Re: [PATCH 1/3] ia64: convert to use clocksource code

[Peter Keilty]

Daniel Walker wrote:

> On Fri, 2007-04-27 at 10:38 -0400, Peter Keilty wrote:
>  
>
> > Daniel Walker wrote:
> >
> >    
> >
> > > On Thu, 2007-04-26 at 16:26 -0400, Peter Keilty wrote:
> > >
> > >
> > >
> > >      
> > >
> > > > +        .mask           = (1LL << 40) - 1,
> > > > +        .mult           = 0, /*to be caluclated*/
> > > > +        .shift          = 16,
> > > > +        .is_continuous  = 1,
> > > > };
> > > >   
> > > >
> > > >        
> > > You should use CLOCKSOURCE_MASK() here ..
> > >
> > >
> > >
> > >      
> > It is correct in patch 3, I believe.
> >    
>
> There's another spot that should use CLOCKSOURE_MASK() in the hpet I
> think .
>  
Correct that was change in patch 3 also.

>  
>
> > >      
> > >
> > > > diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
> > > > index daa4940..a20b4d6 100644
> > > > --- a/include/linux/clocksource.h
> > > > +++ b/include/linux/clocksource.h
> > > > @@ -61,6 +61,9 @@ struct clocksource {
> > > > 	u32 shift;
> > > > 	unsigned long flags;
> > > > 	cycle_t (*vread)(void);
> > > > +#ifdef CONFIG_IA64
> > > > +	void *fsys_mmio_ptr;	/* used by fsyscall asm code */
> > > > +#endif
> > > >   
> > > >
> > > >        
> > > Could you explain in detail why this is needed?
> > >
> > >
> > >      
> > This ptr is needed to hold the mmio address to read the cycle value.
> > The fast ia64 path utilizies a special gate page which can allow user
> > code to execute small amount of kernel code, normal calling a function
> > not done and so the address is need. The fast syscall path executes on
> > user stack, between user/kernel state. And if the the fast path has to 
> > fallback
> > to the slow syscall code the vread will be needed and used.
> >    
>
> There is a read(), and a vread() did you modify the slow syscall path to
> use the vread()?
>  
I miss type, read().

> Daniel
>
>  
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