This patch adds an mmu_config_range_kb() function, which can set memory
types at the 4KB level by chaining a fine-grained page table to an
existing superpage entry. It is only intended for special cases where
this level of precision is really necessary and therefore comes with a
few practical limitations (the area for each invocation must be confined
within a single superpage, and you are not allowed to remap the same
region with mmu_config_range() again later). Since the fine-grained page
tables need some space, boards intending to use this feature must define
a TTB_SUBTABLES() region in their memlayout.ld.
BUG=chrome-os-partner:32848
TEST=Booted both Veyron_Pinky (normal) and Nyan_Blaze (LPAE), ensured
that they still work. Checksummed the page tables with and without this
patch, confirmed that they end up equal. Hacked in some subtable test
entries, hexdumped all tables and manually confirmed that they look as
expected.
Change-Id: Iedf7ca435ae337ead85115200d6987fb0d4828d7
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/223781
2f13e60cf5