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-rw-r--r--tools/lib/bpf/btf.c221
1 files changed, 168 insertions, 53 deletions
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 20bb88e71f07..8d04d9becb67 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -2718,6 +2718,7 @@ 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);
@@ -2876,6 +2877,11 @@ 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);
@@ -2938,6 +2944,13 @@ 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;
/* temporary strings deduplication state */
@@ -2985,6 +2998,7 @@ 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)
@@ -3024,7 +3038,7 @@ 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);
@@ -3044,14 +3058,15 @@ 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 */
@@ -3061,12 +3076,12 @@ 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:
@@ -3090,8 +3105,8 @@ 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;
@@ -3174,15 +3189,27 @@ static int btf_for_each_str_off(struct btf_dedup *d, str_off_fn_t fn, void *ctx)
static int strs_dedup_remap_str_off(__u32 *str_off_ptr, void *ctx)
{
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;
- s = btf__str_by_offset(d->btf, *str_off_ptr);
+ 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;
+ }
+
len = strlen(s) + 1;
new_off = d->strs_len;
@@ -3199,11 +3226,11 @@ static int strs_dedup_remap_str_off(__u32 *str_off_ptr, void *ctx)
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 = old_off;
+ *str_off_ptr = d->btf->start_str_off + old_off;
} else if (err) {
return err;
} else {
- *str_off_ptr = new_off;
+ *str_off_ptr = d->btf->start_str_off + new_off;
d->strs_len += len;
}
return 0;
@@ -3228,13 +3255,6 @@ static int btf_dedup_strings(struct btf_dedup *d)
if (d->btf->strs_deduped)
return 0;
- 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;
-
/* 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
@@ -3248,13 +3268,22 @@ static int btf_dedup_strings(struct btf_dedup *d)
goto err_out;
}
- /* 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
- */
- err = hashmap__insert(d->strs_hash, (void *)0, (void *)0,
- HASHMAP_ADD, NULL, NULL);
- if (err)
- goto err_out;
+ 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;
+
+ /* 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
+ */
+ err = hashmap__insert(d->strs_hash, (void *)0, (void *)0,
+ HASHMAP_ADD, NULL, NULL);
+ if (err)
+ goto err_out;
+ }
/* remap string offsets */
err = btf_for_each_str_off(d, strs_dedup_remap_str_off, d);
@@ -3549,6 +3578,66 @@ 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
@@ -3642,8 +3731,8 @@ 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;
}
@@ -3833,6 +3922,9 @@ 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;
}
@@ -3870,8 +3962,7 @@ 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);
@@ -3954,16 +4045,16 @@ 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));
/*
@@ -3978,9 +4069,26 @@ 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) &&
@@ -4064,8 +4172,10 @@ 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;
}
@@ -4080,8 +4190,8 @@ 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;
}
@@ -4224,8 +4334,8 @@ 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;
}
@@ -4249,39 +4359,44 @@ 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 - 1] = 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->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;
@@ -4413,8 +4528,8 @@ 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;
}
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-15 18:06:29 +0300