arm64: Implement arch-specific pte_access_permitted()

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The generic pte_access_permitted() implementation only checks for
pte_present() (together with the write permission where applicable).
However, for both kernel ptes and PROT_NONE mappings pte_present() also
returns true on arm64 even though such mappings are not user accessible.
Additionally, arm64 now supports execute-only user permission
(PROT_EXEC) which is implemented by clearing the PTE_USER bit.

With this patch the arm64 implementation of pte_access_permitted()
checks for the PTE_VALID and PTE_USER bits together with writable access
if applicable.

Cc: <stable@vger.kernel.org>
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

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Catalin Marinas 2017-10-26 18:36:47 +01:00 • committed by Will Deacon

parent d7b1d22d38

commit 6218f96c58

1 changed files with 14 additions and 0 deletions

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arch/arm64/include/asm/pgtable.h

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