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    SubjectRe: [PATCH 3.19 v2 2/3] x86, mpx: Short-circuit the instruction decoder for unexpected opcodes
    Couple of typos...

    On 01/12/2015 03:04 PM, Andy Lutomirski wrote:
    > + /*
    > + * We only _really_ need to decode bndcl/bndcn/bndcu
    > + * Error out on anything else. Check this before decoding the
    > + * instruction to reduce our exposure to intentionally bad code
    > + * to some extent. Note that this shortcut cat incorrectly return

    "...can incorrectly return"

    > + * -EINVAL instead of -EFAULT under some circumstances. This
    > + * discrepency has no effect.
    > + */

    ^^ discrepancy


    > + if (nr_copied < 2)
    > + goto bad_opcode;
    > + if (buf[0] != 0x0f)
    > + goto bad_opcode;
    > + if (buf[1] != 0x1a && buf[1] != 0x1b)
    > + goto bad_opcode;
    ...
    > - /*
    > - * We only _really_ need to decode bndcl/bndcn/bndcu
    > - * Error out on anything else.
    > - */
    > - if (insn->opcode.bytes[0] != 0x0f)
    > - goto bad_opcode;
    > - if ((insn->opcode.bytes[1] != 0x1a) &&
    > - (insn->opcode.bytes[1] != 0x1b))
    > - goto bad_opcode;

    Otherwise, this looks OK to me. Have you tested this at all? I know
    you don't have any MPX hardware, but you can still hack something in to
    point the instruction decoder at an MPX binary.


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