1/* SPDX-License-Identifier: GPL-2.0 */
  2/* Copyright (c) 2018 Facebook */
  3
  4#ifndef _LINUX_BTF_H
  5#define _LINUX_BTF_H 1
  6
  7#include <linux/types.h>
  8#include <uapi/linux/btf.h>
  9#include <uapi/linux/bpf.h>
 10
 11#define BTF_TYPE_EMIT(type) ((void)(type *)0)
 12#define BTF_TYPE_EMIT_ENUM(enum_val) ((void)enum_val)
 13
 14struct btf;
 15struct btf_member;
 16struct btf_type;
 17union bpf_attr;
 18struct btf_show;
 19
 20extern const struct file_operations btf_fops;
 21
 22void btf_get(struct btf *btf);
 23void btf_put(struct btf *btf);
 24int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr);
 25struct btf *btf_get_by_fd(int fd);
 26int btf_get_info_by_fd(const struct btf *btf,
 27		       const union bpf_attr *attr,
 28		       union bpf_attr __user *uattr);
 29/* Figure out the size of a type_id.  If type_id is a modifier
 30 * (e.g. const), it will be resolved to find out the type with size.
 31 *
 32 * For example:
 33 * In describing "const void *",  type_id is "const" and "const"
 34 * refers to "void *".  The return type will be "void *".
 35 *
 36 * If type_id is a simple "int", then return type will be "int".
 37 *
 38 * @btf: struct btf object
 39 * @type_id: Find out the size of type_id. The type_id of the return
 40 *           type is set to *type_id.
 41 * @ret_size: It can be NULL.  If not NULL, the size of the return
 42 *            type is set to *ret_size.
 43 * Return: The btf_type (resolved to another type with size info if needed).
 44 *         NULL is returned if type_id itself does not have size info
 45 *         (e.g. void) or it cannot be resolved to another type that
 46 *         has size info.
 47 *         *type_id and *ret_size will not be changed in the
 48 *         NULL return case.
 49 */
 50const struct btf_type *btf_type_id_size(const struct btf *btf,
 51					u32 *type_id,
 52					u32 *ret_size);
 53
 54/*
 55 * Options to control show behaviour.
 56 *	- BTF_SHOW_COMPACT: no formatting around type information
 57 *	- BTF_SHOW_NONAME: no struct/union member names/types
 58 *	- BTF_SHOW_PTR_RAW: show raw (unobfuscated) pointer values;
 59 *	  equivalent to %px.
 60 *	- BTF_SHOW_ZERO: show zero-valued struct/union members; they
 61 *	  are not displayed by default
 62 *	- BTF_SHOW_UNSAFE: skip use of bpf_probe_read() to safely read
 63 *	  data before displaying it.
 64 */
 65#define BTF_SHOW_COMPACT	BTF_F_COMPACT
 66#define BTF_SHOW_NONAME		BTF_F_NONAME
 67#define BTF_SHOW_PTR_RAW	BTF_F_PTR_RAW
 68#define BTF_SHOW_ZERO		BTF_F_ZERO
 69#define BTF_SHOW_UNSAFE		(1ULL << 4)
 70
 71void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
 72		       struct seq_file *m);
 73int btf_type_seq_show_flags(const struct btf *btf, u32 type_id, void *obj,
 74			    struct seq_file *m, u64 flags);
 75
 76/*
 77 * Copy len bytes of string representation of obj of BTF type_id into buf.
 78 *
 79 * @btf: struct btf object
 80 * @type_id: type id of type obj points to
 81 * @obj: pointer to typed data
 82 * @buf: buffer to write to
 83 * @len: maximum length to write to buf
 84 * @flags: show options (see above)
 85 *
 86 * Return: length that would have been/was copied as per snprintf, or
 87 *	   negative error.
 88 */
 89int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
 90			   char *buf, int len, u64 flags);
 91
 92int btf_get_fd_by_id(u32 id);
 93u32 btf_obj_id(const struct btf *btf);
 94bool btf_is_kernel(const struct btf *btf);
 95bool btf_is_module(const struct btf *btf);
 96struct module *btf_try_get_module(const struct btf *btf);
 97u32 btf_nr_types(const struct btf *btf);
 98bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
 99			   const struct btf_member *m,
100			   u32 expected_offset, u32 expected_size);
101int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t);
102bool btf_type_is_void(const struct btf_type *t);
103s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind);
104const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
105					       u32 id, u32 *res_id);
106const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
107					    u32 id, u32 *res_id);
108const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
109						 u32 id, u32 *res_id);
110const struct btf_type *
111btf_resolve_size(const struct btf *btf, const struct btf_type *type,
112		 u32 *type_size);
113const char *btf_type_str(const struct btf_type *t);
114
115#define for_each_member(i, struct_type, member)			\
116	for (i = 0, member = btf_type_member(struct_type);	\
117	     i < btf_type_vlen(struct_type);			\
118	     i++, member++)
119
120#define for_each_vsi(i, datasec_type, member)			\
121	for (i = 0, member = btf_type_var_secinfo(datasec_type);	\
122	     i < btf_type_vlen(datasec_type);			\
123	     i++, member++)
124
125static inline bool btf_type_is_ptr(const struct btf_type *t)
126{
127	return BTF_INFO_KIND(t->info) == BTF_KIND_PTR;
128}
129
130static inline bool btf_type_is_int(const struct btf_type *t)
131{
132	return BTF_INFO_KIND(t->info) == BTF_KIND_INT;
133}
134
135static inline bool btf_type_is_small_int(const struct btf_type *t)
136{
137	return btf_type_is_int(t) && t->size <= sizeof(u64);
138}
139
140static inline bool btf_type_is_enum(const struct btf_type *t)
141{
142	return BTF_INFO_KIND(t->info) == BTF_KIND_ENUM;
143}
144
145static inline bool btf_type_is_scalar(const struct btf_type *t)
146{
147	return btf_type_is_int(t) || btf_type_is_enum(t);
148}
149
150static inline bool btf_type_is_typedef(const struct btf_type *t)
151{
152	return BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF;
153}
154
155static inline bool btf_type_is_func(const struct btf_type *t)
156{
157	return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC;
158}
159
160static inline bool btf_type_is_func_proto(const struct btf_type *t)
161{
162	return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC_PROTO;
163}
164
165static inline bool btf_type_is_var(const struct btf_type *t)
166{
167	return BTF_INFO_KIND(t->info) == BTF_KIND_VAR;
168}
169
170/* union is only a special case of struct:
171 * all its offsetof(member) == 0
172 */
173static inline bool btf_type_is_struct(const struct btf_type *t)
174{
175	u8 kind = BTF_INFO_KIND(t->info);
176
177	return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
178}
179
180static inline u16 btf_type_vlen(const struct btf_type *t)
181{
182	return BTF_INFO_VLEN(t->info);
183}
184
185static inline u16 btf_func_linkage(const struct btf_type *t)
186{
187	return BTF_INFO_VLEN(t->info);
188}
189
190static inline bool btf_type_kflag(const struct btf_type *t)
191{
192	return BTF_INFO_KFLAG(t->info);
193}
194
195static inline u32 btf_member_bit_offset(const struct btf_type *struct_type,
196					const struct btf_member *member)
197{
198	return btf_type_kflag(struct_type) ? BTF_MEMBER_BIT_OFFSET(member->offset)
199					   : member->offset;
200}
201
202static inline u32 btf_member_bitfield_size(const struct btf_type *struct_type,
203					   const struct btf_member *member)
204{
205	return btf_type_kflag(struct_type) ? BTF_MEMBER_BITFIELD_SIZE(member->offset)
206					   : 0;
207}
208
209static inline const struct btf_member *btf_type_member(const struct btf_type *t)
210{
211	return (const struct btf_member *)(t + 1);
212}
213
214static inline const struct btf_var_secinfo *btf_type_var_secinfo(
215		const struct btf_type *t)
216{
217	return (const struct btf_var_secinfo *)(t + 1);
218}
219
220#ifdef CONFIG_BPF_SYSCALL
221struct bpf_prog;
222
223const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id);
224const char *btf_name_by_offset(const struct btf *btf, u32 offset);
225struct btf *btf_parse_vmlinux(void);
226struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog);
227#else
228static inline const struct btf_type *btf_type_by_id(const struct btf *btf,
229						    u32 type_id)
230{
231	return NULL;
232}
233static inline const char *btf_name_by_offset(const struct btf *btf,
234					     u32 offset)
235{
236	return NULL;
237}
238#endif
239
240#endif