linux-kernel - Re: [RFC PATCH v3 3/4] arm64: Handle miscellaneous functions in .text and .init.text

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Message-ID: <cb2c47ee-97d7-15d8-05db-b8e3e260b782@linux.microsoft.com>
Date:   Thu, 6 May 2021 10:32:30 -0500
From:   "Madhavan T. Venkataraman" <madvenka@...ux.microsoft.com>
To:     Mark Brown <broonie@...nel.org>
Cc:     jpoimboe@...hat.com, mark.rutland@....com, jthierry@...hat.com,
        catalin.marinas@....com, will@...nel.org, jmorris@...ei.org,
        pasha.tatashin@...een.com, linux-arm-kernel@...ts.infradead.org,
        live-patching@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH v3 3/4] arm64: Handle miscellaneous functions in .text
 and .init.text



On 5/6/21 10:30 AM, Madhavan T. Venkataraman wrote:
>> I was thinking it'd be good to do this by modifying SYM_CODE_START() to
>> emit the section, that way nobody can forget to put any SYM_CODE into a
>> special section.  That does mean we'd have to first introduce a new
>> variant for specifying a section that lets us override things that need
>> to be in some specific section and convert everything that's in a
>> special section over to that first which is a bit annoying but feels
>> like it's worth it for the robustness.  It'd also put some of the don't
>> cares into .code.text but so long as they are actually don't cares that
>> should be fine!
>>
> OK. I could make the section an argument to SYM_CODE*() so that a developer
> will never miss that. Some documentation may be in order so the guidelines
> are clear. I will do the doc patch separately, if that is alright with
> you all.

There is just one problem with this. Sometimes, there is some data in the
same text section. That data will not get included when we do the SYM_CODE(section)
change.

Madhavan