Re: [PATCH 04/10] module: make MODULE_SYMBOL_PREFIX into a CONFIG option

[Mike Frysinger <vapier.adi@gmail.com>]

On Tue, Nov 3, 2009 at 07:16, Alan Jenkins wrote:
> Mike Frysinger wrote:
>> On Tue, Nov 3, 2009 at 05:06, Alan Jenkins wrote:
>>> The next commit will require the use of MODULE_SYMBOL_PREFIX in
>>> .tmp_exports-asm.S.  Currently it is mixed in with C structure
>>> definitions in "asm/module.h".  Move the definition of this arch option
>>> into Kconfig, so it can be easily accessed by any code.
>>>
>>> This also lets modpost.c use the same definition.  Previously modpost
>>> relied on a hardcoded list of architectures in mk_elfconfig.c.
>>
>> this should also let us push VMLINUX_SYMBOL() out of
>> arch/*/kernel/vmlinux.lds.S and into asm-generic/vmlinux.lds.h ...
>
> I don't think that's possible.
>
>   #define VMLINUX_SYMBOL(_sym_) _##_sym_
>
> I don't know any "unstringify" operation.  So I can't convert a string value
> of CONFIG_SYMBOL_PREFIX to the unquoted underscore we neeed for this macro.
>  The same applies for the SYM() macro I use.

let the build system do the unstringify operation.
qstrip = $(strip $(subst ",,$(1)))
CPPFLAGS_vmlinux.lds += -DVMLINUX_SYMBOL_PREFIX=$(call
qstrip,CONFIG_SYMBOL_PREFIX)

> If we positively want to keep the generality, I guess I should put
> MODULE_SYMBOL_PREFIX in a header file of it's own.  The disadvantage is that
> it makes it inaccessible to host programs again, like modpost (which
> currently hardcodes the list of affected architectures in mk_elfconfig.c).

having it in the arch Kconfig removes any and all possible
limitations, and it keeps the cruft out of the common init/Kconfig and
in the arch-specific Kconfig, and avoids a dead symbol
(HAVE_SYMBOL_PREFIX)
-mike