On Sun, 2017-04-30 at 19:15 +0200, Borislav Petkov wrote: > On Wed, Apr 26, 2017 at 01:44:43PM -0700, Ricardo Neri wrote: > > I regard that the role of this function is to obtain the the segment > > selector from either of the prefixes or inferred from the operands. It > > is the role of caller to determine if the segment selector should be > > ignored. > > No, this is wrong. The function is called resolve_seg_selector() and it > gives you the segment selector. CS, DS, ES, and SS in 64-bit mode are > treated as null segments and your function should return/signal exactly > that, i.e, saying that those should be ignored in that case. > > > I double-checked the latest version of the Intel Software Development > > manual [2], in the table 3-5 in section 3.7.4 mentions that DS is > > default segment for all data references, except string destinations. I > > tested this code with the UMIP-protected instructions and whenever I use > > %edi the default segment is %ds. > > Yes, all correct. Except that we're adding a more-or-less generic x86 > insn decoder so we should make it so... > > > Is this example valid? The documentation of MOVS specifies that it > > always moves DS:(E)SI to ES:(E)DI. > > ... that the decoder should do exactly that: > > if (MOVS and rDI) > return SEG_ES; > > And you're handing in struct insn * so you can easily check which insn > you're looking at. I see. I have submitted v7 of the series and I have implemented all the changes above. Now I am able to identify string instructions. Thanks and BR, Ricardo -- To unsubscribe from this list: send the line "unsubscribe linux-msdos" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
