// SPDX-License-Identifier: GPL-2.0-only
/*
 * intel-bts.c: Intel Processor Trace support
 * Copyright (c) 2013-2015, Intel Corporation.
 */

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

#include "../../../util/cpumap.h"
#include "../../../util/event.h"
#include "../../../util/evsel.h"
#include "../../../util/evlist.h"
#include "../../../util/mmap.h"
#include "../../../util/session.h"
#include "../../../util/pmus.h"
#include "../../../util/debug.h"
#include "../../../util/record.h"
#include "../../../util/tsc.h"
#include "../../../util/auxtrace.h"
#include "../../../util/intel-bts.h"
#include <internal/lib.h> // page_size

#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)

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 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,
                         struct evlist *evlist __maybe_unused)
{
        return INTEL_BTS_AUXTRACE_PRIV_SIZE;
}

static int intel_bts_info_fill(struct auxtrace_record *itr,
                               struct perf_session *session,
                               struct perf_record_auxtrace_info *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->core.nr_mmaps)
                return -EINVAL;

        pc = session->evlist->mmap[0].core.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 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 evsel *evsel, *intel_bts_evsel = NULL;
        const struct perf_cpu_map *cpus = evlist->core.user_requested_cpus;
        bool privileged = perf_event_paranoid_check(-1);

        if (opts->auxtrace_sample_mode) {
                pr_err("Intel BTS does not support AUX area sampling\n");
                return -EINVAL;
        }

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

        evlist__for_each_entry(evlist, evsel) {
                if (evsel->core.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->core.attr.freq = 0;
                        evsel->core.attr.sample_period = 1;
                        evsel->needs_auxtrace_mmap = true;
                        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 && !perf_cpu_map__is_any_cpu_or_is_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.
                 */
                evlist__to_front(evlist, intel_bts_evsel);
                /*
                 * In the case of per-cpu mmaps, we need the CPU on the
                 * AUX event.
                 */
                if (!perf_cpu_map__is_any_cpu_or_is_empty(cpus))
                        evsel__set_sample_bit(intel_bts_evsel, CPU);
        }

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

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

                tracking_evsel = evlist__last(evlist);

                evlist__set_tracking_event(evlist, tracking_evsel);

                tracking_evsel->core.attr.freq = 0;
                tracking_evsel->core.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 evsel *evsel;

        evlist__for_each_entry(btsr->evlist, evsel) {
                if (evsel->core.attr.type == btsr->intel_bts_pmu->type)
                        return evsel__disable(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 evsel *evsel;

        evlist__for_each_entry(btsr->evlist, evsel) {
                if (evsel->core.attr.type == btsr->intel_bts_pmu->type)
                        return evsel__enable(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;
}

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

        if (!intel_bts_pmu)
                return NULL;

        if (setenv("JITDUMP_USE_ARCH_TIMESTAMP", "1", 1)) {
                *err = -errno;
                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 = auxtrace_record__read_finish;
        btsr->itr.alignment = sizeof(struct branch);
        return &btsr->itr;
}