Re: [RFC PATCH 1/3] pstore-ram: use write-combine mappings

[Wei Ni]

> Atomic operations are undefined behavior on ARM for device or strongly
> ordered memory types. So use write-combine variants for mappings. This
> corresponds to normal, non-cacheable memory on ARM. For many other
> architectures, this change should not change the mapping type.

Hi, all
I have met this problems on tegra soc.
I tried to use pstore-ram, but the system will hang up when run the
atomic_cmpxchg() in the buffer_start_add() or buffer_size_add(),
whatever I use iomapped or vmapped regions.

I tried to apply this patch set, it was failed with vmap, but if use
iomapped rgiions, the ldrex/strex can work on this memory, and the
ramoops driver can work.

Does there have any updates for this issue?
Or how can I debug it?

Thanks.
Wei.
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