Re: [Qemu-devel] [PATCH][RFC] elf loader: use the virtual address

["Laurent Desnogues" <laurent.desnogues@gmail.com>]

On Fri, Jan 9, 2009 at 4:47 PM, Aurelien Jarno <aurelien@aurel32.net> wrote:
> Most Linux kernels have their physical address corresponding to they
> virtual address in the ELF header. This is however not true anymore for
> the PowerPC kernels (>= 2.6.25).
>
> For PowerPC, the kernel needs to be started with address translation
> enabled (that's even true for the firmware), and thus the kernel loaded
> at the virtual address.
>
> As all the other kernels/bios I have looked have the same virtual and
> physical address, I don't think it will break other targets. This is
> what is done in the patch below. Alternatively, we can add a new
> argument to the load_elf functions, to select between virtual and
> physical load address.
>
> Any opinon?

I wonder if some platforms don't use the address_offset parameter
to simulate that behaviour.

Anyway wouldn't a parameter be cleaner and allow more flexibility?


Laurent

> diff --git a/elf_ops.h b/elf_ops.h
> index feea12f..19d1a5e 100644
> --- a/elf_ops.h
> +++ b/elf_ops.h
> @@ -231,7 +231,7 @@ static int glue(load_elf, SZ)(int fd, int64_t address_offset,
>             }
>             /* address_offset is hack for kernel images that are
>                linked at the wrong physical address.  */
> -            addr = ph->p_paddr + address_offset;
> +            addr = ph->p_vaddr + address_offset;
>
>             cpu_physical_memory_write_rom(addr, data, mem_size);
>
> --
>  .''`.  Aurelien Jarno             | GPG: 1024D/F1BCDB73
>  : :' :  Debian developer           | Electrical Engineer
>  `. `'   aurel32@debian.org         | aurelien@aurel32.net
>   `-    people.debian.org/~aurel32 | www.aurel32.net
>
>
>