module.h

/*
 * File      : module.c
 * This file is part of RT-Thread RTOS
 * COPYRIGHT (C) 2006 - 2012, RT-Thread Development Team
 *
 * The license and distribution terms for this file may be
 * found in the file LICENSE in this distribution or at
 * http://www.rt-thread.org/license/LICENSE
 *
 * Change Logs:
 * Date           Author       Notes
 * 2010-01-09     Bernard      first version
 * 2010-04-09     yi.qiu       implement based on first version
 */
 
#ifndef __MODULE_H__
#define __MODULE_H__

#include <rtdef.h>

typedef rt_uint8_t  Elf_Byte;

typedef rt_uint32_t Elf32_Addr;     /* Unsigned program address */
typedef rt_uint32_t Elf32_Off;      /* Unsigned file offset */
typedef rt_int32_t  Elf32_Sword;    /* Signed large integer */
typedef rt_uint32_t Elf32_Word;     /* Unsigned large integer */
typedef rt_uint16_t Elf32_Half;     /* Unsigned medium integer */

/* e_ident[] magic number */
#define    ELFMAG0     0x7f        /* e_ident[EI_MAG0] */
#define    ELFMAG1     'E'         /* e_ident[EI_MAG1] */
#define    ELFMAG2     'L'         /* e_ident[EI_MAG2] */
#define    ELFMAG3     'F'         /* e_ident[EI_MAG3] */
#define    RTMMAG      "\177RTM"   /* magic */
#define    ELFMAG      "\177ELF"   /* magic */
#define    SELFMAG     4           /* size of magic */

#define EI_CLASS    4           /* file class */
#define EI_NIDENT   16          /* Size of e_ident[] */

/* e_ident[] file class */
#define    ELFCLASSNONE    0       /* invalid */
#define    ELFCLASS32      1       /* 32-bit objs */
#define    ELFCLASS64      2       /* 64-bit objs */
#define    ELFCLASSNUM     3       /* number of classes */

/* e_ident[] data encoding */
#define ELFDATANONE     0       /* invalid */
#define ELFDATA2LSB     1       /* Little-Endian */
#define ELFDATA2MSB     2       /* Big-Endian */
#define ELFDATANUM      3       /* number of data encode defines */

/* e_ident */
#define IS_ELF(ehdr) ((ehdr).e_ident[EI_MAG0] == ELFMAG0 && \
                      (ehdr).e_ident[EI_MAG1] == ELFMAG1 && \
                      (ehdr).e_ident[EI_MAG2] == ELFMAG2 && \
                      (ehdr).e_ident[EI_MAG3] == ELFMAG3)

#define ET_NONE         0               /* No file type */
#define ET_REL          1               /* Relocatable file */
#define ET_EXEC         2               /* Executable file */
#define ET_DYN          3               /* Shared object file */
#define ET_CORE         4               /* Core file */

/* ELF Header */
typedef struct elfhdr
{
    unsigned char e_ident[EI_NIDENT]; /* ELF Identification */
    Elf32_Half    e_type;             /* object file type */
    Elf32_Half    e_machine;          /* machine */
    Elf32_Word    e_version;          /* object file version */
    Elf32_Addr    e_entry;            /* virtual entry point */
    Elf32_Off     e_phoff;            /* program header table offset */
    Elf32_Off     e_shoff;            /* section header table offset */
    Elf32_Word    e_flags;            /* processor-specific flags */
    Elf32_Half    e_ehsize;           /* ELF header size */
    Elf32_Half    e_phentsize;        /* program header entry size */
    Elf32_Half    e_phnum;            /* number of program header entries */
    Elf32_Half    e_shentsize;        /* section header entry size */
    Elf32_Half    e_shnum;            /* number of section header entries */
    Elf32_Half    e_shstrndx;         /* section header table's "section
                                         header string table" entry offset */
} Elf32_Ehdr;

/* Section Header */
typedef struct
{
    Elf32_Word sh_name;      /* name - index into section header
                                string table section */
    Elf32_Word sh_type;      /* type */
    Elf32_Word sh_flags;     /* flags */
    Elf32_Addr sh_addr;      /* address */
    Elf32_Off  sh_offset;    /* file offset */
    Elf32_Word sh_size;      /* section size */
    Elf32_Word sh_link;      /* section header table index link */
    Elf32_Word sh_info;      /* extra information */
    Elf32_Word sh_addralign; /* address alignment */
    Elf32_Word sh_entsize;   /* section entry size */
} Elf32_Shdr;

/* Section names */
#define ELF_BSS         ".bss"         /* uninitialized data */
#define ELF_DATA        ".data"        /* initialized data */
#define ELF_DEBUG       ".debug"       /* debug */
#define ELF_DYNAMIC     ".dynamic"     /* dynamic linking information */
#define ELF_DYNSTR      ".dynstr"      /* dynamic string table */
#define ELF_DYNSYM      ".dynsym"      /* dynamic symbol table */
#define ELF_FINI        ".fini"        /* termination code */
#define ELF_GOT         ".got"         /* global offset table */
#define ELF_HASH        ".hash"        /* symbol hash table */
#define ELF_INIT        ".init"        /* initialization code */
#define ELF_REL_DATA    ".rel.data"    /* relocation data */
#define ELF_REL_FINI    ".rel.fini"    /* relocation termination code */
#define ELF_REL_INIT    ".rel.init"    /* relocation initialization code */
#define ELF_REL_DYN     ".rel.dyn"     /* relocaltion dynamic link info */
#define ELF_REL_RODATA  ".rel.rodata"  /* relocation read-only data */
#define ELF_REL_TEXT    ".rel.text"    /* relocation code */
#define ELF_RODATA      ".rodata"      /* read-only data */
#define ELF_SHSTRTAB    ".shstrtab"    /* section header string table */
#define ELF_STRTAB      ".strtab"      /* string table */
#define ELF_SYMTAB      ".symtab"      /* symbol table */
#define ELF_TEXT        ".text"        /* code */
#define ELF_RTMSYMTAB   "RTMSymTab"

/* Symbol Table Entry */
typedef struct elf32_sym
{
    Elf32_Word    st_name;  /* name - index into string table */
    Elf32_Addr    st_value; /* symbol value */
    Elf32_Word    st_size;  /* symbol size */
    unsigned char st_info;  /* type and binding */
    unsigned char st_other; /* 0 - no defined meaning */
    Elf32_Half    st_shndx; /* section header index */
} Elf32_Sym;

#define    STB_LOCAL   0       /* BIND */
#define    STB_GLOBAL  1
#define    STB_WEAK    2
#define    STB_NUM     3
 
#define    STB_LOPROC  13      /* processor specific range */
#define    STB_HIPROC  15

#define    STT_NOTYPE  0       /* symbol type is unspecified */
#define    STT_OBJECT  1       /* data object */
#define    STT_FUNC    2       /* code object */
#define    STT_SECTION 3       /* symbol identifies an ELF section */
#define    STT_FILE    4       /* symbol's name is file name */
#define    STT_COMMON  5       /* common data object */
#define    STT_TLS     6       /* thread-local data object */
#define    STT_NUM     7       /* # defined types in generic range */
#define    STT_LOOS    10      /* OS specific range */
#define    STT_HIOS    12
#define    STT_LOPROC  13      /* processor specific range */
#define    STT_HIPROC  15
    
#define STN_UNDEF       0               /* undefined */

#define    ELF_ST_BIND(info)           ((info) >> 4)
#define    ELF_ST_TYPE(info)           ((info) & 0xf)
#define    ELF_ST_INFO(bind, type)     (((bind)<<4)+((type)&0xf))    

/* Relocation entry with implicit addend */
typedef struct
{
    Elf32_Addr r_offset;   /* offset of relocation */
    Elf32_Word r_info;     /* symbol table index and type */
} Elf32_Rel;

/* Relocation entry with explicit addend */
typedef struct
{
    Elf32_Addr  r_offset;   /* offset of relocation */
    Elf32_Word  r_info;     /* symbol table index and type */
    Elf32_Sword r_addend;
} Elf32_Rela;

/* Extract relocation info - r_info */
#define ELF32_R_SYM(i)      ((i) >> 8)
#define ELF32_R_TYPE(i)     ((unsigned char) (i))
#define ELF32_R_INFO(s,t)   (((s) << 8) + (unsigned char)(t))

/*
 * Relocation type for arm
 */
#define    R_ARM_NONE            0
#define    R_ARM_PC24            1
#define    R_ARM_ABS32            2
#define    R_ARM_REL32            3
#define R_ARM_THM_CALL        10
#define    R_ARM_GLOB_DAT        21
#define    R_ARM_JUMP_SLOT        22
#define    R_ARM_RELATIVE        23
#define    R_ARM_GOT_BREL        26
#define    R_ARM_PLT32            27
#define    R_ARM_CALL            28
#define    R_ARM_JUMP24        29
#define R_ARM_THM_JUMP24    30
#define    R_ARM_V4BX            40

/* Program Header */
typedef struct
{
    Elf32_Word p_type;      /* segment type */
    Elf32_Off  p_offset;    /* segment offset */
    Elf32_Addr p_vaddr;     /* virtual address of segment */
    Elf32_Addr p_paddr;     /* physical address - ignored? */
    Elf32_Word p_filesz;    /* number of bytes in file for seg. */
    Elf32_Word p_memsz;     /* number of bytes in mem. for seg. */
    Elf32_Word p_flags;     /* flags */
    Elf32_Word p_align;     /* memory alignment */
} Elf32_Phdr;

/* p_type */
#define PT_LOAD      1

/* p_flags */
#define PF_X         1
#define PF_W         2
#define PF_R         4

/* sh_type */
#define SHT_NULL     0      /* inactive */
#define SHT_PROGBITS 1      /* program defined information */
#define SHT_SYMTAB   2      /* symbol table section */
#define SHT_STRTAB   3      /* string table section */
#define SHT_RELA     4      /* relocation section with addends*/
#define SHT_HASH     5      /* symbol hash table section */
#define SHT_DYNAMIC  6      /* dynamic section */
#define SHT_NOTE     7      /* note section */
#define SHT_NOBITS   8      /* no space section */
#define SHT_REL      9      /* relation section without addends */
#define SHT_SHLIB    10     /* reserved - purpose unknown */
#define SHT_DYNSYM   11     /* dynamic symbol table section */
#define SHT_NUM      12     /* number of section types */
#define SHT_LOPROC   0x70000000 /* reserved range for processor */
#define SHT_HIPROC   0x7fffffff /* specific section header types */
#define SHT_LOUSER   0x80000000 /* reserved range for application */
#define SHT_HIUSER   0xffffffff /* specific indexes */

/* Section Attribute Flags - sh_flags */
#define SHF_WRITE    0x1        /* Writable */
#define SHF_ALLOC    0x2        /* occupies memory */
#define SHF_EXECINSTR   0x4     /* executable */
#define SHF_MASKPROC    0xf0000000  /* reserved bits for processor */
/* specific section attributes */

#endif