arm64: VHE: Enable EL2 MMU from the idmap

Browse source

Enabling the MMU requires the write to SCTLR_ELx (and the ISB
that follows) to live in some identity-mapped memory. Otherwise,
the translation will result in something totally unexpected
(either fetching the wrong instruction stream, or taking a
fault of some sort).

This is exactly what happens in mutate_to_vhe(), as this code
lives in the .hyp.text section, which isn't identity-mapped.
With the right configuration, this explodes badly.

Extract the MMU-enabling part of mutate_to_vhe(), and move
it to its own function that lives in the idmap. This ensures
nothing bad happens.

Fixes: f359182291 ("arm64: Provide an 'upgrade to VHE' stub hypercall")
Reported-by: "kernelci.org bot" <bot@kernelci.org>
Tested-by: Guillaume Tucker <guillaume.tucker@collabora.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210224093738.3629662-2-maz@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

...

This commit is contained in:

Marc Zyngier 2021-02-24 09:37:36 +00:00 • committed by Will Deacon

parent 610e4dc8ac

commit f1b6cff7c9

1 changed files with 26 additions and 13 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

39

arch/arm64/kernel/hyp-stub.S

View file