The CFE bootloader places a stub program at 0x0000-0xFFFF to hold the
secondary CPUs until the boot CPU writes the release address. If Linux
overwrites this program before execution reaches smp_prepare_cpus(), the
secondary CPUs may become inaccessible.
This is only a problem with CFE, and then only until the secondary CPUs
are brought online. However, since it is such a small amount of memory,
it is easiest to reserve it unconditionally.
Therefore, add a /reserved-memory node to bcm4908.dtsi to protect this
critical memory region.
Signed-off-by: Sam Edwards <CFSworks@xxxxxxxxx>
---
arch/arm64/boot/dts/broadcom/bcmbca/bcm4908.dtsi | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/arch/arm64/boot/dts/broadcom/bcmbca/bcm4908.dtsi b/arch/arm64/boot/dts/broadcom/bcmbca/bcm4908.dtsi
index 8b924812322c..326f84f746cb 100644
--- a/arch/arm64/boot/dts/broadcom/bcmbca/bcm4908.dtsi
+++ b/arch/arm64/boot/dts/broadcom/bcmbca/bcm4908.dtsi
@@ -68,6 +68,16 @@ l2: l2-cache0 {
};
};
+ reserved-memory {
+ #address-cells = <2>;
+ #size-cells = <2>;
+ ranges;
+
+ cfe-stub@0 {
+ reg = <0 0 0 0x10000>;
+ };
+ };
+
axi@81000000 {
compatible = "simple-bus";
#address-cells = <1>;
--
2.44.2
