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2019-10-29arm64: ssbd: Add support for PSTATE.SSBS rather than trapping to EL3Will Deacon
[ Upstream commit 8f04e8e6e29c93421a95b61cad62e3918425eac7 ] On CPUs with support for PSTATE.SSBS, the kernel can toggle the SSBD state without needing to call into firmware. This patch hooks into the existing SSBD infrastructure so that SSBS is used on CPUs that support it, but it's all made horribly complicated by the very real possibility of big/little systems that don't uniformly provide the new capability. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> [ardb: add #include of asm/compat.h] Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-22arm64: ssbd: Add prctl interface for per-thread mitigationMarc Zyngier
commit 9cdc0108baa8ef87c76ed834619886a46bd70cbe upstream. If running on a system that performs dynamic SSBD mitigation, allow userspace to request the mitigation for itself. This is implemented as a prctl call, allowing the mitigation to be enabled or disabled at will for this particular thread. Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>