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  1. 15 11月, 2006 1 次提交
    • H
      [PATCH] hugetlb: prepare_hugepage_range check offset too · 68589bc3
      由 Hugh Dickins 提交于 
      (David:)

If hugetlbfs_file_mmap() returns a failure to do_mmap_pgoff() - for example,
because the given file offset is not hugepage aligned - then do_mmap_pgoff
will go to the unmap_and_free_vma backout path.

But at this stage the vma hasn't been marked as hugepage, and the backout path
will call unmap_region() on it.  That will eventually call down to the
non-hugepage version of unmap_page_range().  On ppc64, at least, that will
cause serious problems if there are any existing hugepage pagetable entries in
the vicinity - for example if there are any other hugepage mappings under the
same PUD.  unmap_page_range() will trigger a bad_pud() on the hugepage pud
entries.  I suspect this will also cause bad problems on ia64, though I don't
have a machine to test it on.

(Hugh:)

prepare_hugepage_range() should check file offset alignment when it checks
virtual address and length, to stop MAP_FIXED with a bad huge offset from
unmapping before it fails further down.  PowerPC should apply the same
prepare_hugepage_range alignment checks as ia64 and all the others do.

Then none of the alignment checks in hugetlbfs_file_mmap are required (nor
is the check for too small a mapping); but even so, move up setting of
VM_HUGETLB and add a comment to warn of what David Gibson discovered - if
hugetlbfs_file_mmap fails before setting it, do_mmap_pgoff's unmap_region
when unwinding from error will go the non-huge way, which may cause bad
behaviour on architectures (powerpc and ia64) which segregate their huge
mappings into a separate region of the address space.
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Acked-by: NAdam Litke <agl@us.ibm.com>
Acked-by: NDavid Gibson <david@gibson.dropbear.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      68589bc3
  3. 01 11月, 2006 1 次提交
  5. 12 10月, 2006 1 次提交
    • M
      [PATCH] mm: use symbolic names instead of indices for zone initialisation · 6391af17
      由 Mel Gorman 提交于 
      Arch-independent zone-sizing is using indices instead of symbolic names to
offset within an array related to zones (max_zone_pfns).  The unintended
impact is that ZONE_DMA and ZONE_NORMAL is initialised on powerpc instead
of ZONE_DMA and ZONE_HIGHMEM when CONFIG_HIGHMEM is set.  As a result, the
the machine fails to boot but will boot with CONFIG_HIGHMEM turned off.

The following patch properly initialises the max_zone_pfns[] array and uses
symbolic names instead of indices in each architecture using
arch-independent zone-sizing.  Two users have successfully booted their
powerpcs with it (one an ibook G4).  It has also been boot tested on x86,
x86_64, ppc64 and ia64.  Please merge for 2.6.19-rc2.

Credit to Benjamin Herrenschmidt for identifying the bug and rolling the
first fix.  Additional credit to Johannes Berg and Andreas Schwab for
reporting the problem and testing on powerpc.
Signed-off-by: NMel Gorman <mel@csn.ul.ie>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      6391af17
  7. 03 10月, 2006 1 次提交
  9. 30 9月, 2006 2 次提交
    • S
      [PATCH] pidspace: is_init() · f400e198
      由 Sukadev Bhattiprolu 提交于 
      This is an updated version of Eric Biederman's is_init() patch.
(http://lkml.org/lkml/2006/2/6/280).  It applies cleanly to 2.6.18-rc3 and
replaces a few more instances of ->pid == 1 with is_init().

Further, is_init() checks pid and thus removes dependency on Eric's other
patches for now.

Eric's original description:

	There are a lot of places in the kernel where we test for init
	because we give it special properties.  Most  significantly init
	must not die.  This results in code all over the kernel test
	->pid == 1.

	Introduce is_init to capture this case.

	With multiple pid spaces for all of the cases affected we are
	looking for only the first process on the system, not some other
	process that has pid == 1.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NSukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: <lxc-devel@lists.sourceforge.net>
Acked-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      f400e198
    • J
      [PATCH] make PROT_WRITE imply PROT_READ · df67b3da
      由 Jason Baron 提交于 
      Make PROT_WRITE imply PROT_READ for a number of architectures which don't
support write only in hardware.

While looking at this, I noticed that some architectures which do not
support write only mappings already take the exact same approach.  For
example, in arch/alpha/mm/fault.c:

"
        if (cause < 0) {
                if (!(vma->vm_flags & VM_EXEC))
                        goto bad_area;
        } else if (!cause) {
                /* Allow reads even for write-only mappings */
                if (!(vma->vm_flags & (VM_READ | VM_WRITE)))
                        goto bad_area;
        } else {
                if (!(vma->vm_flags & VM_WRITE))
                        goto bad_area;
        }
"

Thus, this patch brings other architectures which do not support write only
mappings in-line and consistent with the rest.  I've verified the patch on
ia64, x86_64 and x86.

Additional discussion:

Several architectures, including x86, can not support write-only mappings.
The pte for x86 reserves a single bit for protection and its two states are
read only or read/write.  Thus, write only is not supported in h/w.

Currently, if i 'mmap' a page write-only, the first read attempt on that page
creates a page fault and will SEGV.  That check is enforced in
arch/blah/mm/fault.c.  However, if i first write that page it will fault in
and the pte will be set to read/write.  Thus, any subsequent reads to the page
will succeed.  It is this inconsistency in behavior that this patch is
attempting to address.  Furthermore, if the page is swapped out, and then
brought back the first read will also cause a SEGV.  Thus, any arbitrary read
on a page can potentially result in a SEGV.

According to the SuSv3 spec, "if the application requests only PROT_WRITE, the
implementation may also allow read access." Also as mentioned, some
archtectures, such as alpha, shown above already take the approach that i am
suggesting.

The counter-argument to this raised by Arjan, is that the kernel is enforcing
the write only mapping the best it can given the h/w limitations.  This is
true, however Alan Cox, and myself would argue that the inconsitency in
behavior, that is applications can sometimes work/sometimes fails is highly
undesireable.  If you read through the thread, i think people, came to an
agreement on the last patch i posted, as nobody has objected to it...
Signed-off-by: NJason Baron <jbaron@redhat.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: NAndi Kleen <ak@muc.de>
Acked-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: NPaul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Ian Molton <spyro@f2s.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      df67b3da
  11. 27 9月, 2006 1 次提交
  13. 25 9月, 2006 1 次提交
  15. 25 8月, 2006 1 次提交
  17. 24 8月, 2006 1 次提交
    • A
      [POWERPC] hugepage BUG fix · c9169f87
      由 Adam Litke 提交于 
      On Tue, 2006-08-15 at 08:22 -0700, Dave Hansen wrote:
> kernel BUG in cache_free_debugcheck at mm/slab.c:2748!

Alright, this one is only triggered when slab debugging is enabled.  The
slabs are assumed to be aligned on a HUGEPTE_TABLE_SIZE boundary.  The free
path makes use of this assumption and uses the lowest nibble to pass around
an index into an array of kmem_cache pointers.  With slab debugging turned
on, the slab is still aligned, but the "working" object pointer is not.
This would break the assumption above that a full nibble is available for
the PGF_CACHENUM_MASK.

The following patch reduces PGF_CACHENUM_MASK to cover only the two least
significant bits, which is enough to cover the current number of 4 pgtable
cache types.  Then use this constant to mask out the appropriate part of
the huge pte pointer.
Signed-off-by: NAdam Litke <agl@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>
      c9169f87
  19. 08 8月, 2006 2 次提交
  21. 31 7月, 2006 1 次提交
  23. 25 7月, 2006 1 次提交
  25. 13 7月, 2006 1 次提交
  27. 07 7月, 2006 1 次提交
  29. 01 7月, 2006 1 次提交
  31. 29 6月, 2006 1 次提交
  33. 28 6月, 2006 5 次提交
  35. 27 6月, 2006 1 次提交
  37. 21 6月, 2006 1 次提交
  39. 18 6月, 2006 1 次提交
  41. 15 6月, 2006 2 次提交
    • A
      [POWERPC] Remove stale 64bit on 32bit kernel code · 227318bb
      由 Anton Blanchard 提交于 
      Remove some stale POWER3/POWER4/970 on 32bit kernel support.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>
      227318bb
    • P
      powerpc: Use 64k pages without needing cache-inhibited large pages · bf72aeba
      由 Paul Mackerras 提交于 
      Some POWER5+ machines can do 64k hardware pages for normal memory but
not for cache-inhibited pages.  This patch lets us use 64k hardware
pages for most user processes on such machines (assuming the kernel
has been configured with CONFIG_PPC_64K_PAGES=y).  User processes
start out using 64k pages and get switched to 4k pages if they use any
non-cacheable mappings.

With this, we use 64k pages for the vmalloc region and 4k pages for
the imalloc region.  If anything creates a non-cacheable mapping in
the vmalloc region, the vmalloc region will get switched to 4k pages.
I don't know of any driver other than the DRM that would do this,
though, and these machines don't have AGP.

When a region gets switched from 64k pages to 4k pages, we do not have
to clear out all the 64k HPTEs from the hash table immediately.  We
use the _PAGE_COMBO bit in the Linux PTE to indicate whether the page
was hashed in as a 64k page or a set of 4k pages.  If hash_page is
trying to insert a 4k page for a Linux PTE and it sees that it has
already been inserted as a 64k page, it first invalidates the 64k HPTE
before inserting the 4k HPTE.  The hash invalidation routines also use
the _PAGE_COMBO bit, to determine whether to look for a 64k HPTE or a
set of 4k HPTEs to remove.  With those two changes, we can tolerate a
mix of 4k and 64k HPTEs in the hash table, and they will all get
removed when the address space is torn down.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
      bf72aeba
  43. 12 6月, 2006 1 次提交
  45. 11 6月, 2006 1 次提交
  47. 09 6月, 2006 1 次提交
    • B
      [PATCH] powerpc: Fix buglet with MMU hash management · c5cf0e30
      由 Benjamin Herrenschmidt 提交于 
      Our MMU hash management code would not set the "C" bit (changed bit) in
the hardware PTE when updating a RO PTE into a RW PTE. That would cause
the hardware to possibly to a write back to the hash table to set it on
the first store access, which in addition to being a performance issue,
might also hit a bug when running with native hash management (non-HV)
as our code is specifically optimized for the case where no write back
happens.

Thus there is a very small therocial window were a hash PTE can become
corrupted if that HPTE has just been upgraded to read write, a store
access happens on it, and that races with another processor evicting
that same slot. Since eviction (caused by an almost full hash) is
extremely rare, the bug is very unlikely to happen fortunately.

This fixes by allowing the updating of the protection bits in the native
hash handling to also set (but not clear) the "C" bit, and, in order to
also improve performances in the general case, by always setting that
bit on newly inserted hash PTE so that writeback really never happens.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>
      c5cf0e30
  49. 19 5月, 2006 1 次提交
    • M
      [PATCH] powerpc: Unify mem= handling · 2babf5c2
      由 Michael Ellerman 提交于 
      We currently do mem= handling in three seperate places. And as benh pointed out
I wrote two of them. Now that we parse command line parameters earlier we can
clean this mess up.

Moving the parsing out of prom_init means the device tree might be allocated
above the memory limit. If that happens we'd have to move it. As it happens
we already have logic to do that for kdump, so just genericise it.

This also means we might have reserved regions above the memory limit, if we
do the bootmem allocator will blow up, so we have to modify
lmb_enforce_memory_limit() to truncate the reserves as well.

Tested on P5 LPAR, iSeries, F50, 44p. Tested moving device tree on P5 and
44p and F50.
Signed-off-by: NMichael Ellerman <michael@ellerman.id.au>
Signed-off-by: NPaul Mackerras <paulus@samba.org>
      2babf5c2
  51. 02 5月, 2006 1 次提交
  53. 28 4月, 2006 1 次提交
    • D
      [PATCH] powerpc: Fix pagetable bloat for hugepages · f10a04c0
      由 David Gibson 提交于 
      At present, ARCH=powerpc kernels can waste considerable space in
pagetables when making large hugepage mappings.  Hugepage PTEs go in
PMD pages, but each PMD page maps 256M and so contains only 16
hugepage PTEs (128 bytes of data), but takes up a 1024 byte
allocation.  With CONFIG_PPC_64K_PAGES enabled (64k base page size),
the situation is worse.  Now hugepage PTEs are at the PTE page level
(also mapping 256M), so we store 16 hugepage PTEs in a 64k allocation.

The PowerPC MMU already means that any 256M region is either all
hugepage, or all normal pages.  Thus, with some care, we can use a
different allocation for the hugepage PTE tables and only allocate the
128 bytes necessary.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
      f10a04c0
  55. 22 4月, 2006 2 次提交
  57. 01 4月, 2006 1 次提交
  59. 29 3月, 2006 2 次提交
  61. 28 3月, 2006 1 次提交