On Tue, May 18, 2004 at 03:25:39PM -0700, Jun Sun wrote: > > > > IDE PIO fills the D-cache with the read data (write allocate) as it > > copies it to the page cache. > > > > The kernel maps the page cache page into user space ... BANG! possible > > D-cache alias. > > > > The kernel doesn't bother flushing the page cache page from the D-cache > > as it's never accessed at it's page cache address. > > > > The kernel (or driver) should flush the page if it is mapped to user space > and the content is modified. > We just need a hook so that we can flush a page from the D-cache once it's read from a block device into the page cache. > > The current fix in the Cobalt patches (2.4 & 2.6) just flushes the read > > data out of the D-cache after every IDE insw()/insl(). This is the least > > intrusive fix. > > > > It should be fixed at a higher layer before we return back to userland. > > If you can illustrate the call stack, I can probably take a look and > give my opinion. > No call stack, sorry. It was months ago that I debugged this. IIRC I picked up the aliases with memcmp() in do_no_page() in mm/memory.c. P.
