Re: [Xen-devel] [PATCH v6 1/9] efi: Use early_mem*() instead of early_io*()

[Daniel Kiper <daniel.kiper@xxxxxxxxxx>]

I am CC'ing IA-64 guys.

On Mon, Jun 23, 2014 at 08:19:00AM +0100, Jan Beulich wrote:
> >>> On 20.06.14 at 23:29, <daniel.kiper@xxxxxxxxxx> wrote:
> > --- a/drivers/firmware/efi/efi.c
> > +++ b/drivers/firmware/efi/efi.c
> > @@ -298,7 +298,7 @@ int __init efi_config_init(efi_config_table_type_t 
> > *arch_tables)
> >                     if (table64 >> 32) {
> >                             pr_cont("\n");
> >                             pr_err("Table located above 4GB, disabling 
> > EFI.\n");
> > -                           early_iounmap(config_tables,
> > +                           early_memunmap(config_tables,
> >                                            efi.systab->nr_tables * sz);
> >                             return -EINVAL;
> >                     }
> > @@ -314,7 +314,7 @@ int __init efi_config_init(efi_config_table_type_t 
> > *arch_tables)
> >             tablep += sz;
> >     }
> >     pr_cont("\n");
> > -   early_iounmap(config_tables, efi.systab->nr_tables * sz);
> > +   early_memunmap(config_tables, efi.systab->nr_tables * sz);
> >
> >     set_bit(EFI_CONFIG_TABLES, &efi.flags);
> >
>
> If these two changes are really deemed necessary (there's the
> implied assumption currently in place that early_iounmap() can
> undo early_memremap() mappings), then ia64 will need a
> definition added for early_memunmap() or its build will break.

I know that early_memunmap() == early_iounmap() in general. However,
I think that it is less confusing if use relevant functions in pairs
(i.e. early_memremap() with early_memunmap(), ...) than mix them up.

We have following choices here:
  - leave early_iounmap() as is in drivers/firmware/efi/efi.c
    (arch/x86/platform/efi/efi.c:early_iounmap() -> early_memunmap()
    changes should be left as is),
  - include asm/early_ioremap.h in arch/ia64/include/asm/io.h
    (as I can see the same think is done for x86 and arm64).

I prefer second solution but I do not insist.

Daniel

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