On Tue, Dec 23, 2014 at 1:19 AM, Ingo Molnar <[email protected]> wrote: > > * Andy Lutomirski <[email protected]> wrote: > >> On Mon, Dec 22, 2014 at 12:21 PM, Dave Hansen <[email protected]> wrote: >> > On 12/22/2014 12:17 PM, Andy Lutomirski wrote: >> >>> > /* >> >>> > + * 32-bit binaries on 64-bit kernels are currently >> >>> > + * unsupported. >> >>> > + */ >> >>> > + if (IS_ENABLED(CONFIG_X86_64) && test_thread_flag(TIF_IA32)) >> >>> > + return MPX_INVALID_BOUNDS_DIR; >> >> Should this check mm->ia32_compat instead? >> > >> > set_personality_64bit/ia32() seem to make that and TIF_IA32 awfully >> > equivalent. Is there a specific reason for wanting it done this way? >> >> My general desire to remove various bogus TIF_IA32 references. >> [...] > > So we generally want to use mm->context.ia32_compat instead of > TIF_IA32, because in the end TIF_IA32 will go away altogether? > > Or do you just want to audit all TIF_IA32 places (because most of > them are wrong), and using mm->context.ia32_compat where it's > justified and eliminating TIF_IA32 use is a nice way to document > that ongoing audit without breaking stuff and such?
TBH, I haven't gotten that far. But of the uses I've looked at, most seem to want TS_COMPAT instead (is_ia32_task, which is IMO terribly named), some are so buggier than just using a strange flag, and I suspect that the rest would make more sense using mm->context.ia32_compat. I was planning on sending some patches to incrementally improve the situation and then seeing where we end up. > >> [...] But this is only temporary, so I don't really care. > > New code that touches this area should better use new principles, > so I have no problem with requiring this, as long as it's well > explained and logical and desirable to everyone. > Given that this patch is a fix for 3.19, the code looks correct, and the check will go away in 3.20, I see no reason to worry about this particular patch. --Andy > Thanks, > > Ingo -- Andy Lutomirski AMA Capital Management, LLC -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
