Messages in this thread | | | Date | Sun, 15 Dec 2002 23:01:32 +0100 | From | Pavel Machek <> | Subject | Re: Intel P6 vs P7 system call performance |
| |
Hi!
> > As far as I know, though, the SYSENTER patch didn't deal with several of > > the corner cases introduced by the generally weird SYSENTER instruction > > (such as the fact that V86 tasks can execute it despite the fact there > > is in general no way to resume execution of the V86 task afterwards.) > > > > In practice this means that vsyscalls is pretty much the only sensible > > way to do this. Also note that INT 80h will need to be supported > > indefinitely. > > > > Personally, I wonder if it's worth the trouble, when x86-64 takes care > > of the issue anyway :) > > There is another way: > > Have apps enter kernel mode via Intel's purposely undefined > instruction, plus a few bytes of padding and identification. > Require that this not cross a page boundry. When it faults, > write the SYSENTER, INT 0x80, or SYSCALL as needed. Leave > the page marked clean so it doesn't need to hit swap; if it > gets paged in again it gets patched again.
Thats *very* dirty hack. vsyscalls seem cleaner than that. Pavel -- Worst form of spam? Adding advertisment signatures ala sourceforge.net. What goes next? Inserting advertisment *into* email? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |