| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.8 113/125] powerpc: Fix usage of _PAGE_RO in hugepage | Date | Sat, 29 Oct 2016 09:50:31 -0400 |
| |
4.8-stable review patch. If anyone has any objections, please let me know.
------------------
From: Christophe Leroy <christophe.leroy@c-s.fr>
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@c-s.fr> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- 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;
|