While debug_dma_assert_idle() checks if a given *page* is actively
undergoing dma the valid granularity of a dma mapping is a *cacheline*.
Sander's testing shows that the warning message "DMA-API: exceeded 7
overlapping mappings of pfn..." is falsely triggering.  The test is
simply mapping multiple cachelines in a given page.

Ultimately we want overlap tracking to be valid as it is a real api
violation, so we need to track active mappings by cachelines.  Update
the active dma tracking to use the page-frame-relative cacheline of the
mapping as the key, and update debug_dma_assert_idle() to check for all
possible mapped cachelines for a given page.

However, the need to track active mappings is only relevant when the
dma-mapping is writable by the device.  In fact it is fairly standard
for read-only mappings to have hundreds or thousands of overlapping
mappings at once.  Limiting the overlap tracking to writable
(!DMA_TO_DEVICE) eliminates this class of false-positive overlap
reports.

Note, the radix gang lookup is sub-optimal.  It would be best if it
stopped fetching entries once the search passed a page boundary.
Nevertheless, this implementation does not perturb the original net_dma
failing case.  That is to say the extra overhead does not show up in
terms of making the failing case pass due to a timing change.

References:
  http://marc.info/?l=linux-netdev&m=139232263419315&w=2
  http://marc.info/?l=linux-netdev&m=139217088107122&w=2Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Reported-by: Dave Jones <davej@redhat.com>
Tested-by: Dave Jones <davej@redhat.com>
Tested-by: Sander Eikelenboom <linux@eikelenboom.it>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Francois Romieu <romieu@fr.zoreil.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit bf6bddf1 ("mm: introduce compaction and migration for
ballooned pages") introduces page_count(page) into memory compaction
which dereferences page->first_page if PageTail(page).

This results in a very rare NULL pointer dereference on the
aforementioned page_count(page).  Indeed, anything that does
compound_head(), including page_count() is susceptible to racing with
prep_compound_page() and seeing a NULL or dangling page->first_page
pointer.

This patch uses Andrea's implementation of compound_trans_head() that
deals with such a race and makes it the default compound_head()
implementation.  This includes a read memory barrier that ensures that
if PageTail(head) is true that we return a head page that is neither
NULL nor dangling.  The patch then adds a store memory barrier to
prep_compound_page() to ensure page->first_page is set.

This is the safest way to ensure we see the head page that we are
expecting, PageTail(page) is already in the unlikely() path and the
memory barriers are unfortunately required.

Hugetlbfs is the exception, we don't enforce a store memory barrier
during init since no race is possible.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Holger Kiehl <Holger.Kiehl@dwd.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

We're more or less collecting EDAC patches already anyway so let's hold it
down so that get_maintainer sees it too.
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Cc: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull drm fixes from Dave Airlie:
 "Not a huge amount happening, some MAINTAINERS updates, radeon, vmwgfx
  and tegra fixes"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/vmwgfx: avoid null pointer dereference at failure paths
  drm/vmwgfx: Make sure backing mobs are cleared when allocated. Update driver date.
  drm/vmwgfx: Remove some unused surface formats
  drm/radeon: enable speaker allocation setup on dce3.2
  drm/radeon: change audio enable logic
  drm/radeon: fix audio disable on dce6+
  drm/radeon: free uvd ring on unload
  drm/radeon: disable pll sharing for DP on DCE4.1
  drm/radeon: fix missing bo reservation
  drm/radeon: print the supported atpx function mask
  MAINTAINERS: update drm git tree entry
  MAINTAINERS: add entry for drm radeon driver
  drm/tegra: Add guard to avoid double disable/enable of RGB outputs
  gpu: host1x: do not check previously handled gathers
  drm/tegra: fix typo 'CONFIG_TEGRA_DRM_FBDEV'

Pull USB fixes from Greg KH:
 "Here are 2 USB patches for 3.14-rc5, one a new device id, and the
  other fixes a reported problem with threaded irqs and the USB EHCI
  driver"

* tag 'usb-3.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: ehci: fix deadlock when threadirqs option is used
  USB: ftdi_sio: add Cressi Leonardo PID

Merge tag 'driver-core-3.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull sysfs fix from Greg KH:
 "Here is a single sysfs fix for 3.14-rc5.  It fixes a reported problem
  with the namespace code in sysfs"

* tag 'driver-core-3.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  sysfs: fix namespace refcnt leak

Pull staging tree fixes from Greg KH:
 "Here are a few IIO fixes, and a new device id for a staging driver for
  3.14-rc5.  All have been in linux-next for a while, I did a final
  merge to get the IIO fixes into this tree, they were incorrectly in
  the char-misc tree for a few weeks, and I forgot to tell you to pull
  them from there.  This makes it a single pull request for you"

* tag 'staging-3.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: r8188eu: Add new device ID
  staging:iio:adc:MXS:LRADC: fix touchscreen statemachine
  iio:gyro: bug on L3GD20H gyroscope support
  iio: cm32181: Change cm32181 ambient light sensor driver
  iio: cm36651: Fix read/write integration time function.

more radeon fixes

* 'drm-fixes-3.14' of git://people.freedesktop.org/~agd5f/linux:
  drm/radeon: enable speaker allocation setup on dce3.2
  drm/radeon: change audio enable logic
  drm/radeon: fix audio disable on dce6+
  drm/radeon: free uvd ring on unload
  drm/radeon: disable pll sharing for DP on DCE4.1
  drm/radeon: fix missing bo reservation
  drm/radeon: print the supported atpx function mask

These I forgot about before, but need to get into 3.14-final.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull perf fixes from Ingo Molnar:
 "Misc fixes, most of them on the tooling side"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf tools: Fix strict alias issue for find_first_bit
  perf tools: fix BFD detection on opensuse
  perf: Fix hotplug splat
  perf/x86: Fix event scheduling
  perf symbols: Destroy unused symsrcs
  perf annotate: Check availability of annotate when processing samples

Merge tag 'vmwgfx-fixes-3.14-2014-03-02' of git://people.freedesktop.org/~thomash/linux into drm-fixes

A couple of minor fixes.

Pull request of 2014-03-02

* tag 'vmwgfx-fixes-3.14-2014-03-02' of git://people.freedesktop.org/~thomash/linux:
  drm/vmwgfx: avoid null pointer dereference at failure paths
  drm/vmwgfx: Make sure backing mobs are cleared when allocated. Update driver date.
  drm/vmwgfx: Remove some unused surface formats

vmw_takedown_otable_base() and vmw_mob_unbind() check for
potential vmw_fifo_reserve() failure and print error message,
but then immediately dereference NULL pointer.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>

Backing mob contents is propagated to user-space, so make sure backing
mobs are cleared when allocated. This also accidently fix rendering errors
with celestia when emulating legacy mode.

Also update driver date.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>

These formats are deprecated.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>

Pull x86 fixes from Peter Anvin:
 "The VMCOREINFO patch I'll pushing for this release to avoid having a
  release with kASLR and but without that information.

  I was hoping to include the FPU patches from Suresh, but ran into a
  problem (see other thread); will try to make them happen next week"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, kaslr: add missed "static" declarations
  x86, kaslr: export offset in VMCOREINFO ELF notes

Pull SCSI target fixes from Nicholas Bellinger:
 "The bulk of the series are bugfixes for qla2xxx target NPIV support
  that went in for v3.14-rc1.  Also included are a few DIF related
  fixes, a qla2xxx fix (Cc'ed to stable) from Greg W., and vhost/scsi
  protocol version related fix from Venkatesh.

  Also just a heads up that a series to address a number of issues with
  iser-target active I/O reset/shutdown is still being tested, and will
  be included in a separate -rc6 PULL request"

* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
  vhost/scsi: Check LUN structure byte 0 is set to 1, per spec
  qla2xxx: Fix kernel panic on selective retransmission request
  Target/sbc: Don't use sg as iterator in sbc_verify_read
  target: Add DIF sense codes in transport_generic_request_failure
  target/sbc: Fix sbc_dif_copy_prot addr offset bug
  tcm_qla2xxx: Fix NAA formatted name for NPIV WWPNs
  tcm_qla2xxx: Perform configfs depend/undepend for base_tpg
  tcm_qla2xxx: Add NPIV specific enable/disable attribute logic
  qla2xxx: Check + fail when npiv_vports_inuse exists in shutdown
  qla2xxx: Fix qlt_lport_register base_vha callback race

Pull slave-dma fixes from Vinod Koul:
 "This request brings you two small fixes.  First one for fixing
  dereference of freed descriptor and second for fixing sdma bindings
  for it to work for imx25.

  I was planning to send this about 10days ago but then I had to proceed
  on my paternity leave and didnt get chance to send this.  Now got a
  bit of time from dady duties :)"

* 'fixes' of git://git.infradead.org/users/vkoul/slave-dma:
  dma: sdma: Add imx25 compatible
  dma: ste_dma40: don't dereference free:d descriptor

Pull ACPI and power management fixes from Rafael Wysocki:
 "These three commits fix a recent intel_pstate regression and two old
  bugs that should be fixed in -stable too, one in the ACPI processor
  driver and one in the firmare loader.

  Specifics:

   - One of the recent intel_pstate driver fixes introduced a rounding
     error that on some systems causes the frequency to be stuck at the
     lowest level forever.  Fix from Dirk Brandewie.

   - The firmware_class driver's PM notifier doesn't handle the
     PM_RESTORE_PREPARE event during hibernation image restore and that
     leads to a deadlock on umhelper_sem in __usermodehelper_disable().
     Fix from Sebastian Capella.

   - acpi_processor_set_throttling() abuses set_cpus_allowed_ptr() in a
     nasty way which triggers the WARN_ON_ONCE() in wq_worker_waking_up()
     among other things.  Fix from Lan Tianyu"

* tag 'pm+acpi-3.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / processor: Rework processor throttling with work_on_cpu()
  PM / hibernate: Fix restore hang in freeze_processes()
  intel_pstate: Change busy calculation to use fixed point math.

Merge tag 'perf-urgent-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent

Pull perf/urgent build fixes for certain distro environments, from Arnaldo Carvalho de Melo:

  * Problem on recent gcc on x86-32 related to strict alias issue for
    find_first_bit (Jiri Olsa).

  * OpenSuSE: BFD detection problems related to not explicitely listing all
    required libraries (Andi Kleen)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge tag 'fixes-for-3.14d' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-linus

Jonathan writes:

Fourth set of IIO fixes for the 3.14 kernel.

A single line patch fixing a regression that was introduced in 3.13 in the
reworking of the mxs touch screen and ADC drivers to be interrupt rather
than polling driven.  It resulted in a stray double reporting of the release
coordinate in the touch screen driver.  The bug lay in the adc side
of the driver which left the statemachine in the wrong state.

Add a maintainers entry for the Armada DRM driver.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull device mapper fixes from Mike Snitzer:
 "A few dm-cache fixes, an invalid ioctl handling fix for dm multipath,
  a couple immutable biovec fixups for dm mirror, and a few dm-thin
  fixes.

  There will likely be additional dm-thin metadata and data resize fixes
  to include in 3.14-rc6 next week.

  Note to stable-minded folks: Immutable biovecs were introduced in
  3.14, so the related fixups for dm mirror are not needed in stable@
  kernels"

* tag 'dm-3.14-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm cache: fix truncation bug when mapping I/O to >2TB fast device
  dm thin: allow metadata space larger than supported to go unused
  dm mpath: fix stalls when handling invalid ioctls
  dm thin: fix the error path for the thin device constructor
  dm raid1: fix immutable biovec related BUG when retrying read bio
  dm io: fix I/O to multiple destinations
  dm thin: avoid metadata commit if a pool's thin devices haven't changed
  dm cache: do not add migration to completed list before unhooking bio
  dm cache: move hook_info into common portion of per_bio_data structure

Pull sound fixes from Takashi Iwai:
 "It's a bad habit to get a higher volume of fixes often lately, but
  things happen again.

  All commits found here are real bug fixes, and are mostly trivial.
  Most of changes in ASoC are the fixes for enum items due to the wrong
  API usages, in addition to a few DAPM mutex deadlock and other fixes.
  In HD-audio, only fixups for HP laptops.  Although diffstat shows
  much, the changes are simple: there are just so many different device
  entries there"

* tag 'sound-3.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ASoC: sta32x: Fix wrong enum for limiter2 release rate
  ASoC: da732x: Mark DC offset control registers volatile
  ALSA: hda/realtek - Add more entry for enable HP mute led
  ALSA: hda - Add a fixup for HP Folio 13 mute LED
  ASoC: wm8958-dsp: Fix firmware block loading
  ASoC: sta32x: Fix cache sync
  ALSA: hda/realtek - Add more entry for enable HP mute led
  ASoC: dapm: Add locking to snd_soc_dapm_xxxx_pin functions
  Input - arizona-haptics: Fix double lock of dapm_mutex
  ASoC: wm8400: Fix the wrong number of enum items
  ASoC: isabelle: Fix the wrong number of items in enum ctls
  ASoC: ad1980: Fix wrong number of items for capture source
  ASoC: wm8994: Fix the wrong number of enum items
  ASoC: wm8900: Fix the wrong number of enum items
  ASoC: wm8770: Fix wrong number of enum items
  ASoC: sta32x: Fix array access overflow
  ASoC: dapm: Correct regulator bypass error messages

Pull EDAC fixes from Borislav Petkov:
 "Two fixes below for PCI devices disappearing when a reference count
  underflow happens after a couple of insmod/rmmod cycles in succession"

* tag 'edac_fixes_for_3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp:
  i7300_edac: Fix device reference count
  i7core_edac: Fix PCI device reference count

Pull KVM fixes from Paolo Bonzini:
 "Three x86 fixes and one for ARM/ARM64.

  In particular, nested virtualization on Intel is broken in 3.13 and
  fixed by this pull request"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  kvm, vmx: Really fix lazy FPU on nested guest
  kvm: x86: fix emulator buffer overflow (CVE-2014-0049)
  arm/arm64: KVM: detect CPU reset on CPU_PM_EXIT
  KVM: MMU: drop read-only large sptes when creating lower level sptes

Pull ARM64 fixes from Catalin Marinas:
 - !CONFIG_SMP build fix
 - pte bit testing macros conversion fix (int truncates top bits of
   long)
 - stack unwinding PC calculation fix

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: Fix !CONFIG_SMP kernel build
  arm64: mm: Add double logical invert to pte accessors
  ARM64: unwind: Fix PC calculation

Pull powerpc fixes from Ben Herrenschmidt:
 "Here are a few more powerpc fixes for 3.14.

  Most of these are also CC'ed to stable and fix bugs in new
  functionality introduced in the last 2 or 3 versions"

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc/powernv: Fix indirect XSCOM unmangling
  powerpc/powernv: Fix opal_xscom_{read,write} prototype
  powerpc/powernv: Refactor PHB diag-data dump
  powerpc/powernv: Dump PHB diag-data immediately
  powerpc: Increase stack redzone for 64-bit userspace to 512 bytes
  powerpc/ftrace: bugfix for test_24bit_addr
  powerpc/crashdump : Fix page frame number check in copy_oldmem_page
  powerpc/le: Ensure that the 'stop-self' RTAS token is handled correctly

Commit fb4a9602 (arm64: kernel: fix per-cpu offset restore on
resume) uses per_cpu_offset() unconditionally during CPU wakeup,
however, this is only defined for the SMP case.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Dave P Martin <Dave.Martin@arm.com>

Page table entries on ARM64 are 64 bits, and some pte functions such as
pte_dirty return a bitwise-and of a flag with the pte value. If the
flag to be tested resides in the upper 32 bits of the pte, then we run
into the danger of the result being dropped if downcast.

For example:
	gather_stats(page, md, pte_dirty(*pte), 1);
where pte_dirty(*pte) is downcast to an int.

This patch adds a double logical invert to all the pte_ accessors to
ensure predictable downcasting.
Signed-off-by: Steve Capper <steve.capper@linaro.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

When remapping a block to the cache's fast device that is larger than
2TB we must not truncate the destination sector to 32bits.  The 32bit
temporary result of from_cblock() was being overflowed in
remap_to_cache() due to the logical left shift.

Use an intermediate 64bit type to store the 32bit from_cblock() result
to fix the overflow.
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org

When compiling perf tool code with gcc 4.4.7 I'm getting
following error:

    CC       util/session.o
  cc1: warnings being treated as errors
  util/session.c: In function ‘perf_session_deliver_event’:
  tools/perf/util/include/linux/bitops.h:109: error: dereferencing pointer ‘p’ does break strict-aliasing rules
  tools/perf/util/include/linux/bitops.h:101: error: dereferencing pointer ‘p’ does break strict-aliasing rules
  util/session.c:697: note: initialized from here
  tools/perf/util/include/linux/bitops.h:101: note: initialized from here
  make[1]: *** [util/session.o] Error 1
  make: *** [util/session.o] Error 2

The aliased types here are u64 and unsigned long pointers, which is safe
for the find_first_bit processing.

This error shows up for me only for gcc 4.4 on 32bit x86, even for
-Wstrict-aliasing=3, while newer gcc are quiet and scream here for
-Wstrict-aliasing={2,1}. Looks like newer gcc changed the rules for
strict alias warnings.

The gcc documentation offers workaround for valid aliasing by using
__may_alias__ attribute:

  http://gcc.gnu.org/onlinedocs/gcc-4.4.0/gcc/Type-Attributes.html

Using this workaround for the find_first_bit function.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1393434867-20271-1-git-send-email-jolsa@redhat.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

We need to unmangle the full address, not just the register
number, and we also need to support the real indirect bit
being set for in-kernel uses.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: <stable@vger.kernel.org> [v3.13]

The OPAL firmware functions opal_xscom_read and opal_xscom_write
take a 64-bit argument for the XSCOM (PCB) address in order to
support the indirect mode on P8.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: <stable@vger.kernel.org> [v3.13]

As Ben suggested, the patch prints PHB diag-data with multiple
fields in one line and omits the line if the fields of that
line are all zero.

With the patch applied, the PHB3 diag-data dump looks like:

PHB3 PHB#3 Diag-data (Version: 1)

  brdgCtl:     00000002
  RootSts:     0000000f 00400000 b0830008 00100147 00002000
  nFir:        0000000000000000 0030006e00000000 0000000000000000
  PhbSts:      0000001c00000000 0000000000000000
  Lem:         0000000000100000 42498e327f502eae 0000000000000000
  InAErr:      8000000000000000 8000000000000000 0402030000000000 0000000000000000
  PE[  8] A/B: 8480002b00000000 8000000000000000

[ The current diag data is so big that it overflows the printk
  buffer pretty quickly in cases when we get a handful of errors
  at once which can happen. --BenH
]
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
CC: <stable@vger.kernel.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

The PHB diag-data is important to help locating the root cause for
EEH errors such as frozen PE or fenced PHB. However, the EEH core
enables IO path by clearing part of HW registers before collecting
this data causing it to be corrupted.

This patch fixes this by dumping the PHB diag-data immediately when
frozen/fenced state on PE or PHB is detected for the first time in
eeh_ops::get_state() or next_error() backend.
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
CC: <stable@vger.kernel.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

The new ELFv2 little-endian ABI increases the stack redzone -- the
area below the stack pointer that can be used for storing data --
from 288 bytes to 512 bytes.  This means that we need to allow more
space on the user stack when delivering a signal to a 64-bit process.

To make the code a bit clearer, we define new USER_REDZONE_SIZE and
KERNEL_REDZONE_SIZE symbols in ptrace.h.  For now, we leave the
kernel redzone size at 288 bytes, since increasing it to 512 bytes
would increase the size of interrupt stack frames correspondingly.

Gcc currently only makes use of 288 bytes of redzone even when
compiling for the new little-endian ABI, and the kernel cannot
currently be compiled with the new ABI anyway.

In the future, hopefully gcc will provide an option to control the
amount of redzone used, and then we could reduce it even more.

This also changes the code in arch_compat_alloc_user_space() to
preserve the expanded redzone.  It is not clear why this function would
ever be used on a 64-bit process, though.
Signed-off-by: Paul Mackerras <paulus@samba.org>
CC: <stable@vger.kernel.org> [v3.13]
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

The branch target should be the func addr, not the addr of func_descr_t.
So using ppc_function_entry() to generate the right target addr.
Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

In copy_oldmem_page, the current check using max_pfn and min_low_pfn to
decide if the page is backed or not, is not valid when the memory layout is
not continuous.

This happens when running as a QEMU/KVM guest, where RTAS is mapped higher
in the memory. In that case max_pfn points to the end of RTAS, and a hole
between the end of the kdump kernel and RTAS is not backed by PTEs. As a
consequence, the kdump kernel is crashing in copy_oldmem_page when accessing
in a direct way the pages in that hole.

This fix relies on the memblock's service memblock_is_region_memory to
check if the read page is part or not of the directly accessible memory.
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Tested-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
CC: <stable@vger.kernel.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Currently we're storing a host endian RTAS token in
rtas_stop_self_args.token.  We then pass that directly to rtas.  This is
fine on big endian however on little endian the token is not what we
expect.

This will typically result in hitting:
	panic("Alas, I survived.\n");

To fix this we always use the stop-self token in host order and always
convert it to be32 before passing this to rtas.
Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>