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![Kumar Kartikeya Dwivedi](/assets/img/avatar_default.png)
This adds helpers for registering btf_id_set from modules and the bpf_check_mod_kfunc_call callback that can be used to look them up. With in kernel sets, the way this is supposed to work is, in kernel callback looks up within the in-kernel kfunc whitelist, and then defers to the dynamic BTF set lookup if it doesn't find the BTF id. If there is no in-kernel BTF id set, this callback can be used directly. Also fix includes for btf.h and bpfptr.h so that they can included in isolation. This is in preparation for their usage in tcp_bbr, tcp_cubic and tcp_dctcp modules in the next patch. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211002011757.311265-4-memxor@gmail.com
277 lines
8.3 KiB
C
277 lines
8.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/* Copyright (c) 2018 Facebook */
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#ifndef _LINUX_BTF_H
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#define _LINUX_BTF_H 1
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#include <linux/types.h>
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#include <linux/bpfptr.h>
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#include <uapi/linux/btf.h>
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#include <uapi/linux/bpf.h>
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#define BTF_TYPE_EMIT(type) ((void)(type *)0)
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#define BTF_TYPE_EMIT_ENUM(enum_val) ((void)enum_val)
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struct btf;
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struct btf_member;
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struct btf_type;
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union bpf_attr;
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struct btf_show;
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extern const struct file_operations btf_fops;
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void btf_get(struct btf *btf);
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void btf_put(struct btf *btf);
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int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr);
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struct btf *btf_get_by_fd(int fd);
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int btf_get_info_by_fd(const struct btf *btf,
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const union bpf_attr *attr,
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union bpf_attr __user *uattr);
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/* Figure out the size of a type_id. If type_id is a modifier
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* (e.g. const), it will be resolved to find out the type with size.
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*
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* For example:
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* In describing "const void *", type_id is "const" and "const"
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* refers to "void *". The return type will be "void *".
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*
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* If type_id is a simple "int", then return type will be "int".
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*
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* @btf: struct btf object
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* @type_id: Find out the size of type_id. The type_id of the return
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* type is set to *type_id.
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* @ret_size: It can be NULL. If not NULL, the size of the return
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* type is set to *ret_size.
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* Return: The btf_type (resolved to another type with size info if needed).
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* NULL is returned if type_id itself does not have size info
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* (e.g. void) or it cannot be resolved to another type that
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* has size info.
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* *type_id and *ret_size will not be changed in the
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* NULL return case.
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*/
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const struct btf_type *btf_type_id_size(const struct btf *btf,
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u32 *type_id,
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u32 *ret_size);
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/*
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* Options to control show behaviour.
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* - BTF_SHOW_COMPACT: no formatting around type information
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* - BTF_SHOW_NONAME: no struct/union member names/types
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* - BTF_SHOW_PTR_RAW: show raw (unobfuscated) pointer values;
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* equivalent to %px.
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* - BTF_SHOW_ZERO: show zero-valued struct/union members; they
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* are not displayed by default
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* - BTF_SHOW_UNSAFE: skip use of bpf_probe_read() to safely read
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* data before displaying it.
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*/
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#define BTF_SHOW_COMPACT BTF_F_COMPACT
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#define BTF_SHOW_NONAME BTF_F_NONAME
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#define BTF_SHOW_PTR_RAW BTF_F_PTR_RAW
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#define BTF_SHOW_ZERO BTF_F_ZERO
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#define BTF_SHOW_UNSAFE (1ULL << 4)
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void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
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struct seq_file *m);
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int btf_type_seq_show_flags(const struct btf *btf, u32 type_id, void *obj,
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struct seq_file *m, u64 flags);
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/*
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* Copy len bytes of string representation of obj of BTF type_id into buf.
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*
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* @btf: struct btf object
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* @type_id: type id of type obj points to
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* @obj: pointer to typed data
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* @buf: buffer to write to
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* @len: maximum length to write to buf
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* @flags: show options (see above)
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*
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* Return: length that would have been/was copied as per snprintf, or
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* negative error.
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*/
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int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
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char *buf, int len, u64 flags);
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int btf_get_fd_by_id(u32 id);
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u32 btf_obj_id(const struct btf *btf);
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bool btf_is_kernel(const struct btf *btf);
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bool btf_is_module(const struct btf *btf);
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struct module *btf_try_get_module(const struct btf *btf);
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u32 btf_nr_types(const struct btf *btf);
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bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
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const struct btf_member *m,
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u32 expected_offset, u32 expected_size);
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int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t);
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int btf_find_timer(const struct btf *btf, const struct btf_type *t);
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bool btf_type_is_void(const struct btf_type *t);
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s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind);
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const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
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u32 id, u32 *res_id);
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const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
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u32 id, u32 *res_id);
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const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
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u32 id, u32 *res_id);
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const struct btf_type *
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btf_resolve_size(const struct btf *btf, const struct btf_type *type,
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u32 *type_size);
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const char *btf_type_str(const struct btf_type *t);
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#define for_each_member(i, struct_type, member) \
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for (i = 0, member = btf_type_member(struct_type); \
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i < btf_type_vlen(struct_type); \
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i++, member++)
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#define for_each_vsi(i, datasec_type, member) \
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for (i = 0, member = btf_type_var_secinfo(datasec_type); \
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i < btf_type_vlen(datasec_type); \
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i++, member++)
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static inline bool btf_type_is_ptr(const struct btf_type *t)
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{
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return BTF_INFO_KIND(t->info) == BTF_KIND_PTR;
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}
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static inline bool btf_type_is_int(const struct btf_type *t)
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{
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return BTF_INFO_KIND(t->info) == BTF_KIND_INT;
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}
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static inline bool btf_type_is_small_int(const struct btf_type *t)
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{
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return btf_type_is_int(t) && t->size <= sizeof(u64);
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}
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static inline bool btf_type_is_enum(const struct btf_type *t)
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{
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return BTF_INFO_KIND(t->info) == BTF_KIND_ENUM;
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}
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static inline bool btf_type_is_scalar(const struct btf_type *t)
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{
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return btf_type_is_int(t) || btf_type_is_enum(t);
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}
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static inline bool btf_type_is_typedef(const struct btf_type *t)
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{
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return BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF;
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}
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static inline bool btf_type_is_func(const struct btf_type *t)
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{
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return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC;
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}
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static inline bool btf_type_is_func_proto(const struct btf_type *t)
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{
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return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC_PROTO;
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}
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static inline bool btf_type_is_var(const struct btf_type *t)
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{
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return BTF_INFO_KIND(t->info) == BTF_KIND_VAR;
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}
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/* union is only a special case of struct:
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* all its offsetof(member) == 0
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*/
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static inline bool btf_type_is_struct(const struct btf_type *t)
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{
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u8 kind = BTF_INFO_KIND(t->info);
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return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
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}
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static inline u16 btf_type_vlen(const struct btf_type *t)
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{
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return BTF_INFO_VLEN(t->info);
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}
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static inline u16 btf_func_linkage(const struct btf_type *t)
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{
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return BTF_INFO_VLEN(t->info);
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}
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static inline bool btf_type_kflag(const struct btf_type *t)
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{
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return BTF_INFO_KFLAG(t->info);
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}
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static inline u32 btf_member_bit_offset(const struct btf_type *struct_type,
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const struct btf_member *member)
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{
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return btf_type_kflag(struct_type) ? BTF_MEMBER_BIT_OFFSET(member->offset)
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: member->offset;
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}
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static inline u32 btf_member_bitfield_size(const struct btf_type *struct_type,
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const struct btf_member *member)
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{
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return btf_type_kflag(struct_type) ? BTF_MEMBER_BITFIELD_SIZE(member->offset)
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: 0;
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}
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static inline const struct btf_member *btf_type_member(const struct btf_type *t)
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{
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return (const struct btf_member *)(t + 1);
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}
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static inline const struct btf_var_secinfo *btf_type_var_secinfo(
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const struct btf_type *t)
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{
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return (const struct btf_var_secinfo *)(t + 1);
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}
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#ifdef CONFIG_BPF_SYSCALL
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struct bpf_prog;
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const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id);
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const char *btf_name_by_offset(const struct btf *btf, u32 offset);
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struct btf *btf_parse_vmlinux(void);
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struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog);
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#else
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static inline const struct btf_type *btf_type_by_id(const struct btf *btf,
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u32 type_id)
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{
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return NULL;
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}
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static inline const char *btf_name_by_offset(const struct btf *btf,
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u32 offset)
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{
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return NULL;
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}
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#endif
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struct kfunc_btf_id_set {
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struct list_head list;
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struct btf_id_set *set;
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struct module *owner;
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};
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struct kfunc_btf_id_list;
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#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
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void register_kfunc_btf_id_set(struct kfunc_btf_id_list *l,
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struct kfunc_btf_id_set *s);
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void unregister_kfunc_btf_id_set(struct kfunc_btf_id_list *l,
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struct kfunc_btf_id_set *s);
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bool bpf_check_mod_kfunc_call(struct kfunc_btf_id_list *klist, u32 kfunc_id,
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struct module *owner);
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#else
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static inline void register_kfunc_btf_id_set(struct kfunc_btf_id_list *l,
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struct kfunc_btf_id_set *s)
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{
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}
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static inline void unregister_kfunc_btf_id_set(struct kfunc_btf_id_list *l,
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struct kfunc_btf_id_set *s)
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{
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}
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static inline bool bpf_check_mod_kfunc_call(struct kfunc_btf_id_list *klist,
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u32 kfunc_id, struct module *owner)
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{
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return false;
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}
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#endif
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#define DEFINE_KFUNC_BTF_ID_SET(set, name) \
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struct kfunc_btf_id_set name = { LIST_HEAD_INIT(name.list), (set), \
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THIS_MODULE }
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#endif
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