1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
4 */
5
6#ifndef _ORC_TYPES_H
7#define _ORC_TYPES_H
8
9#include <linux/types.h>
10#include <linux/compiler.h>
11
12/*
13 * The ORC_REG_* registers are base registers which are used to find other
14 * registers on the stack.
15 *
16 * ORC_REG_PREV_SP, also known as DWARF Call Frame Address (CFA), is the
17 * address of the previous frame: the caller's SP before it called the current
18 * function.
19 *
20 * ORC_REG_UNDEFINED means the corresponding register's value didn't change in
21 * the current frame.
22 *
23 * The most commonly used base registers are SP and BP -- which the previous SP
24 * is usually based on -- and PREV_SP and UNDEFINED -- which the previous BP is
25 * usually based on.
26 *
27 * The rest of the base registers are needed for special cases like entry code
28 * and GCC realigned stacks.
29 */
30#define ORC_REG_UNDEFINED		0
31#define ORC_REG_PREV_SP			1
32#define ORC_REG_DX			2
33#define ORC_REG_DI			3
34#define ORC_REG_BP			4
35#define ORC_REG_SP			5
36#define ORC_REG_R10			6
37#define ORC_REG_R13			7
38#define ORC_REG_BP_INDIRECT		8
39#define ORC_REG_SP_INDIRECT		9
40#define ORC_REG_MAX			15
41
42#define ORC_TYPE_UNDEFINED		0
43#define ORC_TYPE_END_OF_STACK		1
44#define ORC_TYPE_CALL			2
45#define ORC_TYPE_REGS			3
46#define ORC_TYPE_REGS_PARTIAL		4
47
48#ifndef __ASSEMBLY__
49#include <asm/byteorder.h>
50
51/*
52 * This struct is more or less a vastly simplified version of the DWARF Call
53 * Frame Information standard.  It contains only the necessary parts of DWARF
54 * CFI, simplified for ease of access by the in-kernel unwinder.  It tells the
55 * unwinder how to find the previous SP and BP (and sometimes entry regs) on
56 * the stack for a given code address.  Each instance of the struct corresponds
57 * to one or more code locations.
58 */
59struct orc_entry {
60	s16		sp_offset;
61	s16		bp_offset;
62#if defined(__LITTLE_ENDIAN_BITFIELD)
63	unsigned	sp_reg:4;
64	unsigned	bp_reg:4;
65	unsigned	type:3;
66	unsigned	signal:1;
67#elif defined(__BIG_ENDIAN_BITFIELD)
68	unsigned	bp_reg:4;
69	unsigned	sp_reg:4;
70	unsigned	unused:4;
71	unsigned	signal:1;
72	unsigned	type:3;
73#endif
74} __packed;
75
76#endif /* __ASSEMBLY__ */
77
78#endif /* _ORC_TYPES_H */
79