[PATCH v4 03/19] arm64: asm-offsets: Remove potential circular dependency

[Christoffer Dall]

On Mon, Jan 15, 2018 at 9:42 AM, Marc Zyngier <marc.zyngier at arm.com> wrote:
> On 15/01/18 08:34, Christoffer Dall wrote:
>> On Thu, Jan 04, 2018 at 06:43:18PM +0000, Marc Zyngier wrote:
>>> So far, we've been lucky enough that none of the include files
>>> that asm-offsets.c requires include asm-offsets.h. This is
>>> about to change, and would introduce a nasty circular dependency...
>>>
>>> Let's now guard the inclusion of asm-offsets.h so that it never
>>> gets pulled from asm-offsets.c. The same issue exists between
>>> bounce.c and include/generated/bounds.h, and is worked around
>>> by using the existing guard symbol.
>>>
>>> Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
>>> ---
>>>  arch/arm64/include/asm/asm-offsets.h | 2 ++
>>>  arch/arm64/kernel/asm-offsets.c      | 2 ++
>>>  2 files changed, 4 insertions(+)
>>>
>>> diff --git a/arch/arm64/include/asm/asm-offsets.h b/arch/arm64/include/asm/asm-offsets.h
>>> index d370ee36a182..7d6531a81eb3 100644
>>> --- a/arch/arm64/include/asm/asm-offsets.h
>>> +++ b/arch/arm64/include/asm/asm-offsets.h
>>> @@ -1 +1,3 @@
>>> +#if !defined(__GENERATING_ASM_OFFSETS_H) && !defined(__GENERATING_BOUNDS_H)
>>
>> I don't understand why we need to check __GENERATING_BOUNDS_H here?
>> What is the interaction between asm-offsets and bounds?
>
> bound.c ends up including asm-offsets.h as well once you start adding
> the dependency between it and alternatives.h. See the report there:
>
> https://www.spinics.net/lists/arm-kernel/msg623723.html
>
> which this check addresses.
>
Ah, I see.

Thanks,
-Christoffer