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, "%s: freed sdbt %#lx\n", __func__, 160 (unsigned long)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 struct hws_trailer_entry *te; 167 unsigned long sdb; 168 169 /* Allocate and initialize sample-data-block */ 170 sdb = get_zeroed_page(gfp_flags); 171 if (!sdb) 172 return -ENOMEM; 173 te = (struct hws_trailer_entry *)trailer_entry_ptr(sdb); 174 te->header.a = 1; 175 176 /* Link SDB into the sample-data-block-table */ 177 *sdbt = sdb; 178 179 return 0; 180 } 181 182 /* 183 * realloc_sampling_buffer() - extend sampler memory 184 * 185 * Allocates new sample-data-blocks and adds them to the specified sampling 186 * buffer memory. 187 * 188 * Important: This modifies the sampling buffer and must be called when the 189 * sampling facility is disabled. 190 * 191 * Returns zero on success, non-zero otherwise. 192 */ 193 static int realloc_sampling_buffer(struct sf_buffer *sfb, 194 unsigned long num_sdb, gfp_t gfp_flags) 195 { 196 int i, rc; 197 unsigned long *new, *tail, *tail_prev = NULL; 198 199 if (!sfb->sdbt || !sfb->tail) 200 return -EINVAL; 201 202 if (!is_link_entry(sfb->tail)) 203 return -EINVAL; 204 205 /* Append to the existing sampling buffer, overwriting the table-link 206 * register. 207 * The tail variables always points to the "tail" (last and table-link) 208 * entry in an SDB-table. 209 */ 210 tail = sfb->tail; 211 212 /* Do a sanity check whether the table-link entry points to 213 * the sampling buffer origin. 214 */ 215 if (sfb->sdbt != get_next_sdbt(tail)) { 216 debug_sprintf_event(sfdbg, 3, "%s: " 217 "sampling buffer is not linked: origin %#lx" 218 " tail %#lx\n", __func__, 219 (unsigned long)sfb->sdbt, 220 (unsigned long)tail); 221 return -EINVAL; 222 } 223 224 /* Allocate remaining SDBs */ 225 rc = 0; 226 for (i = 0; i < num_sdb; i++) { 227 /* Allocate a new SDB-table if it is full. */ 228 if (require_table_link(tail)) { 229 new = (unsigned long *) get_zeroed_page(gfp_flags); 230 if (!new) { 231 rc = -ENOMEM; 232 break; 233 } 234 sfb->num_sdbt++; 235 /* Link current page to tail of chain */ 236 *tail = (unsigned long)(void *) new + 1; 237 tail_prev = tail; 238 tail = new; 239 } 240 241 /* Allocate a new sample-data-block. 242 * If there is not enough memory, stop the realloc process 243 * and simply use what was allocated. If this is a temporary 244 * issue, a new realloc call (if required) might succeed. 245 */ 246 rc = alloc_sample_data_block(tail, gfp_flags); 247 if (rc) { 248 /* Undo last SDBT. An SDBT with no SDB at its first 249 * entry but with an SDBT entry instead can not be 250 * handled by the interrupt handler code. 251 * Avoid this situation. 252 */ 253 if (tail_prev) { 254 sfb->num_sdbt--; 255 free_page((unsigned long) new); 256 tail = tail_prev; 257 } 258 break; 259 } 260 sfb->num_sdb++; 261 tail++; 262 tail_prev = new = NULL; /* Allocated at least one SBD */ 263 } 264 265 /* Link sampling buffer to its origin */ 266 *tail = (unsigned long) sfb->sdbt + 1; 267 sfb->tail = tail; 268 269 debug_sprintf_event(sfdbg, 4, "%s: new buffer" 270 " settings: sdbt %lu sdb %lu\n", __func__, 271 sfb->num_sdbt, sfb->num_sdb); 272 return rc; 273 } 274 275 /* 276 * allocate_sampling_buffer() - allocate sampler memory 277 * 278 * Allocates and initializes a sampling buffer structure using the 279 * specified number of sample-data-blocks (SDB). For each allocation, 280 * a 4K page is used. The number of sample-data-block-tables (SDBT) 281 * are calculated from SDBs. 282 * Also set the ALERT_REQ mask in each SDBs trailer. 283 * 284 * Returns zero on success, non-zero otherwise. 285 */ 286 static int alloc_sampling_buffer(struct sf_buffer *sfb, unsigned long num_sdb) 287 { 288 int rc; 289 290 if (sfb->sdbt) 291 return -EINVAL; 292 293 /* Allocate the sample-data-block-table origin */ 294 sfb->sdbt = (unsigned long *) get_zeroed_page(GFP_KERNEL); 295 if (!sfb->sdbt) 296 return -ENOMEM; 297 sfb->num_sdb = 0; 298 sfb->num_sdbt = 1; 299 300 /* Link the table origin to point to itself to prepare for 301 * realloc_sampling_buffer() invocation. 302 */ 303 sfb->tail = sfb->sdbt; 304 *sfb->tail = (unsigned long)(void *) sfb->sdbt + 1; 305 306 /* Allocate requested number of sample-data-blocks */ 307 rc = realloc_sampling_buffer(sfb, num_sdb, GFP_KERNEL); 308 if (rc) { 309 free_sampling_buffer(sfb); 310 debug_sprintf_event(sfdbg, 4, "%s: " 311 "realloc_sampling_buffer failed with rc %i\n", 312 __func__, rc); 313 } else 314 debug_sprintf_event(sfdbg, 4, 315 "%s: tear %#lx dear %#lx\n", __func__, 316 (unsigned long)sfb->sdbt, (unsigned long)*sfb->sdbt); 317 return rc; 318 } 319 320 static void sfb_set_limits(unsigned long min, unsigned long max) 321 { 322 struct hws_qsi_info_block si; 323 324 CPUM_SF_MIN_SDB = min; 325 CPUM_SF_MAX_SDB = max; 326 327 memset(&si, 0, sizeof(si)); 328 if (!qsi(&si)) 329 CPUM_SF_SDB_DIAG_FACTOR = DIV_ROUND_UP(si.dsdes, si.bsdes); 330 } 331 332 static unsigned long sfb_max_limit(struct hw_perf_event *hwc) 333 { 334 return SAMPL_DIAG_MODE(hwc) ? CPUM_SF_MAX_SDB * CPUM_SF_SDB_DIAG_FACTOR 335 : CPUM_SF_MAX_SDB; 336 } 337 338 static unsigned long sfb_pending_allocs(struct sf_buffer *sfb, 339 struct hw_perf_event *hwc) 340 { 341 if (!sfb->sdbt) 342 return SFB_ALLOC_REG(hwc); 343 if (SFB_ALLOC_REG(hwc) > sfb->num_sdb) 344 return SFB_ALLOC_REG(hwc) - sfb->num_sdb; 345 return 0; 346 } 347 348 static int sfb_has_pending_allocs(struct sf_buffer *sfb, 349 struct hw_perf_event *hwc) 350 { 351 return sfb_pending_allocs(sfb, hwc) > 0; 352 } 353 354 static void sfb_account_allocs(unsigned long num, struct hw_perf_event *hwc) 355 { 356 /* Limit the number of SDBs to not exceed the maximum */ 357 num = min_t(unsigned long, num, sfb_max_limit(hwc) - SFB_ALLOC_REG(hwc)); 358 if (num) 359 SFB_ALLOC_REG(hwc) += num; 360 } 361 362 static void sfb_init_allocs(unsigned long num, struct hw_perf_event *hwc) 363 { 364 SFB_ALLOC_REG(hwc) = 0; 365 sfb_account_allocs(num, hwc); 366 } 367 368 static void deallocate_buffers(struct cpu_hw_sf *cpuhw) 369 { 370 if (cpuhw->sfb.sdbt) 371 free_sampling_buffer(&cpuhw->sfb); 372 } 373 374 static int allocate_buffers(struct cpu_hw_sf *cpuhw, struct hw_perf_event *hwc) 375 { 376 unsigned long n_sdb, freq; 377 size_t sample_size; 378 379 /* Calculate sampling buffers using 4K pages 380 * 381 * 1. The sampling size is 32 bytes for basic sampling. This size 382 * is the same for all machine types. Diagnostic 383 * sampling uses auxlilary data buffer setup which provides the 384 * memory for SDBs using linux common code auxiliary trace 385 * setup. 386 * 387 * 2. Function alloc_sampling_buffer() sets the Alert Request 388 * Control indicator to trigger a measurement-alert to harvest 389 * sample-data-blocks (SDB). This is done per SDB. This 390 * measurement alert interrupt fires quick enough to handle 391 * one SDB, on very high frequency and work loads there might 392 * be 2 to 3 SBDs available for sample processing. 393 * Currently there is no need for setup alert request on every 394 * n-th page. This is counterproductive as one IRQ triggers 395 * a very high number of samples to be processed at one IRQ. 396 * 397 * 3. Use the sampling frequency as input. 398 * Compute the number of SDBs and ensure a minimum 399 * of CPUM_SF_MIN_SDB. Depending on frequency add some more 400 * SDBs to handle a higher sampling rate. 401 * Use a minimum of CPUM_SF_MIN_SDB and allow for 100 samples 402 * (one SDB) for every 10000 HZ frequency increment. 403 * 404 * 4. Compute the number of sample-data-block-tables (SDBT) and 405 * ensure a minimum of CPUM_SF_MIN_SDBT (one table can manage up 406 * to 511 SDBs). 407 */ 408 sample_size = sizeof(struct hws_basic_entry); 409 freq = sample_rate_to_freq(&cpuhw->qsi, SAMPL_RATE(hwc)); 410 n_sdb = CPUM_SF_MIN_SDB + DIV_ROUND_UP(freq, 10000); 411 412 /* If there is already a sampling buffer allocated, it is very likely 413 * that the sampling facility is enabled too. If the event to be 414 * initialized requires a greater sampling buffer, the allocation must 415 * be postponed. Changing the sampling buffer requires the sampling 416 * facility to be in the disabled state. So, account the number of 417 * required SDBs and let cpumsf_pmu_enable() resize the buffer just 418 * before the event is started. 419 */ 420 sfb_init_allocs(n_sdb, hwc); 421 if (sf_buffer_available(cpuhw)) 422 return 0; 423 424 debug_sprintf_event(sfdbg, 3, 425 "%s: rate %lu f %lu sdb %lu/%lu" 426 " sample_size %lu cpuhw %p\n", __func__, 427 SAMPL_RATE(hwc), freq, n_sdb, sfb_max_limit(hwc), 428 sample_size, cpuhw); 429 430 return alloc_sampling_buffer(&cpuhw->sfb, 431 sfb_pending_allocs(&cpuhw->sfb, hwc)); 432 } 433 434 static unsigned long min_percent(unsigned int percent, unsigned long base, 435 unsigned long min) 436 { 437 return min_t(unsigned long, min, DIV_ROUND_UP(percent * base, 100)); 438 } 439 440 static unsigned long compute_sfb_extent(unsigned long ratio, unsigned long base) 441 { 442 /* Use a percentage-based approach to extend the sampling facility 443 * buffer. Accept up to 5% sample data loss. 444 * Vary the extents between 1% to 5% of the current number of 445 * sample-data-blocks. 446 */ 447 if (ratio <= 5) 448 return 0; 449 if (ratio <= 25) 450 return min_percent(1, base, 1); 451 if (ratio <= 50) 452 return min_percent(1, base, 1); 453 if (ratio <= 75) 454 return min_percent(2, base, 2); 455 if (ratio <= 100) 456 return min_percent(3, base, 3); 457 if (ratio <= 250) 458 return min_percent(4, base, 4); 459 460 return min_percent(5, base, 8); 461 } 462 463 static void sfb_account_overflows(struct cpu_hw_sf *cpuhw, 464 struct hw_perf_event *hwc) 465 { 466 unsigned long ratio, num; 467 468 if (!OVERFLOW_REG(hwc)) 469 return; 470 471 /* The sample_overflow contains the average number of sample data 472 * that has been lost because sample-data-blocks were full. 473 * 474 * Calculate the total number of sample data entries that has been 475 * discarded. Then calculate the ratio of lost samples to total samples 476 * per second in percent. 477 */ 478 ratio = DIV_ROUND_UP(100 * OVERFLOW_REG(hwc) * cpuhw->sfb.num_sdb, 479 sample_rate_to_freq(&cpuhw->qsi, SAMPL_RATE(hwc))); 480 481 /* Compute number of sample-data-blocks */ 482 num = compute_sfb_extent(ratio, cpuhw->sfb.num_sdb); 483 if (num) 484 sfb_account_allocs(num, hwc); 485 486 debug_sprintf_event(sfdbg, 5, "%s: overflow %llu ratio %lu num %lu\n", 487 __func__, OVERFLOW_REG(hwc), ratio, num); 488 OVERFLOW_REG(hwc) = 0; 489 } 490 491 /* extend_sampling_buffer() - Extend sampling buffer 492 * @sfb: Sampling buffer structure (for local CPU) 493 * @hwc: Perf event hardware structure 494 * 495 * Use this function to extend the sampling buffer based on the overflow counter 496 * and postponed allocation extents stored in the specified Perf event hardware. 497 * 498 * Important: This function disables the sampling facility in order to safely 499 * change the sampling buffer structure. Do not call this function 500 * when the PMU is active. 501 */ 502 static void extend_sampling_buffer(struct sf_buffer *sfb, 503 struct hw_perf_event *hwc) 504 { 505 unsigned long num, num_old; 506 int rc; 507 508 num = sfb_pending_allocs(sfb, hwc); 509 if (!num) 510 return; 511 num_old = sfb->num_sdb; 512 513 /* Disable the sampling facility to reset any states and also 514 * clear pending measurement alerts. 515 */ 516 sf_disable(); 517 518 /* Extend the sampling buffer. 519 * This memory allocation typically happens in an atomic context when 520 * called by perf. Because this is a reallocation, it is fine if the 521 * new SDB-request cannot be satisfied immediately. 522 */ 523 rc = realloc_sampling_buffer(sfb, num, GFP_ATOMIC); 524 if (rc) 525 debug_sprintf_event(sfdbg, 5, "%s: realloc failed with rc %i\n", 526 __func__, rc); 527 528 if (sfb_has_pending_allocs(sfb, hwc)) 529 debug_sprintf_event(sfdbg, 5, "%s: " 530 "req %lu alloc %lu remaining %lu\n", 531 __func__, num, sfb->num_sdb - num_old, 532 sfb_pending_allocs(sfb, hwc)); 533 } 534 535 /* Number of perf events counting hardware events */ 536 static atomic_t num_events; 537 /* Used to avoid races in calling reserve/release_cpumf_hardware */ 538 static DEFINE_MUTEX(pmc_reserve_mutex); 539 540 #define PMC_INIT 0 541 #define PMC_RELEASE 1 542 #define PMC_FAILURE 2 543 static void setup_pmc_cpu(void *flags) 544 { 545 int err; 546 struct cpu_hw_sf *cpusf = this_cpu_ptr(&cpu_hw_sf); 547 548 err = 0; 549 switch (*((int *) flags)) { 550 case PMC_INIT: 551 memset(cpusf, 0, sizeof(*cpusf)); 552 err = qsi(&cpusf->qsi); 553 if (err) 554 break; 555 cpusf->flags |= PMU_F_RESERVED; 556 err = sf_disable(); 557 if (err) 558 pr_err("Switching off the sampling facility failed " 559 "with rc %i\n", err); 560 debug_sprintf_event(sfdbg, 5, 561 "%s: initialized: cpuhw %p\n", __func__, 562 cpusf); 563 break; 564 case PMC_RELEASE: 565 cpusf->flags &= ~PMU_F_RESERVED; 566 err = sf_disable(); 567 if (err) { 568 pr_err("Switching off the sampling facility failed " 569 "with rc %i\n", err); 570 } else 571 deallocate_buffers(cpusf); 572 debug_sprintf_event(sfdbg, 5, 573 "%s: released: cpuhw %p\n", __func__, 574 cpusf); 575 break; 576 } 577 if (err) 578 *((int *) flags) |= PMC_FAILURE; 579 } 580 581 static void release_pmc_hardware(void) 582 { 583 int flags = PMC_RELEASE; 584 585 irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT); 586 on_each_cpu(setup_pmc_cpu, &flags, 1); 587 } 588 589 static int reserve_pmc_hardware(void) 590 { 591 int flags = PMC_INIT; 592 593 on_each_cpu(setup_pmc_cpu, &flags, 1); 594 if (flags & PMC_FAILURE) { 595 release_pmc_hardware(); 596 return -ENODEV; 597 } 598 irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT); 599 600 return 0; 601 } 602 603 static void hw_perf_event_destroy(struct perf_event *event) 604 { 605 /* Release PMC if this is the last perf event */ 606 if (!atomic_add_unless(&num_events, -1, 1)) { 607 mutex_lock(&pmc_reserve_mutex); 608 if (atomic_dec_return(&num_events) == 0) 609 release_pmc_hardware(); 610 mutex_unlock(&pmc_reserve_mutex); 611 } 612 } 613 614 static void hw_init_period(struct hw_perf_event *hwc, u64 period) 615 { 616 hwc->sample_period = period; 617 hwc->last_period = hwc->sample_period; 618 local64_set(&hwc->period_left, hwc->sample_period); 619 } 620 621 static unsigned long hw_limit_rate(const struct hws_qsi_info_block *si, 622 unsigned long rate) 623 { 624 return clamp_t(unsigned long, rate, 625 si->min_sampl_rate, si->max_sampl_rate); 626 } 627 628 static u32 cpumsf_pid_type(struct perf_event *event, 629 u32 pid, enum pid_type type) 630 { 631 struct task_struct *tsk; 632 633 /* Idle process */ 634 if (!pid) 635 goto out; 636 637 tsk = find_task_by_pid_ns(pid, &init_pid_ns); 638 pid = -1; 639 if (tsk) { 640 /* 641 * Only top level events contain the pid namespace in which 642 * they are created. 643 */ 644 if (event->parent) 645 event = event->parent; 646 pid = __task_pid_nr_ns(tsk, type, event->ns); 647 /* 648 * See also 1d953111b648 649 * "perf/core: Don't report zero PIDs for exiting tasks". 650 */ 651 if (!pid && !pid_alive(tsk)) 652 pid = -1; 653 } 654 out: 655 return pid; 656 } 657 658 static void cpumsf_output_event_pid(struct perf_event *event, 659 struct perf_sample_data *data, 660 struct pt_regs *regs) 661 { 662 u32 pid; 663 struct perf_event_header header; 664 struct perf_output_handle handle; 665 666 /* 667 * Obtain the PID from the basic-sampling data entry and 668 * correct the data->tid_entry.pid value. 669 */ 670 pid = data->tid_entry.pid; 671 672 /* Protect callchain buffers, tasks */ 673 rcu_read_lock(); 674 675 perf_prepare_sample(&header, data, event, regs); 676 if (perf_output_begin(&handle, data, event, header.size)) 677 goto out; 678 679 /* Update the process ID (see also kernel/events/core.c) */ 680 data->tid_entry.pid = cpumsf_pid_type(event, pid, PIDTYPE_TGID); 681 data->tid_entry.tid = cpumsf_pid_type(event, pid, PIDTYPE_PID); 682 683 perf_output_sample(&handle, &header, data, event); 684 perf_output_end(&handle); 685 out: 686 rcu_read_unlock(); 687 } 688 689 static unsigned long getrate(bool freq, unsigned long sample, 690 struct hws_qsi_info_block *si) 691 { 692 unsigned long rate; 693 694 if (freq) { 695 rate = freq_to_sample_rate(si, sample); 696 rate = hw_limit_rate(si, rate); 697 } else { 698 /* The min/max sampling rates specifies the valid range 699 * of sample periods. If the specified sample period is 700 * out of range, limit the period to the range boundary. 701 */ 702 rate = hw_limit_rate(si, sample); 703 704 /* The perf core maintains a maximum sample rate that is 705 * configurable through the sysctl interface. Ensure the 706 * sampling rate does not exceed this value. This also helps 707 * to avoid throttling when pushing samples with 708 * perf_event_overflow(). 709 */ 710 if (sample_rate_to_freq(si, rate) > 711 sysctl_perf_event_sample_rate) { 712 debug_sprintf_event(sfdbg, 1, "%s: " 713 "Sampling rate exceeds maximum " 714 "perf sample rate\n", __func__); 715 rate = 0; 716 } 717 } 718 return rate; 719 } 720 721 /* The sampling information (si) contains information about the 722 * min/max sampling intervals and the CPU speed. So calculate the 723 * correct sampling interval and avoid the whole period adjust 724 * feedback loop. 725 * 726 * Since the CPU Measurement sampling facility can not handle frequency 727 * calculate the sampling interval when frequency is specified using 728 * this formula: 729 * interval := cpu_speed * 1000000 / sample_freq 730 * 731 * Returns errno on bad input and zero on success with parameter interval 732 * set to the correct sampling rate. 733 * 734 * Note: This function turns off freq bit to avoid calling function 735 * perf_adjust_period(). This causes frequency adjustment in the common 736 * code part which causes tremendous variations in the counter values. 737 */ 738 static int __hw_perf_event_init_rate(struct perf_event *event, 739 struct hws_qsi_info_block *si) 740 { 741 struct perf_event_attr *attr = &event->attr; 742 struct hw_perf_event *hwc = &event->hw; 743 unsigned long rate; 744 745 if (attr->freq) { 746 if (!attr->sample_freq) 747 return -EINVAL; 748 rate = getrate(attr->freq, attr->sample_freq, si); 749 attr->freq = 0; /* Don't call perf_adjust_period() */ 750 SAMPL_FLAGS(hwc) |= PERF_CPUM_SF_FREQ_MODE; 751 } else { 752 rate = getrate(attr->freq, attr->sample_period, si); 753 if (!rate) 754 return -EINVAL; 755 } 756 attr->sample_period = rate; 757 SAMPL_RATE(hwc) = rate; 758 hw_init_period(hwc, SAMPL_RATE(hwc)); 759 debug_sprintf_event(sfdbg, 4, "%s: cpu %d period %#llx freq %d,%#lx\n", 760 __func__, event->cpu, event->attr.sample_period, 761 event->attr.freq, SAMPLE_FREQ_MODE(hwc)); 762 return 0; 763 } 764 765 static int __hw_perf_event_init(struct perf_event *event) 766 { 767 struct cpu_hw_sf *cpuhw; 768 struct hws_qsi_info_block si; 769 struct perf_event_attr *attr = &event->attr; 770 struct hw_perf_event *hwc = &event->hw; 771 int cpu, err; 772 773 /* Reserve CPU-measurement sampling facility */ 774 err = 0; 775 if (!atomic_inc_not_zero(&num_events)) { 776 mutex_lock(&pmc_reserve_mutex); 777 if (atomic_read(&num_events) == 0 && reserve_pmc_hardware()) 778 err = -EBUSY; 779 else 780 atomic_inc(&num_events); 781 mutex_unlock(&pmc_reserve_mutex); 782 } 783 event->destroy = hw_perf_event_destroy; 784 785 if (err) 786 goto out; 787 788 /* Access per-CPU sampling information (query sampling info) */ 789 /* 790 * The event->cpu value can be -1 to count on every CPU, for example, 791 * when attaching to a task. If this is specified, use the query 792 * sampling info from the current CPU, otherwise use event->cpu to 793 * retrieve the per-CPU information. 794 * Later, cpuhw indicates whether to allocate sampling buffers for a 795 * particular CPU (cpuhw!=NULL) or each online CPU (cpuw==NULL). 796 */ 797 memset(&si, 0, sizeof(si)); 798 cpuhw = NULL; 799 if (event->cpu == -1) 800 qsi(&si); 801 else { 802 /* Event is pinned to a particular CPU, retrieve the per-CPU 803 * sampling structure for accessing the CPU-specific QSI. 804 */ 805 cpuhw = &per_cpu(cpu_hw_sf, event->cpu); 806 si = cpuhw->qsi; 807 } 808 809 /* Check sampling facility authorization and, if not authorized, 810 * fall back to other PMUs. It is safe to check any CPU because 811 * the authorization is identical for all configured CPUs. 812 */ 813 if (!si.as) { 814 err = -ENOENT; 815 goto out; 816 } 817 818 if (si.ribm & CPU_MF_SF_RIBM_NOTAV) { 819 pr_warn("CPU Measurement Facility sampling is temporarily not available\n"); 820 err = -EBUSY; 821 goto out; 822 } 823 824 /* Always enable basic sampling */ 825 SAMPL_FLAGS(hwc) = PERF_CPUM_SF_BASIC_MODE; 826 827 /* Check if diagnostic sampling is requested. Deny if the required 828 * sampling authorization is missing. 829 */ 830 if (attr->config == PERF_EVENT_CPUM_SF_DIAG) { 831 if (!si.ad) { 832 err = -EPERM; 833 goto out; 834 } 835 SAMPL_FLAGS(hwc) |= PERF_CPUM_SF_DIAG_MODE; 836 } 837 838 /* Check and set other sampling flags */ 839 if (attr->config1 & PERF_CPUM_SF_FULL_BLOCKS) 840 SAMPL_FLAGS(hwc) |= PERF_CPUM_SF_FULL_BLOCKS; 841 842 err = __hw_perf_event_init_rate(event, &si); 843 if (err) 844 goto out; 845 846 /* Initialize sample data overflow accounting */ 847 hwc->extra_reg.reg = REG_OVERFLOW; 848 OVERFLOW_REG(hwc) = 0; 849 850 /* Use AUX buffer. No need to allocate it by ourself */ 851 if (attr->config == PERF_EVENT_CPUM_SF_DIAG) 852 return 0; 853 854 /* Allocate the per-CPU sampling buffer using the CPU information 855 * from the event. If the event is not pinned to a particular 856 * CPU (event->cpu == -1; or cpuhw == NULL), allocate sampling 857 * buffers for each online CPU. 858 */ 859 if (cpuhw) 860 /* Event is pinned to a particular CPU */ 861 err = allocate_buffers(cpuhw, hwc); 862 else { 863 /* Event is not pinned, allocate sampling buffer on 864 * each online CPU 865 */ 866 for_each_online_cpu(cpu) { 867 cpuhw = &per_cpu(cpu_hw_sf, cpu); 868 err = allocate_buffers(cpuhw, hwc); 869 if (err) 870 break; 871 } 872 } 873 874 /* If PID/TID sampling is active, replace the default overflow 875 * handler to extract and resolve the PIDs from the basic-sampling 876 * data entries. 877 */ 878 if (event->attr.sample_type & PERF_SAMPLE_TID) 879 if (is_default_overflow_handler(event)) 880 event->overflow_handler = cpumsf_output_event_pid; 881 out: 882 return err; 883 } 884 885 static bool is_callchain_event(struct perf_event *event) 886 { 887 u64 sample_type = event->attr.sample_type; 888 889 return sample_type & (PERF_SAMPLE_CALLCHAIN | PERF_SAMPLE_REGS_USER | 890 PERF_SAMPLE_STACK_USER); 891 } 892 893 static int cpumsf_pmu_event_init(struct perf_event *event) 894 { 895 int err; 896 897 /* No support for taken branch sampling */ 898 /* No support for callchain, stacks and registers */ 899 if (has_branch_stack(event) || is_callchain_event(event)) 900 return -EOPNOTSUPP; 901 902 switch (event->attr.type) { 903 case PERF_TYPE_RAW: 904 if ((event->attr.config != PERF_EVENT_CPUM_SF) && 905 (event->attr.config != PERF_EVENT_CPUM_SF_DIAG)) 906 return -ENOENT; 907 break; 908 case PERF_TYPE_HARDWARE: 909 /* Support sampling of CPU cycles in addition to the 910 * counter facility. However, the counter facility 911 * is more precise and, hence, restrict this PMU to 912 * sampling events only. 913 */ 914 if (event->attr.config != PERF_COUNT_HW_CPU_CYCLES) 915 return -ENOENT; 916 if (!is_sampling_event(event)) 917 return -ENOENT; 918 break; 919 default: 920 return -ENOENT; 921 } 922 923 /* Check online status of the CPU to which the event is pinned */ 924 if (event->cpu >= 0 && !cpu_online(event->cpu)) 925 return -ENODEV; 926 927 /* Force reset of idle/hv excludes regardless of what the 928 * user requested. 929 */ 930 if (event->attr.exclude_hv) 931 event->attr.exclude_hv = 0; 932 if (event->attr.exclude_idle) 933 event->attr.exclude_idle = 0; 934 935 err = __hw_perf_event_init(event); 936 if (unlikely(err)) 937 if (event->destroy) 938 event->destroy(event); 939 return err; 940 } 941 942 static void cpumsf_pmu_enable(struct pmu *pmu) 943 { 944 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 945 struct hw_perf_event *hwc; 946 int err; 947 948 if (cpuhw->flags & PMU_F_ENABLED) 949 return; 950 951 if (cpuhw->flags & PMU_F_ERR_MASK) 952 return; 953 954 /* Check whether to extent the sampling buffer. 955 * 956 * Two conditions trigger an increase of the sampling buffer for a 957 * perf event: 958 * 1. Postponed buffer allocations from the event initialization. 959 * 2. Sampling overflows that contribute to pending allocations. 960 * 961 * Note that the extend_sampling_buffer() function disables the sampling 962 * facility, but it can be fully re-enabled using sampling controls that 963 * have been saved in cpumsf_pmu_disable(). 964 */ 965 if (cpuhw->event) { 966 hwc = &cpuhw->event->hw; 967 if (!(SAMPL_DIAG_MODE(hwc))) { 968 /* 969 * Account number of overflow-designated 970 * buffer extents 971 */ 972 sfb_account_overflows(cpuhw, hwc); 973 extend_sampling_buffer(&cpuhw->sfb, hwc); 974 } 975 /* Rate may be adjusted with ioctl() */ 976 cpuhw->lsctl.interval = SAMPL_RATE(&cpuhw->event->hw); 977 } 978 979 /* (Re)enable the PMU and sampling facility */ 980 cpuhw->flags |= PMU_F_ENABLED; 981 barrier(); 982 983 err = lsctl(&cpuhw->lsctl); 984 if (err) { 985 cpuhw->flags &= ~PMU_F_ENABLED; 986 pr_err("Loading sampling controls failed: op %i err %i\n", 987 1, err); 988 return; 989 } 990 991 /* Load current program parameter */ 992 lpp(&S390_lowcore.lpp); 993 994 debug_sprintf_event(sfdbg, 6, "%s: es %i cs %i ed %i cd %i " 995 "interval %#lx tear %#lx dear %#lx\n", __func__, 996 cpuhw->lsctl.es, cpuhw->lsctl.cs, cpuhw->lsctl.ed, 997 cpuhw->lsctl.cd, cpuhw->lsctl.interval, 998 cpuhw->lsctl.tear, cpuhw->lsctl.dear); 999 } 1000 1001 static void cpumsf_pmu_disable(struct pmu *pmu) 1002 { 1003 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 1004 struct hws_lsctl_request_block inactive; 1005 struct hws_qsi_info_block si; 1006 int err; 1007 1008 if (!(cpuhw->flags & PMU_F_ENABLED)) 1009 return; 1010 1011 if (cpuhw->flags & PMU_F_ERR_MASK) 1012 return; 1013 1014 /* Switch off sampling activation control */ 1015 inactive = cpuhw->lsctl; 1016 inactive.cs = 0; 1017 inactive.cd = 0; 1018 1019 err = lsctl(&inactive); 1020 if (err) { 1021 pr_err("Loading sampling controls failed: op %i err %i\n", 1022 2, err); 1023 return; 1024 } 1025 1026 /* Save state of TEAR and DEAR register contents */ 1027 err = qsi(&si); 1028 if (!err) { 1029 /* TEAR/DEAR values are valid only if the sampling facility is 1030 * enabled. Note that cpumsf_pmu_disable() might be called even 1031 * for a disabled sampling facility because cpumsf_pmu_enable() 1032 * controls the enable/disable state. 1033 */ 1034 if (si.es) { 1035 cpuhw->lsctl.tear = si.tear; 1036 cpuhw->lsctl.dear = si.dear; 1037 } 1038 } else 1039 debug_sprintf_event(sfdbg, 3, "%s: qsi() failed with err %i\n", 1040 __func__, err); 1041 1042 cpuhw->flags &= ~PMU_F_ENABLED; 1043 } 1044 1045 /* perf_exclude_event() - Filter event 1046 * @event: The perf event 1047 * @regs: pt_regs structure 1048 * @sde_regs: Sample-data-entry (sde) regs structure 1049 * 1050 * Filter perf events according to their exclude specification. 1051 * 1052 * Return non-zero if the event shall be excluded. 1053 */ 1054 static int perf_exclude_event(struct perf_event *event, struct pt_regs *regs, 1055 struct perf_sf_sde_regs *sde_regs) 1056 { 1057 if (event->attr.exclude_user && user_mode(regs)) 1058 return 1; 1059 if (event->attr.exclude_kernel && !user_mode(regs)) 1060 return 1; 1061 if (event->attr.exclude_guest && sde_regs->in_guest) 1062 return 1; 1063 if (event->attr.exclude_host && !sde_regs->in_guest) 1064 return 1; 1065 return 0; 1066 } 1067 1068 /* perf_push_sample() - Push samples to perf 1069 * @event: The perf event 1070 * @sample: Hardware sample data 1071 * 1072 * Use the hardware sample data to create perf event sample. The sample 1073 * is the pushed to the event subsystem and the function checks for 1074 * possible event overflows. If an event overflow occurs, the PMU is 1075 * stopped. 1076 * 1077 * Return non-zero if an event overflow occurred. 1078 */ 1079 static int perf_push_sample(struct perf_event *event, 1080 struct hws_basic_entry *basic) 1081 { 1082 int overflow; 1083 struct pt_regs regs; 1084 struct perf_sf_sde_regs *sde_regs; 1085 struct perf_sample_data data; 1086 1087 /* Setup perf sample */ 1088 perf_sample_data_init(&data, 0, event->hw.last_period); 1089 1090 /* Setup pt_regs to look like an CPU-measurement external interrupt 1091 * using the Program Request Alert code. The regs.int_parm_long 1092 * field which is unused contains additional sample-data-entry related 1093 * indicators. 1094 */ 1095 memset(®s, 0, sizeof(regs)); 1096 regs.int_code = 0x1407; 1097 regs.int_parm = CPU_MF_INT_SF_PRA; 1098 sde_regs = (struct perf_sf_sde_regs *) ®s.int_parm_long; 1099 1100 psw_bits(regs.psw).ia = basic->ia; 1101 psw_bits(regs.psw).dat = basic->T; 1102 psw_bits(regs.psw).wait = basic->W; 1103 psw_bits(regs.psw).pstate = basic->P; 1104 psw_bits(regs.psw).as = basic->AS; 1105 1106 /* 1107 * Use the hardware provided configuration level to decide if the 1108 * sample belongs to a guest or host. If that is not available, 1109 * fall back to the following heuristics: 1110 * A non-zero guest program parameter always indicates a guest 1111 * sample. Some early samples or samples from guests without 1112 * lpp usage would be misaccounted to the host. We use the asn 1113 * value as an addon heuristic to detect most of these guest samples. 1114 * If the value differs from 0xffff (the host value), we assume to 1115 * be a KVM guest. 1116 */ 1117 switch (basic->CL) { 1118 case 1: /* logical partition */ 1119 sde_regs->in_guest = 0; 1120 break; 1121 case 2: /* virtual machine */ 1122 sde_regs->in_guest = 1; 1123 break; 1124 default: /* old machine, use heuristics */ 1125 if (basic->gpp || basic->prim_asn != 0xffff) 1126 sde_regs->in_guest = 1; 1127 break; 1128 } 1129 1130 /* 1131 * Store the PID value from the sample-data-entry to be 1132 * processed and resolved by cpumsf_output_event_pid(). 1133 */ 1134 data.tid_entry.pid = basic->hpp & LPP_PID_MASK; 1135 1136 overflow = 0; 1137 if (perf_exclude_event(event, ®s, sde_regs)) 1138 goto out; 1139 if (perf_event_overflow(event, &data, ®s)) { 1140 overflow = 1; 1141 event->pmu->stop(event, 0); 1142 } 1143 perf_event_update_userpage(event); 1144 out: 1145 return overflow; 1146 } 1147 1148 static void perf_event_count_update(struct perf_event *event, u64 count) 1149 { 1150 local64_add(count, &event->count); 1151 } 1152 1153 /* hw_collect_samples() - Walk through a sample-data-block and collect samples 1154 * @event: The perf event 1155 * @sdbt: Sample-data-block table 1156 * @overflow: Event overflow counter 1157 * 1158 * Walks through a sample-data-block and collects sampling data entries that are 1159 * then pushed to the perf event subsystem. Depending on the sampling function, 1160 * there can be either basic-sampling or combined-sampling data entries. A 1161 * combined-sampling data entry consists of a basic- and a diagnostic-sampling 1162 * data entry. The sampling function is determined by the flags in the perf 1163 * event hardware structure. The function always works with a combined-sampling 1164 * data entry but ignores the the diagnostic portion if it is not available. 1165 * 1166 * Note that the implementation focuses on basic-sampling data entries and, if 1167 * such an entry is not valid, the entire combined-sampling data entry is 1168 * ignored. 1169 * 1170 * The overflow variables counts the number of samples that has been discarded 1171 * due to a perf event overflow. 1172 */ 1173 static void hw_collect_samples(struct perf_event *event, unsigned long *sdbt, 1174 unsigned long long *overflow) 1175 { 1176 struct hws_trailer_entry *te; 1177 struct hws_basic_entry *sample; 1178 1179 te = (struct hws_trailer_entry *) trailer_entry_ptr(*sdbt); 1180 sample = (struct hws_basic_entry *) *sdbt; 1181 while ((unsigned long *) sample < (unsigned long *) te) { 1182 /* Check for an empty sample */ 1183 if (!sample->def || sample->LS) 1184 break; 1185 1186 /* Update perf event period */ 1187 perf_event_count_update(event, SAMPL_RATE(&event->hw)); 1188 1189 /* Check whether sample is valid */ 1190 if (sample->def == 0x0001) { 1191 /* If an event overflow occurred, the PMU is stopped to 1192 * throttle event delivery. Remaining sample data is 1193 * discarded. 1194 */ 1195 if (!*overflow) { 1196 /* Check whether sample is consistent */ 1197 if (sample->I == 0 && sample->W == 0) { 1198 /* Deliver sample data to perf */ 1199 *overflow = perf_push_sample(event, 1200 sample); 1201 } 1202 } else 1203 /* Count discarded samples */ 1204 *overflow += 1; 1205 } else { 1206 debug_sprintf_event(sfdbg, 4, 1207 "%s: Found unknown" 1208 " sampling data entry: te->f %i" 1209 " basic.def %#4x (%p)\n", __func__, 1210 te->header.f, sample->def, sample); 1211 /* Sample slot is not yet written or other record. 1212 * 1213 * This condition can occur if the buffer was reused 1214 * from a combined basic- and diagnostic-sampling. 1215 * If only basic-sampling is then active, entries are 1216 * written into the larger diagnostic entries. 1217 * This is typically the case for sample-data-blocks 1218 * that are not full. Stop processing if the first 1219 * invalid format was detected. 1220 */ 1221 if (!te->header.f) 1222 break; 1223 } 1224 1225 /* Reset sample slot and advance to next sample */ 1226 sample->def = 0; 1227 sample++; 1228 } 1229 } 1230 1231 static inline __uint128_t __cdsg(__uint128_t *ptr, __uint128_t old, __uint128_t new) 1232 { 1233 asm volatile( 1234 " cdsg %[old],%[new],%[ptr]\n" 1235 : [old] "+d" (old), [ptr] "+QS" (*ptr) 1236 : [new] "d" (new) 1237 : "memory", "cc"); 1238 return old; 1239 } 1240 1241 /* hw_perf_event_update() - Process sampling buffer 1242 * @event: The perf event 1243 * @flush_all: Flag to also flush partially filled sample-data-blocks 1244 * 1245 * Processes the sampling buffer and create perf event samples. 1246 * The sampling buffer position are retrieved and saved in the TEAR_REG 1247 * register of the specified perf event. 1248 * 1249 * Only full sample-data-blocks are processed. Specify the flash_all flag 1250 * to also walk through partially filled sample-data-blocks. It is ignored 1251 * if PERF_CPUM_SF_FULL_BLOCKS is set. The PERF_CPUM_SF_FULL_BLOCKS flag 1252 * enforces the processing of full sample-data-blocks only (trailer entries 1253 * with the block-full-indicator bit set). 1254 */ 1255 static void hw_perf_event_update(struct perf_event *event, int flush_all) 1256 { 1257 unsigned long long event_overflow, sampl_overflow, num_sdb; 1258 union hws_trailer_header old, prev, new; 1259 struct hw_perf_event *hwc = &event->hw; 1260 struct hws_trailer_entry *te; 1261 unsigned long *sdbt; 1262 int done; 1263 1264 /* 1265 * AUX buffer is used when in diagnostic sampling mode. 1266 * No perf events/samples are created. 1267 */ 1268 if (SAMPL_DIAG_MODE(&event->hw)) 1269 return; 1270 1271 if (flush_all && SDB_FULL_BLOCKS(hwc)) 1272 flush_all = 0; 1273 1274 sdbt = (unsigned long *) TEAR_REG(hwc); 1275 done = event_overflow = sampl_overflow = num_sdb = 0; 1276 while (!done) { 1277 /* Get the trailer entry of the sample-data-block */ 1278 te = (struct hws_trailer_entry *) trailer_entry_ptr(*sdbt); 1279 1280 /* Leave loop if no more work to do (block full indicator) */ 1281 if (!te->header.f) { 1282 done = 1; 1283 if (!flush_all) 1284 break; 1285 } 1286 1287 /* Check the sample overflow count */ 1288 if (te->header.overflow) 1289 /* Account sample overflows and, if a particular limit 1290 * is reached, extend the sampling buffer. 1291 * For details, see sfb_account_overflows(). 1292 */ 1293 sampl_overflow += te->header.overflow; 1294 1295 /* Timestamps are valid for full sample-data-blocks only */ 1296 debug_sprintf_event(sfdbg, 6, "%s: sdbt %#lx " 1297 "overflow %llu timestamp %#llx\n", 1298 __func__, (unsigned long)sdbt, te->header.overflow, 1299 (te->header.f) ? trailer_timestamp(te) : 0ULL); 1300 1301 /* Collect all samples from a single sample-data-block and 1302 * flag if an (perf) event overflow happened. If so, the PMU 1303 * is stopped and remaining samples will be discarded. 1304 */ 1305 hw_collect_samples(event, sdbt, &event_overflow); 1306 num_sdb++; 1307 1308 /* Reset trailer (using compare-double-and-swap) */ 1309 /* READ_ONCE() 16 byte header */ 1310 prev.val = __cdsg(&te->header.val, 0, 0); 1311 do { 1312 old.val = prev.val; 1313 new.val = prev.val; 1314 new.f = 0; 1315 new.a = 1; 1316 new.overflow = 0; 1317 prev.val = __cdsg(&te->header.val, old.val, new.val); 1318 } while (prev.val != old.val); 1319 1320 /* Advance to next sample-data-block */ 1321 sdbt++; 1322 if (is_link_entry(sdbt)) 1323 sdbt = get_next_sdbt(sdbt); 1324 1325 /* Update event hardware registers */ 1326 TEAR_REG(hwc) = (unsigned long) sdbt; 1327 1328 /* Stop processing sample-data if all samples of the current 1329 * sample-data-block were flushed even if it was not full. 1330 */ 1331 if (flush_all && done) 1332 break; 1333 } 1334 1335 /* Account sample overflows in the event hardware structure */ 1336 if (sampl_overflow) 1337 OVERFLOW_REG(hwc) = DIV_ROUND_UP(OVERFLOW_REG(hwc) + 1338 sampl_overflow, 1 + num_sdb); 1339 1340 /* Perf_event_overflow() and perf_event_account_interrupt() limit 1341 * the interrupt rate to an upper limit. Roughly 1000 samples per 1342 * task tick. 1343 * Hitting this limit results in a large number 1344 * of throttled REF_REPORT_THROTTLE entries and the samples 1345 * are dropped. 1346 * Slightly increase the interval to avoid hitting this limit. 1347 */ 1348 if (event_overflow) { 1349 SAMPL_RATE(hwc) += DIV_ROUND_UP(SAMPL_RATE(hwc), 10); 1350 debug_sprintf_event(sfdbg, 1, "%s: rate adjustment %ld\n", 1351 __func__, 1352 DIV_ROUND_UP(SAMPL_RATE(hwc), 10)); 1353 } 1354 1355 if (sampl_overflow || event_overflow) 1356 debug_sprintf_event(sfdbg, 4, "%s: " 1357 "overflows: sample %llu event %llu" 1358 " total %llu num_sdb %llu\n", 1359 __func__, sampl_overflow, event_overflow, 1360 OVERFLOW_REG(hwc), num_sdb); 1361 } 1362 1363 #define AUX_SDB_INDEX(aux, i) ((i) % aux->sfb.num_sdb) 1364 #define AUX_SDB_NUM(aux, start, end) (end >= start ? end - start + 1 : 0) 1365 #define AUX_SDB_NUM_ALERT(aux) AUX_SDB_NUM(aux, aux->head, aux->alert_mark) 1366 #define AUX_SDB_NUM_EMPTY(aux) AUX_SDB_NUM(aux, aux->head, aux->empty_mark) 1367 1368 /* 1369 * Get trailer entry by index of SDB. 1370 */ 1371 static struct hws_trailer_entry *aux_sdb_trailer(struct aux_buffer *aux, 1372 unsigned long index) 1373 { 1374 unsigned long sdb; 1375 1376 index = AUX_SDB_INDEX(aux, index); 1377 sdb = aux->sdb_index[index]; 1378 return (struct hws_trailer_entry *)trailer_entry_ptr(sdb); 1379 } 1380 1381 /* 1382 * Finish sampling on the cpu. Called by cpumsf_pmu_del() with pmu 1383 * disabled. Collect the full SDBs in AUX buffer which have not reached 1384 * the point of alert indicator. And ignore the SDBs which are not 1385 * full. 1386 * 1387 * 1. Scan SDBs to see how much data is there and consume them. 1388 * 2. Remove alert indicator in the buffer. 1389 */ 1390 static void aux_output_end(struct perf_output_handle *handle) 1391 { 1392 unsigned long i, range_scan, idx; 1393 struct aux_buffer *aux; 1394 struct hws_trailer_entry *te; 1395 1396 aux = perf_get_aux(handle); 1397 if (!aux) 1398 return; 1399 1400 range_scan = AUX_SDB_NUM_ALERT(aux); 1401 for (i = 0, idx = aux->head; i < range_scan; i++, idx++) { 1402 te = aux_sdb_trailer(aux, idx); 1403 if (!te->header.f) 1404 break; 1405 } 1406 /* i is num of SDBs which are full */ 1407 perf_aux_output_end(handle, i << PAGE_SHIFT); 1408 1409 /* Remove alert indicators in the buffer */ 1410 te = aux_sdb_trailer(aux, aux->alert_mark); 1411 te->header.a = 0; 1412 1413 debug_sprintf_event(sfdbg, 6, "%s: SDBs %ld range %ld head %ld\n", 1414 __func__, i, range_scan, aux->head); 1415 } 1416 1417 /* 1418 * Start sampling on the CPU. Called by cpumsf_pmu_add() when an event 1419 * is first added to the CPU or rescheduled again to the CPU. It is called 1420 * with pmu disabled. 1421 * 1422 * 1. Reset the trailer of SDBs to get ready for new data. 1423 * 2. Tell the hardware where to put the data by reset the SDBs buffer 1424 * head(tear/dear). 1425 */ 1426 static int aux_output_begin(struct perf_output_handle *handle, 1427 struct aux_buffer *aux, 1428 struct cpu_hw_sf *cpuhw) 1429 { 1430 unsigned long range; 1431 unsigned long i, range_scan, idx; 1432 unsigned long head, base, offset; 1433 struct hws_trailer_entry *te; 1434 1435 if (WARN_ON_ONCE(handle->head & ~PAGE_MASK)) 1436 return -EINVAL; 1437 1438 aux->head = handle->head >> PAGE_SHIFT; 1439 range = (handle->size + 1) >> PAGE_SHIFT; 1440 if (range <= 1) 1441 return -ENOMEM; 1442 1443 /* 1444 * SDBs between aux->head and aux->empty_mark are already ready 1445 * for new data. range_scan is num of SDBs not within them. 1446 */ 1447 debug_sprintf_event(sfdbg, 6, 1448 "%s: range %ld head %ld alert %ld empty %ld\n", 1449 __func__, range, aux->head, aux->alert_mark, 1450 aux->empty_mark); 1451 if (range > AUX_SDB_NUM_EMPTY(aux)) { 1452 range_scan = range - AUX_SDB_NUM_EMPTY(aux); 1453 idx = aux->empty_mark + 1; 1454 for (i = 0; i < range_scan; i++, idx++) { 1455 te = aux_sdb_trailer(aux, idx); 1456 te->header.f = 0; 1457 te->header.a = 0; 1458 te->header.overflow = 0; 1459 } 1460 /* Save the position of empty SDBs */ 1461 aux->empty_mark = aux->head + range - 1; 1462 } 1463 1464 /* Set alert indicator */ 1465 aux->alert_mark = aux->head + range/2 - 1; 1466 te = aux_sdb_trailer(aux, aux->alert_mark); 1467 te->header.a = 1; 1468 1469 /* Reset hardware buffer head */ 1470 head = AUX_SDB_INDEX(aux, aux->head); 1471 base = aux->sdbt_index[head / CPUM_SF_SDB_PER_TABLE]; 1472 offset = head % CPUM_SF_SDB_PER_TABLE; 1473 cpuhw->lsctl.tear = base + offset * sizeof(unsigned long); 1474 cpuhw->lsctl.dear = aux->sdb_index[head]; 1475 1476 debug_sprintf_event(sfdbg, 6, "%s: head %ld alert %ld empty %ld " 1477 "index %ld tear %#lx dear %#lx\n", __func__, 1478 aux->head, aux->alert_mark, aux->empty_mark, 1479 head / CPUM_SF_SDB_PER_TABLE, 1480 cpuhw->lsctl.tear, cpuhw->lsctl.dear); 1481 1482 return 0; 1483 } 1484 1485 /* 1486 * Set alert indicator on SDB at index @alert_index while sampler is running. 1487 * 1488 * Return true if successfully. 1489 * Return false if full indicator is already set by hardware sampler. 1490 */ 1491 static bool aux_set_alert(struct aux_buffer *aux, unsigned long alert_index, 1492 unsigned long long *overflow) 1493 { 1494 union hws_trailer_header old, prev, new; 1495 struct hws_trailer_entry *te; 1496 1497 te = aux_sdb_trailer(aux, alert_index); 1498 /* READ_ONCE() 16 byte header */ 1499 prev.val = __cdsg(&te->header.val, 0, 0); 1500 do { 1501 old.val = prev.val; 1502 new.val = prev.val; 1503 *overflow = old.overflow; 1504 if (old.f) { 1505 /* 1506 * SDB is already set by hardware. 1507 * Abort and try to set somewhere 1508 * behind. 1509 */ 1510 return false; 1511 } 1512 new.a = 1; 1513 new.overflow = 0; 1514 prev.val = __cdsg(&te->header.val, old.val, new.val); 1515 } while (prev.val != old.val); 1516 return true; 1517 } 1518 1519 /* 1520 * aux_reset_buffer() - Scan and setup SDBs for new samples 1521 * @aux: The AUX buffer to set 1522 * @range: The range of SDBs to scan started from aux->head 1523 * @overflow: Set to overflow count 1524 * 1525 * Set alert indicator on the SDB at index of aux->alert_mark. If this SDB is 1526 * marked as empty, check if it is already set full by the hardware sampler. 1527 * If yes, that means new data is already there before we can set an alert 1528 * indicator. Caller should try to set alert indicator to some position behind. 1529 * 1530 * Scan the SDBs in AUX buffer from behind aux->empty_mark. They are used 1531 * previously and have already been consumed by user space. Reset these SDBs 1532 * (clear full indicator and alert indicator) for new data. 1533 * If aux->alert_mark fall in this area, just set it. Overflow count is 1534 * recorded while scanning. 1535 * 1536 * SDBs between aux->head and aux->empty_mark are already reset at last time. 1537 * and ready for new samples. So scanning on this area could be skipped. 1538 * 1539 * Return true if alert indicator is set successfully and false if not. 1540 */ 1541 static bool aux_reset_buffer(struct aux_buffer *aux, unsigned long range, 1542 unsigned long long *overflow) 1543 { 1544 unsigned long i, range_scan, idx, idx_old; 1545 union hws_trailer_header old, prev, new; 1546 unsigned long long orig_overflow; 1547 struct hws_trailer_entry *te; 1548 1549 debug_sprintf_event(sfdbg, 6, "%s: range %ld head %ld alert %ld " 1550 "empty %ld\n", __func__, range, aux->head, 1551 aux->alert_mark, aux->empty_mark); 1552 if (range <= AUX_SDB_NUM_EMPTY(aux)) 1553 /* 1554 * No need to scan. All SDBs in range are marked as empty. 1555 * Just set alert indicator. Should check race with hardware 1556 * sampler. 1557 */ 1558 return aux_set_alert(aux, aux->alert_mark, overflow); 1559 1560 if (aux->alert_mark <= aux->empty_mark) 1561 /* 1562 * Set alert indicator on empty SDB. Should check race 1563 * with hardware sampler. 1564 */ 1565 if (!aux_set_alert(aux, aux->alert_mark, overflow)) 1566 return false; 1567 1568 /* 1569 * Scan the SDBs to clear full and alert indicator used previously. 1570 * Start scanning from one SDB behind empty_mark. If the new alert 1571 * indicator fall into this range, set it. 1572 */ 1573 range_scan = range - AUX_SDB_NUM_EMPTY(aux); 1574 idx_old = idx = aux->empty_mark + 1; 1575 for (i = 0; i < range_scan; i++, idx++) { 1576 te = aux_sdb_trailer(aux, idx); 1577 /* READ_ONCE() 16 byte header */ 1578 prev.val = __cdsg(&te->header.val, 0, 0); 1579 do { 1580 old.val = prev.val; 1581 new.val = prev.val; 1582 orig_overflow = old.overflow; 1583 new.f = 0; 1584 new.overflow = 0; 1585 if (idx == aux->alert_mark) 1586 new.a = 1; 1587 else 1588 new.a = 0; 1589 prev.val = __cdsg(&te->header.val, old.val, new.val); 1590 } while (prev.val != old.val); 1591 *overflow += orig_overflow; 1592 } 1593 1594 /* Update empty_mark to new position */ 1595 aux->empty_mark = aux->head + range - 1; 1596 1597 debug_sprintf_event(sfdbg, 6, "%s: range_scan %ld idx %ld..%ld " 1598 "empty %ld\n", __func__, range_scan, idx_old, 1599 idx - 1, aux->empty_mark); 1600 return true; 1601 } 1602 1603 /* 1604 * Measurement alert handler for diagnostic mode sampling. 1605 */ 1606 static void hw_collect_aux(struct cpu_hw_sf *cpuhw) 1607 { 1608 struct aux_buffer *aux; 1609 int done = 0; 1610 unsigned long range = 0, size; 1611 unsigned long long overflow = 0; 1612 struct perf_output_handle *handle = &cpuhw->handle; 1613 unsigned long num_sdb; 1614 1615 aux = perf_get_aux(handle); 1616 if (WARN_ON_ONCE(!aux)) 1617 return; 1618 1619 /* Inform user space new data arrived */ 1620 size = AUX_SDB_NUM_ALERT(aux) << PAGE_SHIFT; 1621 debug_sprintf_event(sfdbg, 6, "%s: #alert %ld\n", __func__, 1622 size >> PAGE_SHIFT); 1623 perf_aux_output_end(handle, size); 1624 1625 num_sdb = aux->sfb.num_sdb; 1626 while (!done) { 1627 /* Get an output handle */ 1628 aux = perf_aux_output_begin(handle, cpuhw->event); 1629 if (handle->size == 0) { 1630 pr_err("The AUX buffer with %lu pages for the " 1631 "diagnostic-sampling mode is full\n", 1632 num_sdb); 1633 debug_sprintf_event(sfdbg, 1, 1634 "%s: AUX buffer used up\n", 1635 __func__); 1636 break; 1637 } 1638 if (WARN_ON_ONCE(!aux)) 1639 return; 1640 1641 /* Update head and alert_mark to new position */ 1642 aux->head = handle->head >> PAGE_SHIFT; 1643 range = (handle->size + 1) >> PAGE_SHIFT; 1644 if (range == 1) 1645 aux->alert_mark = aux->head; 1646 else 1647 aux->alert_mark = aux->head + range/2 - 1; 1648 1649 if (aux_reset_buffer(aux, range, &overflow)) { 1650 if (!overflow) { 1651 done = 1; 1652 break; 1653 } 1654 size = range << PAGE_SHIFT; 1655 perf_aux_output_end(&cpuhw->handle, size); 1656 pr_err("Sample data caused the AUX buffer with %lu " 1657 "pages to overflow\n", aux->sfb.num_sdb); 1658 debug_sprintf_event(sfdbg, 1, "%s: head %ld range %ld " 1659 "overflow %lld\n", __func__, 1660 aux->head, range, overflow); 1661 } else { 1662 size = AUX_SDB_NUM_ALERT(aux) << PAGE_SHIFT; 1663 perf_aux_output_end(&cpuhw->handle, size); 1664 debug_sprintf_event(sfdbg, 6, "%s: head %ld alert %ld " 1665 "already full, try another\n", 1666 __func__, 1667 aux->head, aux->alert_mark); 1668 } 1669 } 1670 1671 if (done) 1672 debug_sprintf_event(sfdbg, 6, "%s: head %ld alert %ld " 1673 "empty %ld\n", __func__, aux->head, 1674 aux->alert_mark, aux->empty_mark); 1675 } 1676 1677 /* 1678 * Callback when freeing AUX buffers. 1679 */ 1680 static void aux_buffer_free(void *data) 1681 { 1682 struct aux_buffer *aux = data; 1683 unsigned long i, num_sdbt; 1684 1685 if (!aux) 1686 return; 1687 1688 /* Free SDBT. SDB is freed by the caller */ 1689 num_sdbt = aux->sfb.num_sdbt; 1690 for (i = 0; i < num_sdbt; i++) 1691 free_page(aux->sdbt_index[i]); 1692 1693 kfree(aux->sdbt_index); 1694 kfree(aux->sdb_index); 1695 kfree(aux); 1696 1697 debug_sprintf_event(sfdbg, 4, "%s: SDBTs %lu\n", __func__, num_sdbt); 1698 } 1699 1700 static void aux_sdb_init(unsigned long sdb) 1701 { 1702 struct hws_trailer_entry *te; 1703 1704 te = (struct hws_trailer_entry *)trailer_entry_ptr(sdb); 1705 1706 /* Save clock base */ 1707 te->clock_base = 1; 1708 te->progusage2 = tod_clock_base.tod; 1709 } 1710 1711 /* 1712 * aux_buffer_setup() - Setup AUX buffer for diagnostic mode sampling 1713 * @event: Event the buffer is setup for, event->cpu == -1 means current 1714 * @pages: Array of pointers to buffer pages passed from perf core 1715 * @nr_pages: Total pages 1716 * @snapshot: Flag for snapshot mode 1717 * 1718 * This is the callback when setup an event using AUX buffer. Perf tool can 1719 * trigger this by an additional mmap() call on the event. Unlike the buffer 1720 * for basic samples, AUX buffer belongs to the event. It is scheduled with 1721 * the task among online cpus when it is a per-thread event. 1722 * 1723 * Return the private AUX buffer structure if success or NULL if fails. 1724 */ 1725 static void *aux_buffer_setup(struct perf_event *event, void **pages, 1726 int nr_pages, bool snapshot) 1727 { 1728 struct sf_buffer *sfb; 1729 struct aux_buffer *aux; 1730 unsigned long *new, *tail; 1731 int i, n_sdbt; 1732 1733 if (!nr_pages || !pages) 1734 return NULL; 1735 1736 if (nr_pages > CPUM_SF_MAX_SDB * CPUM_SF_SDB_DIAG_FACTOR) { 1737 pr_err("AUX buffer size (%i pages) is larger than the " 1738 "maximum sampling buffer limit\n", 1739 nr_pages); 1740 return NULL; 1741 } else if (nr_pages < CPUM_SF_MIN_SDB * CPUM_SF_SDB_DIAG_FACTOR) { 1742 pr_err("AUX buffer size (%i pages) is less than the " 1743 "minimum sampling buffer limit\n", 1744 nr_pages); 1745 return NULL; 1746 } 1747 1748 /* Allocate aux_buffer struct for the event */ 1749 aux = kzalloc(sizeof(struct aux_buffer), GFP_KERNEL); 1750 if (!aux) 1751 goto no_aux; 1752 sfb = &aux->sfb; 1753 1754 /* Allocate sdbt_index for fast reference */ 1755 n_sdbt = DIV_ROUND_UP(nr_pages, CPUM_SF_SDB_PER_TABLE); 1756 aux->sdbt_index = kmalloc_array(n_sdbt, sizeof(void *), GFP_KERNEL); 1757 if (!aux->sdbt_index) 1758 goto no_sdbt_index; 1759 1760 /* Allocate sdb_index for fast reference */ 1761 aux->sdb_index = kmalloc_array(nr_pages, sizeof(void *), GFP_KERNEL); 1762 if (!aux->sdb_index) 1763 goto no_sdb_index; 1764 1765 /* Allocate the first SDBT */ 1766 sfb->num_sdbt = 0; 1767 sfb->sdbt = (unsigned long *) get_zeroed_page(GFP_KERNEL); 1768 if (!sfb->sdbt) 1769 goto no_sdbt; 1770 aux->sdbt_index[sfb->num_sdbt++] = (unsigned long)sfb->sdbt; 1771 tail = sfb->tail = sfb->sdbt; 1772 1773 /* 1774 * Link the provided pages of AUX buffer to SDBT. 1775 * Allocate SDBT if needed. 1776 */ 1777 for (i = 0; i < nr_pages; i++, tail++) { 1778 if (require_table_link(tail)) { 1779 new = (unsigned long *) get_zeroed_page(GFP_KERNEL); 1780 if (!new) 1781 goto no_sdbt; 1782 aux->sdbt_index[sfb->num_sdbt++] = (unsigned long)new; 1783 /* Link current page to tail of chain */ 1784 *tail = (unsigned long)(void *) new + 1; 1785 tail = new; 1786 } 1787 /* Tail is the entry in a SDBT */ 1788 *tail = (unsigned long)pages[i]; 1789 aux->sdb_index[i] = (unsigned long)pages[i]; 1790 aux_sdb_init((unsigned long)pages[i]); 1791 } 1792 sfb->num_sdb = nr_pages; 1793 1794 /* Link the last entry in the SDBT to the first SDBT */ 1795 *tail = (unsigned long) sfb->sdbt + 1; 1796 sfb->tail = tail; 1797 1798 /* 1799 * Initial all SDBs are zeroed. Mark it as empty. 1800 * So there is no need to clear the full indicator 1801 * when this event is first added. 1802 */ 1803 aux->empty_mark = sfb->num_sdb - 1; 1804 1805 debug_sprintf_event(sfdbg, 4, "%s: SDBTs %lu SDBs %lu\n", __func__, 1806 sfb->num_sdbt, sfb->num_sdb); 1807 1808 return aux; 1809 1810 no_sdbt: 1811 /* SDBs (AUX buffer pages) are freed by caller */ 1812 for (i = 0; i < sfb->num_sdbt; i++) 1813 free_page(aux->sdbt_index[i]); 1814 kfree(aux->sdb_index); 1815 no_sdb_index: 1816 kfree(aux->sdbt_index); 1817 no_sdbt_index: 1818 kfree(aux); 1819 no_aux: 1820 return NULL; 1821 } 1822 1823 static void cpumsf_pmu_read(struct perf_event *event) 1824 { 1825 /* Nothing to do ... updates are interrupt-driven */ 1826 } 1827 1828 /* Check if the new sampling period/freqeuncy is appropriate. 1829 * 1830 * Return non-zero on error and zero on passed checks. 1831 */ 1832 static int cpumsf_pmu_check_period(struct perf_event *event, u64 value) 1833 { 1834 struct hws_qsi_info_block si; 1835 unsigned long rate; 1836 bool do_freq; 1837 1838 memset(&si, 0, sizeof(si)); 1839 if (event->cpu == -1) { 1840 if (qsi(&si)) 1841 return -ENODEV; 1842 } else { 1843 /* Event is pinned to a particular CPU, retrieve the per-CPU 1844 * sampling structure for accessing the CPU-specific QSI. 1845 */ 1846 struct cpu_hw_sf *cpuhw = &per_cpu(cpu_hw_sf, event->cpu); 1847 1848 si = cpuhw->qsi; 1849 } 1850 1851 do_freq = !!SAMPLE_FREQ_MODE(&event->hw); 1852 rate = getrate(do_freq, value, &si); 1853 if (!rate) 1854 return -EINVAL; 1855 1856 event->attr.sample_period = rate; 1857 SAMPL_RATE(&event->hw) = rate; 1858 hw_init_period(&event->hw, SAMPL_RATE(&event->hw)); 1859 debug_sprintf_event(sfdbg, 4, "%s:" 1860 " cpu %d value %#llx period %#llx freq %d\n", 1861 __func__, event->cpu, value, 1862 event->attr.sample_period, do_freq); 1863 return 0; 1864 } 1865 1866 /* Activate sampling control. 1867 * Next call of pmu_enable() starts sampling. 1868 */ 1869 static void cpumsf_pmu_start(struct perf_event *event, int flags) 1870 { 1871 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 1872 1873 if (WARN_ON_ONCE(!(event->hw.state & PERF_HES_STOPPED))) 1874 return; 1875 1876 if (flags & PERF_EF_RELOAD) 1877 WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE)); 1878 1879 perf_pmu_disable(event->pmu); 1880 event->hw.state = 0; 1881 cpuhw->lsctl.cs = 1; 1882 if (SAMPL_DIAG_MODE(&event->hw)) 1883 cpuhw->lsctl.cd = 1; 1884 perf_pmu_enable(event->pmu); 1885 } 1886 1887 /* Deactivate sampling control. 1888 * Next call of pmu_enable() stops sampling. 1889 */ 1890 static void cpumsf_pmu_stop(struct perf_event *event, int flags) 1891 { 1892 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 1893 1894 if (event->hw.state & PERF_HES_STOPPED) 1895 return; 1896 1897 perf_pmu_disable(event->pmu); 1898 cpuhw->lsctl.cs = 0; 1899 cpuhw->lsctl.cd = 0; 1900 event->hw.state |= PERF_HES_STOPPED; 1901 1902 if ((flags & PERF_EF_UPDATE) && !(event->hw.state & PERF_HES_UPTODATE)) { 1903 hw_perf_event_update(event, 1); 1904 event->hw.state |= PERF_HES_UPTODATE; 1905 } 1906 perf_pmu_enable(event->pmu); 1907 } 1908 1909 static int cpumsf_pmu_add(struct perf_event *event, int flags) 1910 { 1911 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 1912 struct aux_buffer *aux; 1913 int err; 1914 1915 if (cpuhw->flags & PMU_F_IN_USE) 1916 return -EAGAIN; 1917 1918 if (!SAMPL_DIAG_MODE(&event->hw) && !cpuhw->sfb.sdbt) 1919 return -EINVAL; 1920 1921 err = 0; 1922 perf_pmu_disable(event->pmu); 1923 1924 event->hw.state = PERF_HES_UPTODATE | PERF_HES_STOPPED; 1925 1926 /* Set up sampling controls. Always program the sampling register 1927 * using the SDB-table start. Reset TEAR_REG event hardware register 1928 * that is used by hw_perf_event_update() to store the sampling buffer 1929 * position after samples have been flushed. 1930 */ 1931 cpuhw->lsctl.s = 0; 1932 cpuhw->lsctl.h = 1; 1933 cpuhw->lsctl.interval = SAMPL_RATE(&event->hw); 1934 if (!SAMPL_DIAG_MODE(&event->hw)) { 1935 cpuhw->lsctl.tear = (unsigned long) cpuhw->sfb.sdbt; 1936 cpuhw->lsctl.dear = *(unsigned long *) cpuhw->sfb.sdbt; 1937 TEAR_REG(&event->hw) = (unsigned long) cpuhw->sfb.sdbt; 1938 } 1939 1940 /* Ensure sampling functions are in the disabled state. If disabled, 1941 * switch on sampling enable control. */ 1942 if (WARN_ON_ONCE(cpuhw->lsctl.es == 1 || cpuhw->lsctl.ed == 1)) { 1943 err = -EAGAIN; 1944 goto out; 1945 } 1946 if (SAMPL_DIAG_MODE(&event->hw)) { 1947 aux = perf_aux_output_begin(&cpuhw->handle, event); 1948 if (!aux) { 1949 err = -EINVAL; 1950 goto out; 1951 } 1952 err = aux_output_begin(&cpuhw->handle, aux, cpuhw); 1953 if (err) 1954 goto out; 1955 cpuhw->lsctl.ed = 1; 1956 } 1957 cpuhw->lsctl.es = 1; 1958 1959 /* Set in_use flag and store event */ 1960 cpuhw->event = event; 1961 cpuhw->flags |= PMU_F_IN_USE; 1962 1963 if (flags & PERF_EF_START) 1964 cpumsf_pmu_start(event, PERF_EF_RELOAD); 1965 out: 1966 perf_event_update_userpage(event); 1967 perf_pmu_enable(event->pmu); 1968 return err; 1969 } 1970 1971 static void cpumsf_pmu_del(struct perf_event *event, int flags) 1972 { 1973 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 1974 1975 perf_pmu_disable(event->pmu); 1976 cpumsf_pmu_stop(event, PERF_EF_UPDATE); 1977 1978 cpuhw->lsctl.es = 0; 1979 cpuhw->lsctl.ed = 0; 1980 cpuhw->flags &= ~PMU_F_IN_USE; 1981 cpuhw->event = NULL; 1982 1983 if (SAMPL_DIAG_MODE(&event->hw)) 1984 aux_output_end(&cpuhw->handle); 1985 perf_event_update_userpage(event); 1986 perf_pmu_enable(event->pmu); 1987 } 1988 1989 CPUMF_EVENT_ATTR(SF, SF_CYCLES_BASIC, PERF_EVENT_CPUM_SF); 1990 CPUMF_EVENT_ATTR(SF, SF_CYCLES_BASIC_DIAG, PERF_EVENT_CPUM_SF_DIAG); 1991 1992 /* Attribute list for CPU_SF. 1993 * 1994 * The availablitiy depends on the CPU_MF sampling facility authorization 1995 * for basic + diagnositic samples. This is determined at initialization 1996 * time by the sampling facility device driver. 1997 * If the authorization for basic samples is turned off, it should be 1998 * also turned off for diagnostic sampling. 1999 * 2000 * During initialization of the device driver, check the authorization 2001 * level for diagnostic sampling and installs the attribute 2002 * file for diagnostic sampling if necessary. 2003 * 2004 * For now install a placeholder to reference all possible attributes: 2005 * SF_CYCLES_BASIC and SF_CYCLES_BASIC_DIAG. 2006 * Add another entry for the final NULL pointer. 2007 */ 2008 enum { 2009 SF_CYCLES_BASIC_ATTR_IDX = 0, 2010 SF_CYCLES_BASIC_DIAG_ATTR_IDX, 2011 SF_CYCLES_ATTR_MAX 2012 }; 2013 2014 static struct attribute *cpumsf_pmu_events_attr[SF_CYCLES_ATTR_MAX + 1] = { 2015 [SF_CYCLES_BASIC_ATTR_IDX] = CPUMF_EVENT_PTR(SF, SF_CYCLES_BASIC) 2016 }; 2017 2018 PMU_FORMAT_ATTR(event, "config:0-63"); 2019 2020 static struct attribute *cpumsf_pmu_format_attr[] = { 2021 &format_attr_event.attr, 2022 NULL, 2023 }; 2024 2025 static struct attribute_group cpumsf_pmu_events_group = { 2026 .name = "events", 2027 .attrs = cpumsf_pmu_events_attr, 2028 }; 2029 2030 static struct attribute_group cpumsf_pmu_format_group = { 2031 .name = "format", 2032 .attrs = cpumsf_pmu_format_attr, 2033 }; 2034 2035 static const struct attribute_group *cpumsf_pmu_attr_groups[] = { 2036 &cpumsf_pmu_events_group, 2037 &cpumsf_pmu_format_group, 2038 NULL, 2039 }; 2040 2041 static struct pmu cpumf_sampling = { 2042 .pmu_enable = cpumsf_pmu_enable, 2043 .pmu_disable = cpumsf_pmu_disable, 2044 2045 .event_init = cpumsf_pmu_event_init, 2046 .add = cpumsf_pmu_add, 2047 .del = cpumsf_pmu_del, 2048 2049 .start = cpumsf_pmu_start, 2050 .stop = cpumsf_pmu_stop, 2051 .read = cpumsf_pmu_read, 2052 2053 .attr_groups = cpumsf_pmu_attr_groups, 2054 2055 .setup_aux = aux_buffer_setup, 2056 .free_aux = aux_buffer_free, 2057 2058 .check_period = cpumsf_pmu_check_period, 2059 }; 2060 2061 static void cpumf_measurement_alert(struct ext_code ext_code, 2062 unsigned int alert, unsigned long unused) 2063 { 2064 struct cpu_hw_sf *cpuhw; 2065 2066 if (!(alert & CPU_MF_INT_SF_MASK)) 2067 return; 2068 inc_irq_stat(IRQEXT_CMS); 2069 cpuhw = this_cpu_ptr(&cpu_hw_sf); 2070 2071 /* Measurement alerts are shared and might happen when the PMU 2072 * is not reserved. Ignore these alerts in this case. */ 2073 if (!(cpuhw->flags & PMU_F_RESERVED)) 2074 return; 2075 2076 /* The processing below must take care of multiple alert events that 2077 * might be indicated concurrently. */ 2078 2079 /* Program alert request */ 2080 if (alert & CPU_MF_INT_SF_PRA) { 2081 if (cpuhw->flags & PMU_F_IN_USE) 2082 if (SAMPL_DIAG_MODE(&cpuhw->event->hw)) 2083 hw_collect_aux(cpuhw); 2084 else 2085 hw_perf_event_update(cpuhw->event, 0); 2086 else 2087 WARN_ON_ONCE(!(cpuhw->flags & PMU_F_IN_USE)); 2088 } 2089 2090 /* Report measurement alerts only for non-PRA codes */ 2091 if (alert != CPU_MF_INT_SF_PRA) 2092 debug_sprintf_event(sfdbg, 6, "%s: alert %#x\n", __func__, 2093 alert); 2094 2095 /* Sampling authorization change request */ 2096 if (alert & CPU_MF_INT_SF_SACA) 2097 qsi(&cpuhw->qsi); 2098 2099 /* Loss of sample data due to high-priority machine activities */ 2100 if (alert & CPU_MF_INT_SF_LSDA) { 2101 pr_err("Sample data was lost\n"); 2102 cpuhw->flags |= PMU_F_ERR_LSDA; 2103 sf_disable(); 2104 } 2105 2106 /* Invalid sampling buffer entry */ 2107 if (alert & (CPU_MF_INT_SF_IAE|CPU_MF_INT_SF_ISE)) { 2108 pr_err("A sampling buffer entry is incorrect (alert=0x%x)\n", 2109 alert); 2110 cpuhw->flags |= PMU_F_ERR_IBE; 2111 sf_disable(); 2112 } 2113 } 2114 2115 static int cpusf_pmu_setup(unsigned int cpu, int flags) 2116 { 2117 /* Ignore the notification if no events are scheduled on the PMU. 2118 * This might be racy... 2119 */ 2120 if (!atomic_read(&num_events)) 2121 return 0; 2122 2123 local_irq_disable(); 2124 setup_pmc_cpu(&flags); 2125 local_irq_enable(); 2126 return 0; 2127 } 2128 2129 static int s390_pmu_sf_online_cpu(unsigned int cpu) 2130 { 2131 return cpusf_pmu_setup(cpu, PMC_INIT); 2132 } 2133 2134 static int s390_pmu_sf_offline_cpu(unsigned int cpu) 2135 { 2136 return cpusf_pmu_setup(cpu, PMC_RELEASE); 2137 } 2138 2139 static int param_get_sfb_size(char *buffer, const struct kernel_param *kp) 2140 { 2141 if (!cpum_sf_avail()) 2142 return -ENODEV; 2143 return sprintf(buffer, "%lu,%lu", CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB); 2144 } 2145 2146 static int param_set_sfb_size(const char *val, const struct kernel_param *kp) 2147 { 2148 int rc; 2149 unsigned long min, max; 2150 2151 if (!cpum_sf_avail()) 2152 return -ENODEV; 2153 if (!val || !strlen(val)) 2154 return -EINVAL; 2155 2156 /* Valid parameter values: "min,max" or "max" */ 2157 min = CPUM_SF_MIN_SDB; 2158 max = CPUM_SF_MAX_SDB; 2159 if (strchr(val, ',')) 2160 rc = (sscanf(val, "%lu,%lu", &min, &max) == 2) ? 0 : -EINVAL; 2161 else 2162 rc = kstrtoul(val, 10, &max); 2163 2164 if (min < 2 || min >= max || max > get_num_physpages()) 2165 rc = -EINVAL; 2166 if (rc) 2167 return rc; 2168 2169 sfb_set_limits(min, max); 2170 pr_info("The sampling buffer limits have changed to: " 2171 "min %lu max %lu (diag %lu)\n", 2172 CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB, CPUM_SF_SDB_DIAG_FACTOR); 2173 return 0; 2174 } 2175 2176 #define param_check_sfb_size(name, p) __param_check(name, p, void) 2177 static const struct kernel_param_ops param_ops_sfb_size = { 2178 .set = param_set_sfb_size, 2179 .get = param_get_sfb_size, 2180 }; 2181 2182 #define RS_INIT_FAILURE_QSI 0x0001 2183 #define RS_INIT_FAILURE_BSDES 0x0002 2184 #define RS_INIT_FAILURE_ALRT 0x0003 2185 #define RS_INIT_FAILURE_PERF 0x0004 2186 static void __init pr_cpumsf_err(unsigned int reason) 2187 { 2188 pr_err("Sampling facility support for perf is not available: " 2189 "reason %#x\n", reason); 2190 } 2191 2192 static int __init init_cpum_sampling_pmu(void) 2193 { 2194 struct hws_qsi_info_block si; 2195 int err; 2196 2197 if (!cpum_sf_avail()) 2198 return -ENODEV; 2199 2200 memset(&si, 0, sizeof(si)); 2201 if (qsi(&si)) { 2202 pr_cpumsf_err(RS_INIT_FAILURE_QSI); 2203 return -ENODEV; 2204 } 2205 2206 if (!si.as && !si.ad) 2207 return -ENODEV; 2208 2209 if (si.bsdes != sizeof(struct hws_basic_entry)) { 2210 pr_cpumsf_err(RS_INIT_FAILURE_BSDES); 2211 return -EINVAL; 2212 } 2213 2214 if (si.ad) { 2215 sfb_set_limits(CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB); 2216 /* Sampling of diagnostic data authorized, 2217 * install event into attribute list of PMU device. 2218 */ 2219 cpumsf_pmu_events_attr[SF_CYCLES_BASIC_DIAG_ATTR_IDX] = 2220 CPUMF_EVENT_PTR(SF, SF_CYCLES_BASIC_DIAG); 2221 } 2222 2223 sfdbg = debug_register(KMSG_COMPONENT, 2, 1, 80); 2224 if (!sfdbg) { 2225 pr_err("Registering for s390dbf failed\n"); 2226 return -ENOMEM; 2227 } 2228 debug_register_view(sfdbg, &debug_sprintf_view); 2229 2230 err = register_external_irq(EXT_IRQ_MEASURE_ALERT, 2231 cpumf_measurement_alert); 2232 if (err) { 2233 pr_cpumsf_err(RS_INIT_FAILURE_ALRT); 2234 debug_unregister(sfdbg); 2235 goto out; 2236 } 2237 2238 err = perf_pmu_register(&cpumf_sampling, "cpum_sf", PERF_TYPE_RAW); 2239 if (err) { 2240 pr_cpumsf_err(RS_INIT_FAILURE_PERF); 2241 unregister_external_irq(EXT_IRQ_MEASURE_ALERT, 2242 cpumf_measurement_alert); 2243 debug_unregister(sfdbg); 2244 goto out; 2245 } 2246 2247 cpuhp_setup_state(CPUHP_AP_PERF_S390_SF_ONLINE, "perf/s390/sf:online", 2248 s390_pmu_sf_online_cpu, s390_pmu_sf_offline_cpu); 2249 out: 2250 return err; 2251 } 2252 2253 arch_initcall(init_cpum_sampling_pmu); 2254 core_param(cpum_sfb_size, CPUM_SF_MAX_SDB, sfb_size, 0644); 2255