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authorChristophe Leroy <christophe.leroy@c-s.fr>2018-08-21 13:03:23 +0000
committerMichael Ellerman <mpe@ellerman.id.au>2018-08-23 12:15:58 +1000
commit810e9f86f36f59f1d6f6710220c49afe0c705f38 (patch)
treeff4a4ce016185ec171cd06466b8dec7b039bb137 /arch
parent2ea62630681027c455117aa471ea3ab8bb099ead (diff)
download96b-common-810e9f86f36f59f1d6f6710220c49afe0c705f38.tar.gz
powerpc/nohash: fix pte_access_permitted()
Commit 5769beaf180a8 ("powerpc/mm: Add proper pte access check helper for other platforms") replaced generic pte_access_permitted() by an arch specific one. The generic one is defined as (pte_present(pte) && (!(write) || pte_write(pte))) The arch specific one is open coded checking that _PAGE_USER and _PAGE_WRITE (_PAGE_RW) flags are set, but lacking to check that _PAGE_RO and _PAGE_PRIVILEGED are unset, leading to a useless test on targets like the 8xx which defines _PAGE_RW and _PAGE_USER as 0. Commit 5fa5b16be5b31 ("powerpc/mm/hugetlb: Use pte_access_permitted for hugetlb access check") replaced some tests performed with pte helpers by a call to pte_access_permitted(), leading to the same issue. This patch rewrites powerpc/nohash pte_access_permitted() using pte helpers. Fixes: 5769beaf180a8 ("powerpc/mm: Add proper pte access check helper for other platforms") Fixes: 5fa5b16be5b31 ("powerpc/mm/hugetlb: Use pte_access_permitted for hugetlb access check") Cc: stable@vger.kernel.org # v4.15+ Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/include/asm/nohash/pgtable.h9
1 files changed, 3 insertions, 6 deletions
diff --git a/arch/powerpc/include/asm/nohash/pgtable.h b/arch/powerpc/include/asm/nohash/pgtable.h
index 2160be2e4339..b321c82b3624 100644
--- a/arch/powerpc/include/asm/nohash/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/pgtable.h
@@ -51,17 +51,14 @@ static inline int pte_present(pte_t pte)
#define pte_access_permitted pte_access_permitted
static inline bool pte_access_permitted(pte_t pte, bool write)
{
- unsigned long pteval = pte_val(pte);
/*
* A read-only access is controlled by _PAGE_USER bit.
* We have _PAGE_READ set for WRITE and EXECUTE
*/
- unsigned long need_pte_bits = _PAGE_PRESENT | _PAGE_USER;
-
- if (write)
- need_pte_bits |= _PAGE_WRITE;
+ if (!pte_present(pte) || !pte_user(pte) || !pte_read(pte))
+ return false;
- if ((pteval & need_pte_bits) != need_pte_bits)
+ if (write && !pte_write(pte))
return false;
return true;