Split __register_btf_kfunc_id_set(), register_btf_id_dtor_kfuncs() and __register_bpf_struct_ops() into the part that looks up the BTF for the owner and the part that adds the registration to a given BTF: btf_kfunc_id_set_add(), btf_dtor_kfuncs_add() and btf_struct_ops_add().
In is_valid_value_type(), look up bpf_struct_ops_common_value in the btf the function was given rather than in the btf_vmlinux global. The id is a vmlinux id and a module BTF resolves it through its base, so the result is the same; the function already uses the passed btf for every other lookup. No functional change. With CONFIG_DEBUG_INFO_BTF=m, registrations made from initcalls before the vmlinux BTF is available are queued and applied later by the BTF parsing code, which needs the add-to-this-btf half on its own; the struct_ops ones are applied before the parsed vmlinux BTF is published, i.e. while btf_vmlinux is still NULL. Signed-off-by: Jay Wang <[email protected]> --- kernel/bpf/bpf_struct_ops.c | 3 +- kernel/bpf/btf.c | 91 ++++++++++++++++++++++--------------- 2 files changed, 57 insertions(+), 37 deletions(-) diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c index 1178acd72296..bf3004908d15 100644 --- a/kernel/bpf/bpf_struct_ops.c +++ b/kernel/bpf/bpf_struct_ops.c @@ -103,7 +103,8 @@ static bool is_valid_value_type(struct btf *btf, s32 value_id, } member = btf_type_member(vt); mt = btf_type_by_id(btf, member->type); - common_value_type = btf_type_by_id(btf_vmlinux, + /* a vmlinux id resolves through the base BTF of a module BTF too */ + common_value_type = btf_type_by_id(btf, st_ops_ids[IDX_ST_OPS_COMMON_VALUE_ID]); if (mt != common_value_type) { pr_warn("The first member of %s should be bpf_struct_ops_common_value\n", diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index a6634237dc89..c3c1421208b4 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -9313,11 +9313,26 @@ u32 *btf_kfunc_is_modify_return(const struct btf *btf, u32 kfunc_btf_id, return btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_FMODRET, kfunc_btf_id); } +static int btf_kfunc_id_set_add(struct btf *btf, enum btf_kfunc_hook hook, + const struct btf_kfunc_id_set *kset) +{ + int ret, i; + + for (i = 0; i < kset->set->cnt; i++) { + ret = btf_check_kfunc_protos(btf, btf_relocate_id(btf, kset->set->pairs[i].id), + kset->set->pairs[i].flags); + if (ret) + return ret; + } + + return btf_populate_kfunc_set(btf, hook, kset); +} + static int __register_btf_kfunc_id_set(enum btf_kfunc_hook hook, const struct btf_kfunc_id_set *kset) { struct btf *btf; - int ret, i; + int ret; btf = btf_get_module_btf(kset->owner); if (!btf) @@ -9325,16 +9340,7 @@ static int __register_btf_kfunc_id_set(enum btf_kfunc_hook hook, if (IS_ERR(btf)) return PTR_ERR(btf); - for (i = 0; i < kset->set->cnt; i++) { - ret = btf_check_kfunc_protos(btf, btf_relocate_id(btf, kset->set->pairs[i].id), - kset->set->pairs[i].flags); - if (ret) - goto err_out; - } - - ret = btf_populate_kfunc_set(btf, hook, kset); - -err_out: + ret = btf_kfunc_id_set_add(btf, hook, kset); btf_put(btf); return ret; } @@ -9426,21 +9432,13 @@ static int btf_check_dtor_kfuncs(struct btf *btf, const struct btf_id_dtor_kfunc return 0; } -/* This function must be invoked only from initcalls/module init functions */ -int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_cnt, - struct module *owner) +static int btf_dtor_kfuncs_add(struct btf *btf, const struct btf_id_dtor_kfunc *dtors, + u32 add_cnt) { struct btf_id_dtor_kfunc_tab *tab; - struct btf *btf; u32 tab_cnt, i; int ret; - btf = btf_get_module_btf(owner); - if (!btf) - return check_btf_kconfigs(owner, "dtor kfuncs"); - if (IS_ERR(btf)) - return PTR_ERR(btf); - if (add_cnt >= BTF_DTOR_KFUNC_MAX_CNT) { pr_err("cannot register more than %d kfunc destructors\n", BTF_DTOR_KFUNC_MAX_CNT); ret = -E2BIG; @@ -9497,6 +9495,23 @@ int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_c end: if (ret) btf_free_dtor_kfunc_tab(btf); + return ret; +} + +/* This function must be invoked only from initcalls/module init functions */ +int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_cnt, + struct module *owner) +{ + struct btf *btf; + int ret; + + btf = btf_get_module_btf(owner); + if (!btf) + return check_btf_kconfigs(owner, "dtor kfuncs"); + if (IS_ERR(btf)) + return PTR_ERR(btf); + + ret = btf_dtor_kfuncs_add(btf, dtors, add_cnt); btf_put(btf); return ret; } @@ -10135,32 +10150,36 @@ bpf_struct_ops_find(struct btf *btf, u32 type_id) return NULL; } -int __register_bpf_struct_ops(struct bpf_struct_ops *st_ops) +static int btf_struct_ops_add(struct btf *btf, struct bpf_struct_ops *st_ops) { struct bpf_verifier_log *log; - struct btf *btf; - int err = 0; - - btf = btf_get_module_btf(st_ops->owner); - if (!btf) - return check_btf_kconfigs(st_ops->owner, "struct_ops"); - if (IS_ERR(btf)) - return PTR_ERR(btf); + int err; log = kzalloc_obj(*log, GFP_KERNEL | __GFP_NOWARN); - if (!log) { - err = -ENOMEM; - goto errout; - } + if (!log) + return -ENOMEM; log->level = BPF_LOG_KERNEL; err = btf_add_struct_ops(btf, st_ops, log); -errout: kfree(log); - btf_put(btf); + return err; +} +int __register_bpf_struct_ops(struct bpf_struct_ops *st_ops) +{ + struct btf *btf; + int err; + + btf = btf_get_module_btf(st_ops->owner); + if (!btf) + return check_btf_kconfigs(st_ops->owner, "struct_ops"); + if (IS_ERR(btf)) + return PTR_ERR(btf); + + err = btf_struct_ops_add(btf, st_ops); + btf_put(btf); return err; } EXPORT_SYMBOL_GPL(__register_bpf_struct_ops); -- 2.47.3
