Commit 3b037911 authored by Maciej Fijalkowski's avatar Maciej Fijalkowski Committed by Alexei Starovoitov
Browse files

selftests/bpf: Add tailcall_bpf2bpf tests 



Add four tests to tailcalls selftest explicitly named
"tailcall_bpf2bpf_X" as their purpose is to validate that combination
of tailcalls with bpf2bpf calls are working properly.
These tests also validate LD_ABS from subprograms.

Signed-off-by: default avatarMaciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 09b28d76

tools/testing/selftests/bpf/prog_tests/tailcalls.c

+332 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

#include <test_progs.h>

#include <network_helpers.h>



/* test_tailcall_1 checks basic functionality by patching multiple locations

 * in a single program for a single tail call slot with nop->jmp, jmp->nop
@@ -472,6 +473,329 @@ static void test_tailcall_5(void) 
	bpf_object__close(obj);

}



/* test_tailcall_bpf2bpf_1 purpose is to make sure that tailcalls are working

 * correctly in correlation with BPF subprograms

 */

static void test_tailcall_bpf2bpf_1(void)

{

	int err, map_fd, prog_fd, main_fd, i;

	struct bpf_map *prog_array;

	struct bpf_program *prog;

	struct bpf_object *obj;

	__u32 retval, duration;

	char prog_name[32];



	err = bpf_prog_load("tailcall_bpf2bpf1.o", BPF_PROG_TYPE_SCHED_CLS,

			    &obj, &prog_fd);

	if (CHECK_FAIL(err))

		return;



	prog = bpf_object__find_program_by_title(obj, "classifier");

	if (CHECK_FAIL(!prog))

		goto out;



	main_fd = bpf_program__fd(prog);

	if (CHECK_FAIL(main_fd < 0))

		goto out;



	prog_array = bpf_object__find_map_by_name(obj, "jmp_table");

	if (CHECK_FAIL(!prog_array))

		goto out;



	map_fd = bpf_map__fd(prog_array);

	if (CHECK_FAIL(map_fd < 0))

		goto out;



	/* nop -> jmp */

	for (i = 0; i < bpf_map__def(prog_array)->max_entries; i++) {

		snprintf(prog_name, sizeof(prog_name), "classifier/%i", i);



		prog = bpf_object__find_program_by_title(obj, prog_name);

		if (CHECK_FAIL(!prog))

			goto out;



		prog_fd = bpf_program__fd(prog);

		if (CHECK_FAIL(prog_fd < 0))

			goto out;



		err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);

		if (CHECK_FAIL(err))

			goto out;

	}



	err = bpf_prog_test_run(main_fd, 1, &pkt_v4, sizeof(pkt_v4), 0,

				0, &retval, &duration);

	CHECK(err || retval != 1, "tailcall",

	      "err %d errno %d retval %d\n", err, errno, retval);



	/* jmp -> nop, call subprog that will do tailcall */

	i = 1;

	err = bpf_map_delete_elem(map_fd, &i);

	if (CHECK_FAIL(err))

		goto out;



	err = bpf_prog_test_run(main_fd, 1, &pkt_v4, sizeof(pkt_v4), 0,

				0, &retval, &duration);

	CHECK(err || retval != 0, "tailcall", "err %d errno %d retval %d\n",

	      err, errno, retval);



	/* make sure that subprog can access ctx and entry prog that

	 * called this subprog can properly return

	 */

	i = 0;

	err = bpf_map_delete_elem(map_fd, &i);

	if (CHECK_FAIL(err))

		goto out;



	err = bpf_prog_test_run(main_fd, 1, &pkt_v4, sizeof(pkt_v4), 0,

				0, &retval, &duration);

	CHECK(err || retval != sizeof(pkt_v4) * 2,

	      "tailcall", "err %d errno %d retval %d\n",

	      err, errno, retval);

out:

	bpf_object__close(obj);

}



/* test_tailcall_bpf2bpf_2 checks that the count value of the tail call limit

 * enforcement matches with expectations when tailcall is preceded with

 * bpf2bpf call.

 */

static void test_tailcall_bpf2bpf_2(void)

{

	int err, map_fd, prog_fd, main_fd, data_fd, i, val;

	struct bpf_map *prog_array, *data_map;

	struct bpf_program *prog;

	struct bpf_object *obj;

	__u32 retval, duration;

	char buff[128] = {};



	err = bpf_prog_load("tailcall_bpf2bpf2.o", BPF_PROG_TYPE_SCHED_CLS,

			    &obj, &prog_fd);

	if (CHECK_FAIL(err))

		return;



	prog = bpf_object__find_program_by_title(obj, "classifier");

	if (CHECK_FAIL(!prog))

		goto out;



	main_fd = bpf_program__fd(prog);

	if (CHECK_FAIL(main_fd < 0))

		goto out;



	prog_array = bpf_object__find_map_by_name(obj, "jmp_table");

	if (CHECK_FAIL(!prog_array))

		goto out;



	map_fd = bpf_map__fd(prog_array);

	if (CHECK_FAIL(map_fd < 0))

		goto out;



	prog = bpf_object__find_program_by_title(obj, "classifier/0");

	if (CHECK_FAIL(!prog))

		goto out;



	prog_fd = bpf_program__fd(prog);

	if (CHECK_FAIL(prog_fd < 0))

		goto out;



	i = 0;

	err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);

	if (CHECK_FAIL(err))

		goto out;



	err = bpf_prog_test_run(main_fd, 1, buff, sizeof(buff), 0,

				&duration, &retval, NULL);

	CHECK(err || retval != 1, "tailcall", "err %d errno %d retval %d\n",

	      err, errno, retval);



	data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");

	if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))

		return;



	data_fd = bpf_map__fd(data_map);

	if (CHECK_FAIL(map_fd < 0))

		return;



	i = 0;

	err = bpf_map_lookup_elem(data_fd, &i, &val);

	CHECK(err || val != 33, "tailcall count", "err %d errno %d count %d\n",

	      err, errno, val);



	i = 0;

	err = bpf_map_delete_elem(map_fd, &i);

	if (CHECK_FAIL(err))

		goto out;



	err = bpf_prog_test_run(main_fd, 1, buff, sizeof(buff), 0,

				&duration, &retval, NULL);

	CHECK(err || retval != 0, "tailcall", "err %d errno %d retval %d\n",

	      err, errno, retval);

out:

	bpf_object__close(obj);

}



/* test_tailcall_bpf2bpf_3 checks that non-trivial amount of stack (up to

 * 256 bytes) can be used within bpf subprograms that have the tailcalls

 * in them

 */

static void test_tailcall_bpf2bpf_3(void)

{

	int err, map_fd, prog_fd, main_fd, i;

	struct bpf_map *prog_array;

	struct bpf_program *prog;

	struct bpf_object *obj;

	__u32 retval, duration;

	char prog_name[32];



	err = bpf_prog_load("tailcall_bpf2bpf3.o", BPF_PROG_TYPE_SCHED_CLS,

			    &obj, &prog_fd);

	if (CHECK_FAIL(err))

		return;



	prog = bpf_object__find_program_by_title(obj, "classifier");

	if (CHECK_FAIL(!prog))

		goto out;



	main_fd = bpf_program__fd(prog);

	if (CHECK_FAIL(main_fd < 0))

		goto out;



	prog_array = bpf_object__find_map_by_name(obj, "jmp_table");

	if (CHECK_FAIL(!prog_array))

		goto out;



	map_fd = bpf_map__fd(prog_array);

	if (CHECK_FAIL(map_fd < 0))

		goto out;



	for (i = 0; i < bpf_map__def(prog_array)->max_entries; i++) {

		snprintf(prog_name, sizeof(prog_name), "classifier/%i", i);



		prog = bpf_object__find_program_by_title(obj, prog_name);

		if (CHECK_FAIL(!prog))

			goto out;



		prog_fd = bpf_program__fd(prog);

		if (CHECK_FAIL(prog_fd < 0))

			goto out;



		err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);

		if (CHECK_FAIL(err))

			goto out;

	}



	err = bpf_prog_test_run(main_fd, 1, &pkt_v4, sizeof(pkt_v4), 0,

				&duration, &retval, NULL);

	CHECK(err || retval != sizeof(pkt_v4) * 3,

	      "tailcall", "err %d errno %d retval %d\n",

	      err, errno, retval);



	i = 1;

	err = bpf_map_delete_elem(map_fd, &i);

	if (CHECK_FAIL(err))

		goto out;



	err = bpf_prog_test_run(main_fd, 1, &pkt_v4, sizeof(pkt_v4), 0,

				&duration, &retval, NULL);

	CHECK(err || retval != sizeof(pkt_v4),

	      "tailcall", "err %d errno %d retval %d\n",

	      err, errno, retval);



	i = 0;

	err = bpf_map_delete_elem(map_fd, &i);

	if (CHECK_FAIL(err))

		goto out;



	err = bpf_prog_test_run(main_fd, 1, &pkt_v4, sizeof(pkt_v4), 0,

				&duration, &retval, NULL);

	CHECK(err || retval != sizeof(pkt_v4) * 2,

	      "tailcall", "err %d errno %d retval %d\n",

	      err, errno, retval);

out:

	bpf_object__close(obj);

}



/* test_tailcall_bpf2bpf_4 checks that tailcall counter is correctly preserved

 * across tailcalls combined with bpf2bpf calls. for making sure that tailcall

 * counter behaves correctly, bpf program will go through following flow:

 *

 * entry -> entry_subprog -> tailcall0 -> bpf_func0 -> subprog0 ->

 * -> tailcall1 -> bpf_func1 -> subprog1 -> tailcall2 -> bpf_func2 ->

 * subprog2 [here bump global counter] --------^

 *

 * We go through first two tailcalls and start counting from the subprog2 where

 * the loop begins. At the end of the test make sure that the global counter is

 * equal to 31, because tailcall counter includes the first two tailcalls

 * whereas global counter is incremented only on loop presented on flow above.

 */

static void test_tailcall_bpf2bpf_4(void)

{

	int err, map_fd, prog_fd, main_fd, data_fd, i, val;

	struct bpf_map *prog_array, *data_map;

	struct bpf_program *prog;

	struct bpf_object *obj;

	__u32 retval, duration;

	char prog_name[32];



	err = bpf_prog_load("tailcall_bpf2bpf4.o", BPF_PROG_TYPE_SCHED_CLS,

			    &obj, &prog_fd);

	if (CHECK_FAIL(err))

		return;



	prog = bpf_object__find_program_by_title(obj, "classifier");

	if (CHECK_FAIL(!prog))

		goto out;



	main_fd = bpf_program__fd(prog);

	if (CHECK_FAIL(main_fd < 0))

		goto out;



	prog_array = bpf_object__find_map_by_name(obj, "jmp_table");

	if (CHECK_FAIL(!prog_array))

		goto out;



	map_fd = bpf_map__fd(prog_array);

	if (CHECK_FAIL(map_fd < 0))

		goto out;



	for (i = 0; i < bpf_map__def(prog_array)->max_entries; i++) {

		snprintf(prog_name, sizeof(prog_name), "classifier/%i", i);



		prog = bpf_object__find_program_by_title(obj, prog_name);

		if (CHECK_FAIL(!prog))

			goto out;



		prog_fd = bpf_program__fd(prog);

		if (CHECK_FAIL(prog_fd < 0))

			goto out;



		err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);

		if (CHECK_FAIL(err))

			goto out;

	}



	err = bpf_prog_test_run(main_fd, 1, &pkt_v4, sizeof(pkt_v4), 0,

				&duration, &retval, NULL);

	CHECK(err || retval != sizeof(pkt_v4) * 3, "tailcall", "err %d errno %d retval %d\n",

	      err, errno, retval);



	data_map = bpf_object__find_map_by_name(obj, "tailcall.bss");

	if (CHECK_FAIL(!data_map || !bpf_map__is_internal(data_map)))

		return;



	data_fd = bpf_map__fd(data_map);

	if (CHECK_FAIL(map_fd < 0))

		return;



	i = 0;

	err = bpf_map_lookup_elem(data_fd, &i, &val);

	CHECK(err || val != 31, "tailcall count", "err %d errno %d count %d\n",

	      err, errno, val);



out:

	bpf_object__close(obj);

}



void test_tailcalls(void)

{

	if (test__start_subtest("tailcall_1"))
@@ -484,4 +808,12 @@ void test_tailcalls(void) 
		test_tailcall_4();

	if (test__start_subtest("tailcall_5"))

		test_tailcall_5();

	if (test__start_subtest("tailcall_bpf2bpf_1"))

		test_tailcall_bpf2bpf_1();

	if (test__start_subtest("tailcall_bpf2bpf_2"))

		test_tailcall_bpf2bpf_2();

	if (test__start_subtest("tailcall_bpf2bpf_3"))

		test_tailcall_bpf2bpf_3();

	if (test__start_subtest("tailcall_bpf2bpf_4"))

		test_tailcall_bpf2bpf_4();

}

tools/testing/selftests/bpf/progs/tailcall_bpf2bpf1.c

0 → 100644
+38 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

#include <linux/bpf.h>

#include <bpf/bpf_helpers.h>



struct {

	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);

	__uint(max_entries, 2);

	__uint(key_size, sizeof(__u32));

	__uint(value_size, sizeof(__u32));

} jmp_table SEC(".maps");



#define TAIL_FUNC(x) 				\

	SEC("classifier/" #x)			\

	int bpf_func_##x(struct __sk_buff *skb)	\

	{					\

		return x;			\

	}

TAIL_FUNC(0)

TAIL_FUNC(1)



static __noinline

int subprog_tail(struct __sk_buff *skb)

{

	bpf_tail_call(skb, &jmp_table, 0);



	return skb->len * 2;

}



SEC("classifier")

int entry(struct __sk_buff *skb)

{

	bpf_tail_call(skb, &jmp_table, 1);



	return subprog_tail(skb);

}



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

int _version SEC("version") = 1;

tools/testing/selftests/bpf/progs/tailcall_bpf2bpf2.c

0 → 100644
+41 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

#include <linux/bpf.h>

#include <bpf/bpf_helpers.h>

#include "bpf_legacy.h"



struct {

	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);

	__uint(max_entries, 1);

	__uint(key_size, sizeof(__u32));

	__uint(value_size, sizeof(__u32));

} jmp_table SEC(".maps");



static __noinline

int subprog_tail(struct __sk_buff *skb)

{

	if (load_byte(skb, 0))

		bpf_tail_call(skb, &jmp_table, 1);

	else

		bpf_tail_call(skb, &jmp_table, 0);

	return 1;

}



static volatile int count;



SEC("classifier/0")

int bpf_func_0(struct __sk_buff *skb)

{

	count++;

	return subprog_tail(skb);

}



SEC("classifier")

int entry(struct __sk_buff *skb)

{

	bpf_tail_call(skb, &jmp_table, 0);



	return 0;

}



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

int _version SEC("version") = 1;

tools/testing/selftests/bpf/progs/tailcall_bpf2bpf3.c

0 → 100644
+61 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

#include <linux/bpf.h>

#include <bpf/bpf_helpers.h>

#include "bpf_legacy.h"



struct {

	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);

	__uint(max_entries, 2);

	__uint(key_size, sizeof(__u32));

	__uint(value_size, sizeof(__u32));

} jmp_table SEC(".maps");



__noinline

int subprog_tail2(struct __sk_buff *skb)

{

	volatile char arr[64] = {};



	if (load_word(skb, 0) || load_half(skb, 0))

		bpf_tail_call(skb, &jmp_table, 10);

	else

		bpf_tail_call(skb, &jmp_table, 1);



	return skb->len;

}



static __noinline

int subprog_tail(struct __sk_buff *skb)

{

	volatile char arr[64] = {};



	bpf_tail_call(skb, &jmp_table, 0);



	return skb->len * 2;

}



SEC("classifier/0")

int bpf_func_0(struct __sk_buff *skb)

{

	volatile char arr[128] = {};



	return subprog_tail2(skb);

}



SEC("classifier/1")

int bpf_func_1(struct __sk_buff *skb)

{

	volatile char arr[128] = {};



	return skb->len * 3;

}



SEC("classifier")

int entry(struct __sk_buff *skb)

{

	volatile char arr[128] = {};



	return subprog_tail(skb);

}



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

int _version SEC("version") = 1;

tools/testing/selftests/bpf/progs/tailcall_bpf2bpf4.c

0 → 100644
+61 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

#include <linux/bpf.h>

#include <bpf/bpf_helpers.h>



struct {

	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);

	__uint(max_entries, 3);

	__uint(key_size, sizeof(__u32));

	__uint(value_size, sizeof(__u32));

} jmp_table SEC(".maps");



static volatile int count;



__noinline

int subprog_tail_2(struct __sk_buff *skb)

{

	bpf_tail_call(skb, &jmp_table, 2);

	return skb->len * 3;

}



__noinline

int subprog_tail_1(struct __sk_buff *skb)

{

	bpf_tail_call(skb, &jmp_table, 1);

	return skb->len * 2;

}



__noinline

int subprog_tail(struct __sk_buff *skb)

{

	bpf_tail_call(skb, &jmp_table, 0);

	return skb->len;

}



SEC("classifier/1")

int bpf_func_1(struct __sk_buff *skb)

{

	return subprog_tail_2(skb);

}



SEC("classifier/2")

int bpf_func_2(struct __sk_buff *skb)

{

	count++;

	return subprog_tail_2(skb);

}



SEC("classifier/0")

int bpf_func_0(struct __sk_buff *skb)

{

	return subprog_tail_1(skb);

}



SEC("classifier")

int entry(struct __sk_buff *skb)

{

	return subprog_tail(skb);

}



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

int _version SEC("version") = 1;