ACPICA commit e25d791e4b3d5b9f4ead298269610cb05f89749a

There is a facility in Linux, developers can obtain GPE and fixed event
status via /sys/firmware/interrupts/. This is implemented using
acpi_get_event_status() and acpi_get_gpe_status(). Recently while debugging some
GPE race issues, it is found that the facility is lacking in the ability to
obtain real hardware register values, the confusing information makes
debugging difficult.

This patch modifies acpi_get_gpe_status() to return EN register values to fix
this gap. Then flags returned from acpi_get_event_status() and
acpi_get_gpe_status() are also cleaned up to reflect this change.

The old ACPI_EVENT_FLAG_SET is carefully kept to avoid regressions. It can
be deleted after we can make sure all its references are removed from OSPM
code. Lv Zheng.

Link: https://github.com/acpica/acpica/commit/e25d791eSigned-off-by: NLv Zheng <lv.zheng@intel.com>
Signed-off-by: NBob Moore <robert.moore@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPICA commit c70434d4da13e65b6163c79a5aa16b40193631c7

ACPI_MTX_TABLES is acquired and released by the callers of
acpi_tb_install_standard_table() so releasing it in the function itself is
causing the following error in Linux kernel if the table is reloaded:

ACPI Error: Mutex [0x2] is not acquired, cannot release (20141107/utmutex-321)
Call Trace:
  [<ffffffff81b0bd48>] dump_stack+0x4f/0x7b
  [<ffffffff81546bf5>] acpi_ut_release_mutex+0x47/0x67
  [<ffffffff81544357>] acpi_load_table+0x73/0xcb

Link: https://github.com/acpica/acpica/commit/c70434d4Signed-off-by: NOctavian Purdila <octavian.purdila@intel.com>
Signed-off-by: NLv Zheng <lv.zheng@intel.com>
Signed-off-by: NBob Moore <robert.moore@intel.com>
Cc: 3.16+ <stable@vger.kernel.org> # 3.16+
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPICA commit aacf863cfffd46338e268b7415f7435cae93b451

It is reported that on a physically 64-bit addressed machine, 32-bit kernel
can trigger crashes in accessing the memory regions that are beyond the
32-bit boundary. The region field's start address should still be 32-bit
compliant, but after a calculation (adding some offsets), it may exceed the
32-bit boundary. This case is rare and buggy, but there are real BIOSes
leaked with such issues (see References below).

This patch fixes this gap by always defining IO addresses as 64-bit, and
allows OSPMs to optimize it for a real 32-bit machine to reduce the size of
the internal objects.

Internal acpi_physical_address usages in the structures that can be fixed
by this change include:
 1. struct acpi_object_region:
    acpi_physical_address		address;
 2. struct acpi_address_range:
    acpi_physical_address		start_address;
    acpi_physical_address		end_address;
 3. struct acpi_mem_space_context;
    acpi_physical_address		address;
 4. struct acpi_table_desc
    acpi_physical_address		address;
See known issues 1 for other usages.

Note that acpi_io_address which is used for ACPI_PROCESSOR may also suffer
from same problem, so this patch changes it accordingly.

For iasl, it will enforce acpi_physical_address as 32-bit to generate
32-bit OSPM compatible tables on 32-bit platforms, we need to define
ACPI_32BIT_PHYSICAL_ADDRESS for it in acenv.h.

Known issues:
 1. Cleanup of mapped virtual address
   In struct acpi_mem_space_context, acpi_physical_address is used as a virtual
   address:
    acpi_physical_address                   mapped_physical_address;
   It is better to introduce acpi_virtual_address or use acpi_size instead.
   This patch doesn't make such a change. Because this should be done along
   with a change to acpi_os_map_memory()/acpi_os_unmap_memory().
   There should be no functional problem to leave this unchanged except
   that only this structure is enlarged unexpectedly.

Link: https://github.com/acpica/acpica/commit/aacf863c
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=87971
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=79501Reported-and-tested-by: NPaul Menzel <paulepanter@users.sourceforge.net>
Reported-and-tested-by: NSial Nije <sialnije@gmail.com>
Signed-off-by: NLv Zheng <lv.zheng@intel.com>
Signed-off-by: NBob Moore <robert.moore@intel.com>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPICA commit b60612373a4ef63b64a57c124576d7ddb6d8efb6

For physical addresses, since the address may exceed 32-bit address range
after calculation, we should use 0x%8.8X%8.8X instead of ACPI_PRINTF_UINT
and ACPI_FORMAT_UINT64() instead of
ACPI_FORMAT_NATIVE_UINT()/ACPI_FORMAT_TO_UINT().

This patch also removes above replaced macros as there are no users.

This is a preparation to switch acpi_physical_address to 64-bit on 32-bit
kernel builds.

Link: https://github.com/acpica/acpica/commit/b6061237Signed-off-by: NLv Zheng <lv.zheng@intel.com>
Signed-off-by: NBob Moore <robert.moore@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPICA commit 7f06739db43a85083a70371c14141008f20b2198

For physical addresses, since the address may exceed 32-bit address range
after calculation, we should use %8.8X%8.8X (see ACPI_FORMAT_UINT64()) to
convert the %p formats.

This is a preparation to switch acpi_physical_address to 64-bit on 32-bit
kernel builds.

Link: https://github.com/acpica/acpica/commit/7f06739dSigned-off-by: NLv Zheng <lv.zheng@intel.com>
Signed-off-by: NBob Moore <robert.moore@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPICA commit 154f6d074dd38d6ebc0467ad454454e6c5c9ecdf

There are code pieces converting pointers using "(acpi_physical_address) x"
or "ACPI_CAST_PTR (t, x)" formats, this patch cleans up them.

Known issues:
1. Cleanup of "(ACPI_PHYSICAL_ADDRRESS) x" for a table field
   For the conversions around the table fields, it is better to fix it with
   alignment also fixed. So this patch doesn't modify such code. There
   should be no functional problem by leaving them unchanged.

Link: https://github.com/acpica/acpica/commit/154f6d07Signed-off-by: NLv Zheng <lv.zheng@intel.com>
Signed-off-by: NBob Moore <robert.moore@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPICA commit c327986430b7eb170c17d0f45735fe71bb62a810

The conversion converts an acpi_physical_address to acpi_physical_address,
this patch thus removes such useless conversion.

Link: https://github.com/acpica/acpica/commit/c3279864Signed-off-by: NLv Zheng <lv.zheng@intel.com>
Signed-off-by: NBob Moore <robert.moore@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPICA commit 9e2d8180f4d5e61949b17513bae8aff6412f62dd

The offset calculation needn't convert a pointer to a special integer type.
So this patch uses ACPI_TO_INTEGER() instead.

This patch only affects acpidump tool.

Link: https://github.com/acpica/acpica/commit/9e2d8180Signed-off-by: NLv Zheng <lv.zheng@intel.com>
Signed-off-by: NBob Moore <robert.moore@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPICA commit 7d9fd64397d7c38899d3dc497525f6e6b044e0e3

OSPMs like Linux expect an acpi_physical_address returning value from
acpi_find_root_pointer(). This triggers warnings if sizeof (acpi_size) doesn't
equal to sizeof (acpi_physical_address):
  drivers/acpi/osl.c:275:3: warning: passing argument 1 of 'acpi_find_root_pointer' from incompatible pointer type [enabled by default]
  In file included from include/acpi/acpi.h:64:0,
                   from include/linux/acpi.h:36,
                   from drivers/acpi/osl.c:41:
  include/acpi/acpixf.h:433:1: note: expected 'acpi_size *' but argument is of type 'acpi_physical_address *'
This patch corrects acpi_find_root_pointer().

Link: https://github.com/acpica/acpica/commit/7d9fd643Signed-off-by: NLv Zheng <lv.zheng@intel.com>
Signed-off-by: NBob Moore <robert.moore@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch reduces source code differences between the Linux kernel and the
ACPICA upstream so that the linuxized ACPICA 20150410 release can be
applied with reduced human intervention.
Signed-off-by: NLv Zheng <lv.zheng@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Pull vfs and fs fixes from Al Viro:
 "Several AIO and OCFS2 fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  ocfs2: _really_ sync the right range
  ocfs2_file_write_iter: keep return value and current position update in sync
  [regression] ocfs2: do *not* increment ->ki_pos twice
  ioctx_alloc(): fix vma (and file) leak on failure
  fix mremap() vs. ioctx_kill() race

Pull last minute thermal-SoC management fixes from Eduardo Valentin:
 "Specifics:

   - Minor fixes on ST and RCAR thermal drivers.
   - Avoid flooding kernel log when driver returns -EAGAIN.

  Note: I am sending this pull on Rui's behalf while he fixes issues in
  his Linux box"

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/evalenti/linux-soc-thermal:
  drivers: thermal: st: remove several sparse warnings
  thermal: constify of_device_id array
  thermal: Do not log an error if thermal_zone_get_temp returns -EAGAIN
  thermal: rcar: Fix typo in r8a73a4 SoC name

Pull last-minute ASoC fix from Mark Brown:
 "This patch backs out a change that came in during the merge window
  which selects a configuration for GPIO4 on pcm512x CODECs that may not
  be suitable for all systems using the device.  Changes for v4.1 will
  make this properly configurable but for now it's safest to revert to
  the v3.19 behaviour and leave the pin configuration alone.

  Sorry for sending this direct at the last minute but due to the GPIO
  misuse it'd be really good to get it in the release and I'd not
  realised it hadn't been sent yet - between some travel, a job change
  and other non-urgent fixes coming in I'd lost track of the urgency.

  It's been in -next for several weeks now, is isolated to the driver
  and fairly clear to inspection"

* tag 'asoc-fix-v4.0-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound:
  ASoC: pcm512x: Remove hardcoding of pll-lock to GPIO4

Currently GPIO4 is hardcoded to output the pll-lock signal.
Unfortunately this is after the pll-out GPIO is configured which
is selectable in the device tree. Therefore it is not possible to
use GPIO4 for pll-out. Therefore this patch removes the
configuration of GPIO4.
Signed-off-by: NHoward Mitchell <hm@hmbedded.co.uk>
Signed-off-by: NMark Brown <broonie@kernel.org>

This reverts commit ecc19d17.

It added a new warning to try to encourage driver writers to set the
device capabities properly, but drivers haven't been updated and in the
meantime it just generaters a scary message that users cannot actually
do anything about.

Warnings like these are appropriate if you actually expect to fix the
code that causes them.  They are not appropriate for releases.
Requested-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Jan Engelhardt reports a strange oops with an invalid ->sense_buffer
pointer in scsi_init_cmd_errh() with the blk-mq code.

The sense_buffer pointer should have been initialized by the call to
scsi_init_request() from blk_mq_init_rq_map(), but there seems to be
some non-repeatable memory corruptor.

This patch makes sure we initialize the whole struct request allocation
(and the associated 'struct scsi_cmnd' for the SCSI case) to zero, by
using __GFP_ZERO in the allocation.  The old code initialized a couple
of individual fields, leaving the rest undefined (although many of them
are then initialized in later phases, like blk_mq_rq_ctx_init() etc.

It's not entirely clear why this matters, but it's the rigth thing to do
regardless, and with 4.0 imminent this is the defensive "let's just make
sure everything is initialized properly" patch.
Tested-by: NJan Engelhardt <jengelh@inai.de>
Acked-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull dmaengine fix from Vinod Koul:
 "I have one more fix to fix the boot warning on cppi driver due to
  missing capabilities"

* 'fixes' of git://git.infradead.org/users/vkoul/slave-dma:
  dmaengine: cppi41: add missing bitfields

Pull late ipmi fixes from Corey Minyard:
 "Some annoying issues in the IPMI driver that would be good to have
  fixed before 4.0 is released.

  These got reported or discovered late, but they will avoid some
  situations that would cause lots of log spam and in one case a
  deadlock"

* tag 'for-linus-4.0-1' of git://git.code.sf.net/p/openipmi/linux-ipmi:
  ipmi_ssif: Use interruptible completion for waiting in the thread
  ipmi/powernv: Fix minor locking bug
  ipmi: Handle BMCs that don't allow clearing the rcv irq bit

Add missing directions, residue_granularity,
srd_addr_widths and dst_addr_widths bitfields.

Without those we will see a kernel WARN()
when loading musb on am335x devices.
Signed-off-by: NFelipe Balbi <balbi@ti.com>
Signed-off-by: NVinod Koul <vinod.koul@intel.com>

The code was using an normal completion, but that caused stuck
task errors after a while.  Use an interruptible one to avoid that.
Signed-off-by: NCorey Minyard <cminyard@mvista.com>

If ipmi_powernv_recv(...) is called without a current message it
prints a warning and returns. However it fails to release the message
lock causing the system to dead lock during any subsequent IPMI
operations.

This error path should never normally be taken unless there are bugs
elsewhere in the system.
Signed-off-by: NAlistair Popple <alistair@popple.id.au>
Signed-off-by: NCorey Minyard <cminyard@mvista.com>

Some BMCs don't let you clear the receive irq bit in the global
enables.  This is kind of silly, but they give an error if you
try to clear it.  Compensate for this by detecting the situation
and working around it.
Signed-off-by: NCorey Minyard <cminyard@mvista.com>
Tested-by: NThomas D <whissi@whissi.de>
Reviewed-by: NThomas D <whissi@whissi.de>

Pull SCSI fixes from James Bottomley:
 "This is our remaining set of three fixes for 4.0: two oops fixes(one
  for cable pulls triggering oopses and the other be2iscsi specific) and
  one warn on in sysfs on multipath devices using enclosures"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  Defer processing of REQ_PREEMPT requests for blocked devices
  be2iscsi: Fix kernel panic when device initialization fails
  enclosure: fix WARN_ON removing an adapter in multi-path devices

Pull SCSI target fixes from Nicholas Bellinger:
 "Just a few small fixes:

  Two from Andy, the first addresses a v4.0 target specific regression
  to a user visible configfs attribute, and the second adds a set of
  missing brackets around IPv6 discovery portal information within
  iscsi-target.

  And one from Mike that fixes an OOPs regression in traditional
  iscsi-target when an iovec allocation fails, that has been present
  since v3.10.y code.  (CC'd to stable)"

* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
  iscsi target: fix oops when adding reject pdu
  iscsi-target: TargetAddress in SendTargets should bracket ipv6 addresses
  target: Allow userspace to write 1 to attrib/emulate_fua_write

This fixes a oops due to a double list add when adding a reject PDU for
iscsit_allocate_iovecs allocation failures. The cmd has already been
added to the conn_cmd_list in iscsit_setup_scsi_cmd, so this has us call
iscsit_reject_cmd.

Note that for ERL0 the reject PDU is not actually sent, so this patch
is not completely tested. Just verified we do not oops. The problem is the
add reject functions return -1 which is returned all the way up to
iscsi_target_rx_thread which for ERL0 will drop the connection.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Cc: <stable@vger.kernel.org> # v3.10+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Pull sound fixes from Takashi Iwai:
 "Here are fixes gathered for 4.0-final; one FireFire endian fix, two
  USB-audio quirks, and three HD-audio quirks.

  All relatively small and device-specific fixes, should be pretty safe
  to apply"

* tag 'sound-4.0' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: usb - Creative USB X-Fi Pro SB1095 volume knob support
  ALSA: hda - Fix headphone pin config for Lifebook T731
  ALSA: bebob: fix to processing in big-endian machine for sending cue
  ALSA: hda/realtek - Make more stable to get pin sense for ALC283
  ALSA: usb-audio: don't try to get Benchmark DAC1 sample rate
  ALSA: hda/realtek - Support Dell headset mode for ALC256

Pull arch/nios2 fixes from Ley Foon Tan:
 "There are 3 arch/nios2 fixes for 4.0 final:

   - fix cache coherency issue when debugging with gdb

   - move restart_block to struct task_struct (aligned with other
     architectures)

   - fix for missing registers defines for ptrace"

* tag 'nios2-fixes-v4.0-final' of git://git.rocketboards.org/linux-socfpga-next:
  nios2: fix cache coherency issue when debug with gdb
  nios2: add missing ptrace registers defines
  nios2: signal: Move restart_block to struct task_struct

Remove the end address checking for flushda function. We need to flush
each address line for flushda instruction, from start to end address.
This is because flushda instruction only flush the cache if tag and line
fields are matched.

Change to use ldwio instruction (bypass cache) to load the instruction
that causing trap. Our interest is the actual instruction that executed
by the processor, this should be uncached.
Note, EA address might be an userspace cached address.
Signed-off-by: NLey Foon Tan <lftan@altera.com>

Pull power management and ACPI fixes from Rafael Wysocki:
 "These are stable-candidate fixes of some recently reported issues in
  the cpufreq core, cpuidle core, the ACPI cpuidle driver and the
  hibernate core.

  Specifics:

   - Revert a 3.17 hibernate commit that was supposed to fix an issue
     related to e820 reserved regions, but broke resume from hibernation
     on Lenovo x230 (Rafael J Wysocki).

   - Prevent the ACPI cpuidle driver from overwriting the name and
     description of the C0 state set by the core when the list of
     C-states changes (Thomas Schlichter).

   - Remove the no longer needed state_count field from struct
     cpuidle_device which prevents the list of C-states shown by the
     sysfs interface from becoming incorrect when the current number of
     them is different from the number of C-states on boot (Bartlomiej
     Zolnierkiewicz).

   - The cpufreq core updates the policy object of the only online CPU
     during system resume to make it reflect the current hardware state,
     but it always assumes that CPU to be CPU0 which need not be the
     case, so fix the code to avoid that assumption (Viresh Kumar)"

* tag 'pm+acpi-4.0-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  Revert "PM / hibernate: avoid unsafe pages in e820 reserved regions"
  cpuidle: ACPI: do not overwrite name and description of C0
  cpuidle: remove state_count field from struct cpuidle_device
  cpufreq: Schedule work for the first-online CPU on resume

* pm-sleep:
  Revert "PM / hibernate: avoid unsafe pages in e820 reserved regions"

* pm-cpufreq:
  cpufreq: Schedule work for the first-online CPU on resume

* pm-cpuidle:
  cpuidle: ACPI: do not overwrite name and description of C0
  cpuidle: remove state_count field from struct cpuidle_device

Pull PCI fixes from Bjorn Helgaas:
 "Here are some fixes for v4.0.  I apologize for how late they are.  We
  were hoping for some better fixes, but couldn't get them polished in
  time.  These fix:

   - a Xen domU oops with PCI passthrough devices
   - a sparc T5 boot failure
   - a STM SPEAr13xx crash (use after initdata freed)
   - a cpcihp hotplug driver thinko
   - an AER thinko that printed stack junk

  Details:

  Enumeration
    - Don't look for ACPI hotplug parameters if ACPI is disabled (Bjorn Helgaas)

  Resource management
    - Revert "sparc/PCI: Clip bridge windows to fit in upstream windows" (Bjorn Helgaas)

  AER
    - Avoid info leak in __print_tlp_header() (Rasmus Villemoes)

  PCI device hotplug
    - Add missing curly braces in cpci_configure_slot() (Dan Carpenter)

  ST Microelectronics SPEAr13xx host bridge driver
    - Drop __initdata from spear13xx_pcie_driver (Matwey V. Kornilov)

* tag 'pci-v4.0-fixes-3' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  Revert "sparc/PCI: Clip bridge windows to fit in upstream windows"
  PCI: Don't look for ACPI hotplug parameters if ACPI is disabled
  PCI: cpcihp: Add missing curly braces in cpci_configure_slot()
  PCI/AER: Avoid info leak in __print_tlp_header()
  PCI: spear: Drop __initdata from spear13xx_pcie_driver

Adds an entry for Creative USB X-Fi to the rc_config array in
mixer_quirks.c to allow use of volume knob on the device.
Adds support for newer X-Fi Pro card, known as "Model No. SB1095"
with USB ID "041e:3237"
Signed-off-by: NDmitry M. Fedin <dmitry.fedin@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

"ocfs2 syncs the wrong range" had been broken; prior to it the
code was doing the wrong thing in case of O_APPEND, all right,
but _after_ it we were syncing the wrong range in 100% cases.
*ppos, aka iocb->ki_pos is incremented prior to that point,
so we are always doing sync on the area _after_ the one we'd
written to.

Spotted by Joseph Qi <joseph.qi@huawei.com> back in January;
unfortunately, I'd missed his mail back then ;-/

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

These are all register available in nios2.
Signed-off-by: NLey Foon Tan <lftan@altera.com>

Pull drm fixes from Dave Airlie:
 "Final drm fixes: one core locking imbalance regression, and a bunch of
  i915 baytrail s/r fixes"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm: fix drm_mode_getconnector() locking imbalance regression
  drm/i915/vlv: remove wait for previous GFX clk disable request
  drm/i915/chv: Remove Wait for a previous gfx force-off
  drm/i915/vlv: save/restore the power context base reg

Pull ceph revert from Sage Weil:
 "This corrects a recent misadventure with __GFP_MEMALLOC and
  PF_MEMALLOC; it turns out it's not a good fit for RBD and we're better
  off relying on dirty page throttling"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  Revert "libceph: use memalloc flags for net IO"

Merge misc fixes from Andrew Morton:
 "Three fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm: numa: disable change protection for vma(VM_HUGETLB)
  include/linux/dmapool.h: declare struct device
  mm: move zone lock to a different cache line than order-0 free page lists

Unlike most (all?) other copies from user space, kernel module loading
is almost unlimited in size.  So we do a potentially huge
"copy_from_user()" when we copy the module data from user space to the
kernel buffer, which can be a latency concern when preemption is
disabled (or voluntary).

Also, because 'copy_from_user()' clears the tail of the kernel buffer on
failures, even a *failed* copy can end up wasting a lot of time.

Normally neither of these are concerns in real life, but they do trigger
when doing stress-testing with trinity.  Running in a VM seems to add
its own overheadm causing trinity module load testing to even trigger
the watchdog.

The simple fix is to just chunk up the module loading, so that it never
tries to copy insanely big areas in one go.  That bounds the latency,
and also the amount of (unnecessarily, in this case) cleared memory for
the failure case.
Reported-by: NSasha Levin <sasha.levin@oracle.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The rule for 'copy_from_user()' is that it zeroes the remaining kernel
buffer even when the copy fails halfway, just to make sure that we don't
leave uninitialized kernel memory around.  Because even if we check for
errors, some kernel buffers stay around after thge copy (think page
cache).

However, the x86-64 logic for user copies uses a copy_user_generic()
function for all the cases, that set the "zerorest" flag for any fault
on the source buffer.  Which meant that it didn't just try to clear the
kernel buffer after a failure in copy_from_user(), it also tried to
clear the destination user buffer for the "copy_in_user()" case.

Not only is that pointless, it also means that the clearing code has to
worry about the tail clearing taking page faults for the user buffer
case.  Which is just stupid, since that case shouldn't happen in the
first place.

Get rid of the whole "zerorest" thing entirely, and instead just check
if the destination is in kernel space or not.  And then just use
memset() to clear the tail of the kernel buffer if necessary.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>