Optimized version that make use of the l.lwa and l.swa atomic instruction
pair.
Most openrisc cores provide these instructions now, if not available
emulation is provided.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
[shorne@gmail.com: remove OPENRISC_HAVE_INST_LWA_SWA config suggesed by
Alan Cox https://lkml.org/lkml/2014/7/23/666]
[shorne@gmail.com: fixed unused calculated value compiler warning in
define cmpxchg]
Signed-off-by: Stafford Horne <shorne@gmail.com>

This utilize the load-link/store-conditional l.lwa and l.swa
instructions to implement the atomic bitops.
When those instructions are not available emulation is provided.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
[shorne@gmail.com: remove OPENRISC_HAVE_INST_LWA_SWA config suggesed by
Alan Cox https://lkml.org/lkml/2014/7/23/666, implement
test_and_change_bit]
Signed-off-by: Stafford Horne <shorne@gmail.com>

This adds an emulation layer for implementations
that lack the l.lwa and l.swa instructions.
It handles these instructions both in kernel space and
user space.
Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
[shorne@gmail.com: Added delay slot pc adjust logic]
Signed-off-by: Stafford Horne <shorne@gmail.com>

This brings it inline with the other setup oprations done like the cache
enables _ic_enable and _dc_enable.  Also, this is going to make it
easier to initialize additional cpu's when smp is introduced.
Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
[shorne@gmail.com: Added commit body]
Signed-off-by: Stafford Horne <shorne@gmail.com>

The stack size was hard coded to 0x2000, use the standard THREAD_SIZE
definition loaded from thread_info.h.
Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
[shorne@gmail.com: Added body to the commit message]
Signed-off-by: Stafford Horne <shorne@gmail.com>

By slightly reorganizing the code, the number of registers
used in the tlb miss handlers can be reduced by two,
thus removing the need to save them to memory.

Also, some dead and commented out code is removed.

No functional change.
Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Signed-off-by: Jonas Bonn <jonas@southpole.se>
Signed-off-by: Stafford Horne <shorne@gmail.com>

Motivation for this is to be able to print the way information
properly in print_cpuinfo(), instead of hardcoding it to one.
Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Signed-off-by: Jonas Bonn <jonas@southpole.se>
[shorne@gmail.com fixed conflict with show_cpuinfo change]
Signed-off-by: Stafford Horne <shorne@gmail.com>

The sparse IRQ framework is preferred nowadays so switch over to it.
Signed-off-by: Jonas Bonn <jonas@southpole.se>
Signed-off-by: Stafford Horne <shorne@gmail.com>

Pull irq fixes from Thomas Gleixner:

 - Prevent double activation of interrupt lines, which causes problems
   on certain interrupt controllers

 - Handle the fallout of the above because x86 (ab)uses the activation
   function to reconfigure interrupts under the hood.

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/irq: Make irq activate operations symmetric
  irqdomain: Avoid activating interrupts more than once

Pull KVM fix from Radim Krčmář:
 "Fix a regression that prevented migration between hosts with different
  XSAVE features even if the missing features were not used by the guest
  (for stable)"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86: do not save guest-unsupported XSAVE state

Pull char/misc driver fixes from Greg KH:
 "Here are two bugfixes that resolve some reported issues. One in the
  firmware loader, that should fix the much-reported problem of crashes
  with it. The other is a hyperv fix for a reported regression.

  Both have been in linux-next for a week or so with no reported issues"

* tag 'char-misc-4.10-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  Drivers: hv: vmbus: finally fix hv_need_to_signal_on_read()
  firmware: fix NULL pointer dereference in __fw_load_abort()

Pull staging/IIO fixes from Greg KH:
 "Here are a few small IIO and one staging driver fix for 4.10-rc7. They
  fix some reported issues with the drivers.

  All of them have been in linux-next for a week or so with no reported
  issues"

* tag 'staging-4.10-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: greybus: timesync: validate platform state callback
  iio: dht11: Use usleep_range instead of msleep for start signal
  iio: adc: palmas_gpadc: retrieve a valid iio_dev in suspend/resume
  iio: health: max30100: fixed parenthesis around FIFO count check
  iio: health: afe4404: retrieve a valid iio_dev in suspend/resume
  iio: health: afe4403: retrieve a valid iio_dev in suspend/resume

Pull USB fixes from Greg KH:
 "Here are some small USB fixes for some reported issues, and the usual
  number of new device ids for 4.10-rc7.

  All of these, except the last new device id, have been in linux-next
  for a while with no reported issues"

* tag 'usb-4.10-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  USB: serial: pl2303: add ATEN device ID
  usb: gadget: f_fs: Assorted buffer overflow checks.
  USB: Add quirk for WORLDE easykey.25 MIDI keyboard
  usb: musb: Fix external abort on non-linefetch for musb_irq_work()
  usb: musb: Fix host mode error -71 regression
  USB: serial: option: add device ID for HP lt2523 (Novatel E371)
  USB: serial: qcserial: add Dell DW5570 QDL

Pull SCSI fix from James Bottomley:
 "A single fix this time: a fix for a virtqueue removal bug which only
  appears to affect S390, but which results in the queue hanging forever
  thus causing the machine to fail shutdown"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: virtio_scsi: Reject commands when virtqueue is broken

Pull virtio/vhost fixes from Michael S. Tsirkin:
 "Last minute fixes:

   - ARM DMA fix revert

   - vhost endian-ness fix

   - MAINTAINERS: email address change for Amit"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  MAINTAINERS: update email address for Amit Shah
  vhost: fix initialization for vq->is_le
  Revert "vring: Force use of DMA API for ARM-based systems with legacy devices"

Pull VFIO fix from Alex Williamson:
 "Fix an error path in SPAPR IOMMU backend (Alexey Kardashevskiy)"

* tag 'vfio-v4.10-rc7' of git://github.com/awilliam/linux-vfio:
  vfio/spapr: Fix missing mutex unlock when creating a window

Merge fixes from Andrew Morton:
 "8 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm, fs: check for fatal signals in do_generic_file_read()
  fs: break out of iomap_file_buffered_write on fatal signals
  base/memory, hotplug: fix a kernel oops in show_valid_zones()
  mm/memory_hotplug.c: check start_pfn in test_pages_in_a_zone()
  jump label: pass kbuild_cflags when checking for asm goto support
  shmem: fix sleeping from atomic context
  kasan: respect /proc/sys/kernel/traceoff_on_warning
  zswap: disable changing params if init fails

do_generic_file_read() can be told to perform a large request from
userspace.  If the system is under OOM and the reading task is the OOM
victim then it has an access to memory reserves and finishing the full
request can lead to the full memory depletion which is dangerous.  Make
sure we rather go with a short read and allow the killed task to
terminate.

Link: http://lkml.kernel.org/r/20170201092706.9966-3-mhocko@kernel.orgSigned-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Tetsuo has noticed that an OOM stress test which performs large write
requests can cause the full memory reserves depletion.  He has tracked
this down to the following path

	__alloc_pages_nodemask+0x436/0x4d0
	alloc_pages_current+0x97/0x1b0
	__page_cache_alloc+0x15d/0x1a0          mm/filemap.c:728
	pagecache_get_page+0x5a/0x2b0           mm/filemap.c:1331
	grab_cache_page_write_begin+0x23/0x40   mm/filemap.c:2773
	iomap_write_begin+0x50/0xd0             fs/iomap.c:118
	iomap_write_actor+0xb5/0x1a0            fs/iomap.c:190
	? iomap_write_end+0x80/0x80             fs/iomap.c:150
	iomap_apply+0xb3/0x130                  fs/iomap.c:79
	iomap_file_buffered_write+0x68/0xa0     fs/iomap.c:243
	? iomap_write_end+0x80/0x80
	xfs_file_buffered_aio_write+0x132/0x390 [xfs]
	? remove_wait_queue+0x59/0x60
	xfs_file_write_iter+0x90/0x130 [xfs]
	__vfs_write+0xe5/0x140
	vfs_write+0xc7/0x1f0
	? syscall_trace_enter+0x1d0/0x380
	SyS_write+0x58/0xc0
	do_syscall_64+0x6c/0x200
	entry_SYSCALL64_slow_path+0x25/0x25

the oom victim has access to all memory reserves to make a forward
progress to exit easier.  But iomap_file_buffered_write and other
callers of iomap_apply loop to complete the full request.  We need to
check for fatal signals and back off with a short write instead.

As the iomap_apply delegates all the work down to the actor we have to
hook into those.  All callers that work with the page cache are calling
iomap_write_begin so we will check for signals there.  dax_iomap_actor
has to handle the situation explicitly because it copies data to the
userspace directly.  Other callers like iomap_page_mkwrite work on a
single page or iomap_fiemap_actor do not allocate memory based on the
given len.

Fixes: 68a9f5e7 ("xfs: implement iomap based buffered write path")
Link: http://lkml.kernel.org/r/20170201092706.9966-2-mhocko@kernel.orgSigned-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>	[4.8+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Reading a sysfs "memoryN/valid_zones" file leads to the following oops
when the first page of a range is not backed by struct page.
show_valid_zones() assumes that 'start_pfn' is always valid for
page_zone().

 BUG: unable to handle kernel paging request at ffffea017a000000
 IP: show_valid_zones+0x6f/0x160

This issue may happen on x86-64 systems with 64GiB or more memory since
their memory block size is bumped up to 2GiB.  [1] An example of such
systems is desribed below.  0x3240000000 is only aligned by 1GiB and
this memory block starts from 0x3200000000, which is not backed by
struct page.

 BIOS-e820: [mem 0x0000003240000000-0x000000603fffffff] usable

Since test_pages_in_a_zone() already checks holes, fix this issue by
extending this function to return 'valid_start' and 'valid_end' for a
given range.  show_valid_zones() then proceeds with the valid range.

[1] 'Commit bdee237c ("x86: mm: Use 2GB memory block size on
    large-memory x86-64 systems")'

Link: http://lkml.kernel.org/r/20170127222149.30893-3-toshi.kani@hpe.comSigned-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Zhang Zhen <zhenzhang.zhang@huawei.com>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: <stable@vger.kernel.org>	[4.4+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Patch series "fix a kernel oops when reading sysfs valid_zones", v2.

A sysfs memory file is created for each 2GiB memory block on x86-64 when
the system has 64GiB or more memory.  [1] When the start address of a
memory block is not backed by struct page, i.e.  a memory range is not
aligned by 2GiB, reading its 'valid_zones' attribute file leads to a
kernel oops.  This issue was observed on multiple x86-64 systems with
more than 64GiB of memory.  This patch-set fixes this issue.

Patch 1 first fixes an issue in test_pages_in_a_zone(), which does not
test the start section.

Patch 2 then fixes the kernel oops by extending test_pages_in_a_zone()
to return valid [start, end).

Note for stable kernels: The memory block size change was made by commit
bdee237c ("x86: mm: Use 2GB memory block size on large-memory x86-64
systems"), which was accepted to 3.9.  However, this patch-set depends
on (and fixes) the change to test_pages_in_a_zone() made by commit
5f0f2887 ("mm/memory_hotplug.c: check for missing sections in
test_pages_in_a_zone()"), which was accepted to 4.4.

So, I recommend that we backport it up to 4.4.

[1] 'Commit bdee237c ("x86: mm: Use 2GB memory block size on
    large-memory x86-64 systems")'

This patch (of 2):

test_pages_in_a_zone() does not check 'start_pfn' when it is aligned by
section since 'sec_end_pfn' is set equal to 'pfn'.  Since this function
is called for testing the range of a sysfs memory file, 'start_pfn' is
always aligned by section.

Fix it by properly setting 'sec_end_pfn' to the next section pfn.

Also make sure that this function returns 1 only when the range belongs
to a zone.

Link: http://lkml.kernel.org/r/20170127222149.30893-2-toshi.kani@hpe.comSigned-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Andrew Banman <abanman@sgi.com>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Greg KH <greg@kroah.com>
Cc: <stable@vger.kernel.org>	[4.4+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Some versions of ARM GCC compiler such as Android toolchain throws in a
'-fpic' flag by default.  This causes the gcc-goto check script to fail
although some config would have '-fno-pic' flag in the KBUILD_CFLAGS.

This patch passes the KBUILD_CFLAGS to the check script so that the
script does not rely on the default config from different compilers.

Link: http://lkml.kernel.org/r/20170120234329.78868-1-dtwlin@google.comSigned-off-by: David Lin <dtwlin@google.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Michal Marek <mmarek@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Syzkaller fuzzer managed to trigger this:

    BUG: sleeping function called from invalid context at mm/shmem.c:852
    in_atomic(): 1, irqs_disabled(): 0, pid: 529, name: khugepaged
    3 locks held by khugepaged/529:
     #0:  (shrinker_rwsem){++++..}, at: [<ffffffff818d7ef1>] shrink_slab.part.59+0x121/0xd30 mm/vmscan.c:451
     #1:  (&type->s_umount_key#29){++++..}, at: [<ffffffff81a63630>] trylock_super+0x20/0x100 fs/super.c:392
     #2:  (&(&sbinfo->shrinklist_lock)->rlock){+.+.-.}, at: [<ffffffff818fd83e>] spin_lock include/linux/spinlock.h:302 [inline]
     #2:  (&(&sbinfo->shrinklist_lock)->rlock){+.+.-.}, at: [<ffffffff818fd83e>] shmem_unused_huge_shrink+0x28e/0x1490 mm/shmem.c:427
    CPU: 2 PID: 529 Comm: khugepaged Not tainted 4.10.0-rc5+ #201
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
    Call Trace:
       shmem_undo_range+0xb20/0x2710 mm/shmem.c:852
       shmem_truncate_range+0x27/0xa0 mm/shmem.c:939
       shmem_evict_inode+0x35f/0xca0 mm/shmem.c:1030
       evict+0x46e/0x980 fs/inode.c:553
       iput_final fs/inode.c:1515 [inline]
       iput+0x589/0xb20 fs/inode.c:1542
       shmem_unused_huge_shrink+0xbad/0x1490 mm/shmem.c:446
       shmem_unused_huge_scan+0x10c/0x170 mm/shmem.c:512
       super_cache_scan+0x376/0x450 fs/super.c:106
       do_shrink_slab mm/vmscan.c:378 [inline]
       shrink_slab.part.59+0x543/0xd30 mm/vmscan.c:481
       shrink_slab mm/vmscan.c:2592 [inline]
       shrink_node+0x2c7/0x870 mm/vmscan.c:2592
       shrink_zones mm/vmscan.c:2734 [inline]
       do_try_to_free_pages+0x369/0xc80 mm/vmscan.c:2776
       try_to_free_pages+0x3c6/0x900 mm/vmscan.c:2982
       __perform_reclaim mm/page_alloc.c:3301 [inline]
       __alloc_pages_direct_reclaim mm/page_alloc.c:3322 [inline]
       __alloc_pages_slowpath+0xa24/0x1c30 mm/page_alloc.c:3683
       __alloc_pages_nodemask+0x544/0xae0 mm/page_alloc.c:3848
       __alloc_pages include/linux/gfp.h:426 [inline]
       __alloc_pages_node include/linux/gfp.h:439 [inline]
       khugepaged_alloc_page+0xc2/0x1b0 mm/khugepaged.c:750
       collapse_huge_page+0x182/0x1fe0 mm/khugepaged.c:955
       khugepaged_scan_pmd+0xfdf/0x12a0 mm/khugepaged.c:1208
       khugepaged_scan_mm_slot mm/khugepaged.c:1727 [inline]
       khugepaged_do_scan mm/khugepaged.c:1808 [inline]
       khugepaged+0xe9b/0x1590 mm/khugepaged.c:1853
       kthread+0x326/0x3f0 kernel/kthread.c:227
       ret_from_fork+0x31/0x40 arch/x86/entry/entry_64.S:430

The iput() from atomic context was a bad idea: if after igrab() somebody
else calls iput() and we left with the last inode reference, our iput()
would lead to inode eviction and therefore sleeping.

This patch should fix the situation.

Link: http://lkml.kernel.org/r/20170131093141.GA15899@node.shutemov.nameSigned-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

After much waiting I finally reproduced a KASAN issue, only to find my
trace-buffer empty of useful information because it got spooled out :/

Make kasan_report honour the /proc/sys/kernel/traceoff_on_warning
interface.

Link: http://lkml.kernel.org/r/20170125164106.3514-1-aryabinin@virtuozzo.comSigned-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add zswap_init_failed bool that prevents changing any of the module
params, if init_zswap() fails, and set zswap_enabled to false.  Change
'enabled' param to a callback, and check zswap_init_failed before
allowing any change to 'enabled', 'zpool', or 'compressor' params.

Any driver that is built-in to the kernel will not be unloaded if its
init function returns error, and its module params remain accessible for
users to change via sysfs.  Since zswap uses param callbacks, which
assume that zswap has been initialized, changing the zswap params after
a failed initialization will result in WARNING due to the param
callbacks expecting a pool to already exist.  This prevents that by
immediately exiting any of the param callbacks if initialization failed.

This was reported here:
  https://marc.info/?l=linux-mm&m=147004228125528&w=4

And fixes this WARNING:
  [  429.723476] WARNING: CPU: 0 PID: 5140 at mm/zswap.c:503 __zswap_pool_current+0x56/0x60

The warning is just noise, and not serious.  However, when init fails,
zswap frees all its percpu dstmem pages and its kmem cache.  The kmem
cache might be serious, if kmem_cache_alloc(NULL, gfp) has problems; but
the percpu dstmem pages are definitely a problem, as they're used as
temporary buffer for compressed pages before copying into place in the
zpool.

If the user does get zswap enabled after an init failure, then zswap
will likely Oops on the first page it tries to compress (or worse, start
corrupting memory).

Fixes: 90b0fc26 ("zswap: change zpool/compressor at runtime")
Link: http://lkml.kernel.org/r/20170124200259.16191-2-ddstreet@ieee.orgSigned-off-by: Dan Streetman <dan.streetman@canonical.com>
Reported-by: Marcin Miroslaw <marcin@mejor.pl>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge tag 'regulator-fix-v4.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator

Pull regulator fixes from Mark Brown:
 "Three changes here: two run of the mill driver specific fixes and a
  change from Mark Rutland which reverts some new device specific ACPI
  binding code which was added during the merge window as there are
  concerns about this sending the wrong signal about usage of regulators
  in ACPI systems"

* tag 'regulator-fix-v4.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator:
  regulator: fixed: Revert support for ACPI interface
  regulator: axp20x: AXP806: Fix dcdcb being set instead of dcdce
  regulator: twl6030: fix range comparison, allowing vsel = 59

I'm leaving my job at Red Hat, this email address will stop working next week.
Update it to one that I will have access to later.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Currently, under certain circumstances vhost_init_is_le does just a part
of the initialization job, and depends on vhost_reset_is_le being called
too. For this reason vhost_vq_init_access used to call vhost_reset_is_le
when vq->private_data is NULL. This is not only counter intuitive, but
also real a problem because it breaks vhost_net. The bug was introduced to
vhost_net with commit 2751c988 ("vhost: cross-endian support for
legacy devices"). The symptom is corruption of the vq's used.idx field
(virtio) after VHOST_NET_SET_BACKEND was issued as a part of the vhost
shutdown on a vq with pending descriptors.

Let us make sure the outcome of vhost_init_is_le never depend on the state
it is actually supposed to initialize, and fix virtio_net by removing the
reset from vhost_vq_init_access.

With the above, there is no reason for vhost_reset_is_le to do just half
of the job. Let us make vhost_reset_is_le reinitialize is_le.
Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reported-by: Michael A. Tebolt <miket@us.ibm.com>
Reported-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Fixes: commit 2751c988 ("vhost: cross-endian support for legacy devices")
Cc: <stable@vger.kernel.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Tested-by: Michael A. Tebolt <miket@us.ibm.com>

This reverts commit c7070619.

This has been shown to regress on some ARM systems:

by forcing on DMA API usage for ARM systems, we have inadvertently
kicked open a hornets' nest in terms of cache-coherency. Namely that
unless the virtio device is explicitly described as capable of coherent
DMA by firmware, the DMA APIs on ARM and other DT-based platforms will
assume it is non-coherent. This turns out to cause a big problem for the
likes of QEMU and kvmtool, which generate virtio-mmio devices in their
guest DTs but neglect to add the often-overlooked "dma-coherent"
property; as a result, we end up with the guest making non-cacheable
accesses to the vring, the host doing so cacheably, both talking past
each other and things going horribly wrong.

We are working on a safer work-around.

Fixes: c7070619 ("vring: Force use of DMA API for ARM-based systems with legacy devices")
Reported-by: Robin Murphy <robin.murphy@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>

Merge tag 'usb-serial-4.10-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial into usb-linus

Johan writes:

USB-serial fixes for v4.10-rc7

One more device ID for pl2303.
Signed-off-by: Johan Hovold <johan@kernel.org>

Pull MMC fix from Ulf Hansson:
 "MMC host: sdhci: Avoid hang when receiving spurious CARD_INT
  interrupts"

* tag 'mmc-v4.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc:
  mmc: sdhci: Ignore unexpected CARD_INT interrupts

Pull drm fixes from Dave Airlie:
 "Another fixes pull for v4.10, it's a bit big due to the backport of
  the VMA fixes for i915 that should fix the oops on shutdown problems
  that you've worked around.

  There are also two drm core connector registration fixes, a bunch of
  nouveau regression fixes and two AMD fixes"

* tag 'drm-fixes-for-v4.10-rc7' of git://people.freedesktop.org/~airlied/linux:
  drm/radeon: Fix vram_size/visible values in DRM_RADEON_GEM_INFO ioctl
  drm/amdgpu/si: fix crash on headless asics
  drm/i915: Track pinned vma in intel_plane_state
  drm/atomic: Unconditionally call prepare_fb.
  drm/atomic: Fix double free in drm_atomic_state_default_clear
  drm/nouveau/kms/nv50: request vblank events for commits that send completion events
  drm/nouveau/nv1a,nv1f/disp: fix memory clock rate retrieval
  drm/nouveau/disp/gt215: Fix HDA ELD handling (thus, HDMI audio) on gt215
  drm/nouveau/nouveau/led: prevent compiling the led-code if nouveau=y and leds=m
  drm/nouveau/disp/mcp7x: disable dptmds workaround
  drm/nouveau: prevent userspace from deleting client object
  drm/nouveau/fence/g84-: protect against concurrent access to semaphore buffers
  drm: Don't race connector registration
  drm: prevent double-(un)registration for connectors

Pull powerpc fixes from Michael Ellerman:
 "The main change is we're reverting the initial stack protector support
  we merged this cycle. It turns out to not work on toolchains built
  with libc support, and fixing it will be need to wait for another
  release.

  And the rest are all fairly minor:

   - Some pasemi machines were not booting due to a missing error check
     in prom_find_boot_cpu()

   - In EEH we were checking a pointer rather than the bool it pointed
     to

   - The clang build was broken by a BUILD_BUG_ON() we added.

   - The radix (Power9 only) version of map_kernel_page() was broken if
     our memory size was a multiple of 2MB, which it generally isn't

  Thanks to: Darren Stevens, Gavin Shan, Reza Arbab"

* tag 'powerpc-4.10-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/mm: Use the correct pointer when setting a 2MB pte
  powerpc: Fix build failure with clang due to BUILD_BUG_ON()
  powerpc: Revert the initial stack protector support
  powerpc/eeh: Fix wrong flag passed to eeh_unfreeze_pe()
  powerpc: Add missing error check to prom_find_boot_cpu()

Pull tracing fix from Steven Rostedt:
 "Simple fix of s/static struct __init/static __init struct/"

* tag 'trace-v4.10-rc2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing/kprobes: Fix __init annotation

Merge kcrctab entry fixes from Ard Biesheuvel:
 "This is a followup to [0] 'modversions: redefine kcrctab entries as
  relative CRC pointers', but since relative CRC pointers do not work in
  modules, and are actually only needed by powerpc with
  CONFIG_RELOCATABLE=y, I have made it a Kconfig selectable feature
  instead.

  First it introduces the MODULE_REL_CRCS Kconfig symbol, and adds the
  kbuild handling of it, i.e., modpost, genksyms and kallsyms.

  Then it switches all architectures to 32-bit CRC entries in kcrctab,
  where all architectures except powerpc with CONFIG_RELOCATABLE=y use
  absolute ELF symbol references as before"

[0] http://marc.info/?l=linux-arch&m=148493613415294&w=2

* emailed patches from Ard Biesheuvel:
  module: unify absolute krctab definitions for 32-bit and 64-bit
  modversions: treat symbol CRCs as 32 bit quantities
  kbuild: modversions: add infrastructure for emitting relative CRCs

The function order_base_2() is defined (according to the comment block)
as returning zero on input zero, but subsequently passes the input into
roundup_pow_of_two(), which is explicitly undefined for input zero.

This has gone unnoticed until now, but optimization passes in GCC 7 may
produce constant folded function instances where a constant value of
zero is passed into order_base_2(), resulting in link errors against the
deliberately undefined '____ilog2_NaN'.

So update order_base_2() to adhere to its own documented interface.

[ See

     http://marc.info/?l=linux-kernel&m=147672952517795&w=2

  and follow-up discussion for more background. The gcc "optimization
  pass" is really just broken, but now the GCC trunk problem seems to
  have escaped out of just specially built daily images, so we need to
  work around it in mainline.    - Linus ]
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Saving unsupported state prevents migration when the new host does not
support a XSAVE feature of the original host, even if the feature is not
exposed to the guest.

We've masked host features with guest-visible features before, with
4344ee98 ("KVM: x86: only copy XSAVE state for the supported
features") and dropped it when implementing XSAVES.  Do it again.

Fixes: df1daba7 ("KVM: x86: support XSAVES usage in the host")
Cc: stable@vger.kernel.org
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

The previous patch introduced a separate inline asm version of the
krcrctab declaration template for use with 64-bit architectures, which
cannot refer to ELF symbols using 32-bit quantities.

This declaration should be equivalent to the C one for 32-bit
architectures, but just in case - unify them in a separate patch, which
can simply be dropped if it turns out to break anything.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The modversion symbol CRCs are emitted as ELF symbols, which allows us
to easily populate the kcrctab sections by relying on the linker to
associate each kcrctab slot with the correct value.

This has a couple of downsides:

 - Given that the CRCs are treated as memory addresses, we waste 4 bytes
   for each CRC on 64 bit architectures,

 - On architectures that support runtime relocation, a R_<arch>_RELATIVE
   relocation entry is emitted for each CRC value, which identifies it
   as a quantity that requires fixing up based on the actual runtime
   load offset of the kernel. This results in corrupted CRCs unless we
   explicitly undo the fixup (and this is currently being handled in the
   core module code)

 - Such runtime relocation entries take up 24 bytes of __init space
   each, resulting in a x8 overhead in [uncompressed] kernel size for
   CRCs.

Switching to explicit 32 bit values on 64 bit architectures fixes most
of these issues, given that 32 bit values are not treated as quantities
that require fixing up based on the actual runtime load offset.  Note
that on some ELF64 architectures [such as PPC64], these 32-bit values
are still emitted as [absolute] runtime relocatable quantities, even if
the value resolves to a build time constant.  Since relative relocations
are always resolved at build time, this patch enables MODULE_REL_CRCS on
powerpc when CONFIG_RELOCATABLE=y, which turns the absolute CRC
references into relative references into .rodata where the actual CRC
value is stored.

So redefine all CRC fields and variables as u32, and redefine the
__CRC_SYMBOL() macro for 64 bit builds to emit the CRC reference using
inline assembler (which is necessary since 64-bit C code cannot use
32-bit types to hold memory addresses, even if they are ultimately
resolved using values that do not exceed 0xffffffff).  To avoid
potential problems with legacy 32-bit architectures using legacy
toolchains, the equivalent C definition of the kcrctab entry is retained
for 32-bit architectures.

Note that this mostly reverts commit d4703aef ("module: handle ppc64
relocating kcrctabs when CONFIG_RELOCATABLE=y")
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>