[PATCH v2 0/9] arm64: clean up early boot function calls

On 30 August 2016 at 15:48, Mark Rutland [off-list ref] wrote:

Hi,

On Wed, Aug 24, 2016 at 04:35:57PM +0200, Ard Biesheuvel wrote:

quoted

This v2 series is a followup to the single patch #1, whose v1 I sent out
about a week ago.

In a couple of places, the early boot code uses non-standard argument,
return value or return address registers when calling functions. This makes
the code more complicated than it needs to be, which was not a problem in the
early days, but with all the recent changes for KASLR, hibernate etc, it
makes sense to clean this up once and for all. This code removes all uses of
callee saved registers on the secondary boot and resume paths, and on th
primary boot path, it only leaves the necessary ones, and documents them
explicitly in patch #9.

I will leave it to the honourable arm64 maintainers to decide if any of
these improvements weigh up against the churn, given that this code has
already been updated numerous times over the past couple of kernel versions.

Which ones are honourable? ;)

FWIW, I think that overall this is a nice improvement in legibility for
the boot code.

quoted

Adding James to cc since patch #6 may conflict with this hibernate/
debug-pagealloc series [0], to which I replied that merging .idmap.text
with .mmuoff.text would be a worthwhile simplification.

I'll leave it to you, James, and the honourable maintainers to figure
out the details on that front.

Thanks. James's patches have been queued already, so I can simply
rebase onto for-next/core, with the caveat that it does not have your
KASLR TLB fix yet.

I've given this a spin on Juno (R1) with KASAN and CONFIG_RANDOMIZE_BASE
selected (though I have no entropy source, so I'm bailing out early).
That all works, so for the series:

Tested-by: Mark Rutland <mark.rutland@arm.com>

For patch 1, feel free to upgrade the Acked-by to a Reviewed-by to match
the rest of the series.

Thanks a lot!

-- 
Ard.