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