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    Revert: "ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS" · adab66b7
    Steven Rostedt (VMware) 提交于
    It was believed that metag was the only architecture that required the ring
    buffer to keep 8 byte words aligned on 8 byte architectures, and with its
    removal, it was assumed that the ring buffer code did not need to handle
    this case. It appears that sparc64 also requires this.
    
    The following was reported on a sparc64 boot up:
    
       kernel: futex hash table entries: 65536 (order: 9, 4194304 bytes, linear)
       kernel: Running postponed tracer tests:
       kernel: Testing tracer function:
       kernel: Kernel unaligned access at TPC[552a20] trace_function+0x40/0x140
       kernel: Kernel unaligned access at TPC[552a24] trace_function+0x44/0x140
       kernel: Kernel unaligned access at TPC[552a20] trace_function+0x40/0x140
       kernel: Kernel unaligned access at TPC[552a24] trace_function+0x44/0x140
       kernel: Kernel unaligned access at TPC[552a20] trace_function+0x40/0x140
       kernel: PASSED
    
    Need to put back the 64BIT aligned code for the ring buffer.
    
    Link: https://lore.kernel.org/r/CADxRZqzXQRYgKc=y-KV=S_yHL+Y8Ay2mh5ezeZUnpRvg+syWKw@mail.gmail.com
    
    Cc: stable@vger.kernel.org
    Fixes: 86b3de60 ("ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS")
    Reported-by: NAnatoly Pugachev <matorola@gmail.com>
    Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
    adab66b7
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