1. 03 Dec, 2020 11 commits
  2. 26 Nov, 2020 7 commits
  3. 25 Nov, 2020 1 commit
  4. 23 Nov, 2020 2 commits
    • Stephen Rothwell's avatar
      powerpc/64s: Fix allnoconfig build since uaccess flush · b6b79dd5
      Stephen Rothwell authored
      Using DECLARE_STATIC_KEY_FALSE needs linux/jump_table.h.
      
      Otherwise the build fails with eg:
      
        arch/powerpc/include/asm/book3s/64/kup-radix.h:66:1: warning: data definition has no type or storage class
           66 | DECLARE_STATIC_KEY_FALSE(uaccess_flush_key);
      
      Fixes: 9a32a7e7 ("powerpc/64s: flush L1D after user accesses")
      Signed-off-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
      [mpe: Massage change log]
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      Link: https://lore.kernel.org/r/20201123184016.693fe464@canb.auug.org.au
      b6b79dd5
    • Michael Ellerman's avatar
      Merge tag 'powerpc-cve-2020-4788' into fixes · 962f8e64
      Michael Ellerman authored
      From Daniel's cover letter:
      
      IBM Power9 processors can speculatively operate on data in the L1 cache
      before it has been completely validated, via a way-prediction mechanism. It
      is not possible for an attacker to determine the contents of impermissible
      memory using this method, since these systems implement a combination of
      hardware and software security measures to prevent scenarios where
      protected data could be leaked.
      
      However these measures don't address the scenario where an attacker induces
      the operating system to speculatively execute instructions using data that
      the attacker controls. This can be used for example to speculatively bypass
      "kernel user access prevention" techniques, as discovered by Anthony
      Steinhauser of Google's Safeside Project. This is not an attack by itself,
      but there is a possibility it could be used in conjunction with
      side-channels or other weaknesses in the privileged code to construct an
      attack.
      
      This issue can be mitigated by flushing the L1 cache between privilege
      boundaries of concern.
      
      This patch series flushes the L1 cache on kernel entry (patch 2) and after the
      kernel performs any user accesses (patch 3). It also adds a self-test and
      performs some related cleanups.
      962f8e64
  5. 19 Nov, 2020 19 commits