[PATCH v2] arm64/efi: efistub: jump to 'stext' directly, not through the header

Mark Salter msalter at redhat.com
Wed Jul 16 07:51:37 PDT 2014


On Tue, 2014-07-15 at 12:58 +0200, Ard Biesheuvel wrote:
> After the EFI stub has done its business, it jumps into the kernel by branching
> to offset #0 of the loaded Image, which is where it expects to find the header
> containing a 'branch to stext' instruction.
> 
> However, the header is not covered by any PE/COFF section, so the header may
> not actually be loaded at the expected offset. So instead, jump to 'stext'
> directly, which is at the base of the PE/COFF .text section, by supplying a
> symbol 'stext_offset' to efi-entry.o which contains the relative offset of
> stext into the Image. Also replace other open coded calculations of the same
> value with a reference to 'stext_offset'

Have you actually seen a situation where the header isn't there?
Isn't the kernel header actually part of the pe/coff file and
firmware loads the whole file into RAM?





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