[PATCH] arm64: dts: broadcom: bcmbca: bcm4908: Reserve CFE stub area

Florian Fainelli florian.fainelli at broadcom.com
Thu Oct 3 15:41:17 PDT 2024


On 10/3/24 14:30, Sam Edwards wrote:
> 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 at gmail.com>

Not objecting to the solution, but should not this be moved to a 
per-board DTS given that there are boards using CFE, and some using 
u-boot + ARM TF that are unlikely to suffer from that problem?

-- 
Florian



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