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 /* Number of perf events counting hardware events */ 518 static atomic_t num_events; 519 /* Used to avoid races in calling reserve/release_cpumf_hardware */ 520 static DEFINE_MUTEX(pmc_reserve_mutex); 521 522 #define PMC_INIT 0 523 #define PMC_RELEASE 1 524 #define PMC_FAILURE 2 525 static void setup_pmc_cpu(void *flags) 526 { 527 int err; 528 struct cpu_hw_sf *cpusf = this_cpu_ptr(&cpu_hw_sf); 529 530 err = 0; 531 switch (*((int *) flags)) { 532 case PMC_INIT: 533 memset(cpusf, 0, sizeof(*cpusf)); 534 err = qsi(&cpusf->qsi); 535 if (err) 536 break; 537 cpusf->flags |= PMU_F_RESERVED; 538 err = sf_disable(); 539 if (err) 540 pr_err("Switching off the sampling facility failed " 541 "with rc=%i\n", err); 542 debug_sprintf_event(sfdbg, 5, 543 "setup_pmc_cpu: initialized: cpuhw=%p\n", cpusf); 544 break; 545 case PMC_RELEASE: 546 cpusf->flags &= ~PMU_F_RESERVED; 547 err = sf_disable(); 548 if (err) { 549 pr_err("Switching off the sampling facility failed " 550 "with rc=%i\n", err); 551 } else 552 deallocate_buffers(cpusf); 553 debug_sprintf_event(sfdbg, 5, 554 "setup_pmc_cpu: released: cpuhw=%p\n", cpusf); 555 break; 556 } 557 if (err) 558 *((int *) flags) |= PMC_FAILURE; 559 } 560 561 static void release_pmc_hardware(void) 562 { 563 int flags = PMC_RELEASE; 564 565 irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT); 566 on_each_cpu(setup_pmc_cpu, &flags, 1); 567 } 568 569 static int reserve_pmc_hardware(void) 570 { 571 int flags = PMC_INIT; 572 573 on_each_cpu(setup_pmc_cpu, &flags, 1); 574 if (flags & PMC_FAILURE) { 575 release_pmc_hardware(); 576 return -ENODEV; 577 } 578 irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT); 579 580 return 0; 581 } 582 583 static void hw_perf_event_destroy(struct perf_event *event) 584 { 585 /* Release PMC if this is the last perf event */ 586 if (!atomic_add_unless(&num_events, -1, 1)) { 587 mutex_lock(&pmc_reserve_mutex); 588 if (atomic_dec_return(&num_events) == 0) 589 release_pmc_hardware(); 590 mutex_unlock(&pmc_reserve_mutex); 591 } 592 } 593 594 static void hw_init_period(struct hw_perf_event *hwc, u64 period) 595 { 596 hwc->sample_period = period; 597 hwc->last_period = hwc->sample_period; 598 local64_set(&hwc->period_left, hwc->sample_period); 599 } 600 601 static void hw_reset_registers(struct hw_perf_event *hwc, 602 unsigned long *sdbt_origin) 603 { 604 /* (Re)set to first sample-data-block-table */ 605 TEAR_REG(hwc) = (unsigned long) sdbt_origin; 606 } 607 608 static unsigned long hw_limit_rate(const struct hws_qsi_info_block *si, 609 unsigned long rate) 610 { 611 return clamp_t(unsigned long, rate, 612 si->min_sampl_rate, si->max_sampl_rate); 613 } 614 615 static u32 cpumsf_pid_type(struct perf_event *event, 616 u32 pid, enum pid_type type) 617 { 618 struct task_struct *tsk; 619 620 /* Idle process */ 621 if (!pid) 622 goto out; 623 624 tsk = find_task_by_pid_ns(pid, &init_pid_ns); 625 pid = -1; 626 if (tsk) { 627 /* 628 * Only top level events contain the pid namespace in which 629 * they are created. 630 */ 631 if (event->parent) 632 event = event->parent; 633 pid = __task_pid_nr_ns(tsk, type, event->ns); 634 /* 635 * See also 1d953111b648 636 * "perf/core: Don't report zero PIDs for exiting tasks". 637 */ 638 if (!pid && !pid_alive(tsk)) 639 pid = -1; 640 } 641 out: 642 return pid; 643 } 644 645 static void cpumsf_output_event_pid(struct perf_event *event, 646 struct perf_sample_data *data, 647 struct pt_regs *regs) 648 { 649 u32 pid; 650 struct perf_event_header header; 651 struct perf_output_handle handle; 652 653 /* 654 * Obtain the PID from the basic-sampling data entry and 655 * correct the data->tid_entry.pid value. 656 */ 657 pid = data->tid_entry.pid; 658 659 /* Protect callchain buffers, tasks */ 660 rcu_read_lock(); 661 662 perf_prepare_sample(&header, data, event, regs); 663 if (perf_output_begin(&handle, event, header.size)) 664 goto out; 665 666 /* Update the process ID (see also kernel/events/core.c) */ 667 data->tid_entry.pid = cpumsf_pid_type(event, pid, PIDTYPE_TGID); 668 data->tid_entry.tid = cpumsf_pid_type(event, pid, PIDTYPE_PID); 669 670 perf_output_sample(&handle, &header, data, event); 671 perf_output_end(&handle); 672 out: 673 rcu_read_unlock(); 674 } 675 676 static unsigned long getrate(bool freq, unsigned long sample, 677 struct hws_qsi_info_block *si) 678 { 679 unsigned long rate; 680 681 if (freq) { 682 rate = freq_to_sample_rate(si, sample); 683 rate = hw_limit_rate(si, rate); 684 } else { 685 /* The min/max sampling rates specifies the valid range 686 * of sample periods. If the specified sample period is 687 * out of range, limit the period to the range boundary. 688 */ 689 rate = hw_limit_rate(si, sample); 690 691 /* The perf core maintains a maximum sample rate that is 692 * configurable through the sysctl interface. Ensure the 693 * sampling rate does not exceed this value. This also helps 694 * to avoid throttling when pushing samples with 695 * perf_event_overflow(). 696 */ 697 if (sample_rate_to_freq(si, rate) > 698 sysctl_perf_event_sample_rate) { 699 debug_sprintf_event(sfdbg, 1, 700 "Sampling rate exceeds maximum " 701 "perf sample rate\n"); 702 rate = 0; 703 } 704 } 705 return rate; 706 } 707 708 /* The sampling information (si) contains information about the 709 * min/max sampling intervals and the CPU speed. So calculate the 710 * correct sampling interval and avoid the whole period adjust 711 * feedback loop. 712 * 713 * Since the CPU Measurement sampling facility can not handle frequency 714 * calculate the sampling interval when frequency is specified using 715 * this formula: 716 * interval := cpu_speed * 1000000 / sample_freq 717 * 718 * Returns errno on bad input and zero on success with parameter interval 719 * set to the correct sampling rate. 720 * 721 * Note: This function turns off freq bit to avoid calling function 722 * perf_adjust_period(). This causes frequency adjustment in the common 723 * code part which causes tremendous variations in the counter values. 724 */ 725 static int __hw_perf_event_init_rate(struct perf_event *event, 726 struct hws_qsi_info_block *si) 727 { 728 struct perf_event_attr *attr = &event->attr; 729 struct hw_perf_event *hwc = &event->hw; 730 unsigned long rate; 731 732 if (attr->freq) { 733 if (!attr->sample_freq) 734 return -EINVAL; 735 rate = getrate(attr->freq, attr->sample_freq, si); 736 attr->freq = 0; /* Don't call perf_adjust_period() */ 737 SAMPL_FLAGS(hwc) |= PERF_CPUM_SF_FREQ_MODE; 738 } else { 739 rate = getrate(attr->freq, attr->sample_period, si); 740 if (!rate) 741 return -EINVAL; 742 } 743 attr->sample_period = rate; 744 SAMPL_RATE(hwc) = rate; 745 hw_init_period(hwc, SAMPL_RATE(hwc)); 746 debug_sprintf_event(sfdbg, 4, "__hw_perf_event_init_rate:" 747 "cpu:%d period:%llx freq:%d,%#lx\n", event->cpu, 748 event->attr.sample_period, event->attr.freq, 749 SAMPLE_FREQ_MODE(hwc)); 750 return 0; 751 } 752 753 static int __hw_perf_event_init(struct perf_event *event) 754 { 755 struct cpu_hw_sf *cpuhw; 756 struct hws_qsi_info_block si; 757 struct perf_event_attr *attr = &event->attr; 758 struct hw_perf_event *hwc = &event->hw; 759 int cpu, err; 760 761 /* Reserve CPU-measurement sampling facility */ 762 err = 0; 763 if (!atomic_inc_not_zero(&num_events)) { 764 mutex_lock(&pmc_reserve_mutex); 765 if (atomic_read(&num_events) == 0 && reserve_pmc_hardware()) 766 err = -EBUSY; 767 else 768 atomic_inc(&num_events); 769 mutex_unlock(&pmc_reserve_mutex); 770 } 771 event->destroy = hw_perf_event_destroy; 772 773 if (err) 774 goto out; 775 776 /* Access per-CPU sampling information (query sampling info) */ 777 /* 778 * The event->cpu value can be -1 to count on every CPU, for example, 779 * when attaching to a task. If this is specified, use the query 780 * sampling info from the current CPU, otherwise use event->cpu to 781 * retrieve the per-CPU information. 782 * Later, cpuhw indicates whether to allocate sampling buffers for a 783 * particular CPU (cpuhw!=NULL) or each online CPU (cpuw==NULL). 784 */ 785 memset(&si, 0, sizeof(si)); 786 cpuhw = NULL; 787 if (event->cpu == -1) 788 qsi(&si); 789 else { 790 /* Event is pinned to a particular CPU, retrieve the per-CPU 791 * sampling structure for accessing the CPU-specific QSI. 792 */ 793 cpuhw = &per_cpu(cpu_hw_sf, event->cpu); 794 si = cpuhw->qsi; 795 } 796 797 /* Check sampling facility authorization and, if not authorized, 798 * fall back to other PMUs. It is safe to check any CPU because 799 * the authorization is identical for all configured CPUs. 800 */ 801 if (!si.as) { 802 err = -ENOENT; 803 goto out; 804 } 805 806 if (si.ribm & CPU_MF_SF_RIBM_NOTAV) { 807 pr_warn("CPU Measurement Facility sampling is temporarily not available\n"); 808 err = -EBUSY; 809 goto out; 810 } 811 812 /* Always enable basic sampling */ 813 SAMPL_FLAGS(hwc) = PERF_CPUM_SF_BASIC_MODE; 814 815 /* Check if diagnostic sampling is requested. Deny if the required 816 * sampling authorization is missing. 817 */ 818 if (attr->config == PERF_EVENT_CPUM_SF_DIAG) { 819 if (!si.ad) { 820 err = -EPERM; 821 goto out; 822 } 823 SAMPL_FLAGS(hwc) |= PERF_CPUM_SF_DIAG_MODE; 824 } 825 826 /* Check and set other sampling flags */ 827 if (attr->config1 & PERF_CPUM_SF_FULL_BLOCKS) 828 SAMPL_FLAGS(hwc) |= PERF_CPUM_SF_FULL_BLOCKS; 829 830 err = __hw_perf_event_init_rate(event, &si); 831 if (err) 832 goto out; 833 834 /* Initialize sample data overflow accounting */ 835 hwc->extra_reg.reg = REG_OVERFLOW; 836 OVERFLOW_REG(hwc) = 0; 837 838 /* Use AUX buffer. No need to allocate it by ourself */ 839 if (attr->config == PERF_EVENT_CPUM_SF_DIAG) 840 return 0; 841 842 /* Allocate the per-CPU sampling buffer using the CPU information 843 * from the event. If the event is not pinned to a particular 844 * CPU (event->cpu == -1; or cpuhw == NULL), allocate sampling 845 * buffers for each online CPU. 846 */ 847 if (cpuhw) 848 /* Event is pinned to a particular CPU */ 849 err = allocate_buffers(cpuhw, hwc); 850 else { 851 /* Event is not pinned, allocate sampling buffer on 852 * each online CPU 853 */ 854 for_each_online_cpu(cpu) { 855 cpuhw = &per_cpu(cpu_hw_sf, cpu); 856 err = allocate_buffers(cpuhw, hwc); 857 if (err) 858 break; 859 } 860 } 861 862 /* If PID/TID sampling is active, replace the default overflow 863 * handler to extract and resolve the PIDs from the basic-sampling 864 * data entries. 865 */ 866 if (event->attr.sample_type & PERF_SAMPLE_TID) 867 if (is_default_overflow_handler(event)) 868 event->overflow_handler = cpumsf_output_event_pid; 869 out: 870 return err; 871 } 872 873 static int cpumsf_pmu_event_init(struct perf_event *event) 874 { 875 int err; 876 877 /* No support for taken branch sampling */ 878 if (has_branch_stack(event)) 879 return -EOPNOTSUPP; 880 881 switch (event->attr.type) { 882 case PERF_TYPE_RAW: 883 if ((event->attr.config != PERF_EVENT_CPUM_SF) && 884 (event->attr.config != PERF_EVENT_CPUM_SF_DIAG)) 885 return -ENOENT; 886 break; 887 case PERF_TYPE_HARDWARE: 888 /* Support sampling of CPU cycles in addition to the 889 * counter facility. However, the counter facility 890 * is more precise and, hence, restrict this PMU to 891 * sampling events only. 892 */ 893 if (event->attr.config != PERF_COUNT_HW_CPU_CYCLES) 894 return -ENOENT; 895 if (!is_sampling_event(event)) 896 return -ENOENT; 897 break; 898 default: 899 return -ENOENT; 900 } 901 902 /* Check online status of the CPU to which the event is pinned */ 903 if (event->cpu >= 0 && !cpu_online(event->cpu)) 904 return -ENODEV; 905 906 /* Force reset of idle/hv excludes regardless of what the 907 * user requested. 908 */ 909 if (event->attr.exclude_hv) 910 event->attr.exclude_hv = 0; 911 if (event->attr.exclude_idle) 912 event->attr.exclude_idle = 0; 913 914 err = __hw_perf_event_init(event); 915 if (unlikely(err)) 916 if (event->destroy) 917 event->destroy(event); 918 return err; 919 } 920 921 static void cpumsf_pmu_enable(struct pmu *pmu) 922 { 923 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 924 struct hw_perf_event *hwc; 925 int err; 926 927 if (cpuhw->flags & PMU_F_ENABLED) 928 return; 929 930 if (cpuhw->flags & PMU_F_ERR_MASK) 931 return; 932 933 /* Check whether to extent the sampling buffer. 934 * 935 * Two conditions trigger an increase of the sampling buffer for a 936 * perf event: 937 * 1. Postponed buffer allocations from the event initialization. 938 * 2. Sampling overflows that contribute to pending allocations. 939 * 940 * Note that the extend_sampling_buffer() function disables the sampling 941 * facility, but it can be fully re-enabled using sampling controls that 942 * have been saved in cpumsf_pmu_disable(). 943 */ 944 if (cpuhw->event) { 945 hwc = &cpuhw->event->hw; 946 if (!(SAMPL_DIAG_MODE(hwc))) { 947 /* 948 * Account number of overflow-designated 949 * buffer extents 950 */ 951 sfb_account_overflows(cpuhw, hwc); 952 if (sfb_has_pending_allocs(&cpuhw->sfb, hwc)) 953 extend_sampling_buffer(&cpuhw->sfb, hwc); 954 } 955 /* Rate may be adjusted with ioctl() */ 956 cpuhw->lsctl.interval = SAMPL_RATE(&cpuhw->event->hw); 957 } 958 959 /* (Re)enable the PMU and sampling facility */ 960 cpuhw->flags |= PMU_F_ENABLED; 961 barrier(); 962 963 err = lsctl(&cpuhw->lsctl); 964 if (err) { 965 cpuhw->flags &= ~PMU_F_ENABLED; 966 pr_err("Loading sampling controls failed: op=%i err=%i\n", 967 1, err); 968 return; 969 } 970 971 /* Load current program parameter */ 972 lpp(&S390_lowcore.lpp); 973 974 debug_sprintf_event(sfdbg, 6, "pmu_enable: es=%i cs=%i ed=%i cd=%i " 975 "interval:%lx tear=%p dear=%p\n", 976 cpuhw->lsctl.es, cpuhw->lsctl.cs, cpuhw->lsctl.ed, 977 cpuhw->lsctl.cd, cpuhw->lsctl.interval, 978 (void *) cpuhw->lsctl.tear, 979 (void *) cpuhw->lsctl.dear); 980 } 981 982 static void cpumsf_pmu_disable(struct pmu *pmu) 983 { 984 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 985 struct hws_lsctl_request_block inactive; 986 struct hws_qsi_info_block si; 987 int err; 988 989 if (!(cpuhw->flags & PMU_F_ENABLED)) 990 return; 991 992 if (cpuhw->flags & PMU_F_ERR_MASK) 993 return; 994 995 /* Switch off sampling activation control */ 996 inactive = cpuhw->lsctl; 997 inactive.cs = 0; 998 inactive.cd = 0; 999 1000 err = lsctl(&inactive); 1001 if (err) { 1002 pr_err("Loading sampling controls failed: op=%i err=%i\n", 1003 2, err); 1004 return; 1005 } 1006 1007 /* Save state of TEAR and DEAR register contents */ 1008 if (!qsi(&si)) { 1009 /* TEAR/DEAR values are valid only if the sampling facility is 1010 * enabled. Note that cpumsf_pmu_disable() might be called even 1011 * for a disabled sampling facility because cpumsf_pmu_enable() 1012 * controls the enable/disable state. 1013 */ 1014 if (si.es) { 1015 cpuhw->lsctl.tear = si.tear; 1016 cpuhw->lsctl.dear = si.dear; 1017 } 1018 } else 1019 debug_sprintf_event(sfdbg, 3, "cpumsf_pmu_disable: " 1020 "qsi() failed with err=%i\n", err); 1021 1022 cpuhw->flags &= ~PMU_F_ENABLED; 1023 } 1024 1025 /* perf_exclude_event() - Filter event 1026 * @event: The perf event 1027 * @regs: pt_regs structure 1028 * @sde_regs: Sample-data-entry (sde) regs structure 1029 * 1030 * Filter perf events according to their exclude specification. 1031 * 1032 * Return non-zero if the event shall be excluded. 1033 */ 1034 static int perf_exclude_event(struct perf_event *event, struct pt_regs *regs, 1035 struct perf_sf_sde_regs *sde_regs) 1036 { 1037 if (event->attr.exclude_user && user_mode(regs)) 1038 return 1; 1039 if (event->attr.exclude_kernel && !user_mode(regs)) 1040 return 1; 1041 if (event->attr.exclude_guest && sde_regs->in_guest) 1042 return 1; 1043 if (event->attr.exclude_host && !sde_regs->in_guest) 1044 return 1; 1045 return 0; 1046 } 1047 1048 /* perf_push_sample() - Push samples to perf 1049 * @event: The perf event 1050 * @sample: Hardware sample data 1051 * 1052 * Use the hardware sample data to create perf event sample. The sample 1053 * is the pushed to the event subsystem and the function checks for 1054 * possible event overflows. If an event overflow occurs, the PMU is 1055 * stopped. 1056 * 1057 * Return non-zero if an event overflow occurred. 1058 */ 1059 static int perf_push_sample(struct perf_event *event, 1060 struct hws_basic_entry *basic) 1061 { 1062 int overflow; 1063 struct pt_regs regs; 1064 struct perf_sf_sde_regs *sde_regs; 1065 struct perf_sample_data data; 1066 1067 /* Setup perf sample */ 1068 perf_sample_data_init(&data, 0, event->hw.last_period); 1069 1070 /* Setup pt_regs to look like an CPU-measurement external interrupt 1071 * using the Program Request Alert code. The regs.int_parm_long 1072 * field which is unused contains additional sample-data-entry related 1073 * indicators. 1074 */ 1075 memset(®s, 0, sizeof(regs)); 1076 regs.int_code = 0x1407; 1077 regs.int_parm = CPU_MF_INT_SF_PRA; 1078 sde_regs = (struct perf_sf_sde_regs *) ®s.int_parm_long; 1079 1080 psw_bits(regs.psw).ia = basic->ia; 1081 psw_bits(regs.psw).dat = basic->T; 1082 psw_bits(regs.psw).wait = basic->W; 1083 psw_bits(regs.psw).pstate = basic->P; 1084 psw_bits(regs.psw).as = basic->AS; 1085 1086 /* 1087 * Use the hardware provided configuration level to decide if the 1088 * sample belongs to a guest or host. If that is not available, 1089 * fall back to the following heuristics: 1090 * A non-zero guest program parameter always indicates a guest 1091 * sample. Some early samples or samples from guests without 1092 * lpp usage would be misaccounted to the host. We use the asn 1093 * value as an addon heuristic to detect most of these guest samples. 1094 * If the value differs from 0xffff (the host value), we assume to 1095 * be a KVM guest. 1096 */ 1097 switch (basic->CL) { 1098 case 1: /* logical partition */ 1099 sde_regs->in_guest = 0; 1100 break; 1101 case 2: /* virtual machine */ 1102 sde_regs->in_guest = 1; 1103 break; 1104 default: /* old machine, use heuristics */ 1105 if (basic->gpp || basic->prim_asn != 0xffff) 1106 sde_regs->in_guest = 1; 1107 break; 1108 } 1109 1110 /* 1111 * Store the PID value from the sample-data-entry to be 1112 * processed and resolved by cpumsf_output_event_pid(). 1113 */ 1114 data.tid_entry.pid = basic->hpp & LPP_PID_MASK; 1115 1116 overflow = 0; 1117 if (perf_exclude_event(event, ®s, sde_regs)) 1118 goto out; 1119 if (perf_event_overflow(event, &data, ®s)) { 1120 overflow = 1; 1121 event->pmu->stop(event, 0); 1122 } 1123 perf_event_update_userpage(event); 1124 out: 1125 return overflow; 1126 } 1127 1128 static void perf_event_count_update(struct perf_event *event, u64 count) 1129 { 1130 local64_add(count, &event->count); 1131 } 1132 1133 static void debug_sample_entry(struct hws_basic_entry *sample, 1134 struct hws_trailer_entry *te) 1135 { 1136 debug_sprintf_event(sfdbg, 4, "hw_collect_samples: Found unknown " 1137 "sampling data entry: te->f=%i basic.def=%04x " 1138 "(%p)\n", 1139 te->f, sample->def, sample); 1140 } 1141 1142 /* hw_collect_samples() - Walk through a sample-data-block and collect samples 1143 * @event: The perf event 1144 * @sdbt: Sample-data-block table 1145 * @overflow: Event overflow counter 1146 * 1147 * Walks through a sample-data-block and collects sampling data entries that are 1148 * then pushed to the perf event subsystem. Depending on the sampling function, 1149 * there can be either basic-sampling or combined-sampling data entries. A 1150 * combined-sampling data entry consists of a basic- and a diagnostic-sampling 1151 * data entry. The sampling function is determined by the flags in the perf 1152 * event hardware structure. The function always works with a combined-sampling 1153 * data entry but ignores the the diagnostic portion if it is not available. 1154 * 1155 * Note that the implementation focuses on basic-sampling data entries and, if 1156 * such an entry is not valid, the entire combined-sampling data entry is 1157 * ignored. 1158 * 1159 * The overflow variables counts the number of samples that has been discarded 1160 * due to a perf event overflow. 1161 */ 1162 static void hw_collect_samples(struct perf_event *event, unsigned long *sdbt, 1163 unsigned long long *overflow) 1164 { 1165 struct hws_trailer_entry *te; 1166 struct hws_basic_entry *sample; 1167 1168 te = (struct hws_trailer_entry *) trailer_entry_ptr(*sdbt); 1169 sample = (struct hws_basic_entry *) *sdbt; 1170 while ((unsigned long *) sample < (unsigned long *) te) { 1171 /* Check for an empty sample */ 1172 if (!sample->def) 1173 break; 1174 1175 /* Update perf event period */ 1176 perf_event_count_update(event, SAMPL_RATE(&event->hw)); 1177 1178 /* Check whether sample is valid */ 1179 if (sample->def == 0x0001) { 1180 /* If an event overflow occurred, the PMU is stopped to 1181 * throttle event delivery. Remaining sample data is 1182 * discarded. 1183 */ 1184 if (!*overflow) { 1185 /* Check whether sample is consistent */ 1186 if (sample->I == 0 && sample->W == 0) { 1187 /* Deliver sample data to perf */ 1188 *overflow = perf_push_sample(event, 1189 sample); 1190 } 1191 } else 1192 /* Count discarded samples */ 1193 *overflow += 1; 1194 } else { 1195 debug_sample_entry(sample, te); 1196 /* Sample slot is not yet written or other record. 1197 * 1198 * This condition can occur if the buffer was reused 1199 * from a combined basic- and diagnostic-sampling. 1200 * If only basic-sampling is then active, entries are 1201 * written into the larger diagnostic entries. 1202 * This is typically the case for sample-data-blocks 1203 * that are not full. Stop processing if the first 1204 * invalid format was detected. 1205 */ 1206 if (!te->f) 1207 break; 1208 } 1209 1210 /* Reset sample slot and advance to next sample */ 1211 sample->def = 0; 1212 sample++; 1213 } 1214 } 1215 1216 /* hw_perf_event_update() - Process sampling buffer 1217 * @event: The perf event 1218 * @flush_all: Flag to also flush partially filled sample-data-blocks 1219 * 1220 * Processes the sampling buffer and create perf event samples. 1221 * The sampling buffer position are retrieved and saved in the TEAR_REG 1222 * register of the specified perf event. 1223 * 1224 * Only full sample-data-blocks are processed. Specify the flash_all flag 1225 * to also walk through partially filled sample-data-blocks. It is ignored 1226 * if PERF_CPUM_SF_FULL_BLOCKS is set. The PERF_CPUM_SF_FULL_BLOCKS flag 1227 * enforces the processing of full sample-data-blocks only (trailer entries 1228 * with the block-full-indicator bit set). 1229 */ 1230 static void hw_perf_event_update(struct perf_event *event, int flush_all) 1231 { 1232 struct hw_perf_event *hwc = &event->hw; 1233 struct hws_trailer_entry *te; 1234 unsigned long *sdbt; 1235 unsigned long long event_overflow, sampl_overflow, num_sdb, te_flags; 1236 int done; 1237 1238 /* 1239 * AUX buffer is used when in diagnostic sampling mode. 1240 * No perf events/samples are created. 1241 */ 1242 if (SAMPL_DIAG_MODE(&event->hw)) 1243 return; 1244 1245 if (flush_all && SDB_FULL_BLOCKS(hwc)) 1246 flush_all = 0; 1247 1248 sdbt = (unsigned long *) TEAR_REG(hwc); 1249 done = event_overflow = sampl_overflow = num_sdb = 0; 1250 while (!done) { 1251 /* Get the trailer entry of the sample-data-block */ 1252 te = (struct hws_trailer_entry *) trailer_entry_ptr(*sdbt); 1253 1254 /* Leave loop if no more work to do (block full indicator) */ 1255 if (!te->f) { 1256 done = 1; 1257 if (!flush_all) 1258 break; 1259 } 1260 1261 /* Check the sample overflow count */ 1262 if (te->overflow) 1263 /* Account sample overflows and, if a particular limit 1264 * is reached, extend the sampling buffer. 1265 * For details, see sfb_account_overflows(). 1266 */ 1267 sampl_overflow += te->overflow; 1268 1269 /* Timestamps are valid for full sample-data-blocks only */ 1270 debug_sprintf_event(sfdbg, 6, "hw_perf_event_update: sdbt=%p " 1271 "overflow=%llu timestamp=%#llx\n", 1272 sdbt, te->overflow, 1273 (te->f) ? trailer_timestamp(te) : 0ULL); 1274 1275 /* Collect all samples from a single sample-data-block and 1276 * flag if an (perf) event overflow happened. If so, the PMU 1277 * is stopped and remaining samples will be discarded. 1278 */ 1279 hw_collect_samples(event, sdbt, &event_overflow); 1280 num_sdb++; 1281 1282 /* Reset trailer (using compare-double-and-swap) */ 1283 do { 1284 te_flags = te->flags & ~SDB_TE_BUFFER_FULL_MASK; 1285 te_flags |= SDB_TE_ALERT_REQ_MASK; 1286 } while (!cmpxchg_double(&te->flags, &te->overflow, 1287 te->flags, te->overflow, 1288 te_flags, 0ULL)); 1289 1290 /* Advance to next sample-data-block */ 1291 sdbt++; 1292 if (is_link_entry(sdbt)) 1293 sdbt = get_next_sdbt(sdbt); 1294 1295 /* Update event hardware registers */ 1296 TEAR_REG(hwc) = (unsigned long) sdbt; 1297 1298 /* Stop processing sample-data if all samples of the current 1299 * sample-data-block were flushed even if it was not full. 1300 */ 1301 if (flush_all && done) 1302 break; 1303 1304 /* If an event overflow happened, discard samples by 1305 * processing any remaining sample-data-blocks. 1306 */ 1307 if (event_overflow) 1308 flush_all = 1; 1309 } 1310 1311 /* Account sample overflows in the event hardware structure */ 1312 if (sampl_overflow) 1313 OVERFLOW_REG(hwc) = DIV_ROUND_UP(OVERFLOW_REG(hwc) + 1314 sampl_overflow, 1 + num_sdb); 1315 if (sampl_overflow || event_overflow) 1316 debug_sprintf_event(sfdbg, 4, "hw_perf_event_update: " 1317 "overflow stats: sample=%llu event=%llu\n", 1318 sampl_overflow, event_overflow); 1319 } 1320 1321 #define AUX_SDB_INDEX(aux, i) ((i) % aux->sfb.num_sdb) 1322 #define AUX_SDB_NUM(aux, start, end) (end >= start ? end - start + 1 : 0) 1323 #define AUX_SDB_NUM_ALERT(aux) AUX_SDB_NUM(aux, aux->head, aux->alert_mark) 1324 #define AUX_SDB_NUM_EMPTY(aux) AUX_SDB_NUM(aux, aux->head, aux->empty_mark) 1325 1326 /* 1327 * Get trailer entry by index of SDB. 1328 */ 1329 static struct hws_trailer_entry *aux_sdb_trailer(struct aux_buffer *aux, 1330 unsigned long index) 1331 { 1332 unsigned long sdb; 1333 1334 index = AUX_SDB_INDEX(aux, index); 1335 sdb = aux->sdb_index[index]; 1336 return (struct hws_trailer_entry *)trailer_entry_ptr(sdb); 1337 } 1338 1339 /* 1340 * Finish sampling on the cpu. Called by cpumsf_pmu_del() with pmu 1341 * disabled. Collect the full SDBs in AUX buffer which have not reached 1342 * the point of alert indicator. And ignore the SDBs which are not 1343 * full. 1344 * 1345 * 1. Scan SDBs to see how much data is there and consume them. 1346 * 2. Remove alert indicator in the buffer. 1347 */ 1348 static void aux_output_end(struct perf_output_handle *handle) 1349 { 1350 unsigned long i, range_scan, idx; 1351 struct aux_buffer *aux; 1352 struct hws_trailer_entry *te; 1353 1354 aux = perf_get_aux(handle); 1355 if (!aux) 1356 return; 1357 1358 range_scan = AUX_SDB_NUM_ALERT(aux); 1359 for (i = 0, idx = aux->head; i < range_scan; i++, idx++) { 1360 te = aux_sdb_trailer(aux, idx); 1361 if (!(te->flags & SDB_TE_BUFFER_FULL_MASK)) 1362 break; 1363 } 1364 /* i is num of SDBs which are full */ 1365 perf_aux_output_end(handle, i << PAGE_SHIFT); 1366 1367 /* Remove alert indicators in the buffer */ 1368 te = aux_sdb_trailer(aux, aux->alert_mark); 1369 te->flags &= ~SDB_TE_ALERT_REQ_MASK; 1370 1371 debug_sprintf_event(sfdbg, 6, "aux_output_end: collect %lx SDBs\n", i); 1372 } 1373 1374 /* 1375 * Start sampling on the CPU. Called by cpumsf_pmu_add() when an event 1376 * is first added to the CPU or rescheduled again to the CPU. It is called 1377 * with pmu disabled. 1378 * 1379 * 1. Reset the trailer of SDBs to get ready for new data. 1380 * 2. Tell the hardware where to put the data by reset the SDBs buffer 1381 * head(tear/dear). 1382 */ 1383 static int aux_output_begin(struct perf_output_handle *handle, 1384 struct aux_buffer *aux, 1385 struct cpu_hw_sf *cpuhw) 1386 { 1387 unsigned long range; 1388 unsigned long i, range_scan, idx; 1389 unsigned long head, base, offset; 1390 struct hws_trailer_entry *te; 1391 1392 if (WARN_ON_ONCE(handle->head & ~PAGE_MASK)) 1393 return -EINVAL; 1394 1395 aux->head = handle->head >> PAGE_SHIFT; 1396 range = (handle->size + 1) >> PAGE_SHIFT; 1397 if (range <= 1) 1398 return -ENOMEM; 1399 1400 /* 1401 * SDBs between aux->head and aux->empty_mark are already ready 1402 * for new data. range_scan is num of SDBs not within them. 1403 */ 1404 if (range > AUX_SDB_NUM_EMPTY(aux)) { 1405 range_scan = range - AUX_SDB_NUM_EMPTY(aux); 1406 idx = aux->empty_mark + 1; 1407 for (i = 0; i < range_scan; i++, idx++) { 1408 te = aux_sdb_trailer(aux, idx); 1409 te->flags = te->flags & ~SDB_TE_BUFFER_FULL_MASK; 1410 te->flags = te->flags & ~SDB_TE_ALERT_REQ_MASK; 1411 te->overflow = 0; 1412 } 1413 /* Save the position of empty SDBs */ 1414 aux->empty_mark = aux->head + range - 1; 1415 } 1416 1417 /* Set alert indicator */ 1418 aux->alert_mark = aux->head + range/2 - 1; 1419 te = aux_sdb_trailer(aux, aux->alert_mark); 1420 te->flags = te->flags | SDB_TE_ALERT_REQ_MASK; 1421 1422 /* Reset hardware buffer head */ 1423 head = AUX_SDB_INDEX(aux, aux->head); 1424 base = aux->sdbt_index[head / CPUM_SF_SDB_PER_TABLE]; 1425 offset = head % CPUM_SF_SDB_PER_TABLE; 1426 cpuhw->lsctl.tear = base + offset * sizeof(unsigned long); 1427 cpuhw->lsctl.dear = aux->sdb_index[head]; 1428 1429 debug_sprintf_event(sfdbg, 6, "aux_output_begin: " 1430 "head->alert_mark->empty_mark (num_alert, range)" 1431 "[%lx -> %lx -> %lx] (%lx, %lx) " 1432 "tear index %lx, tear %lx dear %lx\n", 1433 aux->head, aux->alert_mark, aux->empty_mark, 1434 AUX_SDB_NUM_ALERT(aux), range, 1435 head / CPUM_SF_SDB_PER_TABLE, 1436 cpuhw->lsctl.tear, 1437 cpuhw->lsctl.dear); 1438 1439 return 0; 1440 } 1441 1442 /* 1443 * Set alert indicator on SDB at index @alert_index while sampler is running. 1444 * 1445 * Return true if successfully. 1446 * Return false if full indicator is already set by hardware sampler. 1447 */ 1448 static bool aux_set_alert(struct aux_buffer *aux, unsigned long alert_index, 1449 unsigned long long *overflow) 1450 { 1451 unsigned long long orig_overflow, orig_flags, new_flags; 1452 struct hws_trailer_entry *te; 1453 1454 te = aux_sdb_trailer(aux, alert_index); 1455 do { 1456 orig_flags = te->flags; 1457 orig_overflow = te->overflow; 1458 *overflow = orig_overflow; 1459 if (orig_flags & SDB_TE_BUFFER_FULL_MASK) { 1460 /* 1461 * SDB is already set by hardware. 1462 * Abort and try to set somewhere 1463 * behind. 1464 */ 1465 return false; 1466 } 1467 new_flags = orig_flags | SDB_TE_ALERT_REQ_MASK; 1468 } while (!cmpxchg_double(&te->flags, &te->overflow, 1469 orig_flags, orig_overflow, 1470 new_flags, 0ULL)); 1471 return true; 1472 } 1473 1474 /* 1475 * aux_reset_buffer() - Scan and setup SDBs for new samples 1476 * @aux: The AUX buffer to set 1477 * @range: The range of SDBs to scan started from aux->head 1478 * @overflow: Set to overflow count 1479 * 1480 * Set alert indicator on the SDB at index of aux->alert_mark. If this SDB is 1481 * marked as empty, check if it is already set full by the hardware sampler. 1482 * If yes, that means new data is already there before we can set an alert 1483 * indicator. Caller should try to set alert indicator to some position behind. 1484 * 1485 * Scan the SDBs in AUX buffer from behind aux->empty_mark. They are used 1486 * previously and have already been consumed by user space. Reset these SDBs 1487 * (clear full indicator and alert indicator) for new data. 1488 * If aux->alert_mark fall in this area, just set it. Overflow count is 1489 * recorded while scanning. 1490 * 1491 * SDBs between aux->head and aux->empty_mark are already reset at last time. 1492 * and ready for new samples. So scanning on this area could be skipped. 1493 * 1494 * Return true if alert indicator is set successfully and false if not. 1495 */ 1496 static bool aux_reset_buffer(struct aux_buffer *aux, unsigned long range, 1497 unsigned long long *overflow) 1498 { 1499 unsigned long long orig_overflow, orig_flags, new_flags; 1500 unsigned long i, range_scan, idx; 1501 struct hws_trailer_entry *te; 1502 1503 if (range <= AUX_SDB_NUM_EMPTY(aux)) 1504 /* 1505 * No need to scan. All SDBs in range are marked as empty. 1506 * Just set alert indicator. Should check race with hardware 1507 * sampler. 1508 */ 1509 return aux_set_alert(aux, aux->alert_mark, overflow); 1510 1511 if (aux->alert_mark <= aux->empty_mark) 1512 /* 1513 * Set alert indicator on empty SDB. Should check race 1514 * with hardware sampler. 1515 */ 1516 if (!aux_set_alert(aux, aux->alert_mark, overflow)) 1517 return false; 1518 1519 /* 1520 * Scan the SDBs to clear full and alert indicator used previously. 1521 * Start scanning from one SDB behind empty_mark. If the new alert 1522 * indicator fall into this range, set it. 1523 */ 1524 range_scan = range - AUX_SDB_NUM_EMPTY(aux); 1525 idx = aux->empty_mark + 1; 1526 for (i = 0; i < range_scan; i++, idx++) { 1527 te = aux_sdb_trailer(aux, idx); 1528 do { 1529 orig_flags = te->flags; 1530 orig_overflow = te->overflow; 1531 new_flags = orig_flags & ~SDB_TE_BUFFER_FULL_MASK; 1532 if (idx == aux->alert_mark) 1533 new_flags |= SDB_TE_ALERT_REQ_MASK; 1534 else 1535 new_flags &= ~SDB_TE_ALERT_REQ_MASK; 1536 } while (!cmpxchg_double(&te->flags, &te->overflow, 1537 orig_flags, orig_overflow, 1538 new_flags, 0ULL)); 1539 *overflow += orig_overflow; 1540 } 1541 1542 /* Update empty_mark to new position */ 1543 aux->empty_mark = aux->head + range - 1; 1544 1545 return true; 1546 } 1547 1548 /* 1549 * Measurement alert handler for diagnostic mode sampling. 1550 */ 1551 static void hw_collect_aux(struct cpu_hw_sf *cpuhw) 1552 { 1553 struct aux_buffer *aux; 1554 int done = 0; 1555 unsigned long range = 0, size; 1556 unsigned long long overflow = 0; 1557 struct perf_output_handle *handle = &cpuhw->handle; 1558 unsigned long num_sdb; 1559 1560 aux = perf_get_aux(handle); 1561 if (WARN_ON_ONCE(!aux)) 1562 return; 1563 1564 /* Inform user space new data arrived */ 1565 size = AUX_SDB_NUM_ALERT(aux) << PAGE_SHIFT; 1566 perf_aux_output_end(handle, size); 1567 num_sdb = aux->sfb.num_sdb; 1568 1569 while (!done) { 1570 /* Get an output handle */ 1571 aux = perf_aux_output_begin(handle, cpuhw->event); 1572 if (handle->size == 0) { 1573 pr_err("The AUX buffer with %lu pages for the " 1574 "diagnostic-sampling mode is full\n", 1575 num_sdb); 1576 debug_sprintf_event(sfdbg, 1, "AUX buffer used up\n"); 1577 break; 1578 } 1579 if (WARN_ON_ONCE(!aux)) 1580 return; 1581 1582 /* Update head and alert_mark to new position */ 1583 aux->head = handle->head >> PAGE_SHIFT; 1584 range = (handle->size + 1) >> PAGE_SHIFT; 1585 if (range == 1) 1586 aux->alert_mark = aux->head; 1587 else 1588 aux->alert_mark = aux->head + range/2 - 1; 1589 1590 if (aux_reset_buffer(aux, range, &overflow)) { 1591 if (!overflow) { 1592 done = 1; 1593 break; 1594 } 1595 size = range << PAGE_SHIFT; 1596 perf_aux_output_end(&cpuhw->handle, size); 1597 pr_err("Sample data caused the AUX buffer with %lu " 1598 "pages to overflow\n", num_sdb); 1599 debug_sprintf_event(sfdbg, 1, "head %lx range %lx " 1600 "overflow %llx\n", 1601 aux->head, range, overflow); 1602 } else { 1603 size = AUX_SDB_NUM_ALERT(aux) << PAGE_SHIFT; 1604 perf_aux_output_end(&cpuhw->handle, size); 1605 debug_sprintf_event(sfdbg, 6, "head %lx alert %lx " 1606 "already full, try another\n", 1607 aux->head, aux->alert_mark); 1608 } 1609 } 1610 1611 if (done) 1612 debug_sprintf_event(sfdbg, 6, "aux_reset_buffer: " 1613 "[%lx -> %lx -> %lx] (%lx, %lx)\n", 1614 aux->head, aux->alert_mark, aux->empty_mark, 1615 AUX_SDB_NUM_ALERT(aux), range); 1616 } 1617 1618 /* 1619 * Callback when freeing AUX buffers. 1620 */ 1621 static void aux_buffer_free(void *data) 1622 { 1623 struct aux_buffer *aux = data; 1624 unsigned long i, num_sdbt; 1625 1626 if (!aux) 1627 return; 1628 1629 /* Free SDBT. SDB is freed by the caller */ 1630 num_sdbt = aux->sfb.num_sdbt; 1631 for (i = 0; i < num_sdbt; i++) 1632 free_page(aux->sdbt_index[i]); 1633 1634 kfree(aux->sdbt_index); 1635 kfree(aux->sdb_index); 1636 kfree(aux); 1637 1638 debug_sprintf_event(sfdbg, 4, "aux_buffer_free: free " 1639 "%lu SDBTs\n", num_sdbt); 1640 } 1641 1642 static void aux_sdb_init(unsigned long sdb) 1643 { 1644 struct hws_trailer_entry *te; 1645 1646 te = (struct hws_trailer_entry *)trailer_entry_ptr(sdb); 1647 1648 /* Save clock base */ 1649 te->clock_base = 1; 1650 memcpy(&te->progusage2, &tod_clock_base[1], 8); 1651 } 1652 1653 /* 1654 * aux_buffer_setup() - Setup AUX buffer for diagnostic mode sampling 1655 * @event: Event the buffer is setup for, event->cpu == -1 means current 1656 * @pages: Array of pointers to buffer pages passed from perf core 1657 * @nr_pages: Total pages 1658 * @snapshot: Flag for snapshot mode 1659 * 1660 * This is the callback when setup an event using AUX buffer. Perf tool can 1661 * trigger this by an additional mmap() call on the event. Unlike the buffer 1662 * for basic samples, AUX buffer belongs to the event. It is scheduled with 1663 * the task among online cpus when it is a per-thread event. 1664 * 1665 * Return the private AUX buffer structure if success or NULL if fails. 1666 */ 1667 static void *aux_buffer_setup(struct perf_event *event, void **pages, 1668 int nr_pages, bool snapshot) 1669 { 1670 struct sf_buffer *sfb; 1671 struct aux_buffer *aux; 1672 unsigned long *new, *tail; 1673 int i, n_sdbt; 1674 1675 if (!nr_pages || !pages) 1676 return NULL; 1677 1678 if (nr_pages > CPUM_SF_MAX_SDB * CPUM_SF_SDB_DIAG_FACTOR) { 1679 pr_err("AUX buffer size (%i pages) is larger than the " 1680 "maximum sampling buffer limit\n", 1681 nr_pages); 1682 return NULL; 1683 } else if (nr_pages < CPUM_SF_MIN_SDB * CPUM_SF_SDB_DIAG_FACTOR) { 1684 pr_err("AUX buffer size (%i pages) is less than the " 1685 "minimum sampling buffer limit\n", 1686 nr_pages); 1687 return NULL; 1688 } 1689 1690 /* Allocate aux_buffer struct for the event */ 1691 aux = kmalloc(sizeof(struct aux_buffer), GFP_KERNEL); 1692 if (!aux) 1693 goto no_aux; 1694 sfb = &aux->sfb; 1695 1696 /* Allocate sdbt_index for fast reference */ 1697 n_sdbt = (nr_pages + CPUM_SF_SDB_PER_TABLE - 1) / CPUM_SF_SDB_PER_TABLE; 1698 aux->sdbt_index = kmalloc_array(n_sdbt, sizeof(void *), GFP_KERNEL); 1699 if (!aux->sdbt_index) 1700 goto no_sdbt_index; 1701 1702 /* Allocate sdb_index for fast reference */ 1703 aux->sdb_index = kmalloc_array(nr_pages, sizeof(void *), GFP_KERNEL); 1704 if (!aux->sdb_index) 1705 goto no_sdb_index; 1706 1707 /* Allocate the first SDBT */ 1708 sfb->num_sdbt = 0; 1709 sfb->sdbt = (unsigned long *) get_zeroed_page(GFP_KERNEL); 1710 if (!sfb->sdbt) 1711 goto no_sdbt; 1712 aux->sdbt_index[sfb->num_sdbt++] = (unsigned long)sfb->sdbt; 1713 tail = sfb->tail = sfb->sdbt; 1714 1715 /* 1716 * Link the provided pages of AUX buffer to SDBT. 1717 * Allocate SDBT if needed. 1718 */ 1719 for (i = 0; i < nr_pages; i++, tail++) { 1720 if (require_table_link(tail)) { 1721 new = (unsigned long *) get_zeroed_page(GFP_KERNEL); 1722 if (!new) 1723 goto no_sdbt; 1724 aux->sdbt_index[sfb->num_sdbt++] = (unsigned long)new; 1725 /* Link current page to tail of chain */ 1726 *tail = (unsigned long)(void *) new + 1; 1727 tail = new; 1728 } 1729 /* Tail is the entry in a SDBT */ 1730 *tail = (unsigned long)pages[i]; 1731 aux->sdb_index[i] = (unsigned long)pages[i]; 1732 aux_sdb_init((unsigned long)pages[i]); 1733 } 1734 sfb->num_sdb = nr_pages; 1735 1736 /* Link the last entry in the SDBT to the first SDBT */ 1737 *tail = (unsigned long) sfb->sdbt + 1; 1738 sfb->tail = tail; 1739 1740 /* 1741 * Initial all SDBs are zeroed. Mark it as empty. 1742 * So there is no need to clear the full indicator 1743 * when this event is first added. 1744 */ 1745 aux->empty_mark = sfb->num_sdb - 1; 1746 1747 debug_sprintf_event(sfdbg, 4, "aux_buffer_setup: setup %lu SDBTs" 1748 " and %lu SDBs\n", 1749 sfb->num_sdbt, sfb->num_sdb); 1750 1751 return aux; 1752 1753 no_sdbt: 1754 /* SDBs (AUX buffer pages) are freed by caller */ 1755 for (i = 0; i < sfb->num_sdbt; i++) 1756 free_page(aux->sdbt_index[i]); 1757 kfree(aux->sdb_index); 1758 no_sdb_index: 1759 kfree(aux->sdbt_index); 1760 no_sdbt_index: 1761 kfree(aux); 1762 no_aux: 1763 return NULL; 1764 } 1765 1766 static void cpumsf_pmu_read(struct perf_event *event) 1767 { 1768 /* Nothing to do ... updates are interrupt-driven */ 1769 } 1770 1771 /* Check if the new sampling period/freqeuncy is appropriate. 1772 * 1773 * Return non-zero on error and zero on passed checks. 1774 */ 1775 static int cpumsf_pmu_check_period(struct perf_event *event, u64 value) 1776 { 1777 struct hws_qsi_info_block si; 1778 unsigned long rate; 1779 bool do_freq; 1780 1781 memset(&si, 0, sizeof(si)); 1782 if (event->cpu == -1) { 1783 if (qsi(&si)) 1784 return -ENODEV; 1785 } else { 1786 /* Event is pinned to a particular CPU, retrieve the per-CPU 1787 * sampling structure for accessing the CPU-specific QSI. 1788 */ 1789 struct cpu_hw_sf *cpuhw = &per_cpu(cpu_hw_sf, event->cpu); 1790 1791 si = cpuhw->qsi; 1792 } 1793 1794 do_freq = !!SAMPLE_FREQ_MODE(&event->hw); 1795 rate = getrate(do_freq, value, &si); 1796 if (!rate) 1797 return -EINVAL; 1798 1799 event->attr.sample_period = rate; 1800 SAMPL_RATE(&event->hw) = rate; 1801 hw_init_period(&event->hw, SAMPL_RATE(&event->hw)); 1802 debug_sprintf_event(sfdbg, 4, "cpumsf_pmu_check_period:" 1803 "cpu:%d value:%llx period:%llx freq:%d\n", 1804 event->cpu, value, 1805 event->attr.sample_period, do_freq); 1806 return 0; 1807 } 1808 1809 /* Activate sampling control. 1810 * Next call of pmu_enable() starts sampling. 1811 */ 1812 static void cpumsf_pmu_start(struct perf_event *event, int flags) 1813 { 1814 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 1815 1816 if (WARN_ON_ONCE(!(event->hw.state & PERF_HES_STOPPED))) 1817 return; 1818 1819 if (flags & PERF_EF_RELOAD) 1820 WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE)); 1821 1822 perf_pmu_disable(event->pmu); 1823 event->hw.state = 0; 1824 cpuhw->lsctl.cs = 1; 1825 if (SAMPL_DIAG_MODE(&event->hw)) 1826 cpuhw->lsctl.cd = 1; 1827 perf_pmu_enable(event->pmu); 1828 } 1829 1830 /* Deactivate sampling control. 1831 * Next call of pmu_enable() stops sampling. 1832 */ 1833 static void cpumsf_pmu_stop(struct perf_event *event, int flags) 1834 { 1835 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 1836 1837 if (event->hw.state & PERF_HES_STOPPED) 1838 return; 1839 1840 perf_pmu_disable(event->pmu); 1841 cpuhw->lsctl.cs = 0; 1842 cpuhw->lsctl.cd = 0; 1843 event->hw.state |= PERF_HES_STOPPED; 1844 1845 if ((flags & PERF_EF_UPDATE) && !(event->hw.state & PERF_HES_UPTODATE)) { 1846 hw_perf_event_update(event, 1); 1847 event->hw.state |= PERF_HES_UPTODATE; 1848 } 1849 perf_pmu_enable(event->pmu); 1850 } 1851 1852 static int cpumsf_pmu_add(struct perf_event *event, int flags) 1853 { 1854 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 1855 struct aux_buffer *aux; 1856 int err; 1857 1858 if (cpuhw->flags & PMU_F_IN_USE) 1859 return -EAGAIN; 1860 1861 if (!SAMPL_DIAG_MODE(&event->hw) && !cpuhw->sfb.sdbt) 1862 return -EINVAL; 1863 1864 err = 0; 1865 perf_pmu_disable(event->pmu); 1866 1867 event->hw.state = PERF_HES_UPTODATE | PERF_HES_STOPPED; 1868 1869 /* Set up sampling controls. Always program the sampling register 1870 * using the SDB-table start. Reset TEAR_REG event hardware register 1871 * that is used by hw_perf_event_update() to store the sampling buffer 1872 * position after samples have been flushed. 1873 */ 1874 cpuhw->lsctl.s = 0; 1875 cpuhw->lsctl.h = 1; 1876 cpuhw->lsctl.interval = SAMPL_RATE(&event->hw); 1877 if (!SAMPL_DIAG_MODE(&event->hw)) { 1878 cpuhw->lsctl.tear = (unsigned long) cpuhw->sfb.sdbt; 1879 cpuhw->lsctl.dear = *(unsigned long *) cpuhw->sfb.sdbt; 1880 hw_reset_registers(&event->hw, cpuhw->sfb.sdbt); 1881 } 1882 1883 /* Ensure sampling functions are in the disabled state. If disabled, 1884 * switch on sampling enable control. */ 1885 if (WARN_ON_ONCE(cpuhw->lsctl.es == 1 || cpuhw->lsctl.ed == 1)) { 1886 err = -EAGAIN; 1887 goto out; 1888 } 1889 if (SAMPL_DIAG_MODE(&event->hw)) { 1890 aux = perf_aux_output_begin(&cpuhw->handle, event); 1891 if (!aux) { 1892 err = -EINVAL; 1893 goto out; 1894 } 1895 err = aux_output_begin(&cpuhw->handle, aux, cpuhw); 1896 if (err) 1897 goto out; 1898 cpuhw->lsctl.ed = 1; 1899 } 1900 cpuhw->lsctl.es = 1; 1901 1902 /* Set in_use flag and store event */ 1903 cpuhw->event = event; 1904 cpuhw->flags |= PMU_F_IN_USE; 1905 1906 if (flags & PERF_EF_START) 1907 cpumsf_pmu_start(event, PERF_EF_RELOAD); 1908 out: 1909 perf_event_update_userpage(event); 1910 perf_pmu_enable(event->pmu); 1911 return err; 1912 } 1913 1914 static void cpumsf_pmu_del(struct perf_event *event, int flags) 1915 { 1916 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 1917 1918 perf_pmu_disable(event->pmu); 1919 cpumsf_pmu_stop(event, PERF_EF_UPDATE); 1920 1921 cpuhw->lsctl.es = 0; 1922 cpuhw->lsctl.ed = 0; 1923 cpuhw->flags &= ~PMU_F_IN_USE; 1924 cpuhw->event = NULL; 1925 1926 if (SAMPL_DIAG_MODE(&event->hw)) 1927 aux_output_end(&cpuhw->handle); 1928 perf_event_update_userpage(event); 1929 perf_pmu_enable(event->pmu); 1930 } 1931 1932 CPUMF_EVENT_ATTR(SF, SF_CYCLES_BASIC, PERF_EVENT_CPUM_SF); 1933 CPUMF_EVENT_ATTR(SF, SF_CYCLES_BASIC_DIAG, PERF_EVENT_CPUM_SF_DIAG); 1934 1935 /* Attribute list for CPU_SF. 1936 * 1937 * The availablitiy depends on the CPU_MF sampling facility authorization 1938 * for basic + diagnositic samples. This is determined at initialization 1939 * time by the sampling facility device driver. 1940 * If the authorization for basic samples is turned off, it should be 1941 * also turned off for diagnostic sampling. 1942 * 1943 * During initialization of the device driver, check the authorization 1944 * level for diagnostic sampling and installs the attribute 1945 * file for diagnostic sampling if necessary. 1946 * 1947 * For now install a placeholder to reference all possible attributes: 1948 * SF_CYCLES_BASIC and SF_CYCLES_BASIC_DIAG. 1949 * Add another entry for the final NULL pointer. 1950 */ 1951 enum { 1952 SF_CYCLES_BASIC_ATTR_IDX = 0, 1953 SF_CYCLES_BASIC_DIAG_ATTR_IDX, 1954 SF_CYCLES_ATTR_MAX 1955 }; 1956 1957 static struct attribute *cpumsf_pmu_events_attr[SF_CYCLES_ATTR_MAX + 1] = { 1958 [SF_CYCLES_BASIC_ATTR_IDX] = CPUMF_EVENT_PTR(SF, SF_CYCLES_BASIC) 1959 }; 1960 1961 PMU_FORMAT_ATTR(event, "config:0-63"); 1962 1963 static struct attribute *cpumsf_pmu_format_attr[] = { 1964 &format_attr_event.attr, 1965 NULL, 1966 }; 1967 1968 static struct attribute_group cpumsf_pmu_events_group = { 1969 .name = "events", 1970 .attrs = cpumsf_pmu_events_attr, 1971 }; 1972 1973 static struct attribute_group cpumsf_pmu_format_group = { 1974 .name = "format", 1975 .attrs = cpumsf_pmu_format_attr, 1976 }; 1977 1978 static const struct attribute_group *cpumsf_pmu_attr_groups[] = { 1979 &cpumsf_pmu_events_group, 1980 &cpumsf_pmu_format_group, 1981 NULL, 1982 }; 1983 1984 static struct pmu cpumf_sampling = { 1985 .pmu_enable = cpumsf_pmu_enable, 1986 .pmu_disable = cpumsf_pmu_disable, 1987 1988 .event_init = cpumsf_pmu_event_init, 1989 .add = cpumsf_pmu_add, 1990 .del = cpumsf_pmu_del, 1991 1992 .start = cpumsf_pmu_start, 1993 .stop = cpumsf_pmu_stop, 1994 .read = cpumsf_pmu_read, 1995 1996 .attr_groups = cpumsf_pmu_attr_groups, 1997 1998 .setup_aux = aux_buffer_setup, 1999 .free_aux = aux_buffer_free, 2000 2001 .check_period = cpumsf_pmu_check_period, 2002 }; 2003 2004 static void cpumf_measurement_alert(struct ext_code ext_code, 2005 unsigned int alert, unsigned long unused) 2006 { 2007 struct cpu_hw_sf *cpuhw; 2008 2009 if (!(alert & CPU_MF_INT_SF_MASK)) 2010 return; 2011 inc_irq_stat(IRQEXT_CMS); 2012 cpuhw = this_cpu_ptr(&cpu_hw_sf); 2013 2014 /* Measurement alerts are shared and might happen when the PMU 2015 * is not reserved. Ignore these alerts in this case. */ 2016 if (!(cpuhw->flags & PMU_F_RESERVED)) 2017 return; 2018 2019 /* The processing below must take care of multiple alert events that 2020 * might be indicated concurrently. */ 2021 2022 /* Program alert request */ 2023 if (alert & CPU_MF_INT_SF_PRA) { 2024 if (cpuhw->flags & PMU_F_IN_USE) 2025 if (SAMPL_DIAG_MODE(&cpuhw->event->hw)) 2026 hw_collect_aux(cpuhw); 2027 else 2028 hw_perf_event_update(cpuhw->event, 0); 2029 else 2030 WARN_ON_ONCE(!(cpuhw->flags & PMU_F_IN_USE)); 2031 } 2032 2033 /* Report measurement alerts only for non-PRA codes */ 2034 if (alert != CPU_MF_INT_SF_PRA) 2035 debug_sprintf_event(sfdbg, 6, "measurement alert: %#x\n", 2036 alert); 2037 2038 /* Sampling authorization change request */ 2039 if (alert & CPU_MF_INT_SF_SACA) 2040 qsi(&cpuhw->qsi); 2041 2042 /* Loss of sample data due to high-priority machine activities */ 2043 if (alert & CPU_MF_INT_SF_LSDA) { 2044 pr_err("Sample data was lost\n"); 2045 cpuhw->flags |= PMU_F_ERR_LSDA; 2046 sf_disable(); 2047 } 2048 2049 /* Invalid sampling buffer entry */ 2050 if (alert & (CPU_MF_INT_SF_IAE|CPU_MF_INT_SF_ISE)) { 2051 pr_err("A sampling buffer entry is incorrect (alert=0x%x)\n", 2052 alert); 2053 cpuhw->flags |= PMU_F_ERR_IBE; 2054 sf_disable(); 2055 } 2056 } 2057 2058 static int cpusf_pmu_setup(unsigned int cpu, int flags) 2059 { 2060 /* Ignore the notification if no events are scheduled on the PMU. 2061 * This might be racy... 2062 */ 2063 if (!atomic_read(&num_events)) 2064 return 0; 2065 2066 local_irq_disable(); 2067 setup_pmc_cpu(&flags); 2068 local_irq_enable(); 2069 return 0; 2070 } 2071 2072 static int s390_pmu_sf_online_cpu(unsigned int cpu) 2073 { 2074 return cpusf_pmu_setup(cpu, PMC_INIT); 2075 } 2076 2077 static int s390_pmu_sf_offline_cpu(unsigned int cpu) 2078 { 2079 return cpusf_pmu_setup(cpu, PMC_RELEASE); 2080 } 2081 2082 static int param_get_sfb_size(char *buffer, const struct kernel_param *kp) 2083 { 2084 if (!cpum_sf_avail()) 2085 return -ENODEV; 2086 return sprintf(buffer, "%lu,%lu", CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB); 2087 } 2088 2089 static int param_set_sfb_size(const char *val, const struct kernel_param *kp) 2090 { 2091 int rc; 2092 unsigned long min, max; 2093 2094 if (!cpum_sf_avail()) 2095 return -ENODEV; 2096 if (!val || !strlen(val)) 2097 return -EINVAL; 2098 2099 /* Valid parameter values: "min,max" or "max" */ 2100 min = CPUM_SF_MIN_SDB; 2101 max = CPUM_SF_MAX_SDB; 2102 if (strchr(val, ',')) 2103 rc = (sscanf(val, "%lu,%lu", &min, &max) == 2) ? 0 : -EINVAL; 2104 else 2105 rc = kstrtoul(val, 10, &max); 2106 2107 if (min < 2 || min >= max || max > get_num_physpages()) 2108 rc = -EINVAL; 2109 if (rc) 2110 return rc; 2111 2112 sfb_set_limits(min, max); 2113 pr_info("The sampling buffer limits have changed to: " 2114 "min=%lu max=%lu (diag=x%lu)\n", 2115 CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB, CPUM_SF_SDB_DIAG_FACTOR); 2116 return 0; 2117 } 2118 2119 #define param_check_sfb_size(name, p) __param_check(name, p, void) 2120 static const struct kernel_param_ops param_ops_sfb_size = { 2121 .set = param_set_sfb_size, 2122 .get = param_get_sfb_size, 2123 }; 2124 2125 #define RS_INIT_FAILURE_QSI 0x0001 2126 #define RS_INIT_FAILURE_BSDES 0x0002 2127 #define RS_INIT_FAILURE_ALRT 0x0003 2128 #define RS_INIT_FAILURE_PERF 0x0004 2129 static void __init pr_cpumsf_err(unsigned int reason) 2130 { 2131 pr_err("Sampling facility support for perf is not available: " 2132 "reason=%04x\n", reason); 2133 } 2134 2135 static int __init init_cpum_sampling_pmu(void) 2136 { 2137 struct hws_qsi_info_block si; 2138 int err; 2139 2140 if (!cpum_sf_avail()) 2141 return -ENODEV; 2142 2143 memset(&si, 0, sizeof(si)); 2144 if (qsi(&si)) { 2145 pr_cpumsf_err(RS_INIT_FAILURE_QSI); 2146 return -ENODEV; 2147 } 2148 2149 if (!si.as && !si.ad) 2150 return -ENODEV; 2151 2152 if (si.bsdes != sizeof(struct hws_basic_entry)) { 2153 pr_cpumsf_err(RS_INIT_FAILURE_BSDES); 2154 return -EINVAL; 2155 } 2156 2157 if (si.ad) { 2158 sfb_set_limits(CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB); 2159 /* Sampling of diagnostic data authorized, 2160 * install event into attribute list of PMU device. 2161 */ 2162 cpumsf_pmu_events_attr[SF_CYCLES_BASIC_DIAG_ATTR_IDX] = 2163 CPUMF_EVENT_PTR(SF, SF_CYCLES_BASIC_DIAG); 2164 } 2165 2166 sfdbg = debug_register(KMSG_COMPONENT, 2, 1, 80); 2167 if (!sfdbg) { 2168 pr_err("Registering for s390dbf failed\n"); 2169 return -ENOMEM; 2170 } 2171 debug_register_view(sfdbg, &debug_sprintf_view); 2172 2173 err = register_external_irq(EXT_IRQ_MEASURE_ALERT, 2174 cpumf_measurement_alert); 2175 if (err) { 2176 pr_cpumsf_err(RS_INIT_FAILURE_ALRT); 2177 debug_unregister(sfdbg); 2178 goto out; 2179 } 2180 2181 err = perf_pmu_register(&cpumf_sampling, "cpum_sf", PERF_TYPE_RAW); 2182 if (err) { 2183 pr_cpumsf_err(RS_INIT_FAILURE_PERF); 2184 unregister_external_irq(EXT_IRQ_MEASURE_ALERT, 2185 cpumf_measurement_alert); 2186 debug_unregister(sfdbg); 2187 goto out; 2188 } 2189 2190 cpuhp_setup_state(CPUHP_AP_PERF_S390_SF_ONLINE, "perf/s390/sf:online", 2191 s390_pmu_sf_online_cpu, s390_pmu_sf_offline_cpu); 2192 out: 2193 return err; 2194 } 2195 2196 arch_initcall(init_cpum_sampling_pmu); 2197 core_param(cpum_sfb_size, CPUM_SF_MAX_SDB, sfb_size, 0640); 2198