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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entry_flush.c (3486B)

      1// SPDX-License-Identifier: GPL-2.0+
      2
      3/*
      4 * Copyright 2018 IBM Corporation.
      5 */
      6
      7#define __SANE_USERSPACE_TYPES__
      8
      9#include <sys/types.h>
     10#include <stdint.h>
     11#include <malloc.h>
     12#include <unistd.h>
     13#include <signal.h>
     14#include <stdlib.h>
     15#include <string.h>
     16#include <stdio.h>
     17#include "utils.h"
     18#include "flush_utils.h"
     19
     20int entry_flush_test(void)
     21{
     22	char *p;
     23	int repetitions = 10;
     24	int fd, passes = 0, iter, rc = 0;
     25	struct perf_event_read v;
     26	__u64 l1d_misses_total = 0;
     27	unsigned long iterations = 100000, zero_size = 24 * 1024;
     28	unsigned long l1d_misses_expected;
     29	int rfi_flush_orig;
     30	int entry_flush, entry_flush_orig;
     31
     32	SKIP_IF(geteuid() != 0);
     33
     34	// The PMU event we use only works on Power7 or later
     35	SKIP_IF(!have_hwcap(PPC_FEATURE_ARCH_2_06));
     36
     37	if (read_debugfs_file("powerpc/rfi_flush", &rfi_flush_orig) < 0) {
     38		perror("Unable to read powerpc/rfi_flush debugfs file");
     39		SKIP_IF(1);
     40	}
     41
     42	if (read_debugfs_file("powerpc/entry_flush", &entry_flush_orig) < 0) {
     43		perror("Unable to read powerpc/entry_flush debugfs file");
     44		SKIP_IF(1);
     45	}
     46
     47	if (rfi_flush_orig != 0) {
     48		if (write_debugfs_file("powerpc/rfi_flush", 0) < 0) {
     49			perror("error writing to powerpc/rfi_flush debugfs file");
     50			FAIL_IF(1);
     51		}
     52	}
     53
     54	entry_flush = entry_flush_orig;
     55
     56	fd = perf_event_open_counter(PERF_TYPE_HW_CACHE, PERF_L1D_READ_MISS_CONFIG, -1);
     57	FAIL_IF(fd < 0);
     58
     59	p = (char *)memalign(zero_size, CACHELINE_SIZE);
     60
     61	FAIL_IF(perf_event_enable(fd));
     62
     63	// disable L1 prefetching
     64	set_dscr(1);
     65
     66	iter = repetitions;
     67
     68	/*
     69	 * We expect to see l1d miss for each cacheline access when entry_flush
     70	 * is set. Allow a small variation on this.
     71	 */
     72	l1d_misses_expected = iterations * (zero_size / CACHELINE_SIZE - 2);
     73
     74again:
     75	FAIL_IF(perf_event_reset(fd));
     76
     77	syscall_loop(p, iterations, zero_size);
     78
     79	FAIL_IF(read(fd, &v, sizeof(v)) != sizeof(v));
     80
     81	if (entry_flush && v.l1d_misses >= l1d_misses_expected)
     82		passes++;
     83	else if (!entry_flush && v.l1d_misses < (l1d_misses_expected / 2))
     84		passes++;
     85
     86	l1d_misses_total += v.l1d_misses;
     87
     88	while (--iter)
     89		goto again;
     90
     91	if (passes < repetitions) {
     92		printf("FAIL (L1D misses with entry_flush=%d: %llu %c %lu) [%d/%d failures]\n",
     93		       entry_flush, l1d_misses_total, entry_flush ? '<' : '>',
     94		       entry_flush ? repetitions * l1d_misses_expected :
     95		       repetitions * l1d_misses_expected / 2,
     96		       repetitions - passes, repetitions);
     97		rc = 1;
     98	} else {
     99		printf("PASS (L1D misses with entry_flush=%d: %llu %c %lu) [%d/%d pass]\n",
    100		       entry_flush, l1d_misses_total, entry_flush ? '>' : '<',
    101		       entry_flush ? repetitions * l1d_misses_expected :
    102		       repetitions * l1d_misses_expected / 2,
    103		       passes, repetitions);
    104	}
    105
    106	if (entry_flush == entry_flush_orig) {
    107		entry_flush = !entry_flush_orig;
    108		if (write_debugfs_file("powerpc/entry_flush", entry_flush) < 0) {
    109			perror("error writing to powerpc/entry_flush debugfs file");
    110			return 1;
    111		}
    112		iter = repetitions;
    113		l1d_misses_total = 0;
    114		passes = 0;
    115		goto again;
    116	}
    117
    118	perf_event_disable(fd);
    119	close(fd);
    120
    121	set_dscr(0);
    122
    123	if (write_debugfs_file("powerpc/rfi_flush", rfi_flush_orig) < 0) {
    124		perror("unable to restore original value of powerpc/rfi_flush debugfs file");
    125		return 1;
    126	}
    127
    128	if (write_debugfs_file("powerpc/entry_flush", entry_flush_orig) < 0) {
    129		perror("unable to restore original value of powerpc/entry_flush debugfs file");
    130		return 1;
    131	}
    132
    133	return rc;
    134}
    135
    136int main(int argc, char *argv[])
    137{
    138	return test_harness(entry_flush_test, "entry_flush_test");
    139}