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| author | Christophe Leroy <christophe.leroy@c-s.fr> | 2018-08-21 16:03:23 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-08-23 05:15:58 +0300 |
| commit | 810e9f86f36f59f1d6f6710220c49afe0c705f38 (patch) | |
| tree | ff4a4ce016185ec171cd06466b8dec7b039bb137 /arch | |
| parent | 2ea62630681027c455117aa471ea3ab8bb099ead (diff) | |
| download | linux-810e9f86f36f59f1d6f6710220c49afe0c705f38.tar.xz | |
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.h | 9 |
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; |