Currently console_flush_on_panic() will attempt to acquire the
console lock when flushing the buffer on panic. If it fails to
acquire the lock, it continues anyway because this is the last
chance to get any pending records printed.

The reason why the console lock was attempted at all was to
prevent any other CPUs from acquiring the console lock for
printing while the panic CPU was printing. But as of the
previous commit, non-panic CPUs will no longer attempt to
acquire the console lock in a panic situation. Therefore it is
no longer strictly necessary for a panic CPU to acquire the
console lock.

Avoiding taking the console lock when flushing in panic has
the additional benefit of avoiding possible deadlocks due to
semaphore usage in NMI context (semaphores are not NMI-safe)
and avoiding possible deadlocks if another CPU accesses the
semaphore and is stopped while holding one of the semaphore's
internal spinlocks.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20230717194607.145135-5-john.ogness@linutronix.de

When in a panic situation, non-panic CPUs should avoid holding the
console lock so as not to contend with the panic CPU. This is already
implemented with abandon_console_lock_in_panic(), which is checked
after each printed line. However, non-panic CPUs should also avoid
trying to acquire the console lock during a panic.

Modify console_trylock() to fail and console_lock() to block() when
called from a non-panic CPU during a panic.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20230717194607.145135-4-john.ogness@linutronix.de

A semaphore is not NMI-safe, even when using down_trylock(). Both
down_trylock() and up() are using internal spinlocks and up()
might even call wake_up_process().

In the panic() code path it gets even worse because the internal
spinlocks of the semaphore may have been taken by a CPU that has
been stopped.

To reduce the risk of deadlocks caused by the console semaphore in
the panic path, make the following changes:

- First check if any consoles have implemented the unblank()
  callback. If not, then there is no reason to take the console
  semaphore anyway. (This check is also useful for the non-panic
  path since the locking/unlocking of the console lock can be
  quite expensive due to console printing.)

- If the panic path is in NMI context, bail out without attempting
  to take the console semaphore or calling any unblank() callbacks.
  Bailing out is acceptable because console_unblank() would already
  bail out if the console semaphore is contended. The alternative of
  ignoring the console semaphore and calling the unblank() callbacks
  anyway is a bad idea because these callbacks are also not NMI-safe.

If consoles with unblank() callbacks exist and console_unblank() is
called from a non-NMI panic context, it will still attempt a
down_trylock(). This could still result in a deadlock if one of the
stopped CPUs is holding the semaphore internal spinlock. But this
is a risk that the kernel has been (and continues to be) willing
to take.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20230717194607.145135-3-john.ogness@linutronix.de

It is allowed for consoles to not provide a write() callback. For
example ttynull does this.

Check if a write() callback is available before using it.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20230717194607.145135-2-john.ogness@linutronix.de

Pull printk updates from Petr Mladek:

 - Code cleanup and dead code removal

* tag 'printk-for-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
  printk: Remove obsoleted check for non-existent "user" object
  lib/vsprintf: Use isodigit() for the octal number check
  Remove orphaned CONFIG_PRINTK_SAFE_LOG_BUF_SHIFT

Pull arm64 updates from Will Deacon:
 "ACPI:

   - Improve error reporting when failing to manage SDEI on AGDI device
     removal

  Assembly routines:

   - Improve register constraints so that the compiler can make use of
     the zero register instead of moving an immediate #0 into a GPR

   - Allow the compiler to allocate the registers used for CAS
     instructions

  CPU features and system registers:

   - Cleanups to the way in which CPU features are identified from the
     ID register fields

   - Extend system register definition generation to handle Enum types
     when defining shared register fields

   - Generate definitions for new _EL2 registers and add new fields for
     ID_AA64PFR1_EL1

   - Allow SVE to be disabled separately from SME on the kernel
     command-line

  Tracing:

   - Support for "direct calls" in ftrace, which enables BPF tracing for
     arm64

  Kdump:

   - Don't bother unmapping the crashkernel from the linear mapping,
     which then allows us to use huge (block) mappings and reduce TLB
     pressure when a crashkernel is loaded.

  Memory management:

   - Try again to remove data cache invalidation from the coherent DMA
     allocation path

   - Simplify the fixmap code by mapping at page granularity

   - Allow the kfence pool to be allocated early, preventing the rest of
     the linear mapping from being forced to page granularity

  Perf and PMU:

   - Move CPU PMU code out to drivers/perf/ where it can be reused by
     the 32-bit ARM architecture when running on ARMv8 CPUs

   - Fix race between CPU PMU probing and pKVM host de-privilege

   - Add support for Apple M2 CPU PMU

   - Adjust the generic PERF_COUNT_HW_BRANCH_INSTRUCTIONS event
     dynamically, depending on what the CPU actually supports

   - Minor fixes and cleanups to system PMU drivers

  Stack tracing:

   - Use the XPACLRI instruction to strip PAC from pointers, rather than
     rolling our own function in C

   - Remove redundant PAC removal for toolchains that handle this in
     their builtins

   - Make backtracing more resilient in the face of instrumentation

  Miscellaneous:

   - Fix single-step with KGDB

   - Remove harmless warning when 'nokaslr' is passed on the kernel
     command-line

   - Minor fixes and cleanups across the board"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (72 commits)
  KVM: arm64: Ensure CPU PMU probes before pKVM host de-privilege
  arm64: kexec: include reboot.h
  arm64: delete dead code in this_cpu_set_vectors()
  arm64/cpufeature: Use helper macro to specify ID register for capabilites
  drivers/perf: hisi: add NULL check for name
  drivers/perf: hisi: Remove redundant initialized of pmu->name
  arm64/cpufeature: Consistently use symbolic constants for min_field_value
  arm64/cpufeature: Pull out helper for CPUID register definitions
  arm64/sysreg: Convert HFGITR_EL2 to automatic generation
  ACPI: AGDI: Improve error reporting for problems during .remove()
  arm64: kernel: Fix kernel warning when nokaslr is passed to commandline
  perf/arm-cmn: Fix port detection for CMN-700
  arm64: kgdb: Set PSTATE.SS to 1 to re-enable single-step
  arm64: move PAC masks to <asm/pointer_auth.h>
  arm64: use XPACLRI to strip PAC
  arm64: avoid redundant PAC stripping in __builtin_return_address()
  arm64/sme: Fix some comments of ARM SME
  arm64/signal: Alloc tpidr2 sigframe after checking system_supports_tpidr2()
  arm64/signal: Use system_supports_tpidr2() to check TPIDR2
  arm64/idreg: Don't disable SME when disabling SVE
  ...

Pull asm-generic updates from Arnd Bergmann:
 "These are various cleanups, fixing a number of uapi header files to no
  longer reference CONFIG_* symbols, and one patch that introduces the
  new CONFIG_HAS_IOPORT symbol for architectures that provide working
  inb()/outb() macros, as a preparation for adding driver dependencies
  on those in the following release"

* tag 'asm-generic-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  Kconfig: introduce HAS_IOPORT option and select it as necessary
  scripts: Update the CONFIG_* ignore list in headers_install.sh
  pktcdvd: Remove CONFIG_CDROM_PKTCDVD_WCACHE from uapi header
  Move bp_type_idx to include/linux/hw_breakpoint.h
  Move ep_take_care_of_epollwakeup() to fs/eventpoll.c
  Move COMPAT_ATM_ADDPARTY to net/atm/svc.c

Pull ARM SoC devicetree updates from Arnd Bergmann:
 "The devicetree changes overall are again dominated by the Qualcomm
  Snapdragon platform that weighs in at over 300 changesets, but there
  are many updates across other platforms as well, notably Mediatek,
  NXP, Rockchips, Renesas, TI, Samsung and ST Microelectronics. These
  all add new features for existing machines, as well as new machines
  and SoCs.

  The newly added SoCs are:

   - Allwinner T113-s, an Cortex-A7 based variant of the RISC-V based D1
     chip.

   - StarFive JH7110, a RISC-V SoC based on the Sifive U74 core like its
     JH7100 predecessor, but with additional CPU cores and a GPU.

   - Apple M2 as used in current Macbook Air/Pro and Mac Mini gets
     added, with comparable support as its M1 predecessor.

   - Unisoc UMS512 (Tiger T610) is a midrange smartphone SoC

   - Qualcomm IPQ5332 and IPQ9574 are Wi-Fi 7 networking SoCs, based on
     the Cortex-A53 and Cortex-A73 cores, respectively.

   - Qualcomm sa8775p is an automotive SoC derived from the Snapdragon
     family.

  Including the initial board support for the added SoC platforms, there
  are 52 new machines. The largest group are 19 boards industrial
  embedded boards based on the NXP i.MX6 (32-bit) and i.MX8 (64-bit)
  families.

  Others include:

   - Two boards based on the Allwinner f1c200s ultra-low-cost chip

   - Three 'Banana Pi' variants based on the Amlogic g12b (A311D, S922X)
     SoC.

   - The Gl.Inet mv1000 router based on Marvell Armada 3720

   - A Wifi/LTE Dongle based on Qualcomm msm8916

   - Two robotics boards based on Qualcomm QRB chips

   - Three Snapdragon based phones made by Xiaomi

   - Five developments boards based on various Rockchip SoCs, including
     the rk3588s-khadas-edge2 and a few NanoPi models

   - The AM625 Beagleplay industrial SBC

  Another 14 machines get removed: both boards for the obsolete 'oxnas'
  platform, three boards for the Renesas r8a77950 SoC that were only for
  pre-production chips, and various chromebook models based on the
  Qualcomm Sc7180 'trogdor' design that were never part of products"

* tag 'soc-dt-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (836 commits)
  arm64: dts: rockchip: Add support for volume keys to rk3399-pinephone-pro
  arm64: dts: rockchip: Add vdd_cpu_big regulators to rk3588-rock-5b
  arm64: dts: rockchip: Use generic name for es8316 on Pinebook Pro and Rock 5B
  arm64: dts: rockchip: Drop RTC clock-frequency on rk3588-rock-5b
  arm64: dts: apple: t8112: Add PWM controller
  arm64: dts: apple: t600x: Add PWM controller
  arm64: dts: apple: t8103: Add PWM controller
  arm64: dts: rockchip: Add pinctrl gpio-ranges for rk356x
  ARM: dts: nomadik: Replace deprecated spi-gpio properties
  ARM: dts: aspeed-g6: Add UDMA node
  ARM: dts: aspeed: greatlakes: add mctp device
  ARM: dts: aspeed: greatlakes: Add gpio names
  ARM: dts: aspeed: p10bmc: Change power supply info
  arm64: dts: mediatek: mt6795-xperia-m5: Add Bosch BMM050 Magnetometer
  arm64: dts: mediatek: mt6795-xperia-m5: Add Bosch BMA255 Accelerometer
  arm64: dts: mediatek: mt6795: Add tertiary PWM node
  arm64: dts: rockchip: add panel to Anbernic RG353 series
  dt-bindings: arm: Add Data Modul i.MX8M Plus eDM SBC
  dt-bindings: arm: fsl: Add chargebyte Tarragon
  dt-bindings: vendor-prefixes: add chargebyte
  ...

Pull ARM SoC defconfig updates from Arnd Bergmann:
 "Most of the changes just enable additional device drivers that were
  added or that are often used on major platforms.

  The virtconfig added last time now disables additional drivers to
  shrink kernels for virtual machines.

  The obsolete oxnas_v6_defconfig file is removed in turn"

* tag 'soc-defconfig-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (33 commits)
  ARM: config: Update Vexpress defconfig
  arm64: defconfig: enable building the nvmem-reboot-mode module
  arm64: defconfig: Enable TI ADC driver
  arm64: defconfig: Enable TI TSCADC driver
  arm64: defconfig: Enable security accelerator driver for TI K3 SoCs
  arm64: defconfig: Enable crypto test module
  ARM: multi_v7_defconfig: Add OPTEE support
  ARM: configs: Update U8500 defconfig
  ARM: imx_v4_v5_defconfig: Build CONFIG_IMX_SDMA as module
  arm64: defconfig: Enable IPQ9574 SoC base configs
  ARM: imx_v6_v7_defconfig: Enable Tarragon peripheral drivers
  arm64: defconfig: Enable ARM CoreSight PMU driver
  arm64: defconfig: remove duplicate TYPEC_UCSI & QCOM_PMIC_GLINK
  ARM: configs: remove oxnas_v6_defconfig
  arm64: defconfig: Enable audio drivers for AM62-SK
  arm64: defconfig: Enable drivers for BeaglePlay
  ARM: imx_v6_v7_defconfig: Select CONFIG_DRM_I2C_NXP_TDA998X
  arm64: defconfig: Enable Virtio RNG driver as built in
  arm64: defconfig: Enable CAN PHY transceiver driver
  arm64: defconfig: add PMIC GLINK modules
  ...

Pull ARM SoC driver updates from Arnd Bergmann:
 "The most notable updates this time are for Qualcomm Snapdragon
  platforms. The Inline-Crypto-Engine gets a new DT binding and driver,
  and a number of drivers now support additional Snapdragon variants, in
  particular the rsc, scm, geni, bwm, glink and socinfo, while the llcc
  (edac) and rpm drivers get notable functionality updates.

  Updates on other platforms include:

   - Various updates to the Mediatek mutex and mmsys drivers, including
     support for the Helio X10 SoC

   - Support for unidirectional mailbox channels in Arm SCMI firmware

   - Support for per cpu asynchronous notification in OP-TEE firmware

   - Minor updates for memory controller drivers.

   - Minor updates for Renesas, TI, Amlogic, Apple, Broadcom, Tegra,
     Allwinner, Versatile Express, Canaan, Microchip, Mediatek and i.MX
     SoC drivers, mainly updating the use of MODULE_LICENSE() macros and
     obsolete DT driver interfaces"

* tag 'soc-drivers-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (165 commits)
  soc: ti: smartreflex: Simplify getting the opam_sr pointer
  bus: vexpress-config: Add explicit of_platform.h include
  soc: mediatek: Kconfig: Add MTK_CMDQ dependency to MTK_MMSYS
  memory: mtk-smi: mt8365: Add SMI Support
  dt-bindings: memory-controllers: mediatek,smi-larb: add mt8365
  dt-bindings: memory-controllers: mediatek,smi-common: add mt8365
  memory: tegra: read values from correct device
  dt-bindings: crypto: Add Qualcomm Inline Crypto Engine
  soc: qcom: Make the Qualcomm UFS/SDCC ICE a dedicated driver
  dt-bindings: firmware: document Qualcomm QCM2290 SCM
  soc: qcom: rpmh-rsc: Support RSC v3 minor versions
  soc: qcom: smd-rpm: Use GFP_ATOMIC in write path
  soc/tegra: fuse: Remove nvmem root only access
  soc/tegra: cbb: tegra194: Use of_address_count() helper
  soc/tegra: cbb: Remove MODULE_LICENSE in non-modules
  ARM: tegra: Remove MODULE_LICENSE in non-modules
  soc/tegra: flowctrl: Use devm_platform_get_and_ioremap_resource()
  soc: tegra: cbb: Drop empty platform remove function
  firmware: arm_scmi: Add support for unidirectional mailbox channels
  dt-bindings: firmware: arm,scmi: Support mailboxes unidirectional channels
  ...

Pull ARM SoC updates from Arnd Bergmann:
 "The Oxford Semiconductor OX810/OX820 'Oxnas' platform gets retired
  after the ARM11MPcore processor keeps causing problems in certain
  corner cases. OX820 was the only remaining SoC with this core after
  CNS3xxx got retired, and its driver support was never completely
  merged upstream. The Arm 'Realview' reference platform still supports
  ARM11MPCore in principle, but this was never a product, and the CPU
  support will get cleaned up later on.

  Another series updates the mv78xx0 platform, which has been similarly
  neglected for a while, but should work properly again now.

  The other changes are minor cleanups across platforms, mostly
  converting code to more modern interfaces for DT nodes and removing
  some more code as a follow-up to the large-scale platform removal in
  linux-6.3"

* tag 'soc-arm-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (28 commits)
  ARM: mv78xx0: fix entries for gpios, buttons and usb ports
  ARM: mv78xx0: add code to enable XOR and CRYPTO engines on mv78xx0
  ARM: mv78xx0: set the correct driver for the i2c RTC
  ARM: mv78xx0: adjust init logic for ts-wxl to reflect single core dev
  soc: fsl: Use of_property_present() for testing DT property presence
  ARM: pxa: Use of_property_read_bool() for boolean properties
  firmware: turris-mox-rwtm: make kobj_type structure constant
  ARM: oxnas: remove OXNAS support
  ARM: sh-mobile: Use of_cpu_node_to_id() to read CPU node 'reg'
  ARM: OMAP2+: hwmod: Use kzalloc for allocating only one element
  ARM: OMAP2+: Remove the unneeded result variable
  ARM: OMAP2+: fix repeated words in comments
  ARM: OMAP2+: remove obsolete config OMAP3_SDRC_AC_TIMING
  ARM: OMAP2+: Use of_address_to_resource()
  ARM: OMAP2+: Use of_property_read_bool() for boolean properties
  ARM: omap1: remove redundant variables err
  ARM: omap1: Kconfig: Fix indentation
  ARM: bcm: Use of_address_to_resource()
  ARM: mstar: remove unused config MACH_MERCURY
  ARM: spear: remove obsolete config MACH_SPEAR600
  ...

Pull x86 APIC updates from Thomas Gleixner:

 - Fix the incorrect handling of atomic offset updates in
   reserve_eilvt_offset()

   The check for the return value of atomic_cmpxchg() is not compared
   against the old value, it is compared against the new value, which
   makes it two round on success.

   Convert it to atomic_try_cmpxchg() which does the right thing.

 - Handle IO/APIC less systems correctly

   When IO/APIC is not advertised by ACPI then the computation of the
   lower bound for dynamically allocated interrupts like MSI goes wrong.

   This lower bound is used to exclude the IO/APIC legacy GSI space as
   that must stay reserved for the legacy interrupts.

   In case that the system, e.g. VM, does not advertise an IO/APIC the
   lower bound stays at 0.

   0 is an invalid interrupt number except for the legacy timer
   interrupt on x86. The return value is unchecked in the core code, so
   it ends up to allocate interrupt number 0 which is subsequently
   considered to be invalid by the caller, e.g. the MSI allocation code.

   A similar problem was already cured for device tree based systems
   years ago, but that missed - or did not envision - the zero IO/APIC
   case.

   Consolidate the zero check and return the provided "from" argument to
   the core code call site, which is guaranteed to be greater than 0.

 - Simplify the X2APIC cluster CPU mask logic for CPU hotplug

   Per cluster CPU masks are required for X2APIC in cluster mode to
   determine the correct cluster for a target CPU when calculating the
   destination for IPIs

   These masks are established when CPUs are borught up. The first CPU
   in a cluster must allocate a new cluster CPU mask. As this happens
   during the early startup of a CPU, where memory allocations cannot be
   done, the mask has to be allocated by the control CPU.

   The current implementation allocates a clustermask just in case and
   if the to be brought up CPU is the first in a cluster the CPU takes
   over this allocation from a global pointer.

   This works nicely in the fully serialized CPU bringup scenario which
   is used today, but would fail completely for parallel bringup of
   CPUs.

   The cluster association of a CPU can be computed from the APIC ID
   which is enumerated by ACPI/MADT.

   So the cluster CPU masks can be preallocated and associated upfront
   and the upcoming CPUs just need to set their corresponding bit.

   Aside of preparing for parallel bringup this is a valuable
   simplification on its own.

 - Remove global variables which control the early startup of secondary
   CPUs on 64-bit

   The only information which is needed by a starting CPU is the Linux
   CPU number. The CPU number allows it to retrieve the rest of the
   required data from already existing per CPU storage.

   So instead of initial_stack, early_gdt_desciptor and initial_gs
   provide a new variable smpboot_control which contains the Linux CPU
   number for now. The starting CPU can retrieve and compute all
   required information for startup from there.

   Aside of being a cleanup, this is also preparing for parallel CPU
   bringup, where starting CPUs will look up their Linux CPU number via
   the APIC ID, when smpboot_control has the corresponding control bit
   set.

 - Make cc_vendor globally accesible

   Subsequent parallel bringup changes require access to cc_vendor
   because confidental computing platforms need special treatment in the
   early startup phase vs. CPUID and APCI ID readouts.

   The change makes cc_vendor global and provides stub accessors in case
   that CONFIG_ARCH_HAS_CC_PLATFORM is not set.

   This was merged from the x86/cc branch in anticipation of further
   parallel bringup commits which require access to cc_vendor. Due to
   late discoveries of fundamental issue with those patches these
   commits never happened.

   The merge commit is unfortunately in the middle of the APIC commits
   so unraveling it would have required a rebase or revert. As the
   parallel bringup seems to be well on its way for 6.5 this would be
   just pointless churn. As the commit does not contain any functional
   change it's not a risk to keep it.

* tag 'x86-apic-2023-04-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/ioapic: Don't return 0 from arch_dynirq_lower_bound()
  x86/apic: Fix atomic update of offset in reserve_eilvt_offset()
  x86/coco: Export cc_vendor
  x86/smpboot: Reference count on smpboot_setup_warm_reset_vector()
  x86/smpboot: Remove initial_gs
  x86/smpboot: Remove early_gdt_descr on 64-bit
  x86/smpboot: Remove initial_stack on 64-bit
  x86/apic/x2apic: Allow CPU cluster_mask to be populated in parallel

Pull timers and timekeeping updates from Thomas Gleixner:

 - Improve the VDSO build time checks to cover all dynamic relocations

   VDSO does not allow dynamic relocations, but the build time check is
   incomplete and fragile.

   It's based on architectures specifying the relocation types to search
   for and does not handle R_*_NONE relocation entries correctly.
   R_*_NONE relocations are injected by some GNU ld variants if they
   fail to determine the exact .rel[a]/dyn_size to cover trailing zeros.
   R_*_NONE relocations must be ignored by dynamic loaders, so they
   should be ignored in the build time check too.

   Remove the architecture specific relocation types to check for and
   validate strictly that no other relocations than R_*_NONE end up in
   the VSDO .so file.

 - Prefer signal delivery to the current thread for
   CLOCK_PROCESS_CPUTIME_ID based posix-timers

   Such timers prefer to deliver the signal to the main thread of a
   process even if the context in which the timer expires is the current
   task. This has the downside that it might wake up an idle thread.

   As there is no requirement or guarantee that the signal has to be
   delivered to the main thread, avoid this by preferring the current
   task if it is part of the thread group which shares sighand.

   This not only avoids waking idle threads, it also distributes the
   signal delivery in case of multiple timers firing in the context of
   different threads close to each other better.

 - Align the tick period properly (again)

   For a long time the tick was starting at CLOCK_MONOTONIC zero, which
   allowed users space applications to either align with the tick or to
   place a periodic computation so that it does not interfere with the
   tick. The alignement of the tick period was more by chance than by
   intention as the tick is set up before a high resolution clocksource
   is installed, i.e. timekeeping is still tick based and the tick
   period advances from there.

   The early enablement of sched_clock() broke this alignement as the
   time accumulated by sched_clock() is taken into account when
   timekeeping is initialized. So the base value now(CLOCK_MONOTONIC) is
   not longer a multiple of tick periods, which breaks applications
   which relied on that behaviour.

   Cure this by aligning the tick starting point to the next multiple of
   tick periods, i.e 1000ms/CONFIG_HZ.

 - A set of NOHZ fixes and enhancements:

     * Cure the concurrent writer race for idle and IO sleeptime
       statistics

       The statitic values which are exposed via /proc/stat are updated
       from the CPU local idle exit and remotely by cpufreq, but that
       happens without any form of serialization. As a consequence
       sleeptimes can be accounted twice or worse.

       Prevent this by restricting the accumulation writeback to the CPU
       local idle exit and let the remote access compute the accumulated
       value.

     * Protect idle/iowait sleep time with a sequence count

       Reading idle/iowait sleep time, e.g. from /proc/stat, can race
       with idle exit updates. As a consequence the readout may result
       in random and potentially going backwards values.

       Protect this by a sequence count, which fixes the idle time
       statistics issue, but cannot fix the iowait time problem because
       iowait time accounting races with remote wake ups decrementing
       the remote runqueues nr_iowait counter. The latter is impossible
       to fix, so the only way to deal with that is to document it
       properly and to remove the assertion in the selftest which
       triggers occasionally due to that.

     * Restructure struct tick_sched for better cache layout

     * Some small cleanups and a better cache layout for struct
       tick_sched

 - Implement the missing timer_wait_running() callback for POSIX CPU
   timers

   For unknown reason the introduction of the timer_wait_running()
   callback missed to fixup posix CPU timers, which went unnoticed for
   almost four years.

   While initially only targeted to prevent livelocks between a timer
   deletion and the timer expiry function on PREEMPT_RT enabled kernels,
   it turned out that fixing this for mainline is not as trivial as just
   implementing a stub similar to the hrtimer/timer callbacks.

   The reason is that for CONFIG_POSIX_CPU_TIMERS_TASK_WORK enabled
   systems there is a livelock issue independent of RT.

   CONFIG_POSIX_CPU_TIMERS_TASK_WORK=y moves the expiry of POSIX CPU
   timers out from hard interrupt context to task work, which is handled
   before returning to user space or to a VM. The expiry mechanism moves
   the expired timers to a stack local list head with sighand lock held.
   Once sighand is dropped the task can be preempted and a task which
   wants to delete a timer will spin-wait until the expiry task is
   scheduled back in. In the worst case this will end up in a livelock
   when the preempting task and the expiry task are pinned on the same
   CPU.

   The timer wheel has a timer_wait_running() mechanism for RT, which
   uses a per CPU timer-base expiry lock which is held by the expiry
   code and the task waiting for the timer function to complete blocks
   on that lock.

   This does not work in the same way for posix CPU timers as there is
   no timer base and expiry for process wide timers can run on any task
   belonging to that process, but the concept of waiting on an expiry
   lock can be used too in a slightly different way.

   Add a per task mutex to struct posix_cputimers_work, let the expiry
   task hold it accross the expiry function and let the deleting task
   which waits for the expiry to complete block on the mutex.

   In the non-contended case this results in an extra
   mutex_lock()/unlock() pair on both sides.

   This avoids spin-waiting on a task which is scheduled out, prevents
   the livelock and cures the problem for RT and !RT systems

* tag 'timers-core-2023-04-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  posix-cpu-timers: Implement the missing timer_wait_running callback
  selftests/proc: Assert clock_gettime(CLOCK_BOOTTIME) VS /proc/uptime monotonicity
  selftests/proc: Remove idle time monotonicity assertions
  MAINTAINERS: Remove stale email address
  timers/nohz: Remove middle-function __tick_nohz_idle_stop_tick()
  timers/nohz: Add a comment about broken iowait counter update race
  timers/nohz: Protect idle/iowait sleep time under seqcount
  timers/nohz: Only ever update sleeptime from idle exit
  timers/nohz: Restructure and reshuffle struct tick_sched
  tick/common: Align tick period with the HZ tick.
  selftests/timers/posix_timers: Test delivery of signals across threads
  posix-timers: Prefer delivery of signals to the current thread
  vdso: Improve cmd_vdso_check to check all dynamic relocations

Pull interrupt updates from Thomas Gleixner:
 "Core:

   - Add tracepoints for tasklet callbacks which makes it possible to
     analyze individual tasklet functions instead of guess working from
     the overall duration of tasklet processing

   - Ensure that secondary interrupt threads have their affinity
     adjusted correctly

  Drivers:

   - A large rework of the RISC-V IPI management to prepare for a new
     RISC-V interrupt architecture

   - Small fixes and enhancements all over the place

   - Removal of support for various obsolete hardware platforms and the
     related code"

* tag 'irq-core-2023-04-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits)
  irqchip/st: Remove stih415/stih416 and stid127 platforms support
  irqchip/gic-v3: Add Rockchip 3588001 erratum workaround
  genirq: Update affinity of secondary threads
  softirq: Add trace points for tasklet entry/exit
  irqchip/loongson-pch-pic: Fix pch_pic_acpi_init calling
  irqchip/loongson-pch-pic: Fix registration of syscore_ops
  irqchip/loongson-eiointc: Fix registration of syscore_ops
  irqchip/loongson-eiointc: Fix incorrect use of acpi_get_vec_parent
  irqchip/loongson-eiointc: Fix returned value on parsing MADT
  irqchip/riscv-intc: Add empty irq_eoi() for chained irq handlers
  RISC-V: Use IPIs for remote icache flush when possible
  RISC-V: Use IPIs for remote TLB flush when possible
  RISC-V: Allow marking IPIs as suitable for remote FENCEs
  RISC-V: Treat IPIs as normal Linux IRQs
  irqchip/riscv-intc: Allow drivers to directly discover INTC hwnode
  RISC-V: Clear SIP bit only when using SBI IPI operations
  irqchip/irq-sifive-plic: Add syscore callbacks for hibernation
  irqchip: Use of_property_read_bool() for boolean properties
  irqchip/bcm-6345-l1: Request memory region
  irqchip/gicv3: Workaround for NVIDIA erratum T241-FABRIC-4
  ...

Pull core entry/ptrace update from Thomas Gleixner:
 "Provide a ptrace set/get interface for syscall user dispatch. The main
  purpose is to enable checkpoint/restore (CRIU) to handle processes
  which utilize syscall user dispatch correctly"

* tag 'core-entry-2023-04-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  selftest, ptrace: Add selftest for syscall user dispatch config api
  ptrace: Provide set/get interface for syscall user dispatch
  syscall_user_dispatch: Untag selector address before access_ok()
  syscall_user_dispatch: Split up set_syscall_user_dispatch()

Pull core debugobjects update from Thomas Gleixner:
 "A single update to debugobjects:

  Prevent a race vs statically initialized objects. Such objects are
  usually not initialized via an init() function. They are special cased
  and detected on first use under the assumption that they are already
  correctly initialized via the static initializer.

  This works correctly unless there are two concurrent debug object
  operations on such an object.

  The first one detects that the object is not yet tracked and tries to
  establish a tracking object after dropping the debug objects hash
  bucket lock. The concurrent operation does the same. The one which
  wins the race ends up modifying the state of the object which makes
  the other one fail resulting in a bogus debug objects warning.

  Prevent this by making the detection of a static object and the
  allocation of a tracking object atomic under the hash bucket lock. So
  the first one to acquire the hash bucket lock will succeed and the
  second one will observe the correct tracking state.

  This race existed forever but was only exposed when the timer wheel
  code added a debug_object_assert_init() call outside of the timer base
  locked region. This replaced the previous warning about
  timer::function being NULL which had to be removed when the
  timer_shutdown() mechanics were added"

* tag 'core-debugobjects-2023-04-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  debugobject: Prevent init race with static objects

Pull x86 SEV updates from Borislav Petkov:

 - Add the necessary glue so that the kernel can run as a confidential
   SEV-SNP vTOM guest on Hyper-V. A vTOM guest basically splits the
   address space in two parts: encrypted and unencrypted. The use case
   being running unmodified guests on the Hyper-V confidential computing
   hypervisor

 - Double-buffer messages between the guest and the hardware PSP device
   so that no partial buffers are copied back'n'forth and thus potential
   message integrity and leak attacks are possible

 - Name the return value the sev-guest driver returns when the hw PSP
   device hasn't been called, explicitly

 - Cleanups

* tag 'x86_sev_for_v6.4_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/hyperv: Change vTOM handling to use standard coco mechanisms
  init: Call mem_encrypt_init() after Hyper-V hypercall init is done
  x86/mm: Handle decryption/re-encryption of bss_decrypted consistently
  Drivers: hv: Explicitly request decrypted in vmap_pfn() calls
  x86/hyperv: Reorder code to facilitate future work
  x86/ioremap: Add hypervisor callback for private MMIO mapping in coco VM
  x86/sev: Change snp_guest_issue_request()'s fw_err argument
  virt/coco/sev-guest: Double-buffer messages
  crypto: ccp: Get rid of __sev_platform_init_locked()'s local function pointer
  crypto: ccp - Name -1 return value as SEV_RET_NO_FW_CALL

Pull x86 paravirt updates from Borislav Petkov:

 - Convert a couple of paravirt callbacks to asm to prevent
   '-fzero-call-used-regs' builds from zeroing live registers because
   paravirt hides the CALLs from the compiler so latter doesn't know
   there's a CALL in the first place

 - Merge two paravirt callbacks into one, as their functionality is
   identical

* tag 'x86_paravirt_for_v6.4_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/paravirt: Convert simple paravirt functions to asm
  x86/paravirt: Merge activate_mm() and dup_mmap() callbacks

Pull misc x86 updates from Borislav Petkov:

 - Add a x86 hw vulnerabilities section to MAINTAINERS so that the folks
   involved in it can get CCed on patches

 - Add some more CPUID leafs to the kcpuid tool and extend its
   functionality to be more useful when grepping for CPUID bits

* tag 'x86_misc_for_v6.4_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  MAINTAINERS: Add x86 hardware vulnerabilities section
  tools/x86/kcpuid: Dump the CPUID function in detailed view
  tools/x86/kcpuid: Update AMD leaf Fn80000001
  tools/x86/kcpuid: Fix avx512bw and avx512lvl fields in Fn00000007

Pull x86 cpu model updates from Borislav Petkov:

 - Add Emerald Rapids to the list of Intel models supporting PPIN

 - Finally use a CPUID bit for split lock detection instead of
   enumerating every model

 - Make sure automatic IBRS is set on AMD, even though the AP bringup
   code does that now by replicating the MSR which contains the switch

* tag 'x86_cpu_for_v6.4_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/cpu: Add Xeon Emerald Rapids to list of CPUs that support PPIN
  x86/split_lock: Enumerate architectural split lock disable bit
  x86/CPU/AMD: Make sure EFER[AIBRSE] is set

Pull x86 ACPI update from Borislav Petkov:

 - Improve code generation in ACPI's global lock's acquisition function

* tag 'x86_acpi_for_v6.4_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/ACPI/boot: Improve __acpi_acquire_global_lock

Pull RAS updates from Borislav Petkov:

 - Just cleanups and fixes this time around: make threshold_ktype const,
   an objtool fix and use proper size for a bitmap

* tag 'ras_core_for_v6.4_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/MCE/AMD: Use an u64 for bank_map
  x86/mce: Always inline old MCA stubs
  x86/MCE/AMD: Make kobj_type structure constant

Pull EDAC updates from Borislav Petkov:

 - skx_edac: Fix overflow when decoding 32G DIMM ranks

 - i10nm_edac: Add Sierra Forest support

 - amd64_edac: Split driver code between legacy and SMCA systems. The
   final goal is adding support for more hw, like GPUs

 - The usual minor cleanups and fixes

* tag 'edac_updates_for_v6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras: (25 commits)
  EDAC/i10nm: Add Intel Sierra Forest server support
  EDAC/amd64: Fix indentation in umc_determine_edac_cap()
  EDAC/altera: Remove MODULE_LICENSE in non-module
  EDAC: Sanitize MODULE_AUTHOR strings
  EDAC/amd81[13]1: Remove trailing newline from MODULE_AUTHOR
  EDAC/amd64: Add get_err_info() to pvt->ops
  EDAC/amd64: Split dump_misc_regs() into dct/umc functions
  EDAC/amd64: Split init_csrows() into dct/umc functions
  EDAC/amd64: Split determine_edac_cap() into dct/umc functions
  EDAC/amd64: Rename f17h_determine_edac_ctl_cap()
  EDAC/amd64: Split setup_mci_misc_attrs() into dct/umc functions
  EDAC/amd64: Split ecc_enabled() into dct/umc functions
  EDAC/amd64: Split read_mc_regs() into dct/umc functions
  EDAC/amd64: Split determine_memory_type() into dct/umc functions
  EDAC/amd64: Split read_base_mask() into dct/umc functions
  EDAC/amd64: Split prep_chip_selects() into dct/umc functions
  EDAC/amd64: Rework hw_info_{get,put}
  EDAC/amd64: Merge struct amd64_family_type into struct amd64_pvt
  EDAC/amd64: Do not discover ECC symbol size for Family 17h and later
  EDAC/amd64: Drop dbam_to_cs() for Family 17h and later
  ...

Pull m68k updates from Geert Uytterhoeven:

 - defconfig updates

 - miscellaneous fixes and improvements

* tag 'm68k-for-v6.4-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k:
  m68k: kexec: Include <linux/reboot.h>
  m68k: defconfig: Update defconfigs for v6.3-rc1
  m68k: Remove obsolete config NO_KERNEL_MSG
  nubus: Drop noop match function

Pull trivial nios2 cleanup from Al Viro.

* tag 'pull-nios2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  nios2: _TIF_ALLWORK_MASK is unused

Pull misc vfs pile from Al Viro.

Random minor cleanups.

* tag 'pull-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: Fix description of vfs_tmpfile()
  sysv: switch to put_and_unmap_page()
  fs/sysv: Don't round down address for kunmap_flush_on_unmap()

Pull legacy dio cleanup from Al Viro.

* tag 'pull-old-dio' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  __blockdev_direct_IO(): get rid of submit_io callback

Pull vfs write_one_page removal from Al Viro:
 "write_one_page series"

* tag 'pull-write-one-page' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  mm,jfs: move write_one_page/folio_write_one to jfs
  ocfs2: don't use write_one_page in ocfs2_duplicate_clusters_by_page
  ufs: don't flush page immediately for DIRSYNC directories

Pull vfs fget updates from Al Viro:
 "fget() to fdget() conversions"

* tag 'pull-fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fuse_dev_ioctl(): switch to fdget()
  cgroup_get_from_fd(): switch to fdget_raw()
  bpf: switch to fdget_raw()
  build_mount_idmapped(): switch to fdget()
  kill the last remaining user of proc_ns_fget()
  SVM-SEV: convert the rest of fget() uses to fdget() in there
  convert sgx_set_attribute() to fdget()/fdput()
  convert setns(2) to fdget()/fdput()

Pull erofs updates from Gao Xiang:
 "In this cycle, sub-page block support for uncompressed files is
  available. It's mainly used to enable original signing ('golden')
  4k-block images on arm64 with 16/64k pages. In addition, end users
  could also use this feature to build a manifest to directly refer to
  golden tar data.

  Besides, long xattr name prefix support is also introduced in this
  cycle to avoid too many xattrs with the same prefix (e.g. overlayfs
  xattrs). It's useful for erofs + overlayfs combination (like Composefs
  model): the image size is reduced by ~14% and runtime performance is
  also slightly improved.

  Others are random fixes and cleanups as usual.

  Summary:

   - Add sub-page block size support for uncompressed files

   - Support flattened block device for multi-blob images to be attached
     into virtual machines (including cloud servers) and bare metals

   - Support long xattr name prefixes to optimize images with common
     xattr namespaces (e.g. files with overlayfs xattrs) use cases

   - Various minor cleanups & fixes"

* tag 'erofs-for-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
  erofs: cleanup i_format-related stuffs
  erofs: sunset erofs_dbg()
  erofs: fix potential overflow calculating xattr_isize
  erofs: get rid of z_erofs_fill_inode()
  erofs: enable long extended attribute name prefixes
  erofs: handle long xattr name prefixes properly
  erofs: add helpers to load long xattr name prefixes
  erofs: introduce on-disk format for long xattr name prefixes
  erofs: move packed inode out of the compression part
  erofs: keep meta inode into erofs_buf
  erofs: initialize packed inode after root inode is assigned
  erofs: stop parsing non-compact HEAD index if clusterofs is invalid
  erofs: don't warn ztailpacking feature anymore
  erofs: simplify erofs_xattr_generic_get()
  erofs: rename init_inode_xattrs with erofs_ prefix
  erofs: move several xattr helpers into xattr.c
  erofs: tidy up EROFS on-disk naming
  erofs: support flattened block device for multi-blob images
  erofs: set block size to the on-disk block size
  erofs: avoid hardcoded blocksize for subpage block support

Pull vfs open fixlet from Christian Brauner:
 "EINVAL ist keinmal: This contains the changes to make O_DIRECTORY when
  specified together with O_CREAT an invalid request.

  The wider background is that a regression report about the behavior of
  O_DIRECTORY | O_CREAT was sent to fsdevel about a behavior that was
  changed multiple years and LTS releases earlier during v5.7
  development.

  This has also been covered in

        https://lwn.net/Articles/926782/

  which provides an excellent summary of the discussion"

* tag 'v6.4/vfs.open' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  open: return EINVAL for O_DIRECTORY | O_CREAT

Pull misc vfs updates from Christian Brauner:
 "This contains a pile of various smaller fixes. Most of them aren't
  very interesting so this just highlights things worth mentioning:

   - Various filesystems contained the same little helper to convert
     from the mode of a dentry to the DT_* type of that dentry.

     They have now all been switched to rely on the generic
     fs_umode_to_dtype() helper. All custom helpers are removed (Jeff)

   - Fsnotify now reports ACCESS and MODIFY events for splice
     (Chung-Chiang Cheng)

   - After converting timerfd a long time ago to rely on
     wait_event_interruptible_*() apis, convert eventfd as well. This
     removes the complex open-coded wait code (Wen Yang)

   - Simplify sysctl registration for devpts, avoiding the declaration
     of two tables. Instead, just use a prefixed path with
     register_sysctl() (Luis)

   - The setattr_should_drop_sgid() helper is now exported so NFS can
     use it. By switching NFS to this helper an NFS setgid inheritance
     bug is fixed (me)"

* tag 'v6.4/vfs.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  fs: hfsplus: remove WARN_ON() from hfsplus_cat_{read,write}_inode()
  pnode: pass mountpoint directly
  eventfd: use wait_event_interruptible_locked_irq() helper
  splice: report related fsnotify events
  fs: consolidate duplicate dt_type helpers
  nfs: use vfs setgid helper
  Update relatime comments to include equality
  fs/buffer: Remove redundant assignment to err
  fs_context: drop the unused lsm_flags member
  fs/namespace: fnic: Switch to use %ptTd
  Documentation: update idmappings.rst
  devpts: simplify two-level sysctl registration for pty_kern_table
  eventpoll: align comment with nested epoll limitation

Pull acl updates from Christian Brauner:
 "After finishing the introduction of the new posix acl api last cycle
  the generic POSIX ACL xattr handlers are still around in the
  filesystems xattr handlers for two reasons:

   (1) Because a few filesystems rely on the ->list() method of the
       generic POSIX ACL xattr handlers in their ->listxattr() inode
       operation.

   (2) POSIX ACLs are only available if IOP_XATTR is raised. The
       IOP_XATTR flag is raised in inode_init_always() based on whether
       the sb->s_xattr pointer is non-NULL. IOW, the registered xattr
       handlers of the filesystem are used to raise IOP_XATTR. Removing
       the generic POSIX ACL xattr handlers from all filesystems would
       risk regressing filesystems that only implement POSIX ACL support
       and no other xattrs (nfs3 comes to mind).

  This contains the work to decouple POSIX ACLs from the IOP_XATTR flag
  as they don't depend on xattr handlers anymore. So it's now possible
  to remove the generic POSIX ACL xattr handlers from the sb->s_xattr
  list of all filesystems. This is a crucial step as the generic POSIX
  ACL xattr handlers aren't used for POSIX ACLs anymore and POSIX ACLs
  don't depend on the xattr infrastructure anymore.

  Adressing problem (1) will require more long-term work. It would be
  best to get rid of the ->list() method of xattr handlers completely at
  some point.

  For erofs, ext{2,4}, f2fs, jffs2, ocfs2, and reiserfs the nop POSIX
  ACL xattr handler is kept around so they can continue to use
  array-based xattr handler indexing.

  This update does simplify the ->listxattr() implementation of all
  these filesystems however"

* tag 'v6.4/vfs.acl' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  acl: don't depend on IOP_XATTR
  ovl: check for ->listxattr() support
  reiserfs: rework priv inode handling
  fs: rename generic posix acl handlers
  reiserfs: rework ->listxattr() implementation
  fs: simplify ->listxattr() implementation
  fs: drop unused posix acl handlers
  xattr: remove unused argument
  xattr: add listxattr helper
  xattr: simplify listxattr helpers

Pull pidfd updates from Christian Brauner:
 "This adds a new pidfd_prepare() helper which allows the caller to
  reserve a pidfd number and allocates a new pidfd file that stashes the
  provided struct pid.

  It should be avoided installing a file descriptor into a task's file
  descriptor table just to close it again via close_fd() in case an
  error occurs. The fd has been visible to userspace and might already
  be in use. Instead, a file descriptor should be reserved but not
  installed into the caller's file descriptor table.

  If another failure path is hit then the reserved file descriptor and
  file can just be put without any userspace visible side-effects. And
  if all failure paths are cleared the file descriptor and file can be
  installed into the task's file descriptor table.

  This helper is now used in all places that open coded this
  functionality before. For example, this is currently done during
  copy_process() and fanotify used pidfd_create(), which returns a pidfd
  that has already been made visibile in the caller's file descriptor
  table, but then closed it using close_fd().

  In one of the next merge windows there is also new functionality
  coming to unix domain sockets that will have to rely on
  pidfd_prepare()"

* tag 'v6.4/pidfd.file' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
  fanotify: use pidfd_prepare()
  fork: use pidfd_prepare()
  pid: add pidfd_prepare()

Pull user work thread updates from Christian Brauner:
 "This contains the work generalizing the ability to create a kernel
  worker from a userspace process.

  Such user workers will run with the same credentials as the userspace
  process they were created from providing stronger security and
  accounting guarantees than the traditional override_creds() approach
  ever could've hoped for.

  The original work was heavily based and optimzed for the needs of
  io_uring which was the first user. However, as it quickly turned out
  the ability to create user workers inherting properties from a
  userspace process is generally useful.

  The vhost subsystem currently creates workers using the kthread api.
  The consequences of using the kthread api are that RLIMITs don't work
  correctly as they are inherited from khtreadd. This leads to bugs
  where more workers are created than would be allowed by the RLIMITs of
  the userspace process in lieu of which workers are created.

  Problems like this disappear with user workers created from the
  userspace processes for which they perform the work. In addition,
  providing this api allows vhost to remove additional complexity. For
  example, cgroup and mm sharing will just work out of the box with user
  workers based on the relevant userspace process instead of manually
  ensuring the correct cgroup and mm contexts are used.

  So the vhost subsystem should simply be made to use the same mechanism
  as io_uring. To this end the original mechanism used for
  create_io_thread() is generalized into user workers:

   - Introduce PF_USER_WORKER as a generic indicator that a given task
     is a user worker, i.e., a kernel task that was created from a
     userspace process. Now a PF_IO_WORKER thread is just a specialized
     version of PF_USER_WORKER. So io_uring io workers raise both flags.

   - Make copy_process() available to core kernel code

   - Extend struct kernel_clone_args with the following bitfields
     allowing to indicate to copy_process():
       - to create a user worker (raise PF_USER_WORKER)
       - to not inherit any files from the userspace process
       - to ignore signals

  After all generic changes are in place the vhost subsystem implements
  a new dedicated vhost api based on user workers. Finally, vhost is
  switched to rely on the new api moving it off of kthreads.

  Thanks to Mike for sticking it out and making it through this rather
  arduous journey"

* tag 'v6.4/kernel.user_worker' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
  vhost: use vhost_tasks for worker threads
  vhost: move worker thread fields to new struct
  vhost_task: Allow vhost layer to use copy_process
  fork: allow kernel code to call copy_process
  fork: Add kernel_clone_args flag to ignore signals
  fork: add kernel_clone_args flag to not dup/clone files
  fork/vm: Move common PF_IO_WORKER behavior to new flag
  kernel: Make io_thread and kthread bit fields
  kthread: Pass in the thread's name during creation
  kernel: Allow a kernel thread's name to be set in copy_process
  csky: Remove kernel_thread declaration

Pull clone3 selftest fix from Christian Brauner:
 "This is a single fix to the clone3() selftstests.

  It fell through the sefltest tree cracks a few times so I'll provide
  it here. It has low urgency but we should still correctly report the
  number of tests"

* tag 'v6.4/kernel.clone3.tests' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
  selftests/clone3: fix number of tests in ksft_set_plan

Pull documentation updates from Jonathan Corbet:
 "Commit volume in documentation is relatively low this time, but there
  is still a fair amount going on, including:

   - Reorganize the architecture-specific documentation under
     Documentation/arch

     This makes the structure match the source directory and helps to
     clean up the mess that is the top-level Documentation directory a
     bit. This work creates the new directory and moves x86 and most of
     the less-active architectures there.

     The current plan is to move the rest of the architectures in 6.5,
     with the patches going through the appropriate subsystem trees.

   - Some more Spanish translations and maintenance of the Italian
     translation

   - A new "Kernel contribution maturity model" document from Ted

   - A new tutorial on quickly building a trimmed kernel from Thorsten

  Plus the usual set of updates and fixes"

* tag 'docs-6.4' of git://git.lwn.net/linux: (47 commits)
  media: Adjust column width for pdfdocs
  media: Fix building pdfdocs
  docs: clk: add documentation to log which clocks have been disabled
  docs: trace: Fix typo in ftrace.rst
  Documentation/process: always CC responsible lists
  docs: kmemleak: adjust to config renaming
  ELF: document some de-facto PT_* ABI quirks
  Documentation: arm: remove stih415/stih416 related entries
  docs: turn off "smart quotes" in the HTML build
  Documentation: firmware: Clarify firmware path usage
  docs/mm: Physical Memory: Fix grammar
  Documentation: Add document for false sharing
  dma-api-howto: typo fix
  docs: move m68k architecture documentation under Documentation/arch/
  docs: move parisc documentation under Documentation/arch/
  docs: move ia64 architecture docs under Documentation/arch/
  docs: Move arc architecture docs under Documentation/arch/
  docs: move nios2 documentation under Documentation/arch/
  docs: move openrisc documentation under Documentation/arch/
  docs: move superh documentation under Documentation/arch/
  ...

Merge tag 'linux-kselftest-kunit-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull KUnit updates from Shuah Khan:

 - several fixes to kunit tool

 - new klist structure test

 - support for m68k under QEMU

 - support for overriding the QEMU serial port

 - support for SH under QEMU

* tag 'linux-kselftest-kunit-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  kunit: add tests for using current KUnit test field
  kunit: tool: Add support for SH under QEMU
  kunit: tool: Add support for overriding the QEMU serial port
  .gitignore: Unignore .kunitconfig
  list: test: Test the klist structure
  kunit: increase KUNIT_LOG_SIZE to 2048 bytes
  kunit: Use gfp in kunit_alloc_resource() kernel-doc
  kunit: tool: fix pre-existing `mypy --strict` errors and update run_checks.py
  kunit: tool: remove unused imports and variables
  kunit: tool: add subscripts for type annotations where appropriate
  kunit: fix bug of extra newline characters in debugfs logs
  kunit: fix bug in the order of lines in debugfs logs
  kunit: fix bug in debugfs logs of parameterized tests
  kunit: tool: Add support for m68k under QEMU

Merge tag 'linux-kselftest-next-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull Kselftest updates from Shuah Khan:

 - several patches to enhance and fix resctrl test

 - nolibc support for kselftest with an addition to vprintf() to
   tools/nolibc/stdio and related test changes

 - Refactor 'peeksiginfo' ptrace test part

 - add 'malloc' failures checks in cgroup test_memcontrol

 - a new prctl test

 - enhancements sched test with additional ore schedule prctl calls

* tag 'linux-kselftest-next-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (25 commits)
  selftests/resctrl: Fix incorrect error return on test complete
  selftests/resctrl: Remove duplicate codes that clear each test result file
  selftests/resctrl: Commonize the signal handler register/unregister for all tests
  selftests/resctrl: Cleanup properly when an error occurs in CAT test
  selftests/resctrl: Flush stdout file buffer before executing fork()
  selftests/resctrl: Return MBA check result and make it to output message
  selftests/resctrl: Fix set up schemata with 100% allocation on first run in MBM test
  selftests/resctrl: Use correct exit code when tests fail
  kselftest/arm64: Convert za-fork to use kselftest.h
  kselftest: Support nolibc
  tools/nolibc/stdio: Implement vprintf()
  selftests/resctrl: Correct get_llc_perf() param in function comment
  selftests/resctrl: Use remount_resctrlfs() consistently with boolean
  selftests/resctrl: Change name from CBM_MASK_PATH to INFO_PATH
  selftests/resctrl: Change initialize_llc_perf() return type to void
  selftests/resctrl: Replace obsolete memalign() with posix_memalign()
  selftests/resctrl: Check for return value after write_schemata()
  selftests/resctrl: Allow ->setup() to return errors
  selftests/resctrl: Move ->setup() call outside of test specific branches
  selftests/resctrl: Return NULL if malloc_and_init_memory() did not alloc mem
  ...

Pull RCU updates from Joel Fernandes:

 - Updates and additions to MAINTAINERS files, with Boqun being added to
   the RCU entry and Zqiang being added as an RCU reviewer.

   I have also transitioned from reviewer to maintainer; however, Paul
   will be taking over sending RCU pull-requests for the next merge
   window.

 - Resolution of hotplug warning in nohz code, achieved by fixing
   cpu_is_hotpluggable() through interaction with the nohz subsystem.

   Tick dependency modifications by Zqiang, focusing on fixing usage of
   the TICK_DEP_BIT_RCU_EXP bitmask.

 - Avoid needless calls to the rcu-lazy shrinker for CONFIG_RCU_LAZY=n
   kernels, fixed by Zqiang.

 - Improvements to rcu-tasks stall reporting by Neeraj.

 - Initial renaming of k[v]free_rcu() to k[v]free_rcu_mightsleep() for
   increased robustness, affecting several components like mac802154,
   drbd, vmw_vmci, tracing, and more.

   A report by Eric Dumazet showed that the API could be unknowingly
   used in an atomic context, so we'd rather make sure they know what
   they're asking for by being explicit:

      https://lore.kernel.org/all/20221202052847.2623997-1-edumazet@google.com/

 - Documentation updates, including corrections to spelling,
   clarifications in comments, and improvements to the srcu_size_state
   comments.

 - Better srcu_struct cache locality for readers, by adjusting the size
   of srcu_struct in support of SRCU usage by Christoph Hellwig.

 - Teach lockdep to detect deadlocks between srcu_read_lock() vs
   synchronize_srcu() contributed by Boqun.

   Previously lockdep could not detect such deadlocks, now it can.

 - Integration of rcutorture and rcu-related tools, targeted for v6.4
   from Boqun's tree, featuring new SRCU deadlock scenarios, test_nmis
   module parameter, and more

 - Miscellaneous changes, various code cleanups and comment improvements

* tag 'rcu.6.4.april5.2023.3' of git://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux: (71 commits)
  checkpatch: Error out if deprecated RCU API used
  mac802154: Rename kfree_rcu() to kvfree_rcu_mightsleep()
  rcuscale: Rename kfree_rcu() to kfree_rcu_mightsleep()
  ext4/super: Rename kfree_rcu() to kfree_rcu_mightsleep()
  net/mlx5: Rename kfree_rcu() to kfree_rcu_mightsleep()
  net/sysctl: Rename kvfree_rcu() to kvfree_rcu_mightsleep()
  lib/test_vmalloc.c: Rename kvfree_rcu() to kvfree_rcu_mightsleep()
  tracing: Rename kvfree_rcu() to kvfree_rcu_mightsleep()
  misc: vmw_vmci: Rename kvfree_rcu() to kvfree_rcu_mightsleep()
  drbd: Rename kvfree_rcu() to kvfree_rcu_mightsleep()
  rcu: Protect rcu_print_task_exp_stall() ->exp_tasks access
  rcu: Avoid stack overflow due to __rcu_irq_enter_check_tick() being kprobe-ed
  rcu-tasks: Report stalls during synchronize_srcu() in rcu_tasks_postscan()
  rcu: Permit start_poll_synchronize_rcu_expedited() to be invoked early
  rcu: Remove never-set needwake assignment from rcu_report_qs_rdp()
  rcu: Register rcu-lazy shrinker only for CONFIG_RCU_LAZY=y kernels
  rcu: Fix missing TICK_DEP_MASK_RCU_EXP dependency check
  rcu: Fix set/clear TICK_DEP_BIT_RCU_EXP bitmask race
  rcu/trace: use strscpy() to instead of strncpy()
  tick/nohz: Fix cpu_is_hotpluggable() by checking with nohz subsystem
  ...