On Mon, Jul 27, 2015 at 4:46 PM, H. Peter Anvin <[email protected]> wrote: > Sure, but that is different than getting rid of the _ex forms. >
If we did that and got rid of the _ex forms, though, then the code that matters (the no-fault case) would just be a bunch of movs, right? That's basically the same as the current _ex code. --Andy > On July 27, 2015 4:36:26 PM PDT, Andy Lutomirski <[email protected]> > wrote: >> >> On Mon, Jul 27, 2015 at 4:22 PM, H. Peter Anvin <[email protected]> wrote: >>> >>> For that to work, gcc would have to know about the extable. >> >> >> It could, I think: >> >> asm goto ( >> "1: mov ...\n\t" >> _ASM_EXTABLE(1b, %l2) /* or whatever index it is */ >> : ... : ... : ... : efault); >> >> return 0; >> >> efault: >> return -EFAULT; >> >> I think that wrmsr_safe could get this treatment with current GCC. >> put_user plausibly could, too, if we were willing to mark it volatile >> and accept that we're lying a little bit about the lack of an output >> constraint. get_user would need GCC to understand output constraints >> for real. >> >> --Andy > > > -- > Sent from my Android device with K-9 Mail. Please excuse my brevity. -- 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/
