Re: [PATCH 2/2] platform/x86: Add Intel Galileo platform specific setup

From: Bryan O'Donoghue
Date: Sat Jan 10 2015 - 20:54:26 EST



I'm wondering if there is a need for this to be a platform driver at
all. Could we, instead, tear down any unlocked IMRs at boot as part of the IMR
driver itself, as well as lock the kernel .text. Firmware has the option of
making an IMR mandatory by locking it. If it isn't locked, what use is it to the
OS without a lot more context? Any sort of policy enforced with IMRs is a
user-space decision, so clearing out the unlocked ones and then handing off to
user-space seems like a sane default mode to me.

I discussed this with Boon Leong this afternoon and we couldn't come up with a
justification for a platform-specific driver to do what this does.

I think there's no technical reason impeding what you've just suggested in the IMR init and I'm happy to move the code in there since basically any platform with IMR registers could justifiably

a) Tear down everything that's unlocked
b) Place a default IMR around the .text section

No reason it the world that that policy needs to be Galileo specific - and it's a valid argument to say - this behaviour can simply be an IMR policy in the kernel and less code for the same functionality, that adds consistency across x86 is a good thing.

I'll zap the Galileo platform code entirely for V2 unless there's a counter-argument from someone.

--
BOD

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