arm64: mmu: Make page table manipulation work across stages

In order to have a proper runtime-modifyable page table API (e.g. to
remap DRAM after it was intialized), we need to remove any external
bookkeeping kept in global variables (which do not persist across
stages) from the MMU code. This patch implements this in a similar way
as it has recently been done for ARM32 (marking free table slots with a
special sentinel value in the first PTE that cannot occur as part of a
normal page table).

Since this requires the page table buffer to be known at compile-time,
we have to remove the option of passing it to mmu_init() at runtime
(which I already kinda deprecated before). The existing Tegra chipsets
that still used it are switched to instead define it in memlayout in a
minimally invasive change. This might not be the best way to design this
overall (I think we should probably just throw the tables into SRAM like
on all other platforms), but I don't have a Tegra system to test so I'd
rather keep this change low impact and leave the major redesign for
later.

Also inlined some single-use one-liner functions in mmu.c that I felt
confused things more than they cleared up, and fixed an (apparently
harmless?) issue with forgetting to mask out the XN page attribute bit
when casting a table descriptor to a pointer.

BRANCH=None
BUG=None
TEST=Compiled Ryu and Smaug. Booted Oak.

Change-Id: Iad71f97f5ec4b1fc981dbc8ff1dc88d96c8ee55a
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: http://review.coreboot.org/12075
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/soc/nvidia/tegra210/include/soc/memlayout.ld b/src/soc/nvidia/tegra210/include/soc/memlayout.ld
index d24f980207ac..0338cd9604db 100644
--- a/src/soc/nvidia/tegra210/include/soc/memlayout.ld
+++ b/src/soc/nvidia/tegra210/include/soc/memlayout.ld
@@ -38,4 +38,5 @@ SECTIONS
 	DRAM_START(0x80000000)
 	POSTRAM_CBFS_CACHE(0x80100000, 1M)
 	RAMSTAGE(0x80200000, 256K)
+	TTB(0x100000000 - CONFIG_TTB_SIZE_MB * 1M, CONFIG_TTB_SIZE_MB * 1M)
 }