The only remaining consumer is new_inode, where it showed up in 2001 as
commit c37fa164f793 ("v2.4.9.9 -> v2.4.9.10") in a historical repo [1]
with a changelog which does not mention it.

Since then the line got only touched up to keep compiling.

While it may have been of benefit back in the day, it is guaranteed to
at best not get in the way in the multicore setting -- as the code
performs *a lot* of work between the prefetch and actual lock acquire,
any contention means the cacheline is already invalid by the time the
routine calls spin_lock().  It adds spurious traffic, for short.

On top of it prefetch is notoriously tricky to use for single-threaded
purposes, making it questionable from the get go.

As such, remove it.

I admit upfront I did not see value in benchmarking this change, but I
can do it if that is deemed appropriate.

Removal from new_inode and of the entire thing are in the same patch as
requested by Linus, so whatever weird looks can be directed at that guy.

Link: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/fs/inode.c?id=c37fa164f793735b32aa3f53154ff1a7659e6442 [1]
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

An otherwise correct change to the atomic operations uncovered an
existing bug in the sparc __arch_xchg() function, which is calls
__xchg_called_with_bad_pointer() when its arguments are unknown at
compile time:

ERROR: modpost: "__xchg_called_with_bad_pointer" [lib/atomic64_test.ko] undefined!

This now happens because gcc determines that it's better to not inline the
function. Avoid this by just marking the function as __always_inline
to force the compiler to do the right thing here.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/all/c525adc9-6623-4660-8718-e0c9311563b8@roeck-us.net/
Fixes: d12157efc8e08 ("locking/atomic: make atomic*_{cmp,}xchg optional")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://lore.kernel.org/r/20230628094938.2318171-1-arnd@kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>

Pull drm updates from Dave Airlie:
 "There is one set of patches to misc for a i915 gsc/mei proxy driver.

  Otherwise it's mostly amdgpu/i915/msm, lots of hw enablement and lots
  of refactoring.

  core:
   - replace strlcpy with strscpy
   - EDID changes to support further conversion to struct drm_edid
   - Move i915 DSC parameter code to common DRM helpers
   - Add Colorspace functionality

  aperture:
   - ignore framebuffers with non-primary devices

  fbdev:
   - use fbdev i/o helpers
   - add Kconfig options for fb_ops helpers
   - use new fb io helpers directly in drivers

  sysfs:
   - export DRM connector ID

  scheduler:
   - Avoid an infinite loop

  ttm:
   - store function table in .rodata
   - Add query for TTM mem limit
   - Add NUMA awareness to pools
   - Export ttm_pool_fini()

  bridge:
   - fsl-ldb: support i.MX6SX
   - lt9211, lt9611: remove blanking packets
   - tc358768: implement input bus formats, devm cleanups
   - ti-snd65dsi86: implement wait_hpd_asserted
   - analogix: fix endless probe loop
   - samsung-dsim: support swapped clock, fix enabling, support var
     clock
   - display-connector: Add support for external power supply
   - imx: Fix module linking
   - tc358762: Support reset GPIO

  panel:
   - nt36523: Support Lenovo J606F
   - st7703: Support Anbernic RG353V-V2
   - InnoLux G070ACE-L01 support
   - boe-tv101wum-nl6: Improve initialization
   - sharp-ls043t1le001: Mode fixes
   - simple: BOE EV121WXM-N10-1850, S6D7AA0
   - Ampire AM-800480L1TMQW-T00H
   - Rocktech RK043FN48H
   - Starry himax83102-j02
   - Starry ili9882t

  amdgpu:
   - add new ctx query flag to handle reset better
   - add new query/set shadow buffer for rdna3
   - DCN 3.2/3.1.x/3.0.x updates
   - Enable DC_FP on loongarch
   - PCIe fix for RDNA2
   - improve DC FAMS/SubVP support for better power management
   - partition support for lots of engines
   - Take NUMA into account when allocating memory
   - Add new DRM_AMDGPU_WERROR config parameter to help with CI
   - Initial SMU13 overdrive support
   - Add support for new colorspace KMS API
   - W=1 fixes

  amdkfd:
   - Query TTM mem limit rather than hardcoding it
   - GC 9.4.3 partition support
   - Handle NUMA for partitions
   - Add debugger interface for enabling gdb
   - Add KFD event age tracking

  radeon:
   - Fix possible UAF

  i915:
   - new getparam for PXP support
   - GSC/MEI proxy driver
   - Meteorlake display enablement
   - avoid clearing preallocated framebuffers with TTM
   - implement framebuffer mmap support
   - Disable sampler indirect state in bindless heap
   - Enable fdinfo for GuC backends
   - GuC loading and firmware table handling fixes
   - Various refactors for multi-tile enablement
   - Define MOCS and PAT tables for MTL
   - GSC/MEI support for Meteorlake
   - PMU multi-tile support
   - Large driver kernel doc cleanup
   - Allow VRR toggling and arbitrary refresh rates
   - Support async flips on linear buffers on display ver 12+
   - Expose CRTC CTM property on ILK/SNB/VLV
   - New debugfs for display clock frequencies
   - Hotplug refactoring
   - Display refactoring
   - I915_GEM_CREATE_EXT_SET_PAT for Mesa on Meteorlake
   - Use large rings for compute contexts
   - HuC loading for MTL
   - Allow user to set cache at BO creation
   - MTL powermanagement enhancements
   - Switch to dedicated workqueues to stop using flush_scheduled_work()
   - Move display runtime init under display/
   - Remove 10bit gamma on desktop gen3 parts, they don't support it

  habanalabs:
   - uapi: return 0 for user queries if there was a h/w or f/w error
   - Add pci health check when we lose connection with the firmware.
     This can be used to distinguish between pci link down and firmware
     getting stuck.
   - Add more info to the error print when TPC interrupt occur.
   - Firmware fixes

  msm:
   - Adreno A660 bindings
   - SM8350 MDSS bindings fix
   - Added support for DPU on sm6350 and sm6375 platforms
   - Implemented tearcheck support to support vsync on SM150 and newer
     platforms
   - Enabled missing features (DSPP, DSC, split display) on sc8180x,
     sc8280xp, sm8450
   - Added support for DSI and 28nm DSI PHY on MSM8226 platform
   - Added support for DSI on sm6350 and sm6375 platforms
   - Added support for display controller on MSM8226 platform
   - A690 GPU support
   - Move cmdstream dumping out of fence signaling path
   - a610 support
   - Support for a6xx devices without GMU

  nouveau:
   - NULL ptr before deref fixes

  armada:
   - implement fbdev emulation as client

  sun4i:
   - fix mipi-dsi dotclock
   - release clocks

  vc4:
   - rgb range toggle property
   - BT601 / BT2020 HDMI support

  vkms:
   - convert to drmm helpers
   - add reflection and rotation support
   - fix rgb565 conversion

  gma500:
   - fix iomem access

  shmobile:
   - support renesas soc platform
   - enable fbdev

  mxsfb:
   - Add support for i.MX93 LCDIF

  stm:
   - dsi: Use devm_ helper
   - ltdc: Fix potential invalid pointer deref

  renesas:
   - Group drivers in renesas subdirectory to prepare for new platform
   - Drop deprecated R-Car H3 ES1.x support

  meson:
   - Add support for MIPI DSI displays

  virtio:
   - add sync object support

  mediatek:
   - Add display binding document for MT6795"

* tag 'drm-next-2023-06-29' of git://anongit.freedesktop.org/drm/drm: (1791 commits)
  drm/i915: Fix a NULL vs IS_ERR() bug
  drm/i915: make i915_drm_client_fdinfo() reference conditional again
  drm/i915/huc: Fix missing error code in intel_huc_init()
  drm/i915/gsc: take a wakeref for the proxy-init-completion check
  drm/msm/a6xx: Add A610 speedbin support
  drm/msm/a6xx: Add A619_holi speedbin support
  drm/msm/a6xx: Use adreno_is_aXYZ macros in speedbin matching
  drm/msm/a6xx: Use "else if" in GPU speedbin rev matching
  drm/msm/a6xx: Fix some A619 tunables
  drm/msm/a6xx: Add A610 support
  drm/msm/a6xx: Add support for A619_holi
  drm/msm/adreno: Disable has_cached_coherent in GMU wrapper configurations
  drm/msm/a6xx: Introduce GMU wrapper support
  drm/msm/a6xx: Move CX GMU power counter enablement to hw_init
  drm/msm/a6xx: Extend and explain UBWC config
  drm/msm/a6xx: Remove both GBIF and RBBM GBIF halt on hw init
  drm/msm/a6xx: Add a helper for software-resetting the GPU
  drm/msm/a6xx: Improve a6xx_bus_clear_pending_transactions()
  drm/msm/a6xx: Move a6xx_bus_clear_pending_transactions to a6xx_gpu
  drm/msm/a6xx: Move force keepalive vote removal to a6xx_gmu_force_off()
  ...

Pull non-mm updates from Andrew Morton:

 - Arnd Bergmann has fixed a bunch of -Wmissing-prototypes in top-level
   directories

 - Douglas Anderson has added a new "buddy" mode to the hardlockup
   detector. It permits the detector to work on architectures which
   cannot provide the required interrupts, by having CPUs periodically
   perform checks on other CPUs

 - Zhen Lei has enhanced kexec's ability to support two crash regions

 - Petr Mladek has done a lot of cleanup on the hard lockup detector's
   Kconfig entries

 - And the usual bunch of singleton patches in various places

* tag 'mm-nonmm-stable-2023-06-24-19-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (72 commits)
  kernel/time/posix-stubs.c: remove duplicated include
  ocfs2: remove redundant assignment to variable bit_off
  watchdog/hardlockup: fix typo in config HARDLOCKUP_DETECTOR_PREFER_BUDDY
  powerpc: move arch_trigger_cpumask_backtrace from nmi.h to irq.h
  devres: show which resource was invalid in __devm_ioremap_resource()
  watchdog/hardlockup: define HARDLOCKUP_DETECTOR_ARCH
  watchdog/sparc64: define HARDLOCKUP_DETECTOR_SPARC64
  watchdog/hardlockup: make HAVE_NMI_WATCHDOG sparc64-specific
  watchdog/hardlockup: declare arch_touch_nmi_watchdog() only in linux/nmi.h
  watchdog/hardlockup: make the config checks more straightforward
  watchdog/hardlockup: sort hardlockup detector related config values a logical way
  watchdog/hardlockup: move SMP barriers from common code to buddy code
  watchdog/buddy: simplify the dependency for HARDLOCKUP_DETECTOR_PREFER_BUDDY
  watchdog/buddy: don't copy the cpumask in watchdog_next_cpu()
  watchdog/buddy: cleanup how watchdog_buddy_check_hardlockup() is called
  watchdog/hardlockup: remove softlockup comment in touch_nmi_watchdog()
  watchdog/hardlockup: in watchdog_hardlockup_check() use cpumask_copy()
  watchdog/hardlockup: don't use raw_cpu_ptr() in watchdog_hardlockup_kick()
  watchdog/hardlockup: HAVE_NMI_WATCHDOG must implement watchdog_hardlockup_probe()
  watchdog/hardlockup: keep kernel.nmi_watchdog sysctl as 0444 if probe fails
  ...

Pull locking updates from Ingo Molnar:

 - Introduce cmpxchg128() -- aka. the demise of cmpxchg_double()

   The cmpxchg128() family of functions is basically & functionally the
   same as cmpxchg_double(), but with a saner interface.

   Instead of a 6-parameter horror that forced u128 - u64/u64-halves
   layout details on the interface and exposed users to complexity,
   fragility & bugs, use a natural 3-parameter interface with u128
   types.

 - Restructure the generated atomic headers, and add kerneldoc comments
   for all of the generic atomic{,64,_long}_t operations.

   The generated definitions are much cleaner now, and come with
   documentation.

 - Implement lock_set_cmp_fn() on lockdep, for defining an ordering when
   taking multiple locks of the same type.

   This gets rid of one use of lockdep_set_novalidate_class() in the
   bcache code.

 - Fix raw_cpu_generic_try_cmpxchg() bug due to an unintended variable
   shadowing generating garbage code on Clang on certain ARM builds.

* tag 'locking-core-2023-06-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (43 commits)
  locking/atomic: scripts: fix ${atomic}_dec_if_positive() kerneldoc
  percpu: Fix self-assignment of __old in raw_cpu_generic_try_cmpxchg()
  locking/atomic: treewide: delete arch_atomic_*() kerneldoc
  locking/atomic: docs: Add atomic operations to the driver basic API documentation
  locking/atomic: scripts: generate kerneldoc comments
  docs: scripts: kernel-doc: accept bitwise negation like ~@var
  locking/atomic: scripts: simplify raw_atomic*() definitions
  locking/atomic: scripts: simplify raw_atomic_long*() definitions
  locking/atomic: scripts: split pfx/name/sfx/order
  locking/atomic: scripts: restructure fallback ifdeffery
  locking/atomic: scripts: build raw_atomic_long*() directly
  locking/atomic: treewide: use raw_atomic*_<op>()
  locking/atomic: scripts: add trivial raw_atomic*_<op>()
  locking/atomic: scripts: factor out order template generation
  locking/atomic: scripts: remove leftover "${mult}"
  locking/atomic: scripts: remove bogus order parameter
  locking/atomic: xtensa: add preprocessor symbols
  locking/atomic: x86: add preprocessor symbols
  locking/atomic: sparc: add preprocessor symbols
  locking/atomic: sh: add preprocessor symbols
  ...

arch_touch_nmi_watchdog() needs a different implementation for various
hardlockup detector implementations. And it does nothing when
any hardlockup detector is not built at all.

arch_touch_nmi_watchdog() is declared via linux/nmi.h. And it must be
defined as an empty function when there is no hardlockup detector.
It is done directly in this header file for the perf and buddy detectors.
And it is done in the included asm/linux.h for arch specific detectors.

The reason probably is that the arch specific variants build the code
using another conditions. For example, powerpc64/sparc64 builds the code
when CONFIG_PPC_WATCHDOG is enabled.

Another reason might be that these architectures define more functions
in asm/nmi.h anyway.

However the generic code actually knows when the function will be
implemented. It happens when some full featured or the sparc64-specific
hardlockup detector is built.

In particular, CONFIG_HARDLOCKUP_DETECTOR can be enabled only when
a generic or arch-specific full featured hardlockup detector is available.
The only exception is sparc64 which can be built even when the global
HARDLOCKUP_DETECTOR switch is disabled.

The information about sparc64 is a bit complicated. The hardlockup
detector is built there when CONFIG_HAVE_NMI_WATCHDOG is set and
CONFIG_HAVE_HARDLOCKUP_DETECTOR_ARCH is not set.

People might wonder whether this change really makes things easier.
The motivation is:

  + The current logic in linux/nmi.h is far from obvious.
    For example, arch_touch_nmi_watchdog() is defined as {} when
    neither CONFIG_HARDLOCKUP_DETECTOR_COUNTS_HRTIMER nor
    CONFIG_HAVE_NMI_WATCHDOG is defined.

  + The change synchronizes the checks in lib/Kconfig.debug and
    in the generic code.

  + It is a step that will help cleaning HAVE_NMI_WATCHDOG related
    checks.

The change should not change the existing behavior.

Link: https://lkml.kernel.org/r/20230616150618.6073-4-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

check_bugs() is about to be phased out. Switch over to the new
arch_cpu_finalize_init() implementation.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://lore.kernel.org/r/20230613224545.431995857@linutronix.de

The init/main.c file contains some extern declarations for functions
defined in architecture code, and it defines some other functions that are
called from architecture code with a custom prototype.  Both of those
result in warnings with 'make W=1':

init/calibrate.c:261:37: error: no previous prototype for 'calibrate_delay_is_known' [-Werror=missing-prototypes]
init/main.c:790:20: error: no previous prototype for 'mem_encrypt_init' [-Werror=missing-prototypes]
init/main.c:792:20: error: no previous prototype for 'poking_init' [-Werror=missing-prototypes]
arch/arm64/kernel/irq.c:122:13: error: no previous prototype for 'init_IRQ' [-Werror=missing-prototypes]
arch/arm64/kernel/time.c:55:13: error: no previous prototype for 'time_init' [-Werror=missing-prototypes]
arch/x86/kernel/process.c:935:13: error: no previous prototype for 'arch_post_acpi_subsys_init' [-Werror=missing-prototypes]
init/calibrate.c:261:37: error: no previous prototype for 'calibrate_delay_is_known' [-Werror=missing-prototypes]
kernel/fork.c:991:20: error: no previous prototype for 'arch_task_cache_init' [-Werror=missing-prototypes]

Add prototypes for all of these in include/linux/init.h or another
appropriate header, and remove the duplicate declarations from
architecture specific code.

[sfr@canb.auug.org.au: declare time_init_early()]
  Link: https://lkml.kernel.org/r/20230519124311.5167221c@canb.auug.org.au
Link: https://lkml.kernel.org/r/20230517131102.934196-12-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Some atomics can be implemented in several different ways, e.g.
FULL/ACQUIRE/RELEASE ordered atomics can be implemented in terms of
RELAXED atomics, and ACQUIRE/RELEASE/RELAXED can be implemented in terms
of FULL ordered atomics. Other atomics are optional, and don't exist in
some configurations (e.g. not all architectures implement the 128-bit
cmpxchg ops).

Subsequent patches will require that architectures define a preprocessor
symbol for any atomic (or ordering variant) which is optional. This will
make the fallback ifdeffery more robust, and simplify future changes.

Add the required definitions to arch/sparc.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230605070124.3741859-12-mark.rutland@arm.com

Most architectures define the atomic/atomic64 xchg and cmpxchg
operations in terms of arch_xchg and arch_cmpxchg respectfully.

Add fallbacks for these cases and remove the trivial cases from arch
code. On some architectures the existing definitions are kept as these
are used to build other arch_atomic*() operations.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230605070124.3741859-5-mark.rutland@arm.com