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3e6c69a058
Kernel Page Table Isolation (KPTI) is used to mitigate some speculation based security issues by ensuring that the kernel is not mapped when userspace is running but this approach is expensive and is incompatible with SPE. E0PD, introduced in the ARMv8.5 extensions, provides an alternative to this which ensures that accesses from userspace to the kernel's half of the memory map to always fault with constant time, preventing timing attacks without requiring constant unmapping and remapping or preventing legitimate accesses. Currently this feature will only be enabled if all CPUs in the system support E0PD, if some CPUs do not support the feature at boot time then the feature will not be enabled and in the unlikely event that a late CPU is the first CPU to lack the feature then we will reject that CPU. This initial patch does not yet integrate with KPTI, this will be dealt with in followup patches. Ideally we could ensure that by default we don't use KPTI on CPUs where E0PD is present. Signed-off-by: Mark Brown <broonie@kernel.org> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> [will: Fixed typo in Kconfig text] Signed-off-by: Will Deacon <will@kernel.org>
63 lines
2 KiB
C
63 lines
2 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* arch/arm64/include/asm/cpucaps.h
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*
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* Copyright (C) 2016 ARM Ltd.
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*/
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#ifndef __ASM_CPUCAPS_H
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#define __ASM_CPUCAPS_H
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#define ARM64_WORKAROUND_CLEAN_CACHE 0
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#define ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE 1
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#define ARM64_WORKAROUND_845719 2
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#define ARM64_HAS_SYSREG_GIC_CPUIF 3
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#define ARM64_HAS_PAN 4
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#define ARM64_HAS_LSE_ATOMICS 5
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#define ARM64_WORKAROUND_CAVIUM_23154 6
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#define ARM64_WORKAROUND_834220 7
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#define ARM64_HAS_NO_HW_PREFETCH 8
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#define ARM64_HAS_UAO 9
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#define ARM64_ALT_PAN_NOT_UAO 10
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#define ARM64_HAS_VIRT_HOST_EXTN 11
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#define ARM64_WORKAROUND_CAVIUM_27456 12
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#define ARM64_HAS_32BIT_EL0 13
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#define ARM64_HARDEN_EL2_VECTORS 14
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#define ARM64_HAS_CNP 15
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#define ARM64_HAS_NO_FPSIMD 16
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#define ARM64_WORKAROUND_REPEAT_TLBI 17
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#define ARM64_WORKAROUND_QCOM_FALKOR_E1003 18
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#define ARM64_WORKAROUND_858921 19
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#define ARM64_WORKAROUND_CAVIUM_30115 20
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#define ARM64_HAS_DCPOP 21
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#define ARM64_SVE 22
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#define ARM64_UNMAP_KERNEL_AT_EL0 23
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#define ARM64_HARDEN_BRANCH_PREDICTOR 24
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#define ARM64_HAS_RAS_EXTN 25
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#define ARM64_WORKAROUND_843419 26
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#define ARM64_HAS_CACHE_IDC 27
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#define ARM64_HAS_CACHE_DIC 28
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#define ARM64_HW_DBM 29
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#define ARM64_SSBD 30
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#define ARM64_MISMATCHED_CACHE_TYPE 31
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#define ARM64_HAS_STAGE2_FWB 32
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#define ARM64_HAS_CRC32 33
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#define ARM64_SSBS 34
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#define ARM64_WORKAROUND_1418040 35
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#define ARM64_HAS_SB 36
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#define ARM64_WORKAROUND_1165522 37
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#define ARM64_HAS_ADDRESS_AUTH_ARCH 38
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#define ARM64_HAS_ADDRESS_AUTH_IMP_DEF 39
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#define ARM64_HAS_GENERIC_AUTH_ARCH 40
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#define ARM64_HAS_GENERIC_AUTH_IMP_DEF 41
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#define ARM64_HAS_IRQ_PRIO_MASKING 42
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#define ARM64_HAS_DCPODP 43
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#define ARM64_WORKAROUND_1463225 44
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#define ARM64_WORKAROUND_CAVIUM_TX2_219_TVM 45
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#define ARM64_WORKAROUND_CAVIUM_TX2_219_PRFM 46
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#define ARM64_WORKAROUND_1542419 47
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#define ARM64_WORKAROUND_1319367 48
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#define ARM64_HAS_E0PD 49
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#define ARM64_NCAPS 50
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#endif /* __ASM_CPUCAPS_H */
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