Presently we run in to issues with the MMU resetting the CPU when
variable sized mappings are employed. This takes a slightly more
aggressive approach to keeping the TLB and cache state sane before
establishing the mappings in order to cut down on races observed on
SMP configurations.

At the same time, we bump the VMA range up to the 0xb000...0xc000 range,
as there still seems to be some undocumented behaviour in setting up
variable mappings in the 0xa000...0xb000 range, resulting in reset by the
TLB.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

When entries are being bolted unconditionally it's possible that the boot
loader has established mappings that are within range that we don't want
to clobber. Perform some basic validation to ensure that the new mapping
is out of range before allowing the entry setup to take place.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This moves the pmb_remap_caller() mapping logic out in to
pmb_bolt_mapping(), which enables us to establish fixed mappings in
places such as the NUMA code.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This plugs in an early_param for permitting transparent PMB-backed
ioremapping to be enabled/disabled. For the time being, we use a
default-disabled policy.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This implements a fairly significant overhaul of the dynamic PMB mapping
code. The primary change here is that the PMB gets its own VMA that
follows the uncached mapping and we attempt to be a bit more intelligent
with dynamic sizing, multi-entry mapping, and so forth.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Since <linux/spinlock.h> already includes <linux/rwlock.h>, and the
latter file will warn about not having included the former file
anyway, there is no value in including rwlock.h explicitly.
Signed-off-by: NRobert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This implements a bit of rework for the PMB code, which permits us to
kill off the legacy PMB mode completely. Rather than trusting the boot
loader to do the right thing, we do a quick verification of the PMB
contents to determine whether to have the kernel setup the initial
mappings or whether it needs to mangle them later on instead.

If we're booting from legacy mappings, the kernel will now take control
of them and make them match the kernel's initial mapping configuration.
This is accomplished by breaking the initialization phase out in to
multiple steps: synchronization, merging, and resizing. With the recent
rework, the synchronization code establishes page links for compound
mappings already, so we build on top of this for promoting mappings and
reclaiming unused slots.

At the same time, the changes introduced for the uncached helpers also
permit us to dynamically resize the uncached mapping without any
particular headaches. The smallest page size is more than sufficient for
mapping all of kernel text, and as we're careful not to jump to any far
off locations in the setup code the mapping can safely be resized
regardless of whether we are executing from it or not.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

The PMB code is an example of something that spends an absurd amount of
time running uncached when only a couple of operations really need to be.
This switches over to the shiny new uncached helpers, permitting us to
spend far more time running cached.

Additionally, MMUCR twiddling is perfectly safe from cached space given
that it's paired with a control register barrier, so fix that up, too.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This implements some locking for the PMB code. A high level rwlock is
added for dealing with rw accesses on the entry map while a per-entry
data structure spinlock is added to deal with the PMB entry changing out
from underneath us.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Write-through PMB mappings still require the cache bit to be set, even if
they're to be flagged with a different cache policy and bufferability
bit. To reduce some of the confusion surrounding the flag encoding we
centralize the cache mask based on the system cache policy while we're at
it.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This plugs in entry sizing support for existing mappings and then builds
on top of that for linking together entries that are mapping contiguous
areas. This will ultimately permit us to coalesce mappings and promote
head pages while reclaiming PMB slots for dynamic remapping.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Some overdue cleanup of the PMB code, killing off unused functionality
and duplication sprinkled about the tree.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Both the store queue API and the PMB remapping take unsigned long for
their pgprot flags, which cuts off the extended protection bits. In the
case of the PMB this isn't really a problem since the cache attribute
bits that we care about are all in the lower 32-bits, but we do it just
to be safe. The store queue remapping on the other hand depends on the
extended prot bits for enabling userspace access to the mappings.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This merges the code for iterating over the legacy PMB mappings and the
code for synchronizing software state with the hardware mappings. There's
really no reason to do the same iteration twice, and this also buys us
the legacy entry logging facility for the dynamic PMB case.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

The PMB initialization code walks the entries and synchronizes the
software PMB state with the hardware mappings, preserving the slot index.
Unfortunately pmb_alloc() only tested the bit position in the entry map
and failed to set it, resulting in subsequent remaps being able to be
dynamically assigned a slot that trampled an existing boot mapping with
general badness ensuing.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

The old ctrl in/out routines are non-portable and unsuitable for
cross-platform use. While drivers/sh has already been sanitized, there
is still quite a lot of code that is not. This converts the arch/sh/ bits
over, which permits us to flag the routines as deprecated whilst still
building with -Werror for the architecture code, and to ensure that
future users are not added.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Now that cached_to_uncached works as advertized in 32-bit mode and we're
never going to be able to map < 16MB anyways, there's no need for the
special uncached section. Kill it off.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Presently __in_29bit_mode() is only defined for the PMB case, but
it's also easily derived from the CONFIG_29BIT and CONFIG_32BIT &&
CONFIG_PMB=n cases.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

More and more boards are going to start shipping that boot with the MMU
in 32BIT mode by default. Previously we relied on the bootloader to
setup PMB mappings for use by the kernel but we also need to cater for
boards whose bootloaders don't set them up.

If CONFIG_PMB_LEGACY is not enabled we have full control over our PMB
mappings and can compress our address space. Usually, the distance
between the the cached and uncached mappings of RAM is always 512MB,
however we can compress the distance to be the amount of RAM on the
board.

pmb_init() now becomes much simpler. It no longer has to calculate any
mappings, it just has to synchronise the software PMB table with the
hardware.

Tested on SDK7786 and SH7785LCR.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This introduces some much overdue chainsawing of the fixed PMB support.
fixed PMB was introduced initially to work around the fact that dynamic
PMB mode was relatively broken, though they were never intended to
converge. The main areas where there are differences are whether the
system is booted in 29-bit mode or 32-bit mode, and whether legacy
mappings are to be preserved. Any system booting in true 32-bit mode will
not care about legacy mappings, so these are roughly decoupled.

Regardless of the entry point, PMB and 32BIT are directly related as far
as the kernel is concerned, so we also switch back to having one select
the other.

With legacy mappings iterated through and applied in the initialization
path it's now possible to finally merge the two implementations and
permit dynamic remapping overtop of remaining entries regardless of
whether boot mappings are crafted by hand or inherited from the boot
loader.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

The initialisation process differs for CONFIG_PMB and for
CONFIG_PMB_FIXED. For CONFIG_PMB_FIXED we need to register the PMB
entries that were allocated by the bootloader.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

We need to map the gap between 0x00000000 and __MEMORY_START in the PMB,
as well as RAM.

With this change my 7785LCR board can switch to 32bit MMU mode at
runtime.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Eventually we'll have complete control over what physical memory gets
mapped where and we can probably do other interesting things. For now
though, when the MMU is in 32-bit mode, we map physical memory into the
P1 and P2 virtual address ranges with the same semantics as they have in
29-bit mode.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Unfortunately, at the time during in boot when we want to be setting up
the PMB entries, the kmem subsystem hasn't been initialised.

We now match pmb_map slots with pmb_entry_list slots. When we find an
empty slot in pmb_map, we set the bit, thereby acquiring the
corresponding pmb_entry_list entry. There is a benefit in using this
static array of struct pmb_entry's; we don't need to acquire any locks
in order to traverse the list of struct pmb_entry's.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

There's no need to export the internal PMB functions for allocating,
freeing and modifying PMB entries, etc. This way we can restrict the
interface for PMB.

Also remove the static from pmb_init() so that we have more freedom in
setting up the initial PMB entries and turning on MMU 32bit mode.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Simplify set_pmb_entry() by removing the possibility of not finding a
free slot in the PMB. Instead we now allocate a slot in pmb_alloc() so
that if there are no free slots we fail at allocation time, rather than
in set_pmb_entry().
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Currently, we've got the less than ideal situation where if we need to
allocate a 256MB mapping we'll allocate four entries like so,

	 entry 1: 128MB
	 entry 2:  64MB
	 entry 3:  16MB
	 entry 4:  16MB

This is because as we execute the loop in pmb_remap() we will
progressively try mapping the remaining address space with smaller and
smaller sizes. This isn't good because the size we use on one iteration
may be the perfect size to use on the next iteration, for instance when
the initial size is divisible by one of the PMB mapping sizes.

With this patch, we now only need two entries in the PMB to map 256MB of
address space,

	  entry 1: 128MB
	  entry 2: 128MB
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

If we fail to allocate a PMB entry in pmb_remap() we must remember to
clear and free any PMB entries that we may have previously allocated,
e.g. if we were allocating a multiple entry mapping.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This implements preliminary suspend/resume support for the PMB.
Signed-off-by: NFrancesco Virlinzi <francesco.virlinzi@st.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

debugfs_create_file() returns NULL if an error occurs, returns -ENODEV
when debugfs is not enabled in the kernel.
Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

When using single_open(), single_release() should be used instead
of seq_release(), otherwise there is a memory leak.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Kmem cache passed to constructor is only needed for constructors that are
themselves multiplexeres.  Nobody uses this "feature", nor does anybody uses
passed kmem cache in non-trivial way, so pass only pointer to object.

Non-trivial places are:
	arch/powerpc/mm/init_64.c
	arch/powerpc/mm/hugetlbpage.c

This is flag day, yes.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Acked-by: NPekka Enberg <penberg@cs.helsinki.fi>
Acked-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Jon Tollefson <kniht@linux.vnet.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Matt Mackall <mpm@selenic.com>
[akpm@linux-foundation.org: fix arch/powerpc/mm/hugetlbpage.c]
[akpm@linux-foundation.org: fix mm/slab.c]
[akpm@linux-foundation.org: fix ubifs]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NPaul 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: NStuart Menefy <stuart.menefy@st.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Signed-off-by: NNobuhiro Iwamatsu <iwamatsu@nigauri.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Signed-off-by: NStuart Menefy <stuart.menefy@st.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Slab constructors currently have a flags parameter that is never used.  And
the order of the arguments is opposite to other slab functions.  The object
pointer is placed before the kmem_cache pointer.

Convert

        ctor(void *object, struct kmem_cache *s, unsigned long flags)

to

        ctor(struct kmem_cache *s, void *object)

throughout the kernel

[akpm@linux-foundation.org: coupla fixes]
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This reworks the cache mode configuration in Kconfig, and allows for
explicit selection of write-back/write-through/off configurations.
All of the cache flushing routines are optimized away for the off
case.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Slab destructors were no longer supported after Christoph's
c59def9f change. They've been
BUGs for both slab and slub, and slob never supported them
either.

This rips out support for the dtor pointer from kmem_cache_create()
completely and fixes up every single callsite in the kernel (there were
about 224, not including the slab allocator definitions themselves,
or the documentation references).
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This is the last remaining slab destructor in the kernel, which
we kill off and move the resultant list tracking logic up to
the pmb_alloc()/pmb_free() paths.

As Christoph Lameter pointed out, it's potentially unsafe to be
taking the list lock in the destructor anyways, so this is also
more fundamentally correct.

With this in place, we're all set for killing off slab destructors
from the kernel entirely.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>