tree b7925508dce7ab7be718a41e329d5a53f7bd1706
parent 56fb1494500b1ef61ed097acfd4e204b9d4857b7
author Nicholas Piggin <npiggin@gmail.com> 1702734163 +1000
committer Thomas Huth <thuth@redhat.com> 1702992474 +0100

powerpc: Set .got section alignment to 256 bytes

Modern powerpc64 toolchains require the .got section have alignment of
256 bytes. Incorrect alignment ends up causing the .data section ELF
load address to move by 8 bytes from its file offset, relative to
previous sections. This is not a problem for the QEMU bios loader used
by the pseries machine, but it is a problem for the powernv machine
using skiboot as the bios and the test programs as a kernel, because the
skiboot ELF loader is crippled:

  * Note that we execute the kernel in-place, we don't actually
  * obey the load informations in the headers. This is expected
  * to work for the Linux Kernel because it's a fairly dumb ELF
  * but it will not work for any ELF binary.

This causes all references to data to be incorrect. Aligning the .got
to 256 bytes prevents this offset skew and allows the skiboot "flat"
loader to work. [I don't know why the .got alignment can cause this
difference in linking.]

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Message-ID: <20231216134257.1743345-17-npiggin@gmail.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>