1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright(C) 2016 Linaro Limited. All rights reserved. 4 * Author: Mathieu Poirier <mathieu.poirier@linaro.org> 5 */ 6 7 #include <linux/atomic.h> 8 #include <linux/circ_buf.h> 9 #include <linux/coresight.h> 10 #include <linux/perf_event.h> 11 #include <linux/slab.h> 12 #include "coresight-priv.h" 13 #include "coresight-tmc.h" 14 #include "coresight-etm-perf.h" 15 16 static int tmc_set_etf_buffer(struct coresight_device *csdev, 17 struct perf_output_handle *handle); 18 19 static void __tmc_etb_enable_hw(struct tmc_drvdata *drvdata) 20 { 21 CS_UNLOCK(drvdata->base); 22 23 /* Wait for TMCSReady bit to be set */ 24 tmc_wait_for_tmcready(drvdata); 25 26 writel_relaxed(TMC_MODE_CIRCULAR_BUFFER, drvdata->base + TMC_MODE); 27 writel_relaxed(TMC_FFCR_EN_FMT | TMC_FFCR_EN_TI | 28 TMC_FFCR_FON_FLIN | TMC_FFCR_FON_TRIG_EVT | 29 TMC_FFCR_TRIGON_TRIGIN, 30 drvdata->base + TMC_FFCR); 31 32 writel_relaxed(drvdata->trigger_cntr, drvdata->base + TMC_TRG); 33 tmc_enable_hw(drvdata); 34 35 CS_LOCK(drvdata->base); 36 } 37 38 static int tmc_etb_enable_hw(struct tmc_drvdata *drvdata) 39 { 40 int rc = coresight_claim_device(drvdata->base); 41 42 if (rc) 43 return rc; 44 45 __tmc_etb_enable_hw(drvdata); 46 return 0; 47 } 48 49 static void tmc_etb_dump_hw(struct tmc_drvdata *drvdata) 50 { 51 char *bufp; 52 u32 read_data, lost; 53 54 /* Check if the buffer wrapped around. */ 55 lost = readl_relaxed(drvdata->base + TMC_STS) & TMC_STS_FULL; 56 bufp = drvdata->buf; 57 drvdata->len = 0; 58 while (1) { 59 read_data = readl_relaxed(drvdata->base + TMC_RRD); 60 if (read_data == 0xFFFFFFFF) 61 break; 62 memcpy(bufp, &read_data, 4); 63 bufp += 4; 64 drvdata->len += 4; 65 } 66 67 if (lost) 68 coresight_insert_barrier_packet(drvdata->buf); 69 return; 70 } 71 72 static void __tmc_etb_disable_hw(struct tmc_drvdata *drvdata) 73 { 74 CS_UNLOCK(drvdata->base); 75 76 tmc_flush_and_stop(drvdata); 77 /* 78 * When operating in sysFS mode the content of the buffer needs to be 79 * read before the TMC is disabled. 80 */ 81 if (drvdata->mode == CS_MODE_SYSFS) 82 tmc_etb_dump_hw(drvdata); 83 tmc_disable_hw(drvdata); 84 85 CS_LOCK(drvdata->base); 86 } 87 88 static void tmc_etb_disable_hw(struct tmc_drvdata *drvdata) 89 { 90 __tmc_etb_disable_hw(drvdata); 91 coresight_disclaim_device(drvdata->base); 92 } 93 94 static void __tmc_etf_enable_hw(struct tmc_drvdata *drvdata) 95 { 96 CS_UNLOCK(drvdata->base); 97 98 /* Wait for TMCSReady bit to be set */ 99 tmc_wait_for_tmcready(drvdata); 100 101 writel_relaxed(TMC_MODE_HARDWARE_FIFO, drvdata->base + TMC_MODE); 102 writel_relaxed(TMC_FFCR_EN_FMT | TMC_FFCR_EN_TI, 103 drvdata->base + TMC_FFCR); 104 writel_relaxed(0x0, drvdata->base + TMC_BUFWM); 105 tmc_enable_hw(drvdata); 106 107 CS_LOCK(drvdata->base); 108 } 109 110 static int tmc_etf_enable_hw(struct tmc_drvdata *drvdata) 111 { 112 int rc = coresight_claim_device(drvdata->base); 113 114 if (rc) 115 return rc; 116 117 __tmc_etf_enable_hw(drvdata); 118 return 0; 119 } 120 121 static void tmc_etf_disable_hw(struct tmc_drvdata *drvdata) 122 { 123 CS_UNLOCK(drvdata->base); 124 125 tmc_flush_and_stop(drvdata); 126 tmc_disable_hw(drvdata); 127 coresight_disclaim_device_unlocked(drvdata->base); 128 CS_LOCK(drvdata->base); 129 } 130 131 /* 132 * Return the available trace data in the buffer from @pos, with 133 * a maximum limit of @len, updating the @bufpp on where to 134 * find it. 135 */ 136 ssize_t tmc_etb_get_sysfs_trace(struct tmc_drvdata *drvdata, 137 loff_t pos, size_t len, char **bufpp) 138 { 139 ssize_t actual = len; 140 141 /* Adjust the len to available size @pos */ 142 if (pos + actual > drvdata->len) 143 actual = drvdata->len - pos; 144 if (actual > 0) 145 *bufpp = drvdata->buf + pos; 146 return actual; 147 } 148 149 static int tmc_enable_etf_sink_sysfs(struct coresight_device *csdev) 150 { 151 int ret = 0; 152 bool used = false; 153 char *buf = NULL; 154 unsigned long flags; 155 struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); 156 157 /* 158 * If we don't have a buffer release the lock and allocate memory. 159 * Otherwise keep the lock and move along. 160 */ 161 spin_lock_irqsave(&drvdata->spinlock, flags); 162 if (!drvdata->buf) { 163 spin_unlock_irqrestore(&drvdata->spinlock, flags); 164 165 /* Allocating the memory here while outside of the spinlock */ 166 buf = kzalloc(drvdata->size, GFP_KERNEL); 167 if (!buf) 168 return -ENOMEM; 169 170 /* Let's try again */ 171 spin_lock_irqsave(&drvdata->spinlock, flags); 172 } 173 174 if (drvdata->reading) { 175 ret = -EBUSY; 176 goto out; 177 } 178 179 /* 180 * In sysFS mode we can have multiple writers per sink. Since this 181 * sink is already enabled no memory is needed and the HW need not be 182 * touched. 183 */ 184 if (drvdata->mode == CS_MODE_SYSFS) { 185 atomic_inc(csdev->refcnt); 186 goto out; 187 } 188 189 /* 190 * If drvdata::buf isn't NULL, memory was allocated for a previous 191 * trace run but wasn't read. If so simply zero-out the memory. 192 * Otherwise use the memory allocated above. 193 * 194 * The memory is freed when users read the buffer using the 195 * /dev/xyz.{etf|etb} interface. See tmc_read_unprepare_etf() for 196 * details. 197 */ 198 if (drvdata->buf) { 199 memset(drvdata->buf, 0, drvdata->size); 200 } else { 201 used = true; 202 drvdata->buf = buf; 203 } 204 205 ret = tmc_etb_enable_hw(drvdata); 206 if (!ret) { 207 drvdata->mode = CS_MODE_SYSFS; 208 atomic_inc(csdev->refcnt); 209 } else { 210 /* Free up the buffer if we failed to enable */ 211 used = false; 212 } 213 out: 214 spin_unlock_irqrestore(&drvdata->spinlock, flags); 215 216 /* Free memory outside the spinlock if need be */ 217 if (!used) 218 kfree(buf); 219 220 return ret; 221 } 222 223 static int tmc_enable_etf_sink_perf(struct coresight_device *csdev, void *data) 224 { 225 int ret = 0; 226 pid_t pid; 227 unsigned long flags; 228 struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); 229 struct perf_output_handle *handle = data; 230 231 spin_lock_irqsave(&drvdata->spinlock, flags); 232 do { 233 ret = -EINVAL; 234 if (drvdata->reading) 235 break; 236 /* 237 * No need to continue if the ETB/ETF is already operated 238 * from sysFS. 239 */ 240 if (drvdata->mode == CS_MODE_SYSFS) { 241 ret = -EBUSY; 242 break; 243 } 244 245 /* Get a handle on the pid of the process to monitor */ 246 pid = task_pid_nr(handle->event->owner); 247 248 if (drvdata->pid != -1 && drvdata->pid != pid) { 249 ret = -EBUSY; 250 break; 251 } 252 253 ret = tmc_set_etf_buffer(csdev, handle); 254 if (ret) 255 break; 256 257 /* 258 * No HW configuration is needed if the sink is already in 259 * use for this session. 260 */ 261 if (drvdata->pid == pid) { 262 atomic_inc(csdev->refcnt); 263 break; 264 } 265 266 ret = tmc_etb_enable_hw(drvdata); 267 if (!ret) { 268 /* Associate with monitored process. */ 269 drvdata->pid = pid; 270 drvdata->mode = CS_MODE_PERF; 271 atomic_inc(csdev->refcnt); 272 } 273 } while (0); 274 spin_unlock_irqrestore(&drvdata->spinlock, flags); 275 276 return ret; 277 } 278 279 static int tmc_enable_etf_sink(struct coresight_device *csdev, 280 u32 mode, void *data) 281 { 282 int ret; 283 284 switch (mode) { 285 case CS_MODE_SYSFS: 286 ret = tmc_enable_etf_sink_sysfs(csdev); 287 break; 288 case CS_MODE_PERF: 289 ret = tmc_enable_etf_sink_perf(csdev, data); 290 break; 291 /* We shouldn't be here */ 292 default: 293 ret = -EINVAL; 294 break; 295 } 296 297 if (ret) 298 return ret; 299 300 dev_dbg(&csdev->dev, "TMC-ETB/ETF enabled\n"); 301 return 0; 302 } 303 304 static int tmc_disable_etf_sink(struct coresight_device *csdev) 305 { 306 unsigned long flags; 307 struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); 308 309 spin_lock_irqsave(&drvdata->spinlock, flags); 310 311 if (drvdata->reading) { 312 spin_unlock_irqrestore(&drvdata->spinlock, flags); 313 return -EBUSY; 314 } 315 316 if (atomic_dec_return(csdev->refcnt)) { 317 spin_unlock_irqrestore(&drvdata->spinlock, flags); 318 return -EBUSY; 319 } 320 321 /* Complain if we (somehow) got out of sync */ 322 WARN_ON_ONCE(drvdata->mode == CS_MODE_DISABLED); 323 tmc_etb_disable_hw(drvdata); 324 /* Dissociate from monitored process. */ 325 drvdata->pid = -1; 326 drvdata->mode = CS_MODE_DISABLED; 327 328 spin_unlock_irqrestore(&drvdata->spinlock, flags); 329 330 dev_dbg(&csdev->dev, "TMC-ETB/ETF disabled\n"); 331 return 0; 332 } 333 334 static int tmc_enable_etf_link(struct coresight_device *csdev, 335 int inport, int outport) 336 { 337 int ret = 0; 338 unsigned long flags; 339 struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); 340 bool first_enable = false; 341 342 spin_lock_irqsave(&drvdata->spinlock, flags); 343 if (drvdata->reading) { 344 spin_unlock_irqrestore(&drvdata->spinlock, flags); 345 return -EBUSY; 346 } 347 348 if (atomic_read(&csdev->refcnt[0]) == 0) { 349 ret = tmc_etf_enable_hw(drvdata); 350 if (!ret) { 351 drvdata->mode = CS_MODE_SYSFS; 352 first_enable = true; 353 } 354 } 355 if (!ret) 356 atomic_inc(&csdev->refcnt[0]); 357 spin_unlock_irqrestore(&drvdata->spinlock, flags); 358 359 if (first_enable) 360 dev_dbg(&csdev->dev, "TMC-ETF enabled\n"); 361 return ret; 362 } 363 364 static void tmc_disable_etf_link(struct coresight_device *csdev, 365 int inport, int outport) 366 { 367 unsigned long flags; 368 struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); 369 bool last_disable = false; 370 371 spin_lock_irqsave(&drvdata->spinlock, flags); 372 if (drvdata->reading) { 373 spin_unlock_irqrestore(&drvdata->spinlock, flags); 374 return; 375 } 376 377 if (atomic_dec_return(&csdev->refcnt[0]) == 0) { 378 tmc_etf_disable_hw(drvdata); 379 drvdata->mode = CS_MODE_DISABLED; 380 last_disable = true; 381 } 382 spin_unlock_irqrestore(&drvdata->spinlock, flags); 383 384 if (last_disable) 385 dev_dbg(&csdev->dev, "TMC-ETF disabled\n"); 386 } 387 388 static void *tmc_alloc_etf_buffer(struct coresight_device *csdev, 389 struct perf_event *event, void **pages, 390 int nr_pages, bool overwrite) 391 { 392 int node; 393 struct cs_buffers *buf; 394 395 node = (event->cpu == -1) ? NUMA_NO_NODE : cpu_to_node(event->cpu); 396 397 /* Allocate memory structure for interaction with Perf */ 398 buf = kzalloc_node(sizeof(struct cs_buffers), GFP_KERNEL, node); 399 if (!buf) 400 return NULL; 401 402 buf->snapshot = overwrite; 403 buf->nr_pages = nr_pages; 404 buf->data_pages = pages; 405 406 return buf; 407 } 408 409 static void tmc_free_etf_buffer(void *config) 410 { 411 struct cs_buffers *buf = config; 412 413 kfree(buf); 414 } 415 416 static int tmc_set_etf_buffer(struct coresight_device *csdev, 417 struct perf_output_handle *handle) 418 { 419 int ret = 0; 420 unsigned long head; 421 struct cs_buffers *buf = etm_perf_sink_config(handle); 422 423 if (!buf) 424 return -EINVAL; 425 426 /* wrap head around to the amount of space we have */ 427 head = handle->head & ((buf->nr_pages << PAGE_SHIFT) - 1); 428 429 /* find the page to write to */ 430 buf->cur = head / PAGE_SIZE; 431 432 /* and offset within that page */ 433 buf->offset = head % PAGE_SIZE; 434 435 local_set(&buf->data_size, 0); 436 437 return ret; 438 } 439 440 static unsigned long tmc_update_etf_buffer(struct coresight_device *csdev, 441 struct perf_output_handle *handle, 442 void *sink_config) 443 { 444 bool lost = false; 445 int i, cur; 446 const u32 *barrier; 447 u32 *buf_ptr; 448 u64 read_ptr, write_ptr; 449 u32 status; 450 unsigned long offset, to_read = 0, flags; 451 struct cs_buffers *buf = sink_config; 452 struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); 453 454 if (!buf) 455 return 0; 456 457 /* This shouldn't happen */ 458 if (WARN_ON_ONCE(drvdata->mode != CS_MODE_PERF)) 459 return 0; 460 461 spin_lock_irqsave(&drvdata->spinlock, flags); 462 463 /* Don't do anything if another tracer is using this sink */ 464 if (atomic_read(csdev->refcnt) != 1) 465 goto out; 466 467 CS_UNLOCK(drvdata->base); 468 469 tmc_flush_and_stop(drvdata); 470 471 read_ptr = tmc_read_rrp(drvdata); 472 write_ptr = tmc_read_rwp(drvdata); 473 474 /* 475 * Get a hold of the status register and see if a wrap around 476 * has occurred. If so adjust things accordingly. 477 */ 478 status = readl_relaxed(drvdata->base + TMC_STS); 479 if (status & TMC_STS_FULL) { 480 lost = true; 481 to_read = drvdata->size; 482 } else { 483 to_read = CIRC_CNT(write_ptr, read_ptr, drvdata->size); 484 } 485 486 /* 487 * The TMC RAM buffer may be bigger than the space available in the 488 * perf ring buffer (handle->size). If so advance the RRP so that we 489 * get the latest trace data. In snapshot mode none of that matters 490 * since we are expected to clobber stale data in favour of the latest 491 * traces. 492 */ 493 if (!buf->snapshot && to_read > handle->size) { 494 u32 mask = tmc_get_memwidth_mask(drvdata); 495 496 /* 497 * Make sure the new size is aligned in accordance with the 498 * requirement explained in function tmc_get_memwidth_mask(). 499 */ 500 to_read = handle->size & mask; 501 /* Move the RAM read pointer up */ 502 read_ptr = (write_ptr + drvdata->size) - to_read; 503 /* Make sure we are still within our limits */ 504 if (read_ptr > (drvdata->size - 1)) 505 read_ptr -= drvdata->size; 506 /* Tell the HW */ 507 tmc_write_rrp(drvdata, read_ptr); 508 lost = true; 509 } 510 511 /* 512 * Don't set the TRUNCATED flag in snapshot mode because 1) the 513 * captured buffer is expected to be truncated and 2) a full buffer 514 * prevents the event from being re-enabled by the perf core, 515 * resulting in stale data being send to user space. 516 */ 517 if (!buf->snapshot && lost) 518 perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED); 519 520 cur = buf->cur; 521 offset = buf->offset; 522 barrier = barrier_pkt; 523 524 /* for every byte to read */ 525 for (i = 0; i < to_read; i += 4) { 526 buf_ptr = buf->data_pages[cur] + offset; 527 *buf_ptr = readl_relaxed(drvdata->base + TMC_RRD); 528 529 if (lost && *barrier) { 530 *buf_ptr = *barrier; 531 barrier++; 532 } 533 534 offset += 4; 535 if (offset >= PAGE_SIZE) { 536 offset = 0; 537 cur++; 538 /* wrap around at the end of the buffer */ 539 cur &= buf->nr_pages - 1; 540 } 541 } 542 543 /* 544 * In snapshot mode we simply increment the head by the number of byte 545 * that were written. User space function cs_etm_find_snapshot() will 546 * figure out how many bytes to get from the AUX buffer based on the 547 * position of the head. 548 */ 549 if (buf->snapshot) 550 handle->head += to_read; 551 552 CS_LOCK(drvdata->base); 553 out: 554 spin_unlock_irqrestore(&drvdata->spinlock, flags); 555 556 return to_read; 557 } 558 559 static const struct coresight_ops_sink tmc_etf_sink_ops = { 560 .enable = tmc_enable_etf_sink, 561 .disable = tmc_disable_etf_sink, 562 .alloc_buffer = tmc_alloc_etf_buffer, 563 .free_buffer = tmc_free_etf_buffer, 564 .update_buffer = tmc_update_etf_buffer, 565 }; 566 567 static const struct coresight_ops_link tmc_etf_link_ops = { 568 .enable = tmc_enable_etf_link, 569 .disable = tmc_disable_etf_link, 570 }; 571 572 const struct coresight_ops tmc_etb_cs_ops = { 573 .sink_ops = &tmc_etf_sink_ops, 574 }; 575 576 const struct coresight_ops tmc_etf_cs_ops = { 577 .sink_ops = &tmc_etf_sink_ops, 578 .link_ops = &tmc_etf_link_ops, 579 }; 580 581 int tmc_read_prepare_etb(struct tmc_drvdata *drvdata) 582 { 583 enum tmc_mode mode; 584 int ret = 0; 585 unsigned long flags; 586 587 /* config types are set a boot time and never change */ 588 if (WARN_ON_ONCE(drvdata->config_type != TMC_CONFIG_TYPE_ETB && 589 drvdata->config_type != TMC_CONFIG_TYPE_ETF)) 590 return -EINVAL; 591 592 spin_lock_irqsave(&drvdata->spinlock, flags); 593 594 if (drvdata->reading) { 595 ret = -EBUSY; 596 goto out; 597 } 598 599 /* Don't interfere if operated from Perf */ 600 if (drvdata->mode == CS_MODE_PERF) { 601 ret = -EINVAL; 602 goto out; 603 } 604 605 /* If drvdata::buf is NULL the trace data has been read already */ 606 if (drvdata->buf == NULL) { 607 ret = -EINVAL; 608 goto out; 609 } 610 611 /* Disable the TMC if need be */ 612 if (drvdata->mode == CS_MODE_SYSFS) { 613 /* There is no point in reading a TMC in HW FIFO mode */ 614 mode = readl_relaxed(drvdata->base + TMC_MODE); 615 if (mode != TMC_MODE_CIRCULAR_BUFFER) { 616 ret = -EINVAL; 617 goto out; 618 } 619 __tmc_etb_disable_hw(drvdata); 620 } 621 622 drvdata->reading = true; 623 out: 624 spin_unlock_irqrestore(&drvdata->spinlock, flags); 625 626 return ret; 627 } 628 629 int tmc_read_unprepare_etb(struct tmc_drvdata *drvdata) 630 { 631 char *buf = NULL; 632 enum tmc_mode mode; 633 unsigned long flags; 634 635 /* config types are set a boot time and never change */ 636 if (WARN_ON_ONCE(drvdata->config_type != TMC_CONFIG_TYPE_ETB && 637 drvdata->config_type != TMC_CONFIG_TYPE_ETF)) 638 return -EINVAL; 639 640 spin_lock_irqsave(&drvdata->spinlock, flags); 641 642 /* Re-enable the TMC if need be */ 643 if (drvdata->mode == CS_MODE_SYSFS) { 644 /* There is no point in reading a TMC in HW FIFO mode */ 645 mode = readl_relaxed(drvdata->base + TMC_MODE); 646 if (mode != TMC_MODE_CIRCULAR_BUFFER) { 647 spin_unlock_irqrestore(&drvdata->spinlock, flags); 648 return -EINVAL; 649 } 650 /* 651 * The trace run will continue with the same allocated trace 652 * buffer. As such zero-out the buffer so that we don't end 653 * up with stale data. 654 * 655 * Since the tracer is still enabled drvdata::buf 656 * can't be NULL. 657 */ 658 memset(drvdata->buf, 0, drvdata->size); 659 __tmc_etb_enable_hw(drvdata); 660 } else { 661 /* 662 * The ETB/ETF is not tracing and the buffer was just read. 663 * As such prepare to free the trace buffer. 664 */ 665 buf = drvdata->buf; 666 drvdata->buf = NULL; 667 } 668 669 drvdata->reading = false; 670 spin_unlock_irqrestore(&drvdata->spinlock, flags); 671 672 /* 673 * Free allocated memory outside of the spinlock. There is no need 674 * to assert the validity of 'buf' since calling kfree(NULL) is safe. 675 */ 676 kfree(buf); 677 678 return 0; 679 } 680