Re: Relocation fixup during AARCH64 SEC PE-COFF generation?

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On 13 September 2016 at 15:03, Achin Gupta <achin.gupta@arm.com> wrote:
> Hi All,
>
> Upon entry into UEFI, the ArmPlatformPkg/PrePi/PeiUniCore.inf SEC module
> executes directly from within the firmware volume. The FV would typically be
> loaded in DRAM by ARM Trusted Firmware. The rule in ArmJuno.fdf for SEC file
> types converts a PE-COFF module into a stripped Terse executable as follows:
>
> [Rule.AARCH64.SEC]
>   FILE SEC = $(NAMED_GUID) RELOCS_STRIPPED FIXED {
>     TE  TE    Align = Auto              $(INF_OUTPUT)/$(MODULE_NAME).efi
>   }
>
> The GCC_ARM_AARCH64_DLINK_COMMON variable includes the "--emit-relocs" option
> when the ELF image is generated. Since the SEC module is able to "XIP" from the
> within FV, this means that the relocations have to be fixed up at link time
> before the TE image is created.
>

Correct. GenFv relocates the image based on the runtime address of the
firmware volume.

> It seems to me that in GenFw.c, at least the static relocations are fixed up
> when an ELF image is converted to PE-COFF. Can someone confirm if I am correct
> in understanding that dynamic relocations will be left as is in the PE-COFF
> image while static relocations will be fixed up?
>

We usually don't emit dynamic relocations, since we are not linking
shared objects.