 cpuhw->flags &= ~PMU_F_IN_USE; 1834 cpuhw->event = NULL; 1835 1836 if (SAMPL_DIAG_MODE(&event->hw)) 1837 aux_output_end(&cpuhw->handle); 1838 perf_event_update_userpage(event); 1839 perf_pmu_enable(event->pmu); 1840 } 1841 1842 CPUMF_EVENT_ATTR(SF, SF_CYCLES_BASIC, PERF_EVENT_CPUM_SF); 1843 CPUMF_EVENT_ATTR(SF, SF_CYCLES_BASIC_DIAG, PERF_EVENT_CPUM_SF_DIAG); 1844 1845 /* Attribute list for CPU_SF. 1846 * 1847 * The availablitiy depends on the CPU_MF sampling facility authorization 1848 * for basic + diagnositic samples. This is determined at initialization 1849 * time by the sampling facility device driver. 1850 * If the authorization for basic samples is turned off, it should be 1851 * also turned off for diagnostic sampling. 1852 * 1853 * During initialization of the device driver, check the authorization 1854 * level for diagnostic sampling and installs the attribute 1855 * file for diagnostic sampling if necessary. 1856 * 1857 * For now install a placeholder to reference all possible attributes: 1858 * SF_CYCLES_BASIC and SF_CYCLES_BASIC_DIAG. 1859 * Add another entry for the final NULL pointer. 1860 */ 1861 enum { 1862 SF_CYCLES_BASIC_ATTR_IDX = 0, 1863 SF_CYCLES_BASIC_DIAG_ATTR_IDX, 1864 SF_CYCLES_ATTR_MAX 1865 }; 1866 1867 static struct attribute *cpumsf_pmu_events_attr[SF_CYCLES_ATTR_MAX + 1] = { 1868 [SF_CYCLES_BASIC_ATTR_IDX] = CPUMF_EVENT_PTR(SF, SF_CYCLES_BASIC) 1869 }; 1870 1871 PMU_FORMAT_ATTR(event, "config:0-63"); 1872 1873 static struct attribute *cpumsf_pmu_format_attr[] = { 1874 &format_attr_event.attr, 1875 NULL, 1876 }; 1877 1878 static struct attribute_group cpumsf_pmu_events_group = { 1879 .name = "events", 1880 .attrs = cpumsf_pmu_events_attr, 1881 }; 1882 static struct attribute_group cpumsf_pmu_format_group = { 1883 .name = "format", 1884 .attrs = cpumsf_pmu_format_attr, 1885 }; 1886 static const struct attribute_group *cpumsf_pmu_attr_groups[] = { 1887 &cpumsf_pmu_events_group, 1888 &cpumsf_pmu_format_group, 1889 NULL, 1890 }; 1891 1892 static struct pmu cpumf_sampling = { 1893 .pmu_enable = cpumsf_pmu_enable, 1894 .pmu_disable = cpumsf_pmu_disable, 1895 1896 .event_init = cpumsf_pmu_event_init, 1897 .add = cpumsf_pmu_add, 1898 .del = cpumsf_pmu_del, 1899 1900 .start = cpumsf_pmu_start, 1901 .stop = cpumsf_pmu_stop, 1902 .read = cpumsf_pmu_read, 1903 1904 .attr_groups = cpumsf_pmu_attr_groups, 1905 1906 .setup_aux = aux_buffer_setup, 1907 .free_aux = aux_buffer_free, 1908 }; 1909 1910 static void cpumf_measurement_alert(struct ext_code ext_code, 1911 unsigned int alert, unsigned long unused) 1912 { 1913 struct cpu_hw_sf *cpuhw; 1914 1915 if (!(alert & CPU_MF_INT_SF_MASK)) 1916 return; 1917 inc_irq_stat(IRQEXT_CMS); 1918 cpuhw = this_cpu_ptr(&cpu_hw_sf); 1919 1920 /* Measurement alerts are shared and might happen when the PMU 1921 * is not reserved. Ignore these alerts in this case. */ 1922 if (!(cpuhw->flags & PMU_F_RESERVED)) 1923 return; 1924 1925 /* The processing below must take care of multiple alert events that 1926 * might be indicated concurrently. */ 1927 1928 /* Program alert request */ 1929 if (alert & CPU_MF_INT_SF_PRA) { 1930 if (cpuhw->flags & PMU_F_IN_USE) 1931 if (SAMPL_DIAG_MODE(&cpuhw->event->hw)) 1932 hw_collect_aux(cpuhw); 1933 else 1934 hw_perf_event_update(cpuhw->event, 0); 1935 else 1936 WARN_ON_ONCE(!(cpuhw->flags & PMU_F_IN_USE)); 1937 } 1938 1939 /* Report measurement alerts only for non-PRA codes */ 1940 if (alert != CPU_MF_INT_SF_PRA) 1941 debug_sprintf_event(sfdbg, 6, "measurement alert: 0x%x\n", alert); 1942 1943 /* Sampling authorization change request */ 1944 if (alert & CPU_MF_INT_SF_SACA) 1945 qsi(&cpuhw->qsi); 1946 1947 /* Loss of sample data due to high-priority machine activities */ 1948 if (alert & CPU_MF_INT_SF_LSDA) { 1949 pr_err("Sample data was lost\n"); 1950 cpuhw->flags |= PMU_F_ERR_LSDA; 1951 sf_disable(); 1952 } 1953 1954 /* Invalid sampling buffer entry */ 1955 if (alert & (CPU_MF_INT_SF_IAE|CPU_MF_INT_SF_ISE)) { 1956 pr_err("A sampling buffer entry is incorrect (alert=0x%x)\n", 1957 alert); 1958 cpuhw->flags |= PMU_F_ERR_IBE; 1959 sf_disable(); 1960 } 1961 } 1962 static int cpusf_pmu_setup(unsigned int cpu, int flags) 1963 { 1964 /* Ignore the notification if no events are scheduled on the PMU. 1965 * This might be racy... 1966 */ 1967 if (!atomic_read(&num_events)) 1968 return 0; 1969 1970 local_irq_disable(); 1971 setup_pmc_cpu(&flags); 1972 local_irq_enable(); 1973 return 0; 1974 } 1975 1976 static int s390_pmu_sf_online_cpu(unsigned int cpu) 1977 { 1978 return cpusf_pmu_setup(cpu, PMC_INIT); 1979 } 1980 1981 static int s390_pmu_sf_offline_cpu(unsigned int cpu) 1982 { 1983 return cpusf_pmu_setup(cpu, PMC_RELEASE); 1984 } 1985 1986 static int param_get_sfb_size(char *buffer, const struct kernel_param *kp) 1987 { 1988 if (!cpum_sf_avail()) 1989 return -ENODEV; 1990 return sprintf(buffer, "%lu,%lu", CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB); 1991 } 1992 1993 static int param_set_sfb_size(const char *val, const struct kernel_param *kp) 1994 { 1995 int rc; 1996 unsigned long min, max; 1997 1998 if (!cpum_sf_avail()) 1999 return -ENODEV; 2000 if (!val || !strlen(val)) 2001 return -EINVAL; 2002 2003 /* Valid parameter values: "min,max" or "max" */ 2004 min = CPUM_SF_MIN_SDB; 2005 max = CPUM_SF_MAX_SDB; 2006 if (strchr(val, ',')) 2007 rc = (sscanf(val, "%lu,%lu", &min, &max) == 2) ? 0 : -EINVAL; 2008 else 2009 rc = kstrtoul(val, 10, &max); 2010 2011 if (min < 2 || min >= max || max > get_num_physpages()) 2012 rc = -EINVAL; 2013 if (rc) 2014 return rc; 2015 2016 sfb_set_limits(min, max); 2017 pr_info("The sampling buffer limits have changed to: " 2018 "min=%lu max=%lu (diag=x%lu)\n", 2019 CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB, CPUM_SF_SDB_DIAG_FACTOR); 2020 return 0; 2021 } 2022 2023 #define param_check_sfb_size(name, p) __param_check(name, p, void) 2024 static const struct kernel_param_ops param_ops_sfb_size = { 2025 .set = param_set_sfb_size, 2026 .get = param_get_sfb_size, 2027 }; 2028 2029 #define RS_INIT_FAILURE_QSI 0x0001 2030 #define RS_INIT_FAILURE_BSDES 0x0002 2031 #define RS_INIT_FAILURE_ALRT 0x0003 2032 #define RS_INIT_FAILURE_PERF 0x0004 2033 static void __init pr_cpumsf_err(unsigned int reason) 2034 { 2035 pr_err("Sampling facility support for perf is not available: " 2036 "reason=%04x\n", reason); 2037 } 2038 2039 static int __init init_cpum_sampling_pmu(void) 2040 { 2041 struct hws_qsi_info_block si; 2042 int err; 2043 2044 if (!cpum_sf_avail()) 2045 return -ENODEV; 2046 2047 memset(&si, 0, sizeof(si)); 2048 if (qsi(&si)) { 2049 pr_cpumsf_err(RS_INIT_FAILURE_QSI); 2050 return -ENODEV; 2051 } 2052 2053 if (!si.as && !si.ad) 2054 return -ENODEV; 2055 2056 if (si.bsdes != sizeof(struct hws_basic_entry)) { 2057 pr_cpumsf_err(RS_INIT_FAILURE_BSDES); 2058 return -EINVAL; 2059 } 2060 2061 if (si.ad) { 2062 sfb_set_limits(CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB); 2063 /* Sampling of diagnostic data authorized, 2064 * install event into attribute list of PMU device. 2065 */ 2066 cpumsf_pmu_events_attr[SF_CYCLES_BASIC_DIAG_ATTR_IDX] = 2067 CPUMF_EVENT_PTR(SF, SF_CYCLES_BASIC_DIAG); 2068 } 2069 2070 sfdbg = debug_register(KMSG_COMPONENT, 2, 1, 80); 2071 if (!sfdbg) { 2072 pr_err("Registering for s390dbf failed\n"); 2073 return -ENOMEM; 2074 } 2075 debug_register_view(sfdbg, &debug_sprintf_view); 2076 2077 err = register_external_irq(EXT_IRQ_MEASURE_ALERT, 2078 cpumf_measurement_alert); 2079 if (err) { 2080 pr_cpumsf_err(RS_INIT_FAILURE_ALRT); 2081 debug_unregister(sfdbg); 2082 goto out; 2083 } 2084 2085 err = perf_pmu_register(&cpumf_sampling, "cpum_sf", PERF_TYPE_RAW); 2086 if (err) { 2087 pr_cpumsf_err(RS_INIT_FAILURE_PERF); 2088 unregister_external_irq(EXT_IRQ_MEASURE_ALERT, 2089 cpumf_measurement_alert); 2090 debug_unregister(sfdbg); 2091 goto out; 2092 } 2093 2094 cpuhp_setup_state(CPUHP_AP_PERF_S390_SF_ONLINE, "perf/s390/sf:online", 2095 s390_pmu_sf_online_cpu, s390_pmu_sf_offline_cpu); 2096 out: 2097 return err; 2098 } 2099 arch_initcall(init_cpum_sampling_pmu); 2100 core_param(cpum_sfb_size, CPUM_SF_MAX_SDB, sfb_size, 0640); 2101