Re: [v5.4 stable] arm: stm32: Regression observed on "no-map" reserved memory region

Hi Alexandre,

On Friday 07 May 2021 at 17:15:20 (+0200), Alexandre TORGUE wrote:

Did you get time to continue some tests on this issue ?

I did try a few things, but still fail to reproduced :/

On my side this DT is not working:

memory@c0000000 {
        reg = <0xc0000000 0x20000000>;
};

reserved-memory {
        #address-cells = <1>;
        #size-cells = <1>;
        ranges;

        gpu_reserved: gpu@d4000000 {
                reg = <0xd4000000 0x4000000>;
                no-map;
        };
};

So this does change how memory appears in /proc/iomem for me switching
from 5.4.101 to v5.4.102 -- for the former d4000000-d7ffffff doesn't
appear at all, and for the latter it appears as 'reserved'.

But still, it never gets accounted as System RAM for me ...

Let me know if I can help.

Could you please confirm you get a correct behaviour with 5.10.31 like
Florian? If so, then bisecting to figure out what we're missing in older
LTSes would help, but again it feels like we should just revert -- this
wasn't really a fix in the first place.

Thanks,
Quentin