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-rw-r--r--Documentation/bpf/kfuncs.rst4
-rw-r--r--tools/bpf/resolve_btfids/main.c72
-rw-r--r--tools/testing/selftests/bpf/prog_tests/resolve_btfids.c41
-rw-r--r--tools/testing/selftests/bpf/progs/btf_data.c20
4 files changed, 99 insertions, 38 deletions
diff --git a/Documentation/bpf/kfuncs.rst b/Documentation/bpf/kfuncs.rst
index 1004eb0bec61..10e725cbe64c 100644
--- a/Documentation/bpf/kfuncs.rst
+++ b/Documentation/bpf/kfuncs.rst
@@ -513,8 +513,8 @@ At kernel build time the ``resolve_btfids`` tool finds all kfuncs declared with
``BTF_KFUNCS_START()`` and emits their BTF annotations into the kernel's BTF.
For each kfunc it emits a ``bpf_kfunc`` BTF decl tag, a ``bpf_fastcall`` decl
tag when the kfunc is flagged ``KF_FASTCALL``, and the ``address_space(1)`` type
-attribute on the return value and/or arguments flagged ``KF_ARENA_RET``,
-``KF_ARENA_ARG1`` or ``KF_ARENA_ARG2`` (see section 2.8).
+attribute on the return value and/or arguments that use arena pointers (see
+sections 2.3.8 and 2.8).
2.7 Specifying no-cast aliases with ___init
--------------------------------------------
diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c
index d2e4176339da..37d7e7224207 100644
--- a/tools/bpf/resolve_btfids/main.c
+++ b/tools/bpf/resolve_btfids/main.c
@@ -64,8 +64,8 @@
* each such kfunc it:
*
* - emits a "bpf_kfunc" decl tag, and "bpf_fastcall" when KF_FASTCALL is set;
- * - wraps the return value and/or arguments flagged KF_ARENA_RET,
- * KF_ARENA_ARG1 or KF_ARENA_ARG2 with the "address_space(1)" type attribute;
+ * - wraps the return value and/or arguments that use arena pointers
+ * with the "address_space(1)" type attribute;
* - rewrites the prototype of KF_IMPLICIT_ARGS kfuncs.
*
* These kfunc annotations were historically produced by pahole.
@@ -182,6 +182,8 @@ struct object {
#define KF_IMPLICIT_ARGS (1 << 16)
#define KF_IMPL_SUFFIX "_impl"
#define TYPE_ATTR_ARENA "address_space(1)"
+#define PARAM_SUFFIX_ARENA "__arena"
+#define PARAM_SUFFIX_ARENA_NULLABLE "__arena__nullable"
struct kfunc {
struct rb_node rb_node;
@@ -1067,6 +1069,22 @@ static int collect_decl_tags(struct btf2btf_context *ctx)
return 0;
}
+static bool param_name_has_suffix(const char *name, const char *suffix)
+{
+ size_t name_len = strlen(name);
+ size_t suffix_len = strlen(suffix);
+
+ return name_len >= suffix_len && !strcmp(name + name_len - suffix_len, suffix);
+}
+
+static bool is_arena_param(const struct btf *btf, const struct btf_param *param)
+{
+ const char *name = btf__name_by_offset(btf, param->name_off);
+
+ return param_name_has_suffix(name, PARAM_SUFFIX_ARENA) ||
+ param_name_has_suffix(name, PARAM_SUFFIX_ARENA_NULLABLE);
+}
+
static int collect_kfuncs(struct object *obj, struct btf2btf_context *ctx)
{
Elf_Data *idlist = obj->efile.idlist;
@@ -1299,8 +1317,12 @@ add_new_proto:
return 0;
}
-static bool is_arena_arg(struct kfunc *kfunc, u32 idx)
+static bool is_arena_arg(const struct btf *btf, const struct kfunc *kfunc,
+ const struct btf_param *param, u32 idx)
{
+ if (is_arena_param(btf, param))
+ return true;
+
switch (idx) {
case 0:
return kfunc->flags & KF_ARENA_ARG1;
@@ -1339,23 +1361,36 @@ static s32 arena_tag_ptr(struct btf *btf, u32 ptr_id, struct kfunc *kfunc)
}
/*
- * Add a FUNC_PROTO for @kfunc with each relevant pointer tagged with
- * an "address_space(1)" attribute. The original proto may be shared
- * with other FUNCs, so it is never modified in place.
+ * Add a FUNC_PROTO for @kfunc with each arena pointer tagged with an
+ * "address_space(1)" attribute. The original proto may be shared with
+ * other FUNCs, so it is never modified in place. Returns the original
+ * proto id when @kfunc has no arena return value or arguments.
*/
static s32 add_arena_tagged_proto(struct btf *btf, struct kfunc *kfunc)
{
const struct btf_type *func = btf__type_by_id(btf, kfunc->btf_id);
u32 proto_id = func->type;
const struct btf_type *proto = btf__type_by_id(btf, proto_id);
+ const struct btf_param *params = btf_params(proto);
u32 nr_params = btf_vlen(proto);
s32 ret_type_id = proto->type;
const struct btf_type *t;
- struct btf_param *params;
+ struct btf_param *tag_params;
s32 new_proto_id, id;
const char *name;
+ bool has_arena_arg = false;
int err, i;
+ for (i = 0; i < nr_params; i++) {
+ if (is_arena_arg(btf, kfunc, &params[i], i)) {
+ has_arena_arg = true;
+ break;
+ }
+ }
+
+ if (!(kfunc->flags & KF_ARENA_RET) && !has_arena_arg)
+ return proto_id;
+
if (kfunc->flags & KF_ARENA_RET) {
ret_type_id = arena_tag_ptr(btf, ret_type_id, kfunc);
if (ret_type_id < 0)
@@ -1383,19 +1418,18 @@ static s32 add_arena_tagged_proto(struct btf *btf, struct kfunc *kfunc)
}
for (i = 0; i < nr_params; i++) {
- if (!is_arena_arg(kfunc, i))
- continue;
-
t = btf__type_by_id(btf, new_proto_id);
- params = btf_params(t);
+ tag_params = btf_params(t);
+ if (!is_arena_arg(btf, kfunc, &tag_params[i], i))
+ continue;
- id = arena_tag_ptr(btf, params[i].type, kfunc);
+ id = arena_tag_ptr(btf, tag_params[i].type, kfunc);
if (id < 0)
return id;
t = btf__type_by_id(btf, new_proto_id);
- params = btf_params(t);
- params[i].type = id;
+ tag_params = btf_params(t);
+ tag_params[i].type = id;
}
pr_debug("added arena-tagged proto for kfunc %s: %d\n", kfunc->name, new_proto_id);
@@ -1403,7 +1437,7 @@ static s32 add_arena_tagged_proto(struct btf *btf, struct kfunc *kfunc)
return new_proto_id;
}
-static int process_kfunc_with_arena_flags(struct btf2btf_context *ctx,
+static int process_kfunc_with_arena_attrs(struct btf2btf_context *ctx,
struct kfunc *kfunc)
{
struct btf_type *t;
@@ -1463,11 +1497,9 @@ static int btf2btf(struct object *obj)
goto out;
}
- if (kfunc->flags & (KF_ARENA_RET | KF_ARENA_ARG1 | KF_ARENA_ARG2)) {
- err = process_kfunc_with_arena_flags(&ctx, kfunc);
- if (err)
- goto out;
- }
+ err = process_kfunc_with_arena_attrs(&ctx, kfunc);
+ if (err)
+ goto out;
}
err = 0;
diff --git a/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c b/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c
index 732cfed35e1c..3f9949e8227d 100644
--- a/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c
+++ b/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c
@@ -15,6 +15,7 @@
#define DECL_TAG_FASTCALL "bpf_fastcall"
#define DECL_TAG_KFUNC "bpf_kfunc"
#define TYPE_ATTR_ARENA "address_space(1)"
+#define ARENA_ARG(n) (1U << (n))
#ifndef KF_FASTCALL
#define KF_FASTCALL (1 << 12)
@@ -49,13 +50,20 @@ struct kfunc_symbol {
const char *name;
s32 id;
u32 flags;
+ u32 arena_args;
+ bool arena_ret;
};
static struct kfunc_symbol kfunc_symbols[] = {
- { "kfunc_a", -1, 0 },
- { "kfunc_b", -1, KF_FASTCALL },
- { "kfunc_c", -1, KF_ARENA_RET | KF_ARENA_ARG1 | KF_ARENA_ARG2 },
- { "kfunc_d", -1, KF_ARENA_ARG2 },
+ { "kfunc_a", -1, 0, 0, false },
+ { "kfunc_b", -1, KF_FASTCALL, 0, false },
+ { "kfunc_c", -1, KF_ARENA_RET | KF_ARENA_ARG1 | KF_ARENA_ARG2,
+ ARENA_ARG(0) | ARENA_ARG(1), true },
+ { "kfunc_d", -1, KF_ARENA_ARG2, ARENA_ARG(1), false },
+ { "kfunc_e", -1, 0, ARENA_ARG(0) | ARENA_ARG(1) | ARENA_ARG(2) |
+ ARENA_ARG(3) | ARENA_ARG(4), false },
+ { "kfunc_f", -1, 0, ARENA_ARG(1), false },
+ { "kfunc_g", -1, KF_ARENA_RET, ARENA_ARG(0) | ARENA_ARG(1), true },
};
/* Align the .BTF_ids section to 4 bytes */
@@ -105,6 +113,9 @@ BTF_ID_FLAGS(func, kfunc_a)
BTF_ID_FLAGS(func, kfunc_b, KF_FASTCALL)
BTF_ID_FLAGS(func, kfunc_c, KF_ARENA_RET | KF_ARENA_ARG1 | KF_ARENA_ARG2)
BTF_ID_FLAGS(func, kfunc_d, KF_ARENA_ARG2)
+BTF_ID_FLAGS(func, kfunc_e)
+BTF_ID_FLAGS(func, kfunc_f)
+BTF_ID_FLAGS(func, kfunc_g, KF_ARENA_RET)
BTF_KFUNCS_END(test_kfunc_set)
/*
@@ -112,6 +123,9 @@ BTF_KFUNCS_END(test_kfunc_set)
* actually sort at least one of the two sets.
*/
BTF_KFUNCS_START(test_kfunc_set_rev)
+BTF_ID_FLAGS(func, kfunc_g, KF_ARENA_RET)
+BTF_ID_FLAGS(func, kfunc_f)
+BTF_ID_FLAGS(func, kfunc_e)
BTF_ID_FLAGS(func, kfunc_d, KF_ARENA_ARG2)
BTF_ID_FLAGS(func, kfunc_c, KF_ARENA_RET | KF_ARENA_ARG1 | KF_ARENA_ARG2)
BTF_ID_FLAGS(func, kfunc_b, KF_FASTCALL)
@@ -301,15 +315,15 @@ void test_resolve_btfids(void)
}
/*
- * Check resolve_btfids wrapped exactly the arena-flagged return/args
- * with the address_space(1) type attribute, and left other
+ * Check resolve_btfids wrapped exactly the arena-flagged or suffixed
+ * return/args with the address_space(1) type attribute, and left other
* pointers/returns untouched.
*/
for (i = 0; i < ARRAY_SIZE(kfunc_symbols); i++) {
const struct btf_type *fn, *proto;
const struct btf_param *params;
const char *name = kfunc_symbols[i].name;
- u32 fl = kfunc_symbols[i].flags;
+ u32 arena_args = kfunc_symbols[i].arena_args;
__u32 nr;
fn = btf__type_by_id(btf, kfunc_symbols[i].id);
@@ -322,15 +336,10 @@ void test_resolve_btfids(void)
nr = btf_vlen(proto);
ASSERT_EQ(is_arena_tagged_ptr(btf, proto->type),
- !!(fl & KF_ARENA_RET), name);
- if (nr > 0) {
- ASSERT_EQ(is_arena_tagged_ptr(btf, params[0].type),
- !!(fl & KF_ARENA_ARG1), name);
- }
- if (nr > 1) {
- ASSERT_EQ(is_arena_tagged_ptr(btf, params[1].type),
- !!(fl & KF_ARENA_ARG2), name);
- }
+ kfunc_symbols[i].arena_ret, name);
+ for (j = 0; j < nr; j++)
+ ASSERT_EQ(is_arena_tagged_ptr(btf, params[j].type),
+ !!(arena_args & ARENA_ARG(j)), name);
}
out:
diff --git a/tools/testing/selftests/bpf/progs/btf_data.c b/tools/testing/selftests/bpf/progs/btf_data.c
index ec34f7a6e038..8082c13490ab 100644
--- a/tools/testing/selftests/bpf/progs/btf_data.c
+++ b/tools/testing/selftests/bpf/progs/btf_data.c
@@ -68,3 +68,23 @@ int kfunc_d(struct root_struct *a, struct root_struct *b)
{
return 0;
}
+
+int kfunc_e(struct root_struct *a__arena,
+ struct root_struct *b__arena__nullable,
+ struct root_struct *c__arena,
+ struct root_struct *d__arena__nullable,
+ struct root_struct *e__arena)
+{
+ return 0;
+}
+
+int kfunc_f(struct root_struct *a, struct root_struct *b__arena, int flags)
+{
+ return 0;
+}
+
+struct root_struct *kfunc_g(struct root_struct *a__arena,
+ struct root_struct *b__arena__nullable)
+{
+ return a__arena;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2026-09-17 13:18:49 +0000