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* Copyright (C) 2017 Josh Poimboeuf <>
* This program 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 2
* of the License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <>.
#ifndef _ORC_TYPES_H
#define _ORC_TYPES_H
#include <linux/types.h>
#include <linux/compiler.h>
* The ORC_REG_* registers are base registers which are used to find other
* registers on the stack.
* ORC_REG_PREV_SP, also known as DWARF Call Frame Address (CFA), is the
* address of the previous frame: the caller's SP before it called the current
* function.
* ORC_REG_UNDEFINED means the corresponding register's value didn't change in
* the current frame.
* The most commonly used base registers are SP and BP -- which the previous SP
* is usually based on -- and PREV_SP and UNDEFINED -- which the previous BP is
* usually based on.
* The rest of the base registers are needed for special cases like entry code
* and GCC realigned stacks.
#define ORC_REG_PREV_SP 1
#define ORC_REG_DX 2
#define ORC_REG_DI 3
#define ORC_REG_BP 4
#define ORC_REG_SP 5
#define ORC_REG_R10 6
#define ORC_REG_R13 7
#define ORC_REG_MAX 15
* ORC_TYPE_CALL: Indicates that sp_reg+sp_offset resolves to PREV_SP (the
* caller's SP right before it made the call). Used for all callable
* functions, i.e. all C code and all callable asm functions.
* ORC_TYPE_REGS: Used in entry code to indicate that sp_reg+sp_offset points
* to a fully populated pt_regs from a syscall, interrupt, or exception.
* ORC_TYPE_REGS_IRET: Used in entry code to indicate that sp_reg+sp_offset
* points to the iret return frame.
* The UNWIND_HINT macros are used only for the unwind_hint struct. They
* aren't used in struct orc_entry due to size and complexity constraints.
* Objtool converts them to real types when it converts the hints to orc
* entries.
#define ORC_TYPE_CALL 0
#define ORC_TYPE_REGS 1
#ifndef __ASSEMBLY__
* This struct is more or less a vastly simplified version of the DWARF Call
* Frame Information standard. It contains only the necessary parts of DWARF
* CFI, simplified for ease of access by the in-kernel unwinder. It tells the
* unwinder how to find the previous SP and BP (and sometimes entry regs) on
* the stack for a given code address. Each instance of the struct corresponds
* to one or more code locations.
struct orc_entry {
s16 sp_offset;
s16 bp_offset;
unsigned sp_reg:4;
unsigned bp_reg:4;
unsigned type:2;
} __packed;
* This struct is used by asm and inline asm code to manually annotate the
* location of registers on the stack for the ORC unwinder.
* Type can be either ORC_TYPE_* or UNWIND_HINT_TYPE_*.
struct unwind_hint {
u32 ip;
s16 sp_offset;
u8 sp_reg;
u8 type;
#endif /* __ASSEMBLY__ */
#endif /* _ORC_TYPES_H */