Re: [PATCH] mbi: use per segment a separate relocator chunk

[Alexander Boettcher]

On 15.05.2018 21:10, Alexander Boettcher wrote:
> > I assume that a given ELF PHDR address/size does not cover VGA memory or
> > anything like that, 
>
> No.
>
> > so, I am not sure what exactly overwrites this region.
> > grub_memset() in current line 161 at some point?
>
> No. During grub_relocator_prepare_reloc the overwrite happens, if i'm 
> not wrong.
>
> An (artificial) example, imagine two ELF PHDRs, e.g.
>
>   [0x8000-0x9000) and
>   [0x2000000-0x2100000).
>
> Without this patch grub calculates one relocator chunk of size 0x20f8000 
> (0x2100000 - 0x8000) and places it at some higher memory, e.g. 
> [0x3000000 - 0x30f8000). During the invocation of 

Must be [0x3000000-0x50f8000)

> grub_relocator_prepare_reloc the memory gets copied from
>
> [0x3000000-0x30f8000) to [0x8000-0x2100000)

Must be [0x3000000-0x50f8000) to [0x8000-0x2100000)


Sorry.

--
Alexander Boettcher
Genode Labs

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