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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topdown.c (1656B)

      1// SPDX-License-Identifier: GPL-2.0
      2#include <stdio.h>
      3#include "api/fs/fs.h"
      4#include "util/pmu.h"
      5#include "util/topdown.h"
      6#include "topdown.h"
      7#include "evsel.h"
      8
      9/* Check whether there is a PMU which supports the perf metrics. */
     10bool topdown_sys_has_perf_metrics(void)
     11{
     12	static bool has_perf_metrics;
     13	static bool cached;
     14	struct perf_pmu *pmu;
     15
     16	if (cached)
     17		return has_perf_metrics;
     18
     19	/*
     20	 * The perf metrics feature is a core PMU feature.
     21	 * The PERF_TYPE_RAW type is the type of a core PMU.
     22	 * The slots event is only available when the core PMU
     23	 * supports the perf metrics feature.
     24	 */
     25	pmu = perf_pmu__find_by_type(PERF_TYPE_RAW);
     26	if (pmu && pmu_have_event(pmu->name, "slots"))
     27		has_perf_metrics = true;
     28
     29	cached = true;
     30	return has_perf_metrics;
     31}
     32
     33/*
     34 * Check whether we can use a group for top down.
     35 * Without a group may get bad results due to multiplexing.
     36 */
     37bool arch_topdown_check_group(bool *warn)
     38{
     39	int n;
     40
     41	if (sysctl__read_int("kernel/nmi_watchdog", &n) < 0)
     42		return false;
     43	if (n > 0) {
     44		*warn = true;
     45		return false;
     46	}
     47	return true;
     48}
     49
     50void arch_topdown_group_warn(void)
     51{
     52	fprintf(stderr,
     53		"nmi_watchdog enabled with topdown. May give wrong results.\n"
     54		"Disable with echo 0 > /proc/sys/kernel/nmi_watchdog\n");
     55}
     56
     57#define TOPDOWN_SLOTS		0x0400
     58
     59/*
     60 * Check whether a topdown group supports sample-read.
     61 *
     62 * Only Topdown metric supports sample-read. The slots
     63 * event must be the leader of the topdown group.
     64 */
     65
     66bool arch_topdown_sample_read(struct evsel *leader)
     67{
     68	if (!evsel__sys_has_perf_metrics(leader))
     69		return false;
     70
     71	if (leader->core.attr.config == TOPDOWN_SLOTS)
     72		return true;
     73
     74	return false;
     75}