linux.git/include/asm-powerpc/pgtable-ppc64.h, branch v2.6.26

Correct hash flushing from huge_ptep_set_wrprotect()

2008-07-08T16:27:58+00:00

As Andy Whitcroft recently pointed out, the current powerpc version of
huge_ptep_set_wrprotect() has a bug.  It just calls ptep_set_wrprotect()
which in turn calls pte_update() then hpte_need_flush() with the 'huge'
argument set to 0.  This will cause hpte_need_flush() to flush the wrong
hash entries (of any).  Andy's fix for this is already in the powerpc
tree as commit 016b33c4958681c24056abed8ec95844a0da80a3.

I have confirmed this is a real bug, not masked by some other
synchronization, with a new testcase for libhugetlbfs.  A process write
a (MAP_PRIVATE) hugepage mapping, fork(), then alter the mapping and
have the child incorrectly see the second write.

Therefore, this should be fixed for 2.6.26, and for the stable tree.
Here is a suitable patch for 2.6.26, which I think will also be suitable
for the stable tree (neither of the headers in question has been changed
much recently).

It is cut down slighlty from Andy's original version, in that it does
not include a 32-bit version of huge_ptep_set_wrprotect().  Currently,
hugepages are not supported on any 32-bit powerpc platform.  When they
are, a suitable 32-bit version can be added - the only 32-bit hardware
which supports hugepages does not use the conventional hashtable MMU and
so will have different needs anyway.

Signed-off-by: Andy Whitcroft 
Signed-off-by: David Gibson 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Linus Torvalds

[POWERPC] vmemmap fixes to use smaller pages

2008-05-15T10:49:25+00:00

This changes vmemmap to use a different region (region 0xf) of the
address space, and to configure the page size of that region
dynamically at boot.

The problem with the current approach of always using 16M pages is that
it's not well suited to machines that have small amounts of memory such
as small partitions on pseries, or PS3's.

In fact, on the PS3, failure to allocate the 16M page backing vmmemmap
tends to prevent hotplugging the HV's "additional" memory, thus limiting
the available memory even more, from my experience down to something
like 80M total, which makes it really not very useable.

The logic used by my match to choose the vmemmap page size is:

 - If 16M pages are available and there's 1G or more RAM at boot,
   use that size.
 - Else if 64K pages are available, use that
 - Else use 4K pages

I've tested on a POWER6 (16M pages) and on an iSeries POWER3 (4K pages)
and it seems to work fine.

Note that I intend to change the way we organize the kernel regions &
SLBs so the actual region will change from 0xf back to something else at
one point, as I simplify the SLB miss handler, but that will be for a
later patch.

Signed-off-by: Paul Mackerras

mm: introduce pte_special pte bit

2008-04-28T15:58:23+00:00

s390 for one, cannot implement VM_MIXEDMAP with pfn_valid, due to their memory
model (which is more dynamic than most).  Instead, they had proposed to
implement it with an additional path through vm_normal_page(), using a bit in
the pte to determine whether or not the page should be refcounted:

vm_normal_page()
{
	...
        if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
                if (vma->vm_flags & VM_MIXEDMAP) {
#ifdef s390
			if (!mixedmap_refcount_pte(pte))
				return NULL;
#else
                        if (!pfn_valid(pfn))
                                return NULL;
#endif
                        goto out;
                }
	...
}

This is fine, however if we are allowed to use a bit in the pte to determine
refcountedness, we can use that to _completely_ replace all the vma based
schemes.  So instead of adding more cases to the already complex vma-based
scheme, we can have a clearly seperate and simple pte-based scheme (and get
slightly better code generation in the process):

vm_normal_page()
{
#ifdef s390
	if (!mixedmap_refcount_pte(pte))
		return NULL;
	return pte_page(pte);
#else
	...
#endif
}

And finally, we may rather make this concept usable by any architecture rather
than making it s390 only, so implement a new type of pte state for this.
Unfortunately the old vma based code must stay, because some architectures may
not be able to spare pte bits.  This makes vm_normal_page a little bit more
ugly than we would like, but the 2 cases are clearly seperate.

So introduce a pte_special pte state, and use it in mm/memory.c.  It is
currently a noop for all architectures, so this doesn't actually result in any
compiled code changes to mm/memory.o.

BTW:
I haven't put vm_normal_page() into arch code as-per an earlier suggestion.
The reason is that, regardless of where vm_normal_page is actually
implemented, the *abstraction* is still exactly the same. Also, while it
depends on whether the architecture has pte_special or not, that is the
only two possible cases, and it really isn't an arch specific function --
the role of the arch code should be to provide primitive functions and
accessors with which to build the core code; pte_special does that. We do
not want architectures to know or care about vm_normal_page itself, and
we definitely don't want them being able to invent something new there
out of sight of mm/ code. If we made vm_normal_page an arch function, then
we have to make vm_insert_mixed (next patch) an arch function too. So I
don't think moving it to arch code fundamentally improves any abstractions,
while it does practically make the code more difficult to follow, for both
mm and arch developers, and easier to misuse.

[akpm@linux-foundation.org: build fix]
Signed-off-by: Nick Piggin 
Acked-by: Carsten Otte 
Cc: Jared Hulbert 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ppc64: SPARSEMEM_VMEMMAP support

2007-10-16T16:42:51+00:00

Enable virtual memmap support for SPARSEMEM on PPC64 systems.  Slice a 16th
off the end of the linear mapping space and use that to hold the vmemmap.
Uses the same size mapping as uses in the linear 1:1 kernel mapping.

[pbadari@gmail.com: fix warning]
Signed-off-by: Andy Whitcroft 
Acked-by: Mel Gorman 
Cc: Christoph Lameter 
Cc: Paul Mackerras 
Cc: Benjamin Herrenschmidt 
Cc: KAMEZAWA Hiroyuki 
Signed-off-by: Badari Pulavarty 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: remove ptep_test_and_clear_dirty and ptep_clear_flush_dirty

2007-07-17T17:22:59+00:00

Nobody is using ptep_test_and_clear_dirty and ptep_clear_flush_dirty.  Remove
the functions from all architectures.

Signed-off-by: Martin Schwidefsky 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc

2007-07-17T00:58:08+00:00

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc: (209 commits)
  [POWERPC] Create add_rtc() function to enable the RTC CMOS driver
  [POWERPC] Add H_ILLAN_ATTRIBUTES hcall number
  [POWERPC] xilinxfb: Parameterize xilinxfb platform device registration
  [POWERPC] Oprofile support for Power 5++
  [POWERPC] Enable arbitary speed tty ioctls and split input/output speed
  [POWERPC] Make drivers/char/hvc_console.c:khvcd() static
  [POWERPC] Remove dead code for preventing pread() and pwrite() calls
  [POWERPC] Remove unnecessary #undef printk from prom.c
  [POWERPC] Fix typo in Ebony default DTS
  [POWERPC] Check for NULL ppc_md.init_IRQ() before calling
  [POWERPC] Remove extra return statement
  [POWERPC] pasemi: Don't auto-select CONFIG_EMBEDDED
  [POWERPC] pasemi: Rename platform
  [POWERPC] arch/powerpc/kernel/sysfs.c: Move NUMA exports
  [POWERPC] Add __read_mostly support for powerpc
  [POWERPC] Modify sched_clock() to make CONFIG_PRINTK_TIME more sane
  [POWERPC] Create a dummy zImage if no valid platform has been selected
  [POWERPC] PS3: Bootwrapper support.
  [POWERPC] powermac i2c: Use mutex
  [POWERPC] Schedule removal of arch/ppc
  ...

Fixed up conflicts manually in:

	Documentation/feature-removal-schedule.txt
	arch/powerpc/kernel/pci_32.c
	arch/powerpc/kernel/pci_64.c
	include/asm-powerpc/pci.h

and asked the powerpc people to double-check the result..

page table handling cleanup

2007-07-16T16:05:36+00:00

Kill pte_rdprotect(), pte_exprotect(), pte_mkread(), pte_mkexec(), pte_read(),
pte_exec(), and pte_user() except where arch-specific code is making use of
them.

Signed-off-by: Jan Beulich 
Cc: Andi Kleen 
Cc: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'for-2.6.23' into merge

2007-07-11T03:28:26+00:00

Rework ptep_set_access_flags and fix sun4c

2007-06-16T20:16:16+00:00

Some changes done a while ago to avoid pounding on ptep_set_access_flags and
update_mmu_cache in some race situations break sun4c which requires
update_mmu_cache() to always be called on minor faults.

This patch reworks ptep_set_access_flags() semantics, implementations and
callers so that it's now responsible for returning whether an update is
necessary or not (basically whether the PTE actually changed).  This allow
fixing the sparc implementation to always return 1 on sun4c.

[akpm@linux-foundation.org: fixes, cleanups]
Signed-off-by: Benjamin Herrenschmidt 
Cc: Hugh Dickins 
Cc: David Miller 
Cc: Mark Fortescue 
Acked-by: William Lee Irwin III 
Cc: "Luck, Tony" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[POWERPC] Start factoring pgtable-ppc32.h and pgtable-ppc64.h

2007-06-14T12:30:15+00:00

This factors some things defined in both pgtable-ppc32.h and
pgtable-ppc64.h into the common part of asm-powerpc/pgtable.h.  These
are all things which have essentially identical definitions, and which
by their nature are very unlikely ever to need different definitions
in the two cases.

Signed-off-by: David Gibson 
Signed-off-by: Paul Mackerras