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Commit 6b8cb66a authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

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: a7b9f671 ("powerpc32: adds handling of _PAGE_RO")
Signed-off-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent af2e3a00

arch/powerpc/include/asm/book3s/64/pgtable.h

+2 −0
Original line number Diff line number Diff line
@@ -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 */

arch/powerpc/mm/hugetlbpage.c

+7 −0
Original line number Diff line number Diff line
@@ -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;