powerpc/mm/subpage: Clear RWX bit to indicate no access

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Subpage protection used to depend on the _PAGE_USER bit to implement no
access mode. This patch switches that to use _PAGE_RWX. We clear Read,
Write and Execute access from the pte instead of clearing _PAGE_USER
now. This was done so that we can switch to _PAGE_PRIVILEGED in a later
patch.

subpage_protection() returns pte bits that need to be cleared. Instead
of updating the interface to handle no-access in a separate way, it
appears simpler to clear RWX acecss to indicate no access.

We still don't insert hash ptes for no access implied by !_PAGE_RWX.
Hence we should not get PROT_FAULT with change.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

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Aneesh Kumar K.V 2016-04-29 23:25:31 +10:00 • committed by Michael Ellerman

parent c7d54842de

commit 73a1441a9b

1 changed files with 8 additions and 3 deletions

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arch/powerpc/mm/hash_utils_64.c

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