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; 338 unsigned long flags; 339 struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); 340 341 spin_lock_irqsave(&drvdata->spinlock, flags); 342 if (drvdata->reading) { 343 spin_unlock_irqrestore(&drvdata->spinlock, flags); 344 return -EBUSY; 345 } 346 347 ret = tmc_etf_enable_hw(drvdata); 348 if (!ret) 349 drvdata->mode = CS_MODE_SYSFS; 350 spin_unlock_irqrestore(&drvdata->spinlock, flags); 351 352 if (!ret) 353 dev_dbg(&csdev->dev, "TMC-ETF enabled\n"); 354 return ret; 355 } 356 357 static void tmc_disable_etf_link(struct coresight_device *csdev, 358 int inport, int outport) 359 { 360 unsigned long flags; 361 struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); 362 363 spin_lock_irqsave(&drvdata->spinlock, flags); 364 if (drvdata->reading) { 365 spin_unlock_irqrestore(&drvdata->spinlock, flags); 366 return; 367 } 368 369 tmc_etf_disable_hw(drvdata); 370 drvdata->mode = CS_MODE_DISABLED; 371 spin_unlock_irqrestore(&drvdata->spinlock, flags); 372 373 dev_dbg(&csdev->dev, "TMC-ETF disabled\n"); 374 } 375 376 static void *tmc_alloc_etf_buffer(struct coresight_device *csdev, 377 struct perf_event *event, void **pages, 378 int nr_pages, bool overwrite) 379 { 380 int node; 381 struct cs_buffers *buf; 382 383 node = (event->cpu == -1) ? NUMA_NO_NODE : cpu_to_node(event->cpu); 384 385 /* Allocate memory structure for interaction with Perf */ 386 buf = kzalloc_node(sizeof(struct cs_buffers), GFP_KERNEL, node); 387 if (!buf) 388 return NULL; 389 390 buf->snapshot = overwrite; 391 buf->nr_pages = nr_pages; 392 buf->data_pages = pages; 393 394 return buf; 395 } 396 397 static void tmc_free_etf_buffer(void *config) 398 { 399 struct cs_buffers *buf = config; 400 401 kfree(buf); 402 } 403 404 static int tmc_set_etf_buffer(struct coresight_device *csdev, 405 struct perf_output_handle *handle) 406 { 407 int ret = 0; 408 unsigned long head; 409 struct cs_buffers *buf = etm_perf_sink_config(handle); 410 411 if (!buf) 412 return -EINVAL; 413 414 /* wrap head around to the amount of space we have */ 415 head = handle->head & ((buf->nr_pages << PAGE_SHIFT) - 1); 416 417 /* find the page to write to */ 418 buf->cur = head / PAGE_SIZE; 419 420 /* and offset within that page */ 421 buf->offset = head % PAGE_SIZE; 422 423 local_set(&buf->data_size, 0); 424 425 return ret; 426 } 427 428 static unsigned long tmc_update_etf_buffer(struct coresight_device *csdev, 429 struct perf_output_handle *handle, 430 void *sink_config) 431 { 432 bool lost = false; 433 int i, cur; 434 const u32 *barrier; 435 u32 *buf_ptr; 436 u64 read_ptr, write_ptr; 437 u32 status; 438 unsigned long offset, to_read = 0, flags; 439 struct cs_buffers *buf = sink_config; 440 struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); 441 442 if (!buf) 443 return 0; 444 445 /* This shouldn't happen */ 446 if (WARN_ON_ONCE(drvdata->mode != CS_MODE_PERF)) 447 return 0; 448 449 spin_lock_irqsave(&drvdata->spinlock, flags); 450 451 /* Don't do anything if another tracer is using this sink */ 452 if (atomic_read(csdev->refcnt) != 1) 453 goto out; 454 455 CS_UNLOCK(drvdata->base); 456 457 tmc_flush_and_stop(drvdata); 458 459 read_ptr = tmc_read_rrp(drvdata); 460 write_ptr = tmc_read_rwp(drvdata); 461 462 /* 463 * Get a hold of the status register and see if a wrap around 464 * has occurred. If so adjust things accordingly. 465 */ 466 status = readl_relaxed(drvdata->base + TMC_STS); 467 if (status & TMC_STS_FULL) { 468 lost = true; 469 to_read = drvdata->size; 470 } else { 471 to_read = CIRC_CNT(write_ptr, read_ptr, drvdata->size); 472 } 473 474 /* 475 * The TMC RAM buffer may be bigger than the space available in the 476 * perf ring buffer (handle->size). If so advance the RRP so that we 477 * get the latest trace data. In snapshot mode none of that matters 478 * since we are expected to clobber stale data in favour of the latest 479 * traces. 480 */ 481 if (!buf->snapshot && to_read > handle->size) { 482 u32 mask = tmc_get_memwidth_mask(drvdata); 483 484 /* 485 * Make sure the new size is aligned in accordance with the 486 * requirement explained in function tmc_get_memwidth_mask(). 487 */ 488 to_read = handle->size & mask; 489 /* Move the RAM read pointer up */ 490 read_ptr = (write_ptr + drvdata->size) - to_read; 491 /* Make sure we are still within our limits */ 492 if (read_ptr > (drvdata->size - 1)) 493 read_ptr -= drvdata->size; 494 /* Tell the HW */ 495 tmc_write_rrp(drvdata, read_ptr); 496 lost = true; 497 } 498 499 /* 500 * Don't set the TRUNCATED flag in snapshot mode because 1) the 501 * captured buffer is expected to be truncated and 2) a full buffer 502 * prevents the event from being re-enabled by the perf core, 503 * resulting in stale data being send to user space. 504 */ 505 if (!buf->snapshot && lost) 506 perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED); 507 508 cur = buf->cur; 509 offset = buf->offset; 510 barrier = barrier_pkt; 511 512 /* for every byte to read */ 513 for (i = 0; i < to_read; i += 4) { 514 buf_ptr = buf->data_pages[cur] + offset; 515 *buf_ptr = readl_relaxed(drvdata->base + TMC_RRD); 516 517 if (lost && *barrier) { 518 *buf_ptr = *barrier; 519 barrier++; 520 } 521 522 offset += 4; 523 if (offset >= PAGE_SIZE) { 524 offset = 0; 525 cur++; 526 /* wrap around at the end of the buffer */ 527 cur &= buf->nr_pages - 1; 528 } 529 } 530 531 /* 532 * In snapshot mode we simply increment the head by the number of byte 533 * that were written. User space function cs_etm_find_snapshot() will 534 * figure out how many bytes to get from the AUX buffer based on the 535 * position of the head. 536 */ 537 if (buf->snapshot) 538 handle->head += to_read; 539 540 CS_LOCK(drvdata->base); 541 out: 542 spin_unlock_irqrestore(&drvdata->spinlock, flags); 543 544 return to_read; 545 } 546 547 static const struct coresight_ops_sink tmc_etf_sink_ops = { 548 .enable = tmc_enable_etf_sink, 549 .disable = tmc_disable_etf_sink, 550 .alloc_buffer = tmc_alloc_etf_buffer, 551 .free_buffer = tmc_free_etf_buffer, 552 .update_buffer = tmc_update_etf_buffer, 553 }; 554 555 static const struct coresight_ops_link tmc_etf_link_ops = { 556 .enable = tmc_enable_etf_link, 557 .disable = tmc_disable_etf_link, 558 }; 559 560 const struct coresight_ops tmc_etb_cs_ops = { 561 .sink_ops = &tmc_etf_sink_ops, 562 }; 563 564 const struct coresight_ops tmc_etf_cs_ops = { 565 .sink_ops = &tmc_etf_sink_ops, 566 .link_ops = &tmc_etf_link_ops, 567 }; 568 569 int tmc_read_prepare_etb(struct tmc_drvdata *drvdata) 570 { 571 enum tmc_mode mode; 572 int ret = 0; 573 unsigned long flags; 574 575 /* config types are set a boot time and never change */ 576 if (WARN_ON_ONCE(drvdata->config_type != TMC_CONFIG_TYPE_ETB && 577 drvdata->config_type != TMC_CONFIG_TYPE_ETF)) 578 return -EINVAL; 579 580 spin_lock_irqsave(&drvdata->spinlock, flags); 581 582 if (drvdata->reading) { 583 ret = -EBUSY; 584 goto out; 585 } 586 587 /* There is no point in reading a TMC in HW FIFO mode */ 588 mode = readl_relaxed(drvdata->base + TMC_MODE); 589 if (mode != TMC_MODE_CIRCULAR_BUFFER) { 590 ret = -EINVAL; 591 goto out; 592 } 593 594 /* Don't interfere if operated from Perf */ 595 if (drvdata->mode == CS_MODE_PERF) { 596 ret = -EINVAL; 597 goto out; 598 } 599 600 /* If drvdata::buf is NULL the trace data has been read already */ 601 if (drvdata->buf == NULL) { 602 ret = -EINVAL; 603 goto out; 604 } 605 606 /* Disable the TMC if need be */ 607 if (drvdata->mode == CS_MODE_SYSFS) 608 __tmc_etb_disable_hw(drvdata); 609 610 drvdata->reading = true; 611 out: 612 spin_unlock_irqrestore(&drvdata->spinlock, flags); 613 614 return ret; 615 } 616 617 int tmc_read_unprepare_etb(struct tmc_drvdata *drvdata) 618 { 619 char *buf = NULL; 620 enum tmc_mode mode; 621 unsigned long flags; 622 623 /* config types are set a boot time and never change */ 624 if (WARN_ON_ONCE(drvdata->config_type != TMC_CONFIG_TYPE_ETB && 625 drvdata->config_type != TMC_CONFIG_TYPE_ETF)) 626 return -EINVAL; 627 628 spin_lock_irqsave(&drvdata->spinlock, flags); 629 630 /* There is no point in reading a TMC in HW FIFO mode */ 631 mode = readl_relaxed(drvdata->base + TMC_MODE); 632 if (mode != TMC_MODE_CIRCULAR_BUFFER) { 633 spin_unlock_irqrestore(&drvdata->spinlock, flags); 634 return -EINVAL; 635 } 636 637 /* Re-enable the TMC if need be */ 638 if (drvdata->mode == CS_MODE_SYSFS) { 639 /* 640 * The trace run will continue with the same allocated trace 641 * buffer. As such zero-out the buffer so that we don't end 642 * up with stale data. 643 * 644 * Since the tracer is still enabled drvdata::buf 645 * can't be NULL. 646 */ 647 memset(drvdata->buf, 0, drvdata->size); 648 __tmc_etb_enable_hw(drvdata); 649 } else { 650 /* 651 * The ETB/ETF is not tracing and the buffer was just read. 652 * As such prepare to free the trace buffer. 653 */ 654 buf = drvdata->buf; 655 drvdata->buf = NULL; 656 } 657 658 drvdata->reading = false; 659 spin_unlock_irqrestore(&drvdata->spinlock, flags); 660 661 /* 662 * Free allocated memory outside of the spinlock. There is no need 663 * to assert the validity of 'buf' since calling kfree(NULL) is safe. 664 */ 665 kfree(buf); 666 667 return 0; 668 } 669