Messages in this thread | | | Date | Thu, 17 Apr 2014 20:45:29 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH 3/4] x86/insn: Extract more information about instructions |
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On 04/17/2014 08:40 PM, Masami Hiramatsu wrote: > (2014/04/18 2:31), Sasha Levin wrote: >>> I also have seen several attempts at using the generic instruction >>> decoder which has resulted in more complexity, not less, because of >>> excess generality, so it is not an obvious thing. >> >> Let's split this patchset into two: >> >> We have one part which moves kmemcheck to the generic instruction decoder >> and adds memory access size to the instruction decoder. There seems to be >> no objection to that part beyond technical issues regarding how we store >> the new size value. > > This looks OK to me. > >> The other part is adding mnemonics to the instruction decoder. If my >> explanation above makes sense, and kmemcheck does need to know about AND, >> OR, XOR, MOVS and CMPS then let me know how to proceed about changing >> the instruction decoder to add that functionality. > > I don't think we need to add such things to instruction decoder. > You'd better start from clarifying the bit pattern of those instructions > and making macros or inlines which evaluate insn->opcode.value. > > Using automatic generated macros for immediate in the source code always > leads misunderstanding and abuse, and is hard to fix if a bug is there. > I strongly recommend you to define instruction classification macros > for their use by hand. That's easy to review too. > Actually x86 has a long history and its mnemonics are not so simple... >
What it sounds like it really wants is a "bitwise" flag on the instruction.
-hpa
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