Re: [PATCH v3 1/5] xen: define ACPI and DT device info sections macros

[oleksii.kurochko@xxxxxxxxx]

On Thu, 2024-09-26 at 08:23 +0200, Jan Beulich wrote:
> On 25.09.2024 18:08, oleksii.kurochko@xxxxxxxxx wrote:
> > On Wed, 2024-09-25 at 10:36 +0200, Jan Beulich wrote:
> > > PPC's desire to use DECL_SECTION() can certainly be covered by
> > > providing
> > > a (trivial) DECL_SECTION() also for Arm and RISC-V. Seeing that
> > > even
> > > x86
> > > overrides the default to the trivial form for building xen.efi,
> > > I'm
> > > inclined to suggest we should actually have a way for an arch to
> > > indicate
> > > to xen.lds.h that it wants just the trivial form (avoiding a
> > > later
> > > #undef).
> > If to go with what I suggested before then x86 will look like:
> > 
> > diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
> > index d48de67cfd..911585541e 100644
> > --- a/xen/arch/x86/xen.lds.S
> > +++ b/xen/arch/x86/xen.lds.S
> > @@ -3,6 +3,10 @@
> >  
> >  #include <xen/cache.h>
> >  #include <xen/lib.h>
> > +
> > +#ifdef EFI
> > +#define SIMPLE_DECL_SECTION
> > +#endif
> >  #include <xen/xen.lds.h>
> >  #include <asm/page.h>
> >  #undef ENTRY
> > @@ -12,9 +16,7 @@
> >  
> >  #define FORMAT "pei-x86-64"
> >  #undef __XEN_VIRT_START
> > -#undef DECL_SECTION
> >  #define __XEN_VIRT_START __image_base__
> > -#define DECL_SECTION(x) x :
> >  
> >  ENTRY(efi_start)
> >  
> > diff --git a/xen/include/xen/xen.lds.h b/xen/include/xen/xen.lds.h
> > index a17810bb28..fb11ba7357 100644
> > --- a/xen/include/xen/xen.lds.h
> > +++ b/xen/include/xen/xen.lds.h
> > @@ -5,6 +5,8 @@
> >   * Common macros to be used in architecture specific linker
> > scripts.
> >   */
> >  
> > +#ifdef SIMPLE_DECL_SECTION
> 
> #ifndef I guess?
> 
> > @@ -15,6 +17,10 @@
> >  # define DECL_SECTION(x) x : AT(ADDR(x) - __XEN_VIRT_START)
> >  #endif
> >  
> > +#else /* SIMPLE_DECL_SECION */
> > +# define DECL_SECTION(x) x :
> > +#endif
> > +
> >  /*
> >   * To avoid any confusion, please note that the EFI macro does not
> > correspond
> >   * to EFI support and is used when linking a native EFI (i.e.
> > PE/COFF)
> > binary,
> > 
> > Does it make sense? Or it would be better to follow way for each
> > architecture:
> >    #undef DECL_SECTION
> >    #define DECL_SECTION(x) x :
> 
> Hard to tell which one's better; I was asking myself that same
> question
> when writing an earlier reply. I'm slightly in favor of the form you
> have
> now.
Do you mean moving only a content of section without secname and laddr
( in case of x86 and PPC ), and alignment to xen.lds.h ?

~ Oleksii