1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * intel-bts.c: Intel Processor Trace support
4 * Copyright (c) 2013-2015, Intel Corporation.
5 */
6
7#include <errno.h>
8#include <linux/kernel.h>
9#include <linux/types.h>
10#include <linux/bitops.h>
11#include <linux/log2.h>
12#include <linux/zalloc.h>
13
14#include "../../../util/cpumap.h"
15#include "../../../util/event.h"
16#include "../../../util/evsel.h"
17#include "../../../util/evlist.h"
18#include "../../../util/mmap.h"
19#include "../../../util/session.h"
20#include "../../../util/pmu.h"
21#include "../../../util/debug.h"
22#include "../../../util/record.h"
23#include "../../../util/tsc.h"
24#include "../../../util/auxtrace.h"
25#include "../../../util/intel-bts.h"
26#include <internal/lib.h> // page_size
27
28#define KiB(x) ((x) * 1024)
29#define MiB(x) ((x) * 1024 * 1024)
30#define KiB_MASK(x) (KiB(x) - 1)
31#define MiB_MASK(x) (MiB(x) - 1)
32
33struct intel_bts_snapshot_ref {
34	void	*ref_buf;
35	size_t	ref_offset;
36	bool	wrapped;
37};
38
39struct intel_bts_recording {
40	struct auxtrace_record		itr;
41	struct perf_pmu			*intel_bts_pmu;
42	struct evlist		*evlist;
43	bool				snapshot_mode;
44	size_t				snapshot_size;
45	int				snapshot_ref_cnt;
46	struct intel_bts_snapshot_ref	*snapshot_refs;
47};
48
49struct branch {
50	u64 from;
51	u64 to;
52	u64 misc;
53};
54
55static size_t
56intel_bts_info_priv_size(struct auxtrace_record *itr __maybe_unused,
57			 struct evlist *evlist __maybe_unused)
58{
59	return INTEL_BTS_AUXTRACE_PRIV_SIZE;
60}
61
62static int intel_bts_info_fill(struct auxtrace_record *itr,
63			       struct perf_session *session,
64			       struct perf_record_auxtrace_info *auxtrace_info,
65			       size_t priv_size)
66{
67	struct intel_bts_recording *btsr =
68			container_of(itr, struct intel_bts_recording, itr);
69	struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu;
70	struct perf_event_mmap_page *pc;
71	struct perf_tsc_conversion tc = { .time_mult = 0, };
72	bool cap_user_time_zero = false;
73	int err;
74
75	if (priv_size != INTEL_BTS_AUXTRACE_PRIV_SIZE)
76		return -EINVAL;
77
78	if (!session->evlist->core.nr_mmaps)
79		return -EINVAL;
80
81	pc = session->evlist->mmap[0].core.base;
82	if (pc) {
83		err = perf_read_tsc_conversion(pc, &tc);
84		if (err) {
85			if (err != -EOPNOTSUPP)
86				return err;
87		} else {
88			cap_user_time_zero = tc.time_mult != 0;
89		}
90		if (!cap_user_time_zero)
91			ui__warning("Intel BTS: TSC not available\n");
92	}
93
94	auxtrace_info->type = PERF_AUXTRACE_INTEL_BTS;
95	auxtrace_info->priv[INTEL_BTS_PMU_TYPE] = intel_bts_pmu->type;
96	auxtrace_info->priv[INTEL_BTS_TIME_SHIFT] = tc.time_shift;
97	auxtrace_info->priv[INTEL_BTS_TIME_MULT] = tc.time_mult;
98	auxtrace_info->priv[INTEL_BTS_TIME_ZERO] = tc.time_zero;
99	auxtrace_info->priv[INTEL_BTS_CAP_USER_TIME_ZERO] = cap_user_time_zero;
100	auxtrace_info->priv[INTEL_BTS_SNAPSHOT_MODE] = btsr->snapshot_mode;
101
102	return 0;
103}
104
105static int intel_bts_recording_options(struct auxtrace_record *itr,
106				       struct evlist *evlist,
107				       struct record_opts *opts)
108{
109	struct intel_bts_recording *btsr =
110			container_of(itr, struct intel_bts_recording, itr);
111	struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu;
112	struct evsel *evsel, *intel_bts_evsel = NULL;
113	const struct perf_cpu_map *cpus = evlist->core.cpus;
114	bool privileged = perf_event_paranoid_check(-1);
115
116	if (opts->auxtrace_sample_mode) {
117		pr_err("Intel BTS does not support AUX area sampling\n");
118		return -EINVAL;
119	}
120
121	btsr->evlist = evlist;
122	btsr->snapshot_mode = opts->auxtrace_snapshot_mode;
123
124	evlist__for_each_entry(evlist, evsel) {
125		if (evsel->core.attr.type == intel_bts_pmu->type) {
126			if (intel_bts_evsel) {
127				pr_err("There may be only one " INTEL_BTS_PMU_NAME " event\n");
128				return -EINVAL;
129			}
130			evsel->core.attr.freq = 0;
131			evsel->core.attr.sample_period = 1;
132			intel_bts_evsel = evsel;
133			opts->full_auxtrace = true;
134		}
135	}
136
137	if (opts->auxtrace_snapshot_mode && !opts->full_auxtrace) {
138		pr_err("Snapshot mode (-S option) requires " INTEL_BTS_PMU_NAME " PMU event (-e " INTEL_BTS_PMU_NAME ")\n");
139		return -EINVAL;
140	}
141
142	if (!opts->full_auxtrace)
143		return 0;
144
145	if (opts->full_auxtrace && !perf_cpu_map__empty(cpus)) {
146		pr_err(INTEL_BTS_PMU_NAME " does not support per-cpu recording\n");
147		return -EINVAL;
148	}
149
150	/* Set default sizes for snapshot mode */
151	if (opts->auxtrace_snapshot_mode) {
152		if (!opts->auxtrace_snapshot_size && !opts->auxtrace_mmap_pages) {
153			if (privileged) {
154				opts->auxtrace_mmap_pages = MiB(4) / page_size;
155			} else {
156				opts->auxtrace_mmap_pages = KiB(128) / page_size;
157				if (opts->mmap_pages == UINT_MAX)
158					opts->mmap_pages = KiB(256) / page_size;
159			}
160		} else if (!opts->auxtrace_mmap_pages && !privileged &&
161			   opts->mmap_pages == UINT_MAX) {
162			opts->mmap_pages = KiB(256) / page_size;
163		}
164		if (!opts->auxtrace_snapshot_size)
165			opts->auxtrace_snapshot_size =
166				opts->auxtrace_mmap_pages * (size_t)page_size;
167		if (!opts->auxtrace_mmap_pages) {
168			size_t sz = opts->auxtrace_snapshot_size;
169
170			sz = round_up(sz, page_size) / page_size;
171			opts->auxtrace_mmap_pages = roundup_pow_of_two(sz);
172		}
173		if (opts->auxtrace_snapshot_size >
174				opts->auxtrace_mmap_pages * (size_t)page_size) {
175			pr_err("Snapshot size %zu must not be greater than AUX area tracing mmap size %zu\n",
176			       opts->auxtrace_snapshot_size,
177			       opts->auxtrace_mmap_pages * (size_t)page_size);
178			return -EINVAL;
179		}
180		if (!opts->auxtrace_snapshot_size || !opts->auxtrace_mmap_pages) {
181			pr_err("Failed to calculate default snapshot size and/or AUX area tracing mmap pages\n");
182			return -EINVAL;
183		}
184		pr_debug2("Intel BTS snapshot size: %zu\n",
185			  opts->auxtrace_snapshot_size);
186	}
187
188	/* Set default sizes for full trace mode */
189	if (opts->full_auxtrace && !opts->auxtrace_mmap_pages) {
190		if (privileged) {
191			opts->auxtrace_mmap_pages = MiB(4) / page_size;
192		} else {
193			opts->auxtrace_mmap_pages = KiB(128) / page_size;
194			if (opts->mmap_pages == UINT_MAX)
195				opts->mmap_pages = KiB(256) / page_size;
196		}
197	}
198
199	/* Validate auxtrace_mmap_pages */
200	if (opts->auxtrace_mmap_pages) {
201		size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size;
202		size_t min_sz;
203
204		if (opts->auxtrace_snapshot_mode)
205			min_sz = KiB(4);
206		else
207			min_sz = KiB(8);
208
209		if (sz < min_sz || !is_power_of_2(sz)) {
210			pr_err("Invalid mmap size for Intel BTS: must be at least %zuKiB and a power of 2\n",
211			       min_sz / 1024);
212			return -EINVAL;
213		}
214	}
215
216	if (intel_bts_evsel) {
217		/*
218		 * To obtain the auxtrace buffer file descriptor, the auxtrace event
219		 * must come first.
220		 */
221		perf_evlist__to_front(evlist, intel_bts_evsel);
222		/*
223		 * In the case of per-cpu mmaps, we need the CPU on the
224		 * AUX event.
225		 */
226		if (!perf_cpu_map__empty(cpus))
227			evsel__set_sample_bit(intel_bts_evsel, CPU);
228	}
229
230	/* Add dummy event to keep tracking */
231	if (opts->full_auxtrace) {
232		struct evsel *tracking_evsel;
233		int err;
234
235		err = parse_events(evlist, "dummy:u", NULL);
236		if (err)
237			return err;
238
239		tracking_evsel = evlist__last(evlist);
240
241		perf_evlist__set_tracking_event(evlist, tracking_evsel);
242
243		tracking_evsel->core.attr.freq = 0;
244		tracking_evsel->core.attr.sample_period = 1;
245	}
246
247	return 0;
248}
249
250static int intel_bts_parse_snapshot_options(struct auxtrace_record *itr,
251					    struct record_opts *opts,
252					    const char *str)
253{
254	struct intel_bts_recording *btsr =
255			container_of(itr, struct intel_bts_recording, itr);
256	unsigned long long snapshot_size = 0;
257	char *endptr;
258
259	if (str) {
260		snapshot_size = strtoull(str, &endptr, 0);
261		if (*endptr || snapshot_size > SIZE_MAX)
262			return -1;
263	}
264
265	opts->auxtrace_snapshot_mode = true;
266	opts->auxtrace_snapshot_size = snapshot_size;
267
268	btsr->snapshot_size = snapshot_size;
269
270	return 0;
271}
272
273static u64 intel_bts_reference(struct auxtrace_record *itr __maybe_unused)
274{
275	return rdtsc();
276}
277
278static int intel_bts_alloc_snapshot_refs(struct intel_bts_recording *btsr,
279					 int idx)
280{
281	const size_t sz = sizeof(struct intel_bts_snapshot_ref);
282	int cnt = btsr->snapshot_ref_cnt, new_cnt = cnt * 2;
283	struct intel_bts_snapshot_ref *refs;
284
285	if (!new_cnt)
286		new_cnt = 16;
287
288	while (new_cnt <= idx)
289		new_cnt *= 2;
290
291	refs = calloc(new_cnt, sz);
292	if (!refs)
293		return -ENOMEM;
294
295	memcpy(refs, btsr->snapshot_refs, cnt * sz);
296
297	btsr->snapshot_refs = refs;
298	btsr->snapshot_ref_cnt = new_cnt;
299
300	return 0;
301}
302
303static void intel_bts_free_snapshot_refs(struct intel_bts_recording *btsr)
304{
305	int i;
306
307	for (i = 0; i < btsr->snapshot_ref_cnt; i++)
308		zfree(&btsr->snapshot_refs[i].ref_buf);
309	zfree(&btsr->snapshot_refs);
310}
311
312static void intel_bts_recording_free(struct auxtrace_record *itr)
313{
314	struct intel_bts_recording *btsr =
315			container_of(itr, struct intel_bts_recording, itr);
316
317	intel_bts_free_snapshot_refs(btsr);
318	free(btsr);
319}
320
321static int intel_bts_snapshot_start(struct auxtrace_record *itr)
322{
323	struct intel_bts_recording *btsr =
324			container_of(itr, struct intel_bts_recording, itr);
325	struct evsel *evsel;
326
327	evlist__for_each_entry(btsr->evlist, evsel) {
328		if (evsel->core.attr.type == btsr->intel_bts_pmu->type)
329			return evsel__disable(evsel);
330	}
331	return -EINVAL;
332}
333
334static int intel_bts_snapshot_finish(struct auxtrace_record *itr)
335{
336	struct intel_bts_recording *btsr =
337			container_of(itr, struct intel_bts_recording, itr);
338	struct evsel *evsel;
339
340	evlist__for_each_entry(btsr->evlist, evsel) {
341		if (evsel->core.attr.type == btsr->intel_bts_pmu->type)
342			return evsel__enable(evsel);
343	}
344	return -EINVAL;
345}
346
347static bool intel_bts_first_wrap(u64 *data, size_t buf_size)
348{
349	int i, a, b;
350
351	b = buf_size >> 3;
352	a = b - 512;
353	if (a < 0)
354		a = 0;
355
356	for (i = a; i < b; i++) {
357		if (data[i])
358			return true;
359	}
360
361	return false;
362}
363
364static int intel_bts_find_snapshot(struct auxtrace_record *itr, int idx,
365				   struct auxtrace_mmap *mm, unsigned char *data,
366				   u64 *head, u64 *old)
367{
368	struct intel_bts_recording *btsr =
369			container_of(itr, struct intel_bts_recording, itr);
370	bool wrapped;
371	int err;
372
373	pr_debug3("%s: mmap index %d old head %zu new head %zu\n",
374		  __func__, idx, (size_t)*old, (size_t)*head);
375
376	if (idx >= btsr->snapshot_ref_cnt) {
377		err = intel_bts_alloc_snapshot_refs(btsr, idx);
378		if (err)
379			goto out_err;
380	}
381
382	wrapped = btsr->snapshot_refs[idx].wrapped;
383	if (!wrapped && intel_bts_first_wrap((u64 *)data, mm->len)) {
384		btsr->snapshot_refs[idx].wrapped = true;
385		wrapped = true;
386	}
387
388	/*
389	 * In full trace mode 'head' continually increases.  However in snapshot
390	 * mode 'head' is an offset within the buffer.  Here 'old' and 'head'
391	 * are adjusted to match the full trace case which expects that 'old' is
392	 * always less than 'head'.
393	 */
394	if (wrapped) {
395		*old = *head;
396		*head += mm->len;
397	} else {
398		if (mm->mask)
399			*old &= mm->mask;
400		else
401			*old %= mm->len;
402		if (*old > *head)
403			*head += mm->len;
404	}
405
406	pr_debug3("%s: wrap-around %sdetected, adjusted old head %zu adjusted new head %zu\n",
407		  __func__, wrapped ? "" : "not ", (size_t)*old, (size_t)*head);
408
409	return 0;
410
411out_err:
412	pr_err("%s: failed, error %d\n", __func__, err);
413	return err;
414}
415
416struct auxtrace_record *intel_bts_recording_init(int *err)
417{
418	struct perf_pmu *intel_bts_pmu = perf_pmu__find(INTEL_BTS_PMU_NAME);
419	struct intel_bts_recording *btsr;
420
421	if (!intel_bts_pmu)
422		return NULL;
423
424	if (setenv("JITDUMP_USE_ARCH_TIMESTAMP", "1", 1)) {
425		*err = -errno;
426		return NULL;
427	}
428
429	btsr = zalloc(sizeof(struct intel_bts_recording));
430	if (!btsr) {
431		*err = -ENOMEM;
432		return NULL;
433	}
434
435	btsr->intel_bts_pmu = intel_bts_pmu;
436	btsr->itr.pmu = intel_bts_pmu;
437	btsr->itr.recording_options = intel_bts_recording_options;
438	btsr->itr.info_priv_size = intel_bts_info_priv_size;
439	btsr->itr.info_fill = intel_bts_info_fill;
440	btsr->itr.free = intel_bts_recording_free;
441	btsr->itr.snapshot_start = intel_bts_snapshot_start;
442	btsr->itr.snapshot_finish = intel_bts_snapshot_finish;
443	btsr->itr.find_snapshot = intel_bts_find_snapshot;
444	btsr->itr.parse_snapshot_options = intel_bts_parse_snapshot_options;
445	btsr->itr.reference = intel_bts_reference;
446	btsr->itr.read_finish = auxtrace_record__read_finish;
447	btsr->itr.alignment = sizeof(struct branch);
448	return &btsr->itr;
449}
450