Re: [PATCH 2/2] ARM: mm: hide __start_rodata_section_aligned for non-debug builds

From	Ard Biesheuvel <ard.biesheuvel@linaro.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH 2/2] ARM: mm: hide __start_rodata_section_aligned for non-debug builds
Date	2016-02-16 17:40 +0100
Message-ID	<r2QPo-1Uv-23@gated-at.bofh.it> (permalink)
References	<r2Qmm-1Is-13@gated-at.bofh.it> <r2Qmm-1Is-11@gated-at.bofh.it> <r2Qw2-1LV-11@gated-at.bofh.it> <r2QPo-1Uv-15@gated-at.bofh.it>
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On 16 February 2016 at 17:34, Arnd Bergmann <arnd@arndb.de> wrote:
> On Tuesday 16 February 2016 17:12:52 Ard Biesheuvel wrote:
>> > +#ifdef CONFIG_DEBUG_RODATA
>> >  /*
>> >   * Without CONFIG_DEBUG_ALIGN_RODATA, __start_rodata_section_aligned will
>> >   * be the first section-aligned location after __start_rodata. Otherwise,
>> >   * it will be equal to __start_rodata.
>> >   */
>> >  __start_rodata_section_aligned = ALIGN(__start_rodata, 1 << SECTION_SHIFT);
>> > +#endif
>> >
>>
>> Does
>>
>> PROVIDE(__start_rodata_section_aligned = xxx);
>>
>> do the trick as well? If it does, it's a bit cleaner.
>>
>
> I would assume not, as the problem is that SECTION_SHIFT is a macro that
> is not defined when the MMU is disabled.
>

I just tested it myself, and it in fact does work.

PROVIDE() means the expression is evaluated lazily, and SECTION_SHIFT
is just an undefined identifier in the linker script scope if the
preprocessor does not define it.

Anyway, I don't have a strong preference, so ack either way.

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[PATCH 2/2] ARM: mm: hide __start_rodata_section_aligned for non-debug builds Arnd Bergmann <arnd@arndb.de> - 2016-02-16 17:10 +0100
  Re: [PATCH 2/2] ARM: mm: hide __start_rodata_section_aligned for  non-debug builds Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2016-02-16 17:20 +0100
    Re: [PATCH 2/2] ARM: mm: hide __start_rodata_section_aligned for non-debug builds Arnd Bergmann <arnd@arndb.de> - 2016-02-16 17:40 +0100
      Re: [PATCH 2/2] ARM: mm: hide __start_rodata_section_aligned for  non-debug builds Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2016-02-16 17:40 +0100

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