Re: [PATCH] arm64/crypto: fix makefile rule for aes-glue-%.o

From: Ard Biesheuvel
Date: Fri Jul 25 2014 - 02:28:19 EST


On 24 July 2014 22:45, Sam Ravnborg <sam@xxxxxxxxxxxx> wrote:
> On Thu, Jul 24, 2014 at 09:25:13PM +0200, Ard Biesheuvel wrote:
>> On 24 July 2014 18:12, Sam Ravnborg <sam@xxxxxxxxxxxx> wrote:
>> > On Thu, Jul 24, 2014 at 04:24:48PM +0200, Ard Biesheuvel wrote:
>> >> On 24 July 2014 16:18, Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> wrote:
>> >> > On 24 July 2014 15:40, Andreas Schwab <schwab@xxxxxxx> wrote:
>> >> >> Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> writes:
>> >> >>
>> >> >>> On 24 July 2014 15:26, Andreas Schwab <schwab@xxxxxxx> wrote:
>> >> >>>> You are not using CONFIG_MODVERSIONS.
>> >> >>>>
>> >> >>>
>> >> >>> I am
>> >> >>
>> >> >> No, you aren't, since you say that your .cmd contains a command to
>> >> >> create aes-glue-ce.o, which with CONFIG_MODVERSIONS it doesn't.
>> >> >>
>> >> >
>> >> > OK, you're right, it contains a command to create .tmp_aes-glue-ce.o.
>> >> > But I am still not seeing the error you are seeing, strangely enough.
>> >>
>> >> OK, now I am seeing it.
>> >>
>> >> Acked-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
>> >
>> > Jumping in the end of the thread here - sorry for that.
>> >
>>
>> No worries
>>
>> > Another way to solve this would be to create two
>> > small wrapper files:
>> > aes-glue-neon.c - which include aes-glue.c
>> > aes-glue-ce.c that include aes-glue.c
>> >
>> > Then you could use standard kbuild support for building your module.
>> > And we will not potentially break it when we change cc_o_c in the near future.
>> >
>>
>> I see how that would fix this issue, but frankly, if we need to add .c
>> files that only #include other .c files to support building multiple
>> objects from a single .c file, I think the flaw is in the build
>> system, and I would rather fix the build system instead.
> The kbuild syntax could be extended to allow building multiple .o files from
> a single .c file. But the need for this feature is so seldom that
> people would not recognize the syntax most likely.
>

True

> Btw. the current solution is already faulty - even with the fix.
> There are no support for make C=2 arch/.../crypto/
>

So can you elaborate on how it is faulty?

> Therefore - for now the correct fix is to use two wrapper .c files,
> and accept this. It will not have the C=2 problem above.
>
> Sam
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