1. Jun 28, 2005
    • David S. Miller's avatar
      [SPARC64]: Avoid membar instructions in delay slots. · b445e26c
      David S. Miller authored
      
      
      In particular, avoid membar instructions in the delay
      slot of a jmpl instruction.
      
      UltraSPARC-I, II, IIi, and IIe have a bug, documented in
      the UltraSPARC-IIi User's Manual, Appendix K, Erratum 51
      
      The long and short of it is that if the IMU unit misses
      on a branch or jmpl, and there is a store buffer synchronizing
      membar in the delay slot, the chip can stop fetching instructions.
      
      If interrupts are enabled or some other trap is enabled, the
      chip will unwedge itself, but performance will suffer.
      
      We already had a workaround for this bug in a few spots, but
      it's better to have the entire tree sanitized for this rule.
      
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      b445e26c
  2. Jun 27, 2005