cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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sideband_evlist.c (3505B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2
      3#include "util/debug.h"
      4#include "util/evlist.h"
      5#include "util/evsel.h"
      6#include "util/mmap.h"
      7#include "util/perf_api_probe.h"
      8#include <perf/mmap.h>
      9#include <linux/perf_event.h>
     10#include <limits.h>
     11#include <pthread.h>
     12#include <sched.h>
     13#include <stdbool.h>
     14
     15int evlist__add_sb_event(struct evlist *evlist, struct perf_event_attr *attr,
     16			 evsel__sb_cb_t cb, void *data)
     17{
     18	struct evsel *evsel;
     19
     20	if (!attr->sample_id_all) {
     21		pr_warning("enabling sample_id_all for all side band events\n");
     22		attr->sample_id_all = 1;
     23	}
     24
     25	evsel = evsel__new_idx(attr, evlist->core.nr_entries);
     26	if (!evsel)
     27		return -1;
     28
     29	evsel->side_band.cb = cb;
     30	evsel->side_band.data = data;
     31	evlist__add(evlist, evsel);
     32	return 0;
     33}
     34
     35static void *perf_evlist__poll_thread(void *arg)
     36{
     37	struct evlist *evlist = arg;
     38	bool draining = false;
     39	int i, done = 0;
     40	/*
     41	 * In order to read symbols from other namespaces perf to needs to call
     42	 * setns(2).  This isn't permitted if the struct_fs has multiple users.
     43	 * unshare(2) the fs so that we may continue to setns into namespaces
     44	 * that we're observing when, for instance, reading the build-ids at
     45	 * the end of a 'perf record' session.
     46	 */
     47	unshare(CLONE_FS);
     48
     49	while (!done) {
     50		bool got_data = false;
     51
     52		if (evlist->thread.done)
     53			draining = true;
     54
     55		if (!draining)
     56			evlist__poll(evlist, 1000);
     57
     58		for (i = 0; i < evlist->core.nr_mmaps; i++) {
     59			struct mmap *map = &evlist->mmap[i];
     60			union perf_event *event;
     61
     62			if (perf_mmap__read_init(&map->core))
     63				continue;
     64			while ((event = perf_mmap__read_event(&map->core)) != NULL) {
     65				struct evsel *evsel = evlist__event2evsel(evlist, event);
     66
     67				if (evsel && evsel->side_band.cb)
     68					evsel->side_band.cb(event, evsel->side_band.data);
     69				else
     70					pr_warning("cannot locate proper evsel for the side band event\n");
     71
     72				perf_mmap__consume(&map->core);
     73				got_data = true;
     74			}
     75			perf_mmap__read_done(&map->core);
     76		}
     77
     78		if (draining && !got_data)
     79			break;
     80	}
     81	return NULL;
     82}
     83
     84void evlist__set_cb(struct evlist *evlist, evsel__sb_cb_t cb, void *data)
     85{
     86	struct evsel *evsel;
     87
     88	evlist__for_each_entry(evlist, evsel) {
     89		evsel->core.attr.sample_id_all    = 1;
     90		evsel->core.attr.watermark        = 1;
     91		evsel->core.attr.wakeup_watermark = 1;
     92		evsel->side_band.cb   = cb;
     93		evsel->side_band.data = data;
     94      }
     95}
     96
     97int evlist__start_sb_thread(struct evlist *evlist, struct target *target)
     98{
     99	struct evsel *counter;
    100
    101	if (!evlist)
    102		return 0;
    103
    104	if (evlist__create_maps(evlist, target))
    105		goto out_delete_evlist;
    106
    107	if (evlist->core.nr_entries > 1) {
    108		bool can_sample_identifier = perf_can_sample_identifier();
    109
    110		evlist__for_each_entry(evlist, counter)
    111			evsel__set_sample_id(counter, can_sample_identifier);
    112
    113		evlist__set_id_pos(evlist);
    114	}
    115
    116	evlist__for_each_entry(evlist, counter) {
    117		if (evsel__open(counter, evlist->core.user_requested_cpus,
    118				evlist->core.threads) < 0)
    119			goto out_delete_evlist;
    120	}
    121
    122	if (evlist__mmap(evlist, UINT_MAX))
    123		goto out_delete_evlist;
    124
    125	evlist__for_each_entry(evlist, counter) {
    126		if (evsel__enable(counter))
    127			goto out_delete_evlist;
    128	}
    129
    130	evlist->thread.done = 0;
    131	if (pthread_create(&evlist->thread.th, NULL, perf_evlist__poll_thread, evlist))
    132		goto out_delete_evlist;
    133
    134	return 0;
    135
    136out_delete_evlist:
    137	evlist__delete(evlist);
    138	evlist = NULL;
    139	return -1;
    140}
    141
    142void evlist__stop_sb_thread(struct evlist *evlist)
    143{
    144	if (!evlist)
    145		return;
    146	evlist->thread.done = 1;
    147	pthread_join(evlist->thread.th, NULL);
    148	evlist__delete(evlist);
    149}