tools/perf/tests/bpf.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <errno.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <sys/epoll.h>
   6 #include <sys/types.h>
   7 #include <sys/stat.h>
   8 #include <fcntl.h>
   9 #include <util/record.h>
  10 #include <util/util.h>
  11 #include <util/bpf-loader.h>
  12 #include <util/evlist.h>
  13 #include <linux/bpf.h>
  14 #include <linux/filter.h>
  15 #include <linux/kernel.h>
  16 #include <linux/string.h>
  17 #include <api/fs/fs.h>
  18 #include <bpf/bpf.h>
  19 #include <perf/mmap.h>
  20 #include "tests.h"
  21 #include "llvm.h"
  22 #include "debug.h"
  23 #include "parse-events.h"
  24 #include "util/mmap.h"
  25 #define NR_ITERS       111
  26 #define PERF_TEST_BPF_PATH "/sys/fs/bpf/perf_test"
  27
  28 #ifdef HAVE_LIBBPF_SUPPORT
  29
  30 static int epoll_pwait_loop(void)
  31 {
  32         int i;
  33
  34         /* Should fail NR_ITERS times */
  35         for (i = 0; i < NR_ITERS; i++)
  36                 epoll_pwait(-(i + 1), NULL, 0, 0, NULL);
  37         return 0;
  38 }
  39
  40 #ifdef HAVE_BPF_PROLOGUE
  41
  42 static int llseek_loop(void)
  43 {
  44         int fds[2], i;
  45
  46         fds[0] = open("/dev/null", O_RDONLY);
  47         fds[1] = open("/dev/null", O_RDWR);
  48
  49         if (fds[0] < 0 || fds[1] < 0)
  50                 return -1;
  51
  52         for (i = 0; i < NR_ITERS; i++) {
  53                 lseek(fds[i % 2], i, (i / 2) % 2 ? SEEK_CUR : SEEK_SET);
  54                 lseek(fds[(i + 1) % 2], i, (i / 2) % 2 ? SEEK_CUR : SEEK_SET);
  55         }
  56         close(fds[0]);
  57         close(fds[1]);
  58         return 0;
  59 }
  60
  61 #endif
  62
  63 static struct {
  64         enum test_llvm__testcase prog_id;
  65         const char *desc;
  66         const char *name;
  67         const char *msg_compile_fail;
  68         const char *msg_load_fail;
  69         int (*target_func)(void);
  70         int expect_result;
  71         bool    pin;
  72 } bpf_testcase_table[] = {
  73         {
  74                 .prog_id          = LLVM_TESTCASE_BASE,
  75                 .desc             = "Basic BPF filtering",
  76                 .name             = "[basic_bpf_test]",
  77                 .msg_compile_fail = "fix 'perf test LLVM' first",
  78                 .msg_load_fail    = "load bpf object failed",
  79                 .target_func      = &epoll_pwait_loop,
  80                 .expect_result    = (NR_ITERS + 1) / 2,
  81         },
  82         {
  83                 .prog_id          = LLVM_TESTCASE_BASE,
  84                 .desc             = "BPF pinning",
  85                 .name             = "[bpf_pinning]",
  86                 .msg_compile_fail = "fix kbuild first",
  87                 .msg_load_fail    = "check your vmlinux setting?",
  88                 .target_func      = &epoll_pwait_loop,
  89                 .expect_result    = (NR_ITERS + 1) / 2,
  90                 .pin              = true,
  91         },
  92 #ifdef HAVE_BPF_PROLOGUE
  93         {
  94                 .prog_id          = LLVM_TESTCASE_BPF_PROLOGUE,
  95                 .desc             = "BPF prologue generation",
  96                 .name             = "[bpf_prologue_test]",
  97                 .msg_compile_fail = "fix kbuild first",
  98                 .msg_load_fail    = "check your vmlinux setting?",
  99                 .target_func      = &llseek_loop,
 100                 .expect_result    = (NR_ITERS + 1) / 4,
 101         },
 102 #endif
 103         {
 104                 .prog_id          = LLVM_TESTCASE_BPF_RELOCATION,
 105                 .desc             = "BPF relocation checker",
 106                 .name             = "[bpf_relocation_test]",
 107                 .msg_compile_fail = "fix 'perf test LLVM' first",
 108                 .msg_load_fail    = "libbpf error when dealing with relocation",
 109         },
 110 };
 111
 112 static int do_test(struct bpf_object *obj, int (*func)(void),
 113                    int expect)
 114 {
 115         struct record_opts opts = {
 116                 .target = {
 117                         .uid = UINT_MAX,
 118                         .uses_mmap = true,
 119                 },
 120                 .freq         = 0,
 121                 .mmap_pages   = 256,
 122                 .default_interval = 1,
 123         };
 124
 125         char pid[16];
 126         char sbuf[STRERR_BUFSIZE];
 127         struct evlist *evlist;
 128         int i, ret = TEST_FAIL, err = 0, count = 0;
 129
 130         struct parse_events_state parse_state;
 131         struct parse_events_error parse_error;
 132
 133         bzero(&parse_error, sizeof(parse_error));
 134         bzero(&parse_state, sizeof(parse_state));
 135         parse_state.error = &parse_error;
 136         INIT_LIST_HEAD(&parse_state.list);
 137
 138         err = parse_events_load_bpf_obj(&parse_state, &parse_state.list, obj, NULL);
 139         if (err || list_empty(&parse_state.list)) {
 140                 pr_debug("Failed to add events selected by BPF\n");
 141                 return TEST_FAIL;
 142         }
 143
 144         snprintf(pid, sizeof(pid), "%d", getpid());
 145         pid[sizeof(pid) - 1] = '\0';
 146         opts.target.tid = opts.target.pid = pid;
 147
 148         /* Instead of perf_evlist__new_default, don't add default events */
 149         evlist = evlist__new();
 150         if (!evlist) {
 151                 pr_debug("Not enough memory to create evlist\n");
 152                 return TEST_FAIL;
 153         }
 154
 155         err = perf_evlist__create_maps(evlist, &opts.target);
 156         if (err < 0) {
 157                 pr_debug("Not enough memory to create thread/cpu maps\n");
 158                 goto out_delete_evlist;
 159         }
 160
 161         perf_evlist__splice_list_tail(evlist, &parse_state.list);
 162         evlist->nr_groups = parse_state.nr_groups;
 163
 164         perf_evlist__config(evlist, &opts, NULL);
 165
 166         err = evlist__open(evlist);
 167         if (err < 0) {
 168                 pr_debug("perf_evlist__open: %s\n",
 169                          str_error_r(errno, sbuf, sizeof(sbuf)));
 170                 goto out_delete_evlist;
 171         }
 172
 173         err = evlist__mmap(evlist, opts.mmap_pages);
 174         if (err < 0) {
 175                 pr_debug("evlist__mmap: %s\n",
 176                          str_error_r(errno, sbuf, sizeof(sbuf)));
 177                 goto out_delete_evlist;
 178         }
 179
 180         evlist__enable(evlist);
 181         (*func)();
 182         evlist__disable(evlist);
 183
 184         for (i = 0; i < evlist->core.nr_mmaps; i++) {
 185                 union perf_event *event;
 186                 struct mmap *md;
 187
 188                 md = &evlist->mmap[i];
 189                 if (perf_mmap__read_init(&md->core) < 0)
 190                         continue;
 191
 192                 while ((event = perf_mmap__read_event(&md->core)) != NULL) {
 193                         const u32 type = event->header.type;
 194
 195                         if (type == PERF_RECORD_SAMPLE)
 196                                 count ++;
 197                 }
 198                 perf_mmap__read_done(&md->core);
 199         }
 200
 201         if (count != expect * evlist->core.nr_entries) {
 202                 pr_debug("BPF filter result incorrect, expected %d, got %d samples\n", expect * evlist->core.nr_entries, count);
 203                 goto out_delete_evlist;
 204         }
 205
 206         ret = TEST_OK;
 207
 208 out_delete_evlist:
 209         evlist__delete(evlist);
 210         return ret;
 211 }
 212
 213 static struct bpf_object *
 214 prepare_bpf(void *obj_buf, size_t obj_buf_sz, const char *name)
 215 {
 216         struct bpf_object *obj;
 217
 218         obj = bpf__prepare_load_buffer(obj_buf, obj_buf_sz, name);
 219         if (IS_ERR(obj)) {
 220                 pr_debug("Compile BPF program failed.\n");
 221                 return NULL;
 222         }
 223         return obj;
 224 }
 225
 226 static int __test__bpf(int idx)
 227 {
 228         int ret;
 229         void *obj_buf;
 230         size_t obj_buf_sz;
 231         struct bpf_object *obj;
 232
 233         ret = test_llvm__fetch_bpf_obj(&obj_buf, &obj_buf_sz,
 234                                        bpf_testcase_table[idx].prog_id,
 235                                        true, NULL);
 236         if (ret != TEST_OK || !obj_buf || !obj_buf_sz) {
 237                 pr_debug("Unable to get BPF object, %s\n",
 238                          bpf_testcase_table[idx].msg_compile_fail);
 239                 if (idx == 0)
 240                         return TEST_SKIP;
 241                 else
 242                         return TEST_FAIL;
 243         }
 244
 245         obj = prepare_bpf(obj_buf, obj_buf_sz,
 246                           bpf_testcase_table[idx].name);
 247         if ((!!bpf_testcase_table[idx].target_func) != (!!obj)) {
 248                 if (!obj)
 249                         pr_debug("Fail to load BPF object: %s\n",
 250                                  bpf_testcase_table[idx].msg_load_fail);
 251                 else
 252                         pr_debug("Success unexpectedly: %s\n",
 253                                  bpf_testcase_table[idx].msg_load_fail);
 254                 ret = TEST_FAIL;
 255                 goto out;
 256         }
 257
 258         if (obj) {
 259                 ret = do_test(obj,
 260                               bpf_testcase_table[idx].target_func,
 261                               bpf_testcase_table[idx].expect_result);
 262                 if (ret != TEST_OK)
 263                         goto out;
 264                 if (bpf_testcase_table[idx].pin) {
 265                         int err;
 266
 267                         if (!bpf_fs__mount()) {
 268                                 pr_debug("BPF filesystem not mounted\n");
 269                                 ret = TEST_FAIL;
 270                                 goto out;
 271                         }
 272                         err = mkdir(PERF_TEST_BPF_PATH, 0777);
 273                         if (err && errno != EEXIST) {
 274                                 pr_debug("Failed to make perf_test dir: %s\n",
 275                                          strerror(errno));
 276                                 ret = TEST_FAIL;
 277                                 goto out;
 278                         }
 279                         if (bpf_object__pin(obj, PERF_TEST_BPF_PATH))
 280                                 ret = TEST_FAIL;
 281                         if (rm_rf(PERF_TEST_BPF_PATH))
 282                                 ret = TEST_FAIL;
 283                 }
 284         }
 285
 286 out:
 287         free(obj_buf);
 288         bpf__clear();
 289         return ret;
 290 }
 291
 292 int test__bpf_subtest_get_nr(void)
 293 {
 294         return (int)ARRAY_SIZE(bpf_testcase_table);
 295 }
 296
 297 const char *test__bpf_subtest_get_desc(int i)
 298 {
 299         if (i < 0 || i >= (int)ARRAY_SIZE(bpf_testcase_table))
 300                 return NULL;
 301         return bpf_testcase_table[i].desc;
 302 }
 303
 304 static int check_env(void)
 305 {
 306         int err;
 307         unsigned int kver_int;
 308         char license[] = "GPL";
 309
 310         struct bpf_insn insns[] = {
 311                 BPF_MOV64_IMM(BPF_REG_0, 1),
 312                 BPF_EXIT_INSN(),
 313         };
 314
 315         err = fetch_kernel_version(&kver_int, NULL, 0);
 316         if (err) {
 317                 pr_debug("Unable to get kernel version\n");
 318                 return err;
 319         }
 320
 321         err = bpf_load_program(BPF_PROG_TYPE_KPROBE, insns,
 322                                sizeof(insns) / sizeof(insns[0]),
 323                                license, kver_int, NULL, 0);
 324         if (err < 0) {
 325                 pr_err("Missing basic BPF support, skip this test: %s\n",
 326                        strerror(errno));
 327                 return err;
 328         }
 329         close(err);
 330
 331         return 0;
 332 }
 333
 334 int test__bpf(struct test *test __maybe_unused, int i)
 335 {
 336         int err;
 337
 338         if (i < 0 || i >= (int)ARRAY_SIZE(bpf_testcase_table))
 339                 return TEST_FAIL;
 340
 341         if (geteuid() != 0) {
 342                 pr_debug("Only root can run BPF test\n");
 343                 return TEST_SKIP;
 344         }
 345
 346         if (check_env())
 347                 return TEST_SKIP;
 348
 349         err = __test__bpf(i);
 350         return err;
 351 }
 352
 353 #else
 354 int test__bpf_subtest_get_nr(void)
 355 {
 356         return 0;
 357 }
 358
 359 const char *test__bpf_subtest_get_desc(int i __maybe_unused)
 360 {
 361         return NULL;
 362 }
 363
 364 int test__bpf(struct test *test __maybe_unused, int i __maybe_unused)
 365 {
 366         pr_debug("Skip BPF test because BPF support is not compiled\n");
 367         return TEST_SKIP;
 368 }
 369 #endif