Re: use of setjmp/longjmp in x86 emulator.

[Avi Kivity]

On 03/02/2010 10:49 AM, Gleb Natapov wrote:
> On Mon, Mar 01, 2010 at 02:56:59PM -0800, H. Peter Anvin wrote:
>    
> > On 03/01/2010 02:31 PM, H. Peter Anvin wrote:
> >      
> > > On 03/01/2010 11:18 AM, Zachary Amsden wrote:
> > >        
> > > > It's going to be ugly to emulate segmentation, NX and write protect
> > > > support without hardware to do this checking for you, but it's just what
> > > > you have to do in this slow path - tedious, fully specified emulation.
> > > >
> > > > Just because it's tedious doesn't mean we need to use setjmp / longjmp.
> > > > Throw / catch might be effective, but it's still pretty bizarre to do
> > > > tricks like that in C.
> > > >
> > > >          
> > > Well, setjmp/longjmp really is not much more than exception handling in C.
> > >
> > >        
> > For what it's worth, I think that setjmp/longjmp is not anywhere near as
> > dangerous as people want to make it out to be.  gcc will warn for
> > dangerous uses (and a lot of non-dangerous uses), but generally the
> > difficult problems can be dealt with by moving the setjmp-protected code
> > into a separate function.
> >
> >      
> Can I consider this as ACK for something like the patch blow? :) (with
> proper x86 version of setjmp/longjmp of course).
>    

The setjmp/longjmp implementation should definitely live in arch/*/lib, 
even if kvm is the only user.

--
error compiling committee.c: too many arguments to function

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