GAS（GCC/AS）自动生成.TEXT，.DATA和.BSS部分，即使这些部分不在文件中

Question

我正在尝试将OS开发教程从NASM Intel语法移植到GAS（GCC/AS）。

有一个文件只有一个部分（.multiboot_header），该文件仅包含引导加载程序的数据。我在Intel和AT＆amp; t语法上都有该文件，但是当我编译它们时，用燃气编译的一个部分会产生源文件中要求的部分：

NASM：

~$ objdump -h multiboot_header.asm.o 

multiboot_header.asm.o:     file format elf64-x86-64

Sections:
Idx Name          Size      VMA               LMA               File off  Algn
  0 .multiboot_header 0000000c  0000000000000000  0000000000000000  00000180  2**0
                  CONTENTS, ALLOC, LOAD, READONLY, DATA

GCC： GCC：

$ objdump -h multiboot_header.S.o

multiboot_header.S.o:     file format elf64-x86-64

Sections:
Idx Name          Size      VMA               LMA               File off  Algn
  0 .text         00000000  0000000000000000  0000000000000000  00000040  2**0
                  CONTENTS, ALLOC, LOAD, READONLY, CODE
  1 .data         00000000  0000000000000000  0000000000000000  00000040  2**0
                  CONTENTS, ALLOC, LOAD, DATA
  2 .bss          00000000  0000000000000000  0000000000000000  00000040  2**0
                  ALLOC
  3 .multiboot_header 0000000c  0000000000000000  0000000000000000  00000040  2**0
                  CONTENTS, READONLY

正如您可以看到GCC生成了额外的部分，并且文件偏移也不完全相同。为什么会发生这种情况，我该如何解决？

编辑：

教程我关注： https://os.phil-opp.com/multiboot--multiboot--内核/

这是链接器脚本IM使用：

ENTRY(start)

SECTIONS {
    . = 1M;
    
    .boot :
    {
        /* ensure that the multiboot header is at the beginning */
        *(.multiboot_header)
    }
    
    .text :
    {
        *(.text)
    }
}

另外，这是Multiboot_header.s文件：

.section .multiboot_header
header_start:
    .long 0xe85250d6        # magic number (multiboot 2)
    .long 0             # architecture 0 (protected mode x86)
    .long header_end - header_start # header lenght
    # checksum
    .long 0x100000000 - (0xe85250d6 + 0 + (header_end - header_start))
    
    # insert optional multiboot tags here
    
    # required end tag
    .word 0 # type
        .word 0 # flags
        .long 8 # size
header_end:

readelf -s的输出-S构建/kernel-x86_64.bin with Gas：

There are 6 section headers, starting at offset 0x1d8:

Section Headers:
  [Nr] Name              Type             Address           Offset         Size              EntSize          Flags  Link  Info  Align
  [ 0]                   NULL             0000000000000000  00000000       0000000000000000  0000000000000000           0     0     0
  [ 1] .boot             PROGBITS         0000000000100000  000000ee       0000000000000018  0000000000000000           0     0     1
  [ 2] .text             PROGBITS         0000000000100000  00000078       0000000000000076  0000000000000000  AX       0     0     1
  [ 3] .symtab           SYMTAB           0000000000000000  00000108       0000000000000078  0000000000000018           4     4     8
  [ 4] .strtab           STRTAB           0000000000000000  00000180       000000000000002c  0000000000000000           0     0     1
  [ 5] .shstrtab         STRTAB           0000000000000000  000001ac       0000000000000027  0000000000000000           0     0     1
Key to Flags:
  W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
  L (link order), O (extra OS processing required), G (group), T (TLS),
  C (compressed), x (unknown), o (OS specific), E (exclude),
  D (mbind), l (large), p (processor specific)

with Nasm：

There are 6 section headers, starting at offset 0x228:

Section Headers:
  [Nr] Name              Type             Address           Offset         Size              EntSize          Flags  Link  Info  Align
  [ 0]                   NULL             0000000000000000  00000000       0000000000000000  0000000000000000           0     0     0
  [ 1] .boot             PROGBITS         0000000000100000  00000080       0000000000000018  0000000000000000   A       0     0     1
  [ 2] .text             PROGBITS         0000000000100020  000000a0       0000000000000076  0000000000000000  AX       0     0     16
  [ 3] .symtab           SYMTAB           0000000000000000  00000118       0000000000000090  0000000000000018           4     5     8
  [ 4] .strtab           STRTAB           0000000000000000  000001a8       0000000000000059  0000000000000000           0     0     1
  [ 5] .shstrtab         STRTAB           0000000000000000  00000201       0000000000000027  0000000000000000           0     0     1
Key to Flags:
  W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
  L (link order), O (extra OS processing required), G (group), T (TLS),
  C (compressed), x (unknown), o (OS specific), E (exclude),
  D (mbind), l (large), p (processor specific)