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https://github.com/brain-hackers/linux-brain.git
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f063c889c9
This adds the BTF specification and UAPI bits for supporting BTF Var
and DataSec kinds. This is following LLVM upstream commit ac4082b77e07
("[BPF] Add BTF Var and DataSec Support") which has been merged recently.
Var itself is for describing a global variable and DataSec to describe
ELF sections e.g. data/bss/rodata sections that hold one or multiple
global variables.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
166 lines
4.5 KiB
C
166 lines
4.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
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/* Copyright (c) 2018 Facebook */
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#ifndef _UAPI__LINUX_BTF_H__
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#define _UAPI__LINUX_BTF_H__
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#include <linux/types.h>
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#define BTF_MAGIC 0xeB9F
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#define BTF_VERSION 1
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struct btf_header {
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__u16 magic;
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__u8 version;
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__u8 flags;
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__u32 hdr_len;
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/* All offsets are in bytes relative to the end of this header */
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__u32 type_off; /* offset of type section */
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__u32 type_len; /* length of type section */
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__u32 str_off; /* offset of string section */
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__u32 str_len; /* length of string section */
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};
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/* Max # of type identifier */
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#define BTF_MAX_TYPE 0x0000ffff
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/* Max offset into the string section */
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#define BTF_MAX_NAME_OFFSET 0x0000ffff
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/* Max # of struct/union/enum members or func args */
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#define BTF_MAX_VLEN 0xffff
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struct btf_type {
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__u32 name_off;
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/* "info" bits arrangement
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* bits 0-15: vlen (e.g. # of struct's members)
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* bits 16-23: unused
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* bits 24-27: kind (e.g. int, ptr, array...etc)
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* bits 28-30: unused
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* bit 31: kind_flag, currently used by
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* struct, union and fwd
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*/
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__u32 info;
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/* "size" is used by INT, ENUM, STRUCT, UNION and DATASEC.
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* "size" tells the size of the type it is describing.
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*
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* "type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT,
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* FUNC, FUNC_PROTO and VAR.
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* "type" is a type_id referring to another type.
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*/
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union {
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__u32 size;
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__u32 type;
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};
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};
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#define BTF_INFO_KIND(info) (((info) >> 24) & 0x0f)
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#define BTF_INFO_VLEN(info) ((info) & 0xffff)
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#define BTF_INFO_KFLAG(info) ((info) >> 31)
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#define BTF_KIND_UNKN 0 /* Unknown */
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#define BTF_KIND_INT 1 /* Integer */
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#define BTF_KIND_PTR 2 /* Pointer */
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#define BTF_KIND_ARRAY 3 /* Array */
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#define BTF_KIND_STRUCT 4 /* Struct */
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#define BTF_KIND_UNION 5 /* Union */
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#define BTF_KIND_ENUM 6 /* Enumeration */
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#define BTF_KIND_FWD 7 /* Forward */
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#define BTF_KIND_TYPEDEF 8 /* Typedef */
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#define BTF_KIND_VOLATILE 9 /* Volatile */
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#define BTF_KIND_CONST 10 /* Const */
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#define BTF_KIND_RESTRICT 11 /* Restrict */
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#define BTF_KIND_FUNC 12 /* Function */
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#define BTF_KIND_FUNC_PROTO 13 /* Function Proto */
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#define BTF_KIND_VAR 14 /* Variable */
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#define BTF_KIND_DATASEC 15 /* Section */
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#define BTF_KIND_MAX BTF_KIND_DATASEC
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#define NR_BTF_KINDS (BTF_KIND_MAX + 1)
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/* For some specific BTF_KIND, "struct btf_type" is immediately
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* followed by extra data.
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*/
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/* BTF_KIND_INT is followed by a u32 and the following
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* is the 32 bits arrangement:
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*/
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#define BTF_INT_ENCODING(VAL) (((VAL) & 0x0f000000) >> 24)
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#define BTF_INT_OFFSET(VAL) (((VAL & 0x00ff0000)) >> 16)
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#define BTF_INT_BITS(VAL) ((VAL) & 0x000000ff)
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/* Attributes stored in the BTF_INT_ENCODING */
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#define BTF_INT_SIGNED (1 << 0)
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#define BTF_INT_CHAR (1 << 1)
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#define BTF_INT_BOOL (1 << 2)
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/* BTF_KIND_ENUM is followed by multiple "struct btf_enum".
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* The exact number of btf_enum is stored in the vlen (of the
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* info in "struct btf_type").
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*/
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struct btf_enum {
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__u32 name_off;
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__s32 val;
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};
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/* BTF_KIND_ARRAY is followed by one "struct btf_array" */
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struct btf_array {
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__u32 type;
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__u32 index_type;
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__u32 nelems;
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};
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/* BTF_KIND_STRUCT and BTF_KIND_UNION are followed
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* by multiple "struct btf_member". The exact number
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* of btf_member is stored in the vlen (of the info in
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* "struct btf_type").
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*/
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struct btf_member {
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__u32 name_off;
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__u32 type;
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/* If the type info kind_flag is set, the btf_member offset
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* contains both member bitfield size and bit offset. The
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* bitfield size is set for bitfield members. If the type
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* info kind_flag is not set, the offset contains only bit
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* offset.
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*/
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__u32 offset;
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};
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/* If the struct/union type info kind_flag is set, the
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* following two macros are used to access bitfield_size
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* and bit_offset from btf_member.offset.
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*/
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#define BTF_MEMBER_BITFIELD_SIZE(val) ((val) >> 24)
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#define BTF_MEMBER_BIT_OFFSET(val) ((val) & 0xffffff)
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/* BTF_KIND_FUNC_PROTO is followed by multiple "struct btf_param".
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* The exact number of btf_param is stored in the vlen (of the
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* info in "struct btf_type").
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*/
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struct btf_param {
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__u32 name_off;
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__u32 type;
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};
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enum {
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BTF_VAR_STATIC = 0,
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BTF_VAR_GLOBAL_ALLOCATED,
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};
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/* BTF_KIND_VAR is followed by a single "struct btf_var" to describe
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* additional information related to the variable such as its linkage.
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*/
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struct btf_var {
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__u32 linkage;
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};
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/* BTF_KIND_DATASEC is followed by multiple "struct btf_var_secinfo"
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* to describe all BTF_KIND_VAR types it contains along with it's
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* in-section offset as well as size.
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*/
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struct btf_var_secinfo {
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__u32 type;
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__u32 offset;
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__u32 size;
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};
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#endif /* _UAPI__LINUX_BTF_H__ */
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