Commit Graph

203 Commits

Author SHA1 Message Date
Aneesh Kumar K.V
11a6f6abd7 powerpc/mm: Move radix/hash common data structures to book3s64 headers
Start moving code that is generic between radix and hash to book3s64
specific headers from the book3s64 hash specific one.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-01 18:32:37 +10:00
Aneesh Kumar K.V
33d336d986 powerpc/mm: Use generic version of ptep_clear_flush_young()
The radix variant is going to require a flush_tlb_range(). With
flush_tlb_range() added, ptep_clear_flush_young() is the same as the
generic version. So drop the powerpc specific variant.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-01 18:32:36 +10:00
Aneesh Kumar K.V
ff844b741e powerpc/mm: Use generic version of pmdp_clear_flush_young()
The radix variant is going to require a flush_pmd_tlb_range(). With
flush_pmd_tlb_range() added, pmdp_clear_flush_young() is the same as the
generic version. So drop the powerpc specific variant.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-01 18:32:35 +10:00
Aneesh Kumar K.V
30bda41aba powerpc/mm: Drop WIMG in favour of new constants
PowerISA 3.0 introduces two pte bits with the below meaning for radix:
  00 -> Normal Memory
  01 -> Strong Access Order (SAO)
  10 -> Non idempotent I/O (Cache inhibited and guarded)
  11 -> Tolerant I/O (Cache inhibited)

We drop the existing WIMG bits in the Linux page table in favour of the
above constants. We loose _PAGE_WRITETHRU with this conversion. We only
use writethru via pgprot_cached_wthru() which is used by
fbdev/controlfb.c which is Apple control display and also PPC32.

With respect to _PAGE_COHERENCE, we have been marking hpte always
coherent for some time now. htab_convert_pte_flags() always added
HPTE_R_M.

NOTE: KVM changes need closer review.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-01 18:32:33 +10:00
Aneesh Kumar K.V
e58e87adc8 powerpc/mm: Update _PAGE_KERNEL_RO
PS3 had used a PPP bit hack to implement a read only mapping in the
kernel area. Since we are bolting the ioremap area, it used the pte
flags _PAGE_PRESENT | _PAGE_USER to get a PPP value of 0x3 there by
resulting in a read only mapping. This means the area can be accessed by
user space, but kernel will never return such an address to user space.

But we can do better by implementing a read only kernel mapping using
PPP bits 0b110.

This also allows us to do read only kernel mapping for radix in later
patches.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-01 18:32:30 +10:00
Aneesh Kumar K.V
96270b1fc2 powerpc/mm: Remove RPN_SHIFT and RPN_SIZE
PTE_RPN_SHIFT is actually page size dependent. Even though PowerISA 3.0
expects only the lower 12 bits to be zero, we will always find the pages
to be PAGE_SHIFT aligned. In case of hash config, this also allows us to
use the additional 3 bits to track pte specific information. We need
to make sure we use these bits only for hash specific pte flags.

For both 4K and 64K config, pte now can hold 57 bits address.

Inorder to keep things simpler, drop PTE_RPN_SHIFT and PTE_RPN_SIZE and
specify the 57 bit detail explicitly.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-01 18:32:29 +10:00
Aneesh Kumar K.V
ac29c64089 powerpc/mm: Replace _PAGE_USER with _PAGE_PRIVILEGED
_PAGE_PRIVILEGED means the page can be accessed only by the kernel. This
is done to keep pte bits similar to PowerISA 3.0 Radix PTE format. User
pages are now marked by clearing _PAGE_PRIVILEGED bit.

Previously we allowed the kernel to have a privileged page in the lower
address range (USER_REGION). With this patch such access is denied.

We also prevent a kernel access to a non-privileged page in higher
address range (ie, REGION_ID != 0).

Both the above access scenarios should never happen.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jeremy Kerr <jk@ozlabs.org>
Cc: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-01 18:32:26 +10:00
Aneesh Kumar K.V
e7bfc462d3 powerpc/mm: Use pte_user() instead of open coding
We have a common declaration in pte-common.h Add a book3s specific one
and switch to pte_user() in callchain.c. In a subsequent patch we will
switch _PAGE_USER to _PAGE_PRIVILEGED in the book3s version only.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-01 18:32:25 +10:00
Aneesh Kumar K.V
c7d54842de powerpc/mm: Use _PAGE_READ to indicate Read access
This splits the _PAGE_RW bit into _PAGE_READ and _PAGE_WRITE. It also
removes the dependency on _PAGE_USER for implying read only. Few things
to note here is that, we have read implied with write and execute
permission. Hence we should always find _PAGE_READ set on hash pte
fault.

We still can't switch PROT_NONE to !(_PAGE_RWX). Auto numa depends on
marking a prot none pte _PAGE_WRITE. (For more details look at
b191f9b106 "mm: numa: preserve PTE write permissions across a NUMA
hinting fault")

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jeremy Kerr <jk@ozlabs.org>
Cc: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-01 18:32:21 +10:00
Michael Ellerman
ee3caed37d powerpc/mm: Use pte_raw() in pte_same()/pmd_same()
We can avoid doing endian conversions by using pte_raw() in pxx_same().
The swap of the constant (_PAGE_HPTEFLAGS) should be done at compile
time by the compiler.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-01 18:32:19 +10:00
Aneesh Kumar K.V
5dc1ef858c powerpc/mm: Use big endian Linux page tables for book3s 64
Traditionally Power server machines have used the Hashed Page Table MMU
mode. In this mode Linux manages its own tree of nested page tables,
aka. "the Linux page tables", which are not used by the hardware
directly, and software loads translations into the hash page table for
use by the hardware.

Power ISA 3.0 defines a new MMU mode, known as Radix Tree Translation,
where the hardware can directly operate on the Linux page tables.
However the hardware requires that the page tables be in big endian
format.

To accommodate this, switch the pgtable types to __be64 and add
appropriate endian conversions.

Because we will be supporting a single kernel binary that boots using
either radix or hash mode, we always store the Linux page tables big
endian, even in hash mode where they are not actually used by the
hardware.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[mpe: Fix sparse errors, flesh out change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-01 18:32:18 +10:00
Aneesh Kumar K.V
4bece39b50 powerpc/mm: Drop PTE_ATOMIC_UPDATES from pmd_hugepage_update()
pmd_hugepage_update() is inside #ifdef CONFIG_TRANSPARENT_HUGEPAGE. THP
can only be enabled if PPC_BOOK3S_64=y && PPC_64K_PAGES=y, aka. hash64.

On hash64 we always define PTE_ATOMIC_UPDATES to 1, meaning the #ifdef
in pmd_hugepage_update() is unnecessary, so drop it.

That is also the only use of PTE_ATOMIC_UPDATES in any of the hash code,
meaning we no longer need to #define it at all in the hash headers.

Note it's still #defined and used in the nohash code.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-01 18:32:15 +10:00
Aneesh Kumar K.V
ee3b93ebfb powerpc/mm: Move hash64 tlbflush code into a new header
No code changes.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-03-03 21:19:39 +11:00
Aneesh Kumar K.V
f64e8084c9 powerpc/mm: Move hash related mmu-*.h headers to book3s/
No code changes.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-03-03 21:19:21 +11:00
Aneesh Kumar K.V
368ced78e6 powerpc/mm: Switch book3s 64 with 64K page size to 4 level page table
This is needed so that we can support both hash and radix page table
using single kernel. Radix kernel uses a 4 level table.

We now use physical address in upper page table tree levels. Even though
they are aligned to their size, for the masked bits we use the
bit positions as per PowerISA 3.0.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-03-03 21:18:28 +11:00
Aneesh Kumar K.V
ae9a71afa4 powerpc/mm: Don't have conditional defines for real_pte_t
We remove real_pte_t out of STRICT_MM_TYPESCHECK.

Reviewed-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-03-03 16:47:02 +11:00
Paul Mackerras
8daf51f55f powerpc/mm/book3s-64: Expand the real page number field of the Linux PTE
Now that other PTE fields have been moved out of the way, we can
expand the RPN field of the PTE on 64-bit Book 3S systems and align
it with the RPN field in the radix PTE format used by PowerISA v3.0
CPUs in radix mode.  For 64k page size, this means we need to move
the _PAGE_COMBO and _PAGE_4K_PFN bits.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-02-29 20:34:41 +11:00
Paul Mackerras
e726202f06 powerpc/mm/book3s-64: Move software-used bits in PTE
This moves the _PAGE_SPECIAL and _PAGE_SOFT_DIRTY bits in the Linux
PTE on 64-bit Book 3S systems to bit positions which are designated
for software use in the radix PTE format used by PowerISA v3.0 CPUs
in radix mode.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-02-29 20:34:40 +11:00
Paul Mackerras
c915df162d powerpc/mm/book3s-64: Shuffle read, write, execute and user bits in PTE
This moves the _PAGE_EXEC, _PAGE_RW and _PAGE_USER bits around in
the Linux PTE on 64-bit Book 3S systems to correspond with the bit
positions used in radix mode by PowerISA v3.0 CPUs.  This also adds
a _PAGE_READ bit corresponding to the read permission bit in the
radix PTE.  _PAGE_READ is currently unused but could possibly be used
in future to improve pte_protnone().

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-02-29 20:34:40 +11:00
Paul Mackerras
a9d4996df1 powerpc/mm/book3s-64: Move HPTE-related bits in PTE to upper end
This moves the _PAGE_HASHPTE, _PAGE_F_GIX and _PAGE_F_SECOND fields in
the Linux PTE on 64-bit Book 3S systems to the most significant byte.
Of the 5 bits, one is a software-use bit and the other four are
reserved bit positions in the PowerISA v3.0 radix PTE format.
Using these bits is OK because these bits are all to do with tracking
the HPTE(s) associated with the Linux PTE, and therefore won't be
needed in radix mode.  This frees up bit positions in the lower two
bytes.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-02-29 20:34:39 +11:00
Paul Mackerras
84c957560a powerpc/mm/book3s-64: Move _PAGE_PTE to 2nd most significant bit
This changes _PAGE_PTE for 64-bit Book 3S processors from 0x1 to
0x4000_0000_0000_0000, because that bit is used as the L (leaf)
bit by PowerISA v3.0 CPUs in radix mode.  The "leaf" bit indicates
that the PTE points to a page directly rather than another radix
level, which is what the _PAGE_PTE bit means.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-02-29 20:34:39 +11:00
Paul Mackerras
849f86a630 powerpc/mm/book3s-64: Move _PAGE_PRESENT to the most significant bit
This changes _PAGE_PRESENT for 64-bit Book 3S processors from 0x2 to
0x8000_0000_0000_0000, because that is where PowerISA v3.0 CPUs in
radix mode will expect to find it.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-02-29 20:34:39 +11:00
Paul Mackerras
c61a884312 powerpc/mm/book3s-64: Use physical addresses in upper page table tree levels
This changes the Linux page tables to store physical addresses
rather than kernel virtual addresses in the upper levels of the
tree (pgd, pud and pmd) for 64-bit Book 3S machines.

This also changes the hugepd pointers used to implement hugepages
when the base page size is 4k to store physical addresses rather than
virtual addresses (again just for 64-bit Book3S machines).

This frees up some high order bits, and will be needed with
PowerISA v3.0 machines which read the page table tree in hardware
in radix mode.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-02-29 20:34:34 +11:00
Paul Mackerras
f1a9ae034a powerpc/mm/book3s-64: Free up 7 high-order bits in the Linux PTE
This frees up bits 57-63 in the Linux PTE on 64-bit Book 3S machines.
In the 4k page case, this is done just by reducing the size of the
RPN field to 39 bits, giving 51-bit real addresses.  In the 64k page
case, we had 10 unused bits in the middle of the PTE, so this moves
the RPN field down 10 bits to make use of those unused bits.  This
means the RPN field is now 3 bits larger at 37 bits, giving 53-bit
real addresses in the normal case, or 49-bit real addresses for the
special 4k PFN case.

We are doing this in order to be able to move some other PTE bits
into the positions where PowerISA V3.0 processors will expect to
find them in radix-tree mode.  Ultimately we will be able to move
the RPN field to lower bit positions and make it larger.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-02-27 21:06:57 +11:00
Paul Mackerras
1ec3f93710 powerpc/mm/book3s-64: Clean up some obsolete or misleading comments
No code changes.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-02-27 21:06:57 +11:00
Aneesh Kumar K.V
c777e2a8b6 powerpc/mm: Fix Multi hit ERAT cause by recent THP update
With ppc64 we use the deposited pgtable_t to store the hash pte slot
information. We should not withdraw the deposited pgtable_t without
marking the pmd none. This ensure that low level hash fault handling
will skip this huge pte and we will handle them at upper levels.

Recent change to pmd splitting changed the above in order to handle the
race between pmd split and exit_mmap. The race is explained below.

Consider following race:

		CPU0				CPU1
shrink_page_list()
  add_to_swap()
    split_huge_page_to_list()
      __split_huge_pmd_locked()
        pmdp_huge_clear_flush_notify()
	// pmd_none() == true
					exit_mmap()
					  unmap_vmas()
					    zap_pmd_range()
					      // no action on pmd since pmd_none() == true
	pmd_populate()

As result the THP will not be freed. The leak is detected by check_mm():

	BUG: Bad rss-counter state mm:ffff880058d2e580 idx:1 val:512

The above required us to not mark pmd none during a pmd split.

The fix for ppc is to clear the huge pte of _PAGE_USER, so that low
level fault handling code skip this pte. At higher level we do take ptl
lock. That should serialze us against the pmd split. Once the lock is
acquired we do check the pmd again using pmd_same. That should always
return false for us and hence we should retry the access. We do the
pmd_same check in all case after taking plt with
THP (do_huge_pmd_wp_page, do_huge_pmd_numa_page and
huge_pmd_set_accessed)

Also make sure we wait for irq disable section in other cpus to finish
before flipping a huge pte entry with a regular pmd entry. Code paths
like find_linux_pte_or_hugepte depend on irq disable to get
a stable pte_t pointer. A parallel thp split need to make sure we
don't convert a pmd pte to a regular pmd entry without waiting for the
irq disable section to finish.

Fixes: eef1b3ba05 ("thp: implement split_huge_pmd()")
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-02-15 21:10:04 +11:00
Aneesh Kumar K.V
2d19fc6395 powerpc/mm: Fixup _HPAGE_CHG_MASK
This was wrongly updated by commit 7aa9a23c69 ("powerpc, thp: remove
infrastructure for handling splitting PMDs") during the last merge
window. Fix it up.

This could lead to incorrect behaviour in THP and/or mprotect(), at a
minimum.

Fixes: 7aa9a23c69 ("powerpc, thp: remove infrastructure for handling splitting PMDs")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-01-28 23:49:43 +11:00
Stephen Rothwell
0e2bce7411 powerpc: Remove newly added extra definition of pmd_dirty
Commit d5d6a443b2 ("arch/powerpc/include/asm/pgtable-ppc64.h:
add pmd_[dirty|mkclean] for THP") added a new identical definition
of pmd_dirty(). Remove it again.

Cc: Minchan Kim <minchan@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-01-21 14:12:54 +11:00
Minchan Kim
d5d6a443b2 arch/powerpc/include/asm/pgtable-ppc64.h: add pmd_[dirty|mkclean] for THP
MADV_FREE needs pmd_dirty and pmd_mkclean for detecting recent overwrite
of the contents since MADV_FREE syscall is called for THP page.

This patch adds pmd_dirty and pmd_mkclean for THP page MADV_FREE
support.

Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Shaohua Li <shli@kernel.org>
Cc: <yalin.wang2010@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Gang <gang.chen.5i5j@gmail.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Daniel Micay <danielmicay@gmail.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Helge Deller <deller@gmx.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Jason Evans <je@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mika Penttil <mika.penttila@nextfour.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rik van Riel <riel@redhat.com>
Cc: Roland Dreier <roland@kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Shaohua Li <shli@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 17:56:32 -08:00
Kirill A. Shutemov
7aa9a23c69 powerpc, thp: remove infrastructure for handling splitting PMDs
With new refcounting we don't need to mark PMDs splitting.  Let's drop
code to handle this.

pmdp_splitting_flush() is not needed too: on splitting PMD we will do
pmdp_clear_flush() + set_pte_at().  pmdp_clear_flush() will do IPI as
needed for fast_gup.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15 17:56:32 -08:00
Hugh Dickins
2f10f1a788 powerpc/mm: fix _PAGE_SWP_SOFT_DIRTY breaking swapoff
Swapoff after swapping hangs on the G5, when CONFIG_CHECKPOINT_RESTORE=y
but CONFIG_MEM_SOFT_DIRTY is not set.  That's because the non-zero
_PAGE_SWP_SOFT_DIRTY bit, added by CONFIG_HAVE_ARCH_SOFT_DIRTY=y, is not
discounted when CONFIG_MEM_SOFT_DIRTY is not set: so swap ptes cannot be
recognized.

(I suspect that the peculiar dependence of HAVE_ARCH_SOFT_DIRTY on
CHECKPOINT_RESTORE in arch/powerpc/Kconfig comes from an incomplete
attempt to solve this problem.)

It's true that the relationship between CONFIG_HAVE_ARCH_SOFT_DIRTY and
and CONFIG_MEM_SOFT_DIRTY is too confusing, and it's true that swapoff
should be made more robust; but nevertheless, fix up the powerpc ifdefs
as x86_64 and s390 (which met the same problem) have them, defining the
bits as 0 if CONFIG_MEM_SOFT_DIRTY is not set.

Fixes: 7207f43665 ("powerpc/mm: Add page soft dirty tracking")
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-01-12 11:03:53 +11:00
Aneesh Kumar K.V
44734f23de powerpc/mm: Fix _PAGE_PTE breaking swapoff
Core kernel expects swp_entry_t to consist of only swap type and swap
offset. We should not leak pte bits into swp_entry_t. This breaks
swapoff which use the swap type and offset to build a swp_entry_t and
later compare that to the swp_entry_t obtained from linux page table
pte. Leaking pte bits into swp_entry_t breaks that comparison and
results in us looping in try_to_unuse.

The stack trace can be anywhere below try_to_unuse() in mm/swapfile.c,
since swapoff is circling around and around that function, reading from
each used swap block into a page, then trying to find where that page
belongs, looking at every non-file pte of every mm that ever swapped.

Fixes: 6a119eae94 ("powerpc/mm: Add a _PAGE_PTE bit")
Reported-by: Hugh Dickins <hughd@google.com>
Suggested-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-01-12 11:02:35 +11:00
Laurent Dufour
7207f43665 powerpc/mm: Add page soft dirty tracking
User space checkpoint and restart tool (CRIU) needs the page's change
to be soft tracked. This allows to do a pre checkpoint and then dump
only touched pages.

This is done by using a newly assigned PTE bit (_PAGE_SOFT_DIRTY) when
the page is backed in memory, and a new _PAGE_SWP_SOFT_DIRTY bit when
the page is swapped out.

To introduce a new PTE _PAGE_SOFT_DIRTY bit value common to hash 4k
and hash 64k pte, the bits already defined in hash-*4k.h should be
shifted left by one.

The _PAGE_SWP_SOFT_DIRTY bit is dynamically put after the swap type in
the swap pte. A check is added to ensure that the bit is not
overwritten by _PAGE_HPTEFLAGS.

Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
CC: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-17 22:40:58 +11:00
Aneesh Kumar K.V
4d9057c39a powerpc/mm: Don't hardcode the hash pte slot shift
Use the #define instead of open-coding the same

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 15:19:15 +11:00
Aneesh Kumar K.V
62607bc64c powerpc/mm: Don't hardcode page table size
pte and pmd table size are dependent on config items. Don't
hard code the same. This make sure we use the right value
when masking pmd entries and also while checking pmd_bad

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 15:19:15 +11:00
Aneesh Kumar K.V
6a119eae94 powerpc/mm: Add a _PAGE_PTE bit
For a pte entry we will have _PAGE_PTE set. Our pte page
address have a minimum alignment requirement of HUGEPD_SHIFT_MASK + 1.
We use the lower 7 bits to indicate hugepd. ie.

For pmd and pgd we can find:
1) _PAGE_PTE set pte -> indicate PTE
2) bits [2..6] non zero -> indicate hugepd.
   They also encode the size. We skip bit 1 (_PAGE_PRESENT).
3) othewise pointer to next table.

Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 15:19:14 +11:00
Aneesh Kumar K.V
e34aa03ca4 powerpc/mm: Move THP headers around
We support THP only with book3s_64 and 64K page size. Move
THP details to hash64-64k.h to clarify the same.

Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 15:19:14 +11:00
Aneesh Kumar K.V
26a344aea4 powerpc/mm: Move hugetlb related headers
W.r.t hugetlb, we support two format for pmd. With book3s_64 and
64K linux page size, we can have pte at the pmd level. Hence we
don't need to support hugepd there. For everything else hugepd
is supported and pmd_huge is (0).

Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 15:19:13 +11:00
Aneesh Kumar K.V
c6a3c495f0 powerpc/mm: Add helper for converting pte bit to hpte bits
Instead of open coding it in multiple code paths, export the helper
and add more documentation. Also make sure we don't make assumption
regarding pte bit position

Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 15:19:12 +11:00
Aneesh Kumar K.V
89ff725051 powerpc/mm: Convert __hash_page_64K to C
Convert from asm to C

Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 15:19:11 +11:00
Aneesh Kumar K.V
227fdbee5a powerpc/mm: Increase the width of #define
No real change, only style changes

Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 15:19:11 +11:00
Aneesh Kumar K.V
506b863c68 powerpc/mm: Remove pte_val usage for the second half of pgtable_t
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 15:19:10 +11:00
Aneesh Kumar K.V
bf680d5160 powerpc/mm: Don't track subpage valid bit in pte_t
This free up 11 bits in pte_t. In the later patch we also change
the pte_t format so that we can start supporting migration pte
at pmd level. We now track 4k subpage valid bit as below

If we have _PAGE_COMBO set, we override the _PAGE_F_GIX_SHIFT
and _PAGE_F_SECOND. Together we have 4 bits, each of them
used to indicate whether any of the 4 4k subpage in that group
is valid. ie,

[ group 1 bit ]   [ group 2 bit ]  ..... [ group 4 ]
[ subpage 1 - 4]  [ subpage 5- 8]  ..... [ subpage 13 - 16]

We still track each 4k subpage slot number and secondary hash
information in the second half of pgtable_t. Removing the subpage
tracking have some significant overhead on aim9 and ebizzy benchmark and
to support THP with 4K subpage, we do need a pgtable_t of 4096 bytes.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 15:19:10 +11:00
Aneesh Kumar K.V
1ca7212932 powerpc/mm: Move PTE bits from generic functions to hash64 functions.
functions which operate on pte bits are moved to hash*.h and other
generic functions are moved to pgtable.h

Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 15:19:08 +11:00
Aneesh Kumar K.V
371352ca0e powerpc/mm: Move hash64 PTE bits from book3s/64/pgtable.h to hash.h
This enables us to keep hash64 related bits together, and makes it easy
to follow.

Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 15:19:08 +11:00
Aneesh Kumar K.V
f281b5d50c powerpc/mm: Don't use pmd_val, pud_val and pgd_val as lvalue
We convert them static inline function here as we did with pte_val in
the previous patch

Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 15:19:07 +11:00
Aneesh Kumar K.V
10bd3808df powerpc/mm: Don't use pte_val as lvalue
We also convert few #define to static inline in this patch for better
type checking

Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 15:19:07 +11:00
Aneesh Kumar K.V
b0412ea94b powerpc/mm: Drop pte-common.h from BOOK3S 64
We copy only needed PTE bits define from pte-common.h to respective
hash related header. This should greatly simply later patches in which
we are going to change the pte format for hash config

Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 15:19:06 +11:00
Aneesh Kumar K.V
ee4889c7bc powerpc/mm: Don't have generic headers introduce functions touching pte bits
We are going to drop pte_common.h in the later patch. The idea is to
enable hash code not require to define all PTE bits. Having PTE bits
defined in pte_common.h made the code unnecessarily complex.

Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 15:19:06 +11:00
Aneesh Kumar K.V
cbbb8683fb powerpc/mm: Delete booke bits from book3s
We also move __ASSEMBLY__ towards the end of header. This avoid
having #ifndef __ASSEMBLY___ all over the header

Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 15:19:05 +11:00
Aneesh Kumar K.V
ab537dca2f powerpc/mm: Move hash specific pte width and other defines to book3s
This further make a copy of pte defines to book3s/64/hash*.h. This
remove the dependency on pgtable-ppc64-4k.h and pgtable-ppc64-64k.h

Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 15:19:05 +11:00
Aneesh Kumar K.V
3dfcb315d8 powerpc/mm: make a separate copy for book3s
In this patch we do:
cp pgtable-ppc32.h book3s/32/pgtable.h
cp pgtable-ppc64.h book3s/64/pgtable.h

This enable us to do further changes to hash specific config.
We will change the page table format for 64bit hash in later patches.

Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 15:19:05 +11:00
Aneesh Kumar K.V
26b6a3d9bb powerpc/mm: move pte headers to book3s directory
Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-14 15:19:04 +11:00