1 /* 2 * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com> 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 2 7 * of the License, or (at your option) any later version. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, see <http://www.gnu.org/licenses/>. 16 */ 17 18 #ifndef _ORC_TYPES_H 19 #define _ORC_TYPES_H 20 21 #include <linux/types.h> 22 #include <linux/compiler.h> 23 24 /* 25 * The ORC_REG_* registers are base registers which are used to find other 26 * registers on the stack. 27 * 28 * ORC_REG_PREV_SP, also known as DWARF Call Frame Address (CFA), is the 29 * address of the previous frame: the caller's SP before it called the current 30 * function. 31 * 32 * ORC_REG_UNDEFINED means the corresponding register's value didn't change in 33 * the current frame. 34 * 35 * The most commonly used base registers are SP and BP -- which the previous SP 36 * is usually based on -- and PREV_SP and UNDEFINED -- which the previous BP is 37 * usually based on. 38 * 39 * The rest of the base registers are needed for special cases like entry code 40 * and GCC realigned stacks. 41 */ 42 #define ORC_REG_UNDEFINED 0 43 #define ORC_REG_PREV_SP 1 44 #define ORC_REG_DX 2 45 #define ORC_REG_DI 3 46 #define ORC_REG_BP 4 47 #define ORC_REG_SP 5 48 #define ORC_REG_R10 6 49 #define ORC_REG_R13 7 50 #define ORC_REG_BP_INDIRECT 8 51 #define ORC_REG_SP_INDIRECT 9 52 #define ORC_REG_MAX 15 53 54 /* 55 * ORC_TYPE_CALL: Indicates that sp_reg+sp_offset resolves to PREV_SP (the 56 * caller's SP right before it made the call). Used for all callable 57 * functions, i.e. all C code and all callable asm functions. 58 * 59 * ORC_TYPE_REGS: Used in entry code to indicate that sp_reg+sp_offset points 60 * to a fully populated pt_regs from a syscall, interrupt, or exception. 61 * 62 * ORC_TYPE_REGS_IRET: Used in entry code to indicate that sp_reg+sp_offset 63 * points to the iret return frame. 64 * 65 * The UNWIND_HINT macros are used only for the unwind_hint struct. They 66 * aren't used in struct orc_entry due to size and complexity constraints. 67 * Objtool converts them to real types when it converts the hints to orc 68 * entries. 69 */ 70 #define ORC_TYPE_CALL 0 71 #define ORC_TYPE_REGS 1 72 #define ORC_TYPE_REGS_IRET 2 73 #define UNWIND_HINT_TYPE_SAVE 3 74 #define UNWIND_HINT_TYPE_RESTORE 4 75 76 #ifndef __ASSEMBLY__ 77 /* 78 * This struct is more or less a vastly simplified version of the DWARF Call 79 * Frame Information standard. It contains only the necessary parts of DWARF 80 * CFI, simplified for ease of access by the in-kernel unwinder. It tells the 81 * unwinder how to find the previous SP and BP (and sometimes entry regs) on 82 * the stack for a given code address. Each instance of the struct corresponds 83 * to one or more code locations. 84 */ 85 struct orc_entry { 86 s16 sp_offset; 87 s16 bp_offset; 88 unsigned sp_reg:4; 89 unsigned bp_reg:4; 90 unsigned type:2; 91 unsigned end:1; 92 } __packed; 93 94 /* 95 * This struct is used by asm and inline asm code to manually annotate the 96 * location of registers on the stack for the ORC unwinder. 97 * 98 * Type can be either ORC_TYPE_* or UNWIND_HINT_TYPE_*. 99 */ 100 struct unwind_hint { 101 u32 ip; 102 s16 sp_offset; 103 u8 sp_reg; 104 u8 type; 105 u8 end; 106 }; 107 #endif /* __ASSEMBLY__ */ 108 109 #endif /* _ORC_TYPES_H */ 110