[PATCH 1/5] arm64: PIE: Skip fixups if distance is zero

[Stephen Warren]

On 9/24/20 8:45 AM, André Przywara wrote:
> On 24/09/2020 01:17, Andre Przywara wrote:
>> When the actual offset between link and runtime address is zero, there
>> is no need for patching up U-Boot early when running with
>> CONFIG_POSITION_INDEPENDENT.
> 
> That turns out to be not fully true.
> Some toolchains (all Linaro cross compilers?) don't handle this well,
> they keep the original locations in the binary uninitialised, and rely
> on the reldyn fixup table to patch in the actual values.
> Other compilers (GCC 9.2 vanilla, Ubuntu GCC 7.5.0, Arm website 9.2)
> fill in the addresses both into the binary and the fixup, so this patch
> works.
> 
> It seems to be fixed by enabling CONFIG_STATIC_RELA?
> I see it's disabled for CONFIG_POSITION_INDEPENDENT, what was the reason
> behind that?

I can't remember for sure. I tried re-enabling STATIC_RELA at both the
upstream commit where POSITION_INDEPENDENT was first implemented and at
top-of-tree, and ran test/py on Tegra, and it works fine. Perhaps I just
figured there was no need to perform the static relocations since the
code would always do it? I figure it's safe to re-enable it, i.e.
decouple the two config options completely.