rpi4: Reserve resident BL31 region from non-secure world
The GPU firmware loads the armstub8.bin (BL31) image at address 0, the
beginning of DRAM. As this holds the resident PSCI code and the SMP
pens, the non-secure world should better know about this, to avoid
accessing memory owned by TF-A. This is particularly criticial as the
Raspberry Pi 4 does not feature a secure memory controller, so
overwriting code is a very real danger.
Use the newly introduced function to add a node into reserved-memory
node, where non-secure world can check for regions to be excluded from
its mappings.
Reserve the first 512KB of memory for now. We can refine this later if
need be.
Change-Id: I00e55e70c5c02615320d79ff35bc32b805d30770
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
diff --git a/plat/rpi/rpi4/rpi4_bl31_setup.c b/plat/rpi/rpi4/rpi4_bl31_setup.c
index e1b6c89..8dfadf7 100644
--- a/plat/rpi/rpi4/rpi4_bl31_setup.c
+++ b/plat/rpi/rpi4/rpi4_bl31_setup.c
@@ -245,6 +245,10 @@
return;
}
+ /* Reserve memory used by Trusted Firmware. */
+ if (fdt_add_reserved_memory(dtb, "atf@0", 0, 0x80000))
+ WARN("Failed to add reserved memory nodes to DT.\n");
+
ret = fdt_pack(dtb);
if (ret < 0)
ERROR("Failed to pack Device Tree at %p: error %d\n", dtb, ret);
