The only user of thread_saved_pc() in non-arch-specific code was removed
in commit 8243d5597793 ("sched/core: Remove pointless printout in
sched_show_task()").  Remove the implementations as well.

Some architectures use thread_saved_pc() in their arch-specific code.
Leave their thread_saved_pc() intact.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Stack guard page is a useful feature to reduce a risk of stack smashing
into a different mapping. We have been using a single page gap which
is sufficient to prevent having stack adjacent to a different mapping.
But this seems to be insufficient in the light of the stack usage in
userspace. E.g. glibc uses as large as 64kB alloca() in many commonly
used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX]
which is 256kB or stack strings with MAX_ARG_STRLEN.

This will become especially dangerous for suid binaries and the default
no limit for the stack size limit because those applications can be
tricked to consume a large portion of the stack and a single glibc call
could jump over the guard page. These attacks are not theoretical,
unfortunatelly.

Make those attacks less probable by increasing the stack guard gap
to 1MB (on systems with 4k pages; but make it depend on the page size
because systems with larger base pages might cap stack allocations in
the PAGE_SIZE units) which should cover larger alloca() and VLA stack
allocations. It is obviously not a full fix because the problem is
somehow inherent, but it should reduce attack space a lot.

One could argue that the gap size should be configurable from userspace,
but that can be done later when somebody finds that the new 1MB is wrong
for some special case applications.  For now, add a kernel command line
option (stack_guard_gap) to specify the stack gap size (in page units).

Implementation wise, first delete all the old code for stack guard page:
because although we could get away with accounting one extra page in a
stack vma, accounting a larger gap can break userspace - case in point,
a program run with "ulimit -S -v 20000" failed when the 1MB gap was
counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK
and strict non-overcommit mode.

Instead of keeping gap inside the stack vma, maintain the stack guard
gap as a gap between vmas: using vm_start_gap() in place of vm_start
(or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few
places which need to respect the gap - mainly arch_get_unmapped_area(),
and and the vma tree's subtree_gap support for that.

Original-patch-by: Oleg Nesterov <oleg@redhat.com>
Original-patch-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

This patch removes the need of subdir-y. Now all files/directories under
arch/<arch>/include/uapi/ are exported.

The only change for userland is the layout of the command 'make
headers_install_all': directories asm-<arch> are replaced by arch-<arch>/.
Those new directories contains all files/directories of the specified arch.

Note that only cris and tile have more directories than only asm:
 - arch-v[10|32] for cris;
 - arch for tile.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Regularly, when a new header is created in include/uapi/, the developer
forgets to add it in the corresponding Kbuild file. This error is usually
detected after the release is out.

In fact, all headers under uapi directories should be exported, thus it's
useless to have an exhaustive list.

After this patch, the following files, which were not exported, are now
exported (with make headers_install_all):
asm-arc/kvm_para.h
asm-arc/ucontext.h
asm-blackfin/shmparam.h
asm-blackfin/ucontext.h
asm-c6x/shmparam.h
asm-c6x/ucontext.h
asm-cris/kvm_para.h
asm-h8300/shmparam.h
asm-h8300/ucontext.h
asm-hexagon/shmparam.h
asm-m32r/kvm_para.h
asm-m68k/kvm_para.h
asm-m68k/shmparam.h
asm-metag/kvm_para.h
asm-metag/shmparam.h
asm-metag/ucontext.h
asm-mips/hwcap.h
asm-mips/reg.h
asm-mips/ucontext.h
asm-nios2/kvm_para.h
asm-nios2/ucontext.h
asm-openrisc/shmparam.h
asm-parisc/kvm_para.h
asm-powerpc/perf_regs.h
asm-sh/kvm_para.h
asm-sh/ucontext.h
asm-tile/shmparam.h
asm-unicore32/shmparam.h
asm-unicore32/ucontext.h
asm-x86/hwcap2.h
asm-xtensa/kvm_para.h
drm/armada_drm.h
drm/etnaviv_drm.h
drm/vgem_drm.h
linux/aspeed-lpc-ctrl.h
linux/auto_dev-ioctl.h
linux/bcache.h
linux/btrfs_tree.h
linux/can/vxcan.h
linux/cifs/cifs_mount.h
linux/coresight-stm.h
linux/cryptouser.h
linux/fsmap.h
linux/genwqe/genwqe_card.h
linux/hash_info.h
linux/kcm.h
linux/kcov.h
linux/kfd_ioctl.h
linux/lightnvm.h
linux/module.h
linux/nbd-netlink.h
linux/nilfs2_api.h
linux/nilfs2_ondisk.h
linux/nsfs.h
linux/pr.h
linux/qrtr.h
linux/rpmsg.h
linux/sched/types.h
linux/sed-opal.h
linux/smc.h
linux/smc_diag.h
linux/stm.h
linux/switchtec_ioctl.h
linux/vfio_ccw.h
linux/wil6210_uapi.h
rdma/bnxt_re-abi.h

Note that I have removed from this list the files which are generated in every
exported directories (like .install or .install.cmd).

Thanks to Julien Floret <julien.floret@6wind.com> for the tip to get all
subdirs with a pure makefile command.

For the record, note that exported files for asm directories are a mix of
files listed by:
 - include/uapi/asm-generic/Kbuild.asm;
 - arch/<arch>/include/uapi/asm/Kbuild;
 - arch/<arch>/include/asm/Kbuild.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Mark Salter <msalter@redhat.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Pull timer updates from Thomas Gleixner:
 "The timer departement delivers:

   - more year 2038 rework

   - a massive rework of the arm achitected timer

   - preparatory patches to allow NTP correction of clock event devices
     to avoid early expiry

   - the usual pile of fixes and enhancements all over the place"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (91 commits)
  timer/sysclt: Restrict timer migration sysctl values to 0 and 1
  arm64/arch_timer: Mark errata handlers as __maybe_unused
  Clocksource/mips-gic: Remove redundant non devicetree init
  MIPS/Malta: Probe gic-timer via devicetree
  clocksource: Use GENMASK_ULL in definition of CLOCKSOURCE_MASK
  acpi/arm64: Add SBSA Generic Watchdog support in GTDT driver
  clocksource: arm_arch_timer: add GTDT support for memory-mapped timer
  acpi/arm64: Add memory-mapped timer support in GTDT driver
  clocksource: arm_arch_timer: simplify ACPI support code.
  acpi/arm64: Add GTDT table parse driver
  clocksource: arm_arch_timer: split MMIO timer probing.
  clocksource: arm_arch_timer: add structs to describe MMIO timer
  clocksource: arm_arch_timer: move arch_timer_needs_of_probing into DT init call
  clocksource: arm_arch_timer: refactor arch_timer_needs_probing
  clocksource: arm_arch_timer: split dt-only rate handling
  x86/uv/time: Set ->min_delta_ticks and ->max_delta_ticks
  unicore32/time: Set ->min_delta_ticks and ->max_delta_ticks
  um/time: Set ->min_delta_ticks and ->max_delta_ticks
  tile/time: Set ->min_delta_ticks and ->max_delta_ticks
  score/time: Set ->min_delta_ticks and ->max_delta_ticks
  ...

Pull uaccess unification updates from Al Viro:
 "This is the uaccess unification pile. It's _not_ the end of uaccess
  work, but the next batch of that will go into the next cycle. This one
  mostly takes copy_from_user() and friends out of arch/* and gets the
  zero-padding behaviour in sync for all architectures.

  Dealing with the nocache/writethrough mess is for the next cycle;
  fortunately, that's x86-only. Same for cleanups in iov_iter.c (I am
  sold on access_ok() in there, BTW; just not in this pile), same for
  reducing __copy_... callsites, strn*... stuff, etc. - there will be a
  pile about as large as this one in the next merge window.

  This one sat in -next for weeks. -3KLoC"

* 'work.uaccess' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (96 commits)
  HAVE_ARCH_HARDENED_USERCOPY is unconditional now
  CONFIG_ARCH_HAS_RAW_COPY_USER is unconditional now
  m32r: switch to RAW_COPY_USER
  hexagon: switch to RAW_COPY_USER
  microblaze: switch to RAW_COPY_USER
  get rid of padding, switch to RAW_COPY_USER
  ia64: get rid of copy_in_user()
  ia64: sanitize __access_ok()
  ia64: get rid of 'segment' argument of __do_{get,put}_user()
  ia64: get rid of 'segment' argument of __{get,put}_user_check()
  ia64: add extable.h
  powerpc: get rid of zeroing, switch to RAW_COPY_USER
  esas2r: don't open-code memdup_user()
  alpha: fix stack smashing in old_adjtimex(2)
  don't open-code kernel_setsockopt()
  mips: switch to RAW_COPY_USER
  mips: get rid of tail-zeroing in primitives
  mips: make copy_from_user() zero tail explicitly
  mips: clean and reorder the forest of macros...
  mips: consolidate __invoke_... wrappers
  ...

Pull EDAC updates from Borislav Petkov:

 - an EDAC driver for Cavium ThunderX RAS IP (Sergey Temerkhanov)

 - removal of DRAM error reporting through PCI SERR NMI (Borislav
   Petkov)

 - misc small fixes (Jan Glauber, Thor Thayer)

* tag 'edac_for_4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp:
  EDAC, ghes: Do not enable it by default
  EDAC: Rename report status accessors
  EDAC: Delete edac_stub.c
  EDAC: Update Kconfig help text
  EDAC: Remove EDAC_MM_EDAC
  EDAC: Issue tracepoint only when it is defined
  ACPI/extlog: Add EDAC dependency
  EDAC: Move edac_op_state to edac_mc.c
  EDAC: Remove edac_err_assert
  EDAC: Get rid of edac_handlers
  x86/nmi, EDAC: Get rid of DRAM error reporting thru PCI SERR NMI
  EDAC, highbank: Align Makefile directives
  EDAC, thunderx: Remove unused code
  EDAC, thunderx: Change LMC index calculation
  EDAC, altera: Fix peripheral warnings for Cyclone5
  EDAC, thunderx: Fix L2C MCI interrupt disable
  EDAC, thunderx: Add Cavium ThunderX EDAC driver

all architectures converted

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>