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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright 2018 IBM Corporation.
*/
#define __SANE_USERSPACE_TYPES__
#include <sys/types.h>
#include <stdint.h>
#include <malloc.h>
#include <unistd.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "utils.h"
#include "flush_utils.h"
int entry_flush_test(void)
{
char *p;
int repetitions = 10;
int fd, passes = 0, iter, rc = 0;
struct perf_event_read v;
__u64 l1d_misses_total = 0;
unsigned long iterations = 100000, zero_size = 24 * 1024;
unsigned long l1d_misses_expected;
int rfi_flush_orig;
int entry_flush, entry_flush_orig;
SKIP_IF(geteuid() != 0);
// The PMU event we use only works on Power7 or later
SKIP_IF(!have_hwcap(PPC_FEATURE_ARCH_2_06));
if (read_debugfs_file("powerpc/rfi_flush", &rfi_flush_orig) < 0) {
perror("Unable to read powerpc/rfi_flush debugfs file");
SKIP_IF(1);
}
if (read_debugfs_file("powerpc/entry_flush", &entry_flush_orig) < 0) {
perror("Unable to read powerpc/entry_flush debugfs file");
SKIP_IF(1);
}
if (rfi_flush_orig != 0) {
if (write_debugfs_file("powerpc/rfi_flush", 0) < 0) {
perror("error writing to powerpc/rfi_flush debugfs file");
FAIL_IF(1);
}
}
entry_flush = entry_flush_orig;
fd = perf_event_open_counter(PERF_TYPE_HW_CACHE, PERF_L1D_READ_MISS_CONFIG, -1);
FAIL_IF(fd < 0);
p = (char *)memalign(zero_size, CACHELINE_SIZE);
FAIL_IF(perf_event_enable(fd));
// disable L1 prefetching
set_dscr(1);
iter = repetitions;
/*
* We expect to see l1d miss for each cacheline access when entry_flush
* is set. Allow a small variation on this.
*/
l1d_misses_expected = iterations * (zero_size / CACHELINE_SIZE - 2);
again:
FAIL_IF(perf_event_reset(fd));
syscall_loop(p, iterations, zero_size);
FAIL_IF(read(fd, &v, sizeof(v)) != sizeof(v));
if (entry_flush && v.l1d_misses >= l1d_misses_expected)
passes++;
else if (!entry_flush && v.l1d_misses < (l1d_misses_expected / 2))
passes++;
l1d_misses_total += v.l1d_misses;
while (--iter)
goto again;
if (passes < repetitions) {
printf("FAIL (L1D misses with entry_flush=%d: %llu %c %lu) [%d/%d failures]\n",
entry_flush, l1d_misses_total, entry_flush ? '<' : '>',
entry_flush ? repetitions * l1d_misses_expected :
repetitions * l1d_misses_expected / 2,
repetitions - passes, repetitions);
rc = 1;
} else {
printf("PASS (L1D misses with entry_flush=%d: %llu %c %lu) [%d/%d pass]\n",
entry_flush, l1d_misses_total, entry_flush ? '>' : '<',
entry_flush ? repetitions * l1d_misses_expected :
repetitions * l1d_misses_expected / 2,
passes, repetitions);
}
if (entry_flush == entry_flush_orig) {
entry_flush = !entry_flush_orig;
if (write_debugfs_file("powerpc/entry_flush", entry_flush) < 0) {
perror("error writing to powerpc/entry_flush debugfs file");
return 1;
}
iter = repetitions;
l1d_misses_total = 0;
passes = 0;
goto again;
}
perf_event_disable(fd);
close(fd);
set_dscr(0);
if (write_debugfs_file("powerpc/rfi_flush", rfi_flush_orig) < 0) {
perror("unable to restore original value of powerpc/rfi_flush debugfs file");
return 1;
}
if (write_debugfs_file("powerpc/entry_flush", entry_flush_orig) < 0) {
perror("unable to restore original value of powerpc/entry_flush debugfs file");
return 1;
}
return rc;
}
int main(int argc, char *argv[])
{
return test_harness(entry_flush_test, "entry_flush_test");
}
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