/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
/* Copyright (c) 2018 Facebook */
#ifndef _UAPI__LINUX_BTF_H__
#define _UAPI__LINUX_BTF_H__
#include <linux/types.h>
#define BTF_MAGIC 0xeB9F
#define BTF_VERSION 1
struct btf_header {
__u16 magic;
__u8 version;
__u8 flags;
__u32 hdr_len;
/* All offsets are in bytes relative to the end of this header */
__u32 type_off; /* offset of type section */
__u32 type_len; /* length of type section */
__u32 str_off; /* offset of string section */
__u32 str_len; /* length of string section */
};
/* Max # of type identifier */
#define BTF_MAX_TYPE 0x000fffff
/* Max offset into the string section */
#define BTF_MAX_NAME_OFFSET 0x00ffffff
/* Max # of struct/union/enum members or func args */
#define BTF_MAX_VLEN 0xffff
struct btf_type {
__u32 name_off;
/* "info" bits arrangement
* bits 0-15: vlen (e.g. # of struct's members)
* bits 16-23: unused
* bits 24-28: kind (e.g. int, ptr, array...etc)
* bits 29-30: unused
* bit 31: kind_flag, currently used by
* struct, union, enum, fwd and enum64
*/
__u32 info;
/* "size" is used by INT, ENUM, STRUCT, UNION, DATASEC and ENUM64.
* "size" tells the size of the type it is describing.
*
* "type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT,
* FUNC, FUNC_PROTO, VAR, DECL_TAG and TYPE_TAG.
* "type" is a type_id referring to another type.
*/
union {
__u32 size;
__u32 type;
};
};
#define BTF_INFO_KIND(info) (((info) >> 24) & 0x1f)
#define BTF_INFO_VLEN(info) ((info) & 0xffff)
#define BTF_INFO_KFLAG(info) ((info) >> 31)
enum {
BTF_KIND_UNKN = 0, /* Unknown */
BTF_KIND_INT = 1, /* Integer */
BTF_KIND_PTR = 2, /* Pointer */
BTF_KIND_ARRAY = 3, /* Array */
BTF_KIND_STRUCT = 4, /* Struct */
BTF_KIND_UNION = 5, /* Union */
BTF_KIND_ENUM = 6, /* Enumeration up to 32-bit values */
BTF_KIND_FWD = 7, /* Forward */
BTF_KIND_TYPEDEF = 8, /* Typedef */
BTF_KIND_VOLATILE = 9, /* Volatile */
BTF_KIND_CONST = 10, /* Const */
BTF_KIND_RESTRICT = 11, /* Restrict */
BTF_KIND_FUNC = 12, /* Function */
BTF_KIND_FUNC_PROTO = 13, /* Function Proto */
BTF_KIND_VAR = 14, /* Variable */
BTF_KIND_DATASEC = 15, /* Section */
BTF_KIND_FLOAT = 16, /* Floating point */
BTF_KIND_DECL_TAG = 17, /* Decl Tag */
BTF_KIND_TYPE_TAG = 18, /* Type Tag */
BTF_KIND_ENUM64 = 19, /* Enumeration up to 64-bit values */
NR_BTF_KINDS,
BTF_KIND_MAX = NR_BTF_KINDS - 1,
};
/* For some specific BTF_KIND, "struct btf_type" is immediately
* followed by extra data.
*/
/* BTF_KIND_INT is followed by a u32 and the following
* is the 32 bits arrangement:
*/
#define BTF_INT_ENCODING(VAL) (((VAL) & 0x0f000000) >> 24)
#define BTF_INT_OFFSET(VAL) (((VAL) & 0x00ff0000) >> 16)
#define BTF_INT_BITS(VAL) ((VAL) & 0x000000ff)
/* Attributes stored in the BTF_INT_ENCODING */
#define BTF_INT_SIGNED (1 << 0)
#define BTF_INT_CHAR (1 << 1)
#define BTF_INT_BOOL (1 << 2)
/* BTF_KIND_ENUM is followed by multiple "struct btf_enum".
* The exact number of btf_enum is stored in the vlen (of the
* info in "struct btf_type").
*/
struct btf_enum {
__u32 name_off;
__s32 val;
};
/* BTF_KIND_ARRAY is followed by one "struct btf_array" */
struct btf_array {
__u32 type;
__u32 index_type;
__u32 nelems;
};
/* BTF_KIND_STRUCT and BTF_KIND_UNION are followed
* by multiple "struct btf_member". The exact number
* of btf_member is stored in the vlen (of the info in
* "struct btf_type").
*/
struct btf_member {
__u32 name_off;
__u32 type;
/* If the type info kind_flag is set, the btf_member offset
* contains both member bitfield size and bit offset. The
* bitfield size is set for bitfield members. If the type
* info kind_flag is not set, the offset contains only bit
* offset.
*/
__u32 offset;
};
/* If the struct/union type info kind_flag is set, the
* following two macros are used to access bitfield_size
* and bit_offset from btf_member.offset.
*/
#define BTF_MEMBER_BITFIELD_SIZE(val) ((val) >> 24)
#define BTF_MEMBER_BIT_OFFSET(val) ((val) & 0xffffff)
/* BTF_KIND_FUNC_PROTO is followed by multiple "struct btf_param".
* The exact number of btf_param is stored in the vlen (of the
* info in "struct btf_type").
*/
struct btf_param {
__u32 name_off;
__u32 type;
};
enum {
BTF_VAR_STATIC = 0,
BTF_VAR_GLOBAL_ALLOCATED = 1,
BTF_VAR_GLOBAL_EXTERN = 2,
};
enum btf_func_linkage {
BTF_FUNC_STATIC = 0,
BTF_FUNC_GLOBAL = 1,
BTF_FUNC_EXTERN = 2,
};
/* BTF_KIND_VAR is followed by a single "struct btf_var" to describe
* additional information related to the variable such as its linkage.
*/
struct btf_var {
__u32 linkage;
};
/* BTF_KIND_DATASEC is followed by multiple "struct btf_var_secinfo"
* to describe all BTF_KIND_VAR types it contains along with it's
* in-section offset as well as size.
*/
struct btf_var_secinfo {
__u32 type;
__u32 offset;
__u32 size;
};
/* BTF_KIND_DECL_TAG is followed by a single "struct btf_decl_tag" to describe
* additional information related to the tag applied location.
* If component_idx == -1, the tag is applied to a struct, union,
* variable or function. Otherwise, it is applied to a struct/union
* member or a func argument, and component_idx indicates which member
* or argument (0 ... vlen-1).
*/
struct btf_decl_tag {
__s32 component_idx;
};
/* BTF_KIND_ENUM64 is followed by multiple "struct btf_enum64".
* The exact number of btf_enum64 is stored in the vlen (of the
* info in "struct btf_type").
*/
struct btf_enum64 {
__u32 name_off;
__u32 val_lo32;
__u32 val_hi32;
};
#endif /* _UAPI__LINUX_BTF_H__ */
Codebase Browser
linux