When migrating an anonymous private page to a ZONE_DEVICE private page,
the source page->mapping and page->index fields are copied to the
destination ZONE_DEVICE struct page and the page_mapcount() is
increased.  This is so rmap_walk() can be used to unmap and migrate the
page back to system memory.

However, try_to_unmap_one() computes the subpage pointer from a swap pte
which computes an invalid page pointer and a kernel panic results such
as:

  BUG: unable to handle page fault for address: ffffea1fffffffc8

Currently, only single pages can be migrated to device private memory so
no subpage computation is needed and it can be set to "page".

[rcampbell@nvidia.com: add comment]
  Link: http://lkml.kernel.org/r/20190724232700.23327-4-rcampbell@nvidia.com
Link: http://lkml.kernel.org/r/20190719192955.30462-4-rcampbell@nvidia.com
Fixes: a5430dda ("mm/migrate: support un-addressable ZONE_DEVICE page in migration")
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When a ZONE_DEVICE private page is freed, the page->mapping field can be
set.  If this page is reused as an anonymous page, the previous value
can prevent the page from being inserted into the CPU's anon rmap table.
For example, when migrating a pte_none() page to device memory:

  migrate_vma(ops, vma, start, end, src, dst, private)
    migrate_vma_collect()
      src[] = MIGRATE_PFN_MIGRATE
    migrate_vma_prepare()
      /* no page to lock or isolate so OK */
    migrate_vma_unmap()
      /* no page to unmap so OK */
    ops->alloc_and_copy()
      /* driver allocates ZONE_DEVICE page for dst[] */
    migrate_vma_pages()
      migrate_vma_insert_page()
        page_add_new_anon_rmap()
          __page_set_anon_rmap()
            /* This check sees the page's stale mapping field */
            if (PageAnon(page))
              return
            /* page->mapping is not updated */

The result is that the migration appears to succeed but a subsequent CPU
fault will be unable to migrate the page back to system memory or worse.

Clear the page->mapping field when freeing the ZONE_DEVICE page so stale
pointer data doesn't affect future page use.

Link: http://lkml.kernel.org/r/20190719192955.30462-3-rcampbell@nvidia.com
Fixes: b7a52310 ("mm: don't clear ->mapping in hmm_devmem_free")
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Jan Kara <jack@suse.cz>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Patch series "mm/hmm: fixes for device private page migration", v3.

Testing the latest linux git tree turned up a few bugs with page
migration to and from ZONE_DEVICE private and anonymous pages.
Hopefully it clarifies how ZONE_DEVICE private struct page uses the same
mapping and index fields from the source anonymous page mapping.

This patch (of 3):

Struct page for ZONE_DEVICE private pages uses the page->mapping and and
page->index fields while the source anonymous pages are migrated to
device private memory.  This is so rmap_walk() can find the page when
migrating the ZONE_DEVICE private page back to system memory.
ZONE_DEVICE pmem backed fsdax pages also use the page->mapping and
page->index fields when files are mapped into a process address space.

Add comments to struct page and remove the unused "_zd_pad_1" field to
make this more clear.

Link: http://lkml.kernel.org/r/20190724232700.23327-2-rcampbell@nvidia.comSigned-off-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull dax fixes from Dan Williams:
 "A filesystem-dax and device-dax fix for v5.3.

  The filesystem-dax fix is tagged for stable as the implementation has
  been mistakenly throwing away all cow pages on any truncate or hole
  punch operation as part of the solution to coordinate device-dma vs
  truncate to dax pages.

  The device-dax change fixes up a regression this cycle from the
  introduction of a common 'internal per-cpu-ref' implementation.

  Summary:

   - Fix dax_layout_busy_page() to not discard private cow pages of
     fs/dax private mappings.

   - Update the memremap_pages core to properly cleanup on behalf of
     internal reference-count users like device-dax"

* tag 'dax-fixes-5.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  mm/memremap: Fix reuse of pgmap instances with internal references
  dax: dax_layout_busy_page() should not unmap cow pages

Pull NTB fix from Jon Mason:
 "Bug fix for NTB MSI kernel compile warning"

* tag 'ntb-5.3-bugfixes' of git://github.com/jonmason/ntb:
  NTB/msi: remove incorrect MODULE defines

Pull RISC-V updates from Paul Walmsley:
 "A few minor RISC-V updates for v5.3-rc4:

   - Remove __udivdi3() from the 32-bit Linux port, converting the only
     upstream user to use do_div(), per Linux policy

   - Convert the RISC-V standard clocksource away from per-cpu data
     structures, since only one is used by Linux, even on a multi-CPU
     system

   - A set of DT binding updates that remove an obsolete text binding in
     favor of a YAML binding, fix a bogus compatible string in the
     schema (thus fixing a "make dtbs_check" warning), and clarifies the
     future values expected in one of the RISC-V CPU properties"

* tag 'riscv/for-v5.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  dt-bindings: riscv: fix the schema compatible string for the HiFive Unleashed board
  dt-bindings: riscv: remove obsolete cpus.txt
  RISC-V: Remove udivdi3
  riscv: delay: use do_div() instead of __udivdi3()
  dt-bindings: Update the riscv,isa string description
  RISC-V: Remove per cpu clocksource

Pull x86 fixes from Thomas Gleixner:
 "A few fixes for x86:

   - Don't reset the carefully adjusted build flags for the purgatory
     and remove the unwanted flags instead. The 'reset all' approach led
     to build fails under certain circumstances.

   - Unbreak CLANG build of the purgatory by avoiding the builtin
     memcpy/memset implementations.

   - Address missing prototype warnings by including the proper header

   - Fix yet more fall-through issues"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/lib/cpu: Address missing prototypes warning
  x86/purgatory: Use CFLAGS_REMOVE rather than reset KBUILD_CFLAGS
  x86/purgatory: Do not use __builtin_memcpy and __builtin_memset
  x86: mtrr: cyrix: Mark expected switch fall-through
  x86/ptrace: Mark expected switch fall-through

Pull perf tooling fixes from Thomas Gleixner:
 "Perf tooling fixes all over the place:

   - Fix the selection of the main thread COMM in db-export

   - Fix the disassemmbly display for BPF in annotate

   - Fix cpumap mask setup in perf ftrace when only one CPU is present

   - Add the missing 'cpu_clk_unhalted.core' event

   - Fix CPU 0 bindings in NUMA benchmarks

   - Fix the module size calculations for s390

   - Handle the gap between kernel end and module start on s390
     correctly

   - Build and typo fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf pmu-events: Fix missing "cpu_clk_unhalted.core" event
  perf annotate: Fix s390 gap between kernel end and module start
  perf record: Fix module size on s390
  perf tools: Fix include paths in ui directory
  perf tools: Fix a typo in a variable name in the Documentation Makefile
  perf cpumap: Fix writing to illegal memory in handling cpumap mask
  perf ftrace: Fix failure to set cpumask when only one cpu is present
  perf db-export: Fix thread__exec_comm()
  perf annotate: Fix printing of unaugmented disassembled instructions from BPF
  perf bench numa: Fix cpu0 binding

Pull scheduler fixes from Thomas Gleixner:
 "Three fixlets for the scheduler:

   - Avoid double bandwidth accounting in the push & pull code

   - Use a sane FIFO priority for the Pressure Stall Information (PSI)
     thread.

   - Avoid permission checks when setting the scheduler params for the
     PSI thread"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/psi: Do not require setsched permission from the trigger creator
  sched/psi: Reduce psimon FIFO priority
  sched/deadline: Fix double accounting of rq/running bw in push & pull

Pull irq fix from Thomas Gleixner:
 "A small fix for the affinity spreading code.

  It failed to handle situations where a single vector was requested
  either due to only one CPU being available or vector exhaustion
  causing only a single interrupt to be granted.

  The fix is to simply remove the requirement in the affinity spreading
  code for more than one interrupt being available"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq/affinity: Create affinity mask for single vector

Pull objtool warning fix from Thomas Gleixner:
 "The recent objtool fixes/enhancements unearthed a unbalanced CLAC in
  the i915 driver.

  Chris asked me to pick the fix up and route it through"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  drm/i915: Remove redundant user_access_end() from __copy_from_user() error path

Pull gfs2 fix from Andreas Gruenbacher:
 "Fix incorrect lseek / fiemap results"

* tag 'gfs2-v5.3-rc3.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
  gfs2: gfs2_walk_metadata fix

A compilation -Wimplicit-fallthrough warning was enabled by commit
a035d552 ("Makefile: Globally enable fall-through warning")

Even though clang 10.0.0 does not currently support this warning without
a patch, clang currently does not support a value for this option.

  Link: https://bugs.llvm.org/show_bug.cgi?id=39382

The gcc default for this warning is 3 so removing the =3 has no effect
for gcc and enables the warning for patched versions of clang.

Also remove the =3 from an existing use in a parisc Makefile:
arch/parisc/math-emu/Makefile
Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-and-tested-by: Nathan Chancellor <natechancellor@gmail.com>
Cc: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull char/misc driver fixes Greg KH:
 "Here are some small char/misc driver fixes for 5.3-rc4.

  Two of these are for the habanalabs driver for issues found when
  running on a big-endian system (are they still alive?) The others are
  tiny fixes reported by people, and a MAINTAINERS update about the
  location of the fpga development tree.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'char-misc-5.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  coresight: Fix DEBUG_LOCKS_WARN_ON for uninitialized attribute
  MAINTAINERS: Move linux-fpga tree to new location
  nvmem: Use the same permissions for eeprom as for nvmem
  habanalabs: fix host memory polling in BE architecture
  habanalabs: fix F/W download in BE architecture

Pull driver core fixes from Greg KH:
 "Here are two small fixes for some driver core issues that have been
  reported. There is also a kernfs "fix" here, which was then reverted
  because it was found to cause problems in linux-next.

  The driver core fixes both resolve reported issues, one with gpioint
  stuff that showed up in 5.3-rc1, and the other finally (and hopefully)
  resolves a very long standing race when removing glue directories.
  It's nice to get that issue finally resolved and the developers
  involved should be applauded for the persistence it took to get this
  patch finally accepted.

  All of these have been in linux-next for a while with no reported
  issues. Well, the one reported issue, hence the revert :)"

* tag 'driver-core-5.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  Revert "kernfs: fix memleak in kernel_ops_readdir()"
  kernfs: fix memleak in kernel_ops_readdir()
  driver core: Fix use-after-free and double free on glue directory
  driver core: platform: return -ENXIO for missing GpioInt

Pull tty fix from Greg KH:
 "Here is a single tty kgdb fix for 5.3-rc4.

  It fixes an annoying log message that has caused kdb to become
  useless. It's another fallout from commit ddde3c18 ("vt: More
  locking checks") which tries to enforce locking checks more strictly
  in the tty layer, unfortunatly when kdb is stopped, there's no need
  for locks :)

  This patch has been linux-next for a while with no reported issues"

* tag 'tty-5.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  kgdboc: disable the console lock when in kgdb

Pull staging / IIO driver fixes from Greg KH:
 "Here are some small staging and IIO driver fixes for 5.3-rc4.

  Nothing major, just resolutions for a number of small reported issues,
  full details in the shortlog.

  All have been in linux-next for a while with no reported issues"

* tag 'staging-5.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  iio: adc: gyroadc: fix uninitialized return code
  docs: generic-counter.rst: fix broken references for ABI file
  staging: android: ion: Bail out upon SIGKILL when allocating memory.
  Staging: fbtft: Fix GPIO handling
  staging: unisys: visornic: Update the description of 'poll_for_irq()'
  staging: wilc1000: flush the workqueue before deinit the host
  staging: gasket: apex: fix copy-paste typo
  Staging: fbtft: Fix reset assertion when using gpio descriptor
  Staging: fbtft: Fix probing of gpio descriptor
  iio: imu: mpu6050: add missing available scan masks
  iio: cros_ec_accel_legacy: Fix incorrect channel setting
  IIO: Ingenic JZ47xx: Set clock divider on probe
  iio: adc: max9611: Fix misuse of GENMASK macro

Pull USB fixes from Greg KH:
 "Here are some small USB fixes for 5.3-rc4.

  The "biggest" one here is moving code from one file to another in
  order to fix a long-standing race condition with the creation of sysfs
  files for USB devices. Turns out that there are now userspace tools
  out there that are hitting this long-known bug, so it's time to fix
  them. Thankfully the tool-maker in this case fixed the issue :)

  The other patches in here are all fixes for reported issues. Now that
  syzbot knows how to fuzz USB drivers better, and is starting to now
  fuzz the userspace facing side of them at the same time, there will be
  more and more small fixes like these coming, which is a good thing.

  All of these have been in linux-next with no reported issues"

* tag 'usb-5.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: setup authorized_default attributes using usb_bus_notify
  usb: iowarrior: fix deadlock on disconnect
  Revert "USB: rio500: simplify locking"
  usb: usbfs: fix double-free of usb memory upon submiturb error
  usb: yurex: Fix use-after-free in yurex_delete
  usb: typec: tcpm: Ignore unsupported/unknown alternate mode requests
  xhci: Fix NULL pointer dereference at endpoint zero reset.
  usb: host: xhci-rcar: Fix timeout in xhci_suspend()
  usb: typec: ucsi: ccg: Fix uninitilized symbol error
  usb: typec: tcpm: remove tcpm dir if no children
  usb: typec: tcpm: free log buf memory when remove debug file
  usb: typec: tcpm: Add NULL check before dereferencing config

Pull pin control fixes from Linus Walleij:

 - Delay acquisition of regmaps in the Aspeed G5 driver.

 - Make a symbol static to reduce compiler noise.

* tag 'pinctrl-v5.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl:
  pinctrl: aspeed: Make aspeed_pinmux_ips static
  pinctrl: aspeed-g5: Delay acquisition of regmaps

Pull powerpc fix from Michael Ellerman:
 "Just one fix, a revert of a commit that was meant to be a minor
  improvement to some inline asm, but ended up having no real benefit
  with GCC and broke booting 32-bit machines when using Clang.

  Thanks to: Arnd Bergmann, Christophe Leroy, Nathan Chancellor, Nick
  Desaulniers, Segher Boessenkool"

* tag 'powerpc-5.3-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  Revert "powerpc: slightly improve cache helpers"

Merge tag 'Wimplicit-fallthrough-5.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux

Pull fall-through fixes from Gustavo A. R. Silva:
 "Mark more switch cases where we are expecting to fall through, fixing
  fall-through warnings in arm, sparc64, mips, i386 and s390"

* tag 'Wimplicit-fallthrough-5.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux:
  ARM: ep93xx: Mark expected switch fall-through
  scsi: fas216: Mark expected switch fall-throughs
  pcmcia: db1xxx_ss: Mark expected switch fall-throughs
  video: fbdev: omapfb_main: Mark expected switch fall-throughs
  watchdog: riowd: Mark expected switch fall-through
  s390/net: Mark expected switch fall-throughs
  crypto: ux500/crypt: Mark expected switch fall-throughs
  watchdog: wdt977: Mark expected switch fall-through
  watchdog: scx200_wdt: Mark expected switch fall-through
  watchdog: Mark expected switch fall-throughs
  ARM: signal: Mark expected switch fall-through
  mfd: omap-usb-host: Mark expected switch fall-throughs
  mfd: db8500-prcmu: Mark expected switch fall-throughs
  ARM: OMAP: dma: Mark expected switch fall-throughs
  ARM: alignment: Mark expected switch fall-throughs
  ARM: tegra: Mark expected switch fall-through
  ARM/hw_breakpoint: Mark expected switch fall-throughs

Merge tag 'kbuild-fixes-v5.3-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - revive single target %.ko

 - do not create built-in.a where it is unneeded

 - do not create modules.order where it is unneeded

 - show a warning if subdir-y/m is used to visit a module Makefile

* tag 'kbuild-fixes-v5.3-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: show hint if subdir-y/m is used to visit module Makefile
  kbuild: generate modules.order only in directories visited by obj-y/m
  kbuild: fix false-positive need-builtin calculation
  kbuild: revive single target %.ko

Mark switch cases where we are expecting to fall through.

Fix the following warnings (Building: arm-ep93xx_defconfig arm):

arch/arm/mach-ep93xx/crunch.c: In function 'crunch_do':
arch/arm/mach-ep93xx/crunch.c:46:3: warning: this statement may
fall through [-Wimplicit-fallthrough=]
      memset(crunch_state, 0, sizeof(*crunch_state));
      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/arm/mach-ep93xx/crunch.c:53:2: note: here
     case THREAD_NOTIFY_EXIT:
     ^~~~

Notice that, in this particular case, the code comment is
modified in accordance with what GCC is expecting to find.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Mark switch cases where we are expecting to fall through.

Fix the following warnings (Building: rpc_defconfig arm):

drivers/scsi/arm/fas216.c: In function ‘fas216_disconnect_intr’:
drivers/scsi/arm/fas216.c:913:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (fas216_get_last_msg(info, info->scsi.msgin_fifo) == ABORT) {
      ^
drivers/scsi/arm/fas216.c:919:2: note: here
  default:    /* huh?     */
  ^~~~~~~
drivers/scsi/arm/fas216.c: In function ‘fas216_kick’:
drivers/scsi/arm/fas216.c:1959:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
   fas216_allocate_tag(info, SCpnt);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/arm/fas216.c:1960:2: note: here
  case TYPE_OTHER:
  ^~~~
drivers/scsi/arm/fas216.c: In function ‘fas216_busservice_intr’:
drivers/scsi/arm/fas216.c:1413:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
   fas216_stoptransfer(info);
   ^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/arm/fas216.c:1414:2: note: here
  case STATE(STAT_STATUS, PHASE_SELSTEPS):/* Sel w/ steps -> Status       */
  ^~~~
drivers/scsi/arm/fas216.c:1424:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
   fas216_stoptransfer(info);
   ^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/arm/fas216.c:1425:2: note: here
  case STATE(STAT_MESGIN, PHASE_COMMAND): /* Command -> Message In */
  ^~~~
drivers/scsi/arm/fas216.c: In function ‘fas216_funcdone_intr’:
drivers/scsi/arm/fas216.c:1573:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if ((stat & STAT_BUSMASK) == STAT_MESGIN) {
      ^
drivers/scsi/arm/fas216.c:1579:2: note: here
  default:
  ^~~~~~~
drivers/scsi/arm/fas216.c: In function ‘fas216_handlesync’:
drivers/scsi/arm/fas216.c:605:20: warning: this statement may fall through [-Wimplicit-fallthrough=]
   info->scsi.phase = PHASE_MSGOUT_EXPECT;
   ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~
drivers/scsi/arm/fas216.c:607:2: note: here
  case async:
  ^~~~
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Mark switch cases where we are expecting to fall through.

This patch fixes the following warnings (Building: db1xxx_defconfig mips):

drivers/pcmcia/db1xxx_ss.c:257:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/pcmcia/db1xxx_ss.c:269:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Mark switch cases where we are expecting to fall through.

This patch fixes the following warning (Building: omap1_defconfig arm):

drivers/watchdog/wdt285.c:170:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/watchdog/ar7_wdt.c:237:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/video/fbdev/omap/omapfb_main.c:449:23: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/video/fbdev/omap/omapfb_main.c:1549:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/video/fbdev/omap/omapfb_main.c:1547:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/video/fbdev/omap/omapfb_main.c:1545:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/video/fbdev/omap/omapfb_main.c:1543:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/video/fbdev/omap/omapfb_main.c:1540:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/video/fbdev/omap/omapfb_main.c:1538:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
drivers/video/fbdev/omap/omapfb_main.c:1535:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Mark switch cases where we are expecting to fall through.

This patch fixes the following warnings (Building: sparc64):

drivers/watchdog/riowd.c: In function ‘riowd_ioctl’:
drivers/watchdog/riowd.c:136:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
   riowd_writereg(p, riowd_timeout, WDTO_INDEX);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/watchdog/riowd.c:139:2: note: here
  case WDIOC_GETTIMEOUT:
  ^~~~
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Mark switch cases where we are expecting to fall through.

This patch fixes the following warnings (Building: s390):

drivers/s390/net/ctcm_fsms.c: In function ‘ctcmpc_chx_attnbusy’:
drivers/s390/net/ctcm_fsms.c:1703:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (grp->changed_side == 1) {
      ^
drivers/s390/net/ctcm_fsms.c:1707:2: note: here
  case MPCG_STATE_XID0IOWAIX:
  ^~~~

drivers/s390/net/ctcm_mpc.c: In function ‘ctc_mpc_alloc_channel’:
drivers/s390/net/ctcm_mpc.c:358:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (callback)
      ^
drivers/s390/net/ctcm_mpc.c:360:2: note: here
  case MPCG_STATE_XID0IOWAIT:
  ^~~~

drivers/s390/net/ctcm_mpc.c: In function ‘mpc_action_timeout’:
drivers/s390/net/ctcm_mpc.c:1469:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if ((fsm_getstate(rch->fsm) == CH_XID0_PENDING) &&
      ^
drivers/s390/net/ctcm_mpc.c:1472:2: note: here
  default:
  ^~~~~~~
drivers/s390/net/ctcm_mpc.c: In function ‘mpc_send_qllc_discontact’:
drivers/s390/net/ctcm_mpc.c:2087:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (grp->estconnfunc) {
      ^
drivers/s390/net/ctcm_mpc.c:2092:2: note: here
  case MPCG_STATE_FLOWC:
  ^~~~

drivers/s390/net/qeth_l2_main.c: In function ‘qeth_l2_process_inbound_buffer’:
drivers/s390/net/qeth_l2_main.c:328:7: warning: this statement may fall through [-Wimplicit-fallthrough=]
    if (IS_OSN(card)) {
       ^
drivers/s390/net/qeth_l2_main.c:337:3: note: here
   default:
   ^~~~~~~
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Mark switch cases where we are expecting to fall through.

This patch fixes the following warning (Building: arm):

drivers/crypto/ux500/cryp/cryp.c: In function ‘cryp_save_device_context’:
drivers/crypto/ux500/cryp/cryp.c:316:16: warning: this statement may fall through [-Wimplicit-fallthrough=]
   ctx->key_4_r = readl_relaxed(&src_reg->key_4_r);
drivers/crypto/ux500/cryp/cryp.c:318:2: note: here
  case CRYP_KEY_SIZE_192:
  ^~~~
drivers/crypto/ux500/cryp/cryp.c:320:16: warning: this statement may fall through [-Wimplicit-fallthrough=]
   ctx->key_3_r = readl_relaxed(&src_reg->key_3_r);
drivers/crypto/ux500/cryp/cryp.c:322:2: note: here
  case CRYP_KEY_SIZE_128:
  ^~~~
drivers/crypto/ux500/cryp/cryp.c:324:16: warning: this statement may fall through [-Wimplicit-fallthrough=]
   ctx->key_2_r = readl_relaxed(&src_reg->key_2_r);
drivers/crypto/ux500/cryp/cryp.c:326:2: note: here
  default:
  ^~~~~~~
In file included from ./include/linux/io.h:13:0,
                 from drivers/crypto/ux500/cryp/cryp_p.h:14,
                 from drivers/crypto/ux500/cryp/cryp.c:15:
drivers/crypto/ux500/cryp/cryp.c: In function ‘cryp_restore_device_context’:
./arch/arm/include/asm/io.h:92:22: warning: this statement may fall through [-Wimplicit-fallthrough=]
 #define __raw_writel __raw_writel
                      ^
./arch/arm/include/asm/io.h:299:29: note: in expansion of macro ‘__raw_writel’
 #define writel_relaxed(v,c) __raw_writel((__force u32) cpu_to_le32(v),c)
                             ^~~~~~~~~~~~
drivers/crypto/ux500/cryp/cryp.c:363:3: note: in expansion of macro ‘writel_relaxed’
   writel_relaxed(ctx->key_4_r, &reg->key_4_r);
   ^~~~~~~~~~~~~~
drivers/crypto/ux500/cryp/cryp.c:365:2: note: here
  case CRYP_KEY_SIZE_192:
  ^~~~
In file included from ./include/linux/io.h:13:0,
                 from drivers/crypto/ux500/cryp/cryp_p.h:14,
                 from drivers/crypto/ux500/cryp/cryp.c:15:
./arch/arm/include/asm/io.h:92:22: warning: this statement may fall through [-Wimplicit-fallthrough=]
 #define __raw_writel __raw_writel
                      ^
./arch/arm/include/asm/io.h:299:29: note: in expansion of macro ‘__raw_writel’
 #define writel_relaxed(v,c) __raw_writel((__force u32) cpu_to_le32(v),c)
                             ^~~~~~~~~~~~
drivers/crypto/ux500/cryp/cryp.c:367:3: note: in expansion of macro ‘writel_relaxed’
   writel_relaxed(ctx->key_3_r, &reg->key_3_r);
   ^~~~~~~~~~~~~~
drivers/crypto/ux500/cryp/cryp.c:369:2: note: here
  case CRYP_KEY_SIZE_128:
  ^~~~
In file included from ./include/linux/io.h:13:0,
                 from drivers/crypto/ux500/cryp/cryp_p.h:14,
                 from drivers/crypto/ux500/cryp/cryp.c:15:
./arch/arm/include/asm/io.h:92:22: warning: this statement may fall through [-Wimplicit-fallthrough=]
 #define __raw_writel __raw_writel
                      ^
./arch/arm/include/asm/io.h:299:29: note: in expansion of macro ‘__raw_writel’
 #define writel_relaxed(v,c) __raw_writel((__force u32) cpu_to_le32(v),c)
                             ^~~~~~~~~~~~
drivers/crypto/ux500/cryp/cryp.c:371:3: note: in expansion of macro ‘writel_relaxed’
   writel_relaxed(ctx->key_2_r, &reg->key_2_r);
   ^~~~~~~~~~~~~~
drivers/crypto/ux500/cryp/cryp.c:373:2: note: here
  default:
  ^~~~~~~
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Mark switch cases where we are expecting to fall through.

This patch fixes the following warning (Building: arm):

drivers/watchdog/wdt977.c: In function ‘wdt977_ioctl’:
  LD [M]  drivers/media/platform/vicodec/vicodec.o
drivers/watchdog/wdt977.c:400:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
   wdt977_keepalive();
   ^~~~~~~~~~~~~~~~~~
drivers/watchdog/wdt977.c:403:2: note: here
  case WDIOC_GETTIMEOUT:
  ^~~~
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Mark switch cases where we are expecting to fall through.

This patch fixes the following warning (Building: i386):

drivers/watchdog/scx200_wdt.c: In function ‘scx200_wdt_ioctl’:
drivers/watchdog/scx200_wdt.c:188:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
   scx200_wdt_ping();
   ^~~~~~~~~~~~~~~~~
drivers/watchdog/scx200_wdt.c:189:2: note: here
  case WDIOC_GETTIMEOUT:
  ^~~~
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Mark switch cases where we are expecting to fall through.

This patch fixes the following warnings:

drivers/watchdog/ar7_wdt.c: warning: this statement may fall
through [-Wimplicit-fallthrough=]:  => 237:3
drivers/watchdog/pcwd.c: warning: this statement may fall
through [-Wimplicit-fallthrough=]:  => 653:3
drivers/watchdog/sb_wdog.c: warning: this statement may fall
through [-Wimplicit-fallthrough=]:  => 204:3
drivers/watchdog/wdt.c: warning: this statement may fall
through [-Wimplicit-fallthrough=]:  => 391:3
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Mark switch cases where we are expecting to fall through.

This patch fixes the following warning:

arch/arm/kernel/signal.c: In function 'do_signal':
arch/arm/kernel/signal.c:598:12: warning: this statement may fall through [-Wimplicit-fallthrough=]
    restart -= 2;
    ~~~~~~~~^~~~
arch/arm/kernel/signal.c:599:3: note: here
   case -ERESTARTNOHAND:
   ^~~~
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Mark switch cases where we are expecting to fall through.

This patch fixes the following warnings:

drivers/mfd/omap-usb-host.c: In function 'usbhs_runtime_resume':
drivers/mfd/omap-usb-host.c:303:7: warning: this statement may fall through [-Wimplicit-fallthrough=]
    if (!IS_ERR(omap->hsic480m_clk[i])) {
       ^
drivers/mfd/omap-usb-host.c:313:3: note: here
   case OMAP_EHCI_PORT_MODE_TLL:
   ^~~~
drivers/mfd/omap-usb-host.c: In function 'usbhs_runtime_suspend':
drivers/mfd/omap-usb-host.c:345:7: warning: this statement may fall through [-Wimplicit-fallthrough=]
    if (!IS_ERR(omap->hsic480m_clk[i]))
       ^
drivers/mfd/omap-usb-host.c:349:3: note: here
   case OMAP_EHCI_PORT_MODE_TLL:
   ^~~~
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Mark switch cases where we are expecting to fall through.

This patch fixes the following warnings:

drivers/mfd/db8500-prcmu.c: In function 'dsiclk_rate':
drivers/mfd/db8500-prcmu.c:1592:7: warning: this statement may fall through [-Wimplicit-fallthrough=]
   div *= 2;
   ~~~~^~~~
drivers/mfd/db8500-prcmu.c:1593:2: note: here
  case PRCM_DSI_PLLOUT_SEL_PHI_2:
  ^~~~
drivers/mfd/db8500-prcmu.c:1594:7: warning: this statement may fall through [-Wimplicit-fallthrough=]
   div *= 2;
   ~~~~^~~~
drivers/mfd/db8500-prcmu.c:1595:2: note: here
  case PRCM_DSI_PLLOUT_SEL_PHI:
  ^~~~
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Mark switch cases where we are expecting to fall through.

This patch fixes the following warnings:

arch/arm/plat-omap/dma.c: In function 'omap_set_dma_src_burst_mode':
arch/arm/plat-omap/dma.c:384:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (dma_omap2plus()) {
      ^
arch/arm/plat-omap/dma.c:393:2: note: here
  case OMAP_DMA_DATA_BURST_16:
  ^~~~
arch/arm/plat-omap/dma.c:394:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (dma_omap2plus()) {
      ^
arch/arm/plat-omap/dma.c:402:2: note: here
  default:
  ^~~~~~~
arch/arm/plat-omap/dma.c: In function 'omap_set_dma_dest_burst_mode':
arch/arm/plat-omap/dma.c:473:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (dma_omap2plus()) {
      ^
arch/arm/plat-omap/dma.c:481:2: note: here
  default:
  ^~~~~~~

Notice that, in this particular case, the code comment is
modified in accordance with what GCC is expecting to find.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Mark switch cases where we are expecting to fall through.

This patch fixes the following warnings:

arch/arm/mm/alignment.c: In function 'thumb2arm':
arch/arm/mm/alignment.c:688:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if ((tinstr & (3 << 9)) == 0x0400) {
      ^
arch/arm/mm/alignment.c:700:2: note: here
  default:
  ^~~~~~~
arch/arm/mm/alignment.c: In function 'do_alignment_t32_to_handler':
arch/arm/mm/alignment.c:753:15: warning: this statement may fall through [-Wimplicit-fallthrough=]
   poffset->un = (tinst2 & 0xff) << 2;
   ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
arch/arm/mm/alignment.c:754:2: note: here
  case 0xe940:
  ^~~~
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Mark switch cases where we are expecting to fall through.

This patch fixes the following warning:

arch/arm/mach-tegra/reset.c: In function 'tegra_cpu_reset_handler_enable':
arch/arm/mach-tegra/reset.c:72:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
   tegra_cpu_reset_handler_set(reset_address);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/arm/mach-tegra/reset.c:74:2: note: here
  case 0:
  ^~~~
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Mark switch cases where we are expecting to fall through.

This patch fixes the following warnings:

arch/arm/kernel/hw_breakpoint.c: In function 'hw_breakpoint_arch_parse':
arch/arm/kernel/hw_breakpoint.c:609:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (hw->ctrl.len == ARM_BREAKPOINT_LEN_2)
      ^
arch/arm/kernel/hw_breakpoint.c:611:2: note: here
  case 3:
  ^~~~
arch/arm/kernel/hw_breakpoint.c:613:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (hw->ctrl.len == ARM_BREAKPOINT_LEN_1)
      ^
arch/arm/kernel/hw_breakpoint.c:615:2: note: here
  default:
  ^~~~~~~
arch/arm/kernel/hw_breakpoint.c: In function 'arch_build_bp_info':
arch/arm/kernel/hw_breakpoint.c:544:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if ((hw->ctrl.type != ARM_BREAKPOINT_EXECUTE)
      ^
arch/arm/kernel/hw_breakpoint.c:547:2: note: here
  default:
  ^~~~~~~
In file included from include/linux/kernel.h:11,
                 from include/linux/list.h:9,
                 from include/linux/preempt.h:11,
                 from include/linux/hardirq.h:5,
                 from arch/arm/kernel/hw_breakpoint.c:16:
arch/arm/kernel/hw_breakpoint.c: In function 'hw_breakpoint_pending':
include/linux/compiler.h:78:22: warning: this statement may fall through [-Wimplicit-fallthrough=]
 # define unlikely(x) __builtin_expect(!!(x), 0)
                      ^~~~~~~~~~~~~~~~~~~~~~~~~~
include/asm-generic/bug.h:136:2: note: in expansion of macro 'unlikely'
  unlikely(__ret_warn_on);     \
  ^~~~~~~~
arch/arm/kernel/hw_breakpoint.c:863:3: note: in expansion of macro 'WARN'
   WARN(1, "Asynchronous watchpoint exception taken. Debugging results may be unreliable\n");
   ^~~~
arch/arm/kernel/hw_breakpoint.c:864:2: note: here
  case ARM_ENTRY_SYNC_WATCHPOINT:
  ^~~~
arch/arm/kernel/hw_breakpoint.c: In function 'core_has_os_save_restore':
arch/arm/kernel/hw_breakpoint.c:910:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (oslsr & ARM_OSLSR_OSLM0)
      ^
arch/arm/kernel/hw_breakpoint.c:912:2: note: here
  default:
  ^~~~~~~
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>