This allows x86_64 kernels to enable vmapped stacks by setting
HAVE_ARCH_VMAP_STACK=y - which enables the CONFIG_VMAP_STACK=y
high level Kconfig option.

There are a couple of interesting bits:

First, x86 lazily faults in top-level paging entries for the vmalloc
area.  This won't work if we get a page fault while trying to access
the stack: the CPU will promote it to a double-fault and we'll die.
To avoid this problem, probe the new stack when switching stacks and
forcibly populate the pgd entry for the stack when switching mms.

Second, once we have guard pages around the stack, we'll want to
detect and handle stack overflow.

I didn't enable it on x86_32.  We'd need to rework the double-fault
code a bit and I'm concerned about running out of vmalloc virtual
addresses under some workloads.

This patch, by itself, will behave somewhat erratically when the
stack overflows while RSP is still more than a few tens of bytes
above the bottom of the stack.  Specifically, we'll get #PF and make
it to no_context and them oops without reliably triggering a
double-fault, and no_context doesn't know about stack overflows.
The next patch will improve that case.

Thank you to Nadav and Brian for helping me pay enough attention to
the SDM to hopefully get this right.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/c88f3e2920b18e6cc621d772a04a62c06869037e.1470907718.git.luto@kernel.org
[ Minor edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

If we're using CONFIG_VMAP_STACK=y and we manage to point an sg entry
at the stack, then either the sg page will be in highmem or sg_virt()
will return the direct-map alias.  In neither case will the existing
check_for_stack() implementation realize that it's a stack page.

Fix it by explicitly checking for stack pages.

This has no effect by itself.  It's broken out for ease of review.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/448460622731312298bf19dcbacb1606e75de7a9.1470907718.git.luto@kernel.org
[ Minor edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

If CONFIG_VMAP_STACK=y is selected, kernel stacks are allocated with
__vmalloc_node_range().

Grsecurity has had a similar feature (called GRKERNSEC_KSTACKOVERFLOW=y)
for a long time.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/14c07d4fd173a5b117f51e8b939f9f4323e39899.1470907718.git.luto@kernel.org
[ Minor edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Signed-off-by: Ingo Molnar <mingo@kernel.org>

The comment probably meant some old AMD64 incarnation which most likely
never saw the light of day. STAR and LSTAR are two different registers
and STAR sets CS/SS(DS) selectors for *all* modes, not only 32-bit.

So simply remove that comment.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160823172356.15879-1-bp@alien8.deSigned-off-by: Ingo Molnar <mingo@kernel.org>

Pull two parisc fixes from Helge Deller:
 "The first patch ensures that the high-res cr16 clocksource (which was
  added in kernel 4.7) gets choosen as default clocksource for parisc.

  The second patch moves the #define of EREFUSED down inside errno.h and
  thus unbreaks building the gccgo compiler"

* 'parisc-4.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Fix order of EREFUSED define in errno.h
  parisc: Fix automatic selection of cr16 clocksource

This is an entirely new driver instead of yet another set of patches
to sb_edac.c because:

1) Mapping from PCI devices to socket/memory controller is significantly
   different. Skylake scatters devices on a socket across a number of
   PCI buses.
2) There is an extra level of interleaving via the "mcroute" register
   that would be a little messy to squeeze into the old driver.
3) Validation is getting too expensive. Changes to sb_edac need to
   be checked against Sandy Bridge, Ivy Bridge, Haswell, Broadwell and
   Knights Landing.
Acked-by: Aristeu Rozanski <aris@redhat.com>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When building gccgo in userspace, errno.h gets parsed and the go include file
sysinfo.go is generated.

Since EREFUSED is defined to the same value as ECONNREFUSED, and ECONNREFUSED
is defined later on in errno.h, this leads to go complaining that EREFUSED
isn't defined yet.

Fix this trivial problem by moving the define of EREFUSED down after
ECONNREFUSED in errno.h (and clean up the indenting while touching this line).
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org

Commit 54b66800 (parisc: Add native high-resolution sched_clock()
implementation) added support to use the CPU-internal cr16 counters as reliable
clocksource with the help of HAVE_UNSTABLE_SCHED_CLOCK.

Sadly the commit missed to remove the hack which prevented cr16 to become the
default clocksource even on SMP systems.
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # 4.7+

The kernel test robot reported a usercopy failure in the new hardened
sanity checks, due to a page-crossing copy of the FPU state into the
task structure.

This happened because the kernel test robot was testing with SLOB, which
doesn't actually do the required book-keeping for slab allocations, and
as a result the hardening code didn't realize that the task struct
allocation was one single allocation - and the sanity checks fail.

Since SLOB doesn't even claim to support hardening (and you really
shouldn't use it), the straightforward solution is to just make the
usercopy hardening code depend on the allocator supporting it.
Reported-by: kernel test robot <xiaolong.ye@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull i2c fixes from Wolfram Sang:
 "I2C has some pretty standard driver bugfixes and one minor cleanup"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: meson: Use complete() instead of complete_all()
  i2c: brcmstb: Use complete() instead of complete_all()
  i2c: bcm-kona: Use complete() instead of complete_all()
  i2c: bcm-iproc: Use complete() instead of complete_all()
  i2c: at91: fix support of the "alternative command" feature
  i2c: ocores: add missed clk_disable_unprepare() on failure paths
  i2c: cros-ec-tunnel: Fix usage of cros_ec_cmd_xfer()
  i2c: mux: demux-pinctrl: properly roll back when adding adapter fails

Pull device mapper fixes from Mike Snitzer:

 - a stable fix for DM round robin multipath path selector to disable
   preemption before using this_cpu_ptr()

 - a slight increase in DM crypt's mempool reserves to make swap ontop
   of DM crypt more performant

 - a few DM raid fixes to issues found while testing changes that were
   merged in v4.8-rc1

* tag 'dm-4.8-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm raid: support raid0 with missing metadata devices
  dm raid: enhance attempt_restore_of_faulty_devices() to support more devices
  dm raid: fix restoring of failed devices regression
  dm raid: fix frozen recovery regression
  dm crypt: increase mempool reserve to better support swapping
  dm round robin: do not use this_cpu_ptr() without having preemption disabled

Pull SCSI fixes from James Bottomley:
 "Six fairly small fixes.  The ipr, mpt3sas and ses ones all trigger
  oopses.  The megaraid one fixes an attach failure on io mapped only
  cards, the fcoe one is an obvious problem in the error path and the
  aacraid one is a theoretical security issue (ability to trick the
  kernel into a buffer overrun)"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  ses: Fix racy cleanup of /sys in remove_dev()
  mpt3sas: Fix resume on WarpDrive flash cards
  ipr: Fix sync scsi scan
  megaraid_sas: Fix probing cards without io port
  aacraid: Check size values after double-fetch from user
  fcoe: Use kfree_skb() instead of kfree()

Pull USB fixes from Greg KH:
 "Here are a number of USB fixes for reported issues for your tree.

  The normal amount of gadget fixes, xhci fixes, new device ids, and a
  few other minor things.  All of them have been in linux-next for a
  while, the full details are in the shortlog below"

* tag 'usb-4.8-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (43 commits)
  xhci: don't dereference a xhci member after removing xhci
  usb: xhci: Fix panic if disconnect
  xhci: really enqueue zero length TRBs.
  xhci: always handle "Command Ring Stopped" events
  cdc-acm: fix wrong pipe type on rx interrupt xfers
  usb: misc: usbtest: add fix for driver hang
  usb: dwc3: gadget: stop processing on HWO set
  usb: dwc3: don't set last bit for ISOC endpoints
  usb: gadget: rndis: free response queue during REMOTE_NDIS_RESET_MSG
  usb: udc: core: fix error handling
  usb: gadget: fsl_qe_udc: off by one in setup_received_handle()
  usb/gadget: fix gadgetfs aio support.
  usb: gadget: composite: Fix return value in case of error
  usb: gadget: uvc: Fix return value in case of error
  usb: gadget: fix check in sync read from ep in gadgetfs
  usb: misc: usbtest: usbtest_do_ioctl may return positive integer
  usb: dwc3: fix missing platform_set_drvdata() in dwc3_of_simple_probe()
  usb: phy: omap-otg: Fix missing platform_set_drvdata() in omap_otg_probe()
  usb: gadget: configfs: add mutex lock before unregister gadget
  usb: gadget: u_ether: fix dereference after null check coverify warning
  ...

Merge tag 'xfs-iomap-for-linus-4.8-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs

Pull xfs and iomap fixes from Dave Chinner:
 "Changes in this update:

  Regression fixes for XFS changes introduce in 4.8-rc1:
   - buffer IO accounting assert failure
   - ENOSPC block accounting reservation issue
   - DAX IO path page cache invalidation fix
   - rmapbt on-disk block count in agf
   - correct classification of rmap block type when updating AGFL.
   - iomap support for attribute fork mapping

  Regression fixes for iomap infrastructure in 4.8-rc1:
   - fiemap: honor FIEMAP_FLAG_SYNC
   - fiemap: implement FIEMAP_FLAG_XATTR support to fix XFS regression
   - make mark_page_accessed and pagefault_disable usage consistent with
     other IO paths"

* tag 'xfs-iomap-for-linus-4.8-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs:
  xfs: remove OWN_AG rmap when allocating a block from the AGFL
  xfs: (re-)implement FIEMAP_FLAG_XATTR
  xfs: simplify xfs_file_iomap_begin
  iomap: mark ->iomap_end as optional
  iomap: prepare iomap_fiemap for attribute mappings
  iomap: fiemap should honor the FIEMAP_FLAG_SYNC flag
  iomap: remove superflous pagefault_disable from iomap_write_actor
  iomap: remove superflous mark_page_accessed from iomap_write_actor
  xfs: store rmapbt block count in the AGF
  xfs: don't invalidate whole file on DAX read/write
  xfs: fix bogus space reservation in xfs_iomap_write_allocate
  xfs: don't assert fail on non-async buffers on ioacct decrement

Merge tag 'hwmon-for-linus-v4.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

Pull hwmon fixes from Guenter Roeck:
 "Fix a bug in it87 driver and URLs in ftsteutates driver"

* tag 'hwmon-for-linus-v4.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: (ftsteutates) Correct ftp urls in driver documentation
  hwmon: (it87) Features mask must be 32 bit wide

Pull more drm fixes from Dave Airlie:
 "Daniel pointed out I'd missed some i915 fixes, and I also found a
  single etnaviv fix I missed.

  So here they are"

* tag 'drm-fixes-for-4.8-rc3-2' of git://people.freedesktop.org/~airlied/linux:
  drm/etnaviv: take GPU lock later in the submit process
  drm/i915: Fix modeset handling during gpu reset, v5.
  drm/i915: fix aliasing_ppgtt leak
  drm/i915: fix WaInsertDummyPushConstPs
  drm/i915: Fix iboost setting for SKL Y/U DP DDI buffer translation entry 2
  drm/i915/gen9: Give one extra block per line for SKL plane WM calculations
  drm/i915: Acquire audio powerwell for HD-Audio registers
  drm/i915: Add missing rpm wakelock to GGTT pread
  drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake
  drm/i915: Clean up the extra RPM ref on CHV with i915.enable_rc6=0
  drm/i915: Program iboost settings for HDMI/DVI on SKL
  drm/i915: Fix iboost setting for DDI with 4 lanes on SKL
  drm/i915: Handle ENOSPC after failing to insert a mappable node
  drm/i915: Flush GT idle status upon reset

Pull DeviceTree fixes from Rob Herring:

 - a couple of DT node ref counting fixes

 - fix __unflatten_device_tree for PPC PCI hotplug case

 - rework marking irq controllers as OF_POPULATED in cases where real
   driver is used.

 - disable of_platform_default_populate_init on PPC.  The change in
   initcall order causes problems which need to be sorted out later.

* tag 'devicetree-fixes-for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux:
  of: fix reference counting in of_graph_get_endpoint_by_regs
  of/platform: disable the of_platform_default_populate_init() for all the ppc boards
  ARM: imx6: mark GPC node as not populated after irq init to probe pm domain driver
  of/irq: Mark interrupt controllers as populated before initialisation
  drivers/of: Validate device node in __unflatten_device_tree()
  of: Delete an unnecessary check before the function call "of_node_put"

Pull documentation fixes from Jonathan Corbet:
 "Three small fixes for Sphinx-formatted documentation generation"

* tag '4.8-doc-fixes' of git://git.lwn.net/linux:
  doc-rst: customize RTD theme, drop padding of inline literal
  docs: kernel-documentation: remove some highlight directives
  docs: Set the Sphinx default highlight language to "guess"

Collection of i915 fixes.

* tag 'drm-intel-fixes-2016-08-15' of git://anongit.freedesktop.org/drm-intel:
  drm/i915: Fix modeset handling during gpu reset, v5.
  drm/i915: fix aliasing_ppgtt leak
  drm/i915: fix WaInsertDummyPushConstPs
  drm/i915: Fix iboost setting for SKL Y/U DP DDI buffer translation entry 2
  drm/i915/gen9: Give one extra block per line for SKL plane WM calculations
  drm/i915: Acquire audio powerwell for HD-Audio registers
  drm/i915: Add missing rpm wakelock to GGTT pread
  drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake
  drm/i915: Clean up the extra RPM ref on CHV with i915.enable_rc6=0
  drm/i915: Program iboost settings for HDMI/DVI on SKL
  drm/i915: Fix iboost setting for DDI with 4 lanes on SKL
  drm/i915: Handle ENOSPC after failing to insert a mappable node
  drm/i915: Flush GT idle status upon reset

Single GPU recovery fix
* 'drm-etnaviv-fixes' of git://git.pengutronix.de/git/lst/linux:
  drm/etnaviv: take GPU lock later in the submit process

Pull x86 fixes from Ingo Molnar:
 "An initrd microcode loading fix, and an SMP bootup topology setup fix
  to resolve crashes on SGI/UV systems if the BIOS is configured in a
  certain way"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/smp: Fix __max_logical_packages value setup
  x86/microcode/AMD: Fix initrd loading with CONFIG_RANDOMIZE_MEMORY=y

Pull timer fixes from Ingo Molnar:
 "Three clocksource driver fixes"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clocksource/drivers/mips-gic-timer: Make gic_clocksource_of_init() return int
  clocksource/drivers/kona: Fix get_counter() error handling
  clocksource/drivers/time-armada-370-xp: Fix the clock reference

Pull scheduler fixes from Ingo Molnar:
 "Two cputime fixes - hopefully the last ones"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/cputime: Resync steal time when guest & host lose sync
  sched/cputime: Fix NO_HZ_FULL getrusage() monotonicity regression

Pull perf fixes from Ingo Molnar:
 "Mostly tooling fixes, but also start/stop filter related fixes, a perf
  event read() fix, a fix uncovered by fuzzing, and an uprobes leak fix"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Check return value of the perf_event_read() IPI
  perf/core: Enable mapping of the stop filters
  perf/core: Update filters only on executable mmap
  perf/core: Fix file name handling for start/stop filters
  perf/core: Fix event_function_local()
  uprobes: Fix the memcg accounting
  perf intel-pt: Fix occasional decoding errors when tracing system-wide
  tools: Sync kvm related header files for arm64 and s390
  perf probe: Release resources on error when handling exit paths
  perf probe: Check for dup and fdopen failures
  perf symbols: Fix annotation of objects with debuginfo files
  perf script: Don't disable use_callchain if input is pipe
  perf script: Show proper message when failed list scripts
  perf jitdump: Add the right header to get the major()/minor() definitions
  perf ppc64le: Fix build failure when libelf is not present
  perf tools mem: Fix -t store option for record command
  perf intel-pt: Fix ip compression

Pull locking fixes from Ingo Molnar:
 "Two lockless_dereference() related fixes"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/barriers: Suppress sparse warnings in lockless_dereference()
  Revert "drm/fb-helper: Reduce READ_ONCE(master) to lockless_dereference"

Pull arm64 fixes from Catalin Marinas:

 - Avoid a literal load with the MMU off on the CPU resume path
   (potential inconsistency between cache and RAM)

 - Build error with CONFIG_ACPI=n fixed

 - Compiler warning in the arch/arm64/mm/dump.c code fixed

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: Fix shift warning in arch/arm64/mm/dump.c
  arm64: kernel: avoid literal load of virtual address with MMU off
  arm64: Fix NUMA build error when !CONFIG_ACPI

Pull ARM fixes from Russell King:
 "Only three fixes this time:

   - Emil found an overflow problem with the memory layout sanity check.

   - Ard Biesheuvel noticed that late-allocated page tables (for EFI)
     weren't being properly constructed.

   - Guenter Roeck reported a problem found on qemu caused by the recent
     addr_limit changes"

* 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: fix address limit restoration for undefined instructions
  ARM: 8591/1: mm: use fully constructed struct pages for EFI pgd allocations
  ARM: 8590/1: sanity_check_meminfo(): avoid overflow on vmalloc_limit

Pull power management fixes from Rafael Wysocki:
 "More hibernation-related material: one fix for a recent regression in
  the core, one small cleanup of the x86-64 resume code and a
  documentation update.

  Specifics:

   - Fix a hibernate core regression resulting from uncovering a latent
     bug in its implementation of memory bitmaps by a recent commit
     (James Morse).

   - Use __pa() to compute a physical address in the x86-64 code
     finalizing resume from hibernation (Rafael Wysocki).

   - Update power management documentation related to system sleep
     states to remove outdated information from it and to add a
     description of a recently introduced hibernation debug feature to
     it (Rafael Wysocki)"

* tag 'pm-4.8-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PM / hibernate: Fix rtree_next_node() to avoid walking off list ends
  x86/power/64: Use __pa() for physical address computation
  PM / sleep: Update some system sleep documentation

Pull drm fixes from Dave Airlie:
 "Pretty quiet so far:

   - a few amdgpu/radeon fixup for pcie pm changes
   - a couple of amdgpu fixes
   - some build fixes
   - printk fix"

* tag 'drm-fixes-for-4.8-rc3' of git://people.freedesktop.org/~airlied/linux:
  drm/amdgpu: Change GART offset to 64-bit
  drm/mediatek: add ARM_SMCCC dependency
  drm/mediatek: add CONFIG_OF dependency
  drm/mediatek: add COMMON_CLK dependency
  drm/amdgpu: Fix memory trashing if UVD ring test fails
  drm/amdgpu: fix vm init error path
  drm/amdkfd: print doorbell offset as a hex value
  Revert "drm/radeon: work around lack of upstream ACPI support for D3cold"
  Revert "drm/amdgpu: work around lack of upstream ACPI support for D3cold"

There has been a 64-byte gap at the end of the irq stack for at least 12
years.  It predates git history, and I can't find any good reason for
it.  Remove it.  What's the worst that could happen?
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/14f9281c5475cc44af95945ea7546bff2e3836db.1471535549.git.jpoimboe@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

When printing call return addresses found on a stack, /proc/<pid>/stack
can sometimes give a confusing result.  If the call instruction was the
last instruction in the function (which can happen when calling a
noreturn function), '%pS' will incorrectly display the name of the
function which happens to be next in the object code, rather than the
name of the actual calling function.

Use '%pB' instead, which was created for this exact purpose.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/47ad2821e5ebdbed1fbf83fb85424ae4fbdf8b6e.1471535549.git.jpoimboe@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

On x86_32, when an interrupt happens from kernel space, SS and SP aren't
pushed and the existing stack is used.  So pt_regs is effectively two
words shorter, and the previous stack pointer is normally the memory
after the shortened pt_regs, aka '&regs->sp'.

But in the rare case where the interrupt hits right after the stack
pointer has been changed to point to an empty stack, like for example
when call_on_stack() is used, the address immediately after the
shortened pt_regs is no longer on the stack.  In that case, instead of
'&regs->sp', the previous stack pointer should be retrieved from the
beginning of the current stack page.

kernel_stack_pointer() wants to do that, but it forgets to dereference
the pointer.  So instead of returning a pointer to the previous stack,
it returns a pointer to the beginning of the current stack.

Note that it's probably outside of kernel_stack_pointer()'s scope to be
switching stacks at all.  The x86_64 version of this function doesn't do
it, and it would be better for the caller to do it if necessary.  But
that's a patch for another day.  This just fixes the original intent.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 0788aa6a ("x86: Prepare removal of previous_esp from i386 thread_info structure")
Link: http://lkml.kernel.org/r/472453d6e9f6a2d4ab16aaed4935f43117111566.1471535549.git.jpoimboe@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

This zeroed word has no apparent purpose, so remove it.

Brian Gerst says:

  "FYI the word used to be the SS segment selector for the LSS
   instruction, which isn't needed in 64-bit mode."
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/b056855c295bbb3825b97c1e9f7958539a4d6cf2.1471535549.git.jpoimboe@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

When starting the dump of an exception stack, it shows "<<EOE>>" instead
of "<EOE>".  print_trace_stack() already adds brackets, no need to add
them again.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/77f185fd5b81845869b400aa619415458df6b6cc.1471535549.git.jpoimboe@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

The 'stack_start' variable is similar in usage to 'initial_code' and
'initial_gs': they're all stored in head_64.S and they're all updated by
SMP and ACPI suspend before starting a CPU.

Rename it to 'initial_stack' to be consistent with the others.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/87063d773a3212051b77e17b0ee427f6582a5050.1471535549.git.jpoimboe@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

There is no init_rsp variable.  Remove its extern.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/c183bbecd5730d84e8c6aff3824537c1c1bf3591.1471535549.git.jpoimboe@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

There are a bewildering array of options for dumping the stack.
Simplify things a little by removing show_trace(), which is unused.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/fe02292eac9d409001ec0cf6d06f90ced242570d.1471535549.git.jpoimboe@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

Signed-off-by: Ingo Molnar <mingo@kernel.org>