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 #include <asm-generic/io.h> 26 27 /* Minimum number of sample-data-block-tables: 28 * At least one table is required for the sampling buffer structure. 29 * A single table contains up to 511 pointers to sample-data-blocks. 30 */ 31 #define CPUM_SF_MIN_SDBT 1 32 33 /* Number of sample-data-blocks per sample-data-block-table (SDBT): 34 * A table contains SDB pointers (8 bytes) and one table-link entry 35 * that points to the origin of the next SDBT. 36 */ 37 #define CPUM_SF_SDB_PER_TABLE ((PAGE_SIZE - 8) / 8) 38 39 /* Maximum page offset for an SDBT table-link entry: 40 * If this page offset is reached, a table-link entry to the next SDBT 41 * must be added. 42 */ 43 #define CPUM_SF_SDBT_TL_OFFSET (CPUM_SF_SDB_PER_TABLE * 8) 44 static inline int require_table_link(const void *sdbt) 45 { 46 return ((unsigned long) sdbt & ~PAGE_MASK) == CPUM_SF_SDBT_TL_OFFSET; 47 } 48 49 /* Minimum and maximum sampling buffer sizes: 50 * 51 * This number represents the maximum size of the sampling buffer taking 52 * the number of sample-data-block-tables into account. Note that these 53 * numbers apply to the basic-sampling function only. 54 * The maximum number of SDBs is increased by CPUM_SF_SDB_DIAG_FACTOR if 55 * the diagnostic-sampling function is active. 56 * 57 * Sampling buffer size Buffer characteristics 58 * --------------------------------------------------- 59 * 64KB == 16 pages (4KB per page) 60 * 1 page for SDB-tables 61 * 15 pages for SDBs 62 * 63 * 32MB == 8192 pages (4KB per page) 64 * 16 pages for SDB-tables 65 * 8176 pages for SDBs 66 */ 67 static unsigned long __read_mostly CPUM_SF_MIN_SDB = 15; 68 static unsigned long __read_mostly CPUM_SF_MAX_SDB = 8176; 69 static unsigned long __read_mostly CPUM_SF_SDB_DIAG_FACTOR = 1; 70 71 struct sf_buffer { 72 unsigned long *sdbt; /* Sample-data-block-table origin */ 73 /* buffer characteristics (required for buffer increments) */ 74 unsigned long num_sdb; /* Number of sample-data-blocks */ 75 unsigned long num_sdbt; /* Number of sample-data-block-tables */ 76 unsigned long *tail; /* last sample-data-block-table */ 77 }; 78 79 struct aux_buffer { 80 struct sf_buffer sfb; 81 unsigned long head; /* index of SDB of buffer head */ 82 unsigned long alert_mark; /* index of SDB of alert request position */ 83 unsigned long empty_mark; /* mark of SDB not marked full */ 84 unsigned long *sdb_index; /* SDB address for fast lookup */ 85 unsigned long *sdbt_index; /* SDBT address for fast lookup */ 86 }; 87 88 struct cpu_hw_sf { 89 /* CPU-measurement sampling information block */ 90 struct hws_qsi_info_block qsi; 91 /* CPU-measurement sampling control block */ 92 struct hws_lsctl_request_block lsctl; 93 struct sf_buffer sfb; /* Sampling buffer */ 94 unsigned int flags; /* Status flags */ 95 struct perf_event *event; /* Scheduled perf event */ 96 struct perf_output_handle handle; /* AUX buffer output handle */ 97 }; 98 static DEFINE_PER_CPU(struct cpu_hw_sf, cpu_hw_sf); 99 100 /* Debug feature */ 101 static debug_info_t *sfdbg; 102 103 /* Sampling control helper functions */ 104 static inline unsigned long freq_to_sample_rate(struct hws_qsi_info_block *qsi, 105 unsigned long freq) 106 { 107 return (USEC_PER_SEC / freq) * qsi->cpu_speed; 108 } 109 110 static inline unsigned long sample_rate_to_freq(struct hws_qsi_info_block *qsi, 111 unsigned long rate) 112 { 113 return USEC_PER_SEC * qsi->cpu_speed / rate; 114 } 115 116 /* Return TOD timestamp contained in an trailer entry */ 117 static inline unsigned long long trailer_timestamp(struct hws_trailer_entry *te) 118 { 119 /* TOD in STCKE format */ 120 if (te->header.t) 121 return *((unsigned long long *)&te->timestamp[1]); 122 123 /* TOD in STCK format */ 124 return *((unsigned long long *)&te->timestamp[0]); 125 } 126 127 /* Return pointer to trailer entry of an sample data block */ 128 static inline struct hws_trailer_entry *trailer_entry_ptr(unsigned long v) 129 { 130 void *ret; 131 132 ret = (void *)v; 133 ret += PAGE_SIZE; 134 ret -= sizeof(struct hws_trailer_entry); 135 136 return ret; 137 } 138 139 /* 140 * Return true if the entry in the sample data block table (sdbt) 141 * is a link to the next sdbt 142 */ 143 static inline int is_link_entry(unsigned long *s) 144 { 145 return *s & 0x1UL ? 1 : 0; 146 } 147 148 /* Return pointer to the linked sdbt */ 149 static inline unsigned long *get_next_sdbt(unsigned long *s) 150 { 151 return phys_to_virt(*s & ~0x1UL); 152 } 153 154 /* 155 * sf_disable() - Switch off sampling facility 156 */ 157 static int sf_disable(void) 158 { 159 struct hws_lsctl_request_block sreq; 160 161 memset(&sreq, 0, sizeof(sreq)); 162 return lsctl(&sreq); 163 } 164 165 /* 166 * sf_buffer_available() - Check for an allocated sampling buffer 167 */ 168 static int sf_buffer_available(struct cpu_hw_sf *cpuhw) 169 { 170 return !!cpuhw->sfb.sdbt; 171 } 172 173 /* 174 * deallocate sampling facility buffer 175 */ 176 static void free_sampling_buffer(struct sf_buffer *sfb) 177 { 178 unsigned long *sdbt, *curr; 179 180 if (!sfb->sdbt) 181 return; 182 183 sdbt = sfb->sdbt; 184 curr = sdbt; 185 186 /* Free the SDBT after all SDBs are processed... */ 187 while (1) { 188 if (!*curr || !sdbt) 189 break; 190 191 /* Process table-link entries */ 192 if (is_link_entry(curr)) { 193 curr = get_next_sdbt(curr); 194 if (sdbt) 195 free_page((unsigned long) sdbt); 196 197 /* If the origin is reached, sampling buffer is freed */ 198 if (curr == sfb->sdbt) 199 break; 200 else 201 sdbt = curr; 202 } else { 203 /* Process SDB pointer */ 204 if (*curr) { 205 free_page((unsigned long)phys_to_virt(*curr)); 206 curr++; 207 } 208 } 209 } 210 211 debug_sprintf_event(sfdbg, 5, "%s: freed sdbt %#lx\n", __func__, 212 (unsigned long)sfb->sdbt); 213 memset(sfb, 0, sizeof(*sfb)); 214 } 215 216 static int alloc_sample_data_block(unsigned long *sdbt, gfp_t gfp_flags) 217 { 218 struct hws_trailer_entry *te; 219 unsigned long sdb; 220 221 /* Allocate and initialize sample-data-block */ 222 sdb = get_zeroed_page(gfp_flags); 223 if (!sdb) 224 return -ENOMEM; 225 te = trailer_entry_ptr(sdb); 226 te->header.a = 1; 227 228 /* Link SDB into the sample-data-block-table */ 229 *sdbt = virt_to_phys((void *)sdb); 230 231 return 0; 232 } 233 234 /* 235 * realloc_sampling_buffer() - extend sampler memory 236 * 237 * Allocates new sample-data-blocks and adds them to the specified sampling 238 * buffer memory. 239 * 240 * Important: This modifies the sampling buffer and must be called when the 241 * sampling facility is disabled. 242 * 243 * Returns zero on success, non-zero otherwise. 244 */ 245 static int realloc_sampling_buffer(struct sf_buffer *sfb, 246 unsigned long num_sdb, gfp_t gfp_flags) 247 { 248 int i, rc; 249 unsigned long *new, *tail, *tail_prev = NULL; 250 251 if (!sfb->sdbt || !sfb->tail) 252 return -EINVAL; 253 254 if (!is_link_entry(sfb->tail)) 255 return -EINVAL; 256 257 /* Append to the existing sampling buffer, overwriting the table-link 258 * register. 259 * The tail variables always points to the "tail" (last and table-link) 260 * entry in an SDB-table. 261 */ 262 tail = sfb->tail; 263 264 /* Do a sanity check whether the table-link entry points to 265 * the sampling buffer origin. 266 */ 267 if (sfb->sdbt != get_next_sdbt(tail)) { 268 debug_sprintf_event(sfdbg, 3, "%s: " 269 "sampling buffer is not linked: origin %#lx" 270 " tail %#lx\n", __func__, 271 (unsigned long)sfb->sdbt, 272 (unsigned long)tail); 273 return -EINVAL; 274 } 275 276 /* Allocate remaining SDBs */ 277 rc = 0; 278 for (i = 0; i < num_sdb; i++) { 279 /* Allocate a new SDB-table if it is full. */ 280 if (require_table_link(tail)) { 281 new = (unsigned long *) get_zeroed_page(gfp_flags); 282 if (!new) { 283 rc = -ENOMEM; 284 break; 285 } 286 sfb->num_sdbt++; 287 /* Link current page to tail of chain */ 288 *tail = virt_to_phys((void *)new) + 1; 289 tail_prev = tail; 290 tail = new; 291 } 292 293 /* Allocate a new sample-data-block. 294 * If there is not enough memory, stop the realloc process 295 * and simply use what was allocated. If this is a temporary 296 * issue, a new realloc call (if required) might succeed. 297 */ 298 rc = alloc_sample_data_block(tail, gfp_flags); 299 if (rc) { 300 /* Undo last SDBT. An SDBT with no SDB at its first 301 * entry but with an SDBT entry instead can not be 302 * handled by the interrupt handler code. 303 * Avoid this situation. 304 */ 305 if (tail_prev) { 306 sfb->num_sdbt--; 307 free_page((unsigned long) new); 308 tail = tail_prev; 309 } 310 break; 311 } 312 sfb->num_sdb++; 313 tail++; 314 tail_prev = new = NULL; /* Allocated at least one SBD */ 315 } 316 317 /* Link sampling buffer to its origin */ 318 *tail = virt_to_phys(sfb->sdbt) + 1; 319 sfb->tail = tail; 320 321 debug_sprintf_event(sfdbg, 4, "%s: new buffer" 322 " settings: sdbt %lu sdb %lu\n", __func__, 323 sfb->num_sdbt, sfb->num_sdb); 324 return rc; 325 } 326 327 /* 328 * allocate_sampling_buffer() - allocate sampler memory 329 * 330 * Allocates and initializes a sampling buffer structure using the 331 * specified number of sample-data-blocks (SDB). For each allocation, 332 * a 4K page is used. The number of sample-data-block-tables (SDBT) 333 * are calculated from SDBs. 334 * Also set the ALERT_REQ mask in each SDBs trailer. 335 * 336 * Returns zero on success, non-zero otherwise. 337 */ 338 static int alloc_sampling_buffer(struct sf_buffer *sfb, unsigned long num_sdb) 339 { 340 int rc; 341 342 if (sfb->sdbt) 343 return -EINVAL; 344 345 /* Allocate the sample-data-block-table origin */ 346 sfb->sdbt = (unsigned long *) get_zeroed_page(GFP_KERNEL); 347 if (!sfb->sdbt) 348 return -ENOMEM; 349 sfb->num_sdb = 0; 350 sfb->num_sdbt = 1; 351 352 /* Link the table origin to point to itself to prepare for 353 * realloc_sampling_buffer() invocation. 354 */ 355 sfb->tail = sfb->sdbt; 356 *sfb->tail = virt_to_phys((void *)sfb->sdbt) + 1; 357 358 /* Allocate requested number of sample-data-blocks */ 359 rc = realloc_sampling_buffer(sfb, num_sdb, GFP_KERNEL); 360 if (rc) { 361 free_sampling_buffer(sfb); 362 debug_sprintf_event(sfdbg, 4, "%s: " 363 "realloc_sampling_buffer failed with rc %i\n", 364 __func__, rc); 365 } else 366 debug_sprintf_event(sfdbg, 4, 367 "%s: tear %#lx dear %#lx\n", __func__, 368 (unsigned long)sfb->sdbt, (unsigned long)*sfb->sdbt); 369 return rc; 370 } 371 372 static void sfb_set_limits(unsigned long min, unsigned long max) 373 { 374 struct hws_qsi_info_block si; 375 376 CPUM_SF_MIN_SDB = min; 377 CPUM_SF_MAX_SDB = max; 378 379 memset(&si, 0, sizeof(si)); 380 if (!qsi(&si)) 381 CPUM_SF_SDB_DIAG_FACTOR = DIV_ROUND_UP(si.dsdes, si.bsdes); 382 } 383 384 static unsigned long sfb_max_limit(struct hw_perf_event *hwc) 385 { 386 return SAMPL_DIAG_MODE(hwc) ? CPUM_SF_MAX_SDB * CPUM_SF_SDB_DIAG_FACTOR 387 : CPUM_SF_MAX_SDB; 388 } 389 390 static unsigned long sfb_pending_allocs(struct sf_buffer *sfb, 391 struct hw_perf_event *hwc) 392 { 393 if (!sfb->sdbt) 394 return SFB_ALLOC_REG(hwc); 395 if (SFB_ALLOC_REG(hwc) > sfb->num_sdb) 396 return SFB_ALLOC_REG(hwc) - sfb->num_sdb; 397 return 0; 398 } 399 400 static int sfb_has_pending_allocs(struct sf_buffer *sfb, 401 struct hw_perf_event *hwc) 402 { 403 return sfb_pending_allocs(sfb, hwc) > 0; 404 } 405 406 static void sfb_account_allocs(unsigned long num, struct hw_perf_event *hwc) 407 { 408 /* Limit the number of SDBs to not exceed the maximum */ 409 num = min_t(unsigned long, num, sfb_max_limit(hwc) - SFB_ALLOC_REG(hwc)); 410 if (num) 411 SFB_ALLOC_REG(hwc) += num; 412 } 413 414 static void sfb_init_allocs(unsigned long num, struct hw_perf_event *hwc) 415 { 416 SFB_ALLOC_REG(hwc) = 0; 417 sfb_account_allocs(num, hwc); 418 } 419 420 static void deallocate_buffers(struct cpu_hw_sf *cpuhw) 421 { 422 if (cpuhw->sfb.sdbt) 423 free_sampling_buffer(&cpuhw->sfb); 424 } 425 426 static int allocate_buffers(struct cpu_hw_sf *cpuhw, struct hw_perf_event *hwc) 427 { 428 unsigned long n_sdb, freq; 429 size_t sample_size; 430 431 /* Calculate sampling buffers using 4K pages 432 * 433 * 1. The sampling size is 32 bytes for basic sampling. This size 434 * is the same for all machine types. Diagnostic 435 * sampling uses auxlilary data buffer setup which provides the 436 * memory for SDBs using linux common code auxiliary trace 437 * setup. 438 * 439 * 2. Function alloc_sampling_buffer() sets the Alert Request 440 * Control indicator to trigger a measurement-alert to harvest 441 * sample-data-blocks (SDB). This is done per SDB. This 442 * measurement alert interrupt fires quick enough to handle 443 * one SDB, on very high frequency and work loads there might 444 * be 2 to 3 SBDs available for sample processing. 445 * Currently there is no need for setup alert request on every 446 * n-th page. This is counterproductive as one IRQ triggers 447 * a very high number of samples to be processed at one IRQ. 448 * 449 * 3. Use the sampling frequency as input. 450 * Compute the number of SDBs and ensure a minimum 451 * of CPUM_SF_MIN_SDB. Depending on frequency add some more 452 * SDBs to handle a higher sampling rate. 453 * Use a minimum of CPUM_SF_MIN_SDB and allow for 100 samples 454 * (one SDB) for every 10000 HZ frequency increment. 455 * 456 * 4. Compute the number of sample-data-block-tables (SDBT) and 457 * ensure a minimum of CPUM_SF_MIN_SDBT (one table can manage up 458 * to 511 SDBs). 459 */ 460 sample_size = sizeof(struct hws_basic_entry); 461 freq = sample_rate_to_freq(&cpuhw->qsi, SAMPL_RATE(hwc)); 462 n_sdb = CPUM_SF_MIN_SDB + DIV_ROUND_UP(freq, 10000); 463 464 /* If there is already a sampling buffer allocated, it is very likely 465 * that the sampling facility is enabled too. If the event to be 466 * initialized requires a greater sampling buffer, the allocation must 467 * be postponed. Changing the sampling buffer requires the sampling 468 * facility to be in the disabled state. So, account the number of 469 * required SDBs and let cpumsf_pmu_enable() resize the buffer just 470 * before the event is started. 471 */ 472 sfb_init_allocs(n_sdb, hwc); 473 if (sf_buffer_available(cpuhw)) 474 return 0; 475 476 debug_sprintf_event(sfdbg, 3, 477 "%s: rate %lu f %lu sdb %lu/%lu" 478 " sample_size %lu cpuhw %p\n", __func__, 479 SAMPL_RATE(hwc), freq, n_sdb, sfb_max_limit(hwc), 480 sample_size, cpuhw); 481 482 return alloc_sampling_buffer(&cpuhw->sfb, 483 sfb_pending_allocs(&cpuhw->sfb, hwc)); 484 } 485 486 static unsigned long min_percent(unsigned int percent, unsigned long base, 487 unsigned long min) 488 { 489 return min_t(unsigned long, min, DIV_ROUND_UP(percent * base, 100)); 490 } 491 492 static unsigned long compute_sfb_extent(unsigned long ratio, unsigned long base) 493 { 494 /* Use a percentage-based approach to extend the sampling facility 495 * buffer. Accept up to 5% sample data loss. 496 * Vary the extents between 1% to 5% of the current number of 497 * sample-data-blocks. 498 */ 499 if (ratio <= 5) 500 return 0; 501 if (ratio <= 25) 502 return min_percent(1, base, 1); 503 if (ratio <= 50) 504 return min_percent(1, base, 1); 505 if (ratio <= 75) 506 return min_percent(2, base, 2); 507 if (ratio <= 100) 508 return min_percent(3, base, 3); 509 if (ratio <= 250) 510 return min_percent(4, base, 4); 511 512 return min_percent(5, base, 8); 513 } 514 515 static void sfb_account_overflows(struct cpu_hw_sf *cpuhw, 516 struct hw_perf_event *hwc) 517 { 518 unsigned long ratio, num; 519 520 if (!OVERFLOW_REG(hwc)) 521 return; 522 523 /* The sample_overflow contains the average number of sample data 524 * that has been lost because sample-data-blocks were full. 525 * 526 * Calculate the total number of sample data entries that has been 527 * discarded. Then calculate the ratio of lost samples to total samples 528 * per second in percent. 529 */ 530 ratio = DIV_ROUND_UP(100 * OVERFLOW_REG(hwc) * cpuhw->sfb.num_sdb, 531 sample_rate_to_freq(&cpuhw->qsi, SAMPL_RATE(hwc))); 532 533 /* Compute number of sample-data-blocks */ 534 num = compute_sfb_extent(ratio, cpuhw->sfb.num_sdb); 535 if (num) 536 sfb_account_allocs(num, hwc); 537 538 debug_sprintf_event(sfdbg, 5, "%s: overflow %llu ratio %lu num %lu\n", 539 __func__, OVERFLOW_REG(hwc), ratio, num); 540 OVERFLOW_REG(hwc) = 0; 541 } 542 543 /* extend_sampling_buffer() - Extend sampling buffer 544 * @sfb: Sampling buffer structure (for local CPU) 545 * @hwc: Perf event hardware structure 546 * 547 * Use this function to extend the sampling buffer based on the overflow counter 548 * and postponed allocation extents stored in the specified Perf event hardware. 549 * 550 * Important: This function disables the sampling facility in order to safely 551 * change the sampling buffer structure. Do not call this function 552 * when the PMU is active. 553 */ 554 static void extend_sampling_buffer(struct sf_buffer *sfb, 555 struct hw_perf_event *hwc) 556 { 557 unsigned long num, num_old; 558 int rc; 559 560 num = sfb_pending_allocs(sfb, hwc); 561 if (!num) 562 return; 563 num_old = sfb->num_sdb; 564 565 /* Disable the sampling facility to reset any states and also 566 * clear pending measurement alerts. 567 */ 568 sf_disable(); 569 570 /* Extend the sampling buffer. 571 * This memory allocation typically happens in an atomic context when 572 * called by perf. Because this is a reallocation, it is fine if the 573 * new SDB-request cannot be satisfied immediately. 574 */ 575 rc = realloc_sampling_buffer(sfb, num, GFP_ATOMIC); 576 if (rc) 577 debug_sprintf_event(sfdbg, 5, "%s: realloc failed with rc %i\n", 578 __func__, rc); 579 580 if (sfb_has_pending_allocs(sfb, hwc)) 581 debug_sprintf_event(sfdbg, 5, "%s: " 582 "req %lu alloc %lu remaining %lu\n", 583 __func__, num, sfb->num_sdb - num_old, 584 sfb_pending_allocs(sfb, hwc)); 585 } 586 587 /* Number of perf events counting hardware events */ 588 static atomic_t num_events; 589 /* Used to avoid races in calling reserve/release_cpumf_hardware */ 590 static DEFINE_MUTEX(pmc_reserve_mutex); 591 592 #define PMC_INIT 0 593 #define PMC_RELEASE 1 594 #define PMC_FAILURE 2 595 static void setup_pmc_cpu(void *flags) 596 { 597 int err; 598 struct cpu_hw_sf *cpusf = this_cpu_ptr(&cpu_hw_sf); 599 600 err = 0; 601 switch (*((int *) flags)) { 602 case PMC_INIT: 603 memset(cpusf, 0, sizeof(*cpusf)); 604 err = qsi(&cpusf->qsi); 605 if (err) 606 break; 607 cpusf->flags |= PMU_F_RESERVED; 608 err = sf_disable(); 609 if (err) 610 pr_err("Switching off the sampling facility failed " 611 "with rc %i\n", err); 612 break; 613 case PMC_RELEASE: 614 cpusf->flags &= ~PMU_F_RESERVED; 615 err = sf_disable(); 616 if (err) { 617 pr_err("Switching off the sampling facility failed " 618 "with rc %i\n", err); 619 } else 620 deallocate_buffers(cpusf); 621 break; 622 } 623 if (err) 624 *((int *) flags) |= PMC_FAILURE; 625 } 626 627 static void release_pmc_hardware(void) 628 { 629 int flags = PMC_RELEASE; 630 631 irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT); 632 on_each_cpu(setup_pmc_cpu, &flags, 1); 633 } 634 635 static int reserve_pmc_hardware(void) 636 { 637 int flags = PMC_INIT; 638 639 on_each_cpu(setup_pmc_cpu, &flags, 1); 640 if (flags & PMC_FAILURE) { 641 release_pmc_hardware(); 642 return -ENODEV; 643 } 644 irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT); 645 646 return 0; 647 } 648 649 static void hw_perf_event_destroy(struct perf_event *event) 650 { 651 /* Release PMC if this is the last perf event */ 652 if (!atomic_add_unless(&num_events, -1, 1)) { 653 mutex_lock(&pmc_reserve_mutex); 654 if (atomic_dec_return(&num_events) == 0) 655 release_pmc_hardware(); 656 mutex_unlock(&pmc_reserve_mutex); 657 } 658 } 659 660 static void hw_init_period(struct hw_perf_event *hwc, u64 period) 661 { 662 hwc->sample_period = period; 663 hwc->last_period = hwc->sample_period; 664 local64_set(&hwc->period_left, hwc->sample_period); 665 } 666 667 static unsigned long hw_limit_rate(const struct hws_qsi_info_block *si, 668 unsigned long rate) 669 { 670 return clamp_t(unsigned long, rate, 671 si->min_sampl_rate, si->max_sampl_rate); 672 } 673 674 static u32 cpumsf_pid_type(struct perf_event *event, 675 u32 pid, enum pid_type type) 676 { 677 struct task_struct *tsk; 678 679 /* Idle process */ 680 if (!pid) 681 goto out; 682 683 tsk = find_task_by_pid_ns(pid, &init_pid_ns); 684 pid = -1; 685 if (tsk) { 686 /* 687 * Only top level events contain the pid namespace in which 688 * they are created. 689 */ 690 if (event->parent) 691 event = event->parent; 692 pid = __task_pid_nr_ns(tsk, type, event->ns); 693 /* 694 * See also 1d953111b648 695 * "perf/core: Don't report zero PIDs for exiting tasks". 696 */ 697 if (!pid && !pid_alive(tsk)) 698 pid = -1; 699 } 700 out: 701 return pid; 702 } 703 704 static void cpumsf_output_event_pid(struct perf_event *event, 705 struct perf_sample_data *data, 706 struct pt_regs *regs) 707 { 708 u32 pid; 709 struct perf_event_header header; 710 struct perf_output_handle handle; 711 712 /* 713 * Obtain the PID from the basic-sampling data entry and 714 * correct the data->tid_entry.pid value. 715 */ 716 pid = data->tid_entry.pid; 717 718 /* Protect callchain buffers, tasks */ 719 rcu_read_lock(); 720 721 perf_prepare_sample(data, event, regs); 722 perf_prepare_header(&header, data, event, regs); 723 if (perf_output_begin(&handle, data, event, header.size)) 724 goto out; 725 726 /* Update the process ID (see also kernel/events/core.c) */ 727 data->tid_entry.pid = cpumsf_pid_type(event, pid, PIDTYPE_TGID); 728 data->tid_entry.tid = cpumsf_pid_type(event, pid, PIDTYPE_PID); 729 730 perf_output_sample(&handle, &header, data, event); 731 perf_output_end(&handle); 732 out: 733 rcu_read_unlock(); 734 } 735 736 static unsigned long getrate(bool freq, unsigned long sample, 737 struct hws_qsi_info_block *si) 738 { 739 unsigned long rate; 740 741 if (freq) { 742 rate = freq_to_sample_rate(si, sample); 743 rate = hw_limit_rate(si, rate); 744 } else { 745 /* The min/max sampling rates specifies the valid range 746 * of sample periods. If the specified sample period is 747 * out of range, limit the period to the range boundary. 748 */ 749 rate = hw_limit_rate(si, sample); 750 751 /* The perf core maintains a maximum sample rate that is 752 * configurable through the sysctl interface. Ensure the 753 * sampling rate does not exceed this value. This also helps 754 * to avoid throttling when pushing samples with 755 * perf_event_overflow(). 756 */ 757 if (sample_rate_to_freq(si, rate) > 758 sysctl_perf_event_sample_rate) { 759 debug_sprintf_event(sfdbg, 1, "%s: " 760 "Sampling rate exceeds maximum " 761 "perf sample rate\n", __func__); 762 rate = 0; 763 } 764 } 765 return rate; 766 } 767 768 /* The sampling information (si) contains information about the 769 * min/max sampling intervals and the CPU speed. So calculate the 770 * correct sampling interval and avoid the whole period adjust 771 * feedback loop. 772 * 773 * Since the CPU Measurement sampling facility can not handle frequency 774 * calculate the sampling interval when frequency is specified using 775 * this formula: 776 * interval := cpu_speed * 1000000 / sample_freq 777 * 778 * Returns errno on bad input and zero on success with parameter interval 779 * set to the correct sampling rate. 780 * 781 * Note: This function turns off freq bit to avoid calling function 782 * perf_adjust_period(). This causes frequency adjustment in the common 783 * code part which causes tremendous variations in the counter values. 784 */ 785 static int __hw_perf_event_init_rate(struct perf_event *event, 786 struct hws_qsi_info_block *si) 787 { 788 struct perf_event_attr *attr = &event->attr; 789 struct hw_perf_event *hwc = &event->hw; 790 unsigned long rate; 791 792 if (attr->freq) { 793 if (!attr->sample_freq) 794 return -EINVAL; 795 rate = getrate(attr->freq, attr->sample_freq, si); 796 attr->freq = 0; /* Don't call perf_adjust_period() */ 797 SAMPL_FLAGS(hwc) |= PERF_CPUM_SF_FREQ_MODE; 798 } else { 799 rate = getrate(attr->freq, attr->sample_period, si); 800 if (!rate) 801 return -EINVAL; 802 } 803 attr->sample_period = rate; 804 SAMPL_RATE(hwc) = rate; 805 hw_init_period(hwc, SAMPL_RATE(hwc)); 806 debug_sprintf_event(sfdbg, 4, "%s: cpu %d period %#llx freq %d,%#lx\n", 807 __func__, event->cpu, event->attr.sample_period, 808 event->attr.freq, SAMPLE_FREQ_MODE(hwc)); 809 return 0; 810 } 811 812 static int __hw_perf_event_init(struct perf_event *event) 813 { 814 struct cpu_hw_sf *cpuhw; 815 struct hws_qsi_info_block si; 816 struct perf_event_attr *attr = &event->attr; 817 struct hw_perf_event *hwc = &event->hw; 818 int cpu, err; 819 820 /* Reserve CPU-measurement sampling facility */ 821 err = 0; 822 if (!atomic_inc_not_zero(&num_events)) { 823 mutex_lock(&pmc_reserve_mutex); 824 if (atomic_read(&num_events) == 0 && reserve_pmc_hardware()) 825 err = -EBUSY; 826 else 827 atomic_inc(&num_events); 828 mutex_unlock(&pmc_reserve_mutex); 829 } 830 event->destroy = hw_perf_event_destroy; 831 832 if (err) 833 goto out; 834 835 /* Access per-CPU sampling information (query sampling info) */ 836 /* 837 * The event->cpu value can be -1 to count on every CPU, for example, 838 * when attaching to a task. If this is specified, use the query 839 * sampling info from the current CPU, otherwise use event->cpu to 840 * retrieve the per-CPU information. 841 * Later, cpuhw indicates whether to allocate sampling buffers for a 842 * particular CPU (cpuhw!=NULL) or each online CPU (cpuw==NULL). 843 */ 844 memset(&si, 0, sizeof(si)); 845 cpuhw = NULL; 846 if (event->cpu == -1) 847 qsi(&si); 848 else { 849 /* Event is pinned to a particular CPU, retrieve the per-CPU 850 * sampling structure for accessing the CPU-specific QSI. 851 */ 852 cpuhw = &per_cpu(cpu_hw_sf, event->cpu); 853 si = cpuhw->qsi; 854 } 855 856 /* Check sampling facility authorization and, if not authorized, 857 * fall back to other PMUs. It is safe to check any CPU because 858 * the authorization is identical for all configured CPUs. 859 */ 860 if (!si.as) { 861 err = -ENOENT; 862 goto out; 863 } 864 865 if (si.ribm & CPU_MF_SF_RIBM_NOTAV) { 866 pr_warn("CPU Measurement Facility sampling is temporarily not available\n"); 867 err = -EBUSY; 868 goto out; 869 } 870 871 /* Always enable basic sampling */ 872 SAMPL_FLAGS(hwc) = PERF_CPUM_SF_BASIC_MODE; 873 874 /* Check if diagnostic sampling is requested. Deny if the required 875 * sampling authorization is missing. 876 */ 877 if (attr->config == PERF_EVENT_CPUM_SF_DIAG) { 878 if (!si.ad) { 879 err = -EPERM; 880 goto out; 881 } 882 SAMPL_FLAGS(hwc) |= PERF_CPUM_SF_DIAG_MODE; 883 } 884 885 /* Check and set other sampling flags */ 886 if (attr->config1 & PERF_CPUM_SF_FULL_BLOCKS) 887 SAMPL_FLAGS(hwc) |= PERF_CPUM_SF_FULL_BLOCKS; 888 889 err = __hw_perf_event_init_rate(event, &si); 890 if (err) 891 goto out; 892 893 /* Initialize sample data overflow accounting */ 894 hwc->extra_reg.reg = REG_OVERFLOW; 895 OVERFLOW_REG(hwc) = 0; 896 897 /* Use AUX buffer. No need to allocate it by ourself */ 898 if (attr->config == PERF_EVENT_CPUM_SF_DIAG) 899 return 0; 900 901 /* Allocate the per-CPU sampling buffer using the CPU information 902 * from the event. If the event is not pinned to a particular 903 * CPU (event->cpu == -1; or cpuhw == NULL), allocate sampling 904 * buffers for each online CPU. 905 */ 906 if (cpuhw) 907 /* Event is pinned to a particular CPU */ 908 err = allocate_buffers(cpuhw, hwc); 909 else { 910 /* Event is not pinned, allocate sampling buffer on 911 * each online CPU 912 */ 913 for_each_online_cpu(cpu) { 914 cpuhw = &per_cpu(cpu_hw_sf, cpu); 915 err = allocate_buffers(cpuhw, hwc); 916 if (err) 917 break; 918 } 919 } 920 921 /* If PID/TID sampling is active, replace the default overflow 922 * handler to extract and resolve the PIDs from the basic-sampling 923 * data entries. 924 */ 925 if (event->attr.sample_type & PERF_SAMPLE_TID) 926 if (is_default_overflow_handler(event)) 927 event->overflow_handler = cpumsf_output_event_pid; 928 out: 929 return err; 930 } 931 932 static bool is_callchain_event(struct perf_event *event) 933 { 934 u64 sample_type = event->attr.sample_type; 935 936 return sample_type & (PERF_SAMPLE_CALLCHAIN | PERF_SAMPLE_REGS_USER | 937 PERF_SAMPLE_STACK_USER); 938 } 939 940 static int cpumsf_pmu_event_init(struct perf_event *event) 941 { 942 int err; 943 944 /* No support for taken branch sampling */ 945 /* No support for callchain, stacks and registers */ 946 if (has_branch_stack(event) || is_callchain_event(event)) 947 return -EOPNOTSUPP; 948 949 switch (event->attr.type) { 950 case PERF_TYPE_RAW: 951 if ((event->attr.config != PERF_EVENT_CPUM_SF) && 952 (event->attr.config != PERF_EVENT_CPUM_SF_DIAG)) 953 return -ENOENT; 954 break; 955 case PERF_TYPE_HARDWARE: 956 /* Support sampling of CPU cycles in addition to the 957 * counter facility. However, the counter facility 958 * is more precise and, hence, restrict this PMU to 959 * sampling events only. 960 */ 961 if (event->attr.config != PERF_COUNT_HW_CPU_CYCLES) 962 return -ENOENT; 963 if (!is_sampling_event(event)) 964 return -ENOENT; 965 break; 966 default: 967 return -ENOENT; 968 } 969 970 /* Check online status of the CPU to which the event is pinned */ 971 if (event->cpu >= 0 && !cpu_online(event->cpu)) 972 return -ENODEV; 973 974 /* Force reset of idle/hv excludes regardless of what the 975 * user requested. 976 */ 977 if (event->attr.exclude_hv) 978 event->attr.exclude_hv = 0; 979 if (event->attr.exclude_idle) 980 event->attr.exclude_idle = 0; 981 982 err = __hw_perf_event_init(event); 983 if (unlikely(err)) 984 if (event->destroy) 985 event->destroy(event); 986 return err; 987 } 988 989 static void cpumsf_pmu_enable(struct pmu *pmu) 990 { 991 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 992 struct hw_perf_event *hwc; 993 int err; 994 995 if (cpuhw->flags & PMU_F_ENABLED) 996 return; 997 998 if (cpuhw->flags & PMU_F_ERR_MASK) 999 return; 1000 1001 /* Check whether to extent the sampling buffer. 1002 * 1003 * Two conditions trigger an increase of the sampling buffer for a 1004 * perf event: 1005 * 1. Postponed buffer allocations from the event initialization. 1006 * 2. Sampling overflows that contribute to pending allocations. 1007 * 1008 * Note that the extend_sampling_buffer() function disables the sampling 1009 * facility, but it can be fully re-enabled using sampling controls that 1010 * have been saved in cpumsf_pmu_disable(). 1011 */ 1012 if (cpuhw->event) { 1013 hwc = &cpuhw->event->hw; 1014 if (!(SAMPL_DIAG_MODE(hwc))) { 1015 /* 1016 * Account number of overflow-designated 1017 * buffer extents 1018 */ 1019 sfb_account_overflows(cpuhw, hwc); 1020 extend_sampling_buffer(&cpuhw->sfb, hwc); 1021 } 1022 /* Rate may be adjusted with ioctl() */ 1023 cpuhw->lsctl.interval = SAMPL_RATE(&cpuhw->event->hw); 1024 } 1025 1026 /* (Re)enable the PMU and sampling facility */ 1027 cpuhw->flags |= PMU_F_ENABLED; 1028 barrier(); 1029 1030 err = lsctl(&cpuhw->lsctl); 1031 if (err) { 1032 cpuhw->flags &= ~PMU_F_ENABLED; 1033 pr_err("Loading sampling controls failed: op %i err %i\n", 1034 1, err); 1035 return; 1036 } 1037 1038 /* Load current program parameter */ 1039 lpp(&S390_lowcore.lpp); 1040 1041 debug_sprintf_event(sfdbg, 6, "%s: es %i cs %i ed %i cd %i " 1042 "interval %#lx tear %#lx dear %#lx\n", __func__, 1043 cpuhw->lsctl.es, cpuhw->lsctl.cs, cpuhw->lsctl.ed, 1044 cpuhw->lsctl.cd, cpuhw->lsctl.interval, 1045 cpuhw->lsctl.tear, cpuhw->lsctl.dear); 1046 } 1047 1048 static void cpumsf_pmu_disable(struct pmu *pmu) 1049 { 1050 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 1051 struct hws_lsctl_request_block inactive; 1052 struct hws_qsi_info_block si; 1053 int err; 1054 1055 if (!(cpuhw->flags & PMU_F_ENABLED)) 1056 return; 1057 1058 if (cpuhw->flags & PMU_F_ERR_MASK) 1059 return; 1060 1061 /* Switch off sampling activation control */ 1062 inactive = cpuhw->lsctl; 1063 inactive.cs = 0; 1064 inactive.cd = 0; 1065 1066 err = lsctl(&inactive); 1067 if (err) { 1068 pr_err("Loading sampling controls failed: op %i err %i\n", 1069 2, err); 1070 return; 1071 } 1072 1073 /* Save state of TEAR and DEAR register contents */ 1074 err = qsi(&si); 1075 if (!err) { 1076 /* TEAR/DEAR values are valid only if the sampling facility is 1077 * enabled. Note that cpumsf_pmu_disable() might be called even 1078 * for a disabled sampling facility because cpumsf_pmu_enable() 1079 * controls the enable/disable state. 1080 */ 1081 if (si.es) { 1082 cpuhw->lsctl.tear = si.tear; 1083 cpuhw->lsctl.dear = si.dear; 1084 } 1085 } else 1086 debug_sprintf_event(sfdbg, 3, "%s: qsi() failed with err %i\n", 1087 __func__, err); 1088 1089 cpuhw->flags &= ~PMU_F_ENABLED; 1090 } 1091 1092 /* perf_exclude_event() - Filter event 1093 * @event: The perf event 1094 * @regs: pt_regs structure 1095 * @sde_regs: Sample-data-entry (sde) regs structure 1096 * 1097 * Filter perf events according to their exclude specification. 1098 * 1099 * Return non-zero if the event shall be excluded. 1100 */ 1101 static int perf_exclude_event(struct perf_event *event, struct pt_regs *regs, 1102 struct perf_sf_sde_regs *sde_regs) 1103 { 1104 if (event->attr.exclude_user && user_mode(regs)) 1105 return 1; 1106 if (event->attr.exclude_kernel && !user_mode(regs)) 1107 return 1; 1108 if (event->attr.exclude_guest && sde_regs->in_guest) 1109 return 1; 1110 if (event->attr.exclude_host && !sde_regs->in_guest) 1111 return 1; 1112 return 0; 1113 } 1114 1115 /* perf_push_sample() - Push samples to perf 1116 * @event: The perf event 1117 * @sample: Hardware sample data 1118 * 1119 * Use the hardware sample data to create perf event sample. The sample 1120 * is the pushed to the event subsystem and the function checks for 1121 * possible event overflows. If an event overflow occurs, the PMU is 1122 * stopped. 1123 * 1124 * Return non-zero if an event overflow occurred. 1125 */ 1126 static int perf_push_sample(struct perf_event *event, 1127 struct hws_basic_entry *basic) 1128 { 1129 int overflow; 1130 struct pt_regs regs; 1131 struct perf_sf_sde_regs *sde_regs; 1132 struct perf_sample_data data; 1133 1134 /* Setup perf sample */ 1135 perf_sample_data_init(&data, 0, event->hw.last_period); 1136 1137 /* Setup pt_regs to look like an CPU-measurement external interrupt 1138 * using the Program Request Alert code. The regs.int_parm_long 1139 * field which is unused contains additional sample-data-entry related 1140 * indicators. 1141 */ 1142 memset(®s, 0, sizeof(regs)); 1143 regs.int_code = 0x1407; 1144 regs.int_parm = CPU_MF_INT_SF_PRA; 1145 sde_regs = (struct perf_sf_sde_regs *) ®s.int_parm_long; 1146 1147 psw_bits(regs.psw).ia = basic->ia; 1148 psw_bits(regs.psw).dat = basic->T; 1149 psw_bits(regs.psw).wait = basic->W; 1150 psw_bits(regs.psw).pstate = basic->P; 1151 psw_bits(regs.psw).as = basic->AS; 1152 1153 /* 1154 * Use the hardware provided configuration level to decide if the 1155 * sample belongs to a guest or host. If that is not available, 1156 * fall back to the following heuristics: 1157 * A non-zero guest program parameter always indicates a guest 1158 * sample. Some early samples or samples from guests without 1159 * lpp usage would be misaccounted to the host. We use the asn 1160 * value as an addon heuristic to detect most of these guest samples. 1161 * If the value differs from 0xffff (the host value), we assume to 1162 * be a KVM guest. 1163 */ 1164 switch (basic->CL) { 1165 case 1: /* logical partition */ 1166 sde_regs->in_guest = 0; 1167 break; 1168 case 2: /* virtual machine */ 1169 sde_regs->in_guest = 1; 1170 break; 1171 default: /* old machine, use heuristics */ 1172 if (basic->gpp || basic->prim_asn != 0xffff) 1173 sde_regs->in_guest = 1; 1174 break; 1175 } 1176 1177 /* 1178 * Store the PID value from the sample-data-entry to be 1179 * processed and resolved by cpumsf_output_event_pid(). 1180 */ 1181 data.tid_entry.pid = basic->hpp & LPP_PID_MASK; 1182 1183 overflow = 0; 1184 if (perf_exclude_event(event, ®s, sde_regs)) 1185 goto out; 1186 if (perf_event_overflow(event, &data, ®s)) { 1187 overflow = 1; 1188 event->pmu->stop(event, 0); 1189 } 1190 perf_event_update_userpage(event); 1191 out: 1192 return overflow; 1193 } 1194 1195 static void perf_event_count_update(struct perf_event *event, u64 count) 1196 { 1197 local64_add(count, &event->count); 1198 } 1199 1200 /* hw_collect_samples() - Walk through a sample-data-block and collect samples 1201 * @event: The perf event 1202 * @sdbt: Sample-data-block table 1203 * @overflow: Event overflow counter 1204 * 1205 * Walks through a sample-data-block and collects sampling data entries that are 1206 * then pushed to the perf event subsystem. Depending on the sampling function, 1207 * there can be either basic-sampling or combined-sampling data entries. A 1208 * combined-sampling data entry consists of a basic- and a diagnostic-sampling 1209 * data entry. The sampling function is determined by the flags in the perf 1210 * event hardware structure. The function always works with a combined-sampling 1211 * data entry but ignores the the diagnostic portion if it is not available. 1212 * 1213 * Note that the implementation focuses on basic-sampling data entries and, if 1214 * such an entry is not valid, the entire combined-sampling data entry is 1215 * ignored. 1216 * 1217 * The overflow variables counts the number of samples that has been discarded 1218 * due to a perf event overflow. 1219 */ 1220 static void hw_collect_samples(struct perf_event *event, unsigned long *sdbt, 1221 unsigned long long *overflow) 1222 { 1223 struct hws_trailer_entry *te; 1224 struct hws_basic_entry *sample; 1225 1226 te = trailer_entry_ptr((unsigned long)sdbt); 1227 sample = (struct hws_basic_entry *)sdbt; 1228 while ((unsigned long *) sample < (unsigned long *) te) { 1229 /* Check for an empty sample */ 1230 if (!sample->def || sample->LS) 1231 break; 1232 1233 /* Update perf event period */ 1234 perf_event_count_update(event, SAMPL_RATE(&event->hw)); 1235 1236 /* Check whether sample is valid */ 1237 if (sample->def == 0x0001) { 1238 /* If an event overflow occurred, the PMU is stopped to 1239 * throttle event delivery. Remaining sample data is 1240 * discarded. 1241 */ 1242 if (!*overflow) { 1243 /* Check whether sample is consistent */ 1244 if (sample->I == 0 && sample->W == 0) { 1245 /* Deliver sample data to perf */ 1246 *overflow = perf_push_sample(event, 1247 sample); 1248 } 1249 } else 1250 /* Count discarded samples */ 1251 *overflow += 1; 1252 } else { 1253 debug_sprintf_event(sfdbg, 4, 1254 "%s: Found unknown" 1255 " sampling data entry: te->f %i" 1256 " basic.def %#4x (%p)\n", __func__, 1257 te->header.f, sample->def, sample); 1258 /* Sample slot is not yet written or other record. 1259 * 1260 * This condition can occur if the buffer was reused 1261 * from a combined basic- and diagnostic-sampling. 1262 * If only basic-sampling is then active, entries are 1263 * written into the larger diagnostic entries. 1264 * This is typically the case for sample-data-blocks 1265 * that are not full. Stop processing if the first 1266 * invalid format was detected. 1267 */ 1268 if (!te->header.f) 1269 break; 1270 } 1271 1272 /* Reset sample slot and advance to next sample */ 1273 sample->def = 0; 1274 sample++; 1275 } 1276 } 1277 1278 static inline __uint128_t __cdsg(__uint128_t *ptr, __uint128_t old, __uint128_t new) 1279 { 1280 asm volatile( 1281 " cdsg %[old],%[new],%[ptr]\n" 1282 : [old] "+d" (old), [ptr] "+QS" (*ptr) 1283 : [new] "d" (new) 1284 : "memory", "cc"); 1285 return old; 1286 } 1287 1288 /* hw_perf_event_update() - Process sampling buffer 1289 * @event: The perf event 1290 * @flush_all: Flag to also flush partially filled sample-data-blocks 1291 * 1292 * Processes the sampling buffer and create perf event samples. 1293 * The sampling buffer position are retrieved and saved in the TEAR_REG 1294 * register of the specified perf event. 1295 * 1296 * Only full sample-data-blocks are processed. Specify the flash_all flag 1297 * to also walk through partially filled sample-data-blocks. It is ignored 1298 * if PERF_CPUM_SF_FULL_BLOCKS is set. The PERF_CPUM_SF_FULL_BLOCKS flag 1299 * enforces the processing of full sample-data-blocks only (trailer entries 1300 * with the block-full-indicator bit set). 1301 */ 1302 static void hw_perf_event_update(struct perf_event *event, int flush_all) 1303 { 1304 unsigned long long event_overflow, sampl_overflow, num_sdb; 1305 union hws_trailer_header old, prev, new; 1306 struct hw_perf_event *hwc = &event->hw; 1307 struct hws_trailer_entry *te; 1308 unsigned long *sdbt, sdb; 1309 int done; 1310 1311 /* 1312 * AUX buffer is used when in diagnostic sampling mode. 1313 * No perf events/samples are created. 1314 */ 1315 if (SAMPL_DIAG_MODE(&event->hw)) 1316 return; 1317 1318 if (flush_all && SDB_FULL_BLOCKS(hwc)) 1319 flush_all = 0; 1320 1321 sdbt = (unsigned long *) TEAR_REG(hwc); 1322 done = event_overflow = sampl_overflow = num_sdb = 0; 1323 while (!done) { 1324 /* Get the trailer entry of the sample-data-block */ 1325 sdb = (unsigned long)phys_to_virt(*sdbt); 1326 te = trailer_entry_ptr(sdb); 1327 1328 /* Leave loop if no more work to do (block full indicator) */ 1329 if (!te->header.f) { 1330 done = 1; 1331 if (!flush_all) 1332 break; 1333 } 1334 1335 /* Check the sample overflow count */ 1336 if (te->header.overflow) 1337 /* Account sample overflows and, if a particular limit 1338 * is reached, extend the sampling buffer. 1339 * For details, see sfb_account_overflows(). 1340 */ 1341 sampl_overflow += te->header.overflow; 1342 1343 /* Timestamps are valid for full sample-data-blocks only */ 1344 debug_sprintf_event(sfdbg, 6, "%s: sdbt %#lx/%#lx " 1345 "overflow %llu timestamp %#llx\n", 1346 __func__, sdb, (unsigned long)sdbt, 1347 te->header.overflow, 1348 (te->header.f) ? trailer_timestamp(te) : 0ULL); 1349 1350 /* Collect all samples from a single sample-data-block and 1351 * flag if an (perf) event overflow happened. If so, the PMU 1352 * is stopped and remaining samples will be discarded. 1353 */ 1354 hw_collect_samples(event, (unsigned long *)sdb, &event_overflow); 1355 num_sdb++; 1356 1357 /* Reset trailer (using compare-double-and-swap) */ 1358 prev.val = READ_ONCE_ALIGNED_128(te->header.val); 1359 do { 1360 old.val = prev.val; 1361 new.val = prev.val; 1362 new.f = 0; 1363 new.a = 1; 1364 new.overflow = 0; 1365 prev.val = __cdsg(&te->header.val, old.val, new.val); 1366 } while (prev.val != old.val); 1367 1368 /* Advance to next sample-data-block */ 1369 sdbt++; 1370 if (is_link_entry(sdbt)) 1371 sdbt = get_next_sdbt(sdbt); 1372 1373 /* Update event hardware registers */ 1374 TEAR_REG(hwc) = (unsigned long) sdbt; 1375 1376 /* Stop processing sample-data if all samples of the current 1377 * sample-data-block were flushed even if it was not full. 1378 */ 1379 if (flush_all && done) 1380 break; 1381 } 1382 1383 /* Account sample overflows in the event hardware structure */ 1384 if (sampl_overflow) 1385 OVERFLOW_REG(hwc) = DIV_ROUND_UP(OVERFLOW_REG(hwc) + 1386 sampl_overflow, 1 + num_sdb); 1387 1388 /* Perf_event_overflow() and perf_event_account_interrupt() limit 1389 * the interrupt rate to an upper limit. Roughly 1000 samples per 1390 * task tick. 1391 * Hitting this limit results in a large number 1392 * of throttled REF_REPORT_THROTTLE entries and the samples 1393 * are dropped. 1394 * Slightly increase the interval to avoid hitting this limit. 1395 */ 1396 if (event_overflow) { 1397 SAMPL_RATE(hwc) += DIV_ROUND_UP(SAMPL_RATE(hwc), 10); 1398 debug_sprintf_event(sfdbg, 1, "%s: rate adjustment %ld\n", 1399 __func__, 1400 DIV_ROUND_UP(SAMPL_RATE(hwc), 10)); 1401 } 1402 1403 if (sampl_overflow || event_overflow) 1404 debug_sprintf_event(sfdbg, 4, "%s: " 1405 "overflows: sample %llu event %llu" 1406 " total %llu num_sdb %llu\n", 1407 __func__, sampl_overflow, event_overflow, 1408 OVERFLOW_REG(hwc), num_sdb); 1409 } 1410 1411 static inline unsigned long aux_sdb_index(struct aux_buffer *aux, 1412 unsigned long i) 1413 { 1414 return i % aux->sfb.num_sdb; 1415 } 1416 1417 static inline unsigned long aux_sdb_num(unsigned long start, unsigned long end) 1418 { 1419 return end >= start ? end - start + 1 : 0; 1420 } 1421 1422 static inline unsigned long aux_sdb_num_alert(struct aux_buffer *aux) 1423 { 1424 return aux_sdb_num(aux->head, aux->alert_mark); 1425 } 1426 1427 static inline unsigned long aux_sdb_num_empty(struct aux_buffer *aux) 1428 { 1429 return aux_sdb_num(aux->head, aux->empty_mark); 1430 } 1431 1432 /* 1433 * Get trailer entry by index of SDB. 1434 */ 1435 static struct hws_trailer_entry *aux_sdb_trailer(struct aux_buffer *aux, 1436 unsigned long index) 1437 { 1438 unsigned long sdb; 1439 1440 index = aux_sdb_index(aux, index); 1441 sdb = aux->sdb_index[index]; 1442 return trailer_entry_ptr(sdb); 1443 } 1444 1445 /* 1446 * Finish sampling on the cpu. Called by cpumsf_pmu_del() with pmu 1447 * disabled. Collect the full SDBs in AUX buffer which have not reached 1448 * the point of alert indicator. And ignore the SDBs which are not 1449 * full. 1450 * 1451 * 1. Scan SDBs to see how much data is there and consume them. 1452 * 2. Remove alert indicator in the buffer. 1453 */ 1454 static void aux_output_end(struct perf_output_handle *handle) 1455 { 1456 unsigned long i, range_scan, idx; 1457 struct aux_buffer *aux; 1458 struct hws_trailer_entry *te; 1459 1460 aux = perf_get_aux(handle); 1461 if (!aux) 1462 return; 1463 1464 range_scan = aux_sdb_num_alert(aux); 1465 for (i = 0, idx = aux->head; i < range_scan; i++, idx++) { 1466 te = aux_sdb_trailer(aux, idx); 1467 if (!te->header.f) 1468 break; 1469 } 1470 /* i is num of SDBs which are full */ 1471 perf_aux_output_end(handle, i << PAGE_SHIFT); 1472 1473 /* Remove alert indicators in the buffer */ 1474 te = aux_sdb_trailer(aux, aux->alert_mark); 1475 te->header.a = 0; 1476 1477 debug_sprintf_event(sfdbg, 6, "%s: SDBs %ld range %ld head %ld\n", 1478 __func__, i, range_scan, aux->head); 1479 } 1480 1481 /* 1482 * Start sampling on the CPU. Called by cpumsf_pmu_add() when an event 1483 * is first added to the CPU or rescheduled again to the CPU. It is called 1484 * with pmu disabled. 1485 * 1486 * 1. Reset the trailer of SDBs to get ready for new data. 1487 * 2. Tell the hardware where to put the data by reset the SDBs buffer 1488 * head(tear/dear). 1489 */ 1490 static int aux_output_begin(struct perf_output_handle *handle, 1491 struct aux_buffer *aux, 1492 struct cpu_hw_sf *cpuhw) 1493 { 1494 unsigned long range, i, range_scan, idx, head, base, offset; 1495 struct hws_trailer_entry *te; 1496 1497 if (WARN_ON_ONCE(handle->head & ~PAGE_MASK)) 1498 return -EINVAL; 1499 1500 aux->head = handle->head >> PAGE_SHIFT; 1501 range = (handle->size + 1) >> PAGE_SHIFT; 1502 if (range <= 1) 1503 return -ENOMEM; 1504 1505 /* 1506 * SDBs between aux->head and aux->empty_mark are already ready 1507 * for new data. range_scan is num of SDBs not within them. 1508 */ 1509 debug_sprintf_event(sfdbg, 6, 1510 "%s: range %ld head %ld alert %ld empty %ld\n", 1511 __func__, range, aux->head, aux->alert_mark, 1512 aux->empty_mark); 1513 if (range > aux_sdb_num_empty(aux)) { 1514 range_scan = range - aux_sdb_num_empty(aux); 1515 idx = aux->empty_mark + 1; 1516 for (i = 0; i < range_scan; i++, idx++) { 1517 te = aux_sdb_trailer(aux, idx); 1518 te->header.f = 0; 1519 te->header.a = 0; 1520 te->header.overflow = 0; 1521 } 1522 /* Save the position of empty SDBs */ 1523 aux->empty_mark = aux->head + range - 1; 1524 } 1525 1526 /* Set alert indicator */ 1527 aux->alert_mark = aux->head + range/2 - 1; 1528 te = aux_sdb_trailer(aux, aux->alert_mark); 1529 te->header.a = 1; 1530 1531 /* Reset hardware buffer head */ 1532 head = aux_sdb_index(aux, aux->head); 1533 base = aux->sdbt_index[head / CPUM_SF_SDB_PER_TABLE]; 1534 offset = head % CPUM_SF_SDB_PER_TABLE; 1535 cpuhw->lsctl.tear = virt_to_phys((void *)base) + offset * sizeof(unsigned long); 1536 cpuhw->lsctl.dear = virt_to_phys((void *)aux->sdb_index[head]); 1537 1538 debug_sprintf_event(sfdbg, 6, "%s: head %ld alert %ld empty %ld " 1539 "index %ld tear %#lx dear %#lx\n", __func__, 1540 aux->head, aux->alert_mark, aux->empty_mark, 1541 head / CPUM_SF_SDB_PER_TABLE, 1542 cpuhw->lsctl.tear, cpuhw->lsctl.dear); 1543 1544 return 0; 1545 } 1546 1547 /* 1548 * Set alert indicator on SDB at index @alert_index while sampler is running. 1549 * 1550 * Return true if successfully. 1551 * Return false if full indicator is already set by hardware sampler. 1552 */ 1553 static bool aux_set_alert(struct aux_buffer *aux, unsigned long alert_index, 1554 unsigned long long *overflow) 1555 { 1556 union hws_trailer_header old, prev, new; 1557 struct hws_trailer_entry *te; 1558 1559 te = aux_sdb_trailer(aux, alert_index); 1560 prev.val = READ_ONCE_ALIGNED_128(te->header.val); 1561 do { 1562 old.val = prev.val; 1563 new.val = prev.val; 1564 *overflow = old.overflow; 1565 if (old.f) { 1566 /* 1567 * SDB is already set by hardware. 1568 * Abort and try to set somewhere 1569 * behind. 1570 */ 1571 return false; 1572 } 1573 new.a = 1; 1574 new.overflow = 0; 1575 prev.val = __cdsg(&te->header.val, old.val, new.val); 1576 } while (prev.val != old.val); 1577 return true; 1578 } 1579 1580 /* 1581 * aux_reset_buffer() - Scan and setup SDBs for new samples 1582 * @aux: The AUX buffer to set 1583 * @range: The range of SDBs to scan started from aux->head 1584 * @overflow: Set to overflow count 1585 * 1586 * Set alert indicator on the SDB at index of aux->alert_mark. If this SDB is 1587 * marked as empty, check if it is already set full by the hardware sampler. 1588 * If yes, that means new data is already there before we can set an alert 1589 * indicator. Caller should try to set alert indicator to some position behind. 1590 * 1591 * Scan the SDBs in AUX buffer from behind aux->empty_mark. They are used 1592 * previously and have already been consumed by user space. Reset these SDBs 1593 * (clear full indicator and alert indicator) for new data. 1594 * If aux->alert_mark fall in this area, just set it. Overflow count is 1595 * recorded while scanning. 1596 * 1597 * SDBs between aux->head and aux->empty_mark are already reset at last time. 1598 * and ready for new samples. So scanning on this area could be skipped. 1599 * 1600 * Return true if alert indicator is set successfully and false if not. 1601 */ 1602 static bool aux_reset_buffer(struct aux_buffer *aux, unsigned long range, 1603 unsigned long long *overflow) 1604 { 1605 unsigned long i, range_scan, idx, idx_old; 1606 union hws_trailer_header old, prev, new; 1607 unsigned long long orig_overflow; 1608 struct hws_trailer_entry *te; 1609 1610 debug_sprintf_event(sfdbg, 6, "%s: range %ld head %ld alert %ld " 1611 "empty %ld\n", __func__, range, aux->head, 1612 aux->alert_mark, aux->empty_mark); 1613 if (range <= aux_sdb_num_empty(aux)) 1614 /* 1615 * No need to scan. All SDBs in range are marked as empty. 1616 * Just set alert indicator. Should check race with hardware 1617 * sampler. 1618 */ 1619 return aux_set_alert(aux, aux->alert_mark, overflow); 1620 1621 if (aux->alert_mark <= aux->empty_mark) 1622 /* 1623 * Set alert indicator on empty SDB. Should check race 1624 * with hardware sampler. 1625 */ 1626 if (!aux_set_alert(aux, aux->alert_mark, overflow)) 1627 return false; 1628 1629 /* 1630 * Scan the SDBs to clear full and alert indicator used previously. 1631 * Start scanning from one SDB behind empty_mark. If the new alert 1632 * indicator fall into this range, set it. 1633 */ 1634 range_scan = range - aux_sdb_num_empty(aux); 1635 idx_old = idx = aux->empty_mark + 1; 1636 for (i = 0; i < range_scan; i++, idx++) { 1637 te = aux_sdb_trailer(aux, idx); 1638 prev.val = READ_ONCE_ALIGNED_128(te->header.val); 1639 do { 1640 old.val = prev.val; 1641 new.val = prev.val; 1642 orig_overflow = old.overflow; 1643 new.f = 0; 1644 new.overflow = 0; 1645 if (idx == aux->alert_mark) 1646 new.a = 1; 1647 else 1648 new.a = 0; 1649 prev.val = __cdsg(&te->header.val, old.val, new.val); 1650 } while (prev.val != old.val); 1651 *overflow += orig_overflow; 1652 } 1653 1654 /* Update empty_mark to new position */ 1655 aux->empty_mark = aux->head + range - 1; 1656 1657 debug_sprintf_event(sfdbg, 6, "%s: range_scan %ld idx %ld..%ld " 1658 "empty %ld\n", __func__, range_scan, idx_old, 1659 idx - 1, aux->empty_mark); 1660 return true; 1661 } 1662 1663 /* 1664 * Measurement alert handler for diagnostic mode sampling. 1665 */ 1666 static void hw_collect_aux(struct cpu_hw_sf *cpuhw) 1667 { 1668 struct aux_buffer *aux; 1669 int done = 0; 1670 unsigned long range = 0, size; 1671 unsigned long long overflow = 0; 1672 struct perf_output_handle *handle = &cpuhw->handle; 1673 unsigned long num_sdb; 1674 1675 aux = perf_get_aux(handle); 1676 if (WARN_ON_ONCE(!aux)) 1677 return; 1678 1679 /* Inform user space new data arrived */ 1680 size = aux_sdb_num_alert(aux) << PAGE_SHIFT; 1681 debug_sprintf_event(sfdbg, 6, "%s: #alert %ld\n", __func__, 1682 size >> PAGE_SHIFT); 1683 perf_aux_output_end(handle, size); 1684 1685 num_sdb = aux->sfb.num_sdb; 1686 while (!done) { 1687 /* Get an output handle */ 1688 aux = perf_aux_output_begin(handle, cpuhw->event); 1689 if (handle->size == 0) { 1690 pr_err("The AUX buffer with %lu pages for the " 1691 "diagnostic-sampling mode is full\n", 1692 num_sdb); 1693 debug_sprintf_event(sfdbg, 1, 1694 "%s: AUX buffer used up\n", 1695 __func__); 1696 break; 1697 } 1698 if (WARN_ON_ONCE(!aux)) 1699 return; 1700 1701 /* Update head and alert_mark to new position */ 1702 aux->head = handle->head >> PAGE_SHIFT; 1703 range = (handle->size + 1) >> PAGE_SHIFT; 1704 if (range == 1) 1705 aux->alert_mark = aux->head; 1706 else 1707 aux->alert_mark = aux->head + range/2 - 1; 1708 1709 if (aux_reset_buffer(aux, range, &overflow)) { 1710 if (!overflow) { 1711 done = 1; 1712 break; 1713 } 1714 size = range << PAGE_SHIFT; 1715 perf_aux_output_end(&cpuhw->handle, size); 1716 pr_err("Sample data caused the AUX buffer with %lu " 1717 "pages to overflow\n", aux->sfb.num_sdb); 1718 debug_sprintf_event(sfdbg, 1, "%s: head %ld range %ld " 1719 "overflow %lld\n", __func__, 1720 aux->head, range, overflow); 1721 } else { 1722 size = aux_sdb_num_alert(aux) << PAGE_SHIFT; 1723 perf_aux_output_end(&cpuhw->handle, size); 1724 debug_sprintf_event(sfdbg, 6, "%s: head %ld alert %ld " 1725 "already full, try another\n", 1726 __func__, 1727 aux->head, aux->alert_mark); 1728 } 1729 } 1730 1731 if (done) 1732 debug_sprintf_event(sfdbg, 6, "%s: head %ld alert %ld " 1733 "empty %ld\n", __func__, aux->head, 1734 aux->alert_mark, aux->empty_mark); 1735 } 1736 1737 /* 1738 * Callback when freeing AUX buffers. 1739 */ 1740 static void aux_buffer_free(void *data) 1741 { 1742 struct aux_buffer *aux = data; 1743 unsigned long i, num_sdbt; 1744 1745 if (!aux) 1746 return; 1747 1748 /* Free SDBT. SDB is freed by the caller */ 1749 num_sdbt = aux->sfb.num_sdbt; 1750 for (i = 0; i < num_sdbt; i++) 1751 free_page(aux->sdbt_index[i]); 1752 1753 kfree(aux->sdbt_index); 1754 kfree(aux->sdb_index); 1755 kfree(aux); 1756 1757 debug_sprintf_event(sfdbg, 4, "%s: SDBTs %lu\n", __func__, num_sdbt); 1758 } 1759 1760 static void aux_sdb_init(unsigned long sdb) 1761 { 1762 struct hws_trailer_entry *te; 1763 1764 te = trailer_entry_ptr(sdb); 1765 1766 /* Save clock base */ 1767 te->clock_base = 1; 1768 te->progusage2 = tod_clock_base.tod; 1769 } 1770 1771 /* 1772 * aux_buffer_setup() - Setup AUX buffer for diagnostic mode sampling 1773 * @event: Event the buffer is setup for, event->cpu == -1 means current 1774 * @pages: Array of pointers to buffer pages passed from perf core 1775 * @nr_pages: Total pages 1776 * @snapshot: Flag for snapshot mode 1777 * 1778 * This is the callback when setup an event using AUX buffer. Perf tool can 1779 * trigger this by an additional mmap() call on the event. Unlike the buffer 1780 * for basic samples, AUX buffer belongs to the event. It is scheduled with 1781 * the task among online cpus when it is a per-thread event. 1782 * 1783 * Return the private AUX buffer structure if success or NULL if fails. 1784 */ 1785 static void *aux_buffer_setup(struct perf_event *event, void **pages, 1786 int nr_pages, bool snapshot) 1787 { 1788 struct sf_buffer *sfb; 1789 struct aux_buffer *aux; 1790 unsigned long *new, *tail; 1791 int i, n_sdbt; 1792 1793 if (!nr_pages || !pages) 1794 return NULL; 1795 1796 if (nr_pages > CPUM_SF_MAX_SDB * CPUM_SF_SDB_DIAG_FACTOR) { 1797 pr_err("AUX buffer size (%i pages) is larger than the " 1798 "maximum sampling buffer limit\n", 1799 nr_pages); 1800 return NULL; 1801 } else if (nr_pages < CPUM_SF_MIN_SDB * CPUM_SF_SDB_DIAG_FACTOR) { 1802 pr_err("AUX buffer size (%i pages) is less than the " 1803 "minimum sampling buffer limit\n", 1804 nr_pages); 1805 return NULL; 1806 } 1807 1808 /* Allocate aux_buffer struct for the event */ 1809 aux = kzalloc(sizeof(struct aux_buffer), GFP_KERNEL); 1810 if (!aux) 1811 goto no_aux; 1812 sfb = &aux->sfb; 1813 1814 /* Allocate sdbt_index for fast reference */ 1815 n_sdbt = DIV_ROUND_UP(nr_pages, CPUM_SF_SDB_PER_TABLE); 1816 aux->sdbt_index = kmalloc_array(n_sdbt, sizeof(void *), GFP_KERNEL); 1817 if (!aux->sdbt_index) 1818 goto no_sdbt_index; 1819 1820 /* Allocate sdb_index for fast reference */ 1821 aux->sdb_index = kmalloc_array(nr_pages, sizeof(void *), GFP_KERNEL); 1822 if (!aux->sdb_index) 1823 goto no_sdb_index; 1824 1825 /* Allocate the first SDBT */ 1826 sfb->num_sdbt = 0; 1827 sfb->sdbt = (unsigned long *) get_zeroed_page(GFP_KERNEL); 1828 if (!sfb->sdbt) 1829 goto no_sdbt; 1830 aux->sdbt_index[sfb->num_sdbt++] = (unsigned long)sfb->sdbt; 1831 tail = sfb->tail = sfb->sdbt; 1832 1833 /* 1834 * Link the provided pages of AUX buffer to SDBT. 1835 * Allocate SDBT if needed. 1836 */ 1837 for (i = 0; i < nr_pages; i++, tail++) { 1838 if (require_table_link(tail)) { 1839 new = (unsigned long *) get_zeroed_page(GFP_KERNEL); 1840 if (!new) 1841 goto no_sdbt; 1842 aux->sdbt_index[sfb->num_sdbt++] = (unsigned long)new; 1843 /* Link current page to tail of chain */ 1844 *tail = virt_to_phys(new) + 1; 1845 tail = new; 1846 } 1847 /* Tail is the entry in a SDBT */ 1848 *tail = virt_to_phys(pages[i]); 1849 aux->sdb_index[i] = (unsigned long)pages[i]; 1850 aux_sdb_init((unsigned long)pages[i]); 1851 } 1852 sfb->num_sdb = nr_pages; 1853 1854 /* Link the last entry in the SDBT to the first SDBT */ 1855 *tail = virt_to_phys(sfb->sdbt) + 1; 1856 sfb->tail = tail; 1857 1858 /* 1859 * Initial all SDBs are zeroed. Mark it as empty. 1860 * So there is no need to clear the full indicator 1861 * when this event is first added. 1862 */ 1863 aux->empty_mark = sfb->num_sdb - 1; 1864 1865 debug_sprintf_event(sfdbg, 4, "%s: SDBTs %lu SDBs %lu\n", __func__, 1866 sfb->num_sdbt, sfb->num_sdb); 1867 1868 return aux; 1869 1870 no_sdbt: 1871 /* SDBs (AUX buffer pages) are freed by caller */ 1872 for (i = 0; i < sfb->num_sdbt; i++) 1873 free_page(aux->sdbt_index[i]); 1874 kfree(aux->sdb_index); 1875 no_sdb_index: 1876 kfree(aux->sdbt_index); 1877 no_sdbt_index: 1878 kfree(aux); 1879 no_aux: 1880 return NULL; 1881 } 1882 1883 static void cpumsf_pmu_read(struct perf_event *event) 1884 { 1885 /* Nothing to do ... updates are interrupt-driven */ 1886 } 1887 1888 /* Check if the new sampling period/freqeuncy is appropriate. 1889 * 1890 * Return non-zero on error and zero on passed checks. 1891 */ 1892 static int cpumsf_pmu_check_period(struct perf_event *event, u64 value) 1893 { 1894 struct hws_qsi_info_block si; 1895 unsigned long rate; 1896 bool do_freq; 1897 1898 memset(&si, 0, sizeof(si)); 1899 if (event->cpu == -1) { 1900 if (qsi(&si)) 1901 return -ENODEV; 1902 } else { 1903 /* Event is pinned to a particular CPU, retrieve the per-CPU 1904 * sampling structure for accessing the CPU-specific QSI. 1905 */ 1906 struct cpu_hw_sf *cpuhw = &per_cpu(cpu_hw_sf, event->cpu); 1907 1908 si = cpuhw->qsi; 1909 } 1910 1911 do_freq = !!SAMPLE_FREQ_MODE(&event->hw); 1912 rate = getrate(do_freq, value, &si); 1913 if (!rate) 1914 return -EINVAL; 1915 1916 event->attr.sample_period = rate; 1917 SAMPL_RATE(&event->hw) = rate; 1918 hw_init_period(&event->hw, SAMPL_RATE(&event->hw)); 1919 debug_sprintf_event(sfdbg, 4, "%s:" 1920 " cpu %d value %#llx period %#llx freq %d\n", 1921 __func__, event->cpu, value, 1922 event->attr.sample_period, do_freq); 1923 return 0; 1924 } 1925 1926 /* Activate sampling control. 1927 * Next call of pmu_enable() starts sampling. 1928 */ 1929 static void cpumsf_pmu_start(struct perf_event *event, int flags) 1930 { 1931 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 1932 1933 if (WARN_ON_ONCE(!(event->hw.state & PERF_HES_STOPPED))) 1934 return; 1935 1936 if (flags & PERF_EF_RELOAD) 1937 WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE)); 1938 1939 perf_pmu_disable(event->pmu); 1940 event->hw.state = 0; 1941 cpuhw->lsctl.cs = 1; 1942 if (SAMPL_DIAG_MODE(&event->hw)) 1943 cpuhw->lsctl.cd = 1; 1944 perf_pmu_enable(event->pmu); 1945 } 1946 1947 /* Deactivate sampling control. 1948 * Next call of pmu_enable() stops sampling. 1949 */ 1950 static void cpumsf_pmu_stop(struct perf_event *event, int flags) 1951 { 1952 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 1953 1954 if (event->hw.state & PERF_HES_STOPPED) 1955 return; 1956 1957 perf_pmu_disable(event->pmu); 1958 cpuhw->lsctl.cs = 0; 1959 cpuhw->lsctl.cd = 0; 1960 event->hw.state |= PERF_HES_STOPPED; 1961 1962 if ((flags & PERF_EF_UPDATE) && !(event->hw.state & PERF_HES_UPTODATE)) { 1963 hw_perf_event_update(event, 1); 1964 event->hw.state |= PERF_HES_UPTODATE; 1965 } 1966 perf_pmu_enable(event->pmu); 1967 } 1968 1969 static int cpumsf_pmu_add(struct perf_event *event, int flags) 1970 { 1971 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 1972 struct aux_buffer *aux; 1973 int err; 1974 1975 if (cpuhw->flags & PMU_F_IN_USE) 1976 return -EAGAIN; 1977 1978 if (!SAMPL_DIAG_MODE(&event->hw) && !cpuhw->sfb.sdbt) 1979 return -EINVAL; 1980 1981 err = 0; 1982 perf_pmu_disable(event->pmu); 1983 1984 event->hw.state = PERF_HES_UPTODATE | PERF_HES_STOPPED; 1985 1986 /* Set up sampling controls. Always program the sampling register 1987 * using the SDB-table start. Reset TEAR_REG event hardware register 1988 * that is used by hw_perf_event_update() to store the sampling buffer 1989 * position after samples have been flushed. 1990 */ 1991 cpuhw->lsctl.s = 0; 1992 cpuhw->lsctl.h = 1; 1993 cpuhw->lsctl.interval = SAMPL_RATE(&event->hw); 1994 if (!SAMPL_DIAG_MODE(&event->hw)) { 1995 cpuhw->lsctl.tear = virt_to_phys(cpuhw->sfb.sdbt); 1996 cpuhw->lsctl.dear = *(unsigned long *) cpuhw->sfb.sdbt; 1997 TEAR_REG(&event->hw) = (unsigned long) cpuhw->sfb.sdbt; 1998 } 1999 2000 /* Ensure sampling functions are in the disabled state. If disabled, 2001 * switch on sampling enable control. */ 2002 if (WARN_ON_ONCE(cpuhw->lsctl.es == 1 || cpuhw->lsctl.ed == 1)) { 2003 err = -EAGAIN; 2004 goto out; 2005 } 2006 if (SAMPL_DIAG_MODE(&event->hw)) { 2007 aux = perf_aux_output_begin(&cpuhw->handle, event); 2008 if (!aux) { 2009 err = -EINVAL; 2010 goto out; 2011 } 2012 err = aux_output_begin(&cpuhw->handle, aux, cpuhw); 2013 if (err) 2014 goto out; 2015 cpuhw->lsctl.ed = 1; 2016 } 2017 cpuhw->lsctl.es = 1; 2018 2019 /* Set in_use flag and store event */ 2020 cpuhw->event = event; 2021 cpuhw->flags |= PMU_F_IN_USE; 2022 2023 if (flags & PERF_EF_START) 2024 cpumsf_pmu_start(event, PERF_EF_RELOAD); 2025 out: 2026 perf_event_update_userpage(event); 2027 perf_pmu_enable(event->pmu); 2028 return err; 2029 } 2030 2031 static void cpumsf_pmu_del(struct perf_event *event, int flags) 2032 { 2033 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 2034 2035 perf_pmu_disable(event->pmu); 2036 cpumsf_pmu_stop(event, PERF_EF_UPDATE); 2037 2038 cpuhw->lsctl.es = 0; 2039 cpuhw->lsctl.ed = 0; 2040 cpuhw->flags &= ~PMU_F_IN_USE; 2041 cpuhw->event = NULL; 2042 2043 if (SAMPL_DIAG_MODE(&event->hw)) 2044 aux_output_end(&cpuhw->handle); 2045 perf_event_update_userpage(event); 2046 perf_pmu_enable(event->pmu); 2047 } 2048 2049 CPUMF_EVENT_ATTR(SF, SF_CYCLES_BASIC, PERF_EVENT_CPUM_SF); 2050 CPUMF_EVENT_ATTR(SF, SF_CYCLES_BASIC_DIAG, PERF_EVENT_CPUM_SF_DIAG); 2051 2052 /* Attribute list for CPU_SF. 2053 * 2054 * The availablitiy depends on the CPU_MF sampling facility authorization 2055 * for basic + diagnositic samples. This is determined at initialization 2056 * time by the sampling facility device driver. 2057 * If the authorization for basic samples is turned off, it should be 2058 * also turned off for diagnostic sampling. 2059 * 2060 * During initialization of the device driver, check the authorization 2061 * level for diagnostic sampling and installs the attribute 2062 * file for diagnostic sampling if necessary. 2063 * 2064 * For now install a placeholder to reference all possible attributes: 2065 * SF_CYCLES_BASIC and SF_CYCLES_BASIC_DIAG. 2066 * Add another entry for the final NULL pointer. 2067 */ 2068 enum { 2069 SF_CYCLES_BASIC_ATTR_IDX = 0, 2070 SF_CYCLES_BASIC_DIAG_ATTR_IDX, 2071 SF_CYCLES_ATTR_MAX 2072 }; 2073 2074 static struct attribute *cpumsf_pmu_events_attr[SF_CYCLES_ATTR_MAX + 1] = { 2075 [SF_CYCLES_BASIC_ATTR_IDX] = CPUMF_EVENT_PTR(SF, SF_CYCLES_BASIC) 2076 }; 2077 2078 PMU_FORMAT_ATTR(event, "config:0-63"); 2079 2080 static struct attribute *cpumsf_pmu_format_attr[] = { 2081 &format_attr_event.attr, 2082 NULL, 2083 }; 2084 2085 static struct attribute_group cpumsf_pmu_events_group = { 2086 .name = "events", 2087 .attrs = cpumsf_pmu_events_attr, 2088 }; 2089 2090 static struct attribute_group cpumsf_pmu_format_group = { 2091 .name = "format", 2092 .attrs = cpumsf_pmu_format_attr, 2093 }; 2094 2095 static const struct attribute_group *cpumsf_pmu_attr_groups[] = { 2096 &cpumsf_pmu_events_group, 2097 &cpumsf_pmu_format_group, 2098 NULL, 2099 }; 2100 2101 static struct pmu cpumf_sampling = { 2102 .pmu_enable = cpumsf_pmu_enable, 2103 .pmu_disable = cpumsf_pmu_disable, 2104 2105 .event_init = cpumsf_pmu_event_init, 2106 .add = cpumsf_pmu_add, 2107 .del = cpumsf_pmu_del, 2108 2109 .start = cpumsf_pmu_start, 2110 .stop = cpumsf_pmu_stop, 2111 .read = cpumsf_pmu_read, 2112 2113 .attr_groups = cpumsf_pmu_attr_groups, 2114 2115 .setup_aux = aux_buffer_setup, 2116 .free_aux = aux_buffer_free, 2117 2118 .check_period = cpumsf_pmu_check_period, 2119 }; 2120 2121 static void cpumf_measurement_alert(struct ext_code ext_code, 2122 unsigned int alert, unsigned long unused) 2123 { 2124 struct cpu_hw_sf *cpuhw; 2125 2126 if (!(alert & CPU_MF_INT_SF_MASK)) 2127 return; 2128 inc_irq_stat(IRQEXT_CMS); 2129 cpuhw = this_cpu_ptr(&cpu_hw_sf); 2130 2131 /* Measurement alerts are shared and might happen when the PMU 2132 * is not reserved. Ignore these alerts in this case. */ 2133 if (!(cpuhw->flags & PMU_F_RESERVED)) 2134 return; 2135 2136 /* The processing below must take care of multiple alert events that 2137 * might be indicated concurrently. */ 2138 2139 /* Program alert request */ 2140 if (alert & CPU_MF_INT_SF_PRA) { 2141 if (cpuhw->flags & PMU_F_IN_USE) 2142 if (SAMPL_DIAG_MODE(&cpuhw->event->hw)) 2143 hw_collect_aux(cpuhw); 2144 else 2145 hw_perf_event_update(cpuhw->event, 0); 2146 else 2147 WARN_ON_ONCE(!(cpuhw->flags & PMU_F_IN_USE)); 2148 } 2149 2150 /* Report measurement alerts only for non-PRA codes */ 2151 if (alert != CPU_MF_INT_SF_PRA) 2152 debug_sprintf_event(sfdbg, 6, "%s: alert %#x\n", __func__, 2153 alert); 2154 2155 /* Sampling authorization change request */ 2156 if (alert & CPU_MF_INT_SF_SACA) 2157 qsi(&cpuhw->qsi); 2158 2159 /* Loss of sample data due to high-priority machine activities */ 2160 if (alert & CPU_MF_INT_SF_LSDA) { 2161 pr_err("Sample data was lost\n"); 2162 cpuhw->flags |= PMU_F_ERR_LSDA; 2163 sf_disable(); 2164 } 2165 2166 /* Invalid sampling buffer entry */ 2167 if (alert & (CPU_MF_INT_SF_IAE|CPU_MF_INT_SF_ISE)) { 2168 pr_err("A sampling buffer entry is incorrect (alert=0x%x)\n", 2169 alert); 2170 cpuhw->flags |= PMU_F_ERR_IBE; 2171 sf_disable(); 2172 } 2173 } 2174 2175 static int cpusf_pmu_setup(unsigned int cpu, int flags) 2176 { 2177 /* Ignore the notification if no events are scheduled on the PMU. 2178 * This might be racy... 2179 */ 2180 if (!atomic_read(&num_events)) 2181 return 0; 2182 2183 local_irq_disable(); 2184 setup_pmc_cpu(&flags); 2185 local_irq_enable(); 2186 return 0; 2187 } 2188 2189 static int s390_pmu_sf_online_cpu(unsigned int cpu) 2190 { 2191 return cpusf_pmu_setup(cpu, PMC_INIT); 2192 } 2193 2194 static int s390_pmu_sf_offline_cpu(unsigned int cpu) 2195 { 2196 return cpusf_pmu_setup(cpu, PMC_RELEASE); 2197 } 2198 2199 static int param_get_sfb_size(char *buffer, const struct kernel_param *kp) 2200 { 2201 if (!cpum_sf_avail()) 2202 return -ENODEV; 2203 return sprintf(buffer, "%lu,%lu", CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB); 2204 } 2205 2206 static int param_set_sfb_size(const char *val, const struct kernel_param *kp) 2207 { 2208 int rc; 2209 unsigned long min, max; 2210 2211 if (!cpum_sf_avail()) 2212 return -ENODEV; 2213 if (!val || !strlen(val)) 2214 return -EINVAL; 2215 2216 /* Valid parameter values: "min,max" or "max" */ 2217 min = CPUM_SF_MIN_SDB; 2218 max = CPUM_SF_MAX_SDB; 2219 if (strchr(val, ',')) 2220 rc = (sscanf(val, "%lu,%lu", &min, &max) == 2) ? 0 : -EINVAL; 2221 else 2222 rc = kstrtoul(val, 10, &max); 2223 2224 if (min < 2 || min >= max || max > get_num_physpages()) 2225 rc = -EINVAL; 2226 if (rc) 2227 return rc; 2228 2229 sfb_set_limits(min, max); 2230 pr_info("The sampling buffer limits have changed to: " 2231 "min %lu max %lu (diag %lu)\n", 2232 CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB, CPUM_SF_SDB_DIAG_FACTOR); 2233 return 0; 2234 } 2235 2236 #define param_check_sfb_size(name, p) __param_check(name, p, void) 2237 static const struct kernel_param_ops param_ops_sfb_size = { 2238 .set = param_set_sfb_size, 2239 .get = param_get_sfb_size, 2240 }; 2241 2242 #define RS_INIT_FAILURE_QSI 0x0001 2243 #define RS_INIT_FAILURE_BSDES 0x0002 2244 #define RS_INIT_FAILURE_ALRT 0x0003 2245 #define RS_INIT_FAILURE_PERF 0x0004 2246 static void __init pr_cpumsf_err(unsigned int reason) 2247 { 2248 pr_err("Sampling facility support for perf is not available: " 2249 "reason %#x\n", reason); 2250 } 2251 2252 static int __init init_cpum_sampling_pmu(void) 2253 { 2254 struct hws_qsi_info_block si; 2255 int err; 2256 2257 if (!cpum_sf_avail()) 2258 return -ENODEV; 2259 2260 memset(&si, 0, sizeof(si)); 2261 if (qsi(&si)) { 2262 pr_cpumsf_err(RS_INIT_FAILURE_QSI); 2263 return -ENODEV; 2264 } 2265 2266 if (!si.as && !si.ad) 2267 return -ENODEV; 2268 2269 if (si.bsdes != sizeof(struct hws_basic_entry)) { 2270 pr_cpumsf_err(RS_INIT_FAILURE_BSDES); 2271 return -EINVAL; 2272 } 2273 2274 if (si.ad) { 2275 sfb_set_limits(CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB); 2276 /* Sampling of diagnostic data authorized, 2277 * install event into attribute list of PMU device. 2278 */ 2279 cpumsf_pmu_events_attr[SF_CYCLES_BASIC_DIAG_ATTR_IDX] = 2280 CPUMF_EVENT_PTR(SF, SF_CYCLES_BASIC_DIAG); 2281 } 2282 2283 sfdbg = debug_register(KMSG_COMPONENT, 2, 1, 80); 2284 if (!sfdbg) { 2285 pr_err("Registering for s390dbf failed\n"); 2286 return -ENOMEM; 2287 } 2288 debug_register_view(sfdbg, &debug_sprintf_view); 2289 2290 err = register_external_irq(EXT_IRQ_MEASURE_ALERT, 2291 cpumf_measurement_alert); 2292 if (err) { 2293 pr_cpumsf_err(RS_INIT_FAILURE_ALRT); 2294 debug_unregister(sfdbg); 2295 goto out; 2296 } 2297 2298 err = perf_pmu_register(&cpumf_sampling, "cpum_sf", PERF_TYPE_RAW); 2299 if (err) { 2300 pr_cpumsf_err(RS_INIT_FAILURE_PERF); 2301 unregister_external_irq(EXT_IRQ_MEASURE_ALERT, 2302 cpumf_measurement_alert); 2303 debug_unregister(sfdbg); 2304 goto out; 2305 } 2306 2307 cpuhp_setup_state(CPUHP_AP_PERF_S390_SF_ONLINE, "perf/s390/sf:online", 2308 s390_pmu_sf_online_cpu, s390_pmu_sf_offline_cpu); 2309 out: 2310 return err; 2311 } 2312 2313 arch_initcall(init_cpum_sampling_pmu); 2314 core_param(cpum_sfb_size, CPUM_SF_MAX_SDB, sfb_size, 0644); 2315