| /* Declarations and definitions relating to the BPF Type Format (BTF). |
| Copyright (C) 2021-2022 Free Software Foundation, Inc. |
| |
| This file is part of GCC. |
| |
| GCC is free software; you can redistribute it and/or modify it |
| under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3, or (at your option) |
| any later version. |
| |
| GCC is distributed in the hope that it will be useful, but WITHOUT |
| ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
| or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public |
| License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GCC; see the file COPYING3. If not see |
| <http://www.gnu.org/licenses/>. */ |
| |
| /* This file is derived from the BTF specification described in the |
| Linux kernel source tree (linux/Documentation/bpf/btf.rst). */ |
| |
| #ifndef _BTF_H_ |
| #define _BTF_H_ |
| |
| #include <stdint.h> |
| |
| #ifdef __cplusplus |
| extern "C" |
| { |
| #endif |
| |
| /* BTF magic number to identify header, endianness. */ |
| #define BTF_MAGIC 0xeb9f |
| /* Data format version number. */ |
| #define BTF_VERSION 1 |
| |
| struct btf_header |
| { |
| uint16_t magic; /* Magic number (BTF_MAGIC). */ |
| uint8_t version; /* Data format version (BTF_VERSION). */ |
| uint8_t flags; /* Flags. Currently unused. */ |
| uint32_t hdr_len; /* Length of this header (sizeof (struct btf_header)). */ |
| |
| /* Following offsets are relative to the end of this header. */ |
| uint32_t type_off; /* Offset of type section, in bytes. */ |
| uint32_t type_len; /* Length of type section, in bytes. */ |
| uint32_t str_off; /* Offset of string section, in bytes. */ |
| uint32_t str_len; /* Length of string section, in bytes. */ |
| }; |
| |
| /* Maximum type identifier. */ |
| #define BTF_MAX_TYPE 0x000fffff |
| /* Maximum offset into the string section. */ |
| #define BTF_MAX_NAME_OFFSET 0x00ffffff |
| /* Maximum number of struct, union, enum members or func args. */ |
| #define BTF_MAX_VLEN 0xffff |
| |
| struct btf_type |
| { |
| uint32_t name_off; /* Offset in string section of type name. */ |
| uint32_t info; /* Encoded kind, variant length, kind flag: |
| - bits 0-15: vlen |
| - bits 16-23: unused |
| - bits 24-28: kind |
| - bits 29-30: unused |
| - bit 31: kind_flag |
| See accessor macros below. */ |
| |
| /* SIZE is used by INT, ENUM, STRUCT, UNION, DATASEC kinds. |
| TYPE is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT, FUNC, |
| FUNC_PROTO and VAR kinds. */ |
| union |
| { |
| uint32_t size; /* Size of the entire type, in bytes. */ |
| uint32_t type; /* A type_id referring to another type. */ |
| }; |
| }; |
| |
| /* The folloing macros access the information encoded in btf_type.info. */ |
| /* Type kind. See below. */ |
| #define BTF_INFO_KIND(info) (((info) >> 24) & 0x1f) |
| /* Number of entries of variable length data following certain type kinds. |
| For example, number of structure members, number of function parameters. */ |
| #define BTF_INFO_VLEN(info) ((info) & 0xffff) |
| /* For BTF_KIND_FWD, 1 if forward to union, 0 if forward to struct. |
| For BTF_KIND_STRUCT and BTF_KIND_UNION, 1 if the struct/union contains |
| a bitfield. */ |
| #define BTF_INFO_KFLAG(info) ((info) >> 31) |
| |
| /* Encoding for struct btf_type.info. */ |
| #define BTF_TYPE_INFO(kind, kflag, vlen) \ |
| ((((kflag) ? 1 : 0 ) << 31) | ((kind) << 24) | ((vlen) & 0xffff)) |
| |
| #define BTF_KIND_UNKN 0 /* Unknown or invalid. */ |
| #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 /* Referenced type is volatile. */ |
| #define BTF_KIND_CONST 10 /* Referenced type is const. */ |
| #define BTF_KIND_RESTRICT 11 /* Restrict. */ |
| #define BTF_KIND_FUNC 12 /* Subprogram. */ |
| #define BTF_KIND_FUNC_PROTO 13 /* Function Prototype. */ |
| #define BTF_KIND_VAR 14 /* Variable. */ |
| #define BTF_KIND_DATASEC 15 /* Section such as .bss or .data. */ |
| #define BTF_KIND_FLOAT 16 /* Floating point. */ |
| #define BTF_KIND_MAX BTF_KIND_FLOAT |
| #define NR_BTF_KINDS (BTF_KIND_MAX + 1) |
| |
| /* For some BTF_KINDs, struct btf_type is immediately followed by |
| additional data describing the type. */ |
| |
| /* BTF_KIND_INT is followed by a 32-bit word, with the following |
| bit arrangement. */ |
| #define BTF_INT_ENCODING(VAL) (((VAL) & 0x0f000000) >> 24) |
| #define BTF_INT_OFFSET(VAL) (((VAL) & 0x00ff0000) >> 16) |
| #define BTF_INT_BITS(VAL) ((VAL) & 0x000000ff) |
| |
| #define BTF_INT_DATA(encoding, offset, bits) \ |
| ((((encoding) & 0x0f) << 24) | (((offset) & 0xff) << 16) | ((bits) & 0xff)) |
| |
| /* BTF_INT_ENCODING holds the following attribute flags. */ |
| #define BTF_INT_SIGNED (1 << 0) |
| #define BTF_INT_CHAR (1 << 1) |
| #define BTF_INT_BOOL (1 << 2) |
| |
| /* BTF_KIND_ENUM is followed by VLEN struct btf_enum entries, |
| which describe the enumerators. Note that BTF currently only |
| supports signed 32-bit enumerator values. */ |
| struct btf_enum |
| { |
| uint32_t name_off; /* Offset in string section of enumerator name. */ |
| int32_t val; /* Enumerator value. */ |
| }; |
| |
| /* BTF_KIND_ARRAY is followed by a single struct btf_array. */ |
| struct btf_array |
| { |
| uint32_t type; /* Type of array elements. */ |
| uint32_t index_type; /* Type of array index. */ |
| uint32_t nelems; /* Number of elements. 0 for unsized/variable length. */ |
| }; |
| |
| /* BTF_KIND_STRUCT and BTF_KIND_UNION are followed by VLEN |
| struct btf_member. */ |
| struct btf_member |
| { |
| uint32_t name_off; /* Offset in string section of member name. */ |
| uint32_t type; /* Type of member. */ |
| uint32_t offset; /* If the type info kind_flag is set, this contains |
| both the member bitfield size and bit offset, |
| according to the macros below. If kind_flag is not |
| set, offset contains only the bit offset (from the |
| beginning of the struct). */ |
| }; |
| |
| /* If struct or union type info kind_flag is set, used to access member |
| bitfield size from btf_member.offset. */ |
| #define BTF_MEMBER_BITFIELD_SIZE (val) ((val) >> 24) |
| /* If struct or union type info kind_flag is set, used to access member |
| bit offset from btf_member.offset. */ |
| #define BTF_MEMBER_BIT_OFFSET (val) ((val) & 0x00ffffff) |
| |
| /* BTF_KIND_FUNC_PROTO is followed by VLEN struct btf_param entries, which |
| describe the types of the function parameters. */ |
| struct btf_param |
| { |
| uint32_t name_off; /* Offset in string section of parameter name. */ |
| uint32_t type; /* Type of parameter. */ |
| }; |
| |
| /* BTF_KIND_VAR is followed by a single struct btf_var, which describes |
| information about the variable. */ |
| struct btf_var |
| { |
| uint32_t linkage; /* Currently only 0=static or 1=global. */ |
| }; |
| |
| /* BTF_KIND_DATASEC is followed by VLEN struct btf_var_secinfo entries, |
| which describe all BTF_KIND_VAR types contained in the section. */ |
| struct btf_var_secinfo |
| { |
| uint32_t type; /* Type of variable. */ |
| uint32_t offset; /* In-section offset of variable (in bytes). */ |
| uint32_t size; /* Size (in bytes) of variable. */ |
| }; |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| #endif /* _BTF_H_ */ |