OSDev.org

Posted: **Sun Mar 09, 2008 10:36 pm**

Does anybody have a sample linker script that keeps rodata?
I need to link a simple C file against my library and have the out format be binary.

Thanks, JL

Posted: **Mon Mar 10, 2008 1:15 am**

Try linker.ld from the Bare Bones tutorial.

Posted: **Mon Mar 10, 2008 4:53 pm**

Well, my kernel simply loads the binary into memory and jumps to it.
With this code and the Bare Bones script:

Code: Select all

char b[16];
	b[0] = 'S';
	b[1] = 'y';
	b[2] = 'n';
	b[3] = 'c';
	b[4] = 'i';
	b[5] = 'n';
	b[6] = 'g';
	b[7] = '\n';
	b[8] = '\0';
	kputs(b);
	kputs("fine");

I get:

Code: Select all

Syncing

And thats it.
It should say 'fine'....Do you need any more info?

-JL

Posted: **Mon Mar 10, 2008 9:28 pm**

Objdump your executable and make sure the data is really in there. Dissassemble the relevant source and make sure it is pointing to your rodata section.

Posted: **Mon Mar 10, 2008 9:55 pm**

Objdump output (when I compile it to an elf):

Code: Select all

Disassembly of section .rodata:

00101000 <_ebss-0x18>:
  101000:       66 69 6e 65 00 2e       imul   $0x2e00,0x65(%esi),%bp
  101006:       2e 2e 00 77 6f          add    %dh,%cs:0x6f(%edi)
  10100b:       72 6b                   jb     101078 <_ebss+0x60>
  10100d:       3f                      aas
  10100e:       00 57 61                add    %dl,0x61(%edi)
  101011:       69                      .byte 0x69
  101012:       74 2e                   je     101042 <_ebss+0x2a>
  101014:       2e                      cs
  101015:       2e                      cs
        ...

So it looks like it's there...Edit: Is the actual data there?
Heres a newer one:

Code: Select all

	char b[16];
	b[0] = 'S';
	b[1] = 'y';
	b[2] = 'n';
	b[3] = 'c';
	b[4] = 'i';
	b[5] = 'n';
	b[6] = 'g';
	b[7] = '\n';
	b[8] = '\0';
	kputs(b);
	char c[16] = "Hello!\0";
	kputs(c);

Goes to

Code: Select all

Disassembly of section .rodata:

08048103 <.rodata>:
 8048103:       48                      dec    %eax
 8048104:       65                      gs
 8048105:       6c                      insb   (%dx),%es:(%edi)
 8048106:       6c                      insb   (%dx),%es:(%edi)
 8048107:       6f                      outsl  %ds:(%esi),(%dx)
 8048108:       21 00                   and    %eax,(%eax)

-JL

OSDev.org

Linker script rodata

Linker script rodata