Re: [PATCH v5 4/5] xen/riscv: introduce early_printk basic stuff

[Julien Grall <julien@xxxxxxx>]

Hi,

On 20/01/2023 00:48, Andrew Cooper wrote:
> On 19/01/2023 2:07 pm, Oleksii Kurochko wrote:
> > diff --git a/xen/arch/riscv/early_printk.c b/xen/arch/riscv/early_printk.c
> > new file mode 100644
> > index 0000000000..6f590e712b
> > --- /dev/null
> > +++ b/xen/arch/riscv/early_printk.c
> > @@ -0,0 +1,45 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * RISC-V early printk using SBI
> > + *
> > + * Copyright (C) 2021 Bobby Eshleman <bobbyeshleman@xxxxxxxxx>
> > + */
> > +#include <asm/early_printk.h>
> > +#include <asm/sbi.h>
> > +
> > +/*
> > + * early_*() can be called from head.S with MMU-off.
> > + *
> > + * The following requiremets should be honoured for early_*() to
> > + * work correctly:
> > + *    It should use PC-relative addressing for accessing symbols.
> > + *    To achieve that GCC cmodel=medany should be used.
> > + */
> > +#ifndef __riscv_cmodel_medany
> > +#error "early_*() can be called from head.S with MMU-off"
> > +#endif
> This comment is false, and the check is bogus.
You are already said that in the previous version and ... I reply back 
explaining why I think this is correct (see [1]).
>  > It needs deleting.
That might be the second step. The first step is we settle down on the 
approach.
Cheers,

[1] 
https://lore.kernel.org/xen-devel/CAF3u54C2ewEfBN+ZT6VPaVu4vsqS_+12gr3YJ_jsg1sGHDhZ1A@xxxxxxxxxxxxxx/
--
Julien Grall