Commit 006004b7 authored by Jiri Olsa's avatar Jiri Olsa Committed by Alexei Starovoitov
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selftests/bpf: Add tests for get_func_[arg|ret|arg_cnt] helpers 



Adding tests for get_func_[arg|ret|arg_cnt] helpers.
Using these helpers in fentry/fexit/fmod_ret programs.

Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211208193245.172141-6-jolsa@kernel.org
parent f92c1e18

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

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// SPDX-License-Identifier: GPL-2.0

#include <test_progs.h>

#include "get_func_args_test.skel.h"



void test_get_func_args_test(void)

{

	struct get_func_args_test *skel = NULL;

	__u32 duration = 0, retval;

	int err, prog_fd;



	skel = get_func_args_test__open_and_load();

	if (!ASSERT_OK_PTR(skel, "get_func_args_test__open_and_load"))

		return;



	err = get_func_args_test__attach(skel);

	if (!ASSERT_OK(err, "get_func_args_test__attach"))

		goto cleanup;



	/* This runs bpf_fentry_test* functions and triggers

	 * fentry/fexit programs.

	 */

	prog_fd = bpf_program__fd(skel->progs.test1);

	err = bpf_prog_test_run(prog_fd, 1, NULL, 0,

				NULL, NULL, &retval, &duration);

	ASSERT_OK(err, "test_run");

	ASSERT_EQ(retval, 0, "test_run");



	/* This runs bpf_modify_return_test function and triggers

	 * fmod_ret_test and fexit_test programs.

	 */

	prog_fd = bpf_program__fd(skel->progs.fmod_ret_test);

	err = bpf_prog_test_run(prog_fd, 1, NULL, 0,

				NULL, NULL, &retval, &duration);

	ASSERT_OK(err, "test_run");

	ASSERT_EQ(retval, 1234, "test_run");



	ASSERT_EQ(skel->bss->test1_result, 1, "test1_result");

	ASSERT_EQ(skel->bss->test2_result, 1, "test2_result");

	ASSERT_EQ(skel->bss->test3_result, 1, "test3_result");

	ASSERT_EQ(skel->bss->test4_result, 1, "test4_result");



cleanup:

	get_func_args_test__destroy(skel);

}

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

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// SPDX-License-Identifier: GPL-2.0

#include <linux/bpf.h>

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>

#include <errno.h>



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



__u64 test1_result = 0;

SEC("fentry/bpf_fentry_test1")

int BPF_PROG(test1)

{

	__u64 cnt = bpf_get_func_arg_cnt(ctx);

	__u64 a = 0, z = 0, ret = 0;

	__s64 err;



	test1_result = cnt == 1;



	/* valid arguments */

	err = bpf_get_func_arg(ctx, 0, &a);



	/* We need to cast access to traced function argument values with

	 * proper type cast, because trampoline uses type specific instruction

	 * to save it, like for 'int a' with 32-bit mov like:

	 *

	 *   mov %edi,-0x8(%rbp)

	 *

	 * so the upper 4 bytes are not zeroed.

	 */

	test1_result &= err == 0 && ((int) a == 1);



	/* not valid argument */

	err = bpf_get_func_arg(ctx, 1, &z);

	test1_result &= err == -EINVAL;



	/* return value fails in fentry */

	err = bpf_get_func_ret(ctx, &ret);

	test1_result &= err == -EOPNOTSUPP;

	return 0;

}



__u64 test2_result = 0;

SEC("fexit/bpf_fentry_test2")

int BPF_PROG(test2)

{

	__u64 cnt = bpf_get_func_arg_cnt(ctx);

	__u64 a = 0, b = 0, z = 0, ret = 0;

	__s64 err;



	test2_result = cnt == 2;



	/* valid arguments */

	err = bpf_get_func_arg(ctx, 0, &a);

	test2_result &= err == 0 && (int) a == 2;



	err = bpf_get_func_arg(ctx, 1, &b);

	test2_result &= err == 0 && b == 3;



	/* not valid argument */

	err = bpf_get_func_arg(ctx, 2, &z);

	test2_result &= err == -EINVAL;



	/* return value */

	err = bpf_get_func_ret(ctx, &ret);

	test2_result &= err == 0 && ret == 5;

	return 0;

}



__u64 test3_result = 0;

SEC("fmod_ret/bpf_modify_return_test")

int BPF_PROG(fmod_ret_test, int _a, int *_b, int _ret)

{

	__u64 cnt = bpf_get_func_arg_cnt(ctx);

	__u64 a = 0, b = 0, z = 0, ret = 0;

	__s64 err;



	test3_result = cnt == 2;



	/* valid arguments */

	err = bpf_get_func_arg(ctx, 0, &a);

	test3_result &= err == 0 && ((int) a == 1);



	err = bpf_get_func_arg(ctx, 1, &b);

	test3_result &= err == 0 && ((int *) b == _b);



	/* not valid argument */

	err = bpf_get_func_arg(ctx, 2, &z);

	test3_result &= err == -EINVAL;



	/* return value */

	err = bpf_get_func_ret(ctx, &ret);

	test3_result &= err == 0 && ret == 0;



	/* change return value, it's checked in fexit_test program */

	return 1234;

}



__u64 test4_result = 0;

SEC("fexit/bpf_modify_return_test")

int BPF_PROG(fexit_test, int _a, int *_b, int _ret)

{

	__u64 cnt = bpf_get_func_arg_cnt(ctx);

	__u64 a = 0, b = 0, z = 0, ret = 0;

	__s64 err;



	test4_result = cnt == 2;



	/* valid arguments */

	err = bpf_get_func_arg(ctx, 0, &a);

	test4_result &= err == 0 && ((int) a == 1);



	err = bpf_get_func_arg(ctx, 1, &b);

	test4_result &= err == 0 && ((int *) b == _b);



	/* not valid argument */

	err = bpf_get_func_arg(ctx, 2, &z);

	test4_result &= err == -EINVAL;



	/* return value */

	err = bpf_get_func_ret(ctx, &ret);

	test4_result &= err == 0 && ret == 1234;

	return 0;

}