x86-64 assumes NX is available by default, so we need to
explicitly check for it before using NX.  Some first-generation
Intel x86-64 processors didn't support NX, and even recent systems
allow it to be disabled in BIOS.

[ Impact: prevent Xen crash on NX-less 64-bit machines ]
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stable Kernel <stable@kernel.org>

Split __phys_addr out into its own file so we can disable
-fstack-protector in a fine-grained fashion.  Also it doesn't
have terribly much to do with the rest of ioremap.c.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

Needed by KVM.
Signed-off-by: NAvi Kivity <avi@redhat.com>

-fstack-protector uses a special per-cpu "stack canary" value.
gcc generates special code in each function to test the canary to make
sure that the function's stack hasn't been overrun.

On x86-64, this is simply an offset of %gs, which is the usual per-cpu
base segment register, so setting it up simply requires loading %gs's
base as normal.

On i386, the stack protector segment is %gs (rather than the usual kernel
percpu %fs segment register).  This requires setting up the full kernel
GDT and then loading %gs accordingly.  We also need to make sure %gs is
initialized when bringing up secondary cpus too.

To keep things consistent, we do the full GDT/segment register setup on
both architectures.

Because we need to avoid -fstack-protected code before setting up the GDT
and because there's no way to disable it on a per-function basis, several
files need to have stack-protector inhibited.

[ Impact: allow Xen booting with stack-protector enabled ]
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

Fix address passed to cpa_flush_range() when changing page
attributes from WB to UC. The address (*addr) is
modified by __change_page_attr_set_clr(). The result is that
the pages being flushed start at the _end_ of the changed range
instead of the beginning.

This should be considered for 2.6.30-stable and 2.6.31-stable.
Signed-off-by: NJack Steiner <steiner@sgi.com>
Acked-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Cc: Stable team <stable@kernel.org>

Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Some NUMA messages in srat_32.c are confusing to users,
because they seem to indicate errors, while in fact they
reflect normal behaviour.

Decrease the level of these messages to KERN_DEBUG so that
they don't show up unnecessarily.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
LKML-Reference: <200909050107.45175.rjw@sisk.pl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Ingo Molnar reported the following kmemcheck warning when running both
kmemleak and kmemcheck enabled:

  PM: Adding info for No Bus:vcsa7
  WARNING: kmemcheck: Caught 32-bit read from uninitialized memory
  (f6f6e1a4)
  d873f9f600000000c42ae4c1005c87f70000000070665f666978656400000000
   i i i i u u u u i i i i i i i i i i i i i i i i i i i i i u u u
           ^

  Pid: 3091, comm: kmemleak Not tainted (2.6.31-rc7-tip #1303) P4DC6
  EIP: 0060:[<c110301f>] EFLAGS: 00010006 CPU: 0
  EIP is at scan_block+0x3f/0xe0
  EAX: f40bd700 EBX: f40bd780 ECX: f16b46c0 EDX: 00000001
  ESI: f6f6e1a4 EDI: 00000000 EBP: f10f3f4c ESP: c2605fcc
   DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
  CR0: 8005003b CR2: e89a4844 CR3: 30ff1000 CR4: 000006f0
  DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
  DR6: ffff4ff0 DR7: 00000400
   [<c110313c>] scan_object+0x7c/0xf0
   [<c1103389>] kmemleak_scan+0x1d9/0x400
   [<c1103a3c>] kmemleak_scan_thread+0x4c/0xb0
   [<c10819d4>] kthread+0x74/0x80
   [<c10257db>] kernel_thread_helper+0x7/0x3c
   [<ffffffff>] 0xffffffff
  kmemleak: 515 new suspected memory leaks (see
  /sys/kernel/debug/kmemleak)
  kmemleak: 42 new suspected memory leaks (see /sys/kernel/debug/kmemleak)

The problem here is that kmemleak will scan partially initialized
objects that makes kmemcheck complain. Fix that up by skipping
uninitialized memory regions when kmemcheck is enabled.
Reported-by: NIngo Molnar <mingo@elte.hu>
Acked-by: NIngo Molnar <mingo@elte.hu>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>

Add sanity check for remap_pfn_range of RAM regions using
lookup_memtype(). Previously, we did not have anyway to get the type of
RAM memory regions as they were tracked using a single bit in
page_struct (WB, nonWB). Now we can get the actual type from page struct
(WB, WC, UC_MINUS) and make sure the requester gets that type.
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Lookup the reserved memtype during vm_insert_pfn and use that memtype
for the new mapping. This takes care or handling of vm_insert_pfn()
interface in track_pfn_vma*/untrack_pfn_vma.
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Add a new routine lookup_memtype() to get the current memtype based on
the PAT reserves and frees.
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Change reserve_ram_pages_type and free_ram_pages_type to use 2 page
flags to track UC_MINUS, WC, WB and default types. Previous RAM tracking
just tracked WB or NonWB, which was not complete and did not allow
tracking of RAM fully and there was no way to get the actual type
reserved by looking at the page flags.

We use the memtype_lock spinlock for atomicity in dealing with
memtype tracking in struct page.
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

PAT memtype tracking uses a linear link list to keep track of IO
(non-RAM) regions and their memtypes. The code used a last_accessed
pointer as a cache to speedup the lookup. As per discussions with
H. Peter Anvin a while back, having a rbtree here will avoid bad
performances in pathological cases where we may end up with huge
linked list. This may not add any noticable performance speedup
in normal case as the number of entires in PAT memtype list tend
to be ~20-30 range. The patch removes the "cached_entry" logic
as with rbtree we have more generic way of speeding up the lookup.

With this patch, we use rbtree to do the quick lookup. We still use
linked list as the memtype range tracked can be of different sizes
and can overlap in different ways. We also keep track of usage counts
with linked list.

Example:
Multiple ioremaps with different sizes
uncached-minus @ 0xfffff00000-0xfffff04000
uncached-minus @ 0xfffff02000-0xfffff03000

And one userlevel mmap and the thread forks a new process
uncached-minus @ 0xbf453000-0xbf454000
uncached-minus @ 0xbf453000-0xbf454000
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

io_mapping_* interfaces were added, mainly for graphics drivers.
Make this interface go through the PAT reserve/free, instead of
hardcoding WC mapping. This makes sure that there are no
aliases due to unconditional WC setting.
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Add new routines to request memtype for IO regions. This will currently
be a backend for io_mapping_* routines. But, it can also be made available
to drivers directly in future, in case it is needed.

reserve interface reserves the memory, makes sure we have a compatible
memory type available and keeps the identity map in sync when needed.
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

ioremap has this hard-coded check for new type and requested type. That
check differs from other PAT users like /dev/mem mmap, remap_pfn_range
in only one condition where requested type is UC_MINUS and new type
is WC. Under that condition, ioremap fails. But other PAT interfaces succeed
with a WC mapping.

Change to make ioremap be in sync with other PAT APIs and use the same
macro as others. Also changes the error print to KERN_ERR instead of
pr_debug.
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Make reserve_memtype internally take care of pat disabled case and fallback
to default return values.

Remove the specific pat_disabled checks in track_* routines.

Change kernel_map_sync_memtype to sync identity map even when
pat_disabled.

This change ensures that, even for pat_disabled case, we take care of
keeping identity map in sync. Before this patch, in pat disabled case,
ioremap() keeps the identity maps in sync and other APIs like pci and
/dev/mem mmap don't, which is not a very consistent behavior.
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

This line looks suspicious, because if this is true, then the
'flags' parameter of function reserve_bootmem_generic() will be
unused when !CONFIG_NUMA. I don't think this is what we want.
Signed-off-by: NWANG Cong <amwang@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: akpm@linux-foundation.org
LKML-Reference: <20090821083709.5098.52505.sendpatchset@localhost.localdomain>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

As noted in 83d349f3 ("x86: don't send
an IPI to the empty set of CPU's"), some APIC's will be very unhappy
with an empty destination mask.  That commit added a WARN_ON() for that
case, and avoided the resulting problem, but didn't fix the underlying
reason for why those empty mask cases happened.

This fixes that, by checking the result of 'cpumask_andnot()' of the
current CPU actually has any other CPU's left in the set of CPU's to be
sent a TLB flush, and not calling down to the IPI code if the mask is
empty.

The reason this started happening at all is that we started passing just
the CPU mask pointers around in commit 4595f962 ("x86: change
flush_tlb_others to take a const struct cpumask"), and when we did that,
the cpumask was no longer thread-local.

Before that commit, flush_tlb_mm() used to create it's own copy of
'mm->cpu_vm_mask' and pass that copy down to the low-level flush
routines after having tested that it was not empty.  But after changing
it to just pass down the CPU mask pointer, the lower level TLB flush
routines would now get a pointer to that 'mm->cpu_vm_mask', and that
could still change - and become empty - after the test due to other
CPU's having flushed their own TLB's.

See

	http://bugzilla.kernel.org/show_bug.cgi?id=13933

for details.
Tested-by: NThomas Björnell <thomas.bjornell@gmail.com>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This line looks suspicious, because if this is true, then the
'flags' parameter of function reserve_bootmem_generic() will be
unused when !CONFIG_NUMA. I don't think this is what we want.
Signed-off-by: NWANG Cong <amwang@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: akpm@linux-foundation.org
LKML-Reference: <20090821083709.5098.52505.sendpatchset@localhost.localdomain>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Max Vozeler reported:
>  Bug 13877 -  bogl-term broken with CONFIG_X86_PAT=y, works with =n
>
>  strace of bogl-term:
>  814   mmap2(NULL, 65536, PROT_READ|PROT_WRITE, MAP_SHARED, 4, 0)
>				 = -1 EAGAIN (Resource temporarily unavailable)
>  814   write(2, "bogl: mmaping /dev/fb0: Resource temporarily unavailable\n",
>	       57) = 57

PAT code maps the ISA memory range as WB in the PAT attribute, so that
fixed range MTRR registers define the actual memory type (UC/WC/WT etc).

But the upper level is_new_memtype_allowed() API checks are failing,
as the request here is for UC and the return tracked type is WB (Tracked type is
WB as MTRR type for this legacy range potentially will be different for each
4k page).

Fix is_new_memtype_allowed() by always succeeding the ISA address range
checks, as the null PAT (WB) and def MTRR fixed range register settings
satisfy the memory type needs of the applications that map the ISA address
range.
Reported-and-Tested-by: NMax Vozeler <xam@debian.org>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

With x86 converted to embedding allocator, lpage doesn't have any user
left.  Kill it along with cpa handling code.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Jan Beulich <JBeulich@novell.com>

With VMALLOC_END included in the calculation of MAXMEM (as of
2.6.28) it is no longer correct to also bump __VMALLOC_RESERVE
in reserve_top_address(). Doing so results in needlessly small
lowmem.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
LKML-Reference: <4A71DD2A020000780000D482@vpn.id2.novell.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The code was incorrectly reserving memtypes using the page
virtual address instead of the physical address. Furthermore,
the code was not ignoring highmem pages as it ought to.

( upstream does not pass in highmem pages yet - but upcoming
  graphics code will do it and there's no reason to not handle
  this properly in the CPA APIs.)

Fixes: http://bugzilla.kernel.org/show_bug.cgi?id=13884Signed-off-by: NThomas Hellstrom <thellstrom@vmware.com>
Acked-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: <stable@kernel.org>
Cc: dri-devel@lists.sourceforge.net
Cc: venkatesh.pallipadi@intel.com
LKML-Reference: <1249284345-7654-1-git-send-email-thellstrom@vmware.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Changeset 3869c4aa
that went in after 2.6.30-rc1 was a seemingly small change to _set_memory_wc()
to make it complaint with SDM requirements. But, introduced a nasty bug, which
can result in crash and/or strange corruptions when set_memory_wc is used.
One such crash reported here
http://lkml.org/lkml/2009/7/30/94

Actually, that changeset introduced two bugs.
* change_page_attr_set() takes &addr as first argument and can the addr value
  might have changed on return, even for single page change_page_attr_set()
  call. That will make the second change_page_attr_set() in this routine
  operate on unrelated addr, that can eventually cause strange corruptions
  and bad page state crash.
* The second change_page_attr_set() call, before setting _PAGE_CACHE_WC, should
  clear the earlier _PAGE_CACHE_UC_MINUS, as otherwise cache attribute will not
  be WC (will be UC instead).

The patch below fixes both these problems. Sending a single patch to fix both
the problems, as the change is to the same line of code. The change to have a
addr_copy is not very clean. But, it is simpler than making more changes
through various routines in pageattr.c.

A huge thanks to Jerome for reporting this problem and providing a simple test
case that helped us root cause the problem.
Reported-by: NJerome Glisse <glisse@freedesktop.org>
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20090730214319.GA1889@linux-os.sc.intel.com>
Acked-by: NDave Airlie <airlied@redhat.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

This functionality is needed to kmap_atomic() highmem pages that may
potentially have or are about to set up other mappings with
non-standard caching attributes.
Signed-off-by: NThomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

mm: Pass virtual address to [__]p{te,ud,md}_free_tlb()

Upcoming paches to support the new 64-bit "BookE" powerpc architecture
will need to have the virtual address corresponding to PTE page when
freeing it, due to the way the HW table walker works.

Basically, the TLB can be loaded with "large" pages that cover the whole
virtual space (well, sort-of, half of it actually) represented by a PTE
page, and which contain an "indirect" bit indicating that this TLB entry
RPN points to an array of PTEs from which the TLB can then create direct
entries. Thus, in order to invalidate those when PTE pages are deleted,
we need the virtual address to pass to tlbilx or tlbivax instructions.

The old trick of sticking it somewhere in the PTE page struct page sucks
too much, the address is almost readily available in all call sites and
almost everybody implemets these as macros, so we may as well add the
argument everywhere. I added it to the pmd and pud variants for consistency.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: David Howells <dhowells@redhat.com> [MN10300 & FRV]
Acked-by: NNick Piggin <npiggin@suse.de>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> [s390]
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Need to clear both nodes and nodes_add state for start/end.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
LKML-Reference: <20090718065657.GA2898@basil.fritz.box>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Cc: stable@kernel.org

Since commit 5fd29d6c ("printk: clean up handling of log-levels
and newlines"), the kernel logs segfaults like:

    <6>gnome-power-man[24509]: segfault at 20 ip 00007f9d4950465a sp 00007fffbb50fc70 error 4 in libgobject-2.0.so.0.2103.0[7f9d494f7000+45000]

with the extra "<6>" being KERN_INFO.  This happens because the
printk in show_signal_msg() started with KERN_CONT and then
used "%s" to pass in the real level; and KERN_CONT is no longer
an empty string, and printk only pays attention to the level at
the very beginning of the format string.

Therefore, remove the KERN_CONT from this printk, since it is
now actively causing problems (and never really made any
sense).
Signed-off-by: NRoland Dreier <roland@digitalvampire.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <874otjitkj.fsf@shaolin.home.digitalvampire.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Alex found that specjbb2005 still can not run with hugepages on an
x86-64 machine.  This only happens when numa is not compiled in.

The root cause: node_set_state will not set it back for us in that case,
so don't clear that when numa is not select in config

[ v2: use node_clear_state instead ]
Reported-and-Tested-by: NAlex Shi <alex.shi@intel.com>
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Reviewed-by: NChristoph Lameter <cl@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 5fd29d6c ("printk: clean up
handling of log-levels and newlines") changed printk semantics.  printk
lines with multiple KERN_<level> prefixes are no longer emitted as
before the patch.

<level> is now included in the output on each additional use.

Remove all uses of multiple KERN_<level>s in formats.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Generalize and move x86 setup_pcpu_lpage() into
pcpu_lpage_first_chunk().  setup_pcpu_lpage() now is a simple wrapper
around the generalized version.  Other than taking size parameters and
using arch supplied callbacks to allocate/free/map memory,
pcpu_lpage_first_chunk() is identical to the original implementation.

This simplifies arch code and will help converting more archs to
dynamic percpu allocator.

While at it, factor out pcpu_calc_fc_sizes() which is common to
pcpu_embed_first_chunk() and pcpu_lpage_first_chunk().

[ Impact: code reorganization and generalization ]
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>

This sparse warning:

  arch/x86/mm/init.c:83:16: warning: symbol 'check_efer' was not declared. Should it be static?

triggers because check_efer() is not decalared before using it.
asm/proto.h includes the declaration of check_efer(), so
including asm/proto.h to fix that - this also addresses the
sparse warning.
Signed-off-by: NJaswinder Singh Rajput <jaswinderrajput@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <1246458263.6940.22.camel@hpdv5.satnam>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Nathan reported that

| commit 73d60b7f
| Author: Yinghai Lu <yinghai@kernel.org>
| Date:   Tue Jun 16 15:33:00 2009 -0700
|
|    page-allocator: clear N_HIGH_MEMORY map before we set it again
|
|    SRAT tables may contains nodes of very small size.  The arch code may
|    decide to not activate such a node.  However, currently the early boot
|    code sets N_HIGH_MEMORY for such nodes.  These nodes therefore seem to be
|    active although these nodes have no present pages.
|
|    For 64bit N_HIGH_MEMORY == N_NORMAL_MEMORY, so that works for 64 bit too

unintentionally and incorrectly clears the cpuset.mems cgroup attribute on
an i386 kvm guest, meaning that cpuset.mems can not be used.

Fix this by only clearing node_states[N_NORMAL_MEMORY] for 64bit only.
and need to do save/restore for that in find_zone_movable_pfn
Reported-by: NNathan Lynch <ntl@pobox.com>
Tested-by: NNathan Lynch <ntl@pobox.com>
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>,
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NFigo.zhang <figo1802@gmail.com>
Cc: Andrew Morton <akpm@osdl.org>
LKML-Reference: <1246248175.5759.12.camel@myhost>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Use pgtable access helpers for 32-bit version dump_pagetable()
and get rid of __typeof__() operators. This needs to make
pmd_pfn() available for 2-level pgtable.

Also, remove some casts for 64-bit version dump_pagetable().
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
LKML-Reference: <20090627063514.GA2834@localhost.localdomain>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The init_gbpages() function is conditionally called from
init_memory_mapping() function. There are two call-sites where
this 'after_bootmem' condition can be true: setup_arch() and
mem_init() via pci_iommu_alloc().

Therefore, it's safe to move the call to init_gbpages() to
setup_arch() as it's always called before mem_init().

This removes an after_bootmem use - paving the way to remove
all uses of that state variable.
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
Acked-by: NYinghai Lu <yinghai@kernel.org>
LKML-Reference: <Pine.LNX.4.64.0906221731210.19474@melkki.cs.Helsinki.FI>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

lpage allocator aliases a PMD page for each cpu and returns whatever
is unused to the page allocator.  When the pageattr of the recycled
pages are changed, this makes the two aliases point to the overlapping
regions with different attributes which isn't allowed and known to
cause subtle data corruption in certain cases.

This can be handled in simliar manner to the x86_64 highmap alias.
pageattr code should detect if the target pages have PMD alias and
split the PMD alias and synchronize the attributes.

pcpur allocator is updated to keep the allocated PMD pages map sorted
in ascending address order and provide pcpu_lpage_remapped() function
which binary searches the array to determine whether the given address
is aliased and if so to which address.  pageattr is updated to use
pcpu_lpage_remapped() to detect the PMD alias and split it up as
necessary from cpa_process_alias().

Jan Beulich spotted the original problem and incorrect usage of vaddr
instead of laddr for lookup.

With this, lpage percpu allocator should work correctly.  Re-enable
it.

[ Impact: fix subtle lpage pageattr bug and re-enable lpage ]
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NJan Beulich <JBeulich@novell.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>

Reorganize cpa_process_alias() so that new alias condition can be
added easily.

Jan Beulich spotted problem in the original cleanup thread which
incorrectly assumed the two existing conditions were mutially
exclusive.

[ Impact: code reorganization ]
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>

This allows the callers to now pass down the full set of FAULT_FLAG_xyz
flags to handle_mm_fault().  All callers have been (mechanically)
converted to the new calling convention, there's almost certainly room
for architectures to clean up their code and then add FAULT_FLAG_RETRY
when that support is added.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>