140 lines · c
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 later35 SKIP_IF(!have_hwcap(PPC_FEATURE_ARCH_2_06));36 37 if (read_debugfs_int("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_int("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_int("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 prefetching64 set_dscr(1);65 66 iter = repetitions;67 68 /*69 * We expect to see l1d miss for each cacheline access when entry_flush70 * 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_int("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_int("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_int("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}140