Re: [PATCH v2] x86/boot: Fix include paths for 32bit objects

["Roger Pau Monné" <roger.pau@citrix.com>]

On Tue, Sep 03, 2024 at 02:01:45PM +0100, Andrew Cooper wrote:
> On 03/09/2024 1:43 pm, Roger Pau Monné wrote:
> > On Tue, Sep 03, 2024 at 12:53:34PM +0100, Andrew Cooper wrote:
> >> Most of Xen is build using -nostdinc and a fully specified include path.
> >> However, the makefile line:
> >>
> >>   $(head-bin-objs): XEN_CFLAGS := $(CFLAGS_x86_32) -fpic
> >>
> >> discards XEN_CFLAGS and replaces them with CFLAGS_x86_32.
> >>
> >> Reinstate -nostdinc, and copy all -I (and -Wa,-I) arguments from XEN_CFLAGS.
> >>
> >> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> > I wouldn't mind if you also open-coded the config.h -include addition
> > to CFLAGS_x86_32, regardless:
> >
> > Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
> 
> Thanks.
> 
> TBH, I'm going to put it in as is and unblock the fixes behind it.
> 
> We can adjust the others in due course.

Sure, if that allows you to unblock the rest.

> Given the other shuffling of headers we've done recently, I'm starting
> to think that the -include isn't really as needed as it might once have
> been.
> 
> > I do wonder however whether the explicit assembler includes parameters
> > (-Wa,-I) are actually required, seeing as we only provide include/ to
> > the assembler, but not the arch-specific include paths.
> >
> > This is from XSA-254, which used the '.include' asm directive, but
> > that was ultimately removed by:
> >
> > 762c3890c89f x86: fold indirect_thunk_asm.h into asm-defns.h
> >
> > So maybe the -Wa,-I is no longer needed?
> 
> Perhaps, although I'm struggling to find where it's declared today.

It's in xen/arch/x86/arch.mk.

Thanks, Roger.