Re: [PATCH RFC WIP] x86/paravirt: add register-saving thunks to reducecaller register pressure

[Jeremy Fitzhardinge]

Pavel Machek wrote:
> > This patch seeks to alleviate this pressure by introducing wrapper
> > thunks that will do the register saving/restoring, so that the
> > callsite doesn't need to worry about it, but the callee function can
> > be conventional compiler-generated code.  In many cases (particularly
> > performance-sensitive cases) the callee will be in assembler anyway,
> > and need not use the compiler's calling convention.
> >
> > Standard calling convention is:
> > 	 arguments	    return	scratch
> > x86-32	 eax edx ecx	    eax		?
> >     
>
> esi edi ebp ?
>   

Those are callee-save, so the caller doesn't need to worry about 
preserving their values.

> actually standard calling convention is all arguments on stack iirc
> but we use regparm=3 for kernel...?
>   

Yes.  "standard" = "standard kernel calling convention"


   J
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