How to install a function in section and to call the function

1) __attribute__((section("section_name")))
 fuctions: put the functions and datas into in the section pointed by "section_name"
 
 #define STR(x) (#x)
 #define ERIC_ATTRIB_SECTION(setction) __attribute__((section(setction)))
 
 #define ERIC_TAB_ENTRY( _name ) \
        ERIC_ATTRIB_SECTION(".eric.table." STR(_name) ".data")
 
2)"#" and "##"

  (1)"#" symbol convert a symbol to string.
 #define STR(x) (#x)
 
  (2)"##" symbol is used to connect the two symbols
 #define STR_LINK(x, y) (x##y)

3) how to use __asm__

    __asm__ __volatile__(
      assembly language part:
      output    part:
      input    part:
      broken    part:
 )
   (1) we use ";" "\n" or "\n\t" to distinguish expression of the assembly language part
  we could use the following example to use __asm__

  #define str(x) #x
  #define LAB(x) x

  #define ERIC_TAB_BEGIN(label, name)                                 \
  __asm__(".section \".eric.table." str(name) ".begin\",\"aw\"\n"     \
    ".globl " str(LAB(label)) "\n"                         \
    ".type    " str(LAB(label)) ",object\n"                \
    ".p2align " str(LAB) "\n"                           \
    str(LAB(_label)) ":\n"                               \
    ".previous\n"                                         \
  )
 
4) how to use above data struct
 (1)we use the ERIC_TAB_BEGIN to start a new read_write section
    and also we can use ERIC_TAB_END(.begin->.finish) to end a section
 
 (2)how to use the ERIC_TAB_ENTRY to install test
    a) we can define the following data struct
 struct lib_init_sturct{
  unsigned int id;
  unsigned int p_id;
  int (*call_func)(void*);
 };
 typedef struct lib_init_sturct lib_init_s;
 
 b) we can install the following func to install the function to the section
 #define LIB_INIT_ENTRY(__name, _id, _p_id, _call_func) \
  static int _call_func(void* ptr); \
  lib_init_s __name \ ERIC_TAB_ENTRY(eric_lib_init_table) = \
  {
       .id   = _id, \
       .p_id   = _p_id, \
       .call_func  = _call_func
  }
 such as: LIB_INIT_ENTRY(eric_table, 0x600, 0x20, eric_initiate_hw)
 
 (3) how to use the call the function in the section
 1)we can define the following datastruct to define the section.
 ERIC_TABLE_BEGIN(_lib_init_table, eric_lib_init_table);
 ERIC_TABLE_END(_lib_init_table_end, eric_lib_init_table);
 extern lib_init_s _lib_init_table[];
 extern lib_init_s _lib_init_table_end[];
 
 2)we can use the following codes to call the entry that installed in the section
 int init_eric_lib(unsigned int lib_id,  unsigned int product_id, void* ptr)
 {
      lib_init_s* init = NULL;
      int result = -1;
      for (init = &_lib_init_table[0]; init != (lib_init_s*)&_lib_init_table_end; init++)
      {
           if (product_id == init->prod_id && lib_id == init->lib_id)
          {
                result = init->call_func(ptr);
                break;
          }
      }
      return result;
 }