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selftests/bpf: Add BPF_TYPE_MAP_ARRAY mmap() tests
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Add selftests validating mmap()-ing BPF array maps: both single-element and
multi-element ones. Check that plain bpf_map_update_elem() and
bpf_map_lookup_elem() work correctly with memory-mapped array. Also convert
CO-RE relocation tests to use memory-mapped views of global data.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20191117172806.2195367-6-andriin@fb.com
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Andrii Nakryiko authored and Daniel Borkmann committed Nov 18, 2019
1 parent 7fe74b4 commit 5051b38
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45 changes: 27 additions & 18 deletions tools/testing/selftests/bpf/prog_tests/core_reloc.c
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
#include <test_progs.h>
#include "progs/core_reloc_types.h"
#include <sys/mman.h>

#define STRUCT_TO_CHAR_PTR(struct_name) (const char *)&(struct struct_name)

Expand Down Expand Up @@ -453,8 +454,15 @@ struct data {
char out[256];
};

static size_t roundup_page(size_t sz)
{
long page_size = sysconf(_SC_PAGE_SIZE);
return (sz + page_size - 1) / page_size * page_size;
}

void test_core_reloc(void)
{
const size_t mmap_sz = roundup_page(sizeof(struct data));
struct bpf_object_load_attr load_attr = {};
struct core_reloc_test_case *test_case;
const char *tp_name, *probe_name;
Expand All @@ -463,8 +471,8 @@ void test_core_reloc(void)
struct bpf_map *data_map;
struct bpf_program *prog;
struct bpf_object *obj;
const int zero = 0;
struct data data;
struct data *data;
void *mmap_data = NULL;

for (i = 0; i < ARRAY_SIZE(test_cases); i++) {
test_case = &test_cases[i];
Expand All @@ -476,8 +484,7 @@ void test_core_reloc(void)
);

obj = bpf_object__open_file(test_case->bpf_obj_file, &opts);
if (CHECK(IS_ERR_OR_NULL(obj), "obj_open",
"failed to open '%s': %ld\n",
if (CHECK(IS_ERR(obj), "obj_open", "failed to open '%s': %ld\n",
test_case->bpf_obj_file, PTR_ERR(obj)))
continue;

Expand Down Expand Up @@ -519,24 +526,22 @@ void test_core_reloc(void)
if (CHECK(!data_map, "find_data_map", "data map not found\n"))
goto cleanup;

memset(&data, 0, sizeof(data));
memcpy(data.in, test_case->input, test_case->input_len);

err = bpf_map_update_elem(bpf_map__fd(data_map),
&zero, &data, 0);
if (CHECK(err, "update_data_map",
"failed to update .data map: %d\n", err))
mmap_data = mmap(NULL, mmap_sz, PROT_READ | PROT_WRITE,
MAP_SHARED, bpf_map__fd(data_map), 0);
if (CHECK(mmap_data == MAP_FAILED, "mmap",
".bss mmap failed: %d", errno)) {
mmap_data = NULL;
goto cleanup;
}
data = mmap_data;

memset(mmap_data, 0, sizeof(*data));
memcpy(data->in, test_case->input, test_case->input_len);

/* trigger test run */
usleep(1);

err = bpf_map_lookup_elem(bpf_map__fd(data_map), &zero, &data);
if (CHECK(err, "get_result",
"failed to get output data: %d\n", err))
goto cleanup;

equal = memcmp(data.out, test_case->output,
equal = memcmp(data->out, test_case->output,
test_case->output_len) == 0;
if (CHECK(!equal, "check_result",
"input/output data don't match\n")) {
Expand All @@ -548,12 +553,16 @@ void test_core_reloc(void)
}
for (j = 0; j < test_case->output_len; j++) {
printf("output byte #%d: EXP 0x%02hhx GOT 0x%02hhx\n",
j, test_case->output[j], data.out[j]);
j, test_case->output[j], data->out[j]);
}
goto cleanup;
}

cleanup:
if (mmap_data) {
CHECK_FAIL(munmap(mmap_data, mmap_sz));
mmap_data = NULL;
}
if (!IS_ERR_OR_NULL(link)) {
bpf_link__destroy(link);
link = NULL;
Expand Down
220 changes: 220 additions & 0 deletions tools/testing/selftests/bpf/prog_tests/mmap.c
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Original file line number Diff line number Diff line change
@@ -0,0 +1,220 @@
// SPDX-License-Identifier: GPL-2.0
#include <test_progs.h>
#include <sys/mman.h>

struct map_data {
__u64 val[512 * 4];
};

struct bss_data {
__u64 in_val;
__u64 out_val;
};

static size_t roundup_page(size_t sz)
{
long page_size = sysconf(_SC_PAGE_SIZE);
return (sz + page_size - 1) / page_size * page_size;
}

void test_mmap(void)
{
const char *file = "test_mmap.o";
const char *probe_name = "raw_tracepoint/sys_enter";
const char *tp_name = "sys_enter";
const size_t bss_sz = roundup_page(sizeof(struct bss_data));
const size_t map_sz = roundup_page(sizeof(struct map_data));
const int zero = 0, one = 1, two = 2, far = 1500;
const long page_size = sysconf(_SC_PAGE_SIZE);
int err, duration = 0, i, data_map_fd;
struct bpf_program *prog;
struct bpf_object *obj;
struct bpf_link *link = NULL;
struct bpf_map *data_map, *bss_map;
void *bss_mmaped = NULL, *map_mmaped = NULL, *tmp1, *tmp2;
volatile struct bss_data *bss_data;
volatile struct map_data *map_data;
__u64 val = 0;

obj = bpf_object__open_file("test_mmap.o", NULL);
if (CHECK(IS_ERR(obj), "obj_open", "failed to open '%s': %ld\n",
file, PTR_ERR(obj)))
return;
prog = bpf_object__find_program_by_title(obj, probe_name);
if (CHECK(!prog, "find_probe", "prog '%s' not found\n", probe_name))
goto cleanup;
err = bpf_object__load(obj);
if (CHECK(err, "obj_load", "failed to load prog '%s': %d\n",
probe_name, err))
goto cleanup;

bss_map = bpf_object__find_map_by_name(obj, "test_mma.bss");
if (CHECK(!bss_map, "find_bss_map", ".bss map not found\n"))
goto cleanup;
data_map = bpf_object__find_map_by_name(obj, "data_map");
if (CHECK(!data_map, "find_data_map", "data_map map not found\n"))
goto cleanup;
data_map_fd = bpf_map__fd(data_map);

bss_mmaped = mmap(NULL, bss_sz, PROT_READ | PROT_WRITE, MAP_SHARED,
bpf_map__fd(bss_map), 0);
if (CHECK(bss_mmaped == MAP_FAILED, "bss_mmap",
".bss mmap failed: %d\n", errno)) {
bss_mmaped = NULL;
goto cleanup;
}
/* map as R/W first */
map_mmaped = mmap(NULL, map_sz, PROT_READ | PROT_WRITE, MAP_SHARED,
data_map_fd, 0);
if (CHECK(map_mmaped == MAP_FAILED, "data_mmap",
"data_map mmap failed: %d\n", errno)) {
map_mmaped = NULL;
goto cleanup;
}

bss_data = bss_mmaped;
map_data = map_mmaped;

CHECK_FAIL(bss_data->in_val);
CHECK_FAIL(bss_data->out_val);
CHECK_FAIL(map_data->val[0]);
CHECK_FAIL(map_data->val[1]);
CHECK_FAIL(map_data->val[2]);
CHECK_FAIL(map_data->val[far]);

link = bpf_program__attach_raw_tracepoint(prog, tp_name);
if (CHECK(IS_ERR(link), "attach_raw_tp", "err %ld\n", PTR_ERR(link)))
goto cleanup;

bss_data->in_val = 123;
val = 111;
CHECK_FAIL(bpf_map_update_elem(data_map_fd, &zero, &val, 0));

usleep(1);

CHECK_FAIL(bss_data->in_val != 123);
CHECK_FAIL(bss_data->out_val != 123);
CHECK_FAIL(map_data->val[0] != 111);
CHECK_FAIL(map_data->val[1] != 222);
CHECK_FAIL(map_data->val[2] != 123);
CHECK_FAIL(map_data->val[far] != 3 * 123);

CHECK_FAIL(bpf_map_lookup_elem(data_map_fd, &zero, &val));
CHECK_FAIL(val != 111);
CHECK_FAIL(bpf_map_lookup_elem(data_map_fd, &one, &val));
CHECK_FAIL(val != 222);
CHECK_FAIL(bpf_map_lookup_elem(data_map_fd, &two, &val));
CHECK_FAIL(val != 123);
CHECK_FAIL(bpf_map_lookup_elem(data_map_fd, &far, &val));
CHECK_FAIL(val != 3 * 123);

/* data_map freeze should fail due to R/W mmap() */
err = bpf_map_freeze(data_map_fd);
if (CHECK(!err || errno != EBUSY, "no_freeze",
"data_map freeze succeeded: err=%d, errno=%d\n", err, errno))
goto cleanup;

/* unmap R/W mapping */
err = munmap(map_mmaped, map_sz);
map_mmaped = NULL;
if (CHECK(err, "data_map_munmap", "data_map munmap failed: %d\n", errno))
goto cleanup;

/* re-map as R/O now */
map_mmaped = mmap(NULL, map_sz, PROT_READ, MAP_SHARED, data_map_fd, 0);
if (CHECK(map_mmaped == MAP_FAILED, "data_mmap",
"data_map R/O mmap failed: %d\n", errno)) {
map_mmaped = NULL;
goto cleanup;
}
map_data = map_mmaped;

/* map/unmap in a loop to test ref counting */
for (i = 0; i < 10; i++) {
int flags = i % 2 ? PROT_READ : PROT_WRITE;
void *p;

p = mmap(NULL, map_sz, flags, MAP_SHARED, data_map_fd, 0);
if (CHECK_FAIL(p == MAP_FAILED))
goto cleanup;
err = munmap(p, map_sz);
if (CHECK_FAIL(err))
goto cleanup;
}

/* data_map freeze should now succeed due to no R/W mapping */
err = bpf_map_freeze(data_map_fd);
if (CHECK(err, "freeze", "data_map freeze failed: err=%d, errno=%d\n",
err, errno))
goto cleanup;

/* mapping as R/W now should fail */
tmp1 = mmap(NULL, map_sz, PROT_READ | PROT_WRITE, MAP_SHARED,
data_map_fd, 0);
if (CHECK(tmp1 != MAP_FAILED, "data_mmap", "mmap succeeded\n")) {
munmap(tmp1, map_sz);
goto cleanup;
}

bss_data->in_val = 321;
usleep(1);
CHECK_FAIL(bss_data->in_val != 321);
CHECK_FAIL(bss_data->out_val != 321);
CHECK_FAIL(map_data->val[0] != 111);
CHECK_FAIL(map_data->val[1] != 222);
CHECK_FAIL(map_data->val[2] != 321);
CHECK_FAIL(map_data->val[far] != 3 * 321);

/* check some more advanced mmap() manipulations */

/* map all but last page: pages 1-3 mapped */
tmp1 = mmap(NULL, 3 * page_size, PROT_READ, MAP_SHARED,
data_map_fd, 0);
if (CHECK(tmp1 == MAP_FAILED, "adv_mmap1", "errno %d\n", errno))
goto cleanup;

/* unmap second page: pages 1, 3 mapped */
err = munmap(tmp1 + page_size, page_size);
if (CHECK(err, "adv_mmap2", "errno %d\n", errno)) {
munmap(tmp1, map_sz);
goto cleanup;
}

/* map page 2 back */
tmp2 = mmap(tmp1 + page_size, page_size, PROT_READ,
MAP_SHARED | MAP_FIXED, data_map_fd, 0);
if (CHECK(tmp2 == MAP_FAILED, "adv_mmap3", "errno %d\n", errno)) {
munmap(tmp1, page_size);
munmap(tmp1 + 2*page_size, page_size);
goto cleanup;
}
CHECK(tmp1 + page_size != tmp2, "adv_mmap4",
"tmp1: %p, tmp2: %p\n", tmp1, tmp2);

/* re-map all 4 pages */
tmp2 = mmap(tmp1, 4 * page_size, PROT_READ, MAP_SHARED | MAP_FIXED,
data_map_fd, 0);
if (CHECK(tmp2 == MAP_FAILED, "adv_mmap5", "errno %d\n", errno)) {
munmap(tmp1, 3 * page_size); /* unmap page 1 */
goto cleanup;
}
CHECK(tmp1 != tmp2, "adv_mmap6", "tmp1: %p, tmp2: %p\n", tmp1, tmp2);

map_data = tmp2;
CHECK_FAIL(bss_data->in_val != 321);
CHECK_FAIL(bss_data->out_val != 321);
CHECK_FAIL(map_data->val[0] != 111);
CHECK_FAIL(map_data->val[1] != 222);
CHECK_FAIL(map_data->val[2] != 321);
CHECK_FAIL(map_data->val[far] != 3 * 321);

munmap(tmp2, 4 * page_size);
cleanup:
if (bss_mmaped)
CHECK_FAIL(munmap(bss_mmaped, bss_sz));
if (map_mmaped)
CHECK_FAIL(munmap(map_mmaped, map_sz));
if (!IS_ERR_OR_NULL(link))
bpf_link__destroy(link);
bpf_object__close(obj);
}
45 changes: 45 additions & 0 deletions tools/testing/selftests/bpf/progs/test_mmap.c
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,45 @@
// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2019 Facebook

#include <linux/bpf.h>
#include <stdint.h>
#include "bpf_helpers.h"

char _license[] SEC("license") = "GPL";

struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 512 * 4); /* at least 4 pages of data */
__uint(map_flags, BPF_F_MMAPABLE);
__type(key, __u32);
__type(value, __u64);
} data_map SEC(".maps");

static volatile __u64 in_val;
static volatile __u64 out_val;

SEC("raw_tracepoint/sys_enter")
int test_mmap(void *ctx)
{
int zero = 0, one = 1, two = 2, far = 1500;
__u64 val, *p;

out_val = in_val;

/* data_map[2] = in_val; */
bpf_map_update_elem(&data_map, &two, (const void *)&in_val, 0);

/* data_map[1] = data_map[0] * 2; */
p = bpf_map_lookup_elem(&data_map, &zero);
if (p) {
val = (*p) * 2;
bpf_map_update_elem(&data_map, &one, &val, 0);
}

/* data_map[far] = in_val * 3; */
val = in_val * 3;
bpf_map_update_elem(&data_map, &far, &val, 0);

return 0;
}

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