xref: /linux/tools/testing/selftests/bpf/prog_tests/btf_permute.c (revision c17ee635fd3a482b2ad2bf5e269755c2eae5f25e)

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2026 Xiaomi */

#include <test_progs.h>
#include <bpf/btf.h>
#include "btf_helpers.h"

static void permute_base_check(struct btf *btf)
{
	VALIDATE_RAW_BTF(
		btf,
		"[1] STRUCT 's2' size=4 vlen=1\n"
		"\t'm' type_id=4 bits_offset=0",
		"[2] FUNC 'f' type_id=6 linkage=static",
		"[3] PTR '(anon)' type_id=4",
		"[4] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
		"[5] STRUCT 's1' size=4 vlen=1\n"
		"\t'm' type_id=4 bits_offset=0",
		"[6] FUNC_PROTO '(anon)' ret_type_id=4 vlen=1\n"
		"\t'p' type_id=3");
}

/* Ensure btf__permute works as expected in the base-BTF scenario */
static void test_permute_base(void)
{
	struct btf *btf;
	__u32 permute_ids[7];
	int err;

	btf = btf__new_empty();
	if (!ASSERT_OK_PTR(btf, "empty_main_btf"))
		return;

	btf__add_int(btf, "int", 4, BTF_INT_SIGNED);	/* [1] int */
	btf__add_ptr(btf, 1);				/* [2] ptr to int */
	btf__add_struct(btf, "s1", 4);			/* [3] struct s1 { */
	btf__add_field(btf, "m", 1, 0, 0);		/*       int m; */
							/* } */
	btf__add_struct(btf, "s2", 4);			/* [4] struct s2 { */
	btf__add_field(btf, "m", 1, 0, 0);		/*       int m; */
							/* } */
	btf__add_func_proto(btf, 1);			/* [5] int (*)(int *p); */
	btf__add_func_param(btf, "p", 2);
	btf__add_func(btf, "f", BTF_FUNC_STATIC, 5);	/* [6] int f(int *p); */

	VALIDATE_RAW_BTF(
		btf,
		"[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
		"[2] PTR '(anon)' type_id=1",
		"[3] STRUCT 's1' size=4 vlen=1\n"
		"\t'm' type_id=1 bits_offset=0",
		"[4] STRUCT 's2' size=4 vlen=1\n"
		"\t'm' type_id=1 bits_offset=0",
		"[5] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n"
		"\t'p' type_id=2",
		"[6] FUNC 'f' type_id=5 linkage=static");

	permute_ids[0] = 0; /* [0] -> [0] */
	permute_ids[1] = 4; /* [1] -> [4] */
	permute_ids[2] = 3; /* [2] -> [3] */
	permute_ids[3] = 5; /* [3] -> [5] */
	permute_ids[4] = 1; /* [4] -> [1] */
	permute_ids[5] = 6; /* [5] -> [6] */
	permute_ids[6] = 2; /* [6] -> [2] */
	err = btf__permute(btf, permute_ids, ARRAY_SIZE(permute_ids), NULL);
	if (!ASSERT_OK(err, "btf__permute_base"))
		goto done;
	permute_base_check(btf);

	/* ids[0] must be 0 for base BTF */
	permute_ids[0] = 4; /* [0] -> [0] */
	permute_ids[1] = 0; /* [1] -> [4] */
	permute_ids[2] = 3; /* [2] -> [3] */
	permute_ids[3] = 5; /* [3] -> [5] */
	permute_ids[4] = 1; /* [4] -> [1] */
	permute_ids[5] = 6; /* [5] -> [6] */
	permute_ids[6] = 2; /* [6] -> [2] */
	err = btf__permute(btf, permute_ids, ARRAY_SIZE(permute_ids), NULL);
	if (!ASSERT_ERR(err, "btf__permute_base"))
		goto done;
	/* BTF is not modified */
	permute_base_check(btf);

	/* id_map_cnt is invalid */
	permute_ids[0] = 0; /* [0] -> [0] */
	permute_ids[1] = 4; /* [1] -> [4] */
	permute_ids[2] = 3; /* [2] -> [3] */
	permute_ids[3] = 5; /* [3] -> [5] */
	permute_ids[4] = 1; /* [4] -> [1] */
	permute_ids[5] = 6; /* [5] -> [6] */
	permute_ids[6] = 2; /* [6] -> [2] */
	err = btf__permute(btf, permute_ids, ARRAY_SIZE(permute_ids) - 1, NULL);
	if (!ASSERT_ERR(err, "btf__permute_base"))
		goto done;
	/* BTF is not modified */
	permute_base_check(btf);

	/* Multiple types can not be mapped to the same ID */
	permute_ids[0] = 0;
	permute_ids[1] = 4;
	permute_ids[2] = 4;
	permute_ids[3] = 5;
	permute_ids[4] = 1;
	permute_ids[5] = 6;
	permute_ids[6] = 2;
	err = btf__permute(btf, permute_ids, ARRAY_SIZE(permute_ids), NULL);
	if (!ASSERT_ERR(err, "btf__permute_base"))
		goto done;
	/* BTF is not modified */
	permute_base_check(btf);

	/* Type ID must be valid */
	permute_ids[0] = 0;
	permute_ids[1] = 4;
	permute_ids[2] = 3;
	permute_ids[3] = 5;
	permute_ids[4] = 1;
	permute_ids[5] = 7;
	permute_ids[6] = 2;
	err = btf__permute(btf, permute_ids, ARRAY_SIZE(permute_ids), NULL);
	if (!ASSERT_ERR(err, "btf__permute_base"))
		goto done;
	/* BTF is not modified */
	permute_base_check(btf);

done:
	btf__free(btf);
}

static void permute_split_check(struct btf *btf)
{
	VALIDATE_RAW_BTF(
		btf,
		"[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
		"[2] PTR '(anon)' type_id=1",
		"[3] STRUCT 's2' size=4 vlen=1\n"
		"\t'm' type_id=1 bits_offset=0",
		"[4] FUNC 'f' type_id=5 linkage=static",
		"[5] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n"
		"\t'p' type_id=2",
		"[6] STRUCT 's1' size=4 vlen=1\n"
		"\t'm' type_id=1 bits_offset=0");
}

/* Ensure btf__permute works as expected in the split-BTF scenario */
static void test_permute_split(void)
{
	struct btf *split_btf = NULL, *base_btf = NULL;
	__u32 permute_ids[4];
	int err, start_id;

	base_btf = btf__new_empty();
	if (!ASSERT_OK_PTR(base_btf, "empty_main_btf"))
		return;

	btf__add_int(base_btf, "int", 4, BTF_INT_SIGNED);	/* [1] int */
	btf__add_ptr(base_btf, 1);				/* [2] ptr to int */
	VALIDATE_RAW_BTF(
		base_btf,
		"[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
		"[2] PTR '(anon)' type_id=1");
	split_btf = btf__new_empty_split(base_btf);
	if (!ASSERT_OK_PTR(split_btf, "empty_split_btf"))
		goto cleanup;
	btf__add_struct(split_btf, "s1", 4);			/* [3] struct s1 { */
	btf__add_field(split_btf, "m", 1, 0, 0);		/*   int m; */
								/* } */
	btf__add_struct(split_btf, "s2", 4);			/* [4] struct s2 { */
	btf__add_field(split_btf, "m", 1, 0, 0);		/*   int m; */
								/* } */
	btf__add_func_proto(split_btf, 1);			/* [5] int (*)(int p); */
	btf__add_func_param(split_btf, "p", 2);
	btf__add_func(split_btf, "f", BTF_FUNC_STATIC, 5);	/* [6] int f(int *p); */

	VALIDATE_RAW_BTF(
		split_btf,
		"[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
		"[2] PTR '(anon)' type_id=1",
		"[3] STRUCT 's1' size=4 vlen=1\n"
		"\t'm' type_id=1 bits_offset=0",
		"[4] STRUCT 's2' size=4 vlen=1\n"
		"\t'm' type_id=1 bits_offset=0",
		"[5] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n"
		"\t'p' type_id=2",
		"[6] FUNC 'f' type_id=5 linkage=static");

	start_id = btf__type_cnt(base_btf);
	permute_ids[3 - start_id] = 6; /* [3] -> [6] */
	permute_ids[4 - start_id] = 3; /* [4] -> [3] */
	permute_ids[5 - start_id] = 5; /* [5] -> [5] */
	permute_ids[6 - start_id] = 4; /* [6] -> [4] */
	err = btf__permute(split_btf, permute_ids, ARRAY_SIZE(permute_ids), NULL);
	if (!ASSERT_OK(err, "btf__permute_split"))
		goto cleanup;
	permute_split_check(split_btf);

	/*
	 * For split BTF, id_map_cnt must equal to the number of types
	 * added on top of base BTF
	 */
	permute_ids[3 - start_id] = 4;
	permute_ids[4 - start_id] = 3;
	permute_ids[5 - start_id] = 5;
	permute_ids[6 - start_id] = 6;
	err = btf__permute(split_btf, permute_ids, ARRAY_SIZE(permute_ids) - 1, NULL);
	if (!ASSERT_ERR(err, "btf__permute_split"))
		goto cleanup;
	/* BTF is not modified */
	permute_split_check(split_btf);

	/* Multiple types can not be mapped to the same ID */
	permute_ids[3 - start_id] = 4;
	permute_ids[4 - start_id] = 3;
	permute_ids[5 - start_id] = 3;
	permute_ids[6 - start_id] = 6;
	err = btf__permute(split_btf, permute_ids, ARRAY_SIZE(permute_ids), NULL);
	if (!ASSERT_ERR(err, "btf__permute_split"))
		goto cleanup;
	/* BTF is not modified */
	permute_split_check(split_btf);

	/* Can not map to base ID */
	permute_ids[3 - start_id] = 4;
	permute_ids[4 - start_id] = 2;
	permute_ids[5 - start_id] = 5;
	permute_ids[6 - start_id] = 6;
	err = btf__permute(split_btf, permute_ids, ARRAY_SIZE(permute_ids), NULL);
	if (!ASSERT_ERR(err, "btf__permute_split"))
		goto cleanup;
	/* BTF is not modified */
	permute_split_check(split_btf);

cleanup:
	btf__free(split_btf);
	btf__free(base_btf);
}

void test_btf_permute(void)
{
	if (test__start_subtest("permute_base"))
		test_permute_base();
	if (test__start_subtest("permute_split"))
		test_permute_split();
}