Re: [PATCH v1] xen/config.h: Move BITS_PER_* definitions from asm/config.h to xen/config.h

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

On 3/27/25 2:16 PM, Jan Beulich wrote:

> On 27.03.2025 13:50, Oleksii Kurochko wrote:
> > On 3/27/25 1:44 AM, Andrew Cooper wrote:
> > > On 26/03/2025 5:47 pm, Oleksii Kurochko wrote:
> > > > diff --git a/xen/include/xen/config.h b/xen/include/xen/config.h
> > > > index d888b2314d..dbbf2fce62 100644
> > > > --- a/xen/include/xen/config.h
> > > > +++ b/xen/include/xen/config.h
> > > > @@ -98,4 +98,13 @@
> > > >   #define ZERO_BLOCK_PTR ((void *)-1L)
> > > >   #endif
> > > >   
> > > > +#define BYTES_PER_LONG  __SIZEOF_LONG__
> > > > +
> > > > +#define BITS_PER_BYTE   __CHAR_BIT__
> > > > +#define BITS_PER_INT    (__SIZEOF_INT__ << 3)
> > > > +#define BITS_PER_LONG   (BYTES_PER_LONG << 3)
> > > > +#define BITS_PER_LLONG  (__SIZEOF_LONG_LONG__ << 3)
> > > > +
> > > > +#define POINTER_ALIGN   __SIZEOF_POINTER__
> > > >           
> > > See how much nicer this is.  This patch possibly wants to wait until
> > > I've fixed the compiler checks to update to the new baseline, or we can
> > > just say that staging is staging and corner case error messages are fine.
> > >         
> > Do you mean this patch:https://lore.kernel.org/xen-devel/20250320153241.43809-3-andrew.cooper3@xxxxxxxxxx/?
> >
> > I haven't checked clang but if to look at gcc then these builtin macros was introduced in
> > 024a85aeb6a("c-cppbuiltin.c (builtin_define_type_sizeof): New function.") and it seems like even older then gcc5
> > contains this patch:
> > $ git tag --contains 024a85aeb6a912811d917f737eaad39140c2fb0c
> >    ...
> >    releases/gcc-4.3.0
> >    ...
> >
> > Am I missing something?
> >       
> The check yet to be adjusted is looking for 4.1, so 4.3 would already be "too new".
>     
I guess you mean this one check:
  check-$(gcc) = $(call cc-ver-check,CC,0x040100,"Xen requires at least gcc-4.1")

Could I ask then why in the link above it is checked different version?
-#if !defined(__GNUC__) || (__GNUC__ < 4)
-#error Sorry, your compiler is too old/not recognized.
-#elif CONFIG_CC_IS_GCC
-# if defined(CONFIG_ARM_32) && CONFIG_GCC_VERSION < 40900
-#  error Sorry, your version of GCC is too old - please use 4.9 or newer.
-# elif defined(CONFIG_ARM_64) && CONFIG_GCC_VERSION < 50100
-/*
- * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63293
- * https://lore.kernel.org/r/20210107111841.GN1551@xxxxxxxxxxxxxxxxxxxxx
- */
-#  error Sorry, your version of GCC is too old - please use 5.1 or newer.
-# endif

~ Oleksii