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powerpc/mm: Use _PAGE_READ to indicate Read access

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This splits the _PAGE_RW bit into _PAGE_READ and _PAGE_WRITE. It also
removes the dependency on _PAGE_USER for implying read only. Few things
to note here is that, we have read implied with write and execute
permission. Hence we should always find _PAGE_READ set on hash pte
fault.

We still can't switch PROT_NONE to !(_PAGE_RWX). Auto numa depends on
marking a prot none pte _PAGE_WRITE. (For more details look at
b191f9b106 "mm: numa: preserve PTE write permissions across a NUMA
hinting fault")

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jeremy Kerr <jk@ozlabs.org>
Cc: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Aneesh Kumar K.V
2016-04-29 23:25:30 +10:00
committed by Michael Ellerman
parent ee3caed37d
commit c7d54842de
14 changed files with 49 additions and 37 deletions
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4
arch/powerpc/mm/hash64_64k.c
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@@ -77,7 +77,7 @@ int __hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid,
* also add _PAGE_COMBO
*/
new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED | _PAGE_COMBO;
if (access & _PAGE_RW)
if (access & _PAGE_WRITE)
new_pte |= _PAGE_DIRTY;
} while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));
@@ -251,7 +251,7 @@ int __hash_page_64K(unsigned long ea, unsigned long access,
* a write access.
*/
new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED;
if (access & _PAGE_RW)
if (access & _PAGE_WRITE)
new_pte |= _PAGE_DIRTY;
} while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));