LXR linux/tools/testing/selftests/bpf/prog

   1// SPDX-License-Identifier: GPL-2.0
   2#include <test_progs.h>
   3#include <sys/mman.h>
   4
   5struct map_data {
   6        __u64 val[512 * 4];
   7};
   8
   9struct bss_data {
  10        __u64 in_val;
  11        __u64 out_val;
  12};
  13
  14static size_t roundup_page(size_t sz)
  15{
  16        long page_size = sysconf(_SC_PAGE_SIZE);
  17        return (sz + page_size - 1) / page_size * page_size;
  18}
  19
  20void test_mmap(void)
  21{
  22        const char *file = "test_mmap.o";
  23        const char *probe_name = "raw_tracepoint/sys_enter";
  24        const char *tp_name = "sys_enter";
  25        const size_t bss_sz = roundup_page(sizeof(struct bss_data));
  26        const size_t map_sz = roundup_page(sizeof(struct map_data));
  27        const int zero = 0, one = 1, two = 2, far = 1500;
  28        const long page_size = sysconf(_SC_PAGE_SIZE);
  29        int err, duration = 0, i, data_map_fd;
  30        struct bpf_program *prog;
  31        struct bpf_object *obj;
  32        struct bpf_link *link = NULL;
  33        struct bpf_map *data_map, *bss_map;
  34        void *bss_mmaped = NULL, *map_mmaped = NULL, *tmp1, *tmp2;
  35        volatile struct bss_data *bss_data;
  36        volatile struct map_data *map_data;
  37        __u64 val = 0;
  38
  39        obj = bpf_object__open_file("test_mmap.o", NULL);
  40        if (CHECK(IS_ERR(obj), "obj_open", "failed to open '%s': %ld\n",
  41                  file, PTR_ERR(obj)))
  42                return;
  43        prog = bpf_object__find_program_by_title(obj, probe_name);
  44        if (CHECK(!prog, "find_probe", "prog '%s' not found\n", probe_name))
  45                goto cleanup;
  46        err = bpf_object__load(obj);
  47        if (CHECK(err, "obj_load", "failed to load prog '%s': %d\n",
  48                  probe_name, err))
  49                goto cleanup;
  50
  51        bss_map = bpf_object__find_map_by_name(obj, "test_mma.bss");
  52        if (CHECK(!bss_map, "find_bss_map", ".bss map not found\n"))
  53                goto cleanup;
  54        data_map = bpf_object__find_map_by_name(obj, "data_map");
  55        if (CHECK(!data_map, "find_data_map", "data_map map not found\n"))
  56                goto cleanup;
  57        data_map_fd = bpf_map__fd(data_map);
  58
  59        bss_mmaped = mmap(NULL, bss_sz, PROT_READ | PROT_WRITE, MAP_SHARED,
  60                          bpf_map__fd(bss_map), 0);
  61        if (CHECK(bss_mmaped == MAP_FAILED, "bss_mmap",
  62                  ".bss mmap failed: %d\n", errno)) {
  63                bss_mmaped = NULL;
  64                goto cleanup;
  65        }
  66        /* map as R/W first */
  67        map_mmaped = mmap(NULL, map_sz, PROT_READ | PROT_WRITE, MAP_SHARED,
  68                          data_map_fd, 0);
  69        if (CHECK(map_mmaped == MAP_FAILED, "data_mmap",
  70                  "data_map mmap failed: %d\n", errno)) {
  71                map_mmaped = NULL;
  72                goto cleanup;
  73        }
  74
  75        bss_data = bss_mmaped;
  76        map_data = map_mmaped;
  77
  78        CHECK_FAIL(bss_data->in_val);
  79        CHECK_FAIL(bss_data->out_val);
  80        CHECK_FAIL(map_data->val[0]);
  81        CHECK_FAIL(map_data->val[1]);
  82        CHECK_FAIL(map_data->val[2]);
  83        CHECK_FAIL(map_data->val[far]);
  84
  85        link = bpf_program__attach_raw_tracepoint(prog, tp_name);
  86        if (CHECK(IS_ERR(link), "attach_raw_tp", "err %ld\n", PTR_ERR(link)))
  87                goto cleanup;
  88
  89        bss_data->in_val = 123;
  90        val = 111;
  91        CHECK_FAIL(bpf_map_update_elem(data_map_fd, &zero, &val, 0));
  92
  93        usleep(1);
  94
  95        CHECK_FAIL(bss_data->in_val != 123);
  96        CHECK_FAIL(bss_data->out_val != 123);
  97        CHECK_FAIL(map_data->val[0] != 111);
  98        CHECK_FAIL(map_data->val[1] != 222);
  99        CHECK_FAIL(map_data->val[2] != 123);
 100        CHECK_FAIL(map_data->val[far] != 3 * 123);
 101
 102        CHECK_FAIL(bpf_map_lookup_elem(data_map_fd, &zero, &val));
 103        CHECK_FAIL(val != 111);
 104        CHECK_FAIL(bpf_map_lookup_elem(data_map_fd, &one, &val));
 105        CHECK_FAIL(val != 222);
 106        CHECK_FAIL(bpf_map_lookup_elem(data_map_fd, &two, &val));
 107        CHECK_FAIL(val != 123);
 108        CHECK_FAIL(bpf_map_lookup_elem(data_map_fd, &far, &val));
 109        CHECK_FAIL(val != 3 * 123);
 110
 111        /* data_map freeze should fail due to R/W mmap() */
 112        err = bpf_map_freeze(data_map_fd);
 113        if (CHECK(!err || errno != EBUSY, "no_freeze",
 114                  "data_map freeze succeeded: err=%d, errno=%d\n", err, errno))
 115                goto cleanup;
 116
 117        /* unmap R/W mapping */
 118        err = munmap(map_mmaped, map_sz);
 119        map_mmaped = NULL;
 120        if (CHECK(err, "data_map_munmap", "data_map munmap failed: %d\n", errno))
 121                goto cleanup;
 122
 123        /* re-map as R/O now */
 124        map_mmaped = mmap(NULL, map_sz, PROT_READ, MAP_SHARED, data_map_fd, 0);
 125        if (CHECK(map_mmaped == MAP_FAILED, "data_mmap",
 126                  "data_map R/O mmap failed: %d\n", errno)) {
 127                map_mmaped = NULL;
 128                goto cleanup;
 129        }
 130        map_data = map_mmaped;
 131
 132        /* map/unmap in a loop to test ref counting */
 133        for (i = 0; i < 10; i++) {
 134                int flags = i % 2 ? PROT_READ : PROT_WRITE;
 135                void *p;
 136
 137                p = mmap(NULL, map_sz, flags, MAP_SHARED, data_map_fd, 0);
 138                if (CHECK_FAIL(p == MAP_FAILED))
 139                        goto cleanup;
 140                err = munmap(p, map_sz);
 141                if (CHECK_FAIL(err))
 142                        goto cleanup;
 143        }
 144
 145        /* data_map freeze should now succeed due to no R/W mapping */
 146        err = bpf_map_freeze(data_map_fd);
 147        if (CHECK(err, "freeze", "data_map freeze failed: err=%d, errno=%d\n",
 148                  err, errno))
 149                goto cleanup;
 150
 151        /* mapping as R/W now should fail */
 152        tmp1 = mmap(NULL, map_sz, PROT_READ | PROT_WRITE, MAP_SHARED,
 153                    data_map_fd, 0);
 154        if (CHECK(tmp1 != MAP_FAILED, "data_mmap", "mmap succeeded\n")) {
 155                munmap(tmp1, map_sz);
 156                goto cleanup;
 157        }
 158
 159        bss_data->in_val = 321;
 160        usleep(1);
 161        CHECK_FAIL(bss_data->in_val != 321);
 162        CHECK_FAIL(bss_data->out_val != 321);
 163        CHECK_FAIL(map_data->val[0] != 111);
 164        CHECK_FAIL(map_data->val[1] != 222);
 165        CHECK_FAIL(map_data->val[2] != 321);
 166        CHECK_FAIL(map_data->val[far] != 3 * 321);
 167
 168        /* check some more advanced mmap() manipulations */
 169
 170        /* map all but last page: pages 1-3 mapped */
 171        tmp1 = mmap(NULL, 3 * page_size, PROT_READ, MAP_SHARED,
 172                          data_map_fd, 0);
 173        if (CHECK(tmp1 == MAP_FAILED, "adv_mmap1", "errno %d\n", errno))
 174                goto cleanup;
 175
 176        /* unmap second page: pages 1, 3 mapped */
 177        err = munmap(tmp1 + page_size, page_size);
 178        if (CHECK(err, "adv_mmap2", "errno %d\n", errno)) {
 179                munmap(tmp1, map_sz);
 180                goto cleanup;
 181        }
 182
 183        /* map page 2 back */
 184        tmp2 = mmap(tmp1 + page_size, page_size, PROT_READ,
 185                    MAP_SHARED | MAP_FIXED, data_map_fd, 0);
 186        if (CHECK(tmp2 == MAP_FAILED, "adv_mmap3", "errno %d\n", errno)) {
 187                munmap(tmp1, page_size);
 188                munmap(tmp1 + 2*page_size, page_size);
 189                goto cleanup;
 190        }
 191        CHECK(tmp1 + page_size != tmp2, "adv_mmap4",
 192              "tmp1: %p, tmp2: %p\n", tmp1, tmp2);
 193
 194        /* re-map all 4 pages */
 195        tmp2 = mmap(tmp1, 4 * page_size, PROT_READ, MAP_SHARED | MAP_FIXED,
 196                    data_map_fd, 0);
 197        if (CHECK(tmp2 == MAP_FAILED, "adv_mmap5", "errno %d\n", errno)) {
 198                munmap(tmp1, 3 * page_size); /* unmap page 1 */
 199                goto cleanup;
 200        }
 201        CHECK(tmp1 != tmp2, "adv_mmap6", "tmp1: %p, tmp2: %p\n", tmp1, tmp2);
 202
 203        map_data = tmp2;
 204        CHECK_FAIL(bss_data->in_val != 321);
 205        CHECK_FAIL(bss_data->out_val != 321);
 206        CHECK_FAIL(map_data->val[0] != 111);
 207        CHECK_FAIL(map_data->val[1] != 222);
 208        CHECK_FAIL(map_data->val[2] != 321);
 209        CHECK_FAIL(map_data->val[far] != 3 * 321);
 210
 211        munmap(tmp2, 4 * page_size);
 212cleanup:
 213        if (bss_mmaped)
 214                CHECK_FAIL(munmap(bss_mmaped, bss_sz));
 215        if (map_mmaped)
 216                CHECK_FAIL(munmap(map_mmaped, map_sz));
 217        if (!IS_ERR_OR_NULL(link))
 218                bpf_link__destroy(link);
 219        bpf_object__close(obj);
 220}
 221