Commit 5aab392c authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Alexei Starovoitov
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tools/libbpf: support bigger BTF data sizes 



While it's understandable why kernel limits number of BTF types to 65535
and size of string section to 64KB, in libbpf as user-space library it's
too restrictive. E.g., pahole converting DWARF to BTF type information
for Linux kernel generates more than 3 million BTF types and more than
3MB of strings, before deduplication. So to allow btf__dedup() to do its
work, we need to be able to load bigger BTF sections using btf__new().

Singed-off-by: default avatarAndrii Nakryiko <andriin@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 9d6b3584

tools/lib/bpf/btf.c

+8 −7
Original line number Diff line number Diff line
@@ -16,7 +16,8 @@ 
#define max(a, b) ((a) > (b) ? (a) : (b))

#define min(a, b) ((a) < (b) ? (a) : (b))



#define BTF_MAX_NR_TYPES 65535

#define BTF_MAX_NR_TYPES 0x7fffffff

#define BTF_MAX_STR_OFFSET 0x7fffffff



#define IS_MODIFIER(k) (((k) == BTF_KIND_TYPEDEF) || \

		((k) == BTF_KIND_VOLATILE) || \
@@ -175,7 +176,7 @@ static int btf_parse_str_sec(struct btf *btf) 
	const char *start = btf->nohdr_data + hdr->str_off;

	const char *end = start + btf->hdr->str_len;



	if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET ||

	if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_STR_OFFSET ||

	    start[0] || end[-1]) {

		pr_debug("Invalid BTF string section\n");

		return -EINVAL;
@@ -1882,7 +1883,7 @@ static int btf_dedup_prim_types(struct btf_dedup *d) 
 */

static inline bool is_type_mapped(struct btf_dedup *d, uint32_t type_id)

{

	return d->map[type_id] <= BTF_MAX_TYPE;

	return d->map[type_id] <= BTF_MAX_NR_TYPES;

}



/*
@@ -2033,7 +2034,7 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id, 
	canon_id = resolve_fwd_id(d, canon_id);



	hypot_type_id = d->hypot_map[canon_id];

	if (hypot_type_id <= BTF_MAX_TYPE)

	if (hypot_type_id <= BTF_MAX_NR_TYPES)

		return hypot_type_id == cand_id;



	if (btf_dedup_hypot_map_add(d, canon_id, cand_id))
@@ -2252,7 +2253,7 @@ static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id) 
	__u32 h;



	/* already deduped or is in process of deduping (loop detected) */

	if (d->map[type_id] <= BTF_MAX_TYPE)

	if (d->map[type_id] <= BTF_MAX_NR_TYPES)

		return 0;



	t = d->btf->types[type_id];
@@ -2329,7 +2330,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) 


	if (d->map[type_id] == BTF_IN_PROGRESS_ID)

		return -ELOOP;

	if (d->map[type_id] <= BTF_MAX_TYPE)

	if (d->map[type_id] <= BTF_MAX_NR_TYPES)

		return resolve_type_id(d, type_id);



	t = d->btf->types[type_id];
@@ -2509,7 +2510,7 @@ static int btf_dedup_remap_type_id(struct btf_dedup *d, __u32 type_id) 


	resolved_type_id = resolve_type_id(d, type_id);

	new_type_id = d->hypot_map[resolved_type_id];

	if (new_type_id > BTF_MAX_TYPE)

	if (new_type_id > BTF_MAX_NR_TYPES)

		return -EINVAL;

	return new_type_id;

}

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