Re: [PATCH v12 7/8] xen/riscv: enable full Xen build

["Oleksii K." <oleksii.kurochko@xxxxxxxxx>]

On Thu, 2024-05-30 at 17:48 +0100, Andrew Cooper wrote:
> On 29/05/2024 8:55 pm, Oleksii Kurochko wrote:
> > diff --git a/xen/arch/riscv/stubs.c b/xen/arch/riscv/stubs.c
> > index 8285bcffef..bda35fc347 100644
> > --- a/xen/arch/riscv/stubs.c
> > +++ b/xen/arch/riscv/stubs.c
> > @@ -24,12 +24,6 @@ DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t,
> > cpu_core_mask);
> >  
> >  nodemask_t __read_mostly node_online_map = { { [0] = 1UL } };
> >  
> > -/*
> > - * max_page is defined in page_alloc.c which isn't complied for
> > now.
> > - * definition of max_page will be remove as soon as page_alloc is
> > built.
> > - */
> > -unsigned long __read_mostly max_page;
> > -
> >  /* time.c */
> >  
> >  unsigned long __ro_after_init cpu_khz;  /* CPU clock frequency in
> > kHz. */
> > @@ -419,21 +413,3 @@ void __cpu_die(unsigned int cpu)
> >  {
> >      BUG_ON("unimplemented");
> >  }
> > -
> > -/*
> > - * The following functions are defined in common/irq.c, but
> > common/irq.c isn't
> > - * built for now. These changes will be removed there when
> > common/irq.c is
> > - * ready.
> > - */
> > -
> > -void cf_check irq_actor_none(struct irq_desc *desc)
> > -{
> > -    BUG_ON("unimplemented");
> > -}
> > -
> > -unsigned int cf_check irq_startup_none(struct irq_desc *desc)
> > -{
> > -    BUG_ON("unimplemented");
> > -
> > -    return 0;
> > -}
> 
> All 3 of these are introduced in the previous patch and deleted again
> here.  Looks like a rebasing accident.
Not really.

This was done to avoid build failures for RISC-V. If the HEAD is on the
previous patch where these changes are introduced and then we just drop
them, it will lead to a linkage error because these functions are
defined in common/irq.c, which isn't built for RISC-V if the HEAD is on
the previous patch:
   /build/xen/arch/riscv/entry.S:86: undefined reference to `max_page'
   riscv64-linux-gnu-ld: prelink.o:(.rodata+0x8): undefined reference to
   `irq_startup_none'
   riscv64-linux-gnu-ld: prelink.o:(.rodata+0x10): undefined reference to
   `irq_actor_none'
   riscv64-linux-gnu-ld: prelink.o:(.rodata+0x18): undefined reference to
   `irq_actor_none'
   riscv64-linux-gnu-ld: prelink.o:(.rodata+0x20): undefined reference to
   `irq_actor_none'
   riscv64-linux-gnu-ld: xen-syms: hidden symbol `irq_actor_none' isn't
   defined

That is why these stubs were introduced in the previous patch (because
common/irq.c isn't built at that moment) and are removed in this patch
(since at the moment of this patch, common/irq.c is now being built).

~ Oleksii

> 
> (This patch has to be the final one touching build related things, so
> I
> can't simply fix it on commit)
> 
> ~Andrew