Tegra186 currently restricts its DRAM usage to entries in the /memory node
in the DTB passed to it. However, the MMU configuration always maps the
entire first 2GB of RAM. This could allow the CPU to speculatively access
RAM that isn't part of the in-use banks. This patch switches to runtime
construction of the table that's used to construct the MMU translation
tables, and thus prevents access to RAM that's not part of a valid bank.
Note: This patch is intended to prevent access to RAM regions which U-Boot
does not need to access, with the primary purpose of avoiding theoretical
speculative access to physical regions for which the HW will throw errors
(e.g. carve-outs that the CPU has no permission to access at a bus level,
bad ECC pages, etc.). In particular, this patch is not deliberately
related to the speculation-related security issues that were recently
announced. The apparent similarity is a coincidence.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>
In the future, the list of DRAM regions passed to U-Boot in the DTB may
be quite long and fragmented. Due to this, U-Boot must search through the
regions to find the best region to relocate into, rather than relying on
the current assumption that the top of bank 0 is a reasonable relocation
target. This change implements such searching.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
Apply a few small fixes for the DTB /memory node parsing from NVIDIA's
downstream U-Boot:
- Allow arbitrary number of DRAM banks.
- Correctly calculate the number of DRAM banks.
- Clip PCIe memory in the same way as U-Boot CPU memory use.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
U-Boot widely uses error() as a bit noisier variant of printf().
This macro causes name conflict with the following line in
include/linux/compiler-gcc.h:
# define __compiletime_error(message) __attribute__((error(message)))
This prevents us from using __compiletime_error(), and makes it
difficult to fully sync BUILD_BUG macros with Linux. (Notice
Linux's BUILD_BUG_ON_MSG is implemented by using compiletime_assert().)
Let's convert error() into now treewide-available pr_err().
Done with the help of Coccinelle, excluing tools/ directory.
The semantic patch I used is as follows:
// <smpl>
@@@@
-error
+pr_err
(...)
// </smpl>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
[trini: Re-run Coccinelle]
Signed-off-by: Tom Rini <trini@konsulko.com>
These two functions have an of_ prefix which conflicts with naming used
in of_addr. Rename them:
fdt_read_number
fdt_support_bus_default_count_cells
Signed-off-by: Simon Glass <sjg@chromium.org>
By making dram_init_banksize() return an error code we can drop the
wrapper. Adjust this and clean up all implementations.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Stefan Roese <sr@denx.de>
On Tegra186, U-Boot is booted by the binary firmware as if it were a
Linux kernel. Consequently, a DTB is passed to U-Boot. Cache the address
of that DTB, and parse the /memory/reg property to determine the actual
RAM regions that U-Boot and subsequent EL2/EL1 SW may actually use.
Given the binary FW passes a DTB to U-Boot, I anticipate the suggestion
that U-Boot use that DTB as its control DTB. I don't believe that would
work well, so I do not plan to put any effort into this. By default the
FW-supplied DTB is the L4T kernel's DTB, which uses non-upstreamed DT
bindings. U-Boot aims to use only upstreamed DT bindings, or as close as
it can get. Replacing this DTB with a DTB using upstream bindings is
physically quite easy; simply replace the content of one of the GPT
partitions on the eMMC. However, the binary FW at least partially relies
on the existence/content of some nodes in the DTB, and that requires the
DTB to be written according to downstream bindings. Equally, if U-Boot
continues to use appended DTBs built from its own source tree, as it does
for all other Tegra platforms, development and deployment is much easier.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>
