Add basic support for RZ/G2L SMARC EVK (based on R9A07G044L2):
- memory
- External input clock
- SCIF
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20210609153230.6967-12-prabhakar.mahadev-lad.rj@bp.renesas.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Add initial DTSI for RZ/G2{L,LC} SoC's.

File structure:
r9a07g044.dtsi  => RZ/G2L family SoC common parts
r9a07g044l1.dtsi => RZ/G2L R9A07G044L1 SoC specific parts
r9a07g044l2.dtsi => RZ/G2L R9A07G044L2 SoC specific parts
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20210609153230.6967-11-prabhakar.mahadev-lad.rj@bp.renesas.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Renesas RZ/G2L DT Binding Definitions

Clock definitions for the Renesas RZ/G2L (R9A07G044) SoC, shared by
driver and DT source files.

Define RZ/G2L (R9A07G044) Clock Pulse Generator Core Clock
and module clock outputs, as listed in Table 8.3 ("Clock List")
of the RZ/G2L Hardware User's Manual (Rev.0.42, Feb.2021).
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20210609153230.6967-7-prabhakar.mahadev-lad.rj@bp.renesas.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

"make dtbs_check":

    arm64/boot/dts/renesas/r8a779a0-falcon.dt.yaml: interrupt-controller@f1000000: 'power-domains' does not match any of the regexes: '^(msi-controller|gic-its|interrupt-controller)@[0-9a-f]+$', '^gic-its@', '^interrupt-controller@[0-9a-f]+$', 'pinctrl-[0-9]+'
	    From schema: Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.yaml

Remove the "power-domains" property, as the GIC on R-Car V3U is
always-on, and not part of a clock domain.

Fixes: 834c310f ("arm64: dts: renesas: Add Renesas R8A779A0 SoC support")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/a9ae5cbc7c586bf2c6b18ddc665ad7051bd1d206.1622560236.git.geert+renesas@glider.be

Populate the device node for the Interrupt Controller for External
Devices (INTC-EX) on R-Car M3-W+, which serves external IRQ pins
IRQ[0-5].
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/6f3cc1a1b6d777e743a7a9e66a80aaf9d5232a4f.1622547125.git.geert+renesas@glider.be

The GPIO pins connected to the 4 Software Switches ("SOFT_SW", SW12) do
not have external pull-up resistors, but rely on internal pull-ups being
enabled.  Fortunately this is satisfied by the initial state of these
pins.

Make this explicit by enabling bias-pull-up, to remove the dependency on
initial state and/or boot loader configuration.

While at it, rename the surrounding device node from "gpio-keys" to
"keyboard", to comply with generic node name recommendations.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/45f38a5333feba9bea80efeb5a41a6c3f60deda2.1619785905.git.geert+renesas@glider.be

The GPIO pins connected to the 4 Software Switches ("SOFT_SW", SW2) do
not have external pull-up resistors, but rely on internal pull-ups being
enabled.  Fortunately this is satisfied by the initial state of these
pins.

Make this explicit by enabling bias-pull-up, to remove the dependency on
initial state and/or boot loader configuration.

While at it, rename the surrounding device node from "gpio-keys" to
"keyboard", to comply with generic node name recommendations.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/1cdec892b1491309b12bdaf7bc8428b3a19b1ed5.1619785905.git.geert+renesas@glider.be

The GPIO pins connected to the 4 Software Switches (SW2) and the second
Tact Switch (SW25) do not have external pull-up resistors, but rely on
internal pull-ups being enabled.  Fortunately this is satisfied by the
initial state of these pins.

Make this explicit by enabling bias-pull-up, to remove the dependency on
initial state and/or boot loader configuration.

Note that the GPIO pin connected to the first Tact Switch (SW24) does
have an external pull-up resistor.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/011e4c461767f2dd690b655b3dd501eb554184c1.1619785905.git.geert+renesas@glider.be

The GPIO pins connected to the 4 Software Switches (SW2) do not have
external pull-up resistors, but rely on internal pull-ups being enabled.
Fortunately this is satisfied by the initial state of these pins.

Make this explicit by enabling bias-pull-up, to remove the dependency on
initial state and/or boot loader configuration.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/9fae3c0c2c0000f6b43c9ce87fe64a594b30a7da.1619785905.git.geert+renesas@glider.be

Correct the voltages in the "Power Optimized" (<= 1.5 GHz) Cortex-A57
operating point table entries for the R-Car M3-W and M3-W+ SoCs from
0.82V to 0.83V, as per the R-Car Gen3 EC Manual Errata for Revision
0.53.

Based on a patch for R-Car M3-W in the BSP by Takeshi Kihara
<takeshi.kihara.df@renesas.com>.

Fixes: da7e3113 ("arm64: dts: renesas: r8a7796: Add OPPs table for cpu devices")
Fixes: f51746ad ("arm64: dts: renesas: Add Renesas R8A77961 SoC support")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/b9e9db907514790574429b83d070c823b36085ef.1619699909.git.geert+renesas@glider.be

Tag the highest "Power Optimized" (1.5 GHz) Cortex-A57 operating point
table entries for the RZ/G2M, R-Car M3-W and M3-W+ SoCs with the
"opp-suspend" property.  This makes sure the system will enter suspend
in the same performance state as it will be resumed by the firmware
later, avoiding state inconsistencies after resume.

Based on a patch for R-Car M3-W in the BSP by Takeshi Kihara
<takeshi.kihara.df@renesas.com>.

Fixes: 800037e8 ("arm64: dts: renesas: r8a774a1: Add operating points")
Fixes: da7e3113 ("arm64: dts: renesas: r8a7796: Add OPPs table for cpu devices")
Fixes: f51746ad ("arm64: dts: renesas: Add Renesas R8A77961 SoC support")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Link: https://lore.kernel.org/r/45a061c3b0463aac7d10664f47c4afdd999da50d.1619699721.git.geert+renesas@glider.be

SW2 on Alt is connected as on Lager board. So, use the same GPIO
settings.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20210525091512.29119-1-wsa+renesas@sang-engineering.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

According to Documentation/devicetree/bindings/arm/cpus.yaml, the
"enable-method" property should be a property of the individual CPU
nodes, and not of the parent "cpus" container node.
However, on R-Car Gen2 and RZ/G1 SoCs, the property is tied to the
"cpus" node instead.

Secondary CPU bringup and CPU hot (un)plug work regardless, as
arm_dt_init_cpu_maps() falls back to looking in the "cpus" node.

The cpuidle code does not have such a fallback, so it does not detect
the enable-method.  Note that cpuidle does not support the
"renesas,apmu" enable-method yet, so for now this does not make any
difference.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/35fcfedf9de9269185c48ca5a6dfcba7cdd3484b.1621427319.git.geert+renesas@glider.be

The RZ/G2 boards expect there to be an external clock reference for
USB2 EHCI controllers.  For the Beacon boards, this reference clock
is controlled by a programmable versaclock.  Because the RZ/G2
family has a special clock driver when using an external clock,
the third clock reference in the EHCI node needs to point to this
special clock, called usb2_clksel.

Since the usb2_clksel does not keep the usb_extal clock enabled,
the 4th clock entry for the EHCI nodes needs to reference it to
keep the clock running and make USB functional.
Signed-off-by: Adam Ford <aford173@gmail.com>
Link: https://lore.kernel.org/r/20210513114617.30191-2-aford173@gmail.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

The USB extal clock reference isn't associated to a crystal, it's
associated to a programmable clock, so remove the extal reference,
add the usb2_clksel.  Since usb_extal is referenced by the versaclock,
reference it here so the usb2_clksel can get the proper clock speed
of 50MHz.
Signed-off-by: Adam Ford <aford173@gmail.com>
Link: https://lore.kernel.org/r/20210513114617.30191-1-aford173@gmail.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

According to the R-Car M1A and H1 Hardware User's Manuals Rev. 1.00, the
LSI internal delay for I2C instances 1 to 3 is 5 ns (typ.), which
differs from the default 50 ns as specified for instance 0.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/1eac63f15a776e492ff8a2d8447c5e1019982dd1.1620138979.git.geert+renesas@glider.be
Link: https://lore.kernel.org/r/73c96fd455df82ef04fd1db6d7dd79b4679f6c56.1620138979.git.geert+renesas@glider.be

This adds X1 clock which supplies a frequency of 148.5 MHz.
This clock is connected to the external dot clock input signal.
Signed-off-by: Valentine Barshak <valentine.barshak@cogentembedded.com>
[geert: Verified schematics]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Link: https://lore.kernel.org/r/75a66bae21937da1c69e8024ce61b35aad4ac9b8.1620119570.git.geert+renesas@glider.be

Rename "sw2_pins" and "sw2" to "keyboard_pins" resp. "keyboard", to
comply with generic name recommendations.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Link: https://lore.kernel.org/r/3d718cf69e21b1ceea0c29c0e841b9bdda44533d.1619785905.git.geert+renesas@glider.be

"make dtbs_check" complains:

    arch/arm/boot/dts/r8a7779-marzen.dt.yaml: display@fff80000: clock-names:0: 'du.0' was expected

Change the first clock name to match the DT bindings.
This has no effect on actual operation, as the Display Unit driver in
Linux does not use the first clock name on R-Car H1, but just grabs the
first clock.

Fixes: 665d79aa ("ARM: shmobile: marzen: Add DU external pixel clock to DT")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/9d5e1b371121883b3b3e10a3df43802a29c6a9da.1619699965.git.geert+renesas@glider.be

The V3MSK board has 2 GiB RAM according to the datasheet and schematics.
Signed-off-by: Valentine Barshak <valentine.barshak@cogentembedded.com>
[geert: Verified schematics]
Fixes: cc3e267e ("arm64: dts: renesas: initial V3MSK board device tree")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20210326121050.1578460-1-geert+renesas@glider.be

The eMMC card has two supplies, VCC and VCCQ. The VCC supplies the NAND
array and the VCCQ supplies the bus. On Condor, the VCC is connected to
3.3V rail, while the VCCQ is connected to 1.8V rail. Adjust the pinmux
to match the bus, which is always operating in 1.8V mode.

While at it, deduplicate the pinmux entries, which are now the same for
both default and UHS modes. We still need the two pinctrl entries to
match the bindings though.

Thanks to Marek Vasut for this description from commit 5f65328d
("arm64: dts: renesas: Switch eMMC bus to 1V8 on Salvator-X and ULCB").
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20210419143858.39401-1-wsa+renesas@sang-engineering.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

We need to configure their GPIOs to power on the MAX96712s.
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Link: https://lore.kernel.org/r/20210413181447.2588084-1-niklas.soderlund+renesas@ragnatech.seSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

The AVB reference clock assumes an external clock that runs
automatically.  Because the Versaclock is wired to provide the
AVB refclock, the device tree needs to reference it in order for the
driver to start the clock.
Signed-off-by: Adam Ford <aford173@gmail.com>
Link: https://lore.kernel.org/r/20210224115146.9131-5-aford173@gmail.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

The bindings have been updated to support two clocks.
Add a clock-names list in the device tree with fck in it.
Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20210224115146.9131-3-aford173@gmail.com
[geert: Update new r8a779a0.dtsi]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

The bindings have been updated to support two clocks.
Add a clock-names list in the device tree with fck in it.
Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20210224115146.9131-2-aford173@gmail.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Pull perf fixes from Thomas Gleixner:
 "Two perf fixes:

   - Do not check the LBR_TOS MSR when setting up unrelated LBR MSRs as
     this can cause malfunction when TOS is not supported

   - Allocate the LBR XSAVE buffers along with the DS buffers upfront
     because allocating them when adding an event can deadlock"

* tag 'perf-urgent-2021-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/lbr: Remove cpuc->lbr_xsave allocation from atomic context
  perf/x86: Avoid touching LBR_TOS MSR for Arch LBR

Pull locking fixes from Thomas Gleixner:
 "Two locking fixes:

   - Invoke the lockdep tracepoints in the correct place so the ordering
     is correct again

   - Don't leave the mutex WAITER bit stale when the last waiter is
     dropping out early due to a signal as that forces all subsequent
     lock operations needlessly into the slowpath until it's cleaned up
     again"

* tag 'locking-urgent-2021-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/mutex: clear MUTEX_FLAGS if wait_list is empty due to signal
  locking/lockdep: Correct calling tracepoints

Pull irq fixes from Thomas Gleixner:
 "A few fixes for irqchip drivers:

   - Allocate interrupt descriptors correctly on Mainstone PXA when
     SPARSE_IRQ is enabled; otherwise the interrupt association fails

   - Make the APPLE AIC chip driver depend on APPLE

   - Remove redundant error output on devm_ioremap_resource() failure"

* tag 'irq-urgent-2021-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip: Remove redundant error printing
  irqchip/apple-aic: APPLE_AIC should depend on ARCH_APPLE
  ARM: PXA: Fix cplds irqdesc allocation when using legacy mode

Pull x86 fixes from Borislav Petkov:

 - Fix how SEV handles MMIO accesses by forwarding potential page faults
   instead of killing the machine and by using the accessors with the
   exact functionality needed when accessing memory.

 - Fix a confusion with Clang LTO compiler switches passed to the it

 - Handle the case gracefully when VMGEXIT has been executed in
   userspace

* tag 'x86_urgent_for_v5.13_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/sev-es: Use __put_user()/__get_user() for data accesses
  x86/sev-es: Forward page-faults which happen during emulation
  x86/sev-es: Don't return NULL from sev_es_get_ghcb()
  x86/build: Fix location of '-plugin-opt=' flags
  x86/sev-es: Invalidate the GHCB after completing VMGEXIT
  x86/sev-es: Move sev_es_put_ghcb() in prep for follow on patch

Pull powerpc fixes from Michael Ellerman:

 - Fix breakage of strace (and other ptracers etc.) when using the new
   scv ABI (Power9 or later with glibc >= 2.33).

 - Fix early_ioremap() on 64-bit, which broke booting on some machines.

Thanks to Dmitry V. Levin, Nicholas Piggin, Alexey Kardashevskiy, and
Christophe Leroy.

* tag 'powerpc-5.13-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/64s/syscall: Fix ptrace syscall info with scv syscalls
  powerpc/64s/syscall: Use pt_regs.trap to distinguish syscall ABI difference between sc and scv syscalls
  powerpc: Fix early setup to make early_ioremap() work

Merge tag 'kbuild-fixes-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - Fix short log indentation for tools builds

 - Fix dummy-tools to adjust to the latest stackprotector check

* tag 'kbuild-fixes-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: dummy-tools: adjust to stricter stackprotector check
  scripts/jobserver-exec: Fix a typo ("envirnoment")
  tools build: Fix quiet cmd indentation

Merge misc fixes from Andrew Morton:
 "10 patches.

  Subsystems affected by this patch series: mm (pagealloc, gup, kasan,
  and userfaultfd), ipc, selftests, watchdog, bitmap, procfs, and lib"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  userfaultfd: hugetlbfs: fix new flag usage in error path
  lib: kunit: suppress a compilation warning of frame size
  proc: remove Alexey from MAINTAINERS
  linux/bits.h: fix compilation error with GENMASK
  watchdog: reliable handling of timestamps
  kasan: slab: always reset the tag in get_freepointer_safe()
  tools/testing/selftests/exec: fix link error
  ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry
  Revert "mm/gup: check page posion status for coredump."
  mm/shuffle: fix section mismatch warning

In commit d6995da3 ("hugetlb: use page.private for hugetlb specific
page flags") the use of PagePrivate to indicate a reservation count
should be restored at free time was changed to the hugetlb specific flag
HPageRestoreReserve.  Changes to a userfaultfd error path as well as a
VM_BUG_ON() in remove_inode_hugepages() were overlooked.

Users could see incorrect hugetlb reserve counts if they experience an
error with a UFFDIO_COPY operation.  Specifically, this would be the
result of an unlikely copy_huge_page_from_user error.  There is not an
increased chance of hitting the VM_BUG_ON.

Link: https://lkml.kernel.org/r/20210521233952.236434-1-mike.kravetz@oracle.com
Fixes: d6995da3 ("hugetlb: use page.private for hugetlb specific page flags")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Mina Almasry <almasry.mina@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/bitfield_kunit.c: In function `test_bitfields_constants':
lib/bitfield_kunit.c:93:1: warning: the frame size of 7456 bytes is larger than 2048 bytes [-Wframe-larger-than=]
 }
 ^

As the description of BITFIELD_KUNIT in lib/Kconfig.debug, it "Only useful
for kernel devs running the KUnit test harness, and not intended for
inclusion into a production build".  Therefore, it is not worth modifying
variable 'test_bitfields_constants' to clear this warning.  Just suppress
it.

Link: https://lkml.kernel.org/r/20210518094533.7652-1-thunder.leizhen@huawei.comSigned-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Vitor Massaru Iha <vitor@massaru.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

People Cc me and I don't have time.

Link: https://lkml.kernel.org/r/YKarMxHJBIhMHQIh@localhost.localdomainSigned-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

GENMASK() has an input check which uses __builtin_choose_expr() to
enable a compile time sanity check of its inputs if they are known at
compile time.

However, it turns out that __builtin_constant_p() does not always return
a compile time constant [0].  It was thought this problem was fixed with
gcc 4.9 [1], but apparently this is not the case [2].

Switch to use __is_constexpr() instead which always returns a compile time
constant, regardless of its inputs.

Link: https://lore.kernel.org/lkml/42b4342b-aefc-a16a-0d43-9f9c0d63ba7a@rasmusvillemoes.dk [0]
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=19449 [1]
Link: https://lore.kernel.org/lkml/1ac7bbc2-45d9-26ed-0b33-bf382b8d858b@I-love.SAKURA.ne.jp [2]
Link: https://lkml.kernel.org/r/20210511203716.117010-1-rikard.falkeborn@gmail.comSigned-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Yury Norov <yury.norov@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 9bf3bc94 ("watchdog: cleanup handling of false positives")
tried to handle a virtual host stopped by the host a more
straightforward and cleaner way.

But it introduced a risk of false softlockup reports.  The virtual host
might be stopped at any time, for example between
kvm_check_and_clear_guest_paused() and is_softlockup().  As a result,
is_softlockup() might read the updated jiffies and detects a softlockup.

A solution might be to put back kvm_check_and_clear_guest_paused() after
is_softlockup() and detect it.  But it would put back the cycle that
complicates the logic.

In fact, the handling of all the timestamps is not reliable.  The code
does not guarantee when and how many times the timestamps are read.  For
example, "period_ts" might be touched anytime also from NMI and re-read in
is_softlockup().  It works just by chance.

Fix all the problems by making the code even more explicit.

1. Make sure that "now" and "period_ts" timestamps are read only once.
   They might be changed at anytime by NMI or when the virtual guest is
   stopped by the host.  Note that "now" timestamp does this implicitly
   because "jiffies" is marked volatile.

2. "now" time must be read first.  The state of "period_ts" will
   decide whether it will be used or the period will get restarted.

3. kvm_check_and_clear_guest_paused() must be called before reading
   "period_ts".  It touches the variable when the guest was stopped.

As a result, "now" timestamp is used only when the watchdog was not
touched and the guest not stopped in the meantime.  "period_ts" is
restarted in all other situations.

Link: https://lkml.kernel.org/r/YKT55gw+RZfyoFf7@alley
Fixes: 9bf3bc94 ("watchdog: cleanup handling of false positives")
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reported-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

With CONFIG_DEBUG_PAGEALLOC enabled, the kernel should also untag the
object pointer, as done in get_freepointer().

Failing to do so reportedly leads to SLUB freelist corruptions that
manifest as boot-time crashes.

Link: https://lkml.kernel.org/r/20210514072228.534418-1-glider@google.comSigned-off-by: Alexander Potapenko <glider@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Elliot Berman <eberman@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>