linux-toradex.git/arch/powerpc/mm, branch v4.1.12

powerpc/mm: Recompute hash value after a failed update

2015-09-29T17:26:05+00:00

commit 36b35d5d807b7e57aff7d08e63de8b17731ee211 upstream.

If we had secondary hash flag set, we ended up modifying hash value in
the updatepp code path. Hence with a failed updatepp we will be using
a wrong hash value for the following hash insert. Fix this by
recomputing hash before insert.

Without this patch we can end up with using wrong slot number in linux
pte. That can result in us missing an hash pte update or invalidate
which can cause memory corruption or even machine check.

Fixes: 6d492ecc6489 ("powerpc/THP: Add code to handle HPTE faults for hugepages")
Signed-off-by: Aneesh Kumar K.V 
Reviewed-by: Paul Mackerras 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc/mm: Return NULL for not present hugetlb page

2015-05-12T01:04:29+00:00

We need to check whether pte is present in follow_huge_addr() and
properly return NULL if mapping is not present. Also use READ_ONCE
when dereferencing pte_t address.

Without this patch, we may wrongly return a zero pfn page in
follow_huge_addr().

Reviewed-by: David Gibson 
Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: Michael Ellerman

powerpc/thp: Serialize pmd clear against a linux page table walk.

2015-05-12T01:03:29+00:00

Serialize against find_linux_pte_or_hugepte() which does lock-less
lookup in page tables with local interrupts disabled. For huge pages it
casts pmd_t to pte_t. Since the format of pte_t is different from pmd_t
we want to prevent transit from pmd pointing to page table to pmd
pointing to huge page (and back) while interrupts are disabled.  We
clear pmd to possibly replace it with page table pointer in different
code paths. So make sure we wait for the parallel
find_linux_pte_or_hugepage() to finish.

Without this patch, a find_linux_pte_or_hugepte() running in parallel to
__split_huge_zero_page_pmd() or do_huge_pmd_wp_page_fallback() or
zap_huge_pmd() can run into the above issue. With
__split_huge_zero_page_pmd() and do_huge_pmd_wp_page_fallback() we clear
the hugepage pte before inserting the pmd entry with a regular pgtable
address. Such a clear need to wait for the parallel
find_linux_pte_or_hugepte() to finish.

With zap_huge_pmd(), we can run into issues, with a hugepage pte getting
zapped due to a MADV_DONTNEED while other cpu fault it in as small
pages.

Reported-by: Kirill A. Shutemov 
Signed-off-by: Aneesh Kumar K.V 
Reviewed-by: Kirill A. Shutemov 
Signed-off-by: Michael Ellerman

powerpc/mm: Fix build error with CONFIG_PPC_TRANSACTIONAL_MEM disabled

2015-04-23T07:42:14+00:00

This fix the below build error

arch/powerpc/mm/hash_utils_64.c: In function ‘flush_hash_hugepage’:
arch/powerpc/mm/hash_utils_64.c:1381:1: error: label at end of compound statement
 tm_abort:
 ^
make[1]: *** [arch/powerpc/mm/hash_utils_64.o] Error 1

Reported-by: Anshuman Khandual 
Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: Michael Ellerman

powerpc/mm/thp: Return pte address if we find trans_splitting.

2015-04-17T01:23:40+00:00

For THP that is marked trans splitting, we return the pte.
This require the callers to handle the pmd_trans_splitting scenario,
if they care. All the current callers are either looking at pfn or
write_ok, hence we don't need to update them.

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: Michael Ellerman

powerpc/mm/thp: Make page table walk safe against thp split/collapse

2015-04-17T01:23:39+00:00

We can disable a THP split or a hugepage collapse by disabling irq.
We do send IPI to all the cpus in the early part of split/collapse,
and disabling local irq ensure we don't make progress with
split/collapse. If the THP is getting split we return NULL from
find_linux_pte_or_hugepte(). For all the current callers it should be ok.
We need to be careful if we want to use returned pte_t pointer outside
the irq disabled region. W.r.t to THP split, the pfn remains the same,
but then a hugepage collapse will result in a pfn change. There are
few steps we can take to avoid a hugepage collapse.One way is to take page
reference inside the irq disable region. Other option is to take
mmap_sem so that a parallel collapse will not happen. We can also
disable collapse by taking pmd_lock. Another method used by kvm
subsystem is to check whether we had a mmu_notifer update in between
using mmu_notifier_retry().

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: Michael Ellerman

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/scottwood/linux into fixes

2015-04-17T01:22:51+00:00

Merge tag 'powerpc-4.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux

2015-04-16T18:53:32+00:00

Pull powerpc updates from Michael Ellerman:

- Numerous minor fixes, cleanups etc.

- More EEH work from Gavin to remove its dependency on device_nodes.

- Memory hotplug implemented entirely in the kernel from Nathan
Fontenot.

- Removal of redundant CONFIG_PPC_OF by Kevin Hao.

- Rewrite of VPHN parsing logic & tests from Greg Kurz.

- A fix from Nish Aravamudan to reduce memory usage by clamping
nodes_possible_map.

- Support for pstore on powernv from Hari Bathini.

- Removal of old powerpc specific byte swap routines by David Gibson.

- Fix from Vasant Hegde to prevent the flash driver telling you it was
flashing your firmware when it wasn't.

- Patch from Ben Herrenschmidt to add an OPAL heartbeat driver.

- Fix for an oops causing get/put_cpu_var() imbalance in perf by Jan
Stancek.

- Some fixes for migration from Tyrel Datwyler.

- A new syscall to switch the cpu endian by Michael Ellerman.

- Large series from Wei Yang to implement SRIOV, reviewed and acked by
Bjorn.

- A fix for the OPAL sensor driver from Cédric Le Goater.

- Fixes to get STRICT_MM_TYPECHECKS building again by Michael Ellerman.

- Large series from Daniel Axtens to make our PCI hooks per PHB rather
than per machine.

- Small patch from Sam Bobroff to explicitly abort non-suspended
transactions on syscalls, plus a test to exercise it.

- Numerous reworks and fixes for the 24x7 PMU from Sukadev Bhattiprolu.

- Small patch to enable the hard lockup detector from Anton Blanchard.

- Fix from Dave Olson for missing L2 cache information on some CPUs.

- Some fixes from Michael Ellerman to get Cell machines booting again.

- Freescale updates from Scott: Highlights include BMan device tree
nodes, an MSI erratum workaround, a couple minor performance
improvements, config updates, and misc fixes/cleanup.

* tag 'powerpc-4.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux: (196 commits)
powerpc/powermac: Fix build error seen with powermac smp builds
powerpc/pseries: Fix compile of memory hotplug without CONFIG_MEMORY_HOTREMOVE
powerpc: Remove PPC32 code from pseries specific find_and_init_phbs()
powerpc/cell: Fix iommu breakage caused by controller_ops change
powerpc/eeh: Fix crash in eeh_add_device_early() on Cell
powerpc/perf: Cap 64bit userspace backtraces to PERF_MAX_STACK_DEPTH
powerpc/perf/hv-24x7: Fail 24x7 initcall if create_events_from_catalog() fails
powerpc/pseries: Correct memory hotplug locking
powerpc: Fix missing L2 cache size in /sys/devices/system/cpu
powerpc: Add ppc64 hard lockup detector support
oprofile: Disable oprofile NMI timer on ppc64
powerpc/perf/hv-24x7: Add missing put_cpu_var()
powerpc/perf/hv-24x7: Break up single_24x7_request
powerpc/perf/hv-24x7: Define update_event_count()
powerpc/perf/hv-24x7: Whitespace cleanup
powerpc/perf/hv-24x7: Define add_event_to_24x7_request()
powerpc/perf/hv-24x7: Rename hv_24x7_event_update
powerpc/perf/hv-24x7: Move debug prints to separate function
powerpc/perf/hv-24x7: Drop event_24x7_request()
powerpc/perf/hv-24x7: Use pr_devel() to log message
...

Conflicts:
tools/testing/selftests/powerpc/Makefile
tools/testing/selftests/powerpc/tm/Makefile

powerpc/hugetlb: Call mm_dec_nr_pmds() in hugetlb_free_pmd_range()

2015-04-15T20:24:22+00:00

Commit dc6c9a35b66b5 ("mm: account pmd page tables to the process")
added a counter that is incremented whenever a PMD is allocated and
decremented whenever a PMD is freed.  For hugepages on PPC, common code
is used to allocated PMDs, but arch-specific code is used to free PMDs.

This results in kernel output such as "BUG: non-zero nr_pmds on freeing
mm: 1" when using hugepages.

Update the PPC hugepage PMD freeing code to decrement the count, just
as the above commit did for free_pmd_range().

Fixes: dc6c9a35b66b5 ("mm: account pmd page tables to the process")
Signed-off-by: Scott Wood 
Reviewed-by: Aneesh Kumar K.V 
Cc: stable@vger.kernel.org # 4.0.x

mm: expose arch_mmap_rnd when available

2015-04-14T23:49:05+00:00

When an architecture fully supports randomizing the ELF load location,
a per-arch mmap_rnd() function is used to find a randomized mmap base.
In preparation for randomizing the location of ET_DYN binaries
separately from mmap, this renames and exports these functions as
arch_mmap_rnd(). Additionally introduces CONFIG_ARCH_HAS_ELF_RANDOMIZE
for describing this feature on architectures that support it
(which is a superset of ARCH_BINFMT_ELF_RANDOMIZE_PIE, since s390
already supports a separated ET_DYN ASLR from mmap ASLR without the
ARCH_BINFMT_ELF_RANDOMIZE_PIE logic).

Signed-off-by: Kees Cook 
Cc: Hector Marco-Gisbert 
Cc: Russell King 
Reviewed-by: Ingo Molnar 
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Ralf Baechle 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Michael Ellerman 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Alexander Viro 
Cc: Oleg Nesterov 
Cc: Andy Lutomirski 
Cc: "David A. Long" 
Cc: Andrey Ryabinin 
Cc: Arun Chandran 
Cc: Yann Droneaud 
Cc: Min-Hua Chen 
Cc: Paul Burton 
Cc: Alex Smith 
Cc: Markos Chandras 
Cc: Vineeth Vijayan 
Cc: Jeff Bailey 
Cc: Michael Holzheu 
Cc: Ben Hutchings 
Cc: Behan Webster 
Cc: Ismael Ripoll 
Cc: Jan-Simon Mller 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds