Background: I've implemented 1K/2K page tables for s390.  These sub-page
page tables are required to properly support the s390 virtualization
instruction with KVM.  The SIE instruction requires that the page tables
have 256 page table entries (pte) followed by 256 page status table entries
(pgste).  The pgstes are only required if the process is using the SIE
instruction.  The pgstes are updated by the hardware and by the hypervisor
for a number of reasons, one of them is dirty and reference bit tracking.
To avoid wasting memory the standard pte table allocation should return
1K/2K (31/64 bit) and 2K/4K if the process is using SIE.

Problem: Page size on s390 is 4K, page table size is 1K or 2K.  That means
the s390 version for pte_alloc_one cannot return a pointer to a struct
page.  Trouble is that with the CONFIG_HIGHPTE feature on x86 pte_alloc_one
cannot return a pointer to a pte either, since that would require more than
32 bit for the return value of pte_alloc_one (and the pte * would not be
accessible since its not kmapped).

Solution: The only solution I found to this dilemma is a new typedef: a
pgtable_t.  For s390 pgtable_t will be a (pte *) - to be introduced with a
later patch.  For everybody else it will be a (struct page *).  The
additional problem with the initialization of the ptl lock and the
NR_PAGETABLE accounting is solved with a constructor pgtable_page_ctor and
a destructor pgtable_page_dtor.  The page table allocation and free
functions need to call these two whenever a page table page is allocated or
freed.  pmd_populate will get a pgtable_t instead of a struct page pointer.
 To get the pgtable_t back from a pmd entry that has been installed with
pmd_populate a new function pmd_pgtable is added.  It replaces the pmd_page
call in free_pte_range and apply_to_pte_range.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

asm/elf.h, asm/page.h and asm/user.h don't export to userspace now, so we can
drop #ifdef __KERNEL__ for them.

[k.shutemov@gmail.com: remove #ifdef __KERNEL_]
Signed-off-by: NKirill A. Shutemov <k.shutemov@gmail.com>
Reviewed-by: NDavid Woodhouse <dwmw2@infradead.org>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: NKirill A. Shutemov <k.shutemov@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We have the macro _AC() generally available now
so the calculation of PAGE_SIZE can be made
assembler compatible.
Introduce use of _AC() and kill all users of
ASM_PAGE_SIZE.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NKyle McMartin <kyle@mcmartin.ca>

Signed-off-by: NHelge Deller <deller@gmx.de>
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

This patch fixes the pa8800 at a gross level (there are still other
subtle incoherency issues which can still cause crashes and HPMCs).

What it does is try to force eject inequivalent aliases before they
become visible to the L2 cache (which is where we get the incoherence
problems).

A new function (parisc_requires_coherency) is introduced in
asm/processor.h to identify the pa8x00 processors (8800 and 8900)
which have the issue.
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

Remove definitions of PAGE_* from the user view
Delete unnecessary comments referring to the size of pages
Only include <asm-generic> if we're in __KERNEL__
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>
Signed-off-by: NMatthew Wilcox <matthew@wil.cx>
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

More work towards supporing multiple page sizes on 64-bit. Convert
some assumptions that 64bit uses 3 level page tables into testing
PT_NLEVELS. Also some BUG() to BUG_ON() conversions and some cleanups
to assembler.
Signed-off-by: NHelge Deller <deller@parisc-linux.org>
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

Add STRICT_MM_TYPECHECKS to page.h as other architectures do.
Signed-off-by: NHelge Deller <deller@parisc-linux.org>
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

We need to do a little renaming of our original syntax because
of the difference in arguments.
Signed-off-by: NJames Bottomley <jejb@parisc-linux.org>
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

PARISC can use generic funcs.
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Define some constants for HugeTLB pages, not that parisc-linux supports
it yet.
Signed-off-by: NHelge Deller <deller@parisc-linux.org>
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

Someone mentioned that almost all the architectures used basically the same
implementation of get_order.  This patch consolidates them into
asm-generic/page.h and includes that in the appropriate places.  The
exceptions are ia64 and ppc which have their own (presumably optimised)
versions.
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.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!