Re: [PATCH -tip 3/6 V4.1] x86: instruction decorder API

From: Jim Keniston
Date: Thu Apr 23 2009 - 18:23:24 EST


On Thu, 2009-04-23 at 13:29 -0400, Masami Hiramatsu wrote:
...
>
> Hmm, maybe, parser can handle "(extra_info)" as a solid keyword.
> so let's define actual format.
>
> <opcode maps>
> Table: table-name
> Referrer: escamed-name
> opcode: mnemonic|Grp [operand1[,operand2...]] [(extra1)[,(extra2)...] [| 2nd-mnemonic ...]
> opcode: ESC # escaped-name
>
> <group maps>
> reg: mnemonic ...

For some instruction groups -- e.g., Groups 12, 13, 14 -- the
instruction prefix (66, f2, f3) and the reg field both affect the
instruction type. And for some x87 instructions, the value of the modrm
byte's rm field also affects the instruction type. (For others, rm just
selects among the st(0)..st(7) registers, as one might expect.)

Of course, that's all about floating-point instructions, which are of
more interest to uprobes than kprobes.

Jim

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