1. 25 Apr, 2017 2 commits
    • Willem de Bruijn's avatar
      virtio-net: napi helper functions · e4e8452a
      Willem de Bruijn authored
      Prepare virtio-net for tx napi by converting existing napi code to
      use helper functions. This also deduplicates some logic.
      Signed-off-by: default avatarWillem de Bruijn <willemb@google.com>
      Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      e4e8452a
    • David S. Miller's avatar
      sparc64: Improve 64-bit constant loading in eBPF JIT. · 14933dc8
      David S. Miller authored
      Doing a full 64-bit decomposition is really stupid especially for
      simple values like 0 and -1.
      
      But if we are going to optimize this, go all the way and try for all 2
      and 3 instruction sequences not requiring a temporary register as
      well.
      
      First we do the easy cases where it's a zero or sign extended 32-bit
      number (sethi+or, sethi+xor, respectively).
      
      Then we try to find a range of set bits we can load simply then shift
      up into place, in various ways.
      
      Then we try negating the constant and see if we can do a simple
      sequence using that with a xor at the end.  (f.e. the range of set
      bits can't be loaded simply, but for the negated value it can)
      
      The final optimized strategy involves 4 instructions sequences not
      needing a temporary register.
      
      Otherwise we sadly fully decompose using a temp..
      
      Example, from ALU64_XOR_K: 0x0000ffffffff0000 ^ 0x0 = 0x0000ffffffff0000:
      
      0000000000000000 <foo>:
         0:   9d e3 bf 50     save  %sp, -176, %sp
         4:   01 00 00 00     nop
         8:   90 10 00 18     mov  %i0, %o0
         c:   13 3f ff ff     sethi  %hi(0xfffffc00), %o1
        10:   92 12 63 ff     or  %o1, 0x3ff, %o1     ! ffffffff <foo+0xffffffff>
        14:   93 2a 70 10     sllx  %o1, 0x10, %o1
        18:   15 3f ff ff     sethi  %hi(0xfffffc00), %o2
        1c:   94 12 a3 ff     or  %o2, 0x3ff, %o2     ! ffffffff <foo+0xffffffff>
        20:   95 2a b0 10     sllx  %o2, 0x10, %o2
        24:   92 1a 60 00     xor  %o1, 0, %o1
        28:   12 e2 40 8a     cxbe  %o1, %o2, 38 <foo+0x38>
        2c:   9a 10 20 02     mov  2, %o5
        30:   10 60 00 03     b,pn   %xcc, 3c <foo+0x3c>
        34:   01 00 00 00     nop
        38:   9a 10 20 01     mov  1, %o5     ! 1 <foo+0x1>
        3c:   81 c7 e0 08     ret
        40:   91 eb 40 00     restore  %o5, %g0, %o0
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      14933dc8
  2. 24 Apr, 2017 38 commits