| Message ID | 8097a1d32403ea47d076803e9070869badfe24bc.1534856426.git.christophe.leroy@c-s.fr (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 810e9f86f36f59f1d6f6710220c49afe0c705f38 |
| Headers | show |
| Series | powerpc/nohash: fix pte_access_permitted() | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | next/apply_patch Successfully applied |
| snowpatch_ozlabs/checkpatch | success | Test checkpatch on branch next |
| snowpatch_ozlabs/build-ppc64le | success | Test build-ppc64le on branch next |
| snowpatch_ozlabs/build-ppc64be | success | Test build-ppc64be on branch next |
| snowpatch_ozlabs/build-ppc64e | success | Test build-ppc64e on branch next |
| snowpatch_ozlabs/build-ppc32 | success | Test build-ppc32 on branch next |
Christophe Leroy <christophe.leroy@c-s.fr> writes: > 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. > Thanks for fixing this. I should have used the helper instead of opencoding it on nohash platforms. This is another reason why I was also suggesting we should avoid consolidating pte accessors across platforms and user accessors instead of opencoding. https://lore.kernel.org/lkml/87lgcusc6z.fsf@linux.vnet.ibm.com/T/#u Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> > 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> > --- > arch/powerpc/include/asm/nohash/pgtable.h | 9 +++------ > 1 file 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; > -- > 2.13.3
Le 21/08/2018 à 16:25, Aneesh Kumar K.V a écrit : > Christophe Leroy <christophe.leroy@c-s.fr> writes: > >> 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. >> > > Thanks for fixing this. I should have used the helper instead of > opencoding it on nohash platforms. This is another reason why I was also > suggesting we should avoid consolidating pte accessors across platforms > and user accessors instead of opencoding. I fully agree. I have opened a topic for that at https://github.com/linuxppc/linux/issues/177 Christophe > > https://lore.kernel.org/lkml/87lgcusc6z.fsf@linux.vnet.ibm.com/T/#u > > Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> > >> 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> >> --- >> arch/powerpc/include/asm/nohash/pgtable.h | 9 +++------ >> 1 file 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; >> -- >> 2.13.3
On Tue, 2018-08-21 at 13:03:23 UTC, Christophe Leroy wrote: > 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> Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/810e9f86f36f59f1d6f6710220c49a cheers
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;
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> --- arch/powerpc/include/asm/nohash/pgtable.h | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-)