Re: [PATCH v3 2/4] xen: change <asm/bug.h> to <xen/bug.h>

[Oleksii <oleksii.kurochko@xxxxxxxxx>]

On Mon, 2023-02-27 at 15:29 +0100, Jan Beulich wrote:
> On 24.02.2023 12:31, Oleksii Kurochko wrote:
> > Since the generic version of bug.h stuff was introduced use
> > <xen/bug.h>
> > instead of unnecessary <asm/bug.h>
> 
> You keep saying "unnecessary" here, but that's not really correct.
> Including asm/bug.h alone simply becomes meaningless. So how about
> "... instead of now useless (in isolation) <asm/bug.h>"?
> 
> > --- a/xen/arch/x86/include/asm/bug.h
> > +++ b/xen/arch/x86/include/asm/bug.h
> > @@ -1,19 +1,10 @@
> >  #ifndef __X86_BUG_H__
> >  #define __X86_BUG_H__
> >  
> > -#define BUG_DISP_WIDTH    24
> > -#define BUG_LINE_LO_WIDTH (31 - BUG_DISP_WIDTH)
> > -#define BUG_LINE_HI_WIDTH (31 - BUG_DISP_WIDTH)
> > -
> > -#define BUGFRAME_run_fn 0
> > -#define BUGFRAME_warn   1
> > -#define BUGFRAME_bug    2
> > -#define BUGFRAME_assert 3
> > -
> > -#define BUGFRAME_NR     4
> > -
> >  #ifndef __ASSEMBLY__
> >  
> > +#define BUG_FRAME_STRUCT
> > +
> >  struct bug_frame {
> >      signed int loc_disp:BUG_DISP_WIDTH;
> >      unsigned int line_hi:BUG_LINE_HI_WIDTH;
> 
> Why would x86 continue to define its own bug_frame (and other items)?
> 
Because x86 will be switched to generic one in the following patches of
the patch series and right now it defines only BUG_FRAME_STRUCT which
means that it will not use generic one implemetation now.
The idea of the patch was to rename <asm/bug.h> to <xen/bug.h> with
minimal required changes to keep Xen compilable.

And I am going to back:

-#define BUG_DISP_WIDTH    24
-#define BUG_LINE_LO_WIDTH (31 - BUG_DISP_WIDTH)
-#define BUG_LINE_HI_WIDTH (31 - BUG_DISP_WIDTH)

for the same reason as in ARM. these defines are related to 'stuct
bug_frame' so should go with it.
These defines will be removed when an architecture will be switched to
generic implementation.

> Jan
~ Oleksii