diff options
Diffstat (limited to 'tools/lib/bpf/btf.c')
| -rw-r--r-- | tools/lib/bpf/btf.c | 881 |
1 files changed, 516 insertions, 365 deletions
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 231b07203e3d..3c3f2bc6c652 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -78,10 +78,32 @@ struct btf { void *types_data; size_t types_data_cap; /* used size stored in hdr->type_len */ - /* type ID to `struct btf_type *` lookup index */ + /* type ID to `struct btf_type *` lookup index + * type_offs[0] corresponds to the first non-VOID type: + * - for base BTF it's type [1]; + * - for split BTF it's the first non-base BTF type. + */ __u32 *type_offs; size_t type_offs_cap; + /* number of types in this BTF instance: + * - doesn't include special [0] void type; + * - for split BTF counts number of types added on top of base BTF. + */ __u32 nr_types; + /* if not NULL, points to the base BTF on top of which the current + * split BTF is based + */ + struct btf *base_btf; + /* BTF type ID of the first type in this BTF instance: + * - for base BTF it's equal to 1; + * - for split BTF it's equal to biggest type ID of base BTF plus 1. + */ + int start_id; + /* logical string offset of this BTF instance: + * - for base BTF it's equal to 0; + * - for split BTF it's equal to total size of base BTF's string section size. + */ + int start_str_off; void *strs_data; size_t strs_data_cap; /* used size stored in hdr->str_len */ @@ -90,6 +112,14 @@ struct btf { struct hashmap *strs_hash; /* whether strings are already deduplicated */ bool strs_deduped; + /* extra indirection layer to make strings hashmap work with stable + * string offsets and ability to transparently choose between + * btf->strs_data or btf_dedup->strs_data as a source of strings. + * This is used for BTF strings dedup to transfer deduplicated strings + * data back to struct btf without re-building strings index. + */ + void **strs_data_ptr; + /* BTF object FD, if loaded into kernel */ int fd; @@ -168,7 +198,7 @@ static int btf_add_type_idx_entry(struct btf *btf, __u32 type_off) __u32 *p; p = btf_add_mem((void **)&btf->type_offs, &btf->type_offs_cap, sizeof(__u32), - btf->nr_types + 1, BTF_MAX_NR_TYPES, 1); + btf->nr_types, BTF_MAX_NR_TYPES, 1); if (!p) return -ENOMEM; @@ -215,22 +245,18 @@ static int btf_parse_hdr(struct btf *btf) return -EINVAL; } - if (meta_left < hdr->type_off) { - pr_debug("Invalid BTF type section offset:%u\n", hdr->type_off); + if (meta_left < hdr->str_off + hdr->str_len) { + pr_debug("Invalid BTF total size:%u\n", btf->raw_size); return -EINVAL; } - if (meta_left < hdr->str_off) { - pr_debug("Invalid BTF string section offset:%u\n", hdr->str_off); + if (hdr->type_off + hdr->type_len > hdr->str_off) { + pr_debug("Invalid BTF data sections layout: type data at %u + %u, strings data at %u + %u\n", + hdr->type_off, hdr->type_len, hdr->str_off, hdr->str_len); return -EINVAL; } - if (hdr->type_off >= hdr->str_off) { - pr_debug("BTF type section offset >= string section offset. No type?\n"); - return -EINVAL; - } - - if (hdr->type_off & 0x02) { + if (hdr->type_off % 4) { pr_debug("BTF type section is not aligned to 4 bytes\n"); return -EINVAL; } @@ -244,12 +270,16 @@ static int btf_parse_str_sec(struct btf *btf) const char *start = btf->strs_data; const char *end = start + btf->hdr->str_len; - if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_STR_OFFSET || - start[0] || end[-1]) { + if (btf->base_btf && hdr->str_len == 0) + return 0; + if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_STR_OFFSET || end[-1]) { + pr_debug("Invalid BTF string section\n"); + return -EINVAL; + } + if (!btf->base_btf && start[0]) { pr_debug("Invalid BTF string section\n"); return -EINVAL; } - return 0; } @@ -364,19 +394,9 @@ static int btf_parse_type_sec(struct btf *btf) struct btf_header *hdr = btf->hdr; void *next_type = btf->types_data; void *end_type = next_type + hdr->type_len; - int err, i = 0, type_size; - - /* VOID (type_id == 0) is specially handled by btf__get_type_by_id(), - * so ensure we can never properly use its offset from index by - * setting it to a large value - */ - err = btf_add_type_idx_entry(btf, UINT_MAX); - if (err) - return err; + int err, type_size; while (next_type + sizeof(struct btf_type) <= end_type) { - i++; - if (btf->swapped_endian) btf_bswap_type_base(next_type); @@ -384,7 +404,7 @@ static int btf_parse_type_sec(struct btf *btf) if (type_size < 0) return type_size; if (next_type + type_size > end_type) { - pr_warn("BTF type [%d] is malformed\n", i); + pr_warn("BTF type [%d] is malformed\n", btf->start_id + btf->nr_types); return -EINVAL; } @@ -409,7 +429,12 @@ static int btf_parse_type_sec(struct btf *btf) __u32 btf__get_nr_types(const struct btf *btf) { - return btf->nr_types; + return btf->start_id + btf->nr_types - 1; +} + +const struct btf *btf__base_btf(const struct btf *btf) +{ + return btf->base_btf; } /* internal helper returning non-const pointer to a type */ @@ -417,13 +442,14 @@ static struct btf_type *btf_type_by_id(struct btf *btf, __u32 type_id) { if (type_id == 0) return &btf_void; - - return btf->types_data + btf->type_offs[type_id]; + if (type_id < btf->start_id) + return btf_type_by_id(btf->base_btf, type_id); + return btf->types_data + btf->type_offs[type_id - btf->start_id]; } const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 type_id) { - if (type_id > btf->nr_types) + if (type_id >= btf->start_id + btf->nr_types) return NULL; return btf_type_by_id((struct btf *)btf, type_id); } @@ -432,9 +458,13 @@ static int determine_ptr_size(const struct btf *btf) { const struct btf_type *t; const char *name; - int i; + int i, n; - for (i = 1; i <= btf->nr_types; i++) { + if (btf->base_btf && btf->base_btf->ptr_sz > 0) + return btf->base_btf->ptr_sz; + + n = btf__get_nr_types(btf); + for (i = 1; i <= n; i++) { t = btf__type_by_id(btf, i); if (!btf_is_int(t)) continue; @@ -649,12 +679,12 @@ int btf__resolve_type(const struct btf *btf, __u32 type_id) __s32 btf__find_by_name(const struct btf *btf, const char *type_name) { - __u32 i; + __u32 i, nr_types = btf__get_nr_types(btf); if (!strcmp(type_name, "void")) return 0; - for (i = 1; i <= btf->nr_types; i++) { + for (i = 1; i <= nr_types; i++) { const struct btf_type *t = btf__type_by_id(btf, i); const char *name = btf__name_by_offset(btf, t->name_off); @@ -668,12 +698,12 @@ __s32 btf__find_by_name(const struct btf *btf, const char *type_name) __s32 btf__find_by_name_kind(const struct btf *btf, const char *type_name, __u32 kind) { - __u32 i; + __u32 i, nr_types = btf__get_nr_types(btf); if (kind == BTF_KIND_UNKN || !strcmp(type_name, "void")) return 0; - for (i = 1; i <= btf->nr_types; i++) { + for (i = 1; i <= nr_types; i++) { const struct btf_type *t = btf__type_by_id(btf, i); const char *name; @@ -717,7 +747,7 @@ void btf__free(struct btf *btf) free(btf); } -struct btf *btf__new_empty(void) +static struct btf *btf_new_empty(struct btf *base_btf) { struct btf *btf; @@ -725,12 +755,21 @@ struct btf *btf__new_empty(void) if (!btf) return ERR_PTR(-ENOMEM); + btf->nr_types = 0; + btf->start_id = 1; + btf->start_str_off = 0; btf->fd = -1; btf->ptr_sz = sizeof(void *); btf->swapped_endian = false; + if (base_btf) { + btf->base_btf = base_btf; + btf->start_id = btf__get_nr_types(base_btf) + 1; + btf->start_str_off = base_btf->hdr->str_len; + } + /* +1 for empty string at offset 0 */ - btf->raw_size = sizeof(struct btf_header) + 1; + btf->raw_size = sizeof(struct btf_header) + (base_btf ? 0 : 1); btf->raw_data = calloc(1, btf->raw_size); if (!btf->raw_data) { free(btf); @@ -744,12 +783,22 @@ struct btf *btf__new_empty(void) btf->types_data = btf->raw_data + btf->hdr->hdr_len; btf->strs_data = btf->raw_data + btf->hdr->hdr_len; - btf->hdr->str_len = 1; /* empty string at offset 0 */ + btf->hdr->str_len = base_btf ? 0 : 1; /* empty string at offset 0 */ return btf; } -struct btf *btf__new(const void *data, __u32 size) +struct btf *btf__new_empty(void) +{ + return btf_new_empty(NULL); +} + +struct btf *btf__new_empty_split(struct btf *base_btf) +{ + return btf_new_empty(base_btf); +} + +static struct btf *btf_new(const void *data, __u32 size, struct btf *base_btf) { struct btf *btf; int err; @@ -758,6 +807,16 @@ struct btf *btf__new(const void *data, __u32 size) if (!btf) return ERR_PTR(-ENOMEM); + btf->nr_types = 0; + btf->start_id = 1; + btf->start_str_off = 0; + + if (base_btf) { + btf->base_btf = base_btf; + btf->start_id = btf__get_nr_types(base_btf) + 1; + btf->start_str_off = base_btf->hdr->str_len; + } + btf->raw_data = malloc(size); if (!btf->raw_data) { err = -ENOMEM; @@ -790,7 +849,13 @@ done: return btf; } -struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext) +struct btf *btf__new(const void *data, __u32 size) +{ + return btf_new(data, size, NULL); +} + +static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, + struct btf_ext **btf_ext) { Elf_Data *btf_data = NULL, *btf_ext_data = NULL; int err = 0, fd = -1, idx = 0; @@ -868,7 +933,7 @@ struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext) err = -ENOENT; goto done; } - btf = btf__new(btf_data->d_buf, btf_data->d_size); + btf = btf_new(btf_data->d_buf, btf_data->d_size, base_btf); if (IS_ERR(btf)) goto done; @@ -913,7 +978,17 @@ done: return btf; } -struct btf *btf__parse_raw(const char *path) +struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext) +{ + return btf_parse_elf(path, NULL, btf_ext); +} + +struct btf *btf__parse_elf_split(const char *path, struct btf *base_btf) +{ + return btf_parse_elf(path, base_btf, NULL); +} + +static struct btf *btf_parse_raw(const char *path, struct btf *base_btf) { struct btf *btf = NULL; void *data = NULL; @@ -967,7 +1042,7 @@ struct btf *btf__parse_raw(const char *path) } /* finally parse BTF data */ - btf = btf__new(data, sz); + btf = btf_new(data, sz, base_btf); err_out: free(data); @@ -976,18 +1051,38 @@ err_out: return err ? ERR_PTR(err) : btf; } -struct btf *btf__parse(const char *path, struct btf_ext **btf_ext) +struct btf *btf__parse_raw(const char *path) +{ + return btf_parse_raw(path, NULL); +} + +struct btf *btf__parse_raw_split(const char *path, struct btf *base_btf) +{ + return btf_parse_raw(path, base_btf); +} + +static struct btf *btf_parse(const char *path, struct btf *base_btf, struct btf_ext **btf_ext) { struct btf *btf; if (btf_ext) *btf_ext = NULL; - btf = btf__parse_raw(path); + btf = btf_parse_raw(path, base_btf); if (!IS_ERR(btf) || PTR_ERR(btf) != -EPROTO) return btf; - return btf__parse_elf(path, btf_ext); + return btf_parse_elf(path, base_btf, btf_ext); +} + +struct btf *btf__parse(const char *path, struct btf_ext **btf_ext) +{ + return btf_parse(path, NULL, btf_ext); +} + +struct btf *btf__parse_split(const char *path, struct btf *base_btf) +{ + return btf_parse(path, base_btf, NULL); } static int compare_vsi_off(const void *_a, const void *_b) @@ -1171,8 +1266,8 @@ static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endi memcpy(p, btf->types_data, hdr->type_len); if (swap_endian) { - for (i = 1; i <= btf->nr_types; i++) { - t = p + btf->type_offs[i]; + for (i = 0; i < btf->nr_types; i++) { + t = p + btf->type_offs[i]; /* btf_bswap_type_rest() relies on native t->info, so * we swap base type info after we swapped all the * additional information @@ -1215,8 +1310,10 @@ const void *btf__get_raw_data(const struct btf *btf_ro, __u32 *size) const char *btf__str_by_offset(const struct btf *btf, __u32 offset) { - if (offset < btf->hdr->str_len) - return btf->strs_data + offset; + if (offset < btf->start_str_off) + return btf__str_by_offset(btf->base_btf, offset); + else if (offset - btf->start_str_off < btf->hdr->str_len) + return btf->strs_data + (offset - btf->start_str_off); else return NULL; } @@ -1226,35 +1323,27 @@ const char *btf__name_by_offset(const struct btf *btf, __u32 offset) return btf__str_by_offset(btf, offset); } -int btf__get_from_id(__u32 id, struct btf **btf) +struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf) { - struct bpf_btf_info btf_info = { 0 }; + struct bpf_btf_info btf_info; __u32 len = sizeof(btf_info); __u32 last_size; - int btf_fd; + struct btf *btf; void *ptr; int err; - err = 0; - *btf = NULL; - btf_fd = bpf_btf_get_fd_by_id(id); - if (btf_fd < 0) - return 0; - /* we won't know btf_size until we call bpf_obj_get_info_by_fd(). so * let's start with a sane default - 4KiB here - and resize it only if * bpf_obj_get_info_by_fd() needs a bigger buffer. */ - btf_info.btf_size = 4096; - last_size = btf_info.btf_size; + last_size = 4096; ptr = malloc(last_size); - if (!ptr) { - err = -ENOMEM; - goto exit_free; - } + if (!ptr) + return ERR_PTR(-ENOMEM); - memset(ptr, 0, last_size); + memset(&btf_info, 0, sizeof(btf_info)); btf_info.btf = ptr_to_u64(ptr); + btf_info.btf_size = last_size; err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len); if (!err && btf_info.btf_size > last_size) { @@ -1263,31 +1352,48 @@ int btf__get_from_id(__u32 id, struct btf **btf) last_size = btf_info.btf_size; temp_ptr = realloc(ptr, last_size); if (!temp_ptr) { - err = -ENOMEM; + btf = ERR_PTR(-ENOMEM); goto exit_free; } ptr = temp_ptr; - memset(ptr, 0, last_size); + + len = sizeof(btf_info); + memset(&btf_info, 0, sizeof(btf_info)); btf_info.btf = ptr_to_u64(ptr); + btf_info.btf_size = last_size; + err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len); } if (err || btf_info.btf_size > last_size) { - err = errno; + btf = err ? ERR_PTR(-errno) : ERR_PTR(-E2BIG); goto exit_free; } - *btf = btf__new((__u8 *)(long)btf_info.btf, btf_info.btf_size); - if (IS_ERR(*btf)) { - err = PTR_ERR(*btf); - *btf = NULL; - } + btf = btf_new(ptr, btf_info.btf_size, base_btf); exit_free: - close(btf_fd); free(ptr); + return btf; +} - return err; +int btf__get_from_id(__u32 id, struct btf **btf) +{ + struct btf *res; + int btf_fd; + + *btf = NULL; + btf_fd = bpf_btf_get_fd_by_id(id); + if (btf_fd < 0) + return -errno; + + res = btf_get_from_fd(btf_fd, NULL); + close(btf_fd); + if (IS_ERR(res)) + return PTR_ERR(res); + + *btf = res; + return 0; } int btf__get_map_kv_tids(const struct btf *btf, const char *map_name, @@ -1363,17 +1469,19 @@ int btf__get_map_kv_tids(const struct btf *btf, const char *map_name, static size_t strs_hash_fn(const void *key, void *ctx) { - struct btf *btf = ctx; - const char *str = btf->strs_data + (long)key; + const struct btf *btf = ctx; + const char *strs = *btf->strs_data_ptr; + const char *str = strs + (long)key; return str_hash(str); } static bool strs_hash_equal_fn(const void *key1, const void *key2, void *ctx) { - struct btf *btf = ctx; - const char *str1 = btf->strs_data + (long)key1; - const char *str2 = btf->strs_data + (long)key2; + const struct btf *btf = ctx; + const char *strs = *btf->strs_data_ptr; + const char *str1 = strs + (long)key1; + const char *str2 = strs + (long)key2; return strcmp(str1, str2) == 0; } @@ -1418,6 +1526,9 @@ static int btf_ensure_modifiable(struct btf *btf) memcpy(types, btf->types_data, btf->hdr->type_len); memcpy(strs, btf->strs_data, btf->hdr->str_len); + /* make hashmap below use btf->strs_data as a source of strings */ + btf->strs_data_ptr = &btf->strs_data; + /* build lookup index for all strings */ hash = hashmap__new(strs_hash_fn, strs_hash_equal_fn, btf); if (IS_ERR(hash)) { @@ -1448,7 +1559,10 @@ static int btf_ensure_modifiable(struct btf *btf) /* if BTF was created from scratch, all strings are guaranteed to be * unique and deduplicated */ - btf->strs_deduped = btf->hdr->str_len <= 1; + if (btf->hdr->str_len == 0) + btf->strs_deduped = true; + if (!btf->base_btf && btf->hdr->str_len == 1) + btf->strs_deduped = true; /* invalidate raw_data representation */ btf_invalidate_raw_data(btf); @@ -1480,6 +1594,14 @@ int btf__find_str(struct btf *btf, const char *s) long old_off, new_off, len; void *p; + if (btf->base_btf) { + int ret; + + ret = btf__find_str(btf->base_btf, s); + if (ret != -ENOENT) + return ret; + } + /* BTF needs to be in a modifiable state to build string lookup index */ if (btf_ensure_modifiable(btf)) return -ENOMEM; @@ -1494,7 +1616,7 @@ int btf__find_str(struct btf *btf, const char *s) memcpy(p, s, len); if (hashmap__find(btf->strs_hash, (void *)new_off, (void **)&old_off)) - return old_off; + return btf->start_str_off + old_off; return -ENOENT; } @@ -1510,6 +1632,14 @@ int btf__add_str(struct btf *btf, const char *s) void *p; int err; + if (btf->base_btf) { + int ret; + + ret = btf__find_str(btf->base_btf, s); + if (ret != -ENOENT) + return ret; + } + if (btf_ensure_modifiable(btf)) return -ENOMEM; @@ -1536,12 +1666,12 @@ int btf__add_str(struct btf *btf, const char *s) err = hashmap__insert(btf->strs_hash, (void *)new_off, (void *)new_off, HASHMAP_ADD, (const void **)&old_off, NULL); if (err == -EEXIST) - return old_off; /* duplicated string, return existing offset */ + return btf->start_str_off + old_off; /* duplicated string, return existing offset */ if (err) return err; btf->hdr->str_len += len; /* new unique string, adjust data length */ - return new_off; + return btf->start_str_off + new_off; } static void *btf_add_type_mem(struct btf *btf, size_t add_sz) @@ -1560,6 +1690,20 @@ static void btf_type_inc_vlen(struct btf_type *t) t->info = btf_type_info(btf_kind(t), btf_vlen(t) + 1, btf_kflag(t)); } +static int btf_commit_type(struct btf *btf, int data_sz) +{ + int err; + + err = btf_add_type_idx_entry(btf, btf->hdr->type_len); + if (err) + return err; + + btf->hdr->type_len += data_sz; + btf->hdr->str_off += data_sz; + btf->nr_types++; + return btf->start_id + btf->nr_types - 1; +} + /* * Append new BTF_KIND_INT type with: * - *name* - non-empty, non-NULL type name; @@ -1572,7 +1716,7 @@ static void btf_type_inc_vlen(struct btf_type *t) int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding) { struct btf_type *t; - int sz, err, name_off; + int sz, name_off; /* non-empty name */ if (!name || !name[0]) @@ -1606,14 +1750,7 @@ int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding /* set INT info, we don't allow setting legacy bit offset/size */ *(__u32 *)(t + 1) = (encoding << 24) | (byte_sz * 8); - err = btf_add_type_idx_entry(btf, btf->hdr->type_len); - if (err) - return err; - - btf->hdr->type_len += sz; - btf->hdr->str_off += sz; - btf->nr_types++; - return btf->nr_types; + return btf_commit_type(btf, sz); } /* it's completely legal to append BTF types with type IDs pointing forward to @@ -1631,7 +1768,7 @@ static int validate_type_id(int id) static int btf_add_ref_kind(struct btf *btf, int kind, const char *name, int ref_type_id) { struct btf_type *t; - int sz, name_off = 0, err; + int sz, name_off = 0; if (validate_type_id(ref_type_id)) return -EINVAL; @@ -1654,14 +1791,7 @@ static int btf_add_ref_kind(struct btf *btf, int kind, const char *name, int ref t->info = btf_type_info(kind, 0, 0); t->type = ref_type_id; - err = btf_add_type_idx_entry(btf, btf->hdr->type_len); - if (err) - return err; - - btf->hdr->type_len += sz; - btf->hdr->str_off += sz; - btf->nr_types++; - return btf->nr_types; + return btf_commit_type(btf, sz); } /* @@ -1689,7 +1819,7 @@ int btf__add_array(struct btf *btf, int index_type_id, int elem_type_id, __u32 n { struct btf_type *t; struct btf_array *a; - int sz, err; + int sz; if (validate_type_id(index_type_id) || validate_type_id(elem_type_id)) return -EINVAL; @@ -1711,21 +1841,14 @@ int btf__add_array(struct btf *btf, int index_type_id, int elem_type_id, __u32 n a->index_type = index_type_id; a->nelems = nr_elems; - err = btf_add_type_idx_entry(btf, btf->hdr->type_len); - if (err) - return err; - - btf->hdr->type_len += sz; - btf->hdr->str_off += sz; - btf->nr_types++; - return btf->nr_types; + return btf_commit_type(btf, sz); } /* generic STRUCT/UNION append function */ static int btf_add_composite(struct btf *btf, int kind, const char *name, __u32 bytes_sz) { struct btf_type *t; - int sz, err, name_off = 0; + int sz, name_off = 0; if (btf_ensure_modifiable(btf)) return -ENOMEM; @@ -1748,14 +1871,7 @@ static int btf_add_composite(struct btf *btf, int kind, const char *name, __u32 t->info = btf_type_info(kind, 0, 0); t->size = bytes_sz; - err = btf_add_type_idx_entry(btf, btf->hdr->type_len); - if (err) - return err; - - btf->hdr->type_len += sz; - btf->hdr->str_off += sz; - btf->nr_types++; - return btf->nr_types; + return btf_commit_type(btf, sz); } /* @@ -1793,6 +1909,11 @@ int btf__add_union(struct btf *btf, const char *name, __u32 byte_sz) return btf_add_composite(btf, BTF_KIND_UNION, name, byte_sz); } +static struct btf_type *btf_last_type(struct btf *btf) +{ + return btf_type_by_id(btf, btf__get_nr_types(btf)); +} + /* * Append new field for the current STRUCT/UNION type with: * - *name* - name of the field, can be NULL or empty for anonymous field; @@ -1814,7 +1935,7 @@ int btf__add_field(struct btf *btf, const char *name, int type_id, /* last type should be union/struct */ if (btf->nr_types == 0) return -EINVAL; - t = btf_type_by_id(btf, btf->nr_types); + t = btf_last_type(btf); if (!btf_is_composite(t)) return -EINVAL; @@ -1849,7 +1970,7 @@ int btf__add_field(struct btf *btf, const char *name, int type_id, m->offset = bit_offset | (bit_size << 24); /* btf_add_type_mem can invalidate t pointer */ - t = btf_type_by_id(btf, btf->nr_types); + t = btf_last_type(btf); /* update parent type's vlen and kflag */ t->info = btf_type_info(btf_kind(t), btf_vlen(t) + 1, is_bitfield || btf_kflag(t)); @@ -1874,7 +1995,7 @@ int btf__add_field(struct btf *btf, const char *name, int type_id, int btf__add_enum(struct btf *btf, const char *name, __u32 byte_sz) { struct btf_type *t; - int sz, err, name_off = 0; + int sz, name_off = 0; /* byte_sz must be power of 2 */ if (!byte_sz || (byte_sz & (byte_sz - 1)) || byte_sz > 8) @@ -1899,14 +2020,7 @@ int btf__add_enum(struct btf *btf, const char *name, __u32 byte_sz) t->info = btf_type_info(BTF_KIND_ENUM, 0, 0); t->size = byte_sz; - err = btf_add_type_idx_entry(btf, btf->hdr->type_len); - if (err) - return err; - - btf->hdr->type_len += sz; - btf->hdr->str_off += sz; - btf->nr_types++; - return btf->nr_types; + return btf_commit_type(btf, sz); } /* @@ -1926,7 +2040,7 @@ int btf__add_enum_value(struct btf *btf, const char *name, __s64 value) /* last type should be BTF_KIND_ENUM */ if (btf->nr_types == 0) return -EINVAL; - t = btf_type_by_id(btf, btf->nr_types); + t = btf_last_type(btf); if (!btf_is_enum(t)) return -EINVAL; @@ -1953,7 +2067,7 @@ int btf__add_enum_value(struct btf *btf, const char *name, __s64 value) v->val = value; /* update parent type's vlen */ - t = btf_type_by_id(btf, btf->nr_types); + t = btf_last_type(btf); btf_type_inc_vlen(t); btf->hdr->type_len += sz; @@ -2093,7 +2207,7 @@ int btf__add_func(struct btf *btf, const char *name, int btf__add_func_proto(struct btf *btf, int ret_type_id) { struct btf_type *t; - int sz, err; + int sz; if (validate_type_id(ret_type_id)) return -EINVAL; @@ -2113,14 +2227,7 @@ int btf__add_func_proto(struct btf *btf, int ret_type_id) t->info = btf_type_info(BTF_KIND_FUNC_PROTO, 0, 0); t->type = ret_type_id; - err = btf_add_type_idx_entry(btf, btf->hdr->type_len); - if (err) - return err; - - btf->hdr->type_len += sz; - btf->hdr->str_off += sz; - btf->nr_types++; - return btf->nr_types; + return btf_commit_type(btf, sz); } /* @@ -2143,7 +2250,7 @@ int btf__add_func_param(struct btf *btf, const char *name, int type_id) /* last type should be BTF_KIND_FUNC_PROTO */ if (btf->nr_types == 0) return -EINVAL; - t = btf_type_by_id(btf, btf->nr_types); + t = btf_last_type(btf); if (!btf_is_func_proto(t)) return -EINVAL; @@ -2166,7 +2273,7 @@ int btf__add_func_param(struct btf *btf, const char *name, int type_id) p->type = type_id; /* update parent type's vlen */ - t = btf_type_by_id(btf, btf->nr_types); + t = btf_last_type(btf); btf_type_inc_vlen(t); btf->hdr->type_len += sz; @@ -2188,7 +2295,7 @@ int btf__add_var(struct btf *btf, const char *name, int linkage, int type_id) { struct btf_type *t; struct btf_var *v; - int sz, err, name_off; + int sz, name_off; /* non-empty name */ if (!name || !name[0]) @@ -2219,14 +2326,7 @@ int btf__add_var(struct btf *btf, const char *name, int linkage, int type_id) v = btf_var(t); v->linkage = linkage; - err = btf_add_type_idx_entry(btf, btf->hdr->type_len); - if (err) - return err; - - btf->hdr->type_len += sz; - btf->hdr->str_off += sz; - btf->nr_types++; - return btf->nr_types; + return btf_commit_type(btf, sz); } /* @@ -2244,7 +2344,7 @@ int btf__add_var(struct btf *btf, const char *name, int linkage, int type_id) int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz) { struct btf_type *t; - int sz, err, name_off; + int sz, name_off; /* non-empty name */ if (!name || !name[0]) @@ -2267,14 +2367,7 @@ int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz) t->info = btf_type_info(BTF_KIND_DATASEC, 0, 0); t->size = byte_sz; - err = btf_add_type_idx_entry(btf, btf->hdr->type_len); - if (err) - return err; - - btf->hdr->type_len += sz; - btf->hdr->str_off += sz; - btf->nr_types++; - return btf->nr_types; + return btf_commit_type(btf, sz); } /* @@ -2296,7 +2389,7 @@ int btf__add_datasec_var_info(struct btf *btf, int var_type_id, __u32 offset, __ /* last type should be BTF_KIND_DATASEC */ if (btf->nr_types == 0) return -EINVAL; - t = btf_type_by_id(btf, btf->nr_types); + t = btf_last_type(btf); if (!btf_is_datasec(t)) return -EINVAL; @@ -2317,7 +2410,7 @@ int btf__add_datasec_var_info(struct btf *btf, int var_type_id, __u32 offset, __ v->size = byte_sz; /* update parent type's vlen */ - t = btf_type_by_id(btf, btf->nr_types); + t = btf_last_type(btf); btf_type_inc_vlen(t); btf->hdr->type_len += sz; @@ -2639,6 +2732,7 @@ struct btf_dedup; static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext, const struct btf_dedup_opts *opts); static void btf_dedup_free(struct btf_dedup *d); +static int btf_dedup_prep(struct btf_dedup *d); static int btf_dedup_strings(struct btf_dedup *d); static int btf_dedup_prim_types(struct btf_dedup *d); static int btf_dedup_struct_types(struct btf_dedup *d); @@ -2797,6 +2891,11 @@ int btf__dedup(struct btf *btf, struct btf_ext *btf_ext, if (btf_ensure_modifiable(btf)) return -ENOMEM; + err = btf_dedup_prep(d); + if (err) { + pr_debug("btf_dedup_prep failed:%d\n", err); + goto done; + } err = btf_dedup_strings(d); if (err < 0) { pr_debug("btf_dedup_strings failed:%d\n", err); @@ -2859,21 +2958,20 @@ struct btf_dedup { __u32 *hypot_list; size_t hypot_cnt; size_t hypot_cap; + /* Whether hypothetical mapping, if successful, would need to adjust + * already canonicalized types (due to a new forward declaration to + * concrete type resolution). In such case, during split BTF dedup + * candidate type would still be considered as different, because base + * BTF is considered to be immutable. + */ + bool hypot_adjust_canon; /* Various option modifying behavior of algorithm */ struct btf_dedup_opts opts; -}; - -struct btf_str_ptr { - const char *str; - __u32 new_off; - bool used; -}; - -struct btf_str_ptrs { - struct btf_str_ptr *ptrs; - const char *data; - __u32 cnt; - __u32 cap; + /* temporary strings deduplication state */ + void *strs_data; + size_t strs_cap; + size_t strs_len; + struct hashmap* strs_hash; }; static long hash_combine(long h, long value) @@ -2914,6 +3012,7 @@ static void btf_dedup_clear_hypot_map(struct btf_dedup *d) for (i = 0; i < d->hypot_cnt; i++) d->hypot_map[d->hypot_list[i]] = BTF_UNPROCESSED_ID; d->hypot_cnt = 0; + d->hypot_adjust_canon = false; } static void btf_dedup_free(struct btf_dedup *d) @@ -2953,7 +3052,7 @@ static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext, { struct btf_dedup *d = calloc(1, sizeof(struct btf_dedup)); hashmap_hash_fn hash_fn = btf_dedup_identity_hash_fn; - int i, err = 0; + int i, err = 0, type_cnt; if (!d) return ERR_PTR(-ENOMEM); @@ -2973,14 +3072,15 @@ static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext, goto done; } - d->map = malloc(sizeof(__u32) * (1 + btf->nr_types)); + type_cnt = btf__get_nr_types(btf) + 1; + d->map = malloc(sizeof(__u32) * type_cnt); if (!d->map) { err = -ENOMEM; goto done; } /* special BTF "void" type is made canonical immediately */ d->map[0] = 0; - for (i = 1; i <= btf->nr_types; i++) { + for (i = 1; i < type_cnt; i++) { struct btf_type *t = btf_type_by_id(d->btf, i); /* VAR and DATASEC are never deduped and are self-canonical */ @@ -2990,12 +3090,12 @@ static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext, d->map[i] = BTF_UNPROCESSED_ID; } - d->hypot_map = malloc(sizeof(__u32) * (1 + btf->nr_types)); + d->hypot_map = malloc(sizeof(__u32) * type_cnt); if (!d->hypot_map) { err = -ENOMEM; goto done; } - for (i = 0; i <= btf->nr_types; i++) + for (i = 0; i < type_cnt; i++) d->hypot_map[i] = BTF_UNPROCESSED_ID; done: @@ -3019,8 +3119,8 @@ static int btf_for_each_str_off(struct btf_dedup *d, str_off_fn_t fn, void *ctx) int i, j, r, rec_size; struct btf_type *t; - for (i = 1; i <= d->btf->nr_types; i++) { - t = btf_type_by_id(d->btf, i); + for (i = 0; i < d->btf->nr_types; i++) { + t = btf_type_by_id(d->btf, d->btf->start_id + i); r = fn(&t->name_off, ctx); if (r) return r; @@ -3100,64 +3200,53 @@ static int btf_for_each_str_off(struct btf_dedup *d, str_off_fn_t fn, void *ctx) return 0; } -static int str_sort_by_content(const void *a1, const void *a2) +static int strs_dedup_remap_str_off(__u32 *str_off_ptr, void *ctx) { - const struct btf_str_ptr *p1 = a1; - const struct btf_str_ptr *p2 = a2; - - return strcmp(p1->str, p2->str); -} - -static int str_sort_by_offset(const void *a1, const void *a2) -{ - const struct btf_str_ptr *p1 = a1; - const struct btf_str_ptr *p2 = a2; - - if (p1->str != p2->str) - return p1->str < p2->str ? -1 : 1; - return 0; -} - -static int btf_dedup_str_ptr_cmp(const void *str_ptr, const void *pelem) -{ - const struct btf_str_ptr *p = pelem; - - if (str_ptr != p->str) - return (const char *)str_ptr < p->str ? -1 : 1; - return 0; -} - -static int btf_str_mark_as_used(__u32 *str_off_ptr, void *ctx) -{ - struct btf_str_ptrs *strs; - struct btf_str_ptr *s; + struct btf_dedup *d = ctx; + __u32 str_off = *str_off_ptr; + long old_off, new_off, len; + const char *s; + void *p; + int err; - if (*str_off_ptr == 0) + /* don't touch empty string or string in main BTF */ + if (str_off == 0 || str_off < d->btf->start_str_off) return 0; - strs = ctx; - s = bsearch(strs->data + *str_off_ptr, strs->ptrs, strs->cnt, - sizeof(struct btf_str_ptr), btf_dedup_str_ptr_cmp); - if (!s) - return -EINVAL; - s->used = true; - return 0; -} + s = btf__str_by_offset(d->btf, str_off); + if (d->btf->base_btf) { + err = btf__find_str(d->btf->base_btf, s); + if (err >= 0) { + *str_off_ptr = err; + return 0; + } + if (err != -ENOENT) + return err; + } -static int btf_str_remap_offset(__u32 *str_off_ptr, void *ctx) -{ - struct btf_str_ptrs *strs; - struct btf_str_ptr *s; + len = strlen(s) + 1; - if (*str_off_ptr == 0) - return 0; + new_off = d->strs_len; + p = btf_add_mem(&d->strs_data, &d->strs_cap, 1, new_off, BTF_MAX_STR_OFFSET, len); + if (!p) + return -ENOMEM; - strs = ctx; - s = bsearch(strs->data + *str_off_ptr, strs->ptrs, strs->cnt, - sizeof(struct btf_str_ptr), btf_dedup_str_ptr_cmp); - if (!s) - return -EINVAL; - *str_off_ptr = s->new_off; + memcpy(p, s, len); + + /* Now attempt to add the string, but only if the string with the same + * contents doesn't exist already (HASHMAP_ADD strategy). If such + * string exists, we'll get its offset in old_off (that's old_key). + */ + err = hashmap__insert(d->strs_hash, (void *)new_off, (void *)new_off, + HASHMAP_ADD, (const void **)&old_off, NULL); + if (err == -EEXIST) { + *str_off_ptr = d->btf->start_str_off + old_off; + } else if (err) { + return err; + } else { + *str_off_ptr = d->btf->start_str_off + new_off; + d->strs_len += len; + } return 0; } @@ -3174,118 +3263,71 @@ static int btf_str_remap_offset(__u32 *str_off_ptr, void *ctx) */ static int btf_dedup_strings(struct btf_dedup *d) { - char *start = d->btf->strs_data; - char *end = start + d->btf->hdr->str_len; - char *p = start, *tmp_strs = NULL; - struct btf_str_ptrs strs = { - .cnt = 0, - .cap = 0, - .ptrs = NULL, - .data = start, - }; - int i, j, err = 0, grp_idx; - bool grp_used; + char *s; + int err; if (d->btf->strs_deduped) return 0; - /* build index of all strings */ - while (p < end) { - if (strs.cnt + 1 > strs.cap) { - struct btf_str_ptr *new_ptrs; - - strs.cap += max(strs.cnt / 2, 16U); - new_ptrs = libbpf_reallocarray(strs.ptrs, strs.cap, sizeof(strs.ptrs[0])); - if (!new_ptrs) { - err = -ENOMEM; - goto done; - } - strs.ptrs = new_ptrs; - } - - strs.ptrs[strs.cnt].str = p; - strs.ptrs[strs.cnt].used = false; - - p += strlen(p) + 1; - strs.cnt++; - } + /* temporarily switch to use btf_dedup's strs_data for strings for hash + * functions; later we'll just transfer hashmap to struct btf as is, + * along the strs_data + */ + d->btf->strs_data_ptr = &d->strs_data; - /* temporary storage for deduplicated strings */ - tmp_strs = malloc(d->btf->hdr->str_len); - if (!tmp_strs) { - err = -ENOMEM; - goto done; + d->strs_hash = hashmap__new(strs_hash_fn, strs_hash_equal_fn, d->btf); + if (IS_ERR(d->strs_hash)) { + err = PTR_ERR(d->strs_hash); + d->strs_hash = NULL; + goto err_out; } - /* mark all used strings */ - strs.ptrs[0].used = true; - err = btf_for_each_str_off(d, btf_str_mark_as_used, &strs); - if (err) - goto done; - - /* sort strings by context, so that we can identify duplicates */ - qsort(strs.ptrs, strs.cnt, sizeof(strs.ptrs[0]), str_sort_by_content); - - /* - * iterate groups of equal strings and if any instance in a group was - * referenced, emit single instance and remember new offset - */ - p = tmp_strs; - grp_idx = 0; - grp_used = strs.ptrs[0].used; - /* iterate past end to avoid code duplication after loop */ - for (i = 1; i <= strs.cnt; i++) { - /* - * when i == strs.cnt, we want to skip string comparison and go - * straight to handling last group of strings (otherwise we'd - * need to handle last group after the loop w/ duplicated code) - */ - if (i < strs.cnt && - !strcmp(strs.ptrs[i].str, strs.ptrs[grp_idx].str)) { - grp_used = grp_used || strs.ptrs[i].used; - continue; - } + if (!d->btf->base_btf) { + s = btf_add_mem(&d->strs_data, &d->strs_cap, 1, d->strs_len, BTF_MAX_STR_OFFSET, 1); + if (!s) + return -ENOMEM; + /* initial empty string */ + s[0] = 0; + d->strs_len = 1; - /* - * this check would have been required after the loop to handle - * last group of strings, but due to <= condition in a loop - * we avoid that duplication + /* insert empty string; we won't be looking it up during strings + * dedup, but it's good to have it for generic BTF string lookups */ - if (grp_used) { - int new_off = p - tmp_strs; - __u32 len = strlen(strs.ptrs[grp_idx].str); - - memmove(p, strs.ptrs[grp_idx].str, len + 1); - for (j = grp_idx; j < i; j++) - strs.ptrs[j].new_off = new_off; - p += len + 1; - } - - if (i < strs.cnt) { - grp_idx = i; - grp_used = strs.ptrs[i].used; - } + err = hashmap__insert(d->strs_hash, (void *)0, (void *)0, + HASHMAP_ADD, NULL, NULL); + if (err) + goto err_out; } - /* replace original strings with deduped ones */ - d->btf->hdr->str_len = p - tmp_strs; - memmove(start, tmp_strs, d->btf->hdr->str_len); - end = start + d->btf->hdr->str_len; - - /* restore original order for further binary search lookups */ - qsort(strs.ptrs, strs.cnt, sizeof(strs.ptrs[0]), str_sort_by_offset); - /* remap string offsets */ - err = btf_for_each_str_off(d, btf_str_remap_offset, &strs); + err = btf_for_each_str_off(d, strs_dedup_remap_str_off, d); if (err) - goto done; + goto err_out; - d->btf->hdr->str_len = end - start; + /* replace BTF string data and hash with deduped ones */ + free(d->btf->strs_data); + hashmap__free(d->btf->strs_hash); + d->btf->strs_data = d->strs_data; + d->btf->strs_data_cap = d->strs_cap; + d->btf->hdr->str_len = d->strs_len; + d->btf->strs_hash = d->strs_hash; + /* now point strs_data_ptr back to btf->strs_data */ + d->btf->strs_data_ptr = &d->btf->strs_data; + + d->strs_data = d->strs_hash = NULL; + d->strs_len = d->strs_cap = 0; d->btf->strs_deduped = true; + return 0; + +err_out: + free(d->strs_data); + hashmap__free(d->strs_hash); + d->strs_data = d->strs_hash = NULL; + d->strs_len = d->strs_cap = 0; + + /* restore strings pointer for existing d->btf->strs_hash back */ + d->btf->strs_data_ptr = &d->strs_data; -done: - free(tmp_strs); - free(strs.ptrs); return err; } @@ -3550,6 +3592,66 @@ static bool btf_compat_fnproto(struct btf_type *t1, struct btf_type *t2) return true; } +/* Prepare split BTF for deduplication by calculating hashes of base BTF's + * types and initializing the rest of the state (canonical type mapping) for + * the fixed base BTF part. + */ +static int btf_dedup_prep(struct btf_dedup *d) +{ + struct btf_type *t; + int type_id; + long h; + + if (!d->btf->base_btf) + return 0; + + for (type_id = 1; type_id < d->btf->start_id; type_id++) { + t = btf_type_by_id(d->btf, type_id); + + /* all base BTF types are self-canonical by definition */ + d->map[type_id] = type_id; + + switch (btf_kind(t)) { + case BTF_KIND_VAR: + case BTF_KIND_DATASEC: + /* VAR and DATASEC are never hash/deduplicated */ + continue; + case BTF_KIND_CONST: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_PTR: + case BTF_KIND_FWD: + case BTF_KIND_TYPEDEF: + case BTF_KIND_FUNC: + h = btf_hash_common(t); + break; + case BTF_KIND_INT: + h = btf_hash_int(t); + break; + case BTF_KIND_ENUM: + h = btf_hash_enum(t); + break; + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + h = btf_hash_struct(t); + break; + case BTF_KIND_ARRAY: + h = btf_hash_array(t); + break; + case BTF_KIND_FUNC_PROTO: + h = btf_hash_fnproto(t); + break; + default: + pr_debug("unknown kind %d for type [%d]\n", btf_kind(t), type_id); + return -EINVAL; + } + if (btf_dedup_table_add(d, h, type_id)) + return -ENOMEM; + } + + return 0; +} + /* * Deduplicate primitive types, that can't reference other types, by calculating * their type signature hash and comparing them with any possible canonical @@ -3643,8 +3745,8 @@ static int btf_dedup_prim_types(struct btf_dedup *d) { int i, err; - for (i = 1; i <= d->btf->nr_types; i++) { - err = btf_dedup_prim_type(d, i); + for (i = 0; i < d->btf->nr_types; i++) { + err = btf_dedup_prim_type(d, d->btf->start_id + i); if (err) return err; } @@ -3697,6 +3799,19 @@ static inline __u16 btf_fwd_kind(struct btf_type *t) return btf_kflag(t) ? BTF_KIND_UNION : BTF_KIND_STRUCT; } +/* Check if given two types are identical ARRAY definitions */ +static int btf_dedup_identical_arrays(struct btf_dedup *d, __u32 id1, __u32 id2) +{ + struct btf_type *t1, *t2; + + t1 = btf_type_by_id(d->btf, id1); + t2 = btf_type_by_id(d->btf, id2); + if (!btf_is_array(t1) || !btf_is_array(t2)) + return 0; + + return btf_equal_array(t1, t2); +} + /* * Check equivalence of BTF type graph formed by candidate struct/union (we'll * call it "candidate graph" in this description for brevity) to a type graph @@ -3807,8 +3922,18 @@ 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_NR_TYPES) - return hypot_type_id == cand_id; + if (hypot_type_id <= BTF_MAX_NR_TYPES) { + /* In some cases compiler will generate different DWARF types + * for *identical* array type definitions and use them for + * different fields within the *same* struct. This breaks type + * equivalence check, which makes an assumption that candidate + * types sub-graph has a consistent and deduped-by-compiler + * types within a single CU. So work around that by explicitly + * allowing identical array types here. + */ + return hypot_type_id == cand_id || + btf_dedup_identical_arrays(d, hypot_type_id, cand_id); + } if (btf_dedup_hypot_map_add(d, canon_id, cand_id)) return -ENOMEM; @@ -3834,6 +3959,9 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id, } else { real_kind = cand_kind; fwd_kind = btf_fwd_kind(canon_type); + /* we'd need to resolve base FWD to STRUCT/UNION */ + if (fwd_kind == real_kind && canon_id < d->btf->start_id) + d->hypot_adjust_canon = true; } return fwd_kind == real_kind; } @@ -3871,8 +3999,7 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id, return 0; cand_arr = btf_array(cand_type); canon_arr = btf_array(canon_type); - eq = btf_dedup_is_equiv(d, - cand_arr->index_type, canon_arr->index_type); + eq = btf_dedup_is_equiv(d, cand_arr->index_type, canon_arr->index_type); if (eq <= 0) return eq; return btf_dedup_is_equiv(d, cand_arr->type, canon_arr->type); @@ -3955,16 +4082,16 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id, */ static void btf_dedup_merge_hypot_map(struct btf_dedup *d) { - __u32 cand_type_id, targ_type_id; + __u32 canon_type_id, targ_type_id; __u16 t_kind, c_kind; __u32 t_id, c_id; int i; for (i = 0; i < d->hypot_cnt; i++) { - cand_type_id = d->hypot_list[i]; - targ_type_id = d->hypot_map[cand_type_id]; + canon_type_id = d->hypot_list[i]; + targ_type_id = d->hypot_map[canon_type_id]; t_id = resolve_type_id(d, targ_type_id); - c_id = resolve_type_id(d, cand_type_id); + c_id = resolve_type_id(d, canon_type_id); t_kind = btf_kind(btf__type_by_id(d->btf, t_id)); c_kind = btf_kind(btf__type_by_id(d->btf, c_id)); /* @@ -3979,9 +4106,26 @@ static void btf_dedup_merge_hypot_map(struct btf_dedup *d) * stability is not a requirement for STRUCT/UNION equivalence * checks, though. */ + + /* if it's the split BTF case, we still need to point base FWD + * to STRUCT/UNION in a split BTF, because FWDs from split BTF + * will be resolved against base FWD. If we don't point base + * canonical FWD to the resolved STRUCT/UNION, then all the + * FWDs in split BTF won't be correctly resolved to a proper + * STRUCT/UNION. + */ if (t_kind != BTF_KIND_FWD && c_kind == BTF_KIND_FWD) d->map[c_id] = t_id; - else if (t_kind == BTF_KIND_FWD && c_kind != BTF_KIND_FWD) + + /* if graph equivalence determined that we'd need to adjust + * base canonical types, then we need to only point base FWDs + * to STRUCTs/UNIONs and do no more modifications. For all + * other purposes the type graphs were not equivalent. + */ + if (d->hypot_adjust_canon) + continue; + + if (t_kind == BTF_KIND_FWD && c_kind != BTF_KIND_FWD) d->map[t_id] = c_id; if ((t_kind == BTF_KIND_STRUCT || t_kind == BTF_KIND_UNION) && @@ -4065,8 +4209,10 @@ static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id) return eq; if (!eq) continue; - new_id = cand_id; btf_dedup_merge_hypot_map(d); + if (d->hypot_adjust_canon) /* not really equivalent */ + continue; + new_id = cand_id; break; } @@ -4081,8 +4227,8 @@ static int btf_dedup_struct_types(struct btf_dedup *d) { int i, err; - for (i = 1; i <= d->btf->nr_types; i++) { - err = btf_dedup_struct_type(d, i); + for (i = 0; i < d->btf->nr_types; i++) { + err = btf_dedup_struct_type(d, d->btf->start_id + i); if (err) return err; } @@ -4225,8 +4371,8 @@ static int btf_dedup_ref_types(struct btf_dedup *d) { int i, err; - for (i = 1; i <= d->btf->nr_types; i++) { - err = btf_dedup_ref_type(d, i); + for (i = 0; i < d->btf->nr_types; i++) { + err = btf_dedup_ref_type(d, d->btf->start_id + i); if (err < 0) return err; } @@ -4250,39 +4396,44 @@ static int btf_dedup_ref_types(struct btf_dedup *d) static int btf_dedup_compact_types(struct btf_dedup *d) { __u32 *new_offs; - __u32 next_type_id = 1; + __u32 next_type_id = d->btf->start_id; + const struct btf_type *t; void *p; - int i, len; + int i, id, len; /* we are going to reuse hypot_map to store compaction remapping */ d->hypot_map[0] = 0; - for (i = 1; i <= d->btf->nr_types; i++) - d->hypot_map[i] = BTF_UNPROCESSED_ID; + /* base BTF types are not renumbered */ + for (id = 1; id < d->btf->start_id; id++) + d->hypot_map[id] = id; + for (i = 0, id = d->btf->start_id; i < d->btf->nr_types; i++, id++) + d->hypot_map[id] = BTF_UNPROCESSED_ID; p = d->btf->types_data; - for (i = 1; i <= d->btf->nr_types; i++) { - if (d->map[i] != i) + for (i = 0, id = d->btf->start_id; i < d->btf->nr_types; i++, id++) { + if (d->map[id] != id) continue; - len = btf_type_size(btf__type_by_id(d->btf, i)); + t = btf__type_by_id(d->btf, id); + len = btf_type_size(t); if (len < 0) return len; - memmove(p, btf__type_by_id(d->btf, i), len); - d->hypot_map[i] = next_type_id; - d->btf->type_offs[next_type_id] = p - d->btf->types_data; + memmove(p, t, len); + d->hypot_map[id] = next_type_id; + d->btf->type_offs[next_type_id - d->btf->start_id] = p - d->btf->types_data; p += len; next_type_id++; } /* shrink struct btf's internal types index and update btf_header */ - d->btf->nr_types = next_type_id - 1; - d->btf->type_offs_cap = d->btf->nr_types + 1; + d->btf->nr_types = next_type_id - d->btf->start_id; + d->btf->type_offs_cap = d->btf->nr_types; d->btf->hdr->type_len = p - d->btf->types_data; new_offs = libbpf_reallocarray(d->btf->type_offs, d->btf->type_offs_cap, sizeof(*new_offs)); - if (!new_offs) + if (d->btf->type_offs_cap && !new_offs) return -ENOMEM; d->btf->type_offs = new_offs; d->btf->hdr->str_off = d->btf->hdr->type_len; @@ -4414,8 +4565,8 @@ static int btf_dedup_remap_types(struct btf_dedup *d) { int i, r; - for (i = 1; i <= d->btf->nr_types; i++) { - r = btf_dedup_remap_type(d, i); + for (i = 0; i < d->btf->nr_types; i++) { + r = btf_dedup_remap_type(d, d->btf->start_id + i); if (r < 0) return r; } |