[thirdparty/gcc.git] / include / btf.h

/* 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_ */
Commit	Line	Data
b7e215a8	1	/* Declarations and definitions relating to the BPF Type Format (BTF).
7adcbafe	2	Copyright (C) 2021-2022 Free Software Foundation, Inc.
b7e215a8 IB	3
	4	This file is part of GCC.
	5
	6	GCC is free software; you can redistribute it and/or modify it
	7	under the terms of the GNU General Public License as published by
	8	the Free Software Foundation; either version 3, or (at your option)
	9	any later version.
	10
	11	GCC is distributed in the hope that it will be useful, but WITHOUT
	12	ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
	13	or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
	14	License for more details.
	15
	16	You should have received a copy of the GNU General Public License
	17	along with GCC; see the file COPYING3. If not see
	18	<http://www.gnu.org/licenses/>. */
	19
	20	/* This file is derived from the BTF specification described in the
	21	Linux kernel source tree (linux/Documentation/bpf/btf.rst). */
	22
	23	#ifndef _BTF_H_
	24	#define _BTF_H_
	25
	26	#include <stdint.h>
	27
	28	#ifdef __cplusplus
	29	extern "C"
	30	{
	31	#endif
	32
	33	/* BTF magic number to identify header, endianness. */
	34	#define BTF_MAGIC 0xeb9f
	35	/* Data format version number. */
	36	#define BTF_VERSION 1
	37
	38	struct btf_header
	39	{
	40	uint16_t magic; /* Magic number (BTF_MAGIC). */
	41	uint8_t version; /* Data format version (BTF_VERSION). */
	42	uint8_t flags; /* Flags. Currently unused. */
	43	uint32_t hdr_len; /* Length of this header (sizeof (struct btf_header)). */
	44
	45	/* Following offsets are relative to the end of this header. */
	46	uint32_t type_off; /* Offset of type section, in bytes. */
	47	uint32_t type_len; /* Length of type section, in bytes. */
	48	uint32_t str_off; /* Offset of string section, in bytes. */
	49	uint32_t str_len; /* Length of string section, in bytes. */
	50	};
	51
	52	/* Maximum type identifier. */
	53	#define BTF_MAX_TYPE 0x000fffff
	54	/* Maximum offset into the string section. */
	55	#define BTF_MAX_NAME_OFFSET 0x00ffffff
	56	/* Maximum number of struct, union, enum members or func args. */
	57	#define BTF_MAX_VLEN 0xffff
	58
	59	struct btf_type
	60	{
	61	uint32_t name_off; /* Offset in string section of type name. */
	62	uint32_t info; /* Encoded kind, variant length, kind flag:
	63	- bits 0-15: vlen
	64	- bits 16-23: unused
18d0fad7 DF	65	- bits 24-28: kind
18d0fad7 DF	66	- bits 29-30: unused
b7e215a8 IB	67	- bit 31: kind_flag
	68	See accessor macros below. */
	69
	70	/* SIZE is used by INT, ENUM, STRUCT, UNION, DATASEC kinds.
	71	TYPE is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT, FUNC,
	72	FUNC_PROTO and VAR kinds. */
	73	union
	74	{
	75	uint32_t size; /* Size of the entire type, in bytes. */
	76	uint32_t type; /* A type_id referring to another type. */
	77	};
	78	};
	79
	80	/* The folloing macros access the information encoded in btf_type.info. */
	81	/* Type kind. See below. */
18d0fad7	82	#define BTF_INFO_KIND(info) (((info) >> 24) & 0x1f)
b7e215a8 IB	83	/* Number of entries of variable length data following certain type kinds.
	84	For example, number of structure members, number of function parameters. */
	85	#define BTF_INFO_VLEN(info) ((info) & 0xffff)
	86	/* For BTF_KIND_FWD, 1 if forward to union, 0 if forward to struct.
	87	For BTF_KIND_STRUCT and BTF_KIND_UNION, 1 if the struct/union contains
	88	a bitfield. */
	89	#define BTF_INFO_KFLAG(info) ((info) >> 31)
	90
	91	/* Encoding for struct btf_type.info. */
	92	#define BTF_TYPE_INFO(kind, kflag, vlen) \
	93	((((kflag) ? 1 : 0 ) << 31) \| ((kind) << 24) \| ((vlen) & 0xffff))
	94
	95	#define BTF_KIND_UNKN 0 /* Unknown or invalid. */
	96	#define BTF_KIND_INT 1 /* Integer. */
	97	#define BTF_KIND_PTR 2 /* Pointer. */
	98	#define BTF_KIND_ARRAY 3 /* Array. */
	99	#define BTF_KIND_STRUCT 4 /* Struct. */
	100	#define BTF_KIND_UNION 5 /* Union. */
	101	#define BTF_KIND_ENUM 6 /* Enumeration. */
	102	#define BTF_KIND_FWD 7 /* Forward. */
	103	#define BTF_KIND_TYPEDEF 8 /* Typedef. */
	104	#define BTF_KIND_VOLATILE 9 /* Referenced type is volatile. */
	105	#define BTF_KIND_CONST 10 /* Referenced type is const. */
	106	#define BTF_KIND_RESTRICT 11 /* Restrict. */
	107	#define BTF_KIND_FUNC 12 /* Subprogram. */
	108	#define BTF_KIND_FUNC_PROTO 13 /* Function Prototype. */
	109	#define BTF_KIND_VAR 14 /* Variable. */
	110	#define BTF_KIND_DATASEC 15 /* Section such as .bss or .data. */
18d0fad7 DF	111	#define BTF_KIND_FLOAT 16 /* Floating point. */
18d0fad7 DF	112	#define BTF_KIND_MAX BTF_KIND_FLOAT
b7e215a8 IB	113	#define NR_BTF_KINDS (BTF_KIND_MAX + 1)
	114
	115	/* For some BTF_KINDs, struct btf_type is immediately followed by
	116	additional data describing the type. */
	117
	118	/* BTF_KIND_INT is followed by a 32-bit word, with the following
	119	bit arrangement. */
	120	#define BTF_INT_ENCODING(VAL) (((VAL) & 0x0f000000) >> 24)
	121	#define BTF_INT_OFFSET(VAL) (((VAL) & 0x00ff0000) >> 16)
	122	#define BTF_INT_BITS(VAL) ((VAL) & 0x000000ff)
	123
	124	#define BTF_INT_DATA(encoding, offset, bits) \
	125	((((encoding) & 0x0f) << 24) \| (((offset) & 0xff) << 16) \| ((bits) & 0xff))
	126
	127	/* BTF_INT_ENCODING holds the following attribute flags. */
	128	#define BTF_INT_SIGNED (1 << 0)
	129	#define BTF_INT_CHAR (1 << 1)
	130	#define BTF_INT_BOOL (1 << 2)
	131
	132	/* BTF_KIND_ENUM is followed by VLEN struct btf_enum entries,
	133	which describe the enumerators. Note that BTF currently only
	134	supports signed 32-bit enumerator values. */
	135	struct btf_enum
	136	{
	137	uint32_t name_off; /* Offset in string section of enumerator name. */
	138	int32_t val; /* Enumerator value. */
	139	};
	140
	141	/* BTF_KIND_ARRAY is followed by a single struct btf_array. */
	142	struct btf_array
	143	{
	144	uint32_t type; /* Type of array elements. */
	145	uint32_t index_type; /* Type of array index. */
	146	uint32_t nelems; /* Number of elements. 0 for unsized/variable length. */
	147	};
	148
	149	/* BTF_KIND_STRUCT and BTF_KIND_UNION are followed by VLEN
	150	struct btf_member. */
	151	struct btf_member
	152	{
	153	uint32_t name_off; /* Offset in string section of member name. */
	154	uint32_t type; /* Type of member. */
	155	uint32_t offset; /* If the type info kind_flag is set, this contains
	156	both the member bitfield size and bit offset,
	157	according to the macros below. If kind_flag is not
	158	set, offset contains only the bit offset (from the
	159	beginning of the struct). */
	160	};
	161
	162	/* If struct or union type info kind_flag is set, used to access member
	163	bitfield size from btf_member.offset. */
	164	#define BTF_MEMBER_BITFIELD_SIZE (val) ((val) >> 24)
	165	/* If struct or union type info kind_flag is set, used to access member
	166	bit offset from btf_member.offset. */
	167	#define BTF_MEMBER_BIT_OFFSET (val) ((val) & 0x00ffffff)
	168
	169	/* BTF_KIND_FUNC_PROTO is followed by VLEN struct btf_param entries, which
	170	describe the types of the function parameters. */
	171	struct btf_param
	172	{
	173	uint32_t name_off; /* Offset in string section of parameter name. */
	174	uint32_t type; /* Type of parameter. */
	175	};
	176
177	/* BTF_KIND_VAR is followed by a single struct btf_var, which describes
178	information about the variable. */
179	struct btf_var
180	{
181	uint32_t linkage; /* Currently only 0=static or 1=global. */
182	};
183
184	/* BTF_KIND_DATASEC is followed by VLEN struct btf_var_secinfo entries,
185	which describe all BTF_KIND_VAR types contained in the section. */
186	struct btf_var_secinfo
187	{
188	uint32_t type; /* Type of variable. */
189	uint32_t offset; /* In-section offset of variable (in bytes). */
190	uint32_t size; /* Size (in bytes) of variable. */
191	};
192
193	#ifdef __cplusplus
194	}
195	#endif
196
197	#endif /* _BTF_H_ */