Hi Ash, Le 11/02/2022 à 12:29, Michael Ellerman a écrit : > Ash Logan <ash@xxxxxxxxxxxx> writes: >> - Like the Wii before it, the Wii U has a small amount of RAM at address >> zero, a gap, then a large amount of RAM at a higher address. Instead of >> the "map everything and reserve the gap" approach of the Wii, we loop >> over each memblock and map only true RAM[9]. This seems to work, but as >> far as I can tell is unique amongst powerpc32 platforms, so it's worth >> pointing out. (Note: I've been told this doesn't work anymore after some >> KUAP changes[10], so this point might be moot; haven't investigated) > > We'd need more detail on that I guess. Currently all the 32-bit > platforms use the flat memory model, which assumes RAM is a single > contiguous block. Though that doesn't mean it all has to be used or > mapped, like the Wii does. To properly support your layout you should be > using sparsemem, but it's possible that's more trouble than it's worth, > I'm not sure. How far apart are the low and high blocks of RAM, and what > are their sizes? Can you provide details on what's happening with KUAP changes ? You are pointing to series https://lkml.org/lkml/2021/6/3/204 Does it work when CONFIG_PPC_KUAP is not selected or doesn't it work either ? Are you able to bisect which commit of that series is the culprit ? Thanks Christophe
