1. 20 Mar, 2023 35 commits
  2. 05 Mar, 2023 5 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