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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* 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
* 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 this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
#ifndef BACKENDS_ELF_H
#define BACKENDS_ELF_H
#include "common/scummsys.h"
#if defined(DYNAMIC_MODULES) && defined(USE_ELF_LOADER)
/**
* ELF stuff:
* The contents of this file were gathered mainly from the SYSTEM V APPLICATION BINARY INTERFACE.
* Processor-specific things were garnered from processor-specific supplements to the abi.
*/
typedef uint16 Elf32_Half, Elf32_Section;
typedef uint32 Elf32_Word, Elf32_Addr, Elf32_Off;
typedef int32 Elf32_Sword;
typedef Elf32_Half Elf32_Versym;
#define EI_NIDENT (16)
#define SELFMAG 4
/* ELF File format structures. Look up ELF structure for more details */
// ELF header (contains info about the file)
typedef struct {
byte e_ident[EI_NIDENT]; /* Magic number and other info */
Elf32_Half e_type; /* Object file type */
Elf32_Half e_machine; /* Architecture */
Elf32_Word e_version; /* Object file version */
Elf32_Addr e_entry; /* Entry point virtual address */
Elf32_Off e_phoff; /* Program header table file offset */
Elf32_Off e_shoff; /* Section header table file offset */
Elf32_Word e_flags; /* Processor-specific flags */
Elf32_Half e_ehsize; /* ELF header size in bytes */
Elf32_Half e_phentsize; /* Program header table entry size */
Elf32_Half e_phnum; /* Program header table entry count */
Elf32_Half e_shentsize; /* Section header table entry size */
Elf32_Half e_shnum; /* Section header table entry count */
Elf32_Half e_shstrndx; /* Section header string table index */
} Elf32_Ehdr;
// Should be in e_ident
#define ELFMAG "\177ELF" /* ELF Magic number */
#define EI_CLASS 4 /* File class byte index */
#define ELFCLASS32 1 /* 32-bit objects */
#define EI_DATA 5 /* Data encoding byte index */
#define ELFDATA2LSB 1 /* 2's complement, little endian */
#define ELFDATA2MSB 2 /* 2's complement, big endian */
#define EI_VERSION 6
#define EV_CURRENT 1 /* Current version */
// e_type values
#define ET_NONE 0 /* no file type */
#define ET_REL 1 /* relocatable */
#define ET_EXEC 2 /* executable */
#define ET_DYN 3 /* shared object */
#define ET_CORE 4 /* core file */
// e_machine values
#define EM_MIPS 8
#define EM_PPC 20
#define EM_ARM 40
#define EM_SH 42
// Program header (contains info about segment)
typedef struct {
Elf32_Word p_type; /* Segment type */
Elf32_Off p_offset; /* Segment file offset */
Elf32_Addr p_vaddr; /* Segment virtual address */
Elf32_Addr p_paddr; /* Segment physical address */
Elf32_Word p_filesz; /* Segment size in file */
Elf32_Word p_memsz; /* Segment size in memory */
Elf32_Word p_flags; /* Segment flags */
Elf32_Word p_align; /* Segment alignment */
} Elf32_Phdr;
// p_type values
#define PT_NULL 0 /* ignored */
#define PT_LOAD 1 /* loadable segment */
#define PT_DYNAMIC 2 /* dynamic linking info */
#define PT_INTERP 3 /* info about interpreter */
#define PT_NOTE 4 /* note segment */
#define PT_SHLIB 5 /* reserved */
#define PT_PHDR 6 /* Program header table */
#define PT_MIPS_REGINFO 0x70000000 /* Register usage info for MIPS */
#define PT_ARM_ARCHEXT 0x70000000 /* Platform architecture compatibility info for ARM */
#define PT_ARM_EXIDX 0x70000001 /* Exception unwind tables for ARM */
// p_flags value
#define PF_X 1 /* execute */
#define PF_W 2 /* write */
#define PF_R 4 /* read */
// Section header (contains info about section)
typedef struct {
Elf32_Word sh_name; /* Section name (string tbl index) */
Elf32_Word sh_type; /* Section type */
Elf32_Word sh_flags; /* Section flags */
Elf32_Addr sh_addr; /* Section virtual addr at execution */
Elf32_Off sh_offset; /* Section file offset */
Elf32_Word sh_size; /* Section size in bytes */
Elf32_Word sh_link; /* Link to another section */
Elf32_Word sh_info; /* Additional section information */
Elf32_Word sh_addralign; /* Section alignment */
Elf32_Word sh_entsize; /* Entry size if section holds table */
} Elf32_Shdr;
// sh_type values
#define SHT_NULL 0 /* Inactive section */
#define SHT_PROGBITS 1 /* Proprietary */
#define SHT_SYMTAB 2 /* Symbol table */
#define SHT_STRTAB 3 /* String table */
#define SHT_RELA 4 /* Relocation entries with addend */
#define SHT_HASH 5 /* Symbol hash table */
#define SHT_DYNAMIC 6 /* Info for dynamic linking */
#define SHT_NOTE 7 /* Note section */
#define SHT_NOBITS 8 /* Occupies no space */
#define SHT_REL 9 /* Relocation entries without addend */
#define SHT_SHLIB 10 /* Reserved */
#define SHT_DYNSYM 11 /* Minimal set of dynamic linking symbols */
#define SHT_MIPS_LIBLSIT 0x70000000 /* Info about dynamic shared object libs for MIPS*/
#define SHT_MIPS_CONFLICT 0x70000002 /* Conflicts btw executables and shared objects for MIPS */
#define SHT_MIPS_GPTAB 0x70000003 /* Global pointer table for MIPS*/
#define SHT_ARM_EXIDX 0x70000001 /* Exception Index table for ARM*/
#define SHT_ARM_PREEMPTMAP 0x70000002 /* BPABI DLL dynamic linking pre-emption map for ARM */
#define SHT_ARM_ATTRIBUTES 0x70000003 /* Object file compatibility attributes for ARM*/
// sh_flags values
#define SHF_WRITE 0 /* writable section */
#define SHF_ALLOC 2 /* section occupies memory */
#define SHF_EXECINSTR 4 /* machine instructions */
#define SHF_MIPS_GPREL 0x10000000 /* Must be made part of global data area for MIPS */
// Symbol entry (contain info about a symbol)
typedef struct {
Elf32_Word st_name; /* Symbol name (string tbl index) */
Elf32_Addr st_value; /* Symbol value */
Elf32_Word st_size; /* Symbol size */
byte st_info; /* Symbol type and binding */
byte st_other; /* Symbol visibility */
Elf32_Section st_shndx; /* Section index */
} Elf32_Sym;
// Extract from the st_info
#define SYM_TYPE(x) ((x) & 0xf)
#define SYM_BIND(x) ((x) >> 4)
// Symbol binding values from st_info
#define STB_LOCAL 0 /* Symbol not visible outside object */
#define STB_GLOBAL 1 /* Symbol visible to all object files */
#define STB_WEAK 2 /* Similar to STB_GLOBAL */
// Symbol type values from st_info
#define STT_NOTYPE 0 /* Not specified */
#define STT_OBJECT 1 /* Data object e.g. variable */
#define STT_FUNC 2 /* Function */
#define STT_SECTION 3 /* Section */
#define STT_FILE 4 /* Source file associated with object file */
// Special section header index values from st_shndex
#define SHN_UNDEF 0
#define SHN_LOPROC 0xFF00 /* Extended values */
#define SHN_ABS 0xFFF1 /* Absolute value: don't relocate */
#define SHN_COMMON 0xFFF2 /* Common block. Not allocated yet */
#define SHN_HIPROC 0xFF1F
#define SHN_HIRESERVE 0xFFFF
// Relocation entry with implicit addend (info about how to relocate)
typedef struct {
Elf32_Addr r_offset; /* Address */
Elf32_Word r_info; /* Relocation type and symbol index */
} Elf32_Rel;
// Relocation entry with explicit addend (info about how to relocate)
typedef struct {
Elf32_Addr r_offset; /* Address */
Elf32_Word r_info; /* Relocation type and symbol index */
Elf32_Sword r_addend; /* Addend */
} Elf32_Rela;
// Access macros for the relocation info
#define REL_TYPE(x) ((byte) (x)) /* Extract relocation type */
#define REL_INDEX(x) ((x)>>8) /* Extract relocation index into symbol table */
//MIPS relocation types
#define R_MIPS_NONE 0
#define R_MIPS_16 1
#define R_MIPS_32 2
#define R_MIPS_REL32 3
#define R_MIPS_26 4
#define R_MIPS_HI16 5
#define R_MIPS_LO16 6
#define R_MIPS_GPREL16 7
#define R_MIPS_LITERAL 8
#define R_MIPS_GOT16 9
#define R_MIPS_PC16 10
#define R_MIPS_CALL16 11
#define R_MIPS_GPREL32 12
#define R_MIPS_GOTHI16 13
#define R_MIPS_GOTLO16 14
#define R_MIPS_CALLHI16 15
#define R_MIPS_CALLLO16 16
// ARM relocation types
#define R_ARM_NONE 0
#define R_ARM_ABS32 2
#define R_ARM_THM_CALL 10
#define R_ARM_CALL 28
#define R_ARM_JUMP24 29
#define R_ARM_TARGET1 38
#define R_ARM_V4BX 40
// PPC relocation types
#define R_PPC_ADDR32 1
#define R_PPC_ADDR16_LO 4
#define R_PPC_ADDR16_HI 5
#define R_PPC_ADDR16_HA 6
#define R_PPC_REL24 10
#define R_PPC_REL32 26
#endif // defined(DYNAMIC_MODULES) && defined(USE_ELF_LOADER)
#endif /* BACKENDS_ELF_H */
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