IRQs disabling in flush_cache_4096 for cache purge. Under certain
workloads we would get an IRQ in the middle of a purge operation,
and the cachelines would remain in an inconsistent state, leading
to occasional stack corruption.
Signed-off-by: NTakeo Takahashi <takahashi.takeo@renesas.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

flush_cache_mm() wraps in to flush_cache_all(), which is rather
excessive given that the number of PTEs within the specified context
are generally quite low.  Optimize for walking the mm's VMA list and
selectively flushing the VMA ranges from the dcache. Invalidate the
icache only if a VMA sets VM_EXEC.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Currently when making changes to control registers, we
typically need some time for changes to take effect (8
nops, generally).  However, for sh4a we simply need to
do an icbi..

This is a simple patch for implementing a general purpose
ctrl_barrier() which functions as a control register write
barrier. There's some additional documentation in the patch
itself, but it's pretty self explanatory.

There were also some places where we were not doing the
barrier, which didn't seem to have any adverse effects on
legacy parts, but certainly did on sh4a. It's safer to have
the barrier in place for legacy parts as well in these cases,
though this does make flush_tlb_all() more expensive (by an
order of 8 nops).  We can ifdef around the flush_tlb_all()
case for now if it's clear that all legacy parts won't have
a problem with this.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This reworks some of the SH-4 cache handling code to more easily
accomodate newer-style caches (particularly for the > direct-mapped
case), as well as optimizing some of the old code.
Signed-off-by: NRichard Curnow <richard.curnow@st.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

SH-4A supports 'synco' as a barrier, sprinkle it around
the cache ops as necessary..
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

flush_cache_range() wasn't page aligning the end of the range,
we can't assume that it will always be page aligned, and we
ended up getting unaligned faults in some rare call paths.

Additionally, we add a small optimization to just purge the
dcache entirely if the range is large enough that the page
table walking will take longer. We use an arbitrary value of
64 pages for the large range size, as per sh64.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Signed-off-by: NJörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!