path: root/arch/arm64/Kconfig
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authorSteve Capper <steve.capper@arm.com>2018-12-06 22:50:40 +0000
committerWill Deacon <will.deacon@arm.com>2018-12-10 18:42:17 +0000
commita96a33b1ca57dbea4285893dedf290aeb8eb090b (patch)
tree411dca8ab198c3d136b91d3217438c9b3d55ef76 /arch/arm64/Kconfig
parentarm64: mm: Offset TTBR1 to allow 52-bit PTRS_PER_PGD (diff)
arm64: mm: Prevent mismatched 52-bit VA support
For cases where there is a mismatch in ARMv8.2-LVA support between CPUs we have to be careful in allowing secondary CPUs to boot if 52-bit virtual addresses have already been enabled on the boot CPU. This patch adds code to the secondary startup path. If the boot CPU has enabled 52-bit VAs then ID_AA64MMFR2_EL1 is checked to see if the secondary can also enable 52-bit support. If not, the secondary is prevented from booting and an error message is displayed indicating why. Technically this patch could be implemented using the cpufeature code when considering 52-bit userspace support. However, we employ low level checks here as the cpufeature code won't be able to run if we have mismatched 52-bit kernel va support. Signed-off-by: Steve Capper <steve.capper@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
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