On 01/12/2015 03:57 PM, Andy Lutomirski wrote: >>> >> - /* >>> >> - * 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. > I haven't tested this at all. ISTM it's more likely that any test > hack I write for this will mask any problem than that it will be a > real test.
This is completely and totally broken when there is an instruction prefix. Instruction prefixes which occur before the opcodes in the buffer, so buf[0] is not necessarily insn->opcode.bytes[0]. This was immediately obvious when I actually ran this code for the first time, even on hardware without MPX. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
