Re: [PATCH v2 05/20] x86, ACPI: Split acpi_initrd_override to find/copy two functions

[Tejun Heo <tj@kernel.org>]

On Sat, Mar 09, 2013 at 10:44:32PM -0800, Yinghai Lu wrote:
> To parse srat early, we need to move acpi table probing early.
> acpi_initrd_table_override is before acpi table probing. So we need to
> move it early too.
> 
> Current code acpi_initrd_table_override is after init_mem_mapping and
> relocate_initrd(), so it can scan initrd and copy acpi tables with kernel
> virtual address of initrd.
> Copying need to be after memblock is ready, because it need to allocate
> buffer for new acpi tables.
> 
> So we have to split that function to find and copy two functions.
> Find should be as early as possible. Copy should be after memblock is ready.
> 
> Finding could be done in head_32.S and head64.c, just like microcode
> early scanning. In head_32.S, it is 32bit flat mode, we don't
> need to set page table to access it. In head64.c, #PF set page table
> could help us access initrd with kernel low mapping address.
> 
> Copying could be done just after memblock is ready and before probing
> acpi tables, and we need to early_ioremap to access source and target
> range, as init_mem_mapping is not called yet.
> 
> Also move down two functions declaration to avoid #ifdef in setup.c
> 
> ACPI_INITRD_TABLE_OVERRIDE depends one ACPI and BLK_DEV_INITRD.
> So could move declaration out from #ifdef CONFIG_ACPI protection.

Heh, I couldn't really follow the above.  How about something like the
following.

 While a dummy version of acpi_initrd_override() was defined when
 !CONFIG_ACPI_INITRD_TABLE_OVERRIDE, the prototype and dummy version
 were conditionalized inside CONFIG_ACPI.  This forced setup_arch() to
 have its own #ifdefs around acpi_initrd_override() as otherwise build
 would fail when !CONFIG_ACPI.  Move the prototypes and dummy
 implementations of the newly split functions below CONFIG_ACPI block
 in acpi.h so that we can do away with #ifdefs in its user.

Acked-by: Tejun Heo <tj@kernel.org>

Thanks.

-- 
tejun