Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Andrii Nakryiko says:

====================
bpf-next 2022-11-11

We've added 49 non-merge commits during the last 9 day(s) which contain
a total of 68 files changed, 3592 insertions(+), 1371 deletions(-).

The main changes are:

1) Veristat tool improvements to support custom filtering, sorting, and replay
   of results, from Andrii Nakryiko.

2) BPF verifier precision tracking fixes and improvements,
   from Andrii Nakryiko.

3) Lots of new BPF documentation for various BPF maps, from Dave Tucker,
   Donald Hunter, Maryam Tahhan, Bagas Sanjaya.

4) BTF dedup improvements and libbpf's hashmap interface clean ups, from
   Eduard Zingerman.

5) Fix veth driver panic if XDP program is attached before veth_open, from
   John Fastabend.

6) BPF verifier clean ups and fixes in preparation for follow up features,
   from Kumar Kartikeya Dwivedi.

7) Add access to hwtstamp field from BPF sockops programs,
   from Martin KaFai Lau.

8) Various fixes for BPF selftests and samples, from Artem Savkov,
   Domenico Cerasuolo, Kang Minchul, Rong Tao, Yang Jihong.

9) Fix redirection to tunneling device logic, preventing skb->len == 0, from
   Stanislav Fomichev.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (49 commits)
  selftests/bpf: fix veristat's singular file-or-prog filter
  selftests/bpf: Test skops->skb_hwtstamp
  selftests/bpf: Fix incorrect ASSERT in the tcp_hdr_options test
  bpf: Add hwtstamp field for the sockops prog
  selftests/bpf: Fix xdp_synproxy compilation failure in 32-bit arch
  bpf, docs: Document BPF_MAP_TYPE_ARRAY
  docs/bpf: Document BPF map types QUEUE and STACK
  docs/bpf: Document BPF ARRAY_OF_MAPS and HASH_OF_MAPS
  docs/bpf: Document BPF_MAP_TYPE_CPUMAP map
  docs/bpf: Document BPF_MAP_TYPE_LPM_TRIE map
  libbpf: Hashmap.h update to fix build issues using LLVM14
  bpf: veth driver panics when xdp prog attached before veth_open
  selftests: Fix test group SKIPPED result
  selftests/bpf: Tests for btf_dedup_resolve_fwds
  libbpf: Resolve unambigous forward declarations
  libbpf: Hashmap interface update to allow both long and void* keys/values
  samples/bpf: Fix sockex3 error: Missing BPF prog type
  selftests/bpf: Fix u32 variable compared with less than zero
  Documentation: bpf: Escape underscore in BPF type name prefix
  selftests/bpf: Use consistent build-id type for liburandom_read.so
  ...
====================

Link: https://lore.kernel.org/r/20221111233733.1088228-1-andrii@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

7 files changed, 284 insertions, 163 deletions

diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 675a0df5c840..3bd812bf88ff 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -1559,15 +1559,15 @@ struct btf_pipe {
 static int btf_rewrite_str(__u32 *str_off, void *ctx)
 {
 	struct btf_pipe *p = ctx;
-	void *mapped_off;
+	long mapped_off;
 	int off, err;
 
 	if (!*str_off) /* nothing to do for empty strings */
 		return 0;
 
 	if (p->str_off_map &&
-	    hashmap__find(p->str_off_map, (void *)(long)*str_off, &mapped_off)) {
-		*str_off = (__u32)(long)mapped_off;
+	    hashmap__find(p->str_off_map, *str_off, &mapped_off)) {
+		*str_off = mapped_off;
 		return 0;
 	}
 
@@ -1579,7 +1579,7 @@ static int btf_rewrite_str(__u32 *str_off, void *ctx)
 	 * performing expensive string comparisons.
 	 */
 	if (p->str_off_map) {
-		err = hashmap__append(p->str_off_map, (void *)(long)*str_off, (void *)(long)off);
+		err = hashmap__append(p->str_off_map, *str_off, off);
 		if (err)
 			return err;
 	}
@@ -1630,8 +1630,8 @@ static int btf_rewrite_type_ids(__u32 *type_id, void *ctx)
 	return 0;
 }
 
-static size_t btf_dedup_identity_hash_fn(const void *key, void *ctx);
-static bool btf_dedup_equal_fn(const void *k1, const void *k2, void *ctx);
+static size_t btf_dedup_identity_hash_fn(long key, void *ctx);
+static bool btf_dedup_equal_fn(long k1, long k2, void *ctx);
 
 int btf__add_btf(struct btf *btf, const struct btf *src_btf)
 {
@@ -2881,6 +2881,7 @@ 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);
 static int btf_dedup_ref_types(struct btf_dedup *d);
+static int btf_dedup_resolve_fwds(struct btf_dedup *d);
 static int btf_dedup_compact_types(struct btf_dedup *d);
 static int btf_dedup_remap_types(struct btf_dedup *d);
 
@@ -2988,15 +2989,16 @@ static int btf_dedup_remap_types(struct btf_dedup *d);
  * Algorithm summary
  * =================
  *
- * Algorithm completes its work in 6 separate passes:
+ * Algorithm completes its work in 7 separate passes:
  *
  * 1. Strings deduplication.
  * 2. Primitive types deduplication (int, enum, fwd).
  * 3. Struct/union types deduplication.
- * 4. Reference types deduplication (pointers, typedefs, arrays, funcs, func
+ * 4. Resolve unambiguous forward declarations.
+ * 5. Reference types deduplication (pointers, typedefs, arrays, funcs, func
  *    protos, and const/volatile/restrict modifiers).
- * 5. Types compaction.
- * 6. Types remapping.
+ * 6. Types compaction.
+ * 7. Types remapping.
  *
  * Algorithm determines canonical type descriptor, which is a single
  * representative type for each truly unique type. This canonical type is the
@@ -3060,6 +3062,11 @@ int btf__dedup(struct btf *btf, const struct btf_dedup_opts *opts)
 		pr_debug("btf_dedup_struct_types failed:%d\n", err);
 		goto done;
 	}
+	err = btf_dedup_resolve_fwds(d);
+	if (err < 0) {
+		pr_debug("btf_dedup_resolve_fwds failed:%d\n", err);
+		goto done;
+	}
 	err = btf_dedup_ref_types(d);
 	if (err < 0) {
 		pr_debug("btf_dedup_ref_types failed:%d\n", err);
@@ -3126,12 +3133,11 @@ static long hash_combine(long h, long value)
 }
 
 #define for_each_dedup_cand(d, node, hash) \
-	hashmap__for_each_key_entry(d->dedup_table, node, (void *)hash)
+	hashmap__for_each_key_entry(d->dedup_table, node, hash)
 
 static int btf_dedup_table_add(struct btf_dedup *d, long hash, __u32 type_id)
 {
-	return hashmap__append(d->dedup_table,
-			       (void *)hash, (void *)(long)type_id);
+	return hashmap__append(d->dedup_table, hash, type_id);
 }
 
 static int btf_dedup_hypot_map_add(struct btf_dedup *d,
@@ -3178,17 +3184,17 @@ static void btf_dedup_free(struct btf_dedup *d)
 	free(d);
 }
 
-static size_t btf_dedup_identity_hash_fn(const void *key, void *ctx)
+static size_t btf_dedup_identity_hash_fn(long key, void *ctx)
 {
-	return (size_t)key;
+	return key;
 }
 
-static size_t btf_dedup_collision_hash_fn(const void *key, void *ctx)
+static size_t btf_dedup_collision_hash_fn(long key, void *ctx)
 {
 	return 0;
 }
 
-static bool btf_dedup_equal_fn(const void *k1, const void *k2, void *ctx)
+static bool btf_dedup_equal_fn(long k1, long k2, void *ctx)
 {
 	return k1 == k2;
 }
@@ -3404,23 +3410,17 @@ static long btf_hash_enum(struct btf_type *t)
 {
 	long h;
 
-	/* don't hash vlen and enum members to support enum fwd resolving */
+	/* don't hash vlen, enum members and size to support enum fwd resolving */
 	h = hash_combine(0, t->name_off);
-	h = hash_combine(h, t->info & ~0xffff);
-	h = hash_combine(h, t->size);
 	return h;
 }
 
-/* Check structural equality of two ENUMs. */
-static bool btf_equal_enum(struct btf_type *t1, struct btf_type *t2)
+static bool btf_equal_enum_members(struct btf_type *t1, struct btf_type *t2)
 {
 	const struct btf_enum *m1, *m2;
 	__u16 vlen;
 	int i;
 
-	if (!btf_equal_common(t1, t2))
-		return false;
-
 	vlen = btf_vlen(t1);
 	m1 = btf_enum(t1);
 	m2 = btf_enum(t2);
@@ -3433,15 +3433,12 @@ static bool btf_equal_enum(struct btf_type *t1, struct btf_type *t2)
 	return true;
 }
 
-static bool btf_equal_enum64(struct btf_type *t1, struct btf_type *t2)
+static bool btf_equal_enum64_members(struct btf_type *t1, struct btf_type *t2)
 {
 	const struct btf_enum64 *m1, *m2;
 	__u16 vlen;
 	int i;
 
-	if (!btf_equal_common(t1, t2))
-		return false;
-
 	vlen = btf_vlen(t1);
 	m1 = btf_enum64(t1);
 	m2 = btf_enum64(t2);
@@ -3455,6 +3452,19 @@ static bool btf_equal_enum64(struct btf_type *t1, struct btf_type *t2)
 	return true;
 }
 
+/* Check structural equality of two ENUMs or ENUM64s. */
+static bool btf_equal_enum(struct btf_type *t1, struct btf_type *t2)
+{
+	if (!btf_equal_common(t1, t2))
+		return false;
+
+	/* t1 & t2 kinds are identical because of btf_equal_common */
+	if (btf_kind(t1) == BTF_KIND_ENUM)
+		return btf_equal_enum_members(t1, t2);
+	else
+		return btf_equal_enum64_members(t1, t2);
+}
+
 static inline bool btf_is_enum_fwd(struct btf_type *t)
 {
 	return btf_is_any_enum(t) && btf_vlen(t) == 0;
@@ -3464,21 +3474,14 @@ static bool btf_compat_enum(struct btf_type *t1, struct btf_type *t2)
 {
 	if (!btf_is_enum_fwd(t1) && !btf_is_enum_fwd(t2))
 		return btf_equal_enum(t1, t2);
-	/* ignore vlen when comparing */
-	return t1->name_off == t2->name_off &&
-	       (t1->info & ~0xffff) == (t2->info & ~0xffff) &&
-	       t1->size == t2->size;
-}
-
-static bool btf_compat_enum64(struct btf_type *t1, struct btf_type *t2)
-{
-	if (!btf_is_enum_fwd(t1) && !btf_is_enum_fwd(t2))
-		return btf_equal_enum64(t1, t2);
-
-	/* ignore vlen when comparing */
+	/* At this point either t1 or t2 or both are forward declarations, thus:
+	 * - skip comparing vlen because it is zero for forward declarations;
+	 * - skip comparing size to allow enum forward declarations
+	 *   to be compatible with enum64 full declarations;
+	 * - skip comparing kind for the same reason.
+	 */
 	return t1->name_off == t2->name_off &&
-	       (t1->info & ~0xffff) == (t2->info & ~0xffff) &&
-	       t1->size == t2->size;
+	       btf_is_any_enum(t1) && btf_is_any_enum(t2);
 }
 
 /*
@@ -3753,7 +3756,7 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id)
 	case BTF_KIND_INT:
 		h = btf_hash_int_decl_tag(t);
 		for_each_dedup_cand(d, hash_entry, h) {
-			cand_id = (__u32)(long)hash_entry->value;
+			cand_id = hash_entry->value;
 			cand = btf_type_by_id(d->btf, cand_id);
 			if (btf_equal_int_tag(t, cand)) {
 				new_id = cand_id;
@@ -3763,9 +3766,10 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id)
 		break;
 
 	case BTF_KIND_ENUM:
+	case BTF_KIND_ENUM64:
 		h = btf_hash_enum(t);
 		for_each_dedup_cand(d, hash_entry, h) {
-			cand_id = (__u32)(long)hash_entry->value;
+			cand_id = hash_entry->value;
 			cand = btf_type_by_id(d->btf, cand_id);
 			if (btf_equal_enum(t, cand)) {
 				new_id = cand_id;
@@ -3783,32 +3787,11 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id)
 		}
 		break;
 
-	case BTF_KIND_ENUM64:
-		h = btf_hash_enum(t);
-		for_each_dedup_cand(d, hash_entry, h) {
-			cand_id = (__u32)(long)hash_entry->value;
-			cand = btf_type_by_id(d->btf, cand_id);
-			if (btf_equal_enum64(t, cand)) {
-				new_id = cand_id;
-				break;
-			}
-			if (btf_compat_enum64(t, cand)) {
-				if (btf_is_enum_fwd(t)) {
-					/* resolve fwd to full enum */
-					new_id = cand_id;
-					break;
-				}
-				/* resolve canonical enum fwd to full enum */
-				d->map[cand_id] = type_id;
-			}
-		}
-		break;
-
 	case BTF_KIND_FWD:
 	case BTF_KIND_FLOAT:
 		h = btf_hash_common(t);
 		for_each_dedup_cand(d, hash_entry, h) {
-			cand_id = (__u32)(long)hash_entry->value;
+			cand_id = hash_entry->value;
 			cand = btf_type_by_id(d->btf, cand_id);
 			if (btf_equal_common(t, cand)) {
 				new_id = cand_id;
@@ -4099,10 +4082,8 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id,
 		return btf_equal_int_tag(cand_type, canon_type);
 
 	case BTF_KIND_ENUM:
-		return btf_compat_enum(cand_type, canon_type);
-
 	case BTF_KIND_ENUM64:
-		return btf_compat_enum64(cand_type, canon_type);
+		return btf_compat_enum(cand_type, canon_type);
 
 	case BTF_KIND_FWD:
 	case BTF_KIND_FLOAT:
@@ -4313,7 +4294,7 @@ static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id)
 
 	h = btf_hash_struct(t);
 	for_each_dedup_cand(d, hash_entry, h) {
-		__u32 cand_id = (__u32)(long)hash_entry->value;
+		__u32 cand_id = hash_entry->value;
 		int eq;
 
 		/*
@@ -4418,7 +4399,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id)
 
 		h = btf_hash_common(t);
 		for_each_dedup_cand(d, hash_entry, h) {
-			cand_id = (__u32)(long)hash_entry->value;
+			cand_id = hash_entry->value;
 			cand = btf_type_by_id(d->btf, cand_id);
 			if (btf_equal_common(t, cand)) {
 				new_id = cand_id;
@@ -4435,7 +4416,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id)
 
 		h = btf_hash_int_decl_tag(t);
 		for_each_dedup_cand(d, hash_entry, h) {
-			cand_id = (__u32)(long)hash_entry->value;
+			cand_id = hash_entry->value;
 			cand = btf_type_by_id(d->btf, cand_id);
 			if (btf_equal_int_tag(t, cand)) {
 				new_id = cand_id;
@@ -4459,7 +4440,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id)
 
 		h = btf_hash_array(t);
 		for_each_dedup_cand(d, hash_entry, h) {
-			cand_id = (__u32)(long)hash_entry->value;
+			cand_id = hash_entry->value;
 			cand = btf_type_by_id(d->btf, cand_id);
 			if (btf_equal_array(t, cand)) {
 				new_id = cand_id;
@@ -4491,7 +4472,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id)
 
 		h = btf_hash_fnproto(t);
 		for_each_dedup_cand(d, hash_entry, h) {
-			cand_id = (__u32)(long)hash_entry->value;
+			cand_id = hash_entry->value;
 			cand = btf_type_by_id(d->btf, cand_id);
 			if (btf_equal_fnproto(t, cand)) {
 				new_id = cand_id;
@@ -4528,6 +4509,134 @@ static int btf_dedup_ref_types(struct btf_dedup *d)
 }
 
 /*
+ * Collect a map from type names to type ids for all canonical structs
+ * and unions. If the same name is shared by several canonical types
+ * use a special value 0 to indicate this fact.
+ */
+static int btf_dedup_fill_unique_names_map(struct btf_dedup *d, struct hashmap *names_map)
+{
+	__u32 nr_types = btf__type_cnt(d->btf);
+	struct btf_type *t;
+	__u32 type_id;
+	__u16 kind;
+	int err;
+
+	/*
+	 * Iterate over base and split module ids in order to get all
+	 * available structs in the map.
+	 */
+	for (type_id = 1; type_id < nr_types; ++type_id) {
+		t = btf_type_by_id(d->btf, type_id);
+		kind = btf_kind(t);
+
+		if (kind != BTF_KIND_STRUCT && kind != BTF_KIND_UNION)
+			continue;
+
+		/* Skip non-canonical types */
+		if (type_id != d->map[type_id])
+			continue;
+
+		err = hashmap__add(names_map, t->name_off, type_id);
+		if (err == -EEXIST)
+			err = hashmap__set(names_map, t->name_off, 0, NULL, NULL);
+
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static int btf_dedup_resolve_fwd(struct btf_dedup *d, struct hashmap *names_map, __u32 type_id)
+{
+	struct btf_type *t = btf_type_by_id(d->btf, type_id);
+	enum btf_fwd_kind fwd_kind = btf_kflag(t);
+	__u16 cand_kind, kind = btf_kind(t);
+	struct btf_type *cand_t;
+	uintptr_t cand_id;
+
+	if (kind != BTF_KIND_FWD)
+		return 0;
+
+	/* Skip if this FWD already has a mapping */
+	if (type_id != d->map[type_id])
+		return 0;
+
+	if (!hashmap__find(names_map, t->name_off, &cand_id))
+		return 0;
+
+	/* Zero is a special value indicating that name is not unique */
+	if (!cand_id)
+		return 0;
+
+	cand_t = btf_type_by_id(d->btf, cand_id);
+	cand_kind = btf_kind(cand_t);
+	if ((cand_kind == BTF_KIND_STRUCT && fwd_kind != BTF_FWD_STRUCT) ||
+	    (cand_kind == BTF_KIND_UNION && fwd_kind != BTF_FWD_UNION))
+		return 0;
+
+	d->map[type_id] = cand_id;
+
+	return 0;
+}
+
+/*
+ * Resolve unambiguous forward declarations.
+ *
+ * The lion's share of all FWD declarations is resolved during
+ * `btf_dedup_struct_types` phase when different type graphs are
+ * compared against each other. However, if in some compilation unit a
+ * FWD declaration is not a part of a type graph compared against
+ * another type graph that declaration's canonical type would not be
+ * changed. Example:
+ *
+ * CU #1:
+ *
+ * struct foo;
+ * struct foo *some_global;
+ *
+ * CU #2:
+ *
+ * struct foo { int u; };
+ * struct foo *another_global;
+ *
+ * After `btf_dedup_struct_types` the BTF looks as follows:
+ *
+ * [1] STRUCT 'foo' size=4 vlen=1 ...
+ * [2] INT 'int' size=4 ...
+ * [3] PTR '(anon)' type_id=1
+ * [4] FWD 'foo' fwd_kind=struct
+ * [5] PTR '(anon)' type_id=4
+ *
+ * This pass assumes that such FWD declarations should be mapped to
+ * structs or unions with identical name in case if the name is not
+ * ambiguous.
+ */
+static int btf_dedup_resolve_fwds(struct btf_dedup *d)
+{
+	int i, err;
+	struct hashmap *names_map;
+
+	names_map = hashmap__new(btf_dedup_identity_hash_fn, btf_dedup_equal_fn, NULL);
+	if (IS_ERR(names_map))
+		return PTR_ERR(names_map);
+
+	err = btf_dedup_fill_unique_names_map(d, names_map);
+	if (err < 0)
+		goto exit;
+
+	for (i = 0; i < d->btf->nr_types; i++) {
+		err = btf_dedup_resolve_fwd(d, names_map, d->btf->start_id + i);
+		if (err < 0)
+			break;
+	}
+
+exit:
+	hashmap__free(names_map);
+	return err;
+}
+
+/*
  * Compact types.
  *
  * After we established for each type its corresponding canonical representative
diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
index bf0cc0e986dd..12f7039e0ab2 100644
--- a/tools/lib/bpf/btf_dump.c
+++ b/tools/lib/bpf/btf_dump.c
@@ -117,14 +117,14 @@ struct btf_dump {
 	struct btf_dump_data *typed_dump;
 };
 
-static size_t str_hash_fn(const void *key, void *ctx)
+static size_t str_hash_fn(long key, void *ctx)
 {
-	return str_hash(key);
+	return str_hash((void *)key);
 }
 
-static bool str_equal_fn(const void *a, const void *b, void *ctx)
+static bool str_equal_fn(long a, long b, void *ctx)
 {
-	return strcmp(a, b) == 0;
+	return strcmp((void *)a, (void *)b) == 0;
 }
 
 static const char *btf_name_of(const struct btf_dump *d, __u32 name_off)
@@ -225,7 +225,7 @@ static void btf_dump_free_names(struct hashmap *map)
 	struct hashmap_entry *cur;
 
 	hashmap__for_each_entry(map, cur, bkt)
-		free((void *)cur->key);
+		free((void *)cur->pkey);
 
 	hashmap__free(map);
 }
@@ -1543,11 +1543,10 @@ static size_t btf_dump_name_dups(struct btf_dump *d, struct hashmap *name_map,
 	if (!new_name)
 		return 1;
 
-	hashmap__find(name_map, orig_name, (void **)&dup_cnt);
+	hashmap__find(name_map, orig_name, &dup_cnt);
 	dup_cnt++;
 
-	err = hashmap__set(name_map, new_name, (void *)dup_cnt,
-			   (const void **)&old_name, NULL);
+	err = hashmap__set(name_map, new_name, dup_cnt, &old_name, NULL);
 	if (err)
 		free(new_name);
 
diff --git a/tools/lib/bpf/hashmap.c b/tools/lib/bpf/hashmap.c
index aeb09c288716..140ee4055676 100644
--- a/tools/lib/bpf/hashmap.c
+++ b/tools/lib/bpf/hashmap.c
@@ -128,7 +128,7 @@ static int hashmap_grow(struct hashmap *map)
 }
 
 static bool hashmap_find_entry(const struct hashmap *map,
-			       const void *key, size_t hash,
+			       const long key, size_t hash,
 			       struct hashmap_entry ***pprev,
 			       struct hashmap_entry **entry)
 {
@@ -151,18 +151,18 @@ static bool hashmap_find_entry(const struct hashmap *map,
 	return false;
 }
 
-int hashmap__insert(struct hashmap *map, const void *key, void *value,
-		    enum hashmap_insert_strategy strategy,
-		    const void **old_key, void **old_value)
+int hashmap_insert(struct hashmap *map, long key, long value,
+		   enum hashmap_insert_strategy strategy,
+		   long *old_key, long *old_value)
 {
 	struct hashmap_entry *entry;
 	size_t h;
 	int err;
 
 	if (old_key)
-		*old_key = NULL;
+		*old_key = 0;
 	if (old_value)
-		*old_value = NULL;
+		*old_value = 0;
 
 	h = hash_bits(map->hash_fn(key, map->ctx), map->cap_bits);
 	if (strategy != HASHMAP_APPEND &&
@@ -203,7 +203,7 @@ int hashmap__insert(struct hashmap *map, const void *key, void *value,
 	return 0;
 }
 
-bool hashmap__find(const struct hashmap *map, const void *key, void **value)
+bool hashmap_find(const struct hashmap *map, long key, long *value)
 {
 	struct hashmap_entry *entry;
 	size_t h;
@@ -217,8 +217,8 @@ bool hashmap__find(const struct hashmap *map, const void *key, void **value)
 	return true;
 }
 
-bool hashmap__delete(struct hashmap *map, const void *key,
-		     const void **old_key, void **old_value)
+bool hashmap_delete(struct hashmap *map, long key,
+		    long *old_key, long *old_value)
 {
 	struct hashmap_entry **pprev, *entry;
 	size_t h;
diff --git a/tools/lib/bpf/hashmap.h b/tools/lib/bpf/hashmap.h
index 10a4c4cd13cf..0a5bf1937a7c 100644
--- a/tools/lib/bpf/hashmap.h
+++ b/tools/lib/bpf/hashmap.h
@@ -40,12 +40,32 @@ static inline size_t str_hash(const char *s)
 	return h;
 }
 
-typedef size_t (*hashmap_hash_fn)(const void *key, void *ctx);
-typedef bool (*hashmap_equal_fn)(const void *key1, const void *key2, void *ctx);
+typedef size_t (*hashmap_hash_fn)(long key, void *ctx);
+typedef bool (*hashmap_equal_fn)(long key1, long key2, void *ctx);
 
+/*
+ * Hashmap interface is polymorphic, keys and values could be either
+ * long-sized integers or pointers, this is achieved as follows:
+ * - interface functions that operate on keys and values are hidden
+ *   behind auxiliary macros, e.g. hashmap_insert <-> hashmap__insert;
+ * - these auxiliary macros cast the key and value parameters as
+ *   long or long *, so the user does not have to specify the casts explicitly;
+ * - for pointer parameters (e.g. old_key) the size of the pointed
+ *   type is verified by hashmap_cast_ptr using _Static_assert;
+ * - when iterating using hashmap__for_each_* forms
+ *   hasmap_entry->key should be used for integer keys and
+ *   hasmap_entry->pkey should be used for pointer keys,
+ *   same goes for values.
+ */
 struct hashmap_entry {
-	const void *key;
-	void *value;
+	union {
+		long key;
+		const void *pkey;
+	};
+	union {
+		long value;
+		void *pvalue;
+	};
 	struct hashmap_entry *next;
 };
 
@@ -102,6 +122,13 @@ enum hashmap_insert_strategy {
 	HASHMAP_APPEND,
 };
 
+#define hashmap_cast_ptr(p) ({								\
+	_Static_assert((__builtin_constant_p((p)) ? (p) == NULL : 0) ||			\
+				sizeof(*(p)) == sizeof(long),				\
+		       #p " pointee should be a long-sized integer or a pointer");	\
+	(long *)(p);									\
+})
+
 /*
  * hashmap__insert() adds key/value entry w/ various semantics, depending on
  * provided strategy value. If a given key/value pair replaced already
@@ -109,42 +136,38 @@ enum hashmap_insert_strategy {
  * through old_key and old_value to allow calling code do proper memory
  * management.
  */
-int hashmap__insert(struct hashmap *map, const void *key, void *value,
-		    enum hashmap_insert_strategy strategy,
-		    const void **old_key, void **old_value);
+int hashmap_insert(struct hashmap *map, long key, long value,
+		   enum hashmap_insert_strategy strategy,
+		   long *old_key, long *old_value);
 
-static inline int hashmap__add(struct hashmap *map,
-			       const void *key, void *value)
-{
-	return hashmap__insert(map, key, value, HASHMAP_ADD, NULL, NULL);
-}
+#define hashmap__insert(map, key, value, strategy, old_key, old_value) \
+	hashmap_insert((map), (long)(key), (long)(value), (strategy),  \
+		       hashmap_cast_ptr(old_key),		       \
+		       hashmap_cast_ptr(old_value))
 
-static inline int hashmap__set(struct hashmap *map,
-			       const void *key, void *value,
-			       const void **old_key, void **old_value)
-{
-	return hashmap__insert(map, key, value, HASHMAP_SET,
-			       old_key, old_value);
-}
+#define hashmap__add(map, key, value) \
+	hashmap__insert((map), (key), (value), HASHMAP_ADD, NULL, NULL)
 
-static inline int hashmap__update(struct hashmap *map,
-				  const void *key, void *value,
-				  const void **old_key, void **old_value)
-{
-	return hashmap__insert(map, key, value, HASHMAP_UPDATE,
-			       old_key, old_value);
-}
+#define hashmap__set(map, key, value, old_key, old_value) \
+	hashmap__insert((map), (key), (value), HASHMAP_SET, (old_key), (old_value))
 
-static inline int hashmap__append(struct hashmap *map,
-				  const void *key, void *value)
-{
-	return hashmap__insert(map, key, value, HASHMAP_APPEND, NULL, NULL);
-}
+#define hashmap__update(map, key, value, old_key, old_value) \
+	hashmap__insert((map), (key), (value), HASHMAP_UPDATE, (old_key), (old_value))
+
+#define hashmap__append(map, key, value) \
+	hashmap__insert((map), (key), (value), HASHMAP_APPEND, NULL, NULL)
+
+bool hashmap_delete(struct hashmap *map, long key, long *old_key, long *old_value);
+
+#define hashmap__delete(map, key, old_key, old_value)		       \
+	hashmap_delete((map), (long)(key),			       \
+		       hashmap_cast_ptr(old_key),		       \
+		       hashmap_cast_ptr(old_value))
 
-bool hashmap__delete(struct hashmap *map, const void *key,
-		     const void **old_key, void **old_value);
+bool hashmap_find(const struct hashmap *map, long key, long *value);
 
-bool hashmap__find(const struct hashmap *map, const void *key, void **value);
+#define hashmap__find(map, key, value) \
+	hashmap_find((map), (long)(key), hashmap_cast_ptr(value))
 
 /*
  * hashmap__for_each_entry - iterate over all entries in hashmap
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 5d7819edf074..1d263885d635 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -5601,21 +5601,16 @@ int bpf_core_types_match(const struct btf *local_btf, __u32 local_id,
 	return __bpf_core_types_match(local_btf, local_id, targ_btf, targ_id, false, 32);
 }
 
-static size_t bpf_core_hash_fn(const void *key, void *ctx)
+static size_t bpf_core_hash_fn(const long key, void *ctx)
 {
-	return (size_t)key;
+	return key;
 }
 
-static bool bpf_core_equal_fn(const void *k1, const void *k2, void *ctx)
+static bool bpf_core_equal_fn(const long k1, const long k2, void *ctx)
 {
 	return k1 == k2;
 }
 
-static void *u32_as_hash_key(__u32 x)
-{
-	return (void *)(uintptr_t)x;
-}
-
 static int record_relo_core(struct bpf_program *prog,
 			    const struct bpf_core_relo *core_relo, int insn_idx)
 {
@@ -5658,7 +5653,6 @@ static int bpf_core_resolve_relo(struct bpf_program *prog,
 				 struct bpf_core_relo_res *targ_res)
 {
 	struct bpf_core_spec specs_scratch[3] = {};
-	const void *type_key = u32_as_hash_key(relo->type_id);
 	struct bpf_core_cand_list *cands = NULL;
 	const char *prog_name = prog->name;
 	const struct btf_type *local_type;
@@ -5675,7 +5669,7 @@ static int bpf_core_resolve_relo(struct bpf_program *prog,
 		return -EINVAL;
 
 	if (relo->kind != BPF_CORE_TYPE_ID_LOCAL &&
-	    !hashmap__find(cand_cache, type_key, (void **)&cands)) {
+	    !hashmap__find(cand_cache, local_id, &cands)) {
 		cands = bpf_core_find_cands(prog->obj, local_btf, local_id);
 		if (IS_ERR(cands)) {
 			pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld\n",
@@ -5683,7 +5677,7 @@ static int bpf_core_resolve_relo(struct bpf_program *prog,
 				local_name, PTR_ERR(cands));
 			return PTR_ERR(cands);
 		}
-		err = hashmap__set(cand_cache, type_key, cands, NULL, NULL);
+		err = hashmap__set(cand_cache, local_id, cands, NULL, NULL);
 		if (err) {
 			bpf_core_free_cands(cands);
 			return err;
@@ -5806,7 +5800,7 @@ out:
 
 	if (!IS_ERR_OR_NULL(cand_cache)) {
 		hashmap__for_each_entry(cand_cache, entry, i) {
-			bpf_core_free_cands(entry->value);
+			bpf_core_free_cands(entry->pvalue);
 		}
 		hashmap__free(cand_cache);
 	}
diff --git a/tools/lib/bpf/strset.c b/tools/lib/bpf/strset.c
index ea655318153f..2464bcbd04e0 100644
--- a/tools/lib/bpf/strset.c
+++ b/tools/lib/bpf/strset.c
@@ -19,19 +19,19 @@ struct strset {
 	struct hashmap *strs_hash;
 };
 
-static size_t strset_hash_fn(const void *key, void *ctx)
+static size_t strset_hash_fn(long key, void *ctx)
 {
 	const struct strset *s = ctx;
-	const char *str = s->strs_data + (long)key;
+	const char *str = s->strs_data + key;
 
 	return str_hash(str);
 }
 
-static bool strset_equal_fn(const void *key1, const void *key2, void *ctx)
+static bool strset_equal_fn(long key1, long key2, void *ctx)
 {
 	const struct strset *s = ctx;
-	const char *str1 = s->strs_data + (long)key1;
-	const char *str2 = s->strs_data + (long)key2;
+	const char *str1 = s->strs_data + key1;
+	const char *str2 = s->strs_data + key2;
 
 	return strcmp(str1, str2) == 0;
 }
@@ -67,7 +67,7 @@ struct strset *strset__new(size_t max_data_sz, const char *init_data, size_t ini
 			/* hashmap__add() returns EEXIST if string with the same
 			 * content already is in the hash map
 			 */
-			err = hashmap__add(hash, (void *)off, (void *)off);
+			err = hashmap__add(hash, off, off);
 			if (err == -EEXIST)
 				continue; /* duplicate */
 			if (err)
@@ -127,7 +127,7 @@ int strset__find_str(struct strset *set, const char *s)
 	new_off = set->strs_data_len;
 	memcpy(p, s, len);
 
-	if (hashmap__find(set->strs_hash, (void *)new_off, (void **)&old_off))
+	if (hashmap__find(set->strs_hash, new_off, &old_off))
 		return old_off;
 
 	return -ENOENT;
@@ -165,8 +165,8 @@ int strset__add_str(struct strset *set, const char *s)
 	 * 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(set->strs_hash, (void *)new_off, (void *)new_off,
-			      HASHMAP_ADD, (const void **)&old_off, NULL);
+	err = hashmap__insert(set->strs_hash, new_off, new_off,
+			      HASHMAP_ADD, &old_off, NULL);
 	if (err == -EEXIST)
 		return old_off; /* duplicated string, return existing offset */
 	if (err)
diff --git a/tools/lib/bpf/usdt.c b/tools/lib/bpf/usdt.c
index 28fa1b2283de..b8daae265f99 100644
--- a/tools/lib/bpf/usdt.c
+++ b/tools/lib/bpf/usdt.c
@@ -873,31 +873,27 @@ static void bpf_link_usdt_dealloc(struct bpf_link *link)
 	free(usdt_link);
 }
 
-static size_t specs_hash_fn(const void *key, void *ctx)
+static size_t specs_hash_fn(long key, void *ctx)
 {
-	const char *s = key;
-
-	return str_hash(s);
+	return str_hash((char *)key);
 }
 
-static bool specs_equal_fn(const void *key1, const void *key2, void *ctx)
+static bool specs_equal_fn(long key1, long key2, void *ctx)
 {
-	const char *s1 = key1;
-	const char *s2 = key2;
-
-	return strcmp(s1, s2) == 0;
+	return strcmp((char *)key1, (char *)key2) == 0;
 }
 
 static int allocate_spec_id(struct usdt_manager *man, struct hashmap *specs_hash,
 			    struct bpf_link_usdt *link, struct usdt_target *target,
 			    int *spec_id, bool *is_new)
 {
-	void *tmp;
+	long tmp;
+	void *new_ids;
 	int err;
 
 	/* check if we already allocated spec ID for this spec string */
 	if (hashmap__find(specs_hash, target->spec_str, &tmp)) {
-		*spec_id = (long)tmp;
+		*spec_id = tmp;
 		*is_new = false;
 		return 0;
 	}
@@ -905,17 +901,17 @@ static int allocate_spec_id(struct usdt_manager *man, struct hashmap *specs_hash
 	/* otherwise it's a new ID that needs to be set up in specs map and
 	 * returned back to usdt_manager when USDT link is detached
 	 */
-	tmp = libbpf_reallocarray(link->spec_ids, link->spec_cnt + 1, sizeof(*link->spec_ids));
-	if (!tmp)
+	new_ids = libbpf_reallocarray(link->spec_ids, link->spec_cnt + 1, sizeof(*link->spec_ids));
+	if (!new_ids)
 		return -ENOMEM;
-	link->spec_ids = tmp;
+	link->spec_ids = new_ids;
 
 	/* get next free spec ID, giving preference to free list, if not empty */
 	if (man->free_spec_cnt) {
 		*spec_id = man->free_spec_ids[man->free_spec_cnt - 1];
 
 		/* cache spec ID for current spec string for future lookups */
-		err = hashmap__add(specs_hash, target->spec_str, (void *)(long)*spec_id);
+		err = hashmap__add(specs_hash, target->spec_str, *spec_id);
 		if (err)
 			 return err;
 
@@ -928,7 +924,7 @@ static int allocate_spec_id(struct usdt_manager *man, struct hashmap *specs_hash
 		*spec_id = man->next_free_spec_id;
 
 		/* cache spec ID for current spec string for future lookups */
-		err = hashmap__add(specs_hash, target->spec_str, (void *)(long)*spec_id);
+		err = hashmap__add(specs_hash, target->spec_str, *spec_id);
 		if (err)
 			 return err;