[XS] Change in coreboot[main]: mainboard/qemu-aarch64: Get top of memory from device-tree blob

[Alper Nebi Yasak (Code Review)]

Attention is currently required from: Alper Nebi Yasak, Nico Huber.

Hello Nico Huber, build bot (Jenkins),

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/80364?usp=email

to look at the new patch set (#5).

The following approvals got outdated and were removed:
Verified+1 by build bot (Jenkins)

Change subject: mainboard/qemu-aarch64: Get top of memory from device-tree blob
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mainboard/qemu-aarch64: Get top of memory from device-tree blob

Trying to probe RAM space to figure out top of memory causes an
exception on AArch64 virtual machines with recent versions of QEMU, but
we temporarily enable exception handlers for that and use it to help
detect if a RAM address is usable or not. However, QEMU docs recommend
reading device information from the device-tree blob it provides us at
the start of RAM.

A previous commit adds a library function to parse device-tree blob that
QEMU provides us. Use it to determine top of memory in AArch64 QEMU
virtual machines, but still fall back to the RAM probing approach as a
last-ditch effort.

Change-Id: I4cc888b57cf98e0797ce7f9ddfa2eb34d14cd9c1
Signed-off-by: Alper Nebi Yasak 
---
M src/mainboard/emulation/qemu-aarch64/Kconfig
M src/mainboard/emulation/qemu-aarch64/cbmem.c
2 files changed, 8 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/64/80364/5