[RFT PATCH 0/2] ARM/arm64: module-plt: split core and init PLT sections

[ard.biesheuvel@linaro.org (Ard Biesheuvel)]

This fixes a thinko on my part in both the ARM and the arm64 implementations
of module PLTs. What I failed to realise is that the core module sections and
the init sections are allocated independently, which means they could end up
further away from each other than the range of a branch instruction. This
implies that they cannot share a single array of PLT entries, and so this
series splits them into core and init PLT sections.

For ARM, this is actually a revert of commit 35fa91eed817 ("ARM: kernel:
merge core and init PLTs") [although the patch in this series is not a
straight revert.] This means that the issue is a regression, and the patch
should probably go to -stable.

For arm64, the likelihood of this issue ever occurring is very small, due
to the 128 MB range of its branch instructions. Also, the arm64 version of
the code was never correct, so it is not a regression. But for correctness,
it is fixed in the same way as for ARM.

For now, these are build tested only. I was hoping Angus could check whether
1/2 makes his problems go away.

Ard Biesheuvel (2):
  ARM: module: split core and init PLT sections
  arm64: module: split core and init PLT sections

 arch/arm/include/asm/module.h   |  9 ++-
 arch/arm/kernel/module-plts.c   | 62 ++++++++++++++------
 arch/arm/kernel/module.lds      |  1 +
 arch/arm64/include/asm/module.h |  9 ++-
 arch/arm64/kernel/module-plts.c | 56 ++++++++++++------
 arch/arm64/kernel/module.c      |  2 +-
 arch/arm64/kernel/module.lds    |  1 +
 7 files changed, 99 insertions(+), 41 deletions(-)

-- 
2.7.4