[linux-2.6-block.git] / tools / perf / arch / x86 / util / intel-bts.c

/*
 * intel-bts.c: Intel Processor Trace support
 * Copyright (c) 2013-2015, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 */

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/bitops.h>
#include <linux/log2.h>

#include "../../util/cpumap.h"
#include "../../util/evsel.h"
#include "../../util/evlist.h"
#include "../../util/session.h"
#include "../../util/util.h"
#include "../../util/pmu.h"
#include "../../util/debug.h"
#include "../../util/tsc.h"
#include "../../util/auxtrace.h"
#include "../../util/intel-bts.h"

#define KiB(x) ((x) * 1024)
#define MiB(x) ((x) * 1024 * 1024)
#define KiB_MASK(x) (KiB(x) - 1)
#define MiB_MASK(x) (MiB(x) - 1)

#define INTEL_BTS_DFLT_SAMPLE_SIZE	KiB(4)

#define INTEL_BTS_MAX_SAMPLE_SIZE	KiB(60)

struct intel_bts_snapshot_ref {
	void	*ref_buf;
	size_t	ref_offset;
	bool	wrapped;
};

struct intel_bts_recording {
	struct auxtrace_record		itr;
	struct perf_pmu			*intel_bts_pmu;
	struct perf_evlist		*evlist;
	bool				snapshot_mode;
	size_t				snapshot_size;
	int				snapshot_ref_cnt;
	struct intel_bts_snapshot_ref	*snapshot_refs;
};

struct branch {
	u64 from;
	u64 to;
	u64 misc;
};

static size_t intel_bts_info_priv_size(struct auxtrace_record *itr __maybe_unused)
{
	return INTEL_BTS_AUXTRACE_PRIV_SIZE;
}

static int intel_bts_info_fill(struct auxtrace_record *itr,
			       struct perf_session *session,
			       struct auxtrace_info_event *auxtrace_info,
			       size_t priv_size)
{
	struct intel_bts_recording *btsr =
			container_of(itr, struct intel_bts_recording, itr);
	struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu;
	struct perf_event_mmap_page *pc;
	struct perf_tsc_conversion tc = { .time_mult = 0, };
	bool cap_user_time_zero = false;
	int err;

	if (priv_size != INTEL_BTS_AUXTRACE_PRIV_SIZE)
		return -EINVAL;

	if (!session->evlist->nr_mmaps)
		return -EINVAL;

	pc = session->evlist->mmap[0].base;
	if (pc) {
		err = perf_read_tsc_conversion(pc, &tc);
		if (err) {
			if (err != -EOPNOTSUPP)
				return err;
		} else {
			cap_user_time_zero = tc.time_mult != 0;
		}
		if (!cap_user_time_zero)
			ui__warning("Intel BTS: TSC not available\n");
	}

	auxtrace_info->type = PERF_AUXTRACE_INTEL_BTS;
	auxtrace_info->priv[INTEL_BTS_PMU_TYPE] = intel_bts_pmu->type;
	auxtrace_info->priv[INTEL_BTS_TIME_SHIFT] = tc.time_shift;
	auxtrace_info->priv[INTEL_BTS_TIME_MULT] = tc.time_mult;
	auxtrace_info->priv[INTEL_BTS_TIME_ZERO] = tc.time_zero;
	auxtrace_info->priv[INTEL_BTS_CAP_USER_TIME_ZERO] = cap_user_time_zero;
	auxtrace_info->priv[INTEL_BTS_SNAPSHOT_MODE] = btsr->snapshot_mode;

	return 0;
}

static int intel_bts_recording_options(struct auxtrace_record *itr,
				       struct perf_evlist *evlist,
				       struct record_opts *opts)
{
	struct intel_bts_recording *btsr =
			container_of(itr, struct intel_bts_recording, itr);
	struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu;
	struct perf_evsel *evsel, *intel_bts_evsel = NULL;
	const struct cpu_map *cpus = evlist->cpus;
	bool privileged = geteuid() == 0 || perf_event_paranoid() < 0;

	btsr->evlist = evlist;
	btsr->snapshot_mode = opts->auxtrace_snapshot_mode;

	evlist__for_each(evlist, evsel) {
		if (evsel->attr.type == intel_bts_pmu->type) {
			if (intel_bts_evsel) {
				pr_err("There may be only one " INTEL_BTS_PMU_NAME " event\n");
				return -EINVAL;
			}
			evsel->attr.freq = 0;
			evsel->attr.sample_period = 1;
			intel_bts_evsel = evsel;
			opts->full_auxtrace = true;
		}
	}

	if (opts->auxtrace_snapshot_mode && !opts->full_auxtrace) {
		pr_err("Snapshot mode (-S option) requires " INTEL_BTS_PMU_NAME " PMU event (-e " INTEL_BTS_PMU_NAME ")\n");
		return -EINVAL;
	}

	if (!opts->full_auxtrace)
		return 0;

	if (opts->full_auxtrace && !cpu_map__empty(cpus)) {
		pr_err(INTEL_BTS_PMU_NAME " does not support per-cpu recording\n");
		return -EINVAL;
	}

	/* Set default sizes for snapshot mode */
	if (opts->auxtrace_snapshot_mode) {
		if (!opts->auxtrace_snapshot_size && !opts->auxtrace_mmap_pages) {
			if (privileged) {
				opts->auxtrace_mmap_pages = MiB(4) / page_size;
			} else {
				opts->auxtrace_mmap_pages = KiB(128) / page_size;
				if (opts->mmap_pages == UINT_MAX)
					opts->mmap_pages = KiB(256) / page_size;
			}
		} else if (!opts->auxtrace_mmap_pages && !privileged &&
			   opts->mmap_pages == UINT_MAX) {
			opts->mmap_pages = KiB(256) / page_size;
		}
		if (!opts->auxtrace_snapshot_size)
			opts->auxtrace_snapshot_size =
				opts->auxtrace_mmap_pages * (size_t)page_size;
		if (!opts->auxtrace_mmap_pages) {
			size_t sz = opts->auxtrace_snapshot_size;

			sz = round_up(sz, page_size) / page_size;
			opts->auxtrace_mmap_pages = roundup_pow_of_two(sz);
		}
		if (opts->auxtrace_snapshot_size >
				opts->auxtrace_mmap_pages * (size_t)page_size) {
			pr_err("Snapshot size %zu must not be greater than AUX area tracing mmap size %zu\n",
			       opts->auxtrace_snapshot_size,
			       opts->auxtrace_mmap_pages * (size_t)page_size);
			return -EINVAL;
		}
		if (!opts->auxtrace_snapshot_size || !opts->auxtrace_mmap_pages) {
			pr_err("Failed to calculate default snapshot size and/or AUX area tracing mmap pages\n");
			return -EINVAL;
		}
		pr_debug2("Intel BTS snapshot size: %zu\n",
			  opts->auxtrace_snapshot_size);
	}

	/* Set default sizes for full trace mode */
	if (opts->full_auxtrace && !opts->auxtrace_mmap_pages) {
		if (privileged) {
			opts->auxtrace_mmap_pages = MiB(4) / page_size;
		} else {
			opts->auxtrace_mmap_pages = KiB(128) / page_size;
			if (opts->mmap_pages == UINT_MAX)
				opts->mmap_pages = KiB(256) / page_size;
		}
	}

	/* Validate auxtrace_mmap_pages */
	if (opts->auxtrace_mmap_pages) {
		size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size;
		size_t min_sz;

		if (opts->auxtrace_snapshot_mode)
			min_sz = KiB(4);
		else
			min_sz = KiB(8);

		if (sz < min_sz || !is_power_of_2(sz)) {
			pr_err("Invalid mmap size for Intel BTS: must be at least %zuKiB and a power of 2\n",
			       min_sz / 1024);
			return -EINVAL;
		}
	}

	if (intel_bts_evsel) {
		/*
		 * To obtain the auxtrace buffer file descriptor, the auxtrace event
		 * must come first.
		 */
		perf_evlist__to_front(evlist, intel_bts_evsel);
		/*
		 * In the case of per-cpu mmaps, we need the CPU on the
		 * AUX event.
		 */
		if (!cpu_map__empty(cpus))
			perf_evsel__set_sample_bit(intel_bts_evsel, CPU);
	}

	/* Add dummy event to keep tracking */
	if (opts->full_auxtrace) {
		struct perf_evsel *tracking_evsel;
		int err;

		err = parse_events(evlist, "dummy:u", NULL);
		if (err)
			return err;

		tracking_evsel = perf_evlist__last(evlist);

		perf_evlist__set_tracking_event(evlist, tracking_evsel);

		tracking_evsel->attr.freq = 0;
		tracking_evsel->attr.sample_period = 1;
	}

	return 0;
}

static int intel_bts_parse_snapshot_options(struct auxtrace_record *itr,
					    struct record_opts *opts,
					    const char *str)
{
	struct intel_bts_recording *btsr =
			container_of(itr, struct intel_bts_recording, itr);
	unsigned long long snapshot_size = 0;
	char *endptr;

	if (str) {
		snapshot_size = strtoull(str, &endptr, 0);
		if (*endptr || snapshot_size > SIZE_MAX)
			return -1;
	}

	opts->auxtrace_snapshot_mode = true;
	opts->auxtrace_snapshot_size = snapshot_size;

	btsr->snapshot_size = snapshot_size;

	return 0;
}

static u64 intel_bts_reference(struct auxtrace_record *itr __maybe_unused)
{
	return rdtsc();
}

static int intel_bts_alloc_snapshot_refs(struct intel_bts_recording *btsr,
					 int idx)
{
	const size_t sz = sizeof(struct intel_bts_snapshot_ref);
	int cnt = btsr->snapshot_ref_cnt, new_cnt = cnt * 2;
	struct intel_bts_snapshot_ref *refs;

	if (!new_cnt)
		new_cnt = 16;

	while (new_cnt <= idx)
		new_cnt *= 2;

	refs = calloc(new_cnt, sz);
	if (!refs)
		return -ENOMEM;

	memcpy(refs, btsr->snapshot_refs, cnt * sz);

	btsr->snapshot_refs = refs;
	btsr->snapshot_ref_cnt = new_cnt;

	return 0;
}

static void intel_bts_free_snapshot_refs(struct intel_bts_recording *btsr)
{
	int i;

	for (i = 0; i < btsr->snapshot_ref_cnt; i++)
		zfree(&btsr->snapshot_refs[i].ref_buf);
	zfree(&btsr->snapshot_refs);
}

static void intel_bts_recording_free(struct auxtrace_record *itr)
{
	struct intel_bts_recording *btsr =
			container_of(itr, struct intel_bts_recording, itr);

	intel_bts_free_snapshot_refs(btsr);
	free(btsr);
}

static int intel_bts_snapshot_start(struct auxtrace_record *itr)
{
	struct intel_bts_recording *btsr =
			container_of(itr, struct intel_bts_recording, itr);
	struct perf_evsel *evsel;

	evlist__for_each(btsr->evlist, evsel) {
		if (evsel->attr.type == btsr->intel_bts_pmu->type)
			return perf_evlist__disable_event(btsr->evlist, evsel);
	}
	return -EINVAL;
}

static int intel_bts_snapshot_finish(struct auxtrace_record *itr)
{
	struct intel_bts_recording *btsr =
			container_of(itr, struct intel_bts_recording, itr);
	struct perf_evsel *evsel;

	evlist__for_each(btsr->evlist, evsel) {
		if (evsel->attr.type == btsr->intel_bts_pmu->type)
			return perf_evlist__enable_event(btsr->evlist, evsel);
	}
	return -EINVAL;
}

static bool intel_bts_first_wrap(u64 *data, size_t buf_size)
{
	int i, a, b;

	b = buf_size >> 3;
	a = b - 512;
	if (a < 0)
		a = 0;

	for (i = a; i < b; i++) {
		if (data[i])
			return true;
	}

	return false;
}

static int intel_bts_find_snapshot(struct auxtrace_record *itr, int idx,
				   struct auxtrace_mmap *mm, unsigned char *data,
				   u64 *head, u64 *old)
{
	struct intel_bts_recording *btsr =
			container_of(itr, struct intel_bts_recording, itr);
	bool wrapped;
	int err;

	pr_debug3("%s: mmap index %d old head %zu new head %zu\n",
		  __func__, idx, (size_t)*old, (size_t)*head);

	if (idx >= btsr->snapshot_ref_cnt) {
		err = intel_bts_alloc_snapshot_refs(btsr, idx);
		if (err)
			goto out_err;
	}

	wrapped = btsr->snapshot_refs[idx].wrapped;
	if (!wrapped && intel_bts_first_wrap((u64 *)data, mm->len)) {
		btsr->snapshot_refs[idx].wrapped = true;
		wrapped = true;
	}

	/*
	 * In full trace mode 'head' continually increases.  However in snapshot
	 * mode 'head' is an offset within the buffer.  Here 'old' and 'head'
	 * are adjusted to match the full trace case which expects that 'old' is
	 * always less than 'head'.
	 */
	if (wrapped) {
		*old = *head;
		*head += mm->len;
	} else {
		if (mm->mask)
			*old &= mm->mask;
		else
			*old %= mm->len;
		if (*old > *head)
			*head += mm->len;
	}

	pr_debug3("%s: wrap-around %sdetected, adjusted old head %zu adjusted new head %zu\n",
		  __func__, wrapped ? "" : "not ", (size_t)*old, (size_t)*head);

	return 0;

out_err:
	pr_err("%s: failed, error %d\n", __func__, err);
	return err;
}

static int intel_bts_read_finish(struct auxtrace_record *itr, int idx)
{
	struct intel_bts_recording *btsr =
			container_of(itr, struct intel_bts_recording, itr);
	struct perf_evsel *evsel;

	evlist__for_each(btsr->evlist, evsel) {
		if (evsel->attr.type == btsr->intel_bts_pmu->type)
			return perf_evlist__enable_event_idx(btsr->evlist,
							     evsel, idx);
	}
	return -EINVAL;
}

struct auxtrace_record *intel_bts_recording_init(int *err)
{
	struct perf_pmu *intel_bts_pmu = perf_pmu__find(INTEL_BTS_PMU_NAME);
	struct intel_bts_recording *btsr;

	if (!intel_bts_pmu)
		return NULL;

	btsr = zalloc(sizeof(struct intel_bts_recording));
	if (!btsr) {
		*err = -ENOMEM;
		return NULL;
	}

	btsr->intel_bts_pmu = intel_bts_pmu;
	btsr->itr.recording_options = intel_bts_recording_options;
	btsr->itr.info_priv_size = intel_bts_info_priv_size;
	btsr->itr.info_fill = intel_bts_info_fill;
	btsr->itr.free = intel_bts_recording_free;
	btsr->itr.snapshot_start = intel_bts_snapshot_start;
	btsr->itr.snapshot_finish = intel_bts_snapshot_finish;
	btsr->itr.find_snapshot = intel_bts_find_snapshot;
	btsr->itr.parse_snapshot_options = intel_bts_parse_snapshot_options;
	btsr->itr.reference = intel_bts_reference;
	btsr->itr.read_finish = intel_bts_read_finish;
	btsr->itr.alignment = sizeof(struct branch);
	return &btsr->itr;
}
Commit	Line	Data
d0170af7 AH	1	/*
	2	* intel-bts.c: Intel Processor Trace support
	3	* Copyright (c) 2013-2015, Intel Corporation.
	4	*
	5	* This program is free software; you can redistribute it and/or modify it
	6	* under the terms and conditions of the GNU General Public License,
	7	* version 2, as published by the Free Software Foundation.
	8	*
	9	* This program is distributed in the hope it will be useful, but WITHOUT
	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	12	* more details.
	13	*
	14	*/
	15
	16	#include <linux/kernel.h>
	17	#include <linux/types.h>
	18	#include <linux/bitops.h>
	19	#include <linux/log2.h>
	20
	21	#include "../../util/cpumap.h"
	22	#include "../../util/evsel.h"
	23	#include "../../util/evlist.h"
	24	#include "../../util/session.h"
	25	#include "../../util/util.h"
	26	#include "../../util/pmu.h"
	27	#include "../../util/debug.h"
	28	#include "../../util/tsc.h"
	29	#include "../../util/auxtrace.h"
	30	#include "../../util/intel-bts.h"
	31
	32	#define KiB(x) ((x) * 1024)
	33	#define MiB(x) ((x) * 1024 * 1024)
	34	#define KiB_MASK(x) (KiB(x) - 1)
	35	#define MiB_MASK(x) (MiB(x) - 1)
	36
	37	#define INTEL_BTS_DFLT_SAMPLE_SIZE KiB(4)
	38
	39	#define INTEL_BTS_MAX_SAMPLE_SIZE KiB(60)
	40
	41	struct intel_bts_snapshot_ref {
	42	void *ref_buf;
	43	size_t ref_offset;
	44	bool wrapped;
	45	};
	46
	47	struct intel_bts_recording {
	48	struct auxtrace_record itr;
	49	struct perf_pmu *intel_bts_pmu;
	50	struct perf_evlist *evlist;
	51	bool snapshot_mode;
	52	size_t snapshot_size;
	53	int snapshot_ref_cnt;
	54	struct intel_bts_snapshot_ref *snapshot_refs;
	55	};
	56
	57	struct branch {
	58	u64 from;
	59	u64 to;
	60	u64 misc;
	61	};
	62
	63	static size_t intel_bts_info_priv_size(struct auxtrace_record *itr __maybe_unused)
	64	{
65	return INTEL_BTS_AUXTRACE_PRIV_SIZE;
66	}
67
68	static int intel_bts_info_fill(struct auxtrace_record *itr,
69	struct perf_session *session,
70	struct auxtrace_info_event *auxtrace_info,
71	size_t priv_size)
72	{
73	struct intel_bts_recording *btsr =
74	container_of(itr, struct intel_bts_recording, itr);
75	struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu;
76	struct perf_event_mmap_page *pc;
77	struct perf_tsc_conversion tc = { .time_mult = 0, };
78	bool cap_user_time_zero = false;
79	int err;
80
81	if (priv_size != INTEL_BTS_AUXTRACE_PRIV_SIZE)
82	return -EINVAL;
83
84	if (!session->evlist->nr_mmaps)
85	return -EINVAL;
86
87	pc = session->evlist->mmap[0].base;
88	if (pc) {
89	err = perf_read_tsc_conversion(pc, &tc);
90	if (err) {
91	if (err != -EOPNOTSUPP)
92	return err;
93	} else {
94	cap_user_time_zero = tc.time_mult != 0;
95	}
96	if (!cap_user_time_zero)
97	ui__warning("Intel BTS: TSC not available\n");
98	}
99
100	auxtrace_info->type = PERF_AUXTRACE_INTEL_BTS;
101	auxtrace_info->priv[INTEL_BTS_PMU_TYPE] = intel_bts_pmu->type;
102	auxtrace_info->priv[INTEL_BTS_TIME_SHIFT] = tc.time_shift;
103	auxtrace_info->priv[INTEL_BTS_TIME_MULT] = tc.time_mult;
104	auxtrace_info->priv[INTEL_BTS_TIME_ZERO] = tc.time_zero;
105	auxtrace_info->priv[INTEL_BTS_CAP_USER_TIME_ZERO] = cap_user_time_zero;
106	auxtrace_info->priv[INTEL_BTS_SNAPSHOT_MODE] = btsr->snapshot_mode;
107
108	return 0;
109	}
110
111	static int intel_bts_recording_options(struct auxtrace_record *itr,
112	struct perf_evlist *evlist,
113	struct record_opts *opts)
114	{
115	struct intel_bts_recording *btsr =
116	container_of(itr, struct intel_bts_recording, itr);
117	struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu;
118	struct perf_evsel evsel, intel_bts_evsel = NULL;
119	const struct cpu_map *cpus = evlist->cpus;
120	bool privileged = geteuid() == 0 \|\| perf_event_paranoid() < 0;
121
122	btsr->evlist = evlist;
123	btsr->snapshot_mode = opts->auxtrace_snapshot_mode;
124
125	evlist__for_each(evlist, evsel) {
126	if (evsel->attr.type == intel_bts_pmu->type) {
127	if (intel_bts_evsel) {
128	pr_err("There may be only one " INTEL_BTS_PMU_NAME " event\n");
129	return -EINVAL;
130	}
131	evsel->attr.freq = 0;
132	evsel->attr.sample_period = 1;
133	intel_bts_evsel = evsel;
134	opts->full_auxtrace = true;
135	}
136	}
137
138	if (opts->auxtrace_snapshot_mode && !opts->full_auxtrace) {
139	pr_err("Snapshot mode (-S option) requires " INTEL_BTS_PMU_NAME " PMU event (-e " INTEL_BTS_PMU_NAME ")\n");
140	return -EINVAL;
141	}
142
143	if (!opts->full_auxtrace)
144	return 0;
145
146	if (opts->full_auxtrace && !cpu_map__empty(cpus)) {
147	pr_err(INTEL_BTS_PMU_NAME " does not support per-cpu recording\n");
148	return -EINVAL;
149	}
150
151	/* Set default sizes for snapshot mode */
152	if (opts->auxtrace_snapshot_mode) {
153	if (!opts->auxtrace_snapshot_size && !opts->auxtrace_mmap_pages) {
154	if (privileged) {
155	opts->auxtrace_mmap_pages = MiB(4) / page_size;
156	} else {
157	opts->auxtrace_mmap_pages = KiB(128) / page_size;
158	if (opts->mmap_pages == UINT_MAX)
159	opts->mmap_pages = KiB(256) / page_size;
160	}
161	} else if (!opts->auxtrace_mmap_pages && !privileged &&
162	opts->mmap_pages == UINT_MAX) {
163	opts->mmap_pages = KiB(256) / page_size;
164	}
165	if (!opts->auxtrace_snapshot_size)
166	opts->auxtrace_snapshot_size =
167	opts->auxtrace_mmap_pages * (size_t)page_size;
168	if (!opts->auxtrace_mmap_pages) {
169	size_t sz = opts->auxtrace_snapshot_size;
170
171	sz = round_up(sz, page_size) / page_size;
172	opts->auxtrace_mmap_pages = roundup_pow_of_two(sz);
173	}
174	if (opts->auxtrace_snapshot_size >
175	opts->auxtrace_mmap_pages * (size_t)page_size) {
176	pr_err("Snapshot size %zu must not be greater than AUX area tracing mmap size %zu\n",
177	opts->auxtrace_snapshot_size,
178	opts->auxtrace_mmap_pages * (size_t)page_size);
179	return -EINVAL;
180	}
181	if (!opts->auxtrace_snapshot_size \|\| !opts->auxtrace_mmap_pages) {
182	pr_err("Failed to calculate default snapshot size and/or AUX area tracing mmap pages\n");
183	return -EINVAL;
184	}
185	pr_debug2("Intel BTS snapshot size: %zu\n",
186	opts->auxtrace_snapshot_size);
187	}
188
189	/* Set default sizes for full trace mode */
190	if (opts->full_auxtrace && !opts->auxtrace_mmap_pages) {
191	if (privileged) {
192	opts->auxtrace_mmap_pages = MiB(4) / page_size;
193	} else {
194	opts->auxtrace_mmap_pages = KiB(128) / page_size;
195	if (opts->mmap_pages == UINT_MAX)
196	opts->mmap_pages = KiB(256) / page_size;
197	}
198	}
199
200	/* Validate auxtrace_mmap_pages */
201	if (opts->auxtrace_mmap_pages) {
202	size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size;
203	size_t min_sz;
204
205	if (opts->auxtrace_snapshot_mode)
206	min_sz = KiB(4);
207	else
208	min_sz = KiB(8);
209
210	if (sz < min_sz \|\| !is_power_of_2(sz)) {
211	pr_err("Invalid mmap size for Intel BTS: must be at least %zuKiB and a power of 2\n",
212	min_sz / 1024);
213	return -EINVAL;
214	}
215	}
216
217	if (intel_bts_evsel) {
218	/*
219	* To obtain the auxtrace buffer file descriptor, the auxtrace event
220	* must come first.
221	*/
222	perf_evlist__to_front(evlist, intel_bts_evsel);
223	/*
224	* In the case of per-cpu mmaps, we need the CPU on the
225	* AUX event.
226	*/
227	if (!cpu_map__empty(cpus))
228	perf_evsel__set_sample_bit(intel_bts_evsel, CPU);
229	}
230
231	/* Add dummy event to keep tracking */
232	if (opts->full_auxtrace) {
233	struct perf_evsel *tracking_evsel;
234	int err;
235
236	err = parse_events(evlist, "dummy:u", NULL);
237	if (err)
238	return err;
239
240	tracking_evsel = perf_evlist__last(evlist);
241
242	perf_evlist__set_tracking_event(evlist, tracking_evsel);
243
244	tracking_evsel->attr.freq = 0;
245	tracking_evsel->attr.sample_period = 1;
246	}
247
248	return 0;
249	}
250
251	static int intel_bts_parse_snapshot_options(struct auxtrace_record *itr,
252	struct record_opts *opts,
253	const char *str)
254	{
255	struct intel_bts_recording *btsr =
256	container_of(itr, struct intel_bts_recording, itr);
257	unsigned long long snapshot_size = 0;
258	char *endptr;
259
260	if (str) {
261	snapshot_size = strtoull(str, &endptr, 0);
262	if (*endptr \|\| snapshot_size > SIZE_MAX)
263	return -1;
264	}
265
266	opts->auxtrace_snapshot_mode = true;
267	opts->auxtrace_snapshot_size = snapshot_size;
268
269	btsr->snapshot_size = snapshot_size;
270
271	return 0;
272	}
273
274	static u64 intel_bts_reference(struct auxtrace_record *itr __maybe_unused)
275	{
276	return rdtsc();
277	}
278
279	static int intel_bts_alloc_snapshot_refs(struct intel_bts_recording *btsr,
280	int idx)
281	{
282	const size_t sz = sizeof(struct intel_bts_snapshot_ref);
283	int cnt = btsr->snapshot_ref_cnt, new_cnt = cnt * 2;
284	struct intel_bts_snapshot_ref *refs;
285
286	if (!new_cnt)
287	new_cnt = 16;
288
289	while (new_cnt <= idx)
290	new_cnt *= 2;
291
292	refs = calloc(new_cnt, sz);
293	if (!refs)
294	return -ENOMEM;
295
296	memcpy(refs, btsr->snapshot_refs, cnt * sz);
297
298	btsr->snapshot_refs = refs;
299	btsr->snapshot_ref_cnt = new_cnt;
300
301	return 0;
302	}
303
304	static void intel_bts_free_snapshot_refs(struct intel_bts_recording *btsr)
305	{
306	int i;
307
308	for (i = 0; i < btsr->snapshot_ref_cnt; i++)
309	zfree(&btsr->snapshot_refs[i].ref_buf);
310	zfree(&btsr->snapshot_refs);
311	}
312
313	static void intel_bts_recording_free(struct auxtrace_record *itr)
314	{
315	struct intel_bts_recording *btsr =
316	container_of(itr, struct intel_bts_recording, itr);
317
318	intel_bts_free_snapshot_refs(btsr);
319	free(btsr);
320	}
321
322	static int intel_bts_snapshot_start(struct auxtrace_record *itr)
323	{
324	struct intel_bts_recording *btsr =
325	container_of(itr, struct intel_bts_recording, itr);
326	struct perf_evsel *evsel;
327
328	evlist__for_each(btsr->evlist, evsel) {
329	if (evsel->attr.type == btsr->intel_bts_pmu->type)
330	return perf_evlist__disable_event(btsr->evlist, evsel);
331	}
332	return -EINVAL;
333	}
334
335	static int intel_bts_snapshot_finish(struct auxtrace_record *itr)
336	{
337	struct intel_bts_recording *btsr =
338	container_of(itr, struct intel_bts_recording, itr);
339	struct perf_evsel *evsel;
340
341	evlist__for_each(btsr->evlist, evsel) {
342	if (evsel->attr.type == btsr->intel_bts_pmu->type)
343	return perf_evlist__enable_event(btsr->evlist, evsel);
344	}
345	return -EINVAL;
346	}
347
348	static bool intel_bts_first_wrap(u64 *data, size_t buf_size)
349	{
350	int i, a, b;
351
352	b = buf_size >> 3;
353	a = b - 512;
354	if (a < 0)
355	a = 0;
356
357	for (i = a; i < b; i++) {
358	if (data[i])
359	return true;
360	}
361
362	return false;
363	}
364
365	static int intel_bts_find_snapshot(struct auxtrace_record *itr, int idx,
366	struct auxtrace_mmap mm, unsigned char data,
367	u64 head, u64 old)
368	{
369	struct intel_bts_recording *btsr =
370	container_of(itr, struct intel_bts_recording, itr);
371	bool wrapped;
372	int err;
373
374	pr_debug3("%s: mmap index %d old head %zu new head %zu\n",
375	__func__, idx, (size_t)old, (size_t)head);
376
377	if (idx >= btsr->snapshot_ref_cnt) {
378	err = intel_bts_alloc_snapshot_refs(btsr, idx);
379	if (err)
380	goto out_err;
381	}
382
383	wrapped = btsr->snapshot_refs[idx].wrapped;
384	if (!wrapped && intel_bts_first_wrap((u64 *)data, mm->len)) {
385	btsr->snapshot_refs[idx].wrapped = true;
386	wrapped = true;
387	}
388
389	/*
390	* In full trace mode 'head' continually increases. However in snapshot
391	* mode 'head' is an offset within the buffer. Here 'old' and 'head'
392	* are adjusted to match the full trace case which expects that 'old' is
393	* always less than 'head'.
394	*/
395	if (wrapped) {
396	old = head;
397	*head += mm->len;
398	} else {
399	if (mm->mask)
400	*old &= mm->mask;
401	else
402	*old %= mm->len;
403	if (old > head)
404	*head += mm->len;
405	}
406
407	pr_debug3("%s: wrap-around %sdetected, adjusted old head %zu adjusted new head %zu\n",
408	__func__, wrapped ? "" : "not ", (size_t)old, (size_t)head);
409
410	return 0;
411
412	out_err:
413	pr_err("%s: failed, error %d\n", __func__, err);
414	return err;
415	}
416
417	static int intel_bts_read_finish(struct auxtrace_record *itr, int idx)
418	{
419	struct intel_bts_recording *btsr =
420	container_of(itr, struct intel_bts_recording, itr);
421	struct perf_evsel *evsel;
422
423	evlist__for_each(btsr->evlist, evsel) {
424	if (evsel->attr.type == btsr->intel_bts_pmu->type)
425	return perf_evlist__enable_event_idx(btsr->evlist,
426	evsel, idx);
427	}
428	return -EINVAL;
429	}
430
431	struct auxtrace_record intel_bts_recording_init(int err)
432	{
433	struct perf_pmu *intel_bts_pmu = perf_pmu__find(INTEL_BTS_PMU_NAME);
434	struct intel_bts_recording *btsr;
435
436	if (!intel_bts_pmu)
437	return NULL;
438
439	btsr = zalloc(sizeof(struct intel_bts_recording));
440	if (!btsr) {
441	*err = -ENOMEM;
442	return NULL;
443	}
444
445	btsr->intel_bts_pmu = intel_bts_pmu;
446	btsr->itr.recording_options = intel_bts_recording_options;
447	btsr->itr.info_priv_size = intel_bts_info_priv_size;
448	btsr->itr.info_fill = intel_bts_info_fill;
449	btsr->itr.free = intel_bts_recording_free;
450	btsr->itr.snapshot_start = intel_bts_snapshot_start;
451	btsr->itr.snapshot_finish = intel_bts_snapshot_finish;
452	btsr->itr.find_snapshot = intel_bts_find_snapshot;
453	btsr->itr.parse_snapshot_options = intel_bts_parse_snapshot_options;
454	btsr->itr.reference = intel_bts_reference;
455	btsr->itr.read_finish = intel_bts_read_finish;
456	btsr->itr.alignment = sizeof(struct branch);
457	return &btsr->itr;
458	}