tools/perf/tests/bpf.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <errno.h>
   3 #include <stdio.h>
   4 #include <sys/epoll.h>
   5 #include <sys/types.h>
   6 #include <sys/stat.h>
   7 #include <fcntl.h>
   8 #include <util/record.h>
   9 #include <util/util.h>
  10 #include <util/bpf-loader.h>
  11 #include <util/evlist.h>
  12 #include <linux/filter.h>
  13 #include <linux/kernel.h>
  14 #include <linux/string.h>
  15 #include <api/fs/fs.h>
  16 #include <perf/mmap.h>
  17 #include "tests.h"
  18 #include "llvm.h"
  19 #include "debug.h"
  20 #include "parse-events.h"
  21 #include "util/mmap.h"
  22 #define NR_ITERS       111
  23 #define PERF_TEST_BPF_PATH "/sys/fs/bpf/perf_test"
  24
  25 #ifdef HAVE_LIBBPF_SUPPORT
  26 #include <linux/bpf.h>
  27 #include <bpf/bpf.h>
  28
  29 static int epoll_pwait_loop(void)
  30 {
  31         int i;
  32
  33         /* Should fail NR_ITERS times */
  34         for (i = 0; i < NR_ITERS; i++)
  35                 epoll_pwait(-(i + 1), NULL, 0, 0, NULL);
  36         return 0;
  37 }
  38
  39 #ifdef HAVE_BPF_PROLOGUE
  40
  41 static int llseek_loop(void)
  42 {
  43         int fds[2], i;
  44
  45         fds[0] = open("/dev/null", O_RDONLY);
  46         fds[1] = open("/dev/null", O_RDWR);
  47
  48         if (fds[0] < 0 || fds[1] < 0)
  49                 return -1;
  50
  51         for (i = 0; i < NR_ITERS; i++) {
  52                 lseek(fds[i % 2], i, (i / 2) % 2 ? SEEK_CUR : SEEK_SET);
  53                 lseek(fds[(i + 1) % 2], i, (i / 2) % 2 ? SEEK_CUR : SEEK_SET);
  54         }
  55         close(fds[0]);
  56         close(fds[1]);
  57         return 0;
  58 }
  59
  60 #endif
  61
  62 static struct {
  63         enum test_llvm__testcase prog_id;
  64         const char *desc;
  65         const char *name;
  66         const char *msg_compile_fail;
  67         const char *msg_load_fail;
  68         int (*target_func)(void);
  69         int expect_result;
  70         bool    pin;
  71 } bpf_testcase_table[] = {
  72         {
  73                 .prog_id          = LLVM_TESTCASE_BASE,
  74                 .desc             = "Basic BPF filtering",
  75                 .name             = "[basic_bpf_test]",
  76                 .msg_compile_fail = "fix 'perf test LLVM' first",
  77                 .msg_load_fail    = "load bpf object failed",
  78                 .target_func      = &epoll_pwait_loop,
  79                 .expect_result    = (NR_ITERS + 1) / 2,
  80         },
  81         {
  82                 .prog_id          = LLVM_TESTCASE_BASE,
  83                 .desc             = "BPF pinning",
  84                 .name             = "[bpf_pinning]",
  85                 .msg_compile_fail = "fix kbuild first",
  86                 .msg_load_fail    = "check your vmlinux setting?",
  87                 .target_func      = &epoll_pwait_loop,
  88                 .expect_result    = (NR_ITERS + 1) / 2,
  89                 .pin              = true,
  90         },
  91 #ifdef HAVE_BPF_PROLOGUE
  92         {
  93                 .prog_id          = LLVM_TESTCASE_BPF_PROLOGUE,
  94                 .desc             = "BPF prologue generation",
  95                 .name             = "[bpf_prologue_test]",
  96                 .msg_compile_fail = "fix kbuild first",
  97                 .msg_load_fail    = "check your vmlinux setting?",
  98                 .target_func      = &llseek_loop,
  99                 .expect_result    = (NR_ITERS + 1) / 4,
 100         },
 101 #endif
 102 };
 103
 104 static int do_test(struct bpf_object *obj, int (*func)(void),
 105                    int expect)
 106 {
 107         struct record_opts opts = {
 108                 .target = {
 109                         .uid = UINT_MAX,
 110                         .uses_mmap = true,
 111                 },
 112                 .freq         = 0,
 113                 .mmap_pages   = 256,
 114                 .default_interval = 1,
 115         };
 116
 117         char pid[16];
 118         char sbuf[STRERR_BUFSIZE];
 119         struct evlist *evlist;
 120         int i, ret = TEST_FAIL, err = 0, count = 0;
 121
 122         struct parse_events_state parse_state;
 123         struct parse_events_error parse_error;
 124
 125         bzero(&parse_error, sizeof(parse_error));
 126         bzero(&parse_state, sizeof(parse_state));
 127         parse_state.error = &parse_error;
 128         INIT_LIST_HEAD(&parse_state.list);
 129
 130         err = parse_events_load_bpf_obj(&parse_state, &parse_state.list, obj, NULL);
 131         if (err || list_empty(&parse_state.list)) {
 132                 pr_debug("Failed to add events selected by BPF\n");
 133                 return TEST_FAIL;
 134         }
 135
 136         snprintf(pid, sizeof(pid), "%d", getpid());
 137         pid[sizeof(pid) - 1] = '\0';
 138         opts.target.tid = opts.target.pid = pid;
 139
 140         /* Instead of evlist__new_default, don't add default events */
 141         evlist = evlist__new();
 142         if (!evlist) {
 143                 pr_debug("Not enough memory to create evlist\n");
 144                 return TEST_FAIL;
 145         }
 146
 147         err = evlist__create_maps(evlist, &opts.target);
 148         if (err < 0) {
 149                 pr_debug("Not enough memory to create thread/cpu maps\n");
 150                 goto out_delete_evlist;
 151         }
 152
 153         evlist__splice_list_tail(evlist, &parse_state.list);
 154         evlist->nr_groups = parse_state.nr_groups;
 155
 156         evlist__config(evlist, &opts, NULL);
 157
 158         err = evlist__open(evlist);
 159         if (err < 0) {
 160                 pr_debug("perf_evlist__open: %s\n",
 161                          str_error_r(errno, sbuf, sizeof(sbuf)));
 162                 goto out_delete_evlist;
 163         }
 164
 165         err = evlist__mmap(evlist, opts.mmap_pages);
 166         if (err < 0) {
 167                 pr_debug("evlist__mmap: %s\n",
 168                          str_error_r(errno, sbuf, sizeof(sbuf)));
 169                 goto out_delete_evlist;
 170         }
 171
 172         evlist__enable(evlist);
 173         (*func)();
 174         evlist__disable(evlist);
 175
 176         for (i = 0; i < evlist->core.nr_mmaps; i++) {
 177                 union perf_event *event;
 178                 struct mmap *md;
 179
 180                 md = &evlist->mmap[i];
 181                 if (perf_mmap__read_init(&md->core) < 0)
 182                         continue;
 183
 184                 while ((event = perf_mmap__read_event(&md->core)) != NULL) {
 185                         const u32 type = event->header.type;
 186
 187                         if (type == PERF_RECORD_SAMPLE)
 188                                 count ++;
 189                 }
 190                 perf_mmap__read_done(&md->core);
 191         }
 192
 193         if (count != expect * evlist->core.nr_entries) {
 194                 pr_debug("BPF filter result incorrect, expected %d, got %d samples\n", expect, count);
 195                 goto out_delete_evlist;
 196         }
 197
 198         ret = TEST_OK;
 199
 200 out_delete_evlist:
 201         evlist__delete(evlist);
 202         return ret;
 203 }
 204
 205 static struct bpf_object *
 206 prepare_bpf(void *obj_buf, size_t obj_buf_sz, const char *name)
 207 {
 208         struct bpf_object *obj;
 209
 210         obj = bpf__prepare_load_buffer(obj_buf, obj_buf_sz, name);
 211         if (IS_ERR(obj)) {
 212                 pr_debug("Compile BPF program failed.\n");
 213                 return NULL;
 214         }
 215         return obj;
 216 }
 217
 218 static int __test__bpf(int idx)
 219 {
 220         int ret;
 221         void *obj_buf;
 222         size_t obj_buf_sz;
 223         struct bpf_object *obj;
 224
 225         ret = test_llvm__fetch_bpf_obj(&obj_buf, &obj_buf_sz,
 226                                        bpf_testcase_table[idx].prog_id,
 227                                        true, NULL);
 228         if (ret != TEST_OK || !obj_buf || !obj_buf_sz) {
 229                 pr_debug("Unable to get BPF object, %s\n",
 230                          bpf_testcase_table[idx].msg_compile_fail);
 231                 if (idx == 0)
 232                         return TEST_SKIP;
 233                 else
 234                         return TEST_FAIL;
 235         }
 236
 237         obj = prepare_bpf(obj_buf, obj_buf_sz,
 238                           bpf_testcase_table[idx].name);
 239         if ((!!bpf_testcase_table[idx].target_func) != (!!obj)) {
 240                 if (!obj)
 241                         pr_debug("Fail to load BPF object: %s\n",
 242                                  bpf_testcase_table[idx].msg_load_fail);
 243                 else
 244                         pr_debug("Success unexpectedly: %s\n",
 245                                  bpf_testcase_table[idx].msg_load_fail);
 246                 ret = TEST_FAIL;
 247                 goto out;
 248         }
 249
 250         if (obj) {
 251                 ret = do_test(obj,
 252                               bpf_testcase_table[idx].target_func,
 253                               bpf_testcase_table[idx].expect_result);
 254                 if (ret != TEST_OK)
 255                         goto out;
 256                 if (bpf_testcase_table[idx].pin) {
 257                         int err;
 258
 259                         if (!bpf_fs__mount()) {
 260                                 pr_debug("BPF filesystem not mounted\n");
 261                                 ret = TEST_FAIL;
 262                                 goto out;
 263                         }
 264                         err = mkdir(PERF_TEST_BPF_PATH, 0777);
 265                         if (err && errno != EEXIST) {
 266                                 pr_debug("Failed to make perf_test dir: %s\n",
 267                                          strerror(errno));
 268                                 ret = TEST_FAIL;
 269                                 goto out;
 270                         }
 271                         if (bpf_object__pin(obj, PERF_TEST_BPF_PATH))
 272                                 ret = TEST_FAIL;
 273                         if (rm_rf(PERF_TEST_BPF_PATH))
 274                                 ret = TEST_FAIL;
 275                 }
 276         }
 277
 278 out:
 279         bpf__clear();
 280         return ret;
 281 }
 282
 283 int test__bpf_subtest_get_nr(void)
 284 {
 285         return (int)ARRAY_SIZE(bpf_testcase_table);
 286 }
 287
 288 const char *test__bpf_subtest_get_desc(int i)
 289 {
 290         if (i < 0 || i >= (int)ARRAY_SIZE(bpf_testcase_table))
 291                 return NULL;
 292         return bpf_testcase_table[i].desc;
 293 }
 294
 295 static int check_env(void)
 296 {
 297         int err;
 298         unsigned int kver_int;
 299         char license[] = "GPL";
 300
 301         struct bpf_insn insns[] = {
 302                 BPF_MOV64_IMM(BPF_REG_0, 1),
 303                 BPF_EXIT_INSN(),
 304         };
 305
 306         err = fetch_kernel_version(&kver_int, NULL, 0);
 307         if (err) {
 308                 pr_debug("Unable to get kernel version\n");
 309                 return err;
 310         }
 311
 312         err = bpf_load_program(BPF_PROG_TYPE_KPROBE, insns,
 313                                sizeof(insns) / sizeof(insns[0]),
 314                                license, kver_int, NULL, 0);
 315         if (err < 0) {
 316                 pr_err("Missing basic BPF support, skip this test: %s\n",
 317                        strerror(errno));
 318                 return err;
 319         }
 320         close(err);
 321
 322         return 0;
 323 }
 324
 325 int test__bpf(struct test *test __maybe_unused, int i)
 326 {
 327         int err;
 328
 329         if (i < 0 || i >= (int)ARRAY_SIZE(bpf_testcase_table))
 330                 return TEST_FAIL;
 331
 332         if (geteuid() != 0) {
 333                 pr_debug("Only root can run BPF test\n");
 334                 return TEST_SKIP;
 335         }
 336
 337         if (check_env())
 338                 return TEST_SKIP;
 339
 340         err = __test__bpf(i);
 341         return err;
 342 }
 343
 344 #else
 345 int test__bpf_subtest_get_nr(void)
 346 {
 347         return 0;
 348 }
 349
 350 const char *test__bpf_subtest_get_desc(int i __maybe_unused)
 351 {
 352         return NULL;
 353 }
 354
 355 int test__bpf(struct test *test __maybe_unused, int i __maybe_unused)
 356 {
 357         pr_debug("Skip BPF test because BPF support is not compiled\n");
 358         return TEST_SKIP;
 359 }
 360 #endif