arm64: mm: make vmemmap region a projection of the linear region

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Now that we have reverted the introduction of the vmemmap struct page
pointer and the separate physvirt_offset, we can simplify things further,
and place the vmemmap region in the VA space in such a way that virtual
to page translations and vice versa can be implemented using a single
arithmetic shift.

One happy coincidence resulting from this is that the 48-bit/4k and
52-bit/64k configurations (which are assumed to be the two most
prevalent) end up with the same placement of the vmemmap region. In
a subsequent patch, we will take advantage of this, and unify the
memory maps even more.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Steve Capper <steve.capper@arm.com>
Link: https://lore.kernel.org/r/20201008153602.9467-4-ardb@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

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Ard Biesheuvel 2020-10-08 17:36:01 +02:00 • committed by Catalin Marinas

parent f4693c2716

commit 8c96400d6a

3 changed files with 23 additions and 23 deletions

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30

Documentation/arm64/memory.rst

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14

arch/arm64/include/asm/memory.h

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2

arch/arm64/mm/init.c

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