Hi,
Apple's A10(X), T2 SoCs consists of pairs of performance and efficiency
cores. However, only one of the core types may be active at a given time,
and to software, it appears as logical cores that could switch between
P-mode and E-mode, depending on the p-state.
Unforunately, only the performance cores can execute 32-bit EL0. To
software, this results in logical cores that lose ability to execute
32-bit EL0 when the p-state is below a certain value.
Since these CPU cores only supported 16K pages, many AArch32
executables will not run anyways. This series disables 32-bit EL0 for
these SoCs.
Nick Chan
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Nick Chan (2):
arm64: cputype: Add CPU types for A7-A11, T2 SoCs
arm64: cpufeature: Pretend that Apple A10(X), T2 does not support
32-bit EL0
arch/arm64/include/asm/cputype.h | 42 +++++++++++++++++++++++---------
arch/arm64/kernel/cpufeature.c | 25 +++++++++++++++++++
2 files changed, 55 insertions(+), 12 deletions(-)
base-commit: 9aaeb87ce1e966169a57f53a02ba05b30880ffb8
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2.46.0