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  1. 24 Mar, 2023 1 commit
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  13. 05 Mar, 2023 9 commits
    • Linus Torvalds's avatar
      Linux 6.3-rc1 · fe15c26e
      Linus Torvalds authored
      fe15c26e
    • Linus Torvalds's avatar
      cpumask: re-introduce constant-sized cpumask optimizations · 596ff4a0
      Linus Torvalds authored 
      Commit aa47a7c2 ("lib/cpumask: deprecate nr_cpumask_bits") resulted
in the cpumask operations potentially becoming hugely less efficient,
because suddenly the cpumask was always considered to be variable-sized.

The optimization was then later added back in a limited form by commit
6f9c07be ("lib/cpumask: add FORCE_NR_CPUS config option"), but that
FORCE_NR_CPUS option is not useful in a generic kernel and more of a
special case for embedded situations with fixed hardware.

Instead, just re-introduce the optimization, with some changes.

Instead of depending on CPUMASK_OFFSTACK being false, and then always
using the full constant cpumask width, this introduces three different
cpumask "sizes":

 - the exact size (nr_cpumask_bits) remains identical to nr_cpu_ids.

   This is used for situations where we should use the exact size.

 - the "small" size (small_cpumask_bits) is the NR_CPUS constant if it
   fits in a single word and the bitmap operations thus end up able
   to trigger the "small_const_nbits()" optimizations.

   This is used for the operations that have optimized single-word
   cases that get inlined, notably the bit find and scanning functions.

 - the "large" size (large_cpumask_bits) is the NR_CPUS constant if it
   is an sufficiently small constant that makes simple "copy" and
   "clear" operations more efficient.

   This is arbitrarily set at four words or less.

As a an example of this situation, without this fixed size optimization,
cpumask_clear() will generate code like

        movl    nr_cpu_ids(%rip), %edx
        addq    $63, %rdx
        shrq    $3, %rdx
        andl    $-8, %edx
        callq   memset@PLT

on x86-64, because it would calculate the "exact" number of longwords
that need to be cleared.

In contrast, with this patch, using a MAX_CPU of 64 (which is quite a
reasonable value to use), the above becomes a single

	movq $0,cpumask

instruction instead, because instead of caring to figure out exactly how
many CPU's the system has, it just knows that the cpumask will be a
single word and can just clear it all.

Note that this does end up tightening the rules a bit from the original
version in another way: operations that set bits in the cpumask are now
limited to the actual nr_cpu_ids limit, whereas we used to do the
nr_cpumask_bits thing almost everywhere in the cpumask code.

But if you just clear bits, or scan for bits, we can use the simpler
compile-time constants.

In the process, remove 'cpumask_complement()' and 'for_each_cpu_not()'
which were not useful, and which fundamentally have to be limited to
'nr_cpu_ids'.  Better remove them now than have somebody introduce use
of them later.

Of course, on x86-64 with MAXSMP there is no sane small compile-time
constant for the cpumask sizes, and we end up using the actual CPU bits,
and will generate the above kind of horrors regardless.  Please don't
use MAXSMP unless you really expect to have machines with thousands of
cores.
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      596ff4a0
    • Linus Torvalds's avatar
      Merge tag 'v6.3-p2' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 · f915322f
      Linus Torvalds authored 
      Pull crypto fix from Herbert Xu:
 "Fix a regression in the caam driver"

* tag 'v6.3-p2' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: caam - Fix edesc/iv ordering mixup
      f915322f
    • Linus Torvalds's avatar
      Merge tag 'x86-urgent-2023-03-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 7f9ec7d8
      Linus Torvalds authored 
      Pull x86 updates from Thomas Gleixner:
 "A small set of updates for x86:

   - Return -EIO instead of success when the certificate buffer for SEV
     guests is not large enough

   - Allow STIPB to be enabled with legacy IBSR. Legacy IBRS is cleared
     on return to userspace for performance reasons, but the leaves user
     space vulnerable to cross-thread attacks which STIBP prevents.
     Update the documentation accordingly"

* tag 'x86-urgent-2023-03-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  virt/sev-guest: Return -EIO if certificate buffer is not large enough
  Documentation/hw-vuln: Document the interaction between IBRS and STIBP
  x86/speculation: Allow enabling STIBP with legacy IBRS
      7f9ec7d8
    • Linus Torvalds's avatar
      Merge tag 'irq-urgent-2023-03-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 4e9c542c
      Linus Torvalds authored 
      Pull irq updates from Thomas Gleixner:
 "A set of updates for the interrupt susbsystem:

   - Prevent possible NULL pointer derefences in
     irq_data_get_affinity_mask() and irq_domain_create_hierarchy()

   - Take the per device MSI lock before invoking code which relies on
     it being hold

   - Make sure that MSI descriptors are unreferenced before freeing
     them. This was overlooked when the platform MSI code was converted
     to use core infrastructure and results in a fals positive warning

   - Remove dead code in the MSI subsystem

   - Clarify the documentation for pci_msix_free_irq()

   - More kobj_type constification"

* tag 'irq-urgent-2023-03-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq/msi, platform-msi: Ensure that MSI descriptors are unreferenced
  genirq/msi: Drop dead domain name assignment
  irqdomain: Add missing NULL pointer check in irq_domain_create_hierarchy()
  genirq/irqdesc: Make kobj_type structures constant
  PCI/MSI: Clarify usage of pci_msix_free_irq()
  genirq/msi: Take the per-device MSI lock before validating the control structure
  genirq/ipi: Fix NULL pointer deref in irq_data_get_affinity_mask()
      4e9c542c
    • Linus Torvalds's avatar
      Merge tag 'pull-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs · 1a90673e
      Linus Torvalds authored 
      Pull vfs update from Al Viro:
 "Adding Christian Brauner as VFS co-maintainer"

* tag 'pull-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  Adding VFS co-maintainer
      1a90673e
    • Linus Torvalds's avatar
      Merge tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs · 1a8d05a7
      Linus Torvalds authored 
      Pull VM_FAULT_RETRY fixes from Al Viro:
 "Some of the page fault handlers do not deal with the following case
  correctly:

   - handle_mm_fault() has returned VM_FAULT_RETRY

   - there is a pending fatal signal

   - fault had happened in kernel mode

  Correct action in such case is not "return unconditionally" - fatal
  signals are handled only upon return to userland and something like
  copy_to_user() would end up retrying the faulting instruction and
  triggering the same fault again and again.

  What we need to do in such case is to make the caller to treat that as
  failed uaccess attempt - handle exception if there is an exception
  handler for faulting instruction or oops if there isn't one.

  Over the years some architectures had been fixed and now are handling
  that case properly; some still do not. This series should fix the
  remaining ones.

  Status:

   - m68k, riscv, hexagon, parisc: tested/acked by maintainers.

   - alpha, sparc32, sparc64: tested locally - bug has been reproduced
     on the unpatched kernel and verified to be fixed by this series.

   - ia64, microblaze, nios2, openrisc: build, but otherwise completely
     untested"

* tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  openrisc: fix livelock in uaccess
  nios2: fix livelock in uaccess
  microblaze: fix livelock in uaccess
  ia64: fix livelock in uaccess
  sparc: fix livelock in uaccess
  alpha: fix livelock in uaccess
  parisc: fix livelock in uaccess
  hexagon: fix livelock in uaccess
  riscv: fix livelock in uaccess
  m68k: fix livelock in uaccess
      1a8d05a7
    • Masahiro Yamada's avatar
      Remove Intel compiler support · 95207db8
      Masahiro Yamada authored 
      include/linux/compiler-intel.h had no update in the past 3 years.

We often forget about the third C compiler to build the kernel.

For example, commit a0a12c3e ("asm goto: eradicate CC_HAS_ASM_GOTO")
only mentioned GCC and Clang.

init/Kconfig defines CC_IS_GCC and CC_IS_CLANG but not CC_IS_ICC,
and nobody has reported any issue.

I guess the Intel Compiler support is broken, and nobody is caring
about it.

Harald Arnesen pointed out ICC (classic Intel C/C++ compiler) is
deprecated:

    $ icc -v
    icc: remark #10441: The Intel(R) C++ Compiler Classic (ICC) is
    deprecated and will be removed from product release in the second half
    of 2023. The Intel(R) oneAPI DPC++/C++ Compiler (ICX) is the recommended
    compiler moving forward. Please transition to use this compiler. Use
    '-diag-disable=10441' to disable this message.
    icc version 2021.7.0 (gcc version 12.1.0 compatibility)

Arnd Bergmann provided a link to the article, "Intel C/C++ compilers
complete adoption of LLVM".

lib/zstd/common/compiler.h and lib/zstd/compress/zstd_fast.c were kept
untouched for better sync with https://github.com/facebook/zstd

Link: https://www.intel.com/content/www/us/en/developer/articles/technical/adoption-of-llvm-complete-icx.htmlSigned-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
Reviewed-by: default avatarNick Desaulniers <ndesaulniers@google.com>
Reviewed-by: default avatarNathan Chancellor <nathan@kernel.org>
Reviewed-by: default avatarMiguel Ojeda <ojeda@kernel.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      95207db8
    • Al Viro's avatar
      Adding VFS co-maintainer · 3304f18b
      Al Viro authored 
      Acked-by: default avatarChristian Brauner <brauner@kernel.org>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      3304f18b
  15. 04 Mar, 2023 3 commits
    • Linus Torvalds's avatar
      Merge tag 'i2c-for-6.3-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux · b01fe98d
      Linus Torvalds authored 
      Pull more i2c updates from Wolfram Sang:
 "Some improvements/fixes for the newly added GXP driver and a Kconfig
  dependency fix"

* tag 'i2c-for-6.3-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: gxp: fix an error code in probe
  i2c: gxp: return proper error on address NACK
  i2c: gxp: remove "empty" switch statement
  i2c: Disable I2C_APPLE when I2C_PASEMI is a builtin
      b01fe98d
    • Linus Torvalds's avatar
      mm: avoid gcc complaint about pointer casting · e77d587a
      Linus Torvalds authored 
      The migration code ends up temporarily stashing information of the wrong
type in unused fields of the newly allocated destination folio.  That
all works fine, but gcc does complain about the pointer type mis-use:

    mm/migrate.c: In function ‘__migrate_folio_extract’:
    mm/migrate.c:1050:20: note: randstruct: casting between randomized structure pointer types (ssa): ‘struct anon_vma’ and ‘struct address_space’

     1050 |         *anon_vmap = (void *)dst->mapping;
          |         ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

and gcc is actually right to complain since it really doesn't understand
that this is a very temporary special case where this is ok.

This could be fixed in different ways by just obfuscating the assignment
sufficiently that gcc doesn't see what is going on, but the truly
"proper C" way to do this is by explicitly using a union.

Using unions for type conversions like this is normally hugely ugly and
syntactically nasty, but this really is one of the few cases where we
want to make it clear that we're not doing type conversion, we're really
re-using the value bit-for-bit just using another type.

IOW, this should not become a common pattern, but in this one case using
that odd union is probably the best way to document to the compiler what
is conceptually going on here.

[ Side note: there are valid cases where we convert pointers to other
  pointer types, notably the whole "folio vs page" situation, where the
  types actually have fundamental commonalities.

  The fact that the gcc note is limited to just randomized structures
  means that we don't see equivalent warnings for those cases, but it
  migth also mean that we miss other cases where we do play these kinds
  of dodgy games, and this kind of explicit conversion might be a good
  idea. ]

I verified that at least for an allmodconfig build on x86-64, this
generates the exact same code, apart from line numbers and assembler
comment changes.

Fixes: 64c8902e ("migrate_pages: split unmap_and_move() to _unmap() and _move()")
Cc: Huang, Ying <ying.huang@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e77d587a
    • Linus Torvalds's avatar
      Merge tag 'mm-hotfixes-stable-2023-03-04-13-12' of... · 20fdfd55
      Linus Torvalds authored 
      Merge tag 'mm-hotfixes-stable-2023-03-04-13-12' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "17 hotfixes.

  Eight are for MM and seven are for other parts of the kernel. Seven
  are cc:stable and eight address post-6.3 issues or were judged
  unsuitable for -stable backporting"

* tag 'mm-hotfixes-stable-2023-03-04-13-12' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mailmap: map Dikshita Agarwal's old address to his current one
  mailmap: map Vikash Garodia's old address to his current one
  fs/cramfs/inode.c: initialize file_ra_state
  fs: hfsplus: fix UAF issue in hfsplus_put_super
  panic: fix the panic_print NMI backtrace setting
  lib: parser: update documentation for match_NUMBER functions
  kasan, x86: don't rename memintrinsics in uninstrumented files
  kasan: test: fix test for new meminstrinsic instrumentation
  kasan: treat meminstrinsic as builtins in uninstrumented files
  kasan: emit different calls for instrumentable memintrinsics
  ocfs2: fix non-auto defrag path not working issue
  ocfs2: fix defrag path triggering jbd2 ASSERT
  mailmap: map Georgi Djakov's old Linaro address to his current one
  mm/hwpoison: convert TTU_IGNORE_HWPOISON to TTU_HWPOISON
  lib/zlib: DFLTCC deflate does not write all available bits for Z_NO_FLUSH
  mm/damon/paddr: fix missing folio_put()
  mm/mremap: fix dup_anon_vma() in vma_merge() case 4
      20fdfd55
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