1. 05 5月, 2014 14 次提交
  2. 03 5月, 2014 12 次提交
  3. 01 5月, 2014 5 次提交
  4. 30 4月, 2014 6 次提交
  5. 28 4月, 2014 3 次提交
    • G
      Merge 3.15-rc3 into staging-next · 37aa4836
      Greg Kroah-Hartman 提交于
      37aa4836
    • L
      Linux 3.15-rc3 · d1db0eea
      Linus Torvalds 提交于
      d1db0eea
    • W
      word-at-a-time: avoid undefined behaviour in zero_bytemask macro · ec6931b2
      Will Deacon 提交于
      The asm-generic, big-endian version of zero_bytemask creates a mask of
      bytes preceding the first zero-byte by left shifting ~0ul based on the
      position of the first zero byte.
      
      Unfortunately, if the first (top) byte is zero, the output of
      prep_zero_mask has only the top bit set, resulting in undefined C
      behaviour as we shift left by an amount equal to the width of the type.
      As it happens, GCC doesn't manage to spot this through the call to fls(),
      but the issue remains if architectures choose to implement their shift
      instructions differently.
      
      An example would be arch/arm/ (AArch32), where LSL Rd, Rn, #32 results
      in Rd == 0x0, whilst on arch/arm64 (AArch64) LSL Xd, Xn, #64 results in
      Xd == Xn.
      
      Rather than check explicitly for the problematic shift, this patch adds
      an extra shift by 1, replacing fls with __fls. Since zero_bytemask is
      never called with a zero argument (has_zero() is used to check the data
      first), we don't need to worry about calling __fls(0), which is
      undefined.
      
      Cc: <stable@vger.kernel.org>
      Cc: Victor Kamensky <victor.kamensky@linaro.org>
      Signed-off-by: NWill Deacon <will.deacon@arm.com>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      ec6931b2