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alistair23-linux/include/uapi/linux/btf.h

131 lines
3.6 KiB
C

/* 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_MAGIC_SWAP 0x9FeB
#define BTF_VERSION 1
#define BTF_FLAGS_COMPR 0x01
struct btf_header {
__u16 magic;
__u8 version;
__u8 flags;
__u32 parent_label;
__u32 parent_name;
/* All offsets are in bytes relative to the end of this header */
__u32 label_off; /* offset of label section */
__u32 object_off; /* offset of data object section*/
__u32 func_off; /* offset of function section */
__u32 type_off; /* offset 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 0x7fffffff
/* Max offset into the string section */
#define BTF_MAX_NAME_OFFSET 0x7fffffff
/* Max # of struct/union/enum members or func args */
#define BTF_MAX_VLEN 0xffff
/* The type id is referring to a parent BTF */
#define BTF_TYPE_PARENT(id) (((id) >> 31) & 0x1)
#define BTF_TYPE_ID(id) ((id) & BTF_MAX_TYPE)
/* String is in the ELF string section */
#define BTF_STR_TBL_ELF_ID(ref) (((ref) >> 31) & 0x1)
#define BTF_STR_OFFSET(ref) ((ref) & BTF_MAX_NAME_OFFSET)
struct btf_type {
__u32 name;
/* "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
* bits 31: root
*/
__u32 info;
/* "size" is used by INT, ENUM, STRUCT and UNION.
* "size" tells the size of the type it is describing.
*
* "type" is used by PTR, TYPEDEF, VOLATILE, CONST and RESTRICT.
* "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_ISROOT(info) (!!(((info) >> 24) & 0x80))
#define BTF_INFO_VLEN(info) ((info) & 0xffff)
#define BTF_KIND_UNKN 0 /* Unknown */
#define BTF_KIND_INT 1 /* Integer */
#define BTF_KIND_PTR 2 /* Pointer */
#define BTF_KIND_ARRAY 3 /* Array */
#define BTF_KIND_STRUCT 4 /* Struct */
#define BTF_KIND_UNION 5 /* Union */
#define BTF_KIND_ENUM 6 /* Enumeration */
#define BTF_KIND_FWD 7 /* Forward */
#define BTF_KIND_TYPEDEF 8 /* Typedef */
#define BTF_KIND_VOLATILE 9 /* Volatile */
#define BTF_KIND_CONST 10 /* Const */
#define BTF_KIND_RESTRICT 11 /* Restrict */
#define BTF_KIND_MAX 11
#define NR_BTF_KINDS 12
/* 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) & 0xff000000) >> 24)
#define BTF_INT_OFFSET(VAL) (((VAL & 0x00ff0000)) >> 16)
#define BTF_INT_BITS(VAL) ((VAL) & 0x0000ffff)
/* Attributes stored in the BTF_INT_ENCODING */
#define BTF_INT_SIGNED 0x1
#define BTF_INT_CHAR 0x2
#define BTF_INT_BOOL 0x4
#define BTF_INT_VARARGS 0x8
/* 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;
__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;
__u32 type;
__u32 offset; /* offset in bits */
};
#endif /* _UAPI__LINUX_BTF_H__ */