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powerpc: Fix usage of _PAGE_RO in hugepage 

On some CPUs like the 8xx, _PAGE_RW hence _PAGE_WRITE is defined
as 0 and _PAGE_RO has to be set when a page is not writable

_PAGE_RO is defined by default in pte-common.h, however BOOK3S/64
doesn't include that file so _PAGE_RO has to be defined explicitly
in book3s/64/pgtable.h

Fixes: a7b9f671f2 ("powerpc32: adds handling of _PAGE_RO")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-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:
Christophe Leroy 2016-09-19 12:58:54 +02:00 committed by Michael Ellerman
parent af2e3a009e
commit 6b8cb66a6a
2 changed files with 9 additions and 0 deletions
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2
arch/powerpc/include/asm/book3s/64/pgtable.h
View File

@ -6,6 +6,8 @@
*/
#define _PAGE_BIT_SWAP_TYPE 0
#define _PAGE_RO 0
#define _PAGE_EXEC 0x00001 /* execute permission */
#define _PAGE_WRITE 0x00002 /* write access allowed */
#define _PAGE_READ 0x00004 /* read access allowed */

7
arch/powerpc/mm/hugetlbpage.c
View File

@ -1019,8 +1019,15 @@ int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
pte = READ_ONCE(*ptep);
mask = _PAGE_PRESENT | _PAGE_READ;
/*
* On some CPUs like the 8xx, _PAGE_RW hence _PAGE_WRITE is defined
* as 0 and _PAGE_RO has to be set when a page is not writable
*/
if (write)
mask |= _PAGE_WRITE;
else
mask |= _PAGE_RO;
if ((pte_val(pte) & mask) != mask)
return 0;