This is a pure documentation, to try to explain why the cache flushing code
for the SH4 is implemented the way it is.
Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This uses jump_to_uncached() which is now given the noinline attribute
due to the special section mapping. Kill off the inline attribute to
fix up compilation failure.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Add implementation of flush_icache_range() suitable for signal handler
and kprobes. Remove flush_cache_sigtramp() and change signal.c to use
flush_icache_range().
Signed-off-by: Chris Smith <chris.smith@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Presently most of the 29-bit physical parts do P1/P2 segmentation
with a 1:1 cached/uncached mapping, jumping between the two to
control the caching behaviour. This provides the basic infrastructure
to maintain this behaviour on 32-bit physical parts that don't map
P1/P2 at all, using a shiny new linker section and corresponding
fixmap entry.
Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Calculate the number of cache aliases on probed L2 caches, and while
we're at it, print out the detected statistics at boot time for these
also.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
There was an off-by-1 on the cache alias detection logic on SH-4,
which caused n_aliases to always be 1 even when the page size
precluded the existence of aliases.
With this corrected, 64KB pages happily reports n_aliases == 0, and
hits the appropriate fast paths in the flushing routines.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
current_cpu_data uses smp_processor_id() in order to find the
corresponding cpu_data. As the cache descs are all currently
identical, just have this look at probed results from the boot
CPU.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
The first 1MB of P3 space was reserved and used for page colouring,
as we've reworked that to use fixmaps, we can reclaim the space and
hand it back to VMALLOC_START.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This wires up kmap_coherent() and kunmap_coherent() on SH-4, and
moves away from the p3map_mutex and reserved P3 space, opting to
use fixmaps for colouring instead.
The copy_user_page()/clear_user_page() implementations are moved
to this, which fixes the nasty blowups with spinlock debugging
as a result of having some of these calls nested under the page
table lock.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
There are a lot of bogus cpu_data-> references that only end up working
for the boot CPU, convert these to current_cpu_data to fixup SMP.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This converts the lazy dcache handling to the model described in
Documentation/cachetlb.txt and drops the ptep_get_and_clear() hacks
used for the aliasing dcaches on SH-4 and SH7705 in 32kB mode. As a
bonus, this slightly cuts down on the cache flushing frequency.
With that and the PTEA handling out of the way, the update_mmu_cache()
implementations can be consolidated, and we no longer have to worry
about which configuration the cache is in for the SH7705 case.
And finally, explicitly disable the lazy writeback on SMP (SH-4A).
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
There were a number of places that made evil PAGE_SIZE == 4k
assumptions that ended up breaking when trying to play with
8k and 64k page sizes, this fixes those up.
The most significant change is the way we load THREAD_SIZE,
previously this was done via:
mov #(THREAD_SIZE >> 8), reg
shll8 reg
to avoid a memory access and allow the immediate load. With
a 64k PAGE_SIZE, we're out of range for the immediate load
size without resorting to special instructions available in
later ISAs (movi20s and so on). The "workaround" for this is
to bump up the shift to 10 and insert a shll2, which gives a
bit more flexibility while still being much cheaper than a
memory access.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
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: Takeo Takahashi <takahashi.takeo@renesas.com>
Signed-off-by: Paul 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: Paul 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: Paul 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: Richard Curnow <richard.curnow@st.com>
Signed-off-by: Paul 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: Paul Mundt <lethal@linux-sh.org>
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!
