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