Commit 181b0d1a authored by Eduard Zingerman's avatar Eduard Zingerman Committed by Andrii Nakryiko
Browse files

selftests/bpf: Check if distilled base inherits source endianness 



Create a BTF with endianness different from host, make a distilled
base/split BTF pair from it, dump as raw bytes, import again and
verify that endianness is preserved.

Reviewed-by: default avatarAlan Maguire <alan.maguire@oracle.com>
Tested-by: default avatarAlan Maguire <alan.maguire@oracle.com>
Signed-off-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240830173406.1581007-1-eddyz87@gmail.com
parent da18bfa5

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

+68 −0
Original line number Diff line number Diff line
@@ -535,6 +535,72 @@ static void test_distilled_base_vmlinux(void) 
	btf__free(vmlinux_btf);

}



/* Split and new base BTFs should inherit endianness from source BTF. */

static void test_distilled_endianness(void)

{

	struct btf *base = NULL, *split = NULL, *new_base = NULL, *new_split = NULL;

	struct btf *new_base1 = NULL, *new_split1 = NULL;

	enum btf_endianness inverse_endianness;

	const void *raw_data;

	__u32 size;



	base = btf__new_empty();

	if (!ASSERT_OK_PTR(base, "empty_main_btf"))

		return;

	inverse_endianness = btf__endianness(base) == BTF_LITTLE_ENDIAN ? BTF_BIG_ENDIAN

									: BTF_LITTLE_ENDIAN;

	btf__set_endianness(base, inverse_endianness);

	btf__add_int(base, "int", 4, BTF_INT_SIGNED);   /* [1] int */

	VALIDATE_RAW_BTF(

		base,

		"[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED");

	split = btf__new_empty_split(base);

	if (!ASSERT_OK_PTR(split, "empty_split_btf"))

		goto cleanup;

	btf__add_ptr(split, 1);

	VALIDATE_RAW_BTF(

		split,

		"[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",

		"[2] PTR '(anon)' type_id=1");

	if (!ASSERT_EQ(0, btf__distill_base(split, &new_base, &new_split),

		       "distilled_base") ||

	    !ASSERT_OK_PTR(new_base, "distilled_base") ||

	    !ASSERT_OK_PTR(new_split, "distilled_split") ||

	    !ASSERT_EQ(2, btf__type_cnt(new_base), "distilled_base_type_cnt"))

		goto cleanup;

	VALIDATE_RAW_BTF(

		new_split,

		"[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",

		"[2] PTR '(anon)' type_id=1");



	raw_data = btf__raw_data(new_base, &size);

	if (!ASSERT_OK_PTR(raw_data, "btf__raw_data #1"))

		goto cleanup;

	new_base1 = btf__new(raw_data, size);

	if (!ASSERT_OK_PTR(new_base1, "new_base1 = btf__new()"))

		goto cleanup;

	raw_data = btf__raw_data(new_split, &size);

	if (!ASSERT_OK_PTR(raw_data, "btf__raw_data #2"))

		goto cleanup;

	new_split1 = btf__new_split(raw_data, size, new_base1);

	if (!ASSERT_OK_PTR(new_split1, "new_split1 = btf__new()"))

		goto cleanup;



	ASSERT_EQ(btf__endianness(new_base1), inverse_endianness, "new_base1 endianness");

	ASSERT_EQ(btf__endianness(new_split1), inverse_endianness, "new_split1 endianness");

	VALIDATE_RAW_BTF(

		new_split1,

		"[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",

		"[2] PTR '(anon)' type_id=1");

cleanup:

	btf__free(new_split1);

	btf__free(new_base1);

	btf__free(new_split);

	btf__free(new_base);

	btf__free(split);

	btf__free(base);

}



void test_btf_distill(void)

{

	if (test__start_subtest("distilled_base"))
@@ -549,4 +615,6 @@ void test_btf_distill(void) 
		test_distilled_base_multi_err2();

	if (test__start_subtest("distilled_base_vmlinux"))

		test_distilled_base_vmlinux();

	if (test__start_subtest("distilled_endianness"))

		test_distilled_endianness();

}