4.8-stable review patch. If anyone has any objections, please let me know.
------------------
From: Christophe Leroy <christophe.leroy@xxxxxx>
commit 6b8cb66a6a7cc182b47da6a0a1d4e5da324c0695 upstream.
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: a7b9f671f2d14 ("powerpc32: adds handling of _PAGE_RO")
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/include/asm/book3s/64/pgtable.h | 2 ++
arch/powerpc/mm/hugetlbpage.c | 7 +++++++
2 files changed, 9 insertions(+)
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -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 */
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -1019,8 +1019,15 @@ int gup_hugepte(pte_t *ptep, unsigned lo
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;
--
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