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Subject: Re: [PATCH v1] microblaze: tag highmem_setup() with __meminit
To:     Oscar Salvador <osalvador@suse.de>
Cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        kernel test robot <lkp@intel.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Michal Simek <monstr@monstr.eu>,
        Mike Rapoport <rppt@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Arvind Sankar <nivedita@alum.mit.edu>,
        Ira Weiny <ira.weiny@intel.com>,
        Randy Dunlap <rdunlap@infradead.org>,
        Anshuman Khandual <anshuman.khandual@arm.com>
References: <20210301114749.47914-1-david@redhat.com>
 <20210301221846.GA4744@localhost.localdomain>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat GmbH
Message-ID: <b38b353b-7138-373b-057a-a4fa4b4ab30e@redhat.com>
Date:   Tue, 2 Mar 2021 10:04:47 +0100
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On 01.03.21 23:18, Oscar Salvador wrote:
> On Mon, Mar 01, 2021 at 12:47:49PM +0100, David Hildenbrand wrote:
>> With commit a0cd7a7c4bc0 ("mm: simplify free_highmem_page() and
>> free_reserved_page()") the kernel test robot complains about a warning:
>>
>> WARNING: modpost: vmlinux.o(.text.unlikely+0x23ac): Section mismatch in
>>    reference from the function highmem_setup() to the function
>>    .meminit.text:memblock_is_reserved()
>>
>> This has been broken ever since microblaze added highmem support,
>> because memblock_is_reserved() was already tagged with "__init" back then -
>> most probably the function always got inlined, so we never stumbled over
>> it.
> 
> It might be good to point out that we need __meminit instead of __init
> because microblaze platform does not define CONFIG_ARCH_KEEP_MEMBLOCK,
> and __init_memblock fallsback to that.
> 
> (I had to go and look as I was puzzled :-) )
> 
> Reviewed-by: Oscar Salvador <osalvador@suse.de>

Thanks!

Whoever feels like picking this up (@Andrew?) can you add

"We need __meminit because __init_memblock defaults to that without 
CONFIG_ARCH_KEEP_MEMBLOCK" and __init_memblock is not used outside 
memblock code.

-- 
Thanks,

David / dhildenb