Re: Problem loading a multiboot kernel

[Vincent Girard-Reydet]

Le Mercredi 30 Juillet 2003 02:47, Jeff Sheinberg a écrit :
> Vincent Girard-Reydet writes:
>  > Hope this is the rightplace to post my question. I'm currently
>  > working on a kernel that I made multiboot compliant.
>  >
>  > This kernel is linked as an ELF program, section .text starting
>  > at 0xc0000000.  As I need to configure the paged memory before
>  > switching to high addresses, I must load my kernel at a much
>  > lower address. So I ask in my Multiboot header to be loaded at
>  > 0x100000, and I use translation tricks (leal and co) to get my
>  > code working untill the pagination is activated.
>  >
>  > But Grub won't load my kernel. I checked the addresses in the
>  > Multiboot header with objdump, they are correct. I put an
>  > instruction that prints a character on the screen and loops at
>  > the cery end of my kernel, to only check if I'm booted. But the
>  > machine reboots when Grub loads the kernel.
>
> Have you tried "mbchk YOUR_KERNEL", try "info mbchk" for details.

Here is the output of mbchk :

The Multiboot header is found at the offset 4100.
/mnt/tmp/kernel.bin: Page alignment is turned off.
/mnt/tmp/kernel.bin: Memory information is turned on.
/mnt/tmp/kernel.bin: Address fields is turned on.
/mnt/tmp/kernel.bin: All checks passed.

For info, here are the ELF headers of my file :

bash-2.05b$ objdump -ph /mnt/tmp/kernel.bin

/mnt/tmp/kernel.bin:     file format elf32-i386

Program Header:
    LOAD off    0x00001000 vaddr 0xc0000000 paddr 0xc0000000 align 2**12
         filesz 0x00008c68 memsz 0x0001bed4 flags rwx

Sections:
Idx Name          Size      VMA       LMA       File off  Algn
  0 .text         000050f7  c0000000  c0000000  00001000  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, CODE
  1 .data         00003b68  c0005100  c0005100  00006100  2**5
                  CONTENTS, ALLOC, LOAD, DATA
  2 .bss          00012ed4  c0009000  c0009000  0000a000  2**12
                  ALLOC
  3 .debug_line   00003a3a  00000000  00000000  0000a000  2**0
                  CONTENTS, READONLY, DEBUGGING
  4 .debug_info   00009b3d  00000000  00000000  0000da3a  2**0
                  CONTENTS, READONLY, DEBUGGING
  5 .debug_abbrev 000020b7  00000000  00000000  00017577  2**0
                  CONTENTS, READONLY, DEBUGGING
  6 .debug_aranges 00000470  00000000  00000000  00019630  2**3
                  CONTENTS, READONLY, DEBUGGING
  7 .debug_frame  0000124c  00000000  00000000  00019aa0  2**2
                  CONTENTS, READONLY, DEBUGGING
  8 .debug_pubnames 0000060c  00000000  00000000  0001acec  2**0
                  CONTENTS, READONLY, DEBUGGING
  9 .debug_str    0000168c  00000000  00000000  0001b2f8  2**0
                  CONTENTS, READONLY, DEBUGGING
 10 .comment      00000640  00000000  00000000  0001c984  2**0
                  CONTENTS, READONLY