From: Kui-Feng Lee <thinker.li@xxxxxxxxx>
Provide registration functions to add/remove struct_ops types.
Currently, it does linear search to find a struct_ops type. It should be
fine for now since we don't have many struct_ops types.
Signed-off-by: Kui-Feng Lee <thinker.li@xxxxxxxxx>
---
include/linux/bpf.h | 13 ++++
include/linux/btf.h | 1 +
kernel/bpf/bpf_struct_ops.c | 115 ++++++++++++++++++++++++++++++++++--
kernel/bpf/btf.c | 2 +-
4 files changed, 126 insertions(+), 5 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 024e8b28c34b..10f98f0ddc77 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1561,6 +1561,8 @@ struct btf_member;
* @init: A callback that is invoked a single time, and before any other
* callback, to initialize the structure. A nonzero return value means
* the subsystem could not be initialized.
+ * @uninit: A callback that is invoked after any other
+ * callback to release resources used by the subsystem.
* @check_member: When defined, a callback invoked by the verifier to allow
* the subsystem to determine if an entry in the struct_ops map
* is valid. A nonzero return value means that the map is
@@ -1601,6 +1603,7 @@ struct btf_member;
struct bpf_struct_ops {
const struct bpf_verifier_ops *verifier_ops;
int (*init)(struct btf *btf);
+ int (*uninit)(void);
int (*check_member)(const struct btf_type *t,
const struct btf_member *member,
const struct bpf_prog *prog);
@@ -1619,6 +1622,11 @@ struct bpf_struct_ops {
u32 value_id;
};
+struct bpf_struct_ops_mod {
+ struct module *owner;
+ struct bpf_struct_ops *st_ops;
+};
+
#if defined(CONFIG_BPF_JIT) && defined(CONFIG_BPF_SYSCALL)
#define BPF_MODULE_OWNER ((void *)((0xeB9FUL << 2) + POISON_POINTER_DELTA))
const struct bpf_struct_ops *bpf_struct_ops_find(u32 type_id);
@@ -3183,4 +3191,9 @@ static inline gfp_t bpf_memcg_flags(gfp_t flags)
return flags;
}
+#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
+int register_bpf_struct_ops(struct bpf_struct_ops_mod *mod);
+int unregister_bpf_struct_ops(struct bpf_struct_ops_mod *mod);
+#endif
+
#endif /* _LINUX_BPF_H */
diff --git a/include/linux/btf.h b/include/linux/btf.h
index 928113a80a95..d6ed3d99ba41 100644
--- a/include/linux/btf.h
+++ b/include/linux/btf.h
@@ -200,6 +200,7 @@ u32 btf_obj_id(const struct btf *btf);
bool btf_is_kernel(const struct btf *btf);
bool btf_is_module(const struct btf *btf);
struct module *btf_try_get_module(const struct btf *btf);
+struct btf *btf_get_module_btf(const struct module *module);
u32 btf_nr_types(const struct btf *btf);
bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
const struct btf_member *m,
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
index 1662875e0ebe..9be6e07ccba5 100644
--- a/kernel/bpf/bpf_struct_ops.c
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -92,12 +92,15 @@ enum {
__NR_BPF_STRUCT_OPS_TYPE,
};
-static struct bpf_struct_ops * const bpf_struct_ops[] = {
+static struct bpf_struct_ops *bpf_struct_ops_static[] = {
#define BPF_STRUCT_OPS_TYPE(_name) \
[BPF_STRUCT_OPS_TYPE_##_name] = &bpf_##_name,
#include "bpf_struct_ops_types.h"
#undef BPF_STRUCT_OPS_TYPE
};
+static struct bpf_struct_ops **bpf_struct_ops;
+static int bpf_struct_ops_num;
+static int bpf_struct_ops_capacity;
const struct bpf_verifier_ops bpf_struct_ops_verifier_ops = {
};
@@ -212,12 +215,116 @@ void bpf_struct_ops_init(struct btf *btf, struct bpf_verifier_log *log)
}
module_type = btf_type_by_id(btf, module_id);
- for (i = 0; i < ARRAY_SIZE(bpf_struct_ops); i++) {
+ bpf_struct_ops_num = ARRAY_SIZE(bpf_struct_ops_static);
+ bpf_struct_ops_capacity = bpf_struct_ops_num;
+ bpf_struct_ops = bpf_struct_ops_static;
+
+ for (i = 0; i < bpf_struct_ops_num; i++) {
st_ops = bpf_struct_ops[i];
bpf_struct_ops_init_one(st_ops, btf, log);
}
}
+static int add_struct_ops(struct bpf_struct_ops *st_ops)
+{
+ struct bpf_struct_ops **new_ops;
+ int i;
+
+ for (i = 0; i < bpf_struct_ops_num; i++) {
+ if (bpf_struct_ops[i] == st_ops)
+ return -EEXIST;
+ if (strcmp(bpf_struct_ops[i]->name, st_ops->name) == 0)
+ return -EEXIST;
+ }
+
+ if (bpf_struct_ops_num == bpf_struct_ops_capacity) {
+ if (bpf_struct_ops == bpf_struct_ops_static) {
+ new_ops = kmalloc_array(((bpf_struct_ops_capacity + 0x7) & ~0x7) * 2,
+ sizeof(*new_ops),
+ GFP_KERNEL);
+ if (!new_ops)
+ return -ENOMEM;
+ memcpy(new_ops, bpf_struct_ops,
+ sizeof(*new_ops) * bpf_struct_ops_num);
+ } else {
+ new_ops = krealloc_array(bpf_struct_ops,
+ bpf_struct_ops_capacity * 2,
+ sizeof(*new_ops),
+ GFP_KERNEL);
+ if (!new_ops)
+ return -ENOMEM;
+ }
+ bpf_struct_ops = new_ops;
+ bpf_struct_ops_capacity *= 2;
+ }
+
+ bpf_struct_ops[bpf_struct_ops_num++] = st_ops;
+ return 0;
+}
+
+static int remove_struct_ops(struct bpf_struct_ops *st_ops)
+{
+ int i;
+
+ for (i = 0; i < bpf_struct_ops_num; i++) {
+ if (bpf_struct_ops[i] == st_ops) {
+ bpf_struct_ops_num--;
+ bpf_struct_ops[i] = bpf_struct_ops[bpf_struct_ops_num];
+ return 0;
+ }
+ }
+
+ return -ENOENT;
+}
+
+int register_bpf_struct_ops(struct bpf_struct_ops_mod *mod)
+{
+ struct bpf_struct_ops *st_ops = mod->st_ops;
+ struct bpf_verifier_log *log;
+ struct btf *btf;
+ int err;
+
+ if (mod->st_ops == NULL ||
+ mod->owner == NULL)
+ return -EINVAL;
+
+ log = kzalloc(sizeof(*log), GFP_KERNEL | __GFP_NOWARN);
+ if (!log) {
+ err = -ENOMEM;
+ goto errout;
+ }
+
+ log->level = BPF_LOG_KERNEL;
+
+ btf = btf_get_module_btf(mod->owner);
+ if (!btf) {
+ err = -EINVAL;
+ goto errout;
+ }
+
+ bpf_struct_ops_init_one(st_ops, btf, log);
+ err = add_struct_ops(st_ops);
+
+errout:
+ kfree(log);
+
+ return err;
+}
+EXPORT_SYMBOL(register_bpf_struct_ops);
+
+int unregister_bpf_struct_ops(struct bpf_struct_ops_mod *mod)
+{
+ struct bpf_struct_ops *st_ops = mod->st_ops;
+ int err;
+
+ err = remove_struct_ops(st_ops);
+ if (!err && st_ops->uninit)
+ err = st_ops->uninit();
+
+ return err;
+}
+EXPORT_SYMBOL(unregister_bpf_struct_ops);
+
extern struct btf *btf_vmlinux;
static const struct bpf_struct_ops *
@@ -228,7 +335,7 @@ bpf_struct_ops_find_value(u32 value_id)
if (!value_id || !btf_vmlinux)
return NULL;
- for (i = 0; i < ARRAY_SIZE(bpf_struct_ops); i++) {
+ for (i = 0; i < bpf_struct_ops_num; i++) {
if (bpf_struct_ops[i]->value_id == value_id)
return bpf_struct_ops[i];
}
@@ -243,7 +350,7 @@ const struct bpf_struct_ops *bpf_struct_ops_find(u32 type_id)
if (!type_id || !btf_vmlinux)
return NULL;
- for (i = 0; i < ARRAY_SIZE(bpf_struct_ops); i++) {
+ for (i = 0; i < bpf_struct_ops_num; i++) {
if (bpf_struct_ops[i]->type_id == type_id)
return bpf_struct_ops[i];
}
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 1095bbe29859..55d76d85c6ec 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -7498,7 +7498,7 @@ struct module *btf_try_get_module(const struct btf *btf)
/* Returns struct btf corresponding to the struct module.
* This function can return NULL or ERR_PTR.
*/
-static struct btf *btf_get_module_btf(const struct module *module)
+struct btf *btf_get_module_btf(const struct module *module)
{
#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
struct btf_module *btf_mod, *tmp;
--
2.34.1
