Re: Voyager subarchitecture for 2.5.46

Pavel Machek (pavel@ucw.cz)
Sun, 10 Nov 2002 20:18:23 +0100


Hi!

> > Unfortunately, this means "bye bye vsyscalls for gettimeofday".
>
> Not necessarily. All of the fastpatch and the checking can be done by the
> vsyscall, and if the vsyscall notices that there is a backwards jump
> in

I believe you need to *store* last value given to userland. Checking
backwards jump can be dealt with, but to check for time going
backwards you need to *store* result each result of vsyscall. I do not
think that can be done from userlnad.

> That said, I suspect that the real issue with vsyscalls is that they don't
> really make much sense. The only system call we've ever found that matters
> at all is gettimeofday(), and the vsyscall implementation there looks like
> a "cool idea, but doesn't really matter (and complicates things a lot)".

I don't like vsyscalls at all...
Pavel

-- 
When do you have heart between your knees?
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