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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pmc56_overflow_test.c (1653B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Copyright 2014, Michael Ellerman, IBM Corp.
      4 */
      5
      6#include <stdio.h>
      7#include <stdlib.h>
      8
      9#include "ebb.h"
     10
     11
     12/*
     13 * Test that PMC5 & 6 are frozen (ie. don't overflow) when they are not being
     14 * used. Tests the MMCR0_FC56 logic in the kernel.
     15 */
     16
     17static int pmc56_overflowed;
     18
     19static void ebb_callee(void)
     20{
     21	uint64_t val;
     22
     23	val = mfspr(SPRN_BESCR);
     24	if (!(val & BESCR_PMEO)) {
     25		ebb_state.stats.spurious++;
     26		goto out;
     27	}
     28
     29	ebb_state.stats.ebb_count++;
     30	count_pmc(2, sample_period);
     31
     32	val = mfspr(SPRN_PMC5);
     33	if (val >= COUNTER_OVERFLOW)
     34		pmc56_overflowed++;
     35
     36	count_pmc(5, COUNTER_OVERFLOW);
     37
     38	val = mfspr(SPRN_PMC6);
     39	if (val >= COUNTER_OVERFLOW)
     40		pmc56_overflowed++;
     41
     42	count_pmc(6, COUNTER_OVERFLOW);
     43
     44out:
     45	reset_ebb();
     46}
     47
     48int pmc56_overflow(void)
     49{
     50	struct event event;
     51
     52	SKIP_IF(!ebb_is_supported());
     53
     54	/* Use PMC2 so we set PMCjCE, which enables PMC5/6 */
     55	event_init(&event, 0x2001e);
     56	event_leader_ebb_init(&event);
     57
     58	event.attr.exclude_kernel = 1;
     59	event.attr.exclude_hv = 1;
     60	event.attr.exclude_idle = 1;
     61
     62	FAIL_IF(event_open(&event));
     63
     64	setup_ebb_handler(ebb_callee);
     65	ebb_global_enable();
     66
     67	FAIL_IF(ebb_event_enable(&event));
     68
     69	mtspr(SPRN_PMC2, pmc_sample_period(sample_period));
     70	mtspr(SPRN_PMC5, 0);
     71	mtspr(SPRN_PMC6, 0);
     72
     73	while (ebb_state.stats.ebb_count < 10)
     74		FAIL_IF(core_busy_loop());
     75
     76	ebb_global_disable();
     77	ebb_freeze_pmcs();
     78
     79	dump_ebb_state();
     80
     81	printf("PMC5/6 overflow %d\n", pmc56_overflowed);
     82
     83	event_close(&event);
     84
     85	FAIL_IF(ebb_state.stats.ebb_count == 0 || pmc56_overflowed != 0);
     86
     87	return 0;
     88}
     89
     90int main(void)
     91{
     92	return test_harness(pmc56_overflow, "pmc56_overflow");
     93}