Messages in this thread | | | Date | Tue, 14 Jan 2014 10:05:25 +0100 | Subject | Re: [PATCH V6 6/8] Add EFI stub for ARM | From | Ard Biesheuvel <> |
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On 10 January 2014 17:30, Roy Franz <roy.franz@linaro.org> wrote: > This patch adds EFI stub support for the ARM Linux kernel. The EFI stub > operates similarly to the x86 stub: it is a shim between the EFI firmware > and the normal zImage entry point, and sets up the environment that the > zImage is expecting. This includes loading the initrd (optionaly) and > device tree from the system partition based on the kernel command line. > The stub updates the device tree as necessary, adding entries for EFI > runtime services. The PE/COFF "MZ" header at offset 0 results in the > first instruction being an add that corrupts r5, which is not used by > the zImage interface. > > Signed-off-by: Roy Franz <roy.franz@linaro.org> > Acked-by: Grant Likely <grant.likely@linaro.org> > ---
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> diff --git a/arch/arm/boot/compressed/efi-header.S b/arch/arm/boot/compressed/efi-header.S > new file mode 100644 > index 0000000..dbb7101 > --- /dev/null > +++ b/arch/arm/boot/compressed/efi-header.S > @@ -0,0 +1,117 @@ > +@ Copyright (C) 2013 Linaro Ltd; <roy.franz@linaro.org> > +@ > +@ This file contains the PE/COFF header that is part of the > +@ EFI stub. > +@ > + > + .org 0x3c > + @ > + @ The PE header can be anywhere in the file, but for > + @ simplicity we keep it together with the MSDOS header > + @ The offset to the PE/COFF header needs to be at offset > + @ 0x3C in the MSDOS header. > + @ The only 2 fields of the MSDOS header that are used are this > + @ PE/COFF offset, and the "MZ" bytes at offset 0x0. > + @ > + .long pe_header @ Offset to the PE header. > + > + .align 3 > +pe_header: > + .ascii "PE" > + .short 0 > + > +coff_header: > + .short 0x01c2 @ ARM or Thumb
Could you explain why you are using 0x1c2 (Thumb) here and not 0x1c0 (ARM) ?
Cheers, Ard.
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