linux-toradex.git/arch/m68k/include, branch master

treewide: provide a generic clear_user_page() variant

2026-01-21T03:24:39+00:00

Patch series "mm: folio_zero_user: clear page ranges", v11.

This series adds clearing of contiguous page ranges for hugepages.

The series improves on the current discontiguous clearing approach in two
ways:

  - clear pages in a contiguous fashion.
  - use batched clearing via clear_pages() wherever exposed.

The first is useful because it allows us to make much better use of
hardware prefetchers.

The second, enables advertising the real extent to the processor.  Where
specific instructions support it (ex.  string instructions on x86; "mops"
on arm64 etc), a processor can optimize based on this because, instead of
seeing a sequence of 8-byte stores, or a sequence of 4KB pages, it sees a
larger unit being operated on.

For instance, AMD Zen uarchs (for extents larger than LLC-size) switch to
a mode where they start eliding cacheline allocation.  This is helpful not
just because it results in higher bandwidth, but also because now the
cache is not evicting useful cachelines and replacing them with zeroes.

Demand faulting a 64GB region shows performance improvement:

 $ perf bench mem mmap -p $pg-sz -f demand -s 64GB -l 5

                       baseline              +series
                   (GBps +- %stdev)      (GBps +- %stdev)

   pg-sz=2MB       11.76 +- 1.10%        25.34 +- 1.18% [*]   +115.47%  	preempt=*

   pg-sz=1GB       24.85 +- 2.41%        39.22 +- 2.32%       + 57.82%  	preempt=none|voluntary
   pg-sz=1GB         (similar)           52.73 +- 0.20% [#]   +112.19%  	preempt=full|lazy

 [*] This improvement is because switching to sequential clearing
  allows the hardware prefetchers to do a much better job.

 [#] For pg-sz=1GB a large part of the improvement is because of the
  cacheline elision mentioned above. preempt=full|lazy improves upon
  that because, not needing explicit invocations of cond_resched() to
  ensure reasonable preemption latency, it can clear the full extent
  as a single unit. In comparison the maximum extent used for
  preempt=none|voluntary is PROCESS_PAGES_NON_PREEMPT_BATCH (32MB).

  When provided the full extent the processor forgoes allocating
  cachelines on this path almost entirely.

  (The hope is that eventually, in the fullness of time, the lazy
   preemption model will be able to do the same job that none or
   voluntary models are used for, allowing us to do away with
   cond_resched().)

Raghavendra also tested previous version of the series on AMD Genoa and
sees similar improvement [1] with preempt=lazy.

  $ perf bench mem map -p $page-size -f populate -s 64GB -l 10

                    base               patched              change
   pg-sz=2MB       12.731939 GB/sec    26.304263 GB/sec     106.6%
   pg-sz=1GB       26.232423 GB/sec    61.174836 GB/sec     133.2%


This patch (of 8):

Let's drop all variants that effectively map to clear_page() and provide
it in a generic variant instead.

We'll use the macro clear_user_page to indicate whether an architecture
provides it's own variant.

Also, clear_user_page() is only called from the generic variant of
clear_user_highpage(), so define it only if the architecture does not
provide a clear_user_highpage().  And, for simplicity define it in
linux/highmem.h.

Note that for parisc, clear_page() and clear_user_page() map to
clear_page_asm(), so we can just get rid of the custom clear_user_page()
implementation.  There is a clear_user_page_asm() function on parisc, that
seems to be unused.  Not sure what's up with that.

Link: https://lkml.kernel.org/r/20260107072009.1615991-1-ankur.a.arora@oracle.com
Link: https://lkml.kernel.org/r/20260107072009.1615991-2-ankur.a.arora@oracle.com
Signed-off-by: David Hildenbrand 
Co-developed-by: Ankur Arora 
Signed-off-by: Ankur Arora 
Cc: Andy Lutomirski 
Cc: Ankur Arora 
Cc: "Borislav Petkov (AMD)" 
Cc: Boris Ostrovsky 
Cc: David Hildenbrand 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Konrad Rzessutek Wilk 
Cc: Lance Yang 
Cc: "Liam R. Howlett" 
Cc: Li Zhe 
Cc: Lorenzo Stoakes 
Cc: Mateusz Guzik 
Cc: Matthew Wilcox (Oracle) 
Cc: Michal Hocko 
Cc: Mike Rapoport 
Cc: Peter Zijlstra 
Cc: Raghavendra K T 
Cc: Suren Baghdasaryan 
Cc: Thomas Gleixner 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

Merge tag 'pull-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2025-10-03T18:37:50+00:00

Pull misc non-vfs updates from Al Viro:
 "Assorted dead code removal around asm/pgtable.h"

* tag 'pull-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  alpha: unobfuscate _PAGE_P() definition
  kill FIRST_USER_PGD_NR
  alpha: get rid of the remnants of BAD_PAGE and friends
  SET_PAGE_DIR() users had been gone since 2.3.12pre1
  PAGE_PTR() had been last used outside of arch/* in 1.1.94
  csky: remove BS check for FAULT_FLAG_ALLOW_RETRY

Merge tag 'for-6.18/block-20250929' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux

2025-10-02T17:16:56+00:00

Pull block updates from Jens Axboe:

 - NVMe pull request via Keith:
     - FC target fixes (Daniel)
     - Authentication fixes and updates (Martin, Chris)
     - Admin controller handling (Kamaljit)
     - Target lockdep assertions (Max)
     - Keep-alive updates for discovery (Alastair)
     - Suspend quirk (Georg)

 - MD pull request via Yu:
     - Add support for a lockless bitmap.

       A key feature for the new bitmap are that the IO fastpath is
       lockless. If a user issues lots of write IO to the same bitmap
       bit in a short time, only the first write has additional overhead
       to update bitmap bit, no additional overhead for the following
       writes.

       By supporting only resync or recover written data, means in the
       case creating new array or replacing with a new disk, there is no
       need to do a full disk resync/recovery.

 - Switch ->getgeo() and ->bios_param() to using struct gendisk rather
   than struct block_device.

 - Rust block changes via Andreas. This series adds configuration via
   configfs and remote completion to the rnull driver. The series also
   includes a set of changes to the rust block device driver API: a few
   cleanup patches, and a few features supporting the rnull changes.

   The series removes the raw buffer formatting logic from
   `kernel::block` and improves the logic available in `kernel::string`
   to support the same use as the removed logic.

 - floppy arch cleanups

 - Reduce the number of dereferencing needed for ublk commands

 - Restrict supported sockets for nbd. Mostly done to eliminate a class
   of issues perpetually reported by syzbot, by using nonsensical socket
   setups.

 - A few s390 dasd block fixes

 - Fix a few issues around atomic writes

 - Improve DMA interation for integrity requests

 - Improve how iovecs are treated with regards to O_DIRECT aligment
   constraints.

   We used to require each segment to adhere to the constraints, now
   only the request as a whole needs to.

 - Clean up and improve p2p support, enabling use of p2p for metadata
   payloads

 - Improve locking of request lookup, using SRCU where appropriate

 - Use page references properly for brd, avoiding very long RCU sections

 - Fix ordering of recursively submitted IOs

 - Clean up and improve updating nr_requests for a live device

 - Various fixes and cleanups

* tag 'for-6.18/block-20250929' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: (164 commits)
  s390/dasd: enforce dma_alignment to ensure proper buffer validation
  s390/dasd: Return BLK_STS_INVAL for EINVAL from do_dasd_request
  ublk: remove redundant zone op check in ublk_setup_iod()
  nvme: Use non zero KATO for persistent discovery connections
  nvmet: add safety check for subsys lock
  nvme-core: use nvme_is_io_ctrl() for I/O controller check
  nvme-core: do ioccsz/iorcsz validation only for I/O controllers
  nvme-core: add method to check for an I/O controller
  blk-cgroup: fix possible deadlock while configuring policy
  blk-mq: fix null-ptr-deref in blk_mq_free_tags() from error path
  blk-mq: Fix more tag iteration function documentation
  selftests: ublk: fix behavior when fio is not installed
  ublk: don't access ublk_queue in ublk_unmap_io()
  ublk: pass ublk_io to __ublk_complete_rq()
  ublk: don't access ublk_queue in ublk_need_complete_req()
  ublk: don't access ublk_queue in ublk_check_commit_and_fetch()
  ublk: don't pass ublk_queue to ublk_fetch()
  ublk: don't access ublk_queue in ublk_config_io_buf()
  ublk: don't access ublk_queue in ublk_check_fetch_buf()
  ublk: pass q_id and tag to __ublk_check_and_get_req()
  ...

Merge tag 'm68k-for-v6.18-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k

2025-09-30T02:05:58+00:00

Pull m68k updates from Geert Uytterhoeven:

  - Fix whitespace in Zorro name macros

  - Fix find_*_bit() signatures

  - defconfig updates

* tag 'm68k-for-v6.18-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k:
  m68k: defconfig: Update defconfigs for v6.17-rc1
  m68k: bitops: Fix find_*_bit() signatures
  zorro: Remove extra whitespace in macro definitions

m68k: bitops: Fix find_*_bit() signatures

2025-09-15T12:30:21+00:00

The function signatures of the m68k-optimized implementations of the
find_{first,next}_{,zero_}bit() helpers do not match the generic
variants.

Fix this by changing all non-pointer inputs and outputs to "unsigned
long", and updating a few local variables.

Reported-by: kernel test robot 
Closes: https://lore.kernel.org/oe-kbuild-all/202509092305.ncd9mzaZ-lkp@intel.com/
Signed-off-by: Geert Uytterhoeven 
Acked-by: "Yury Norov (NVIDIA)" 
Link: https://patch.msgid.link/de6919554fbb4cd1427155c6bafbac8a9df822c8.1757517135.git.geert@linux-m68k.org

PAGE_PTR() had been last used outside of arch/* in 1.1.94

2025-09-13T19:15:07+00:00

.. and in arch/* - circa 2.2.7.

Reviewed-by: Geert Uytterhoeven  # m68k
Acked-by: Geert Uytterhoeven  # m68k
Signed-off-by: Al Viro

m68k: Add __attribute_const__ to ffs()-family implementations

2025-09-08T21:58:51+00:00

While tracking down a problem where constant expressions used by
BUILD_BUG_ON() suddenly stopped working[1], we found that an added static
initializer was convincing the compiler that it couldn't track the state
of the prior statically initialized value. Tracing this down found that
ffs() was used in the initializer macro, but since it wasn't marked with
__attribute__const__, the compiler had to assume the function might
change variable states as a side-effect (which is not true for ffs(),
which provides deterministic math results).

Add missing __attribute_const__ annotations to M68K's implementations
of ffs(), __ffs(), fls(), __fls(), and ffz() functions. These are
pure mathematical functions that always return the same result for
the same input with no side effects, making them eligible for compiler
optimization.

Build tested ARCH=m68k defconfig with GCC m68k-linux-gnu 14.2.0.

Link: https://github.com/KSPP/linux/issues/364 [1]
Reviewed-by: Geert Uytterhoeven 
Acked-by: Geert Uytterhoeven 
Acked-by: Peter Zijlstra (Intel) 
Link: https://lore.kernel.org/r/20250804164417.1612371-11-kees@kernel.org
Signed-off-by: Kees Cook

floppy: Remove unused CROSS_64KB() macro from arch/ code

2025-08-25T20:46:42+00:00

Since the commit 3d86739c6343 ("floppy: always use the track buffer")
the CROSS_64KB() is not used by the driver, remove the leftovers.

Acked-by: Helge Deller  #parisc
Acked-by: Geert Uytterhoeven  # m68k
Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20250825163545.39303-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Jens Axboe

m68k: Replace ASSEMBLY with ASSEMBLER in non-uapi headers

2025-07-06T10:50:50+00:00

While the GCC and Clang compilers already define __ASSEMBLER__
automatically when compiling assembly code, __ASSEMBLY__ is a
macro that only gets defined by the Makefiles in the kernel.
This can be very confusing when switching between userspace
and kernelspace coding, or when dealing with uapi headers that
rather should use __ASSEMBLER__ instead. So let's standardize on
the __ASSEMBLER__ macro that is provided by the compilers now.

This is almost a completely mechanical patch (done with a simple
"sed -i" statement), with one comment tweaked manually in
arch/m68k/include/asm/mac_baboon.h (which was missing underscores).

Signed-off-by: Thomas Huth 
Acked-by: Greg Ungerer 
Reviewed-by: Geert Uytterhoeven 
Link: https://lore.kernel.org/20250611114056.118309-3-thuth@redhat.com
Signed-off-by: Geert Uytterhoeven

m68k: Replace ASSEMBLY with ASSEMBLER in uapi headers