mirror of https://gitee.com/openkylin/linux.git
c812026c54
When running with a 52-bit userspace VA and a 48-bit kernel VA we offset ttbr1_el1 to allow the kernel pagetables with a 52-bit PTRS_PER_PGD to be used for both userspace and kernel. Moving on to a 52-bit kernel VA we no longer require this offset to ttbr1_el1 should we be running on a system with HW support for 52-bit VAs. This patch introduces conditional logic to offset_ttbr1 to query SYS_ID_AA64MMFR2_EL1 whenever 52-bit VAs are selected. If there is HW support for 52-bit VAs then the ttbr1 offset is skipped. We choose to read a system register rather than vabits_actual because offset_ttbr1 can be called in places where the kernel data is not actually mapped. Calls to offset_ttbr1 appear to be made from rarely called code paths so this extra logic is not expected to adversely affect performance. Signed-off-by: Steve Capper <steve.capper@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will@kernel.org> |
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