Re: [PATCH] x86/intel/quark: Remove lock bit around kernel IMR

From	Andy Shevchenko <andy.shevchenko@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] x86/intel/quark: Remove lock bit around kernel IMR
Date	2016-01-22 13:20 +0100
Message-ID	<qTIR4-3TR-29@gated-at.bofh.it> (permalink)
References	<qTofE-6n5-7@gated-at.bofh.it> <qTssX-M0-19@gated-at.bofh.it> <qTHLk-3dT-33@gated-at.bofh.it>
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On Fri, Jan 22, 2016 at 1:08 PM, Bryan O'Donoghue
<pure.logic@nexus-software.ie> wrote:
> On Thu, 2016-01-21 at 20:44 +0200, Andy Shevchenko wrote:
>> On Thu, Jan 21, 2016 at 4:05 PM, Bryan O'Donoghue
>> <pure.logic@nexus-software.ie> wrote:

[]

>> > The solution to this situation is to keep the kernel .text section
>> > IMR lock
>> > bit false. This means that a subsequent kernel will boot and can
>> > tear-down
>> > an existing IMR, while still setting up an IMR around its own .text
>> > section.
>> >
>>
>> Like I said you privately it would be nice to have a knob how to
>> behave.
>
> Ok - that can work. The default ought to be !locked and we can
> parametrize a different behaviour.
>
>
>> My idea is to provide kernel command line imr= and supply imr=lock
>> when user wants to boot kernel locked.
>
> Agreed.
>
>>
>> Optionally: add a warning if imr=lock and kernel build with kexec
>> that
>> might bring issues
>
> This makes sense.
>
>> Optionally: add a kernel config option to boot always in locked mode
>> (should depend on !KEXEC)
>
> Meh. You can still force the state you want with the parameter though.
> I reckon we should skip this change for now.

OK!

P.S. Please, use my @linux.intel.com address in the tags.

-- 
With Best Regards,
Andy Shevchenko

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[PATCH] x86/intel/quark: Remove lock bit around kernel IMR Bryan O'Donoghue <pure.logic@nexus-software.ie> - 2016-01-21 15:20 +0100
  Re: [PATCH] x86/intel/quark: Remove lock bit around kernel IMR Andy Shevchenko <andy.shevchenko@gmail.com> - 2016-01-21 19:50 +0100
    Re: [PATCH] x86/intel/quark: Remove lock bit around kernel IMR Bryan O'Donoghue <pure.logic@nexus-software.ie> - 2016-01-22 12:10 +0100
      Re: [PATCH] x86/intel/quark: Remove lock bit around kernel IMR Andy Shevchenko <andy.shevchenko@gmail.com> - 2016-01-22 13:20 +0100

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