On Thu, 26 Nov 2020 18:50:11 +0100 Borislav Petkov <b...@alien8.de> wrote:
> On Thu, Nov 26, 2020 at 10:37:09AM +0900, Masami Hiramatsu wrote: > > BTW, the instruction validation depends on who needs it, because to > > check the all invalid ops, we need more information in the > > x86-opcode-map.txt > > and it will bloat up the table size and consumes more time to analysis. > > Yes, the decoder is supposed to serve the kernel's needs, not be a > general purpose one. > > > (Moreover, it depends on the processor generation -- older processor will > > not support VEX prefix, those are invalid) > > Why does the processor VEX support matter? Isn't the decoder supposed to > decode any instruction it knows about, regardless of the CPU it runs on? Hm, you meant the "invalid" means "that can not be decoded" ? Then it is OK. I Thought "invalid" means "the processor can not execute (some exception will occur)". > > > OK, then could you use -1 instead of 1? It may allow us to expand it > > to return error code in the future. > > Ok, sure. Thanks! > > > I think insn_get_prefixes() can be used independently, because x86 > > perfix bytes is very complex. > > Yah, it all depends on what API interfaces we want to give to users and > make those other helpers internal. Time and usecases will tell. > > Thx. > > -- > Regards/Gruss, > Boris. > > https://people.kernel.org/tglx/notes-about-netiquette -- Masami Hiramatsu <mhira...@kernel.org>
