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H A D | proton-pack.c | ea8f8c99 Tue Oct 20 10:01:57 CDT 2020 Will Deacon <will@kernel.org> arm64: spectre-v2: Favour CPU-specific mitigation at EL2
Spectre-v2 can be mitigated on Falkor CPUs either by calling into firmware or by issuing a magic, CPU-specific sequence of branches. Although the latter is faster, the size of the code sequence means that it cannot be used in the EL2 vectors, and so there is a need for both mitigations to co-exist in order to achieve optimal performance.
Change the mitigation selection logic for Spectre-v2 so that the CPU-specific mitigation is used only when the firmware mitigation is also available, rather than when a firmware mitigation is unavailable.
Cc: Marc Zyngier <maz@kernel.org> Signed-off-by: Will Deacon <will@kernel.org> ea8f8c99 Tue Oct 20 10:01:57 CDT 2020 Will Deacon <will@kernel.org> arm64: spectre-v2: Favour CPU-specific mitigation at EL2 Spectre-v2 can be mitigated on Falkor CPUs either by calling into firmware or by issuing a magic, CPU-specific sequence of branches. Although the latter is faster, the size of the code sequence means that it cannot be used in the EL2 vectors, and so there is a need for both mitigations to co-exist in order to achieve optimal performance. Change the mitigation selection logic for Spectre-v2 so that the CPU-specific mitigation is used only when the firmware mitigation is also available, rather than when a firmware mitigation is unavailable. Cc: Marc Zyngier <maz@kernel.org> Signed-off-by: Will Deacon <will@kernel.org>
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