arm64: fix R/O permissions of FDT mapping

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The mapping permissions of the FDT are set to 'PAGE_KERNEL | PTE_RDONLY'
in an attempt to map the FDT as read-only. However, not only does this
break at build time under STRICT_MM_TYPECHECKS (since the two terms are
of different types in that case), it also results in both the PTE_WRITE
and PTE_RDONLY attributes to be set, which means the region is still
writable under ARMv8.1 DBM (and an attempted write will simply clear the
PT_RDONLY bit).

So instead, define PAGE_KERNEL_RO (which already has an established
meaning across architectures) and use that instead.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

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Ard Biesheuvel 2015-11-09 09:55:46 +01:00 • committed by Catalin Marinas

parent b219545e96

commit fb226c3d7c

2 changed files with 2 additions and 1 deletions

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1

arch/arm64/include/asm/pgtable.h

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2

arch/arm64/mm/mmu.c

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