selftests/bpf: allow BTF specs and func infos in test_verifier tests

The BTF and func_info specification for test_verifier tests follows
the same notation as in prog_tests/btf.c tests. E.g.:

  ...
  .func_info = { { 0, 6 }, { 8, 7 } },
  .func_info_cnt = 2,
  .btf_strings = "\0int\0",
  .btf_types = {
    BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),
    BTF_PTR_ENC(1),
  },
  ...

The BTF specification is loaded only when specified.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/r/20220620235344.569325-3-eddyz87@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

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

@@ -34,7 +34,6 @@ static bool always_log;
 #undef CHECK
 #define CHECK(condition, format...) _CHECK(condition, "check", duration, format)
 
-#define BTF_END_RAW 0xdeadbeef
 #define NAME_TBD 0xdeadb33f
 
 #define NAME_NTH(N) (0xfffe0000 | N)

tools/testing/selftests/bpf/test_btf.h

@@ -4,6 +4,8 @@
 #ifndef _TEST_BTF_H
 #define _TEST_BTF_H
 
+#define BTF_END_RAW 0xdeadbeef
+
 #define BTF_INFO_ENC(kind, kind_flag, vlen)			\
 	((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN))
 

tools/testing/selftests/bpf/test_verifier.c

@@ -59,11 +59,17 @@
 #define MAX_TEST_RUNS	8
 #define POINTER_VALUE	0xcafe4all
 #define TEST_DATA_LEN	64
+#define MAX_FUNC_INFOS	8
+#define MAX_BTF_STRINGS	256
+#define MAX_BTF_TYPES	256
 
 #define INSN_OFF_MASK	((__s16)0xFFFF)
 #define INSN_IMM_MASK	((__s32)0xFFFFFFFF)
 #define SKIP_INSNS()	BPF_RAW_INSN(0xde, 0xa, 0xd, 0xbeef, 0xdeadbeef)
 
+#define DEFAULT_LIBBPF_LOG_LEVEL	4
+#define VERBOSE_LIBBPF_LOG_LEVEL	1
+
 #define F_NEEDS_EFFICIENT_UNALIGNED_ACCESS	(1 << 0)
 #define F_LOAD_WITH_STRICT_ALIGNMENT		(1 << 1)
 
@@ -158,6 +164,14 @@ struct bpf_test {
 	};
 	enum bpf_attach_type expected_attach_type;
 	const char *kfunc;
+	struct bpf_func_info func_info[MAX_FUNC_INFOS];
+	int func_info_cnt;
+	char btf_strings[MAX_BTF_STRINGS];
+	/* A set of BTF types to load when specified,
+	 * use macro definitions from test_btf.h,
+	 * must end with BTF_END_RAW
+	 */
+	__u32 btf_types[MAX_BTF_TYPES];
 };
 
 /* Note we want this to be 64 bit aligned so that the end of our array is
@@ -687,34 +701,66 @@ static __u32 btf_raw_types[] = {
 	BTF_MEMBER_ENC(71, 13, 128), /* struct prog_test_member __kptr_ref *ptr; */
 };
 
-static int load_btf(void)
+static char bpf_vlog[UINT_MAX >> 8];
+
+static int load_btf_spec(__u32 *types, int types_len,
+			 const char *strings, int strings_len)
 {
 	struct btf_header hdr = {
 		.magic = BTF_MAGIC,
 		.version = BTF_VERSION,
 		.hdr_len = sizeof(struct btf_header),
-		.type_len = sizeof(btf_raw_types),
-		.str_off = sizeof(btf_raw_types),
-		.str_len = sizeof(btf_str_sec),
+		.type_len = types_len,
+		.str_off = types_len,
+		.str_len = strings_len,
 	};
 	void *ptr, *raw_btf;
 	int btf_fd;
+	LIBBPF_OPTS(bpf_btf_load_opts, opts,
+		    .log_buf = bpf_vlog,
+		    .log_size = sizeof(bpf_vlog),
+		    .log_level = (verbose
+				  ? VERBOSE_LIBBPF_LOG_LEVEL
+				  : DEFAULT_LIBBPF_LOG_LEVEL),
+	);
 
-	ptr = raw_btf = malloc(sizeof(hdr) + sizeof(btf_raw_types) +
-			       sizeof(btf_str_sec));
+	raw_btf = malloc(sizeof(hdr) + types_len + strings_len);
 
+	ptr = raw_btf;
 	memcpy(ptr, &hdr, sizeof(hdr));
 	ptr += sizeof(hdr);
-	memcpy(ptr, btf_raw_types, hdr.type_len);
+	memcpy(ptr, types, hdr.type_len);
 	ptr += hdr.type_len;
-	memcpy(ptr, btf_str_sec, hdr.str_len);
+	memcpy(ptr, strings, hdr.str_len);
 	ptr += hdr.str_len;
 
-	btf_fd = bpf_btf_load(raw_btf, ptr - raw_btf, NULL);
-	free(raw_btf);
+	btf_fd = bpf_btf_load(raw_btf, ptr - raw_btf, &opts);
 	if (btf_fd < 0)
-		return -1;
-	return btf_fd;
+		printf("Failed to load BTF spec: '%s'\n", strerror(errno));
+
+	free(raw_btf);
+
+	return btf_fd < 0 ? -1 : btf_fd;
+}
+
+static int load_btf(void)
+{
+	return load_btf_spec(btf_raw_types, sizeof(btf_raw_types),
+			     btf_str_sec, sizeof(btf_str_sec));
+}
+
+static int load_btf_for_test(struct bpf_test *test)
+{
+	int types_num = 0;
+
+	while (types_num < MAX_BTF_TYPES &&
+	       test->btf_types[types_num] != BTF_END_RAW)
+		++types_num;
+
+	int types_len = types_num * sizeof(test->btf_types[0]);
+
+	return load_btf_spec(test->btf_types, types_len,
+			     test->btf_strings, sizeof(test->btf_strings));
 }
 
 static int create_map_spin_lock(void)
@@ -793,8 +839,6 @@ static int create_map_kptr(void)
 	return fd;
 }
 
-static char bpf_vlog[UINT_MAX >> 8];
-
 static void do_test_fixup(struct bpf_test *test, enum bpf_prog_type prog_type,
 			  struct bpf_insn *prog, int *map_fds)
 {
@@ -1360,7 +1404,7 @@ static bool check_xlated_program(struct bpf_test *test, int fd_prog)
 static void do_test_single(struct bpf_test *test, bool unpriv,
 			   int *passes, int *errors)
 {
-	int fd_prog, expected_ret, alignment_prevented_execution;
+	int fd_prog, btf_fd, expected_ret, alignment_prevented_execution;
 	int prog_len, prog_type = test->prog_type;
 	struct bpf_insn *prog = test->insns;
 	LIBBPF_OPTS(bpf_prog_load_opts, opts);
@@ -1372,8 +1416,10 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
 	__u32 pflags;
 	int i, err;
 
+	fd_prog = -1;
 	for (i = 0; i < MAX_NR_MAPS; i++)
 		map_fds[i] = -1;
+	btf_fd = -1;
 
 	if (!prog_type)
 		prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
@@ -1406,11 +1452,11 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
 
 	opts.expected_attach_type = test->expected_attach_type;
 	if (verbose)
-		opts.log_level = 1;
+		opts.log_level = VERBOSE_LIBBPF_LOG_LEVEL;
 	else if (expected_ret == VERBOSE_ACCEPT)
 		opts.log_level = 2;
 	else
-		opts.log_level = 4;
+		opts.log_level = DEFAULT_LIBBPF_LOG_LEVEL;
 	opts.prog_flags = pflags;
 
 	if (prog_type == BPF_PROG_TYPE_TRACING && test->kfunc) {
@@ -1428,6 +1474,19 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
 		opts.attach_btf_id = attach_btf_id;
 	}
 
+	if (test->btf_types[0] != 0) {
+		btf_fd = load_btf_for_test(test);
+		if (btf_fd < 0)
+			goto fail_log;
+		opts.prog_btf_fd = btf_fd;
+	}
+
+	if (test->func_info_cnt != 0) {
+		opts.func_info = test->func_info;
+		opts.func_info_cnt = test->func_info_cnt;
+		opts.func_info_rec_size = sizeof(test->func_info[0]);
+	}
+
 	opts.log_buf = bpf_vlog;
 	opts.log_size = sizeof(bpf_vlog);
 	fd_prog = bpf_prog_load(prog_type, NULL, "GPL", prog, prog_len, &opts);
@@ -1539,6 +1598,7 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
 	if (test->fill_insns)
 		free(test->fill_insns);
 	close(fd_prog);
+	close(btf_fd);
 	for (i = 0; i < MAX_NR_MAPS; i++)
 		close(map_fds[i]);
 	sched_yield();