arm64: add PTE_UXN/PTE_WRITE to SWAPPER_*_FLAGS

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With PIE enabled, the swapper PTEs would have a Permission Indirection Index
(PIIndex) of 0. A PIIndex of 0 is not currently used by any other PTEs.

To avoid using index 0 specifically for the swapper PTEs, mark them as
PTE_UXN and PTE_WRITE, so that they map to a PAGE_KERNEL_EXEC equivalent.

This also adds PTE_WRITE to KPTI_NG_PTE_FLAGS, which was tested by booting
with kpti=on.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20230606145859.697944-12-joey.gouly@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

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This commit is contained in:

Joey Gouly 2023-06-06 15:58:50 +01:00 • committed by Catalin Marinas

parent 8ef67c67e6

commit f0af339fc4

3 changed files with 10 additions and 10 deletions

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8

arch/arm64/include/asm/kernel-pgtable.h

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arch/arm64/kernel/head.S

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arch/arm64/mm/proc.S

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