1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright(C) 2015 Linaro Limited. All rights reserved.
4  * Author: Mathieu Poirier <mathieu.poirier@linaro.org>
5  */
6 
7 #include <linux/coresight.h>
8 #include <linux/coresight-pmu.h>
9 #include <linux/cpumask.h>
10 #include <linux/device.h>
11 #include <linux/list.h>
12 #include <linux/mm.h>
13 #include <linux/init.h>
14 #include <linux/perf_event.h>
15 #include <linux/percpu-defs.h>
16 #include <linux/slab.h>
17 #include <linux/stringhash.h>
18 #include <linux/types.h>
19 #include <linux/workqueue.h>
20 
21 #include "coresight-etm-perf.h"
22 #include "coresight-priv.h"
23 
24 static struct pmu etm_pmu;
25 static bool etm_perf_up;
26 
27 static DEFINE_PER_CPU(struct perf_output_handle, ctx_handle);
28 static DEFINE_PER_CPU(struct coresight_device *, csdev_src);
29 
30 /* ETMv3.5/PTM's ETMCR is 'config' */
31 PMU_FORMAT_ATTR(cycacc,		"config:" __stringify(ETM_OPT_CYCACC));
32 PMU_FORMAT_ATTR(contextid,	"config:" __stringify(ETM_OPT_CTXTID));
33 PMU_FORMAT_ATTR(timestamp,	"config:" __stringify(ETM_OPT_TS));
34 PMU_FORMAT_ATTR(retstack,	"config:" __stringify(ETM_OPT_RETSTK));
35 /* Sink ID - same for all ETMs */
36 PMU_FORMAT_ATTR(sinkid,		"config2:0-31");
37 
38 static struct attribute *etm_config_formats_attr[] = {
39 	&format_attr_cycacc.attr,
40 	&format_attr_contextid.attr,
41 	&format_attr_timestamp.attr,
42 	&format_attr_retstack.attr,
43 	&format_attr_sinkid.attr,
44 	NULL,
45 };
46 
47 static const struct attribute_group etm_pmu_format_group = {
48 	.name   = "format",
49 	.attrs  = etm_config_formats_attr,
50 };
51 
52 static struct attribute *etm_config_sinks_attr[] = {
53 	NULL,
54 };
55 
56 static const struct attribute_group etm_pmu_sinks_group = {
57 	.name   = "sinks",
58 	.attrs  = etm_config_sinks_attr,
59 };
60 
61 static const struct attribute_group *etm_pmu_attr_groups[] = {
62 	&etm_pmu_format_group,
63 	&etm_pmu_sinks_group,
64 	NULL,
65 };
66 
67 static inline struct list_head **
68 etm_event_cpu_path_ptr(struct etm_event_data *data, int cpu)
69 {
70 	return per_cpu_ptr(data->path, cpu);
71 }
72 
73 static inline struct list_head *
74 etm_event_cpu_path(struct etm_event_data *data, int cpu)
75 {
76 	return *etm_event_cpu_path_ptr(data, cpu);
77 }
78 
79 static void etm_event_read(struct perf_event *event) {}
80 
81 static int etm_addr_filters_alloc(struct perf_event *event)
82 {
83 	struct etm_filters *filters;
84 	int node = event->cpu == -1 ? -1 : cpu_to_node(event->cpu);
85 
86 	filters = kzalloc_node(sizeof(struct etm_filters), GFP_KERNEL, node);
87 	if (!filters)
88 		return -ENOMEM;
89 
90 	if (event->parent)
91 		memcpy(filters, event->parent->hw.addr_filters,
92 		       sizeof(*filters));
93 
94 	event->hw.addr_filters = filters;
95 
96 	return 0;
97 }
98 
99 static void etm_event_destroy(struct perf_event *event)
100 {
101 	kfree(event->hw.addr_filters);
102 	event->hw.addr_filters = NULL;
103 }
104 
105 static int etm_event_init(struct perf_event *event)
106 {
107 	int ret = 0;
108 
109 	if (event->attr.type != etm_pmu.type) {
110 		ret = -ENOENT;
111 		goto out;
112 	}
113 
114 	ret = etm_addr_filters_alloc(event);
115 	if (ret)
116 		goto out;
117 
118 	event->destroy = etm_event_destroy;
119 out:
120 	return ret;
121 }
122 
123 static void free_sink_buffer(struct etm_event_data *event_data)
124 {
125 	int cpu;
126 	cpumask_t *mask = &event_data->mask;
127 	struct coresight_device *sink;
128 
129 	if (WARN_ON(cpumask_empty(mask)))
130 		return;
131 
132 	if (!event_data->snk_config)
133 		return;
134 
135 	cpu = cpumask_first(mask);
136 	sink = coresight_get_sink(etm_event_cpu_path(event_data, cpu));
137 	sink_ops(sink)->free_buffer(event_data->snk_config);
138 }
139 
140 static void free_event_data(struct work_struct *work)
141 {
142 	int cpu;
143 	cpumask_t *mask;
144 	struct etm_event_data *event_data;
145 
146 	event_data = container_of(work, struct etm_event_data, work);
147 	mask = &event_data->mask;
148 
149 	/* Free the sink buffers, if there are any */
150 	free_sink_buffer(event_data);
151 
152 	for_each_cpu(cpu, mask) {
153 		struct list_head **ppath;
154 
155 		ppath = etm_event_cpu_path_ptr(event_data, cpu);
156 		if (!(IS_ERR_OR_NULL(*ppath)))
157 			coresight_release_path(*ppath);
158 		*ppath = NULL;
159 	}
160 
161 	free_percpu(event_data->path);
162 	kfree(event_data);
163 }
164 
165 static void *alloc_event_data(int cpu)
166 {
167 	cpumask_t *mask;
168 	struct etm_event_data *event_data;
169 
170 	/* First get memory for the session's data */
171 	event_data = kzalloc(sizeof(struct etm_event_data), GFP_KERNEL);
172 	if (!event_data)
173 		return NULL;
174 
175 
176 	mask = &event_data->mask;
177 	if (cpu != -1)
178 		cpumask_set_cpu(cpu, mask);
179 	else
180 		cpumask_copy(mask, cpu_present_mask);
181 
182 	/*
183 	 * Each CPU has a single path between source and destination.  As such
184 	 * allocate an array using CPU numbers as indexes.  That way a path
185 	 * for any CPU can easily be accessed at any given time.  We proceed
186 	 * the same way for sessions involving a single CPU.  The cost of
187 	 * unused memory when dealing with single CPU trace scenarios is small
188 	 * compared to the cost of searching through an optimized array.
189 	 */
190 	event_data->path = alloc_percpu(struct list_head *);
191 
192 	if (!event_data->path) {
193 		kfree(event_data);
194 		return NULL;
195 	}
196 
197 	return event_data;
198 }
199 
200 static void etm_free_aux(void *data)
201 {
202 	struct etm_event_data *event_data = data;
203 
204 	schedule_work(&event_data->work);
205 }
206 
207 static void *etm_setup_aux(struct perf_event *event, void **pages,
208 			   int nr_pages, bool overwrite)
209 {
210 	u32 id;
211 	int cpu = event->cpu;
212 	cpumask_t *mask;
213 	struct coresight_device *sink;
214 	struct etm_event_data *event_data = NULL;
215 
216 	event_data = alloc_event_data(cpu);
217 	if (!event_data)
218 		return NULL;
219 	INIT_WORK(&event_data->work, free_event_data);
220 
221 	/* First get the selected sink from user space. */
222 	if (event->attr.config2) {
223 		id = (u32)event->attr.config2;
224 		sink = coresight_get_sink_by_id(id);
225 	}
226 
227 	mask = &event_data->mask;
228 
229 	/*
230 	 * Setup the path for each CPU in a trace session. We try to build
231 	 * trace path for each CPU in the mask. If we don't find an ETM
232 	 * for the CPU or fail to build a path, we clear the CPU from the
233 	 * mask and continue with the rest. If ever we try to trace on those
234 	 * CPUs, we can handle it and fail the session.
235 	 */
236 	for_each_cpu(cpu, mask) {
237 		struct list_head *path;
238 		struct coresight_device *csdev;
239 
240 		csdev = per_cpu(csdev_src, cpu);
241 		/*
242 		 * If there is no ETM associated with this CPU clear it from
243 		 * the mask and continue with the rest. If ever we try to trace
244 		 * on this CPU, we handle it accordingly.
245 		 */
246 		if (!csdev) {
247 			cpumask_clear_cpu(cpu, mask);
248 			continue;
249 		}
250 
251 		/*
252 		 * No sink provided - look for a default sink for one of the
253 		 * devices. At present we only support topology where all CPUs
254 		 * use the same sink [N:1], so only need to find one sink. The
255 		 * coresight_build_path later will remove any CPU that does not
256 		 * attach to the sink, or if we have not found a sink.
257 		 */
258 		if (!sink)
259 			sink = coresight_find_default_sink(csdev);
260 
261 		/*
262 		 * Building a path doesn't enable it, it simply builds a
263 		 * list of devices from source to sink that can be
264 		 * referenced later when the path is actually needed.
265 		 */
266 		path = coresight_build_path(csdev, sink);
267 		if (IS_ERR(path)) {
268 			cpumask_clear_cpu(cpu, mask);
269 			continue;
270 		}
271 
272 		*etm_event_cpu_path_ptr(event_data, cpu) = path;
273 	}
274 
275 	/* no sink found for any CPU - cannot trace */
276 	if (!sink)
277 		goto err;
278 
279 	/* If we don't have any CPUs ready for tracing, abort */
280 	cpu = cpumask_first(mask);
281 	if (cpu >= nr_cpu_ids)
282 		goto err;
283 
284 	if (!sink_ops(sink)->alloc_buffer || !sink_ops(sink)->free_buffer)
285 		goto err;
286 
287 	/* Allocate the sink buffer for this session */
288 	event_data->snk_config =
289 			sink_ops(sink)->alloc_buffer(sink, event, pages,
290 						     nr_pages, overwrite);
291 	if (!event_data->snk_config)
292 		goto err;
293 
294 out:
295 	return event_data;
296 
297 err:
298 	etm_free_aux(event_data);
299 	event_data = NULL;
300 	goto out;
301 }
302 
303 static void etm_event_start(struct perf_event *event, int flags)
304 {
305 	int cpu = smp_processor_id();
306 	struct etm_event_data *event_data;
307 	struct perf_output_handle *handle = this_cpu_ptr(&ctx_handle);
308 	struct coresight_device *sink, *csdev = per_cpu(csdev_src, cpu);
309 	struct list_head *path;
310 
311 	if (!csdev)
312 		goto fail;
313 
314 	/*
315 	 * Deal with the ring buffer API and get a handle on the
316 	 * session's information.
317 	 */
318 	event_data = perf_aux_output_begin(handle, event);
319 	if (!event_data)
320 		goto fail;
321 
322 	/*
323 	 * Check if this ETM is allowed to trace, as decided
324 	 * at etm_setup_aux(). This could be due to an unreachable
325 	 * sink from this ETM. We can't do much in this case if
326 	 * the sink was specified or hinted to the driver. For
327 	 * now, simply don't record anything on this ETM.
328 	 */
329 	if (!cpumask_test_cpu(cpu, &event_data->mask))
330 		goto fail_end_stop;
331 
332 	path = etm_event_cpu_path(event_data, cpu);
333 	/* We need a sink, no need to continue without one */
334 	sink = coresight_get_sink(path);
335 	if (WARN_ON_ONCE(!sink))
336 		goto fail_end_stop;
337 
338 	/* Nothing will happen without a path */
339 	if (coresight_enable_path(path, CS_MODE_PERF, handle))
340 		goto fail_end_stop;
341 
342 	/* Tell the perf core the event is alive */
343 	event->hw.state = 0;
344 
345 	/* Finally enable the tracer */
346 	if (source_ops(csdev)->enable(csdev, event, CS_MODE_PERF))
347 		goto fail_disable_path;
348 
349 out:
350 	return;
351 
352 fail_disable_path:
353 	coresight_disable_path(path);
354 fail_end_stop:
355 	perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
356 	perf_aux_output_end(handle, 0);
357 fail:
358 	event->hw.state = PERF_HES_STOPPED;
359 	goto out;
360 }
361 
362 static void etm_event_stop(struct perf_event *event, int mode)
363 {
364 	int cpu = smp_processor_id();
365 	unsigned long size;
366 	struct coresight_device *sink, *csdev = per_cpu(csdev_src, cpu);
367 	struct perf_output_handle *handle = this_cpu_ptr(&ctx_handle);
368 	struct etm_event_data *event_data = perf_get_aux(handle);
369 	struct list_head *path;
370 
371 	if (event->hw.state == PERF_HES_STOPPED)
372 		return;
373 
374 	if (!csdev)
375 		return;
376 
377 	path = etm_event_cpu_path(event_data, cpu);
378 	if (!path)
379 		return;
380 
381 	sink = coresight_get_sink(path);
382 	if (!sink)
383 		return;
384 
385 	/* stop tracer */
386 	source_ops(csdev)->disable(csdev, event);
387 
388 	/* tell the core */
389 	event->hw.state = PERF_HES_STOPPED;
390 
391 	if (mode & PERF_EF_UPDATE) {
392 		if (WARN_ON_ONCE(handle->event != event))
393 			return;
394 
395 		/* update trace information */
396 		if (!sink_ops(sink)->update_buffer)
397 			return;
398 
399 		size = sink_ops(sink)->update_buffer(sink, handle,
400 					      event_data->snk_config);
401 		perf_aux_output_end(handle, size);
402 	}
403 
404 	/* Disabling the path make its elements available to other sessions */
405 	coresight_disable_path(path);
406 }
407 
408 static int etm_event_add(struct perf_event *event, int mode)
409 {
410 	int ret = 0;
411 	struct hw_perf_event *hwc = &event->hw;
412 
413 	if (mode & PERF_EF_START) {
414 		etm_event_start(event, 0);
415 		if (hwc->state & PERF_HES_STOPPED)
416 			ret = -EINVAL;
417 	} else {
418 		hwc->state = PERF_HES_STOPPED;
419 	}
420 
421 	return ret;
422 }
423 
424 static void etm_event_del(struct perf_event *event, int mode)
425 {
426 	etm_event_stop(event, PERF_EF_UPDATE);
427 }
428 
429 static int etm_addr_filters_validate(struct list_head *filters)
430 {
431 	bool range = false, address = false;
432 	int index = 0;
433 	struct perf_addr_filter *filter;
434 
435 	list_for_each_entry(filter, filters, entry) {
436 		/*
437 		 * No need to go further if there's no more
438 		 * room for filters.
439 		 */
440 		if (++index > ETM_ADDR_CMP_MAX)
441 			return -EOPNOTSUPP;
442 
443 		/* filter::size==0 means single address trigger */
444 		if (filter->size) {
445 			/*
446 			 * The existing code relies on START/STOP filters
447 			 * being address filters.
448 			 */
449 			if (filter->action == PERF_ADDR_FILTER_ACTION_START ||
450 			    filter->action == PERF_ADDR_FILTER_ACTION_STOP)
451 				return -EOPNOTSUPP;
452 
453 			range = true;
454 		} else
455 			address = true;
456 
457 		/*
458 		 * At this time we don't allow range and start/stop filtering
459 		 * to cohabitate, they have to be mutually exclusive.
460 		 */
461 		if (range && address)
462 			return -EOPNOTSUPP;
463 	}
464 
465 	return 0;
466 }
467 
468 static void etm_addr_filters_sync(struct perf_event *event)
469 {
470 	struct perf_addr_filters_head *head = perf_event_addr_filters(event);
471 	unsigned long start, stop;
472 	struct perf_addr_filter_range *fr = event->addr_filter_ranges;
473 	struct etm_filters *filters = event->hw.addr_filters;
474 	struct etm_filter *etm_filter;
475 	struct perf_addr_filter *filter;
476 	int i = 0;
477 
478 	list_for_each_entry(filter, &head->list, entry) {
479 		start = fr[i].start;
480 		stop = start + fr[i].size;
481 		etm_filter = &filters->etm_filter[i];
482 
483 		switch (filter->action) {
484 		case PERF_ADDR_FILTER_ACTION_FILTER:
485 			etm_filter->start_addr = start;
486 			etm_filter->stop_addr = stop;
487 			etm_filter->type = ETM_ADDR_TYPE_RANGE;
488 			break;
489 		case PERF_ADDR_FILTER_ACTION_START:
490 			etm_filter->start_addr = start;
491 			etm_filter->type = ETM_ADDR_TYPE_START;
492 			break;
493 		case PERF_ADDR_FILTER_ACTION_STOP:
494 			etm_filter->stop_addr = stop;
495 			etm_filter->type = ETM_ADDR_TYPE_STOP;
496 			break;
497 		}
498 		i++;
499 	}
500 
501 	filters->nr_filters = i;
502 }
503 
504 int etm_perf_symlink(struct coresight_device *csdev, bool link)
505 {
506 	char entry[sizeof("cpu9999999")];
507 	int ret = 0, cpu = source_ops(csdev)->cpu_id(csdev);
508 	struct device *pmu_dev = etm_pmu.dev;
509 	struct device *cs_dev = &csdev->dev;
510 
511 	sprintf(entry, "cpu%d", cpu);
512 
513 	if (!etm_perf_up)
514 		return -EPROBE_DEFER;
515 
516 	if (link) {
517 		ret = sysfs_create_link(&pmu_dev->kobj, &cs_dev->kobj, entry);
518 		if (ret)
519 			return ret;
520 		per_cpu(csdev_src, cpu) = csdev;
521 	} else {
522 		sysfs_remove_link(&pmu_dev->kobj, entry);
523 		per_cpu(csdev_src, cpu) = NULL;
524 	}
525 
526 	return 0;
527 }
528 
529 static ssize_t etm_perf_sink_name_show(struct device *dev,
530 				       struct device_attribute *dattr,
531 				       char *buf)
532 {
533 	struct dev_ext_attribute *ea;
534 
535 	ea = container_of(dattr, struct dev_ext_attribute, attr);
536 	return scnprintf(buf, PAGE_SIZE, "0x%lx\n", (unsigned long)(ea->var));
537 }
538 
539 int etm_perf_add_symlink_sink(struct coresight_device *csdev)
540 {
541 	int ret;
542 	unsigned long hash;
543 	const char *name;
544 	struct device *pmu_dev = etm_pmu.dev;
545 	struct device *dev = &csdev->dev;
546 	struct dev_ext_attribute *ea;
547 
548 	if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
549 	    csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
550 		return -EINVAL;
551 
552 	if (csdev->ea != NULL)
553 		return -EINVAL;
554 
555 	if (!etm_perf_up)
556 		return -EPROBE_DEFER;
557 
558 	ea = devm_kzalloc(dev, sizeof(*ea), GFP_KERNEL);
559 	if (!ea)
560 		return -ENOMEM;
561 
562 	name = dev_name(dev);
563 	/* See function coresight_get_sink_by_id() to know where this is used */
564 	hash = hashlen_hash(hashlen_string(NULL, name));
565 
566 	sysfs_attr_init(&ea->attr.attr);
567 	ea->attr.attr.name = devm_kstrdup(dev, name, GFP_KERNEL);
568 	if (!ea->attr.attr.name)
569 		return -ENOMEM;
570 
571 	ea->attr.attr.mode = 0444;
572 	ea->attr.show = etm_perf_sink_name_show;
573 	ea->var = (unsigned long *)hash;
574 
575 	ret = sysfs_add_file_to_group(&pmu_dev->kobj,
576 				      &ea->attr.attr, "sinks");
577 
578 	if (!ret)
579 		csdev->ea = ea;
580 
581 	return ret;
582 }
583 
584 void etm_perf_del_symlink_sink(struct coresight_device *csdev)
585 {
586 	struct device *pmu_dev = etm_pmu.dev;
587 	struct dev_ext_attribute *ea = csdev->ea;
588 
589 	if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
590 	    csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
591 		return;
592 
593 	if (!ea)
594 		return;
595 
596 	sysfs_remove_file_from_group(&pmu_dev->kobj,
597 				     &ea->attr.attr, "sinks");
598 	csdev->ea = NULL;
599 }
600 
601 static int __init etm_perf_init(void)
602 {
603 	int ret;
604 
605 	etm_pmu.capabilities		= (PERF_PMU_CAP_EXCLUSIVE |
606 					   PERF_PMU_CAP_ITRACE);
607 
608 	etm_pmu.attr_groups		= etm_pmu_attr_groups;
609 	etm_pmu.task_ctx_nr		= perf_sw_context;
610 	etm_pmu.read			= etm_event_read;
611 	etm_pmu.event_init		= etm_event_init;
612 	etm_pmu.setup_aux		= etm_setup_aux;
613 	etm_pmu.free_aux		= etm_free_aux;
614 	etm_pmu.start			= etm_event_start;
615 	etm_pmu.stop			= etm_event_stop;
616 	etm_pmu.add			= etm_event_add;
617 	etm_pmu.del			= etm_event_del;
618 	etm_pmu.addr_filters_sync	= etm_addr_filters_sync;
619 	etm_pmu.addr_filters_validate	= etm_addr_filters_validate;
620 	etm_pmu.nr_addr_filters		= ETM_ADDR_CMP_MAX;
621 
622 	ret = perf_pmu_register(&etm_pmu, CORESIGHT_ETM_PMU_NAME, -1);
623 	if (ret == 0)
624 		etm_perf_up = true;
625 
626 	return ret;
627 }
628 device_initcall(etm_perf_init);
629