Commit 360301a6 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Daniel Borkmann
Browse files

selftests/bpf: Add unit tests for global functions 



test_global_func[12] - check 512 stack limit.
test_global_func[34] - check 8 frame call chain limit.
test_global_func5    - check that non-ctx pointer cannot be passed into
                       a function that expects context.
test_global_func6    - check that ctx pointer is unmodified.
test_global_func7    - check that global function returns scalar.

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarSong Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200110064124.1760511-7-ast@kernel.org
parent e528d1c0

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

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// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2020 Facebook */

#include <test_progs.h>



const char *err_str;

bool found;



static int libbpf_debug_print(enum libbpf_print_level level,

			      const char *format, va_list args)

{

	char *log_buf;



	if (level != LIBBPF_WARN ||

	    strcmp(format, "libbpf: \n%s\n")) {

		vprintf(format, args);

		return 0;

	}



	log_buf = va_arg(args, char *);

	if (!log_buf)

		goto out;

	if (strstr(log_buf, err_str) == 0)

		found = true;

out:

	printf(format, log_buf);

	return 0;

}



extern int extra_prog_load_log_flags;



static int check_load(const char *file)

{

	struct bpf_prog_load_attr attr;

	struct bpf_object *obj = NULL;

	int err, prog_fd;



	memset(&attr, 0, sizeof(struct bpf_prog_load_attr));

	attr.file = file;

	attr.prog_type = BPF_PROG_TYPE_UNSPEC;

	attr.log_level = extra_prog_load_log_flags;

	attr.prog_flags = BPF_F_TEST_RND_HI32;

	found = false;

	err = bpf_prog_load_xattr(&attr, &obj, &prog_fd);

	bpf_object__close(obj);

	return err;

}



struct test_def {

	const char *file;

	const char *err_str;

};



void test_test_global_funcs(void)

{

	struct test_def tests[] = {

		{ "test_global_func1.o", "combined stack size of 4 calls is 544" },

		{ "test_global_func2.o" },

		{ "test_global_func3.o" , "the call stack of 8 frames" },

		{ "test_global_func4.o" },

		{ "test_global_func5.o" , "expected pointer to ctx, but got PTR" },

		{ "test_global_func6.o" , "modified ctx ptr R2" },

		{ "test_global_func7.o" , "foo() doesn't return scalar" },

	};

	libbpf_print_fn_t old_print_fn = NULL;

	int err, i, duration = 0;



	old_print_fn = libbpf_set_print(libbpf_debug_print);



	for (i = 0; i < ARRAY_SIZE(tests); i++) {

		const struct test_def *test = &tests[i];



		if (!test__start_subtest(test->file))

			continue;



		err_str = test->err_str;

		err = check_load(test->file);

		CHECK_FAIL(!!err ^ !!err_str);

		if (err_str)

			CHECK(found, "", "expected string '%s'", err_str);

	}

	libbpf_set_print(old_print_fn);

}

tools/testing/selftests/bpf/progs/test_global_func1.c

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// SPDX-License-Identifier: GPL-2.0-only

/* Copyright (c) 2020 Facebook */

#include <stddef.h>

#include <linux/bpf.h>

#include "bpf_helpers.h"



#ifndef MAX_STACK

#define MAX_STACK (512 - 3 * 32 + 8)

#endif



static __attribute__ ((noinline))

int f0(int var, struct __sk_buff *skb)

{

	return skb->len;

}



__attribute__ ((noinline))

int f1(struct __sk_buff *skb)

{

	volatile char buf[MAX_STACK] = {};



	return f0(0, skb) + skb->len;

}



int f3(int, struct __sk_buff *skb, int);



__attribute__ ((noinline))

int f2(int val, struct __sk_buff *skb)

{

	return f1(skb) + f3(val, skb, 1);

}



__attribute__ ((noinline))

int f3(int val, struct __sk_buff *skb, int var)

{

	volatile char buf[MAX_STACK] = {};



	return skb->ifindex * val * var;

}



SEC("classifier/test")

int test_cls(struct __sk_buff *skb)

{

	return f0(1, skb) + f1(skb) + f2(2, skb) + f3(3, skb, 4);

}

tools/testing/selftests/bpf/progs/test_global_func2.c

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// SPDX-License-Identifier: GPL-2.0-only

/* Copyright (c) 2020 Facebook */

#define MAX_STACK (512 - 3 * 32)

#include "test_global_func1.c"

tools/testing/selftests/bpf/progs/test_global_func3.c

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// SPDX-License-Identifier: GPL-2.0-only

/* Copyright (c) 2020 Facebook */

#include <stddef.h>

#include <linux/bpf.h>

#include "bpf_helpers.h"



__attribute__ ((noinline))

int f1(struct __sk_buff *skb)

{

	return skb->len;

}



__attribute__ ((noinline))

int f2(int val, struct __sk_buff *skb)

{

	return f1(skb) + val;

}



__attribute__ ((noinline))

int f3(int val, struct __sk_buff *skb, int var)

{

	return f2(var, skb) + val;

}



__attribute__ ((noinline))

int f4(struct __sk_buff *skb)

{

	return f3(1, skb, 2);

}



__attribute__ ((noinline))

int f5(struct __sk_buff *skb)

{

	return f4(skb);

}



__attribute__ ((noinline))

int f6(struct __sk_buff *skb)

{

	return f5(skb);

}



__attribute__ ((noinline))

int f7(struct __sk_buff *skb)

{

	return f6(skb);

}



#ifndef NO_FN8

__attribute__ ((noinline))

int f8(struct __sk_buff *skb)

{

	return f7(skb);

}

#endif



SEC("classifier/test")

int test_cls(struct __sk_buff *skb)

{

#ifndef NO_FN8

	return f8(skb);

#else

	return f7(skb);

#endif

}

tools/testing/selftests/bpf/progs/test_global_func4.c

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// SPDX-License-Identifier: GPL-2.0-only

/* Copyright (c) 2020 Facebook */

#define NO_FN8

#include "test_global_func3.c"

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