Mtdblock driver doesn't call flush_dcache_page for pages in request.  So,
this causes problems on architectures where the icache doesn't fill from
the dcache or with dcache aliases.  The patch fixes this.

The ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE symbol was introduced to avoid
pointless empty cache-thrashing loops on architectures for which
flush_dcache_page() is a no-op.  Every architecture was provided with this
flush pages on architectires where ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE is
equal 1 or do nothing otherwise.

See "fix mtd_blkdevs problem with caches on some architectures" discussion
on LKML for more information.

Signed-off-by: Ilya Loginov <isloginov@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Peter Horton <phorton@bitbox.co.uk>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

This fixes up the kmap_coherent/kunmap_coherent() interface for recent
changes both in the page fault path and the shared cache flushers, as
well as adding in some optimizations.

One of the key things to note here is that the TLB flush itself is
deferred until the unmap, and the call in to update_mmu_cache() itself
goes away, relying on the regular page fault path to handle the lazy
dcache writeback if necessary.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

This does a bit of rework for making the cache flushers SMP-aware. The
function pointer-based flushers are renamed to local variants with the
exported interface being commonly implemented and wrapping as necessary.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

All CPU-specific overloads are done at runtime now, so this common header
can go away and simply be folded back in to asm/ version.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

This paves the way for allowing individual CPUs to overload the
individual flushing routines that they care about without having to
depend on weak aliases. SH-4 is converted over initially, as it wires
up pretty much everything. The majority of the other CPUs will simply use
the default no-op implementation with their own region flushers wired up.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

We use flush_cache_page() outright in copy_to_user_page(), and nothing
else needs it, so just kill it off. SH-5 still defines its own version,
but that too will go away in the same fashion once it converts over.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

All of the flush_dcache_mmap_lock()/flush_dcache_mmap_unlock()
definitions are identical across all CPUs, so just provide them
generically in asm/cacheflush.h.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

This provides a central point for CPU cache initialization routines.
This replaces the antiquated p3_cache_init() method, which the vast
majority of CPUs never cared about.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

This does a bit of reorganizing for allowing nommu to use the new
and generic cache.c, no functional changes.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

This builds in the newly created cache.c (renamed from pg-mmu.c) for both
MMU and NOMMU configurations. The kmap_coherent() stubs and alias
information recorded by each CPU family takes care of doing the right
thing while enabling the code to be commonly shared.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>