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author | dann frazier <dann.frazier@canonical.com> | 2021-09-23 16:50:02 +0200 |
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committer | Catalin Marinas <catalin.marinas@arm.com> | 2021-09-23 16:59:15 +0200 |
commit | 22b70e6f2da0a4c8b1421b00cfc3016bc9d4d9d4 (patch) | |
tree | bbd4e04dcf32a7db7296e56a6d1905389d2c9288 /arch/arm64/mm/hugetlbpage.c | |
parent | kselftest/arm64: signal: Skip tests if required features are missing (diff) | |
download | linux-22b70e6f2da0a4c8b1421b00cfc3016bc9d4d9d4.tar.xz linux-22b70e6f2da0a4c8b1421b00cfc3016bc9d4d9d4.zip |
arm64: Restore forced disabling of KPTI on ThunderX
A noted side-effect of commit 0c6c2d3615ef ("arm64: Generate cpucaps.h")
is that cpucaps are now sorted, changing the enumeration order. This
assumed no dependencies between cpucaps, which turned out not to be true
in one case. UNMAP_KERNEL_AT_EL0 currently needs to be processed after
WORKAROUND_CAVIUM_27456. ThunderX systems are incompatible with KPTI, so
unmap_kernel_at_el0() bails if WORKAROUND_CAVIUM_27456 is set. But because
of the sorting, WORKAROUND_CAVIUM_27456 will not yet have been considered
when unmap_kernel_at_el0() checks for it, so the kernel tries to
run w/ KPTI - and quickly falls over.
Because all ThunderX implementations have homogeneous CPUs, we can remove
this dependency by just checking the current CPU for the erratum.
Fixes: 0c6c2d3615ef ("arm64: Generate cpucaps.h")
Cc: <stable@vger.kernel.org> # 5.13.x
Signed-off-by: dann frazier <dann.frazier@canonical.com>
Suggested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210923145002.3394558-1-dann.frazier@canonical.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/mm/hugetlbpage.c')
0 files changed, 0 insertions, 0 deletions