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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  */
59 struct 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