On Tue, Aug 28, 2001 at 07:17:25PM +0200, Tom Appermont wrote:
> While this works as expected on PC, it does not at all work as
> expected on my mips platform (R5231): What is written in user
> space is not immediately visible in kernel space. This is with
> very recent kernel sources (2.4.8) but the same problem exists
> with an older (2.4.5) kernel.
> There have been a few mails about mmap() problems in the last
> couple of months, but with very little interesting response. Is
> this a known problem or am I stupidly overlooking something?
This is a different problem - and it's one caused by your code. You're
missing the necessary cache flushes in the kernel code. Using
_CACHE_UNCACHED is slow and breaks SMP.