Assign Write-Through type to the PA7 slot in the PAT MSR when
the processor is not affected by PAT errata. The PA7 slot is
chosen to improve robustness in the presence of errata that
might cause the high PAT bit to be ignored. This way a buggy PA7
slot access will hit the PA3 slot, which is UC, so at worst we
lose performance without causing a correctness issue.

The following Intel processors are affected by the PAT errata.

  Errata               CPUID
  ----------------------------------------------------
  Pentium 2, A52       family 0x6, model 0x5
  Pentium 3, E27       family 0x6, model 0x7, 0x8
  Pentium 3 Xenon, G26 family 0x6, model 0x7, 0x8, 0xa
  Pentium M, Y26       family 0x6, model 0x9
  Pentium M 90nm, X9   family 0x6, model 0xd
  Pentium 4, N46       family 0xf, model 0x0

Instead of making sharp boundary checks, we remain conservative
and exclude all Pentium 2, 3, M and 4 family processors. For
those, _PAGE_CACHE_MODE_WT is redirected to UC- per the default
setup in __cachemode2pte_tbl[].
Signed-off-by: NToshi Kani <toshi.kani@hp.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Elliott@hp.com
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arnd@arndb.de
Cc: hch@lst.de
Cc: hmh@hmh.eng.br
Cc: jgross@suse.com
Cc: konrad.wilk@oracle.com
Cc: linux-mm <linux-mm@kvack.org>
Cc: linux-nvdimm@lists.01.org
Cc: stefan.bader@canonical.com
Cc: yigal@plexistor.com
Link: https://lkml.kernel.org/r/1433187393-22688-2-git-send-email-toshi.kani@hp.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Now that we emulate a PAT table when PAT is disabled, there's no
need for those checks anymore as the PAT abstraction will handle
those cases too.

Based on a conglomerate patch from Toshi Kani.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Reviewed-by: NToshi Kani <toshi.kani@hp.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Elliott@hp.com
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arnd@arndb.de
Cc: hch@lst.de
Cc: hmh@hmh.eng.br
Cc: jgross@suse.com
Cc: konrad.wilk@oracle.com
Cc: linux-mm <linux-mm@kvack.org>
Cc: linux-nvdimm@lists.01.org
Cc: stefan.bader@canonical.com
Cc: yigal@plexistor.com
Link: http://lkml.kernel.org/r/1433436928-31903-4-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

In the case when PAT is disabled on the command line with
"nopat" or when virtualization doesn't support PAT (correctly) -
see

  9d34cfdf ("x86: Don't rely on VMWare emulating PAT MSR correctly").

we emulate it using the PWT and PCD cache attribute bits. Get
rid of boot_pat_state while at it.

Based on a conglomerate patch from Toshi Kani.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Reviewed-by: NToshi Kani <toshi.kani@hp.com>
Acked-by: NJuergen Gross <jgross@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Elliott@hp.com
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arnd@arndb.de
Cc: hch@lst.de
Cc: hmh@hmh.eng.br
Cc: konrad.wilk@oracle.com
Cc: linux-mm <linux-mm@kvack.org>
Cc: linux-nvdimm@lists.01.org
Cc: stefan.bader@canonical.com
Cc: yigal@plexistor.com
Link: http://lkml.kernel.org/r/1433436928-31903-3-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

Split it into a BSP and AP version which makes the PAT
initialization path actually readable again.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Reviewed-by: NToshi Kani <toshi.kani@hp.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Elliott@hp.com
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arnd@arndb.de
Cc: hch@lst.de
Cc: hmh@hmh.eng.br
Cc: jgross@suse.com
Cc: konrad.wilk@oracle.com
Cc: linux-mm <linux-mm@kvack.org>
Cc: linux-nvdimm@lists.01.org
Cc: stefan.bader@canonical.com
Cc: yigal@plexistor.com
Link: http://lkml.kernel.org/r/1433436928-31903-2-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

Two Linux device drivers cannot work with PAT and the work
required to make them work is significant. There is not enough
motivation to convert these drivers over to use PAT properly,
the compromise reached is to let drivers that cannot be ported
to PAT check if PAT was enabled and if so fail on probe with a
recommendation to boot with the "nopat" kernel parameter.
Signed-off-by: NLuis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Walls <awalls@md.metrocast.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1430425520-22275-4-git-send-email-mcgrof@do-not-panic.com
Link: http://lkml.kernel.org/r/1432628901-18044-14-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

We use pat_enabled in x86-specific code to see if PAT is enabled
or not but we're granting full access to it even though readers
do not need to set it. If, for instance, we granted access to it
to modules later they then could override the variable
setting... no bueno.

This renames pat_enabled to a new static variable __pat_enabled.
Folks are redirected to use pat_enabled() now.

Code that sets this can only be internal to pat.c. Apart from
the early kernel parameter "nopat" to disable PAT, we also have
a few cases that disable it later and make use of a helper
pat_disable(). It is wrapped under an ifdef but since that code
cannot run unless PAT was enabled its not required to wrap it
with ifdefs, unwrap that. Likewise, since "nopat" doesn't really
change non-PAT systems just remove that ifdef as well.

Although we could add and use an early_param_off(), these
helpers don't use __read_mostly but we want to keep
__read_mostly for __pat_enabled as this is a hot path -- upon
boot, for instance, a simple guest may see ~4k accesses to
pat_enabled(). Since __read_mostly early boot params are not
that common we don't add a helper for them just yet.
Signed-off-by: NLuis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Walls <awalls@md.metrocast.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kyle McMartin <kyle@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1430425520-22275-3-git-send-email-mcgrof@do-not-panic.com
Link: http://lkml.kernel.org/r/1432628901-18044-13-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

Use pr_info() instead of the old printk to prefix the component
where things are coming from. With this readers will know
exactly where the message is coming from. We use pr_* helpers
but define pr_fmt to the empty string for easier grepping for
those error messages.

We leave the users of dprintk() in place, this will print only
when the debugpat kernel parameter is enabled. We want to leave
those enabled as a debug feature, but also make them use the
same prefix.
Signed-off-by: NLuis R. Rodriguez <mcgrof@suse.com>
[ Kill pr_fmt. ]
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Walls <awalls@md.metrocast.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: cocci@systeme.lip6.fr
Cc: plagnioj@jcrosoft.com
Cc: tomi.valkeinen@ti.com
Link: http://lkml.kernel.org/r/1430425520-22275-2-git-send-email-mcgrof@do-not-panic.com
Link: http://lkml.kernel.org/r/1432628901-18044-9-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

This patch adds the argument 'uniform' to mtrr_type_lookup(),
which gets set to 1 when a given range is covered uniformly by
MTRRs, i.e. the range is fully covered by a single MTRR entry or
the default type.

Change pud_set_huge() and pmd_set_huge() to honor the 'uniform'
flag to see if it is safe to create a huge page mapping in the
range.

This allows them to create a huge page mapping in a range
covered by a single MTRR entry of any memory type. It also
detects a non-optimal request properly. They continue to check
with the WB type since it does not effectively change the
uniform mapping even if a request spans multiple MTRR entries.

pmd_set_huge() logs a warning message to a non-optimal request
so that driver writers will be aware of such a case. Drivers
should make a mapping request aligned to a single MTRR entry
when the range is covered by MTRRs.
Signed-off-by: NToshi Kani <toshi.kani@hp.com>
[ Realign, flesh out comments, improve warning message. ]
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Elliott@hp.com
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave.hansen@intel.com
Cc: linux-mm <linux-mm@kvack.org>
Cc: pebolle@tiscali.nl
Link: http://lkml.kernel.org/r/1431714237-880-7-git-send-email-toshi.kani@hp.com
Link: http://lkml.kernel.org/r/1432628901-18044-8-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

STRICT_DEVMEM and PAT produce same failure accessing /dev/mem,
which is quite confusing to the user. Make printk messages
different to lessen confusion.
Signed-off-by: NPavel Machek <pavel@ucw.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

VMWare seems not to emulate the PAT MSR correctly: reaeding
MSR_IA32_CR_PAT returns 0 even after writing another value to it.

Commit bd809af1 triggers this VMWare bug when the kernel is
booted as a VMWare guest.

Detect this bug and don't use the read value if it is 0.

Fixes: bd809af1 "x86: Enable PAT to use cache mode translation tables"
Reported-and-tested-by: NJongman Heo <jongman.heo@samsung.com>
Acked-by: NAlok N Kataria <akataria@vmware.com>
Signed-off-by: NJuergen Gross <jgross@suse.com>
Link: http://lkml.kernel.org/r/1421039745-14335-1-git-send-email-jgross@suse.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

seq_puts is a lot cheaper than seq_printf, so use that to print
literal strings.
Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Link: http://lkml.kernel.org/r/1417208622-12264-1-git-send-email-linux@rasmusvillemoes.dkSigned-off-by: NIngo Molnar <mingo@kernel.org>

Commit e00c8cc9 "x86: Use new cache mode type in memtype related
functions" broke the ARCH=um build.

 arch/x86/include/asm/cacheflush.h:67:36: error: return type is an incomplete type
 static inline enum page_cache_mode get_page_memtype(struct page *pg)

The reason is simple. get_page_memtype() and set_page_memtype()
require enum page_cache_mode now, which is defined in
asm/pgtable_types.h. UM does not include that file for obvious reasons.

The simple solution is to move that functions to arch/x86/mm/pat.c
where the only callsites of this are located. They should have been
there in the first place.

Fixes: e00c8cc9 "x86: Use new cache mode type in memtype related functions"
Reported-by: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Juergen Gross <jgross@suse.com>
Cc: Richard Weinberger <richard@nod.at>

Update the translation tables from cache mode to pgprot values
according to the PAT settings. This enables changing the cache
attributes of a PAT index in just one place without having to change
at the users side.

With this change it is possible to use the same kernel with different
PAT configurations, e.g. supporting Xen.
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NToshi Kani <toshi.kani@hp.com>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Cc: stefan.bader@canonical.com
Cc: xen-devel@lists.xensource.com
Cc: ville.syrjala@linux.intel.com
Cc: david.vrabel@citrix.com
Cc: jbeulich@suse.com
Cc: plagnioj@jcrosoft.com
Cc: tomi.valkeinen@ti.com
Cc: bhelgaas@google.com
Link: http://lkml.kernel.org/r/1415019724-4317-18-git-send-email-jgross@suse.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Instead of directly using the cache mode bits in the pte switch to
using the cache mode type.
Based-on-patch-by: NStefan Bader <stefan.bader@canonical.com>
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Cc: stefan.bader@canonical.com
Cc: xen-devel@lists.xensource.com
Cc: konrad.wilk@oracle.com
Cc: ville.syrjala@linux.intel.com
Cc: david.vrabel@citrix.com
Cc: jbeulich@suse.com
Cc: toshi.kani@hp.com
Cc: plagnioj@jcrosoft.com
Cc: tomi.valkeinen@ti.com
Cc: bhelgaas@google.com
Link: http://lkml.kernel.org/r/1415019724-4317-14-git-send-email-jgross@suse.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Instead of directly using the cache mode bits in the pte switch to
using the cache mode type.
Based-on-patch-by: NStefan Bader <stefan.bader@canonical.com>
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Cc: stefan.bader@canonical.com
Cc: xen-devel@lists.xensource.com
Cc: konrad.wilk@oracle.com
Cc: ville.syrjala@linux.intel.com
Cc: david.vrabel@citrix.com
Cc: jbeulich@suse.com
Cc: toshi.kani@hp.com
Cc: plagnioj@jcrosoft.com
Cc: tomi.valkeinen@ti.com
Cc: bhelgaas@google.com
Link: http://lkml.kernel.org/r/1415019724-4317-13-git-send-email-jgross@suse.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Instead of directly using the cache mode bits in the pte switch to
using the cache mode type. As those are the main callers of
lookup_memtype(), change this as well.
Based-on-patch-by: NStefan Bader <stefan.bader@canonical.com>
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Cc: stefan.bader@canonical.com
Cc: xen-devel@lists.xensource.com
Cc: konrad.wilk@oracle.com
Cc: ville.syrjala@linux.intel.com
Cc: david.vrabel@citrix.com
Cc: jbeulich@suse.com
Cc: toshi.kani@hp.com
Cc: plagnioj@jcrosoft.com
Cc: tomi.valkeinen@ti.com
Cc: bhelgaas@google.com
Link: http://lkml.kernel.org/r/1415019724-4317-10-git-send-email-jgross@suse.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Instead of directly using the cache mode bits in the pte switch to
using the cache mode type. This requires to change
io_reserve_memtype() as well.
Based-on-patch-by: NStefan Bader <stefan.bader@canonical.com>
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Cc: stefan.bader@canonical.com
Cc: xen-devel@lists.xensource.com
Cc: konrad.wilk@oracle.com
Cc: ville.syrjala@linux.intel.com
Cc: david.vrabel@citrix.com
Cc: jbeulich@suse.com
Cc: toshi.kani@hp.com
Cc: plagnioj@jcrosoft.com
Cc: tomi.valkeinen@ti.com
Cc: bhelgaas@google.com
Link: http://lkml.kernel.org/r/1415019724-4317-9-git-send-email-jgross@suse.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Instead of directly using the cache mode bits in the pte switch to
using the cache mode type. This requires changing some callers of
is_new_memtype_allowed() to be changed as well.
Based-on-patch-by: NStefan Bader <stefan.bader@canonical.com>
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Cc: stefan.bader@canonical.com
Cc: xen-devel@lists.xensource.com
Cc: konrad.wilk@oracle.com
Cc: ville.syrjala@linux.intel.com
Cc: david.vrabel@citrix.com
Cc: jbeulich@suse.com
Cc: toshi.kani@hp.com
Cc: plagnioj@jcrosoft.com
Cc: tomi.valkeinen@ti.com
Cc: bhelgaas@google.com
Link: http://lkml.kernel.org/r/1415019724-4317-8-git-send-email-jgross@suse.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

kernel_map_sync_memtype() is called from a variety of contexts.  The
pat.c code that calls it seems to ensure that it is not called for
non-ram areas by checking via pat_pagerange_is_ram().  It is important
that it only be called on the actual identity map because there *IS*
no map to sync for highmem pages, or for memory holes.

The ioremap.c uses are not as careful as those from pat.c, and call
kernel_map_sync_memtype() on PCI space which is in the middle of the
kernel identity map _range_, but is not actually mapped.

This patch adds a check to kernel_map_sync_memtype() which probably
duplicates some of the checks already in pat.c.  But, it is necessary
for the ioremap.c uses and shouldn't hurt other callers.

I have reproduced this bug and this patch fixes it for me and the
original bug reporter:

	https://lkml.org/lkml/2013/2/5/396Signed-off-by: NDave Hansen <dave@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20130307163151.D9B58C4E@kernel.stglabs.ibm.comSigned-off-by: NDave Hansen <dave@sr71.net>
Tested-by: NTetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

The KVM code has some repeated bugs in it around use of __pa() on
per-cpu data.  Those data are not in an area on which using
__pa() is valid.  However, they are also called early enough in
boot that __vmalloc_start_set is not set, and thus the
CONFIG_DEBUG_VIRTUAL debugging does not catch them.

This adds a check to also verify __pa() calls against max_low_pfn,
which we can use earler in boot than is_vmalloc_addr().  However,
if we are super-early in boot, max_low_pfn=0 and this will trip
on every call, so also make sure that max_low_pfn is set before
we try to use it.

With this patch applied, CONFIG_DEBUG_VIRTUAL will actually
catch the bug I was chasing (and fix later in this series).

I'd love to find a generic way so that any __pa() call on percpu
areas could do a BUG_ON(), but there don't appear to be any nice
and easy ways to check if an address is a percpu one.  Anybody
have ideas on a way to do this?
Signed-off-by: NDave Hansen <dave@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20130122212430.F46F8159@kernel.stglabs.ibm.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Replace the generic vma-flag VM_PFN_AT_MMAP with x86-only VM_PAT.

We can toss mapping address from remap_pfn_range() into
track_pfn_vma_new(), and collect all PAT-related logic together in
arch/x86/.

This patch also restores orignal frustration-free is_cow_mapping() check
in remap_pfn_range(), as it was before commit v2.6.28-rc8-88-g3c8bb73a
("x86: PAT: store vm_pgoff for all linear_over_vma_region mappings - v3")

is_linear_pfn_mapping() checks can be removed from mm/huge_memory.c,
because it already handled by VM_PFNMAP in VM_NO_THP bit-mask.

[suresh.b.siddha@intel.com: Reset the VM_PAT flag as part of untrack_pfn_vma()]
Signed-off-by: NKonstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: Venkatesh Pallipadi <venki@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Venkatesh Pallipadi <venki@google.com>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With PAT enabled, vm_insert_pfn() looks up the existing pfn memory
attribute and uses it.  Expectation is that the driver reserves the
memory attributes for the pfn before calling vm_insert_pfn().

remap_pfn_range() (when called for the whole vma) will setup a new
attribute (based on the prot argument) for the specified pfn range.
This addresses the legacy usage which typically calls remap_pfn_range()
with a desired memory attribute.  For ranges smaller than the vma size
(which is typically not the case), remap_pfn_range() will use the
existing memory attribute for the pfn range.

Expose two different API's for these different behaviors.
track_pfn_insert() for tracking the pfn attribute set by vm_insert_pfn()
and track_pfn_remap() for the remap_pfn_range().

This cleanup also prepares the ground for the track/untrack pfn vma
routines to take over the ownership of setting PAT specific vm_flag in
the 'vma'.

[khlebnikov@openvz.org: Clear checks in track_pfn_remap()]
[akpm@linux-foundation.org: tweak a few comments]
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NKonstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Venkatesh Pallipadi <venki@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

'pfn' argument for track_pfn_vma_new() can be used for reserving the
attribute for the pfn range.  No need to depend on 'vm_pgoff'

Similarly, untrack_pfn_vma() can depend on the 'pfn' argument if it is
non-zero or can use follow_phys() to get the starting value of the pfn
range.

Also the non zero 'size' argument can be used instead of recomputing it
from vma.

This cleanup also prepares the ground for the track/untrack pfn vma
routines to take over the ownership of setting PAT specific vm_flag in the
'vma'.

[khlebnikov@openvz.org: Clear pfn to paddr conversion]
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NKonstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Venkatesh Pallipadi <venki@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Function pat_pagerange_is_ram() scales poorly to large address
ranges, because it probes the resource tree for each page.

On a 2.6 GHz Opteron, this function consumes 34 ms for a 1 GB range.

It is called twice during untrack_pfn_vma(), slowing process
cleanup and handicapping the OOM killer.

This replacement consumes less than 1ms, under the same conditions.

Signed-off-by: John Dykstra <jdykstra@cray.com> on behalf of Cray Inc.
Acked-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1337980366.1979.6.camel@redwood
[ Small stylistic cleanups and renames ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Print physical address info in a style consistent with the %pR style used
elsewhere in the kernel.  For example:

    -found SMP MP-table at [ffff8800000fce90] fce90
    +found SMP MP-table at [mem 0x000fce90-0x000fce9f] mapped at [ffff8800000fce90]
    -initial memory mapped : 0 - 20000000
    +initial memory mapped: [mem 0x00000000-0x1fffffff]
    -Base memory trampoline at [ffff88000009c000] 9c000 size 8192
    +Base memory trampoline [mem 0x0009c000-0x0009dfff] mapped at [ffff88000009c000]
    -SRAT: Node 0 PXM 0 0-80000000
    +SRAT: Node 0 PXM 0 [mem 0x00000000-0x7fffffff]
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The following two commits fixed a problem that x86 ioremap() doesn't handle
physical address higher than 32-bit properly in X86_32 PAE mode.

 ffa71f33 (x86, ioremap: Fix incorrect
 physical address handling in PAE mode)

 35be1b71 (x86, ioremap: Fix normal
 ram range check)

But these fixes are not enough, since pat_pagerange_is_ram() in PAT code
also has a same problem. This patch fixes it.
Signed-off-by: NYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Reviewed-by: NKenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
LKML-Reference: <4C47DDCF.80300@jp.fujitsu.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

subtree_max_end that was recently added to struct memtype was not getting
properly initialized resulting in

WARNING: kmemcheck: Caught 64-bit read from uninitialized memory
in memtype_rb_augment_cb()
reported here
https://bugzilla.kernel.org/show_bug.cgi?id=16092

This change fixes the problem.
Reported-by: NChristian Casteyde <casteyde.christian@free.fr>
Tested-by: NChristian Casteyde <casteyde.christian@free.fr>
Signed-off-by: NVenkatesh Pallipadi <venki@google.com>
LKML-Reference: <1276217101-11515-1-git-send-email-venki@google.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>

Reserve_memtype will allocate memory for new memtype, but
in free_memtype, after the memtype erased from rbtree, the
memory is not freed.

Changes since V1:
	make rbt_memtype_erase return erased memtype so that
	it can be freed in free_memtype.

[ hpa: not for -stable: 2.6.34 and earlier not affected ]
Signed-off-by: NXiaotian Feng <dfeng@redhat.com>
LKML-Reference: <1274838670-8731-1-git-send-email-dfeng@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Jack Steiner <steiner@sgi.com>
Acked-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

While testing an application using the xpmem (out of kernel) driver, we
noticed a significant page fault rate reduction of x86_64 with respect
to ia64.  For one test running with 32 cpus, one thread per cpu, it
took 01:08 for each of the threads to vm_insert_pfn 2GB worth of pages.
For the same test running on 256 cpus, one thread per cpu, it took 14:48
to vm_insert_pfn 2 GB worth of pages.

The slowdown was tracked to lookup_memtype which acquires the
spinlock memtype_lock.  This heavily contended lock was slowing down
vm_insert_pfn().

With the cmpxchg on page->flags method, both the 32 cpu and 256 cpu
cases take approx 00:01.3 seconds to complete.
Signed-off-by: NRobin Holt <holt@sgi.com>
LKML-Reference: <20100423153627.751194346@gulag1.americas.sgi.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@gmail.com>
Cc: Rafael Wysocki <rjw@novell.com>
Reviewed-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

Move pat backend to fully rbtree based implementation from the existing
rbtree and linked list hybrid.

New rbtree based solution uses interval trees (augmented rbtrees) in
order to store the PAT ranges. The new code seprates out the pat backend
to pat_rbtree.c file, making is cleaner. The change also makes the PAT
lookup, reserve and free operations more optimal, as we don't have to
traverse linear linked list of few tens of entries in normal case.
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
LKML-Reference: <20100210232607.GB11465@linux-os.sc.intel.com>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Minor changes in pat.c to cleanup code and make it smoother to introduce
bigger rbtree only change in the following patch. The changes are cleaup
only and should not have any functional impact.
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
LKML-Reference: <20100210195909.792781000@intel.com>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

While Linux provided an O_SYNC flag basically since day 1, it took until
Linux 2.4.0-test12pre2 to actually get it implemented for filesystems,
since that day we had generic_osync_around with only minor changes and the
great "For now, when the user asks for O_SYNC, we'll actually give
O_DSYNC" comment.  This patch intends to actually give us real O_SYNC
semantics in addition to the O_DSYNC semantics.  After Jan's O_SYNC
patches which are required before this patch it's actually surprisingly
simple, we just need to figure out when to set the datasync flag to
vfs_fsync_range and when not.

This patch renames the existing O_SYNC flag to O_DSYNC while keeping it's
numerical value to keep binary compatibility, and adds a new real O_SYNC
flag.  To guarantee backwards compatiblity it is defined as expanding to
both the O_DSYNC and the new additional binary flag (__O_SYNC) to make
sure we are backwards-compatible when compiled against the new headers.

This also means that all places that don't care about the differences can
just check O_DSYNC and get the right behaviour for O_SYNC, too - only
places that actuall care need to check __O_SYNC in addition.  Drivers and
network filesystems have been updated in a fail safe way to always do the
full sync magic if O_DSYNC is set.  The few places setting O_SYNC for
lower layers are kept that way for now to stay failsafe.

We enforce that O_DSYNC is set when __O_SYNC is set early in the open path
to make sure we always get these sane options.

Note that parisc really screwed up their headers as they already define a
O_DSYNC that has always been a no-op.  We try to repair it by using it for
the new O_DSYNC and redefinining O_SYNC to send both the traditional
O_SYNC numerical value _and_ the O_DSYNC one.

Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Grant Grundler <grundler@parisc-linux.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Dilger <adilger@sun.com>
Acked-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: NKyle McMartin <kyle@mcmartin.ca>
Acked-by: NUlrich Drepper <drepper@redhat.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJan Kara <jack@suse.cz>

If pat is disabled (boot with nopat), there's no need to create
debugfs for it, it's empty all the time.
Signed-off-by: NXiaotian Feng <dfeng@redhat.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
LKML-Reference: <1259236428-16329-1-git-send-email-dfeng@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

- Change is_untracked_pat_range() to return bool.
- Clean up the initialization of is_untracked_pat_range() -- by default,
  we simply point it at is_ISA_range() directly.
- Move is_untracked_pat_range to the end of struct x86_platform, since
  it is the newest field.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Jack Steiner <steiner@sgi.com>
LKML-Reference: <20091119202341.GA4420@sgi.com>

is_untracked_pat_range() -- like its components, is_ISA_range() and
is_GRU_range(), takes a normal semiclosed interval (>=, <) whereas the
PAT code called it as if it took a closed range (>=, <=).  Fix.

Although this is a bug, I believe it is non-manifest, simply because
none of the callers will call this with non-page-aligned addresses.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NSuresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20091119202341.GA4420@sgi.com>

GRU space is always mapped as WB in the page table. There is
no need to track the mappings in the PAT. This also eliminates
the "freeing invalid memtype" messages when the GRU space is
unmapped.
Signed-off-by: NJack Steiner <steiner@sgi.com>
LKML-Reference: <20091119202341.GA4420@sgi.com>
[ v2: fix build failure ]
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Commit:

  b6ff32d9: x86, PAT: Consolidate code in pat_x_mtrr_type() and reserve_memtype()

consolidated code in pat_x_mtrr_type() and reserve_memtype(),
which removed the special case (req_type is -1) for the
PAT-enabled part.

We should also change comments and the PAT-disabled part.
Signed-off-by: NXiaotian Feng <dfeng@redhat.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
LKML-Reference: <1257844987-7906-1-git-send-email-dfeng@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

On modern systems, the kernel prints the message

    x86 PAT enabled: cpu 0, old 0x7040600070406, new 0x7010600070106

once for every CPU.

This gets kind of ridiculous on huge systems; for example, on a
64-thread system I was lucky enough to get:

    dmesg| grep 'PAT enabled' | wc
         64     704    5174

There is already a BUG() if non-boot CPUs have PAT capabilities
that don't match the boot CPU, so just print the message on the
boot CPU. (I kept the print after the wrmsrl() that enables PAT,
so that the log output continues to mean that the system survived
enabling PAT on the boot CPU)
Signed-off-by: NRoland Dreier <rolandd@cisco.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
LKML-Reference: <adavdj92sso.fsf@cisco.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Recent enhancement of rb-tree based lookup exposed a  bug with the lookup
mechanism in the reserve_memtype() which ensures that there are no conflicting
memtype requests for the memory range.

memtype_rb_search() returns an entry which has a start address <= new start
address. And from here we traverse the linear linked list to check if there
any conflicts with the existing mappings. As the rbtree is based on the
start address of the memory range, it is quite possible that we have several
overlapped mappings whose start address is much less than new requested start
but the end is >= new requested end. This results in conflicting memtype
mappings.

Same bug exists with the old code which uses cached_entry from where
we traverse the linear linked list. But the new rb-tree code exposes this
bug fairly easily.

For now, don't use the memtype_rb_search() and always start the search from
the head of linear linked list in reserve_memtype(). Linear linked list
for most of the systems grow's to few 10's of entries(as we track memory type
of RAM pages using struct page). So we should be ok for now.

We still retain the rbtree and use it to speed up free_memtype() which
doesn't have the same bug(as we know what exactly we are searching for
in free_memtype).

Also use list_for_each_entry_from() in free_memtype() so that we start
the search from rb-tree lookup result.
Reported-by: NMarkus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
LKML-Reference: <1253136483.4119.12.camel@sbs-t61.sc.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>