tree abb02b93d0b8bf50b8b3df66f0493a7a4723fd2b
parent ea96f947b5304fdde2e0991d23febaeba209dde1
author Julius Werner <jwerner@chromium.org> 1443572895 -0700
committer ChromeOS bot <3su6n15k.default@developer.gserviceaccount.com> 1443725488 +0000

armv7: mmu: Make fine grained page tables work across stages

Among its other restrictions (which are noted in a comment above the
function prototype and stay in place), our makeshift fine-grained page
table support for ARM32 has the undocumented feature that it relies on
a global bookkeeping variable, causing all sorts of fun surprises when
you try to use it from multiple stages during the same boot. This patch
redesigns the bookkeeping to stay completely inline in the (persistent)
TTB which should resolve the issue. (This had not been a problem on any
of our platforms for now... I just noticed this because I was trying to
solve the same issue on ARM64.)

BRANCH=None
BUG=None
TEST=Booted veyron_jerry. Mapped a second fine-grained memory range
from romstage, confirmed that it finds the next free spot and leaves the
bootblock table in place.

Change-Id: I325866828b4ff251142e1131ce78b571edcc9cf9
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/302955
Reviewed-by: Aaron Durbin <adurbin@chromium.org>