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Diffstat (limited to 'tools/lib/bpf/btf.c')
-rw-r--r--tools/lib/bpf/btf.c76
1 files changed, 55 insertions, 21 deletions
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 68b50e9bbde1..1b8d8cdd3575 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -1070,8 +1070,8 @@ done:
return err;
}
-#define BTF_DEDUP_TABLE_SIZE_LOG 14
-#define BTF_DEDUP_TABLE_MOD ((1 << BTF_DEDUP_TABLE_SIZE_LOG) - 1)
+#define BTF_DEDUP_TABLE_DEFAULT_SIZE (1 << 14)
+#define BTF_DEDUP_TABLE_MAX_SIZE_LOG 31
#define BTF_UNPROCESSED_ID ((__u32)-1)
#define BTF_IN_PROGRESS_ID ((__u32)-2)
@@ -1128,18 +1128,21 @@ static inline __u32 hash_combine(__u32 h, __u32 value)
#undef GOLDEN_RATIO_PRIME
}
-#define for_each_hash_node(table, hash, node) \
- for (node = table[hash & BTF_DEDUP_TABLE_MOD]; node; node = node->next)
+#define for_each_dedup_cand(d, hash, node) \
+ for (node = d->dedup_table[hash & (d->opts.dedup_table_size - 1)]; \
+ node; \
+ node = node->next)
static int btf_dedup_table_add(struct btf_dedup *d, __u32 hash, __u32 type_id)
{
struct btf_dedup_node *node = malloc(sizeof(struct btf_dedup_node));
+ int bucket = hash & (d->opts.dedup_table_size - 1);
if (!node)
return -ENOMEM;
node->type_id = type_id;
- node->next = d->dedup_table[hash & BTF_DEDUP_TABLE_MOD];
- d->dedup_table[hash & BTF_DEDUP_TABLE_MOD] = node;
+ node->next = d->dedup_table[bucket];
+ d->dedup_table[bucket] = node;
return 0;
}
@@ -1177,7 +1180,7 @@ static void btf_dedup_table_free(struct btf_dedup *d)
if (!d->dedup_table)
return;
- for (i = 0; i < (1 << BTF_DEDUP_TABLE_SIZE_LOG); i++) {
+ for (i = 0; i < d->opts.dedup_table_size; i++) {
while (d->dedup_table[i]) {
tmp = d->dedup_table[i];
d->dedup_table[i] = tmp->next;
@@ -1212,19 +1215,37 @@ static void btf_dedup_free(struct btf_dedup *d)
free(d);
}
+/* Find closest power of two >= to size, capped at 2^max_size_log */
+static __u32 roundup_pow2_max(__u32 size, int max_size_log)
+{
+ int i;
+
+ for (i = 0; i < max_size_log && (1U << i) < size; i++)
+ ;
+ return 1U << i;
+}
+
+
static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext,
const struct btf_dedup_opts *opts)
{
struct btf_dedup *d = calloc(1, sizeof(struct btf_dedup));
int i, err = 0;
+ __u32 sz;
if (!d)
return ERR_PTR(-ENOMEM);
+ d->opts.dont_resolve_fwds = opts && opts->dont_resolve_fwds;
+ sz = opts && opts->dedup_table_size ? opts->dedup_table_size
+ : BTF_DEDUP_TABLE_DEFAULT_SIZE;
+ sz = roundup_pow2_max(sz, BTF_DEDUP_TABLE_MAX_SIZE_LOG);
+ d->opts.dedup_table_size = sz;
+
d->btf = btf;
d->btf_ext = btf_ext;
- d->dedup_table = calloc(1 << BTF_DEDUP_TABLE_SIZE_LOG,
+ d->dedup_table = calloc(d->opts.dedup_table_size,
sizeof(struct btf_dedup_node *));
if (!d->dedup_table) {
err = -ENOMEM;
@@ -1249,8 +1270,6 @@ static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext,
for (i = 0; i <= btf->nr_types; i++)
d->hypot_map[i] = BTF_UNPROCESSED_ID;
- d->opts.dont_resolve_fwds = opts && opts->dont_resolve_fwds;
-
done:
if (err) {
btf_dedup_free(d);
@@ -1644,7 +1663,7 @@ static __u32 btf_hash_struct(struct btf_type *t)
* IDs. This check is performed during type graph equivalence check and
* referenced types equivalence is checked separately.
*/
-static bool btf_equal_struct(struct btf_type *t1, struct btf_type *t2)
+static bool btf_shallow_equal_struct(struct btf_type *t1, struct btf_type *t2)
{
struct btf_member *m1, *m2;
__u16 vlen;
@@ -1824,7 +1843,7 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id)
case BTF_KIND_INT:
h = btf_hash_int(t);
- for_each_hash_node(d->dedup_table, h, cand_node) {
+ for_each_dedup_cand(d, h, cand_node) {
cand = d->btf->types[cand_node->type_id];
if (btf_equal_int(t, cand)) {
new_id = cand_node->type_id;
@@ -1835,7 +1854,7 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id)
case BTF_KIND_ENUM:
h = btf_hash_enum(t);
- for_each_hash_node(d->dedup_table, h, cand_node) {
+ for_each_dedup_cand(d, h, cand_node) {
cand = d->btf->types[cand_node->type_id];
if (btf_equal_enum(t, cand)) {
new_id = cand_node->type_id;
@@ -1846,7 +1865,7 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id)
case BTF_KIND_FWD:
h = btf_hash_common(t);
- for_each_hash_node(d->dedup_table, h, cand_node) {
+ for_each_dedup_cand(d, h, cand_node) {
cand = d->btf->types[cand_node->type_id];
if (btf_equal_common(t, cand)) {
new_id = cand_node->type_id;
@@ -2105,7 +2124,7 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id,
struct btf_member *cand_m, *canon_m;
__u16 vlen;
- if (!btf_equal_struct(cand_type, canon_type))
+ if (!btf_shallow_equal_struct(cand_type, canon_type))
return 0;
vlen = BTF_INFO_VLEN(cand_type->info);
cand_m = (struct btf_member *)(cand_type + 1);
@@ -2246,7 +2265,7 @@ static void btf_dedup_merge_hypot_map(struct btf_dedup *d)
static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id)
{
struct btf_dedup_node *cand_node;
- struct btf_type *t;
+ struct btf_type *cand_type, *t;
/* if we don't find equivalent type, then we are canonical */
__u32 new_id = type_id;
__u16 kind;
@@ -2263,9 +2282,23 @@ static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id)
return 0;
h = btf_hash_struct(t);
- for_each_hash_node(d->dedup_table, h, cand_node) {
+ for_each_dedup_cand(d, h, cand_node) {
int eq;
+ /*
+ * Even though btf_dedup_is_equiv() checks for
+ * btf_shallow_equal_struct() internally when checking two
+ * structs (unions) for equivalence, we need to guard here
+ * from picking matching FWD type as a dedup candidate.
+ * This can happen due to hash collision. In such case just
+ * relying on btf_dedup_is_equiv() would lead to potentially
+ * creating a loop (FWD -> STRUCT and STRUCT -> FWD), because
+ * FWD and compatible STRUCT/UNION are considered equivalent.
+ */
+ cand_type = d->btf->types[cand_node->type_id];
+ if (!btf_shallow_equal_struct(t, cand_type))
+ continue;
+
btf_dedup_clear_hypot_map(d);
eq = btf_dedup_is_equiv(d, type_id, cand_node->type_id);
if (eq < 0)
@@ -2326,7 +2359,8 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id)
struct btf_type *t, *cand;
/* if we don't find equivalent type, then we are representative type */
__u32 new_id = type_id;
- __u32 h, ref_type_id;
+ int ref_type_id;
+ __u32 h;
if (d->map[type_id] == BTF_IN_PROGRESS_ID)
return -ELOOP;
@@ -2349,7 +2383,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id)
t->type = ref_type_id;
h = btf_hash_common(t);
- for_each_hash_node(d->dedup_table, h, cand_node) {
+ for_each_dedup_cand(d, h, cand_node) {
cand = d->btf->types[cand_node->type_id];
if (btf_equal_common(t, cand)) {
new_id = cand_node->type_id;
@@ -2372,7 +2406,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id)
info->index_type = ref_type_id;
h = btf_hash_array(t);
- for_each_hash_node(d->dedup_table, h, cand_node) {
+ for_each_dedup_cand(d, h, cand_node) {
cand = d->btf->types[cand_node->type_id];
if (btf_equal_array(t, cand)) {
new_id = cand_node->type_id;
@@ -2403,7 +2437,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id)
}
h = btf_hash_fnproto(t);
- for_each_hash_node(d->dedup_table, h, cand_node) {
+ for_each_dedup_cand(d, h, cand_node) {
cand = d->btf->types[cand_node->type_id];
if (btf_equal_fnproto(t, cand)) {
new_id = cand_node->type_id;
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-21 07:14:23 +0300