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 <linux/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 struct cpu_hw_sf *cpusf = this_cpu_ptr(&cpu_hw_sf); 598 int err = 0; 599 600 switch (*((int *)flags)) { 601 case PMC_INIT: 602 memset(cpusf, 0, sizeof(*cpusf)); 603 err = qsi(&cpusf->qsi); 604 if (err) 605 break; 606 cpusf->flags |= PMU_F_RESERVED; 607 err = sf_disable(); 608 break; 609 case PMC_RELEASE: 610 cpusf->flags &= ~PMU_F_RESERVED; 611 err = sf_disable(); 612 if (!err) 613 deallocate_buffers(cpusf); 614 break; 615 } 616 if (err) { 617 *((int *)flags) |= PMC_FAILURE; 618 pr_err("Switching off the sampling facility failed with rc %i\n", err); 619 } 620 } 621 622 static void release_pmc_hardware(void) 623 { 624 int flags = PMC_RELEASE; 625 626 irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT); 627 on_each_cpu(setup_pmc_cpu, &flags, 1); 628 } 629 630 static int reserve_pmc_hardware(void) 631 { 632 int flags = PMC_INIT; 633 634 on_each_cpu(setup_pmc_cpu, &flags, 1); 635 if (flags & PMC_FAILURE) { 636 release_pmc_hardware(); 637 return -ENODEV; 638 } 639 irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT); 640 641 return 0; 642 } 643 644 static void hw_perf_event_destroy(struct perf_event *event) 645 { 646 /* Release PMC if this is the last perf event */ 647 if (!atomic_add_unless(&num_events, -1, 1)) { 648 mutex_lock(&pmc_reserve_mutex); 649 if (atomic_dec_return(&num_events) == 0) 650 release_pmc_hardware(); 651 mutex_unlock(&pmc_reserve_mutex); 652 } 653 } 654 655 static void hw_init_period(struct hw_perf_event *hwc, u64 period) 656 { 657 hwc->sample_period = period; 658 hwc->last_period = hwc->sample_period; 659 local64_set(&hwc->period_left, hwc->sample_period); 660 } 661 662 static unsigned long hw_limit_rate(const struct hws_qsi_info_block *si, 663 unsigned long rate) 664 { 665 return clamp_t(unsigned long, rate, 666 si->min_sampl_rate, si->max_sampl_rate); 667 } 668 669 static u32 cpumsf_pid_type(struct perf_event *event, 670 u32 pid, enum pid_type type) 671 { 672 struct task_struct *tsk; 673 674 /* Idle process */ 675 if (!pid) 676 goto out; 677 678 tsk = find_task_by_pid_ns(pid, &init_pid_ns); 679 pid = -1; 680 if (tsk) { 681 /* 682 * Only top level events contain the pid namespace in which 683 * they are created. 684 */ 685 if (event->parent) 686 event = event->parent; 687 pid = __task_pid_nr_ns(tsk, type, event->ns); 688 /* 689 * See also 1d953111b648 690 * "perf/core: Don't report zero PIDs for exiting tasks". 691 */ 692 if (!pid && !pid_alive(tsk)) 693 pid = -1; 694 } 695 out: 696 return pid; 697 } 698 699 static void cpumsf_output_event_pid(struct perf_event *event, 700 struct perf_sample_data *data, 701 struct pt_regs *regs) 702 { 703 u32 pid; 704 struct perf_event_header header; 705 struct perf_output_handle handle; 706 707 /* 708 * Obtain the PID from the basic-sampling data entry and 709 * correct the data->tid_entry.pid value. 710 */ 711 pid = data->tid_entry.pid; 712 713 /* Protect callchain buffers, tasks */ 714 rcu_read_lock(); 715 716 perf_prepare_sample(data, event, regs); 717 perf_prepare_header(&header, data, event, regs); 718 if (perf_output_begin(&handle, data, event, header.size)) 719 goto out; 720 721 /* Update the process ID (see also kernel/events/core.c) */ 722 data->tid_entry.pid = cpumsf_pid_type(event, pid, PIDTYPE_TGID); 723 data->tid_entry.tid = cpumsf_pid_type(event, pid, PIDTYPE_PID); 724 725 perf_output_sample(&handle, &header, data, event); 726 perf_output_end(&handle); 727 out: 728 rcu_read_unlock(); 729 } 730 731 static unsigned long getrate(bool freq, unsigned long sample, 732 struct hws_qsi_info_block *si) 733 { 734 unsigned long rate; 735 736 if (freq) { 737 rate = freq_to_sample_rate(si, sample); 738 rate = hw_limit_rate(si, rate); 739 } else { 740 /* The min/max sampling rates specifies the valid range 741 * of sample periods. If the specified sample period is 742 * out of range, limit the period to the range boundary. 743 */ 744 rate = hw_limit_rate(si, sample); 745 746 /* The perf core maintains a maximum sample rate that is 747 * configurable through the sysctl interface. Ensure the 748 * sampling rate does not exceed this value. This also helps 749 * to avoid throttling when pushing samples with 750 * perf_event_overflow(). 751 */ 752 if (sample_rate_to_freq(si, rate) > 753 sysctl_perf_event_sample_rate) { 754 debug_sprintf_event(sfdbg, 1, "%s: " 755 "Sampling rate exceeds maximum " 756 "perf sample rate\n", __func__); 757 rate = 0; 758 } 759 } 760 return rate; 761 } 762 763 /* The sampling information (si) contains information about the 764 * min/max sampling intervals and the CPU speed. So calculate the 765 * correct sampling interval and avoid the whole period adjust 766 * feedback loop. 767 * 768 * Since the CPU Measurement sampling facility can not handle frequency 769 * calculate the sampling interval when frequency is specified using 770 * this formula: 771 * interval := cpu_speed * 1000000 / sample_freq 772 * 773 * Returns errno on bad input and zero on success with parameter interval 774 * set to the correct sampling rate. 775 * 776 * Note: This function turns off freq bit to avoid calling function 777 * perf_adjust_period(). This causes frequency adjustment in the common 778 * code part which causes tremendous variations in the counter values. 779 */ 780 static int __hw_perf_event_init_rate(struct perf_event *event, 781 struct hws_qsi_info_block *si) 782 { 783 struct perf_event_attr *attr = &event->attr; 784 struct hw_perf_event *hwc = &event->hw; 785 unsigned long rate; 786 787 if (attr->freq) { 788 if (!attr->sample_freq) 789 return -EINVAL; 790 rate = getrate(attr->freq, attr->sample_freq, si); 791 attr->freq = 0; /* Don't call perf_adjust_period() */ 792 SAMPL_FLAGS(hwc) |= PERF_CPUM_SF_FREQ_MODE; 793 } else { 794 rate = getrate(attr->freq, attr->sample_period, si); 795 if (!rate) 796 return -EINVAL; 797 } 798 attr->sample_period = rate; 799 SAMPL_RATE(hwc) = rate; 800 hw_init_period(hwc, SAMPL_RATE(hwc)); 801 debug_sprintf_event(sfdbg, 4, "%s: cpu %d period %#llx freq %d,%#lx\n", 802 __func__, event->cpu, event->attr.sample_period, 803 event->attr.freq, SAMPLE_FREQ_MODE(hwc)); 804 return 0; 805 } 806 807 static int __hw_perf_event_init(struct perf_event *event) 808 { 809 struct cpu_hw_sf *cpuhw; 810 struct hws_qsi_info_block si; 811 struct perf_event_attr *attr = &event->attr; 812 struct hw_perf_event *hwc = &event->hw; 813 int cpu, err; 814 815 /* Reserve CPU-measurement sampling facility */ 816 err = 0; 817 if (!atomic_inc_not_zero(&num_events)) { 818 mutex_lock(&pmc_reserve_mutex); 819 if (atomic_read(&num_events) == 0 && reserve_pmc_hardware()) 820 err = -EBUSY; 821 else 822 atomic_inc(&num_events); 823 mutex_unlock(&pmc_reserve_mutex); 824 } 825 event->destroy = hw_perf_event_destroy; 826 827 if (err) 828 goto out; 829 830 /* Access per-CPU sampling information (query sampling info) */ 831 /* 832 * The event->cpu value can be -1 to count on every CPU, for example, 833 * when attaching to a task. If this is specified, use the query 834 * sampling info from the current CPU, otherwise use event->cpu to 835 * retrieve the per-CPU information. 836 * Later, cpuhw indicates whether to allocate sampling buffers for a 837 * particular CPU (cpuhw!=NULL) or each online CPU (cpuw==NULL). 838 */ 839 memset(&si, 0, sizeof(si)); 840 cpuhw = NULL; 841 if (event->cpu == -1) 842 qsi(&si); 843 else { 844 /* Event is pinned to a particular CPU, retrieve the per-CPU 845 * sampling structure for accessing the CPU-specific QSI. 846 */ 847 cpuhw = &per_cpu(cpu_hw_sf, event->cpu); 848 si = cpuhw->qsi; 849 } 850 851 /* Check sampling facility authorization and, if not authorized, 852 * fall back to other PMUs. It is safe to check any CPU because 853 * the authorization is identical for all configured CPUs. 854 */ 855 if (!si.as) { 856 err = -ENOENT; 857 goto out; 858 } 859 860 if (si.ribm & CPU_MF_SF_RIBM_NOTAV) { 861 pr_warn("CPU Measurement Facility sampling is temporarily not available\n"); 862 err = -EBUSY; 863 goto out; 864 } 865 866 /* Always enable basic sampling */ 867 SAMPL_FLAGS(hwc) = PERF_CPUM_SF_BASIC_MODE; 868 869 /* Check if diagnostic sampling is requested. Deny if the required 870 * sampling authorization is missing. 871 */ 872 if (attr->config == PERF_EVENT_CPUM_SF_DIAG) { 873 if (!si.ad) { 874 err = -EPERM; 875 goto out; 876 } 877 SAMPL_FLAGS(hwc) |= PERF_CPUM_SF_DIAG_MODE; 878 } 879 880 err = __hw_perf_event_init_rate(event, &si); 881 if (err) 882 goto out; 883 884 /* Initialize sample data overflow accounting */ 885 hwc->extra_reg.reg = REG_OVERFLOW; 886 OVERFLOW_REG(hwc) = 0; 887 888 /* Use AUX buffer. No need to allocate it by ourself */ 889 if (attr->config == PERF_EVENT_CPUM_SF_DIAG) 890 return 0; 891 892 /* Allocate the per-CPU sampling buffer using the CPU information 893 * from the event. If the event is not pinned to a particular 894 * CPU (event->cpu == -1; or cpuhw == NULL), allocate sampling 895 * buffers for each online CPU. 896 */ 897 if (cpuhw) 898 /* Event is pinned to a particular CPU */ 899 err = allocate_buffers(cpuhw, hwc); 900 else { 901 /* Event is not pinned, allocate sampling buffer on 902 * each online CPU 903 */ 904 for_each_online_cpu(cpu) { 905 cpuhw = &per_cpu(cpu_hw_sf, cpu); 906 err = allocate_buffers(cpuhw, hwc); 907 if (err) 908 break; 909 } 910 } 911 912 /* If PID/TID sampling is active, replace the default overflow 913 * handler to extract and resolve the PIDs from the basic-sampling 914 * data entries. 915 */ 916 if (event->attr.sample_type & PERF_SAMPLE_TID) 917 if (is_default_overflow_handler(event)) 918 event->overflow_handler = cpumsf_output_event_pid; 919 out: 920 return err; 921 } 922 923 static bool is_callchain_event(struct perf_event *event) 924 { 925 u64 sample_type = event->attr.sample_type; 926 927 return sample_type & (PERF_SAMPLE_CALLCHAIN | PERF_SAMPLE_REGS_USER | 928 PERF_SAMPLE_STACK_USER); 929 } 930 931 static int cpumsf_pmu_event_init(struct perf_event *event) 932 { 933 int err; 934 935 /* No support for taken branch sampling */ 936 /* No support for callchain, stacks and registers */ 937 if (has_branch_stack(event) || is_callchain_event(event)) 938 return -EOPNOTSUPP; 939 940 switch (event->attr.type) { 941 case PERF_TYPE_RAW: 942 if ((event->attr.config != PERF_EVENT_CPUM_SF) && 943 (event->attr.config != PERF_EVENT_CPUM_SF_DIAG)) 944 return -ENOENT; 945 break; 946 case PERF_TYPE_HARDWARE: 947 /* Support sampling of CPU cycles in addition to the 948 * counter facility. However, the counter facility 949 * is more precise and, hence, restrict this PMU to 950 * sampling events only. 951 */ 952 if (event->attr.config != PERF_COUNT_HW_CPU_CYCLES) 953 return -ENOENT; 954 if (!is_sampling_event(event)) 955 return -ENOENT; 956 break; 957 default: 958 return -ENOENT; 959 } 960 961 /* Force reset of idle/hv excludes regardless of what the 962 * user requested. 963 */ 964 if (event->attr.exclude_hv) 965 event->attr.exclude_hv = 0; 966 if (event->attr.exclude_idle) 967 event->attr.exclude_idle = 0; 968 969 err = __hw_perf_event_init(event); 970 if (unlikely(err)) 971 if (event->destroy) 972 event->destroy(event); 973 return err; 974 } 975 976 static void cpumsf_pmu_enable(struct pmu *pmu) 977 { 978 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 979 struct hw_perf_event *hwc; 980 int err; 981 982 if (cpuhw->flags & PMU_F_ENABLED) 983 return; 984 985 if (cpuhw->flags & PMU_F_ERR_MASK) 986 return; 987 988 /* Check whether to extent the sampling buffer. 989 * 990 * Two conditions trigger an increase of the sampling buffer for a 991 * perf event: 992 * 1. Postponed buffer allocations from the event initialization. 993 * 2. Sampling overflows that contribute to pending allocations. 994 * 995 * Note that the extend_sampling_buffer() function disables the sampling 996 * facility, but it can be fully re-enabled using sampling controls that 997 * have been saved in cpumsf_pmu_disable(). 998 */ 999 if (cpuhw->event) { 1000 hwc = &cpuhw->event->hw; 1001 if (!(SAMPL_DIAG_MODE(hwc))) { 1002 /* 1003 * Account number of overflow-designated 1004 * buffer extents 1005 */ 1006 sfb_account_overflows(cpuhw, hwc); 1007 extend_sampling_buffer(&cpuhw->sfb, hwc); 1008 } 1009 /* Rate may be adjusted with ioctl() */ 1010 cpuhw->lsctl.interval = SAMPL_RATE(&cpuhw->event->hw); 1011 } 1012 1013 /* (Re)enable the PMU and sampling facility */ 1014 cpuhw->flags |= PMU_F_ENABLED; 1015 barrier(); 1016 1017 err = lsctl(&cpuhw->lsctl); 1018 if (err) { 1019 cpuhw->flags &= ~PMU_F_ENABLED; 1020 pr_err("Loading sampling controls failed: op 1 err %i\n", err); 1021 return; 1022 } 1023 1024 /* Load current program parameter */ 1025 lpp(&S390_lowcore.lpp); 1026 1027 debug_sprintf_event(sfdbg, 6, "%s: es %i cs %i ed %i cd %i " 1028 "interval %#lx tear %#lx dear %#lx\n", __func__, 1029 cpuhw->lsctl.es, cpuhw->lsctl.cs, cpuhw->lsctl.ed, 1030 cpuhw->lsctl.cd, cpuhw->lsctl.interval, 1031 cpuhw->lsctl.tear, cpuhw->lsctl.dear); 1032 } 1033 1034 static void cpumsf_pmu_disable(struct pmu *pmu) 1035 { 1036 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 1037 struct hws_lsctl_request_block inactive; 1038 struct hws_qsi_info_block si; 1039 int err; 1040 1041 if (!(cpuhw->flags & PMU_F_ENABLED)) 1042 return; 1043 1044 if (cpuhw->flags & PMU_F_ERR_MASK) 1045 return; 1046 1047 /* Switch off sampling activation control */ 1048 inactive = cpuhw->lsctl; 1049 inactive.cs = 0; 1050 inactive.cd = 0; 1051 1052 err = lsctl(&inactive); 1053 if (err) { 1054 pr_err("Loading sampling controls failed: op 2 err %i\n", err); 1055 return; 1056 } 1057 1058 /* Save state of TEAR and DEAR register contents */ 1059 err = qsi(&si); 1060 if (!err) { 1061 /* TEAR/DEAR values are valid only if the sampling facility is 1062 * enabled. Note that cpumsf_pmu_disable() might be called even 1063 * for a disabled sampling facility because cpumsf_pmu_enable() 1064 * controls the enable/disable state. 1065 */ 1066 if (si.es) { 1067 cpuhw->lsctl.tear = si.tear; 1068 cpuhw->lsctl.dear = si.dear; 1069 } 1070 } else 1071 debug_sprintf_event(sfdbg, 3, "%s: qsi() failed with err %i\n", 1072 __func__, err); 1073 1074 cpuhw->flags &= ~PMU_F_ENABLED; 1075 } 1076 1077 /* perf_exclude_event() - Filter event 1078 * @event: The perf event 1079 * @regs: pt_regs structure 1080 * @sde_regs: Sample-data-entry (sde) regs structure 1081 * 1082 * Filter perf events according to their exclude specification. 1083 * 1084 * Return non-zero if the event shall be excluded. 1085 */ 1086 static int perf_exclude_event(struct perf_event *event, struct pt_regs *regs, 1087 struct perf_sf_sde_regs *sde_regs) 1088 { 1089 if (event->attr.exclude_user && user_mode(regs)) 1090 return 1; 1091 if (event->attr.exclude_kernel && !user_mode(regs)) 1092 return 1; 1093 if (event->attr.exclude_guest && sde_regs->in_guest) 1094 return 1; 1095 if (event->attr.exclude_host && !sde_regs->in_guest) 1096 return 1; 1097 return 0; 1098 } 1099 1100 /* perf_push_sample() - Push samples to perf 1101 * @event: The perf event 1102 * @sample: Hardware sample data 1103 * 1104 * Use the hardware sample data to create perf event sample. The sample 1105 * is the pushed to the event subsystem and the function checks for 1106 * possible event overflows. If an event overflow occurs, the PMU is 1107 * stopped. 1108 * 1109 * Return non-zero if an event overflow occurred. 1110 */ 1111 static int perf_push_sample(struct perf_event *event, 1112 struct hws_basic_entry *basic) 1113 { 1114 int overflow; 1115 struct pt_regs regs; 1116 struct perf_sf_sde_regs *sde_regs; 1117 struct perf_sample_data data; 1118 1119 /* Setup perf sample */ 1120 perf_sample_data_init(&data, 0, event->hw.last_period); 1121 1122 /* Setup pt_regs to look like an CPU-measurement external interrupt 1123 * using the Program Request Alert code. The regs.int_parm_long 1124 * field which is unused contains additional sample-data-entry related 1125 * indicators. 1126 */ 1127 memset(®s, 0, sizeof(regs)); 1128 regs.int_code = 0x1407; 1129 regs.int_parm = CPU_MF_INT_SF_PRA; 1130 sde_regs = (struct perf_sf_sde_regs *) ®s.int_parm_long; 1131 1132 psw_bits(regs.psw).ia = basic->ia; 1133 psw_bits(regs.psw).dat = basic->T; 1134 psw_bits(regs.psw).wait = basic->W; 1135 psw_bits(regs.psw).pstate = basic->P; 1136 psw_bits(regs.psw).as = basic->AS; 1137 1138 /* 1139 * Use the hardware provided configuration level to decide if the 1140 * sample belongs to a guest or host. If that is not available, 1141 * fall back to the following heuristics: 1142 * A non-zero guest program parameter always indicates a guest 1143 * sample. Some early samples or samples from guests without 1144 * lpp usage would be misaccounted to the host. We use the asn 1145 * value as an addon heuristic to detect most of these guest samples. 1146 * If the value differs from 0xffff (the host value), we assume to 1147 * be a KVM guest. 1148 */ 1149 switch (basic->CL) { 1150 case 1: /* logical partition */ 1151 sde_regs->in_guest = 0; 1152 break; 1153 case 2: /* virtual machine */ 1154 sde_regs->in_guest = 1; 1155 break; 1156 default: /* old machine, use heuristics */ 1157 if (basic->gpp || basic->prim_asn != 0xffff) 1158 sde_regs->in_guest = 1; 1159 break; 1160 } 1161 1162 /* 1163 * Store the PID value from the sample-data-entry to be 1164 * processed and resolved by cpumsf_output_event_pid(). 1165 */ 1166 data.tid_entry.pid = basic->hpp & LPP_PID_MASK; 1167 1168 overflow = 0; 1169 if (perf_exclude_event(event, ®s, sde_regs)) 1170 goto out; 1171 if (perf_event_overflow(event, &data, ®s)) { 1172 overflow = 1; 1173 event->pmu->stop(event, 0); 1174 } 1175 perf_event_update_userpage(event); 1176 out: 1177 return overflow; 1178 } 1179 1180 static void perf_event_count_update(struct perf_event *event, u64 count) 1181 { 1182 local64_add(count, &event->count); 1183 } 1184 1185 /* hw_collect_samples() - Walk through a sample-data-block and collect samples 1186 * @event: The perf event 1187 * @sdbt: Sample-data-block table 1188 * @overflow: Event overflow counter 1189 * 1190 * Walks through a sample-data-block and collects sampling data entries that are 1191 * then pushed to the perf event subsystem. Depending on the sampling function, 1192 * there can be either basic-sampling or combined-sampling data entries. A 1193 * combined-sampling data entry consists of a basic- and a diagnostic-sampling 1194 * data entry. The sampling function is determined by the flags in the perf 1195 * event hardware structure. The function always works with a combined-sampling 1196 * data entry but ignores the the diagnostic portion if it is not available. 1197 * 1198 * Note that the implementation focuses on basic-sampling data entries and, if 1199 * such an entry is not valid, the entire combined-sampling data entry is 1200 * ignored. 1201 * 1202 * The overflow variables counts the number of samples that has been discarded 1203 * due to a perf event overflow. 1204 */ 1205 static void hw_collect_samples(struct perf_event *event, unsigned long *sdbt, 1206 unsigned long long *overflow) 1207 { 1208 struct hws_trailer_entry *te; 1209 struct hws_basic_entry *sample; 1210 1211 te = trailer_entry_ptr((unsigned long)sdbt); 1212 sample = (struct hws_basic_entry *)sdbt; 1213 while ((unsigned long *)sample < (unsigned long *)te) { 1214 /* Check for an empty sample */ 1215 if (!sample->def || sample->LS) 1216 break; 1217 1218 /* Update perf event period */ 1219 perf_event_count_update(event, SAMPL_RATE(&event->hw)); 1220 1221 /* Check whether sample is valid */ 1222 if (sample->def == 0x0001) { 1223 /* If an event overflow occurred, the PMU is stopped to 1224 * throttle event delivery. Remaining sample data is 1225 * discarded. 1226 */ 1227 if (!*overflow) { 1228 /* Check whether sample is consistent */ 1229 if (sample->I == 0 && sample->W == 0) { 1230 /* Deliver sample data to perf */ 1231 *overflow = perf_push_sample(event, 1232 sample); 1233 } 1234 } else 1235 /* Count discarded samples */ 1236 *overflow += 1; 1237 } else { 1238 debug_sprintf_event(sfdbg, 4, 1239 "%s: Found unknown" 1240 " sampling data entry: te->f %i" 1241 " basic.def %#4x (%p)\n", __func__, 1242 te->header.f, sample->def, sample); 1243 /* Sample slot is not yet written or other record. 1244 * 1245 * This condition can occur if the buffer was reused 1246 * from a combined basic- and diagnostic-sampling. 1247 * If only basic-sampling is then active, entries are 1248 * written into the larger diagnostic entries. 1249 * This is typically the case for sample-data-blocks 1250 * that are not full. Stop processing if the first 1251 * invalid format was detected. 1252 */ 1253 if (!te->header.f) 1254 break; 1255 } 1256 1257 /* Reset sample slot and advance to next sample */ 1258 sample->def = 0; 1259 sample++; 1260 } 1261 } 1262 1263 /* hw_perf_event_update() - Process sampling buffer 1264 * @event: The perf event 1265 * @flush_all: Flag to also flush partially filled sample-data-blocks 1266 * 1267 * Processes the sampling buffer and create perf event samples. 1268 * The sampling buffer position are retrieved and saved in the TEAR_REG 1269 * register of the specified perf event. 1270 * 1271 * Only full sample-data-blocks are processed. Specify the flush_all flag 1272 * to also walk through partially filled sample-data-blocks. 1273 */ 1274 static void hw_perf_event_update(struct perf_event *event, int flush_all) 1275 { 1276 unsigned long long event_overflow, sampl_overflow, num_sdb; 1277 union hws_trailer_header old, prev, new; 1278 struct hw_perf_event *hwc = &event->hw; 1279 struct hws_trailer_entry *te; 1280 unsigned long *sdbt, sdb; 1281 int done; 1282 1283 /* 1284 * AUX buffer is used when in diagnostic sampling mode. 1285 * No perf events/samples are created. 1286 */ 1287 if (SAMPL_DIAG_MODE(&event->hw)) 1288 return; 1289 1290 sdbt = (unsigned long *)TEAR_REG(hwc); 1291 done = event_overflow = sampl_overflow = num_sdb = 0; 1292 while (!done) { 1293 /* Get the trailer entry of the sample-data-block */ 1294 sdb = (unsigned long)phys_to_virt(*sdbt); 1295 te = trailer_entry_ptr(sdb); 1296 1297 /* Leave loop if no more work to do (block full indicator) */ 1298 if (!te->header.f) { 1299 done = 1; 1300 if (!flush_all) 1301 break; 1302 } 1303 1304 /* Check the sample overflow count */ 1305 if (te->header.overflow) 1306 /* Account sample overflows and, if a particular limit 1307 * is reached, extend the sampling buffer. 1308 * For details, see sfb_account_overflows(). 1309 */ 1310 sampl_overflow += te->header.overflow; 1311 1312 /* Timestamps are valid for full sample-data-blocks only */ 1313 debug_sprintf_event(sfdbg, 6, "%s: sdbt %#lx/%#lx " 1314 "overflow %llu timestamp %#llx\n", 1315 __func__, sdb, (unsigned long)sdbt, 1316 te->header.overflow, 1317 (te->header.f) ? trailer_timestamp(te) : 0ULL); 1318 1319 /* Collect all samples from a single sample-data-block and 1320 * flag if an (perf) event overflow happened. If so, the PMU 1321 * is stopped and remaining samples will be discarded. 1322 */ 1323 hw_collect_samples(event, (unsigned long *)sdb, &event_overflow); 1324 num_sdb++; 1325 1326 /* Reset trailer (using compare-double-and-swap) */ 1327 prev.val = READ_ONCE_ALIGNED_128(te->header.val); 1328 do { 1329 old.val = prev.val; 1330 new.val = prev.val; 1331 new.f = 0; 1332 new.a = 1; 1333 new.overflow = 0; 1334 prev.val = cmpxchg128(&te->header.val, old.val, new.val); 1335 } while (prev.val != old.val); 1336 1337 /* Advance to next sample-data-block */ 1338 sdbt++; 1339 if (is_link_entry(sdbt)) 1340 sdbt = get_next_sdbt(sdbt); 1341 1342 /* Update event hardware registers */ 1343 TEAR_REG(hwc) = (unsigned long) sdbt; 1344 1345 /* Stop processing sample-data if all samples of the current 1346 * sample-data-block were flushed even if it was not full. 1347 */ 1348 if (flush_all && done) 1349 break; 1350 } 1351 1352 /* Account sample overflows in the event hardware structure */ 1353 if (sampl_overflow) 1354 OVERFLOW_REG(hwc) = DIV_ROUND_UP(OVERFLOW_REG(hwc) + 1355 sampl_overflow, 1 + num_sdb); 1356 1357 /* Perf_event_overflow() and perf_event_account_interrupt() limit 1358 * the interrupt rate to an upper limit. Roughly 1000 samples per 1359 * task tick. 1360 * Hitting this limit results in a large number 1361 * of throttled REF_REPORT_THROTTLE entries and the samples 1362 * are dropped. 1363 * Slightly increase the interval to avoid hitting this limit. 1364 */ 1365 if (event_overflow) { 1366 SAMPL_RATE(hwc) += DIV_ROUND_UP(SAMPL_RATE(hwc), 10); 1367 debug_sprintf_event(sfdbg, 1, "%s: rate adjustment %ld\n", 1368 __func__, 1369 DIV_ROUND_UP(SAMPL_RATE(hwc), 10)); 1370 } 1371 1372 if (sampl_overflow || event_overflow) 1373 debug_sprintf_event(sfdbg, 4, "%s: " 1374 "overflows: sample %llu event %llu" 1375 " total %llu num_sdb %llu\n", 1376 __func__, sampl_overflow, event_overflow, 1377 OVERFLOW_REG(hwc), num_sdb); 1378 } 1379 1380 static inline unsigned long aux_sdb_index(struct aux_buffer *aux, 1381 unsigned long i) 1382 { 1383 return i % aux->sfb.num_sdb; 1384 } 1385 1386 static inline unsigned long aux_sdb_num(unsigned long start, unsigned long end) 1387 { 1388 return end >= start ? end - start + 1 : 0; 1389 } 1390 1391 static inline unsigned long aux_sdb_num_alert(struct aux_buffer *aux) 1392 { 1393 return aux_sdb_num(aux->head, aux->alert_mark); 1394 } 1395 1396 static inline unsigned long aux_sdb_num_empty(struct aux_buffer *aux) 1397 { 1398 return aux_sdb_num(aux->head, aux->empty_mark); 1399 } 1400 1401 /* 1402 * Get trailer entry by index of SDB. 1403 */ 1404 static struct hws_trailer_entry *aux_sdb_trailer(struct aux_buffer *aux, 1405 unsigned long index) 1406 { 1407 unsigned long sdb; 1408 1409 index = aux_sdb_index(aux, index); 1410 sdb = aux->sdb_index[index]; 1411 return trailer_entry_ptr(sdb); 1412 } 1413 1414 /* 1415 * Finish sampling on the cpu. Called by cpumsf_pmu_del() with pmu 1416 * disabled. Collect the full SDBs in AUX buffer which have not reached 1417 * the point of alert indicator. And ignore the SDBs which are not 1418 * full. 1419 * 1420 * 1. Scan SDBs to see how much data is there and consume them. 1421 * 2. Remove alert indicator in the buffer. 1422 */ 1423 static void aux_output_end(struct perf_output_handle *handle) 1424 { 1425 unsigned long i, range_scan, idx; 1426 struct aux_buffer *aux; 1427 struct hws_trailer_entry *te; 1428 1429 aux = perf_get_aux(handle); 1430 if (!aux) 1431 return; 1432 1433 range_scan = aux_sdb_num_alert(aux); 1434 for (i = 0, idx = aux->head; i < range_scan; i++, idx++) { 1435 te = aux_sdb_trailer(aux, idx); 1436 if (!te->header.f) 1437 break; 1438 } 1439 /* i is num of SDBs which are full */ 1440 perf_aux_output_end(handle, i << PAGE_SHIFT); 1441 1442 /* Remove alert indicators in the buffer */ 1443 te = aux_sdb_trailer(aux, aux->alert_mark); 1444 te->header.a = 0; 1445 1446 debug_sprintf_event(sfdbg, 6, "%s: SDBs %ld range %ld head %ld\n", 1447 __func__, i, range_scan, aux->head); 1448 } 1449 1450 /* 1451 * Start sampling on the CPU. Called by cpumsf_pmu_add() when an event 1452 * is first added to the CPU or rescheduled again to the CPU. It is called 1453 * with pmu disabled. 1454 * 1455 * 1. Reset the trailer of SDBs to get ready for new data. 1456 * 2. Tell the hardware where to put the data by reset the SDBs buffer 1457 * head(tear/dear). 1458 */ 1459 static int aux_output_begin(struct perf_output_handle *handle, 1460 struct aux_buffer *aux, 1461 struct cpu_hw_sf *cpuhw) 1462 { 1463 unsigned long range, i, range_scan, idx, head, base, offset; 1464 struct hws_trailer_entry *te; 1465 1466 if (WARN_ON_ONCE(handle->head & ~PAGE_MASK)) 1467 return -EINVAL; 1468 1469 aux->head = handle->head >> PAGE_SHIFT; 1470 range = (handle->size + 1) >> PAGE_SHIFT; 1471 if (range <= 1) 1472 return -ENOMEM; 1473 1474 /* 1475 * SDBs between aux->head and aux->empty_mark are already ready 1476 * for new data. range_scan is num of SDBs not within them. 1477 */ 1478 debug_sprintf_event(sfdbg, 6, 1479 "%s: range %ld head %ld alert %ld empty %ld\n", 1480 __func__, range, aux->head, aux->alert_mark, 1481 aux->empty_mark); 1482 if (range > aux_sdb_num_empty(aux)) { 1483 range_scan = range - aux_sdb_num_empty(aux); 1484 idx = aux->empty_mark + 1; 1485 for (i = 0; i < range_scan; i++, idx++) { 1486 te = aux_sdb_trailer(aux, idx); 1487 te->header.f = 0; 1488 te->header.a = 0; 1489 te->header.overflow = 0; 1490 } 1491 /* Save the position of empty SDBs */ 1492 aux->empty_mark = aux->head + range - 1; 1493 } 1494 1495 /* Set alert indicator */ 1496 aux->alert_mark = aux->head + range/2 - 1; 1497 te = aux_sdb_trailer(aux, aux->alert_mark); 1498 te->header.a = 1; 1499 1500 /* Reset hardware buffer head */ 1501 head = aux_sdb_index(aux, aux->head); 1502 base = aux->sdbt_index[head / CPUM_SF_SDB_PER_TABLE]; 1503 offset = head % CPUM_SF_SDB_PER_TABLE; 1504 cpuhw->lsctl.tear = virt_to_phys((void *)base) + offset * sizeof(unsigned long); 1505 cpuhw->lsctl.dear = virt_to_phys((void *)aux->sdb_index[head]); 1506 1507 debug_sprintf_event(sfdbg, 6, "%s: head %ld alert %ld empty %ld " 1508 "index %ld tear %#lx dear %#lx\n", __func__, 1509 aux->head, aux->alert_mark, aux->empty_mark, 1510 head / CPUM_SF_SDB_PER_TABLE, 1511 cpuhw->lsctl.tear, cpuhw->lsctl.dear); 1512 1513 return 0; 1514 } 1515 1516 /* 1517 * Set alert indicator on SDB at index @alert_index while sampler is running. 1518 * 1519 * Return true if successfully. 1520 * Return false if full indicator is already set by hardware sampler. 1521 */ 1522 static bool aux_set_alert(struct aux_buffer *aux, unsigned long alert_index, 1523 unsigned long long *overflow) 1524 { 1525 union hws_trailer_header old, prev, new; 1526 struct hws_trailer_entry *te; 1527 1528 te = aux_sdb_trailer(aux, alert_index); 1529 prev.val = READ_ONCE_ALIGNED_128(te->header.val); 1530 do { 1531 old.val = prev.val; 1532 new.val = prev.val; 1533 *overflow = old.overflow; 1534 if (old.f) { 1535 /* 1536 * SDB is already set by hardware. 1537 * Abort and try to set somewhere 1538 * behind. 1539 */ 1540 return false; 1541 } 1542 new.a = 1; 1543 new.overflow = 0; 1544 prev.val = cmpxchg128(&te->header.val, old.val, new.val); 1545 } while (prev.val != old.val); 1546 return true; 1547 } 1548 1549 /* 1550 * aux_reset_buffer() - Scan and setup SDBs for new samples 1551 * @aux: The AUX buffer to set 1552 * @range: The range of SDBs to scan started from aux->head 1553 * @overflow: Set to overflow count 1554 * 1555 * Set alert indicator on the SDB at index of aux->alert_mark. If this SDB is 1556 * marked as empty, check if it is already set full by the hardware sampler. 1557 * If yes, that means new data is already there before we can set an alert 1558 * indicator. Caller should try to set alert indicator to some position behind. 1559 * 1560 * Scan the SDBs in AUX buffer from behind aux->empty_mark. They are used 1561 * previously and have already been consumed by user space. Reset these SDBs 1562 * (clear full indicator and alert indicator) for new data. 1563 * If aux->alert_mark fall in this area, just set it. Overflow count is 1564 * recorded while scanning. 1565 * 1566 * SDBs between aux->head and aux->empty_mark are already reset at last time. 1567 * and ready for new samples. So scanning on this area could be skipped. 1568 * 1569 * Return true if alert indicator is set successfully and false if not. 1570 */ 1571 static bool aux_reset_buffer(struct aux_buffer *aux, unsigned long range, 1572 unsigned long long *overflow) 1573 { 1574 unsigned long i, range_scan, idx, idx_old; 1575 union hws_trailer_header old, prev, new; 1576 unsigned long long orig_overflow; 1577 struct hws_trailer_entry *te; 1578 1579 debug_sprintf_event(sfdbg, 6, "%s: range %ld head %ld alert %ld " 1580 "empty %ld\n", __func__, range, aux->head, 1581 aux->alert_mark, aux->empty_mark); 1582 if (range <= aux_sdb_num_empty(aux)) 1583 /* 1584 * No need to scan. All SDBs in range are marked as empty. 1585 * Just set alert indicator. Should check race with hardware 1586 * sampler. 1587 */ 1588 return aux_set_alert(aux, aux->alert_mark, overflow); 1589 1590 if (aux->alert_mark <= aux->empty_mark) 1591 /* 1592 * Set alert indicator on empty SDB. Should check race 1593 * with hardware sampler. 1594 */ 1595 if (!aux_set_alert(aux, aux->alert_mark, overflow)) 1596 return false; 1597 1598 /* 1599 * Scan the SDBs to clear full and alert indicator used previously. 1600 * Start scanning from one SDB behind empty_mark. If the new alert 1601 * indicator fall into this range, set it. 1602 */ 1603 range_scan = range - aux_sdb_num_empty(aux); 1604 idx_old = idx = aux->empty_mark + 1; 1605 for (i = 0; i < range_scan; i++, idx++) { 1606 te = aux_sdb_trailer(aux, idx); 1607 prev.val = READ_ONCE_ALIGNED_128(te->header.val); 1608 do { 1609 old.val = prev.val; 1610 new.val = prev.val; 1611 orig_overflow = old.overflow; 1612 new.f = 0; 1613 new.overflow = 0; 1614 if (idx == aux->alert_mark) 1615 new.a = 1; 1616 else 1617 new.a = 0; 1618 prev.val = cmpxchg128(&te->header.val, old.val, new.val); 1619 } while (prev.val != old.val); 1620 *overflow += orig_overflow; 1621 } 1622 1623 /* Update empty_mark to new position */ 1624 aux->empty_mark = aux->head + range - 1; 1625 1626 debug_sprintf_event(sfdbg, 6, "%s: range_scan %ld idx %ld..%ld " 1627 "empty %ld\n", __func__, range_scan, idx_old, 1628 idx - 1, aux->empty_mark); 1629 return true; 1630 } 1631 1632 /* 1633 * Measurement alert handler for diagnostic mode sampling. 1634 */ 1635 static void hw_collect_aux(struct cpu_hw_sf *cpuhw) 1636 { 1637 struct aux_buffer *aux; 1638 int done = 0; 1639 unsigned long range = 0, size; 1640 unsigned long long overflow = 0; 1641 struct perf_output_handle *handle = &cpuhw->handle; 1642 unsigned long num_sdb; 1643 1644 aux = perf_get_aux(handle); 1645 if (WARN_ON_ONCE(!aux)) 1646 return; 1647 1648 /* Inform user space new data arrived */ 1649 size = aux_sdb_num_alert(aux) << PAGE_SHIFT; 1650 debug_sprintf_event(sfdbg, 6, "%s: #alert %ld\n", __func__, 1651 size >> PAGE_SHIFT); 1652 perf_aux_output_end(handle, size); 1653 1654 num_sdb = aux->sfb.num_sdb; 1655 while (!done) { 1656 /* Get an output handle */ 1657 aux = perf_aux_output_begin(handle, cpuhw->event); 1658 if (handle->size == 0) { 1659 pr_err("The AUX buffer with %lu pages for the " 1660 "diagnostic-sampling mode is full\n", 1661 num_sdb); 1662 break; 1663 } 1664 if (WARN_ON_ONCE(!aux)) 1665 return; 1666 1667 /* Update head and alert_mark to new position */ 1668 aux->head = handle->head >> PAGE_SHIFT; 1669 range = (handle->size + 1) >> PAGE_SHIFT; 1670 if (range == 1) 1671 aux->alert_mark = aux->head; 1672 else 1673 aux->alert_mark = aux->head + range/2 - 1; 1674 1675 if (aux_reset_buffer(aux, range, &overflow)) { 1676 if (!overflow) { 1677 done = 1; 1678 break; 1679 } 1680 size = range << PAGE_SHIFT; 1681 perf_aux_output_end(&cpuhw->handle, size); 1682 pr_err("Sample data caused the AUX buffer with %lu " 1683 "pages to overflow\n", aux->sfb.num_sdb); 1684 debug_sprintf_event(sfdbg, 1, "%s: head %ld range %ld " 1685 "overflow %lld\n", __func__, 1686 aux->head, range, overflow); 1687 } else { 1688 size = aux_sdb_num_alert(aux) << PAGE_SHIFT; 1689 perf_aux_output_end(&cpuhw->handle, size); 1690 debug_sprintf_event(sfdbg, 6, "%s: head %ld alert %ld " 1691 "already full, try another\n", 1692 __func__, 1693 aux->head, aux->alert_mark); 1694 } 1695 } 1696 1697 if (done) 1698 debug_sprintf_event(sfdbg, 6, "%s: head %ld alert %ld " 1699 "empty %ld\n", __func__, aux->head, 1700 aux->alert_mark, aux->empty_mark); 1701 } 1702 1703 /* 1704 * Callback when freeing AUX buffers. 1705 */ 1706 static void aux_buffer_free(void *data) 1707 { 1708 struct aux_buffer *aux = data; 1709 unsigned long i, num_sdbt; 1710 1711 if (!aux) 1712 return; 1713 1714 /* Free SDBT. SDB is freed by the caller */ 1715 num_sdbt = aux->sfb.num_sdbt; 1716 for (i = 0; i < num_sdbt; i++) 1717 free_page(aux->sdbt_index[i]); 1718 1719 kfree(aux->sdbt_index); 1720 kfree(aux->sdb_index); 1721 kfree(aux); 1722 1723 debug_sprintf_event(sfdbg, 4, "%s: SDBTs %lu\n", __func__, num_sdbt); 1724 } 1725 1726 static void aux_sdb_init(unsigned long sdb) 1727 { 1728 struct hws_trailer_entry *te; 1729 1730 te = trailer_entry_ptr(sdb); 1731 1732 /* Save clock base */ 1733 te->clock_base = 1; 1734 te->progusage2 = tod_clock_base.tod; 1735 } 1736 1737 /* 1738 * aux_buffer_setup() - Setup AUX buffer for diagnostic mode sampling 1739 * @event: Event the buffer is setup for, event->cpu == -1 means current 1740 * @pages: Array of pointers to buffer pages passed from perf core 1741 * @nr_pages: Total pages 1742 * @snapshot: Flag for snapshot mode 1743 * 1744 * This is the callback when setup an event using AUX buffer. Perf tool can 1745 * trigger this by an additional mmap() call on the event. Unlike the buffer 1746 * for basic samples, AUX buffer belongs to the event. It is scheduled with 1747 * the task among online cpus when it is a per-thread event. 1748 * 1749 * Return the private AUX buffer structure if success or NULL if fails. 1750 */ 1751 static void *aux_buffer_setup(struct perf_event *event, void **pages, 1752 int nr_pages, bool snapshot) 1753 { 1754 struct sf_buffer *sfb; 1755 struct aux_buffer *aux; 1756 unsigned long *new, *tail; 1757 int i, n_sdbt; 1758 1759 if (!nr_pages || !pages) 1760 return NULL; 1761 1762 if (nr_pages > CPUM_SF_MAX_SDB * CPUM_SF_SDB_DIAG_FACTOR) { 1763 pr_err("AUX buffer size (%i pages) is larger than the " 1764 "maximum sampling buffer limit\n", 1765 nr_pages); 1766 return NULL; 1767 } else if (nr_pages < CPUM_SF_MIN_SDB * CPUM_SF_SDB_DIAG_FACTOR) { 1768 pr_err("AUX buffer size (%i pages) is less than the " 1769 "minimum sampling buffer limit\n", 1770 nr_pages); 1771 return NULL; 1772 } 1773 1774 /* Allocate aux_buffer struct for the event */ 1775 aux = kzalloc(sizeof(struct aux_buffer), GFP_KERNEL); 1776 if (!aux) 1777 goto no_aux; 1778 sfb = &aux->sfb; 1779 1780 /* Allocate sdbt_index for fast reference */ 1781 n_sdbt = DIV_ROUND_UP(nr_pages, CPUM_SF_SDB_PER_TABLE); 1782 aux->sdbt_index = kmalloc_array(n_sdbt, sizeof(void *), GFP_KERNEL); 1783 if (!aux->sdbt_index) 1784 goto no_sdbt_index; 1785 1786 /* Allocate sdb_index for fast reference */ 1787 aux->sdb_index = kmalloc_array(nr_pages, sizeof(void *), GFP_KERNEL); 1788 if (!aux->sdb_index) 1789 goto no_sdb_index; 1790 1791 /* Allocate the first SDBT */ 1792 sfb->num_sdbt = 0; 1793 sfb->sdbt = (unsigned long *)get_zeroed_page(GFP_KERNEL); 1794 if (!sfb->sdbt) 1795 goto no_sdbt; 1796 aux->sdbt_index[sfb->num_sdbt++] = (unsigned long)sfb->sdbt; 1797 tail = sfb->tail = sfb->sdbt; 1798 1799 /* 1800 * Link the provided pages of AUX buffer to SDBT. 1801 * Allocate SDBT if needed. 1802 */ 1803 for (i = 0; i < nr_pages; i++, tail++) { 1804 if (require_table_link(tail)) { 1805 new = (unsigned long *)get_zeroed_page(GFP_KERNEL); 1806 if (!new) 1807 goto no_sdbt; 1808 aux->sdbt_index[sfb->num_sdbt++] = (unsigned long)new; 1809 /* Link current page to tail of chain */ 1810 *tail = virt_to_phys(new) + 1; 1811 tail = new; 1812 } 1813 /* Tail is the entry in a SDBT */ 1814 *tail = virt_to_phys(pages[i]); 1815 aux->sdb_index[i] = (unsigned long)pages[i]; 1816 aux_sdb_init((unsigned long)pages[i]); 1817 } 1818 sfb->num_sdb = nr_pages; 1819 1820 /* Link the last entry in the SDBT to the first SDBT */ 1821 *tail = virt_to_phys(sfb->sdbt) + 1; 1822 sfb->tail = tail; 1823 1824 /* 1825 * Initial all SDBs are zeroed. Mark it as empty. 1826 * So there is no need to clear the full indicator 1827 * when this event is first added. 1828 */ 1829 aux->empty_mark = sfb->num_sdb - 1; 1830 1831 debug_sprintf_event(sfdbg, 4, "%s: SDBTs %lu SDBs %lu\n", __func__, 1832 sfb->num_sdbt, sfb->num_sdb); 1833 1834 return aux; 1835 1836 no_sdbt: 1837 /* SDBs (AUX buffer pages) are freed by caller */ 1838 for (i = 0; i < sfb->num_sdbt; i++) 1839 free_page(aux->sdbt_index[i]); 1840 kfree(aux->sdb_index); 1841 no_sdb_index: 1842 kfree(aux->sdbt_index); 1843 no_sdbt_index: 1844 kfree(aux); 1845 no_aux: 1846 return NULL; 1847 } 1848 1849 static void cpumsf_pmu_read(struct perf_event *event) 1850 { 1851 /* Nothing to do ... updates are interrupt-driven */ 1852 } 1853 1854 /* Check if the new sampling period/frequency is appropriate. 1855 * 1856 * Return non-zero on error and zero on passed checks. 1857 */ 1858 static int cpumsf_pmu_check_period(struct perf_event *event, u64 value) 1859 { 1860 struct hws_qsi_info_block si; 1861 unsigned long rate; 1862 bool do_freq; 1863 1864 memset(&si, 0, sizeof(si)); 1865 if (event->cpu == -1) { 1866 if (qsi(&si)) 1867 return -ENODEV; 1868 } else { 1869 /* Event is pinned to a particular CPU, retrieve the per-CPU 1870 * sampling structure for accessing the CPU-specific QSI. 1871 */ 1872 struct cpu_hw_sf *cpuhw = &per_cpu(cpu_hw_sf, event->cpu); 1873 1874 si = cpuhw->qsi; 1875 } 1876 1877 do_freq = !!SAMPLE_FREQ_MODE(&event->hw); 1878 rate = getrate(do_freq, value, &si); 1879 if (!rate) 1880 return -EINVAL; 1881 1882 event->attr.sample_period = rate; 1883 SAMPL_RATE(&event->hw) = rate; 1884 hw_init_period(&event->hw, SAMPL_RATE(&event->hw)); 1885 debug_sprintf_event(sfdbg, 4, "%s:" 1886 " cpu %d value %#llx period %#llx freq %d\n", 1887 __func__, event->cpu, value, 1888 event->attr.sample_period, do_freq); 1889 return 0; 1890 } 1891 1892 /* Activate sampling control. 1893 * Next call of pmu_enable() starts sampling. 1894 */ 1895 static void cpumsf_pmu_start(struct perf_event *event, int flags) 1896 { 1897 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 1898 1899 if (WARN_ON_ONCE(!(event->hw.state & PERF_HES_STOPPED))) 1900 return; 1901 1902 if (flags & PERF_EF_RELOAD) 1903 WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE)); 1904 1905 perf_pmu_disable(event->pmu); 1906 event->hw.state = 0; 1907 cpuhw->lsctl.cs = 1; 1908 if (SAMPL_DIAG_MODE(&event->hw)) 1909 cpuhw->lsctl.cd = 1; 1910 perf_pmu_enable(event->pmu); 1911 } 1912 1913 /* Deactivate sampling control. 1914 * Next call of pmu_enable() stops sampling. 1915 */ 1916 static void cpumsf_pmu_stop(struct perf_event *event, int flags) 1917 { 1918 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 1919 1920 if (event->hw.state & PERF_HES_STOPPED) 1921 return; 1922 1923 perf_pmu_disable(event->pmu); 1924 cpuhw->lsctl.cs = 0; 1925 cpuhw->lsctl.cd = 0; 1926 event->hw.state |= PERF_HES_STOPPED; 1927 1928 if ((flags & PERF_EF_UPDATE) && !(event->hw.state & PERF_HES_UPTODATE)) { 1929 hw_perf_event_update(event, 1); 1930 event->hw.state |= PERF_HES_UPTODATE; 1931 } 1932 perf_pmu_enable(event->pmu); 1933 } 1934 1935 static int cpumsf_pmu_add(struct perf_event *event, int flags) 1936 { 1937 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 1938 struct aux_buffer *aux; 1939 int err; 1940 1941 if (cpuhw->flags & PMU_F_IN_USE) 1942 return -EAGAIN; 1943 1944 if (!SAMPL_DIAG_MODE(&event->hw) && !cpuhw->sfb.sdbt) 1945 return -EINVAL; 1946 1947 err = 0; 1948 perf_pmu_disable(event->pmu); 1949 1950 event->hw.state = PERF_HES_UPTODATE | PERF_HES_STOPPED; 1951 1952 /* Set up sampling controls. Always program the sampling register 1953 * using the SDB-table start. Reset TEAR_REG event hardware register 1954 * that is used by hw_perf_event_update() to store the sampling buffer 1955 * position after samples have been flushed. 1956 */ 1957 cpuhw->lsctl.s = 0; 1958 cpuhw->lsctl.h = 1; 1959 cpuhw->lsctl.interval = SAMPL_RATE(&event->hw); 1960 if (!SAMPL_DIAG_MODE(&event->hw)) { 1961 cpuhw->lsctl.tear = virt_to_phys(cpuhw->sfb.sdbt); 1962 cpuhw->lsctl.dear = *(unsigned long *)cpuhw->sfb.sdbt; 1963 TEAR_REG(&event->hw) = (unsigned long)cpuhw->sfb.sdbt; 1964 } 1965 1966 /* Ensure sampling functions are in the disabled state. If disabled, 1967 * switch on sampling enable control. */ 1968 if (WARN_ON_ONCE(cpuhw->lsctl.es == 1 || cpuhw->lsctl.ed == 1)) { 1969 err = -EAGAIN; 1970 goto out; 1971 } 1972 if (SAMPL_DIAG_MODE(&event->hw)) { 1973 aux = perf_aux_output_begin(&cpuhw->handle, event); 1974 if (!aux) { 1975 err = -EINVAL; 1976 goto out; 1977 } 1978 err = aux_output_begin(&cpuhw->handle, aux, cpuhw); 1979 if (err) 1980 goto out; 1981 cpuhw->lsctl.ed = 1; 1982 } 1983 cpuhw->lsctl.es = 1; 1984 1985 /* Set in_use flag and store event */ 1986 cpuhw->event = event; 1987 cpuhw->flags |= PMU_F_IN_USE; 1988 1989 if (flags & PERF_EF_START) 1990 cpumsf_pmu_start(event, PERF_EF_RELOAD); 1991 out: 1992 perf_event_update_userpage(event); 1993 perf_pmu_enable(event->pmu); 1994 return err; 1995 } 1996 1997 static void cpumsf_pmu_del(struct perf_event *event, int flags) 1998 { 1999 struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); 2000 2001 perf_pmu_disable(event->pmu); 2002 cpumsf_pmu_stop(event, PERF_EF_UPDATE); 2003 2004 cpuhw->lsctl.es = 0; 2005 cpuhw->lsctl.ed = 0; 2006 cpuhw->flags &= ~PMU_F_IN_USE; 2007 cpuhw->event = NULL; 2008 2009 if (SAMPL_DIAG_MODE(&event->hw)) 2010 aux_output_end(&cpuhw->handle); 2011 perf_event_update_userpage(event); 2012 perf_pmu_enable(event->pmu); 2013 } 2014 2015 CPUMF_EVENT_ATTR(SF, SF_CYCLES_BASIC, PERF_EVENT_CPUM_SF); 2016 CPUMF_EVENT_ATTR(SF, SF_CYCLES_BASIC_DIAG, PERF_EVENT_CPUM_SF_DIAG); 2017 2018 /* Attribute list for CPU_SF. 2019 * 2020 * The availablitiy depends on the CPU_MF sampling facility authorization 2021 * for basic + diagnositic samples. This is determined at initialization 2022 * time by the sampling facility device driver. 2023 * If the authorization for basic samples is turned off, it should be 2024 * also turned off for diagnostic sampling. 2025 * 2026 * During initialization of the device driver, check the authorization 2027 * level for diagnostic sampling and installs the attribute 2028 * file for diagnostic sampling if necessary. 2029 * 2030 * For now install a placeholder to reference all possible attributes: 2031 * SF_CYCLES_BASIC and SF_CYCLES_BASIC_DIAG. 2032 * Add another entry for the final NULL pointer. 2033 */ 2034 enum { 2035 SF_CYCLES_BASIC_ATTR_IDX = 0, 2036 SF_CYCLES_BASIC_DIAG_ATTR_IDX, 2037 SF_CYCLES_ATTR_MAX 2038 }; 2039 2040 static struct attribute *cpumsf_pmu_events_attr[SF_CYCLES_ATTR_MAX + 1] = { 2041 [SF_CYCLES_BASIC_ATTR_IDX] = CPUMF_EVENT_PTR(SF, SF_CYCLES_BASIC) 2042 }; 2043 2044 PMU_FORMAT_ATTR(event, "config:0-63"); 2045 2046 static struct attribute *cpumsf_pmu_format_attr[] = { 2047 &format_attr_event.attr, 2048 NULL, 2049 }; 2050 2051 static struct attribute_group cpumsf_pmu_events_group = { 2052 .name = "events", 2053 .attrs = cpumsf_pmu_events_attr, 2054 }; 2055 2056 static struct attribute_group cpumsf_pmu_format_group = { 2057 .name = "format", 2058 .attrs = cpumsf_pmu_format_attr, 2059 }; 2060 2061 static const struct attribute_group *cpumsf_pmu_attr_groups[] = { 2062 &cpumsf_pmu_events_group, 2063 &cpumsf_pmu_format_group, 2064 NULL, 2065 }; 2066 2067 static struct pmu cpumf_sampling = { 2068 .pmu_enable = cpumsf_pmu_enable, 2069 .pmu_disable = cpumsf_pmu_disable, 2070 2071 .event_init = cpumsf_pmu_event_init, 2072 .add = cpumsf_pmu_add, 2073 .del = cpumsf_pmu_del, 2074 2075 .start = cpumsf_pmu_start, 2076 .stop = cpumsf_pmu_stop, 2077 .read = cpumsf_pmu_read, 2078 2079 .attr_groups = cpumsf_pmu_attr_groups, 2080 2081 .setup_aux = aux_buffer_setup, 2082 .free_aux = aux_buffer_free, 2083 2084 .check_period = cpumsf_pmu_check_period, 2085 }; 2086 2087 static void cpumf_measurement_alert(struct ext_code ext_code, 2088 unsigned int alert, unsigned long unused) 2089 { 2090 struct cpu_hw_sf *cpuhw; 2091 2092 if (!(alert & CPU_MF_INT_SF_MASK)) 2093 return; 2094 inc_irq_stat(IRQEXT_CMS); 2095 cpuhw = this_cpu_ptr(&cpu_hw_sf); 2096 2097 /* Measurement alerts are shared and might happen when the PMU 2098 * is not reserved. Ignore these alerts in this case. */ 2099 if (!(cpuhw->flags & PMU_F_RESERVED)) 2100 return; 2101 2102 /* The processing below must take care of multiple alert events that 2103 * might be indicated concurrently. */ 2104 2105 /* Program alert request */ 2106 if (alert & CPU_MF_INT_SF_PRA) { 2107 if (cpuhw->flags & PMU_F_IN_USE) 2108 if (SAMPL_DIAG_MODE(&cpuhw->event->hw)) 2109 hw_collect_aux(cpuhw); 2110 else 2111 hw_perf_event_update(cpuhw->event, 0); 2112 else 2113 WARN_ON_ONCE(!(cpuhw->flags & PMU_F_IN_USE)); 2114 } 2115 2116 /* Report measurement alerts only for non-PRA codes */ 2117 if (alert != CPU_MF_INT_SF_PRA) 2118 debug_sprintf_event(sfdbg, 6, "%s: alert %#x\n", __func__, 2119 alert); 2120 2121 /* Sampling authorization change request */ 2122 if (alert & CPU_MF_INT_SF_SACA) 2123 qsi(&cpuhw->qsi); 2124 2125 /* Loss of sample data due to high-priority machine activities */ 2126 if (alert & CPU_MF_INT_SF_LSDA) { 2127 pr_err("Sample data was lost\n"); 2128 cpuhw->flags |= PMU_F_ERR_LSDA; 2129 sf_disable(); 2130 } 2131 2132 /* Invalid sampling buffer entry */ 2133 if (alert & (CPU_MF_INT_SF_IAE|CPU_MF_INT_SF_ISE)) { 2134 pr_err("A sampling buffer entry is incorrect (alert=0x%x)\n", 2135 alert); 2136 cpuhw->flags |= PMU_F_ERR_IBE; 2137 sf_disable(); 2138 } 2139 } 2140 2141 static int cpusf_pmu_setup(unsigned int cpu, int flags) 2142 { 2143 /* Ignore the notification if no events are scheduled on the PMU. 2144 * This might be racy... 2145 */ 2146 if (!atomic_read(&num_events)) 2147 return 0; 2148 2149 local_irq_disable(); 2150 setup_pmc_cpu(&flags); 2151 local_irq_enable(); 2152 return 0; 2153 } 2154 2155 static int s390_pmu_sf_online_cpu(unsigned int cpu) 2156 { 2157 return cpusf_pmu_setup(cpu, PMC_INIT); 2158 } 2159 2160 static int s390_pmu_sf_offline_cpu(unsigned int cpu) 2161 { 2162 return cpusf_pmu_setup(cpu, PMC_RELEASE); 2163 } 2164 2165 static int param_get_sfb_size(char *buffer, const struct kernel_param *kp) 2166 { 2167 if (!cpum_sf_avail()) 2168 return -ENODEV; 2169 return sprintf(buffer, "%lu,%lu", CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB); 2170 } 2171 2172 static int param_set_sfb_size(const char *val, const struct kernel_param *kp) 2173 { 2174 int rc; 2175 unsigned long min, max; 2176 2177 if (!cpum_sf_avail()) 2178 return -ENODEV; 2179 if (!val || !strlen(val)) 2180 return -EINVAL; 2181 2182 /* Valid parameter values: "min,max" or "max" */ 2183 min = CPUM_SF_MIN_SDB; 2184 max = CPUM_SF_MAX_SDB; 2185 if (strchr(val, ',')) 2186 rc = (sscanf(val, "%lu,%lu", &min, &max) == 2) ? 0 : -EINVAL; 2187 else 2188 rc = kstrtoul(val, 10, &max); 2189 2190 if (min < 2 || min >= max || max > get_num_physpages()) 2191 rc = -EINVAL; 2192 if (rc) 2193 return rc; 2194 2195 sfb_set_limits(min, max); 2196 pr_info("The sampling buffer limits have changed to: " 2197 "min %lu max %lu (diag %lu)\n", 2198 CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB, CPUM_SF_SDB_DIAG_FACTOR); 2199 return 0; 2200 } 2201 2202 #define param_check_sfb_size(name, p) __param_check(name, p, void) 2203 static const struct kernel_param_ops param_ops_sfb_size = { 2204 .set = param_set_sfb_size, 2205 .get = param_get_sfb_size, 2206 }; 2207 2208 #define RS_INIT_FAILURE_QSI 0x0001 2209 #define RS_INIT_FAILURE_BSDES 0x0002 2210 #define RS_INIT_FAILURE_ALRT 0x0003 2211 #define RS_INIT_FAILURE_PERF 0x0004 2212 static void __init pr_cpumsf_err(unsigned int reason) 2213 { 2214 pr_err("Sampling facility support for perf is not available: " 2215 "reason %#x\n", reason); 2216 } 2217 2218 static int __init init_cpum_sampling_pmu(void) 2219 { 2220 struct hws_qsi_info_block si; 2221 int err; 2222 2223 if (!cpum_sf_avail()) 2224 return -ENODEV; 2225 2226 memset(&si, 0, sizeof(si)); 2227 if (qsi(&si)) { 2228 pr_cpumsf_err(RS_INIT_FAILURE_QSI); 2229 return -ENODEV; 2230 } 2231 2232 if (!si.as && !si.ad) 2233 return -ENODEV; 2234 2235 if (si.bsdes != sizeof(struct hws_basic_entry)) { 2236 pr_cpumsf_err(RS_INIT_FAILURE_BSDES); 2237 return -EINVAL; 2238 } 2239 2240 if (si.ad) { 2241 sfb_set_limits(CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB); 2242 /* Sampling of diagnostic data authorized, 2243 * install event into attribute list of PMU device. 2244 */ 2245 cpumsf_pmu_events_attr[SF_CYCLES_BASIC_DIAG_ATTR_IDX] = 2246 CPUMF_EVENT_PTR(SF, SF_CYCLES_BASIC_DIAG); 2247 } 2248 2249 sfdbg = debug_register(KMSG_COMPONENT, 2, 1, 80); 2250 if (!sfdbg) { 2251 pr_err("Registering for s390dbf failed\n"); 2252 return -ENOMEM; 2253 } 2254 debug_register_view(sfdbg, &debug_sprintf_view); 2255 2256 err = register_external_irq(EXT_IRQ_MEASURE_ALERT, 2257 cpumf_measurement_alert); 2258 if (err) { 2259 pr_cpumsf_err(RS_INIT_FAILURE_ALRT); 2260 debug_unregister(sfdbg); 2261 goto out; 2262 } 2263 2264 err = perf_pmu_register(&cpumf_sampling, "cpum_sf", PERF_TYPE_RAW); 2265 if (err) { 2266 pr_cpumsf_err(RS_INIT_FAILURE_PERF); 2267 unregister_external_irq(EXT_IRQ_MEASURE_ALERT, 2268 cpumf_measurement_alert); 2269 debug_unregister(sfdbg); 2270 goto out; 2271 } 2272 2273 cpuhp_setup_state(CPUHP_AP_PERF_S390_SF_ONLINE, "perf/s390/sf:online", 2274 s390_pmu_sf_online_cpu, s390_pmu_sf_offline_cpu); 2275 out: 2276 return err; 2277 } 2278 2279 arch_initcall(init_cpum_sampling_pmu); 2280 core_param(cpum_sfb_size, CPUM_SF_MAX_SDB, sfb_size, 0644); 2281