10 Jun, 2009

1 commit

  • With the "security: use mmap_min_addr indepedently of security models"
    change, mmap_min_addr is used in common areas, which susbsequently blows
    up the nommu build. This stubs in the definition in the nommu case as
    well.

    Signed-off-by: Paul Mundt

    --

    mm/nommu.c | 3 +++
    1 file changed, 3 insertions(+)
    Signed-off-by: James Morris

    Paul Mundt
     

08 May, 2009

1 commit


07 May, 2009

1 commit

  • NOMMU mmap() has an option controlled by a sysctl variable that determines
    whether the allocations made by do_mmap_private() should have the excess
    space trimmed off and returned to the allocator. Make the initial setting
    of this variable a Kconfig configuration option.

    The reason there can be excess space is that the allocator only allocates
    in power-of-2 size chunks, but mmap()'s can be made in sizes that aren't a
    power of 2.

    There are two alternatives:

    (1) Keep the excess as dead space. The dead space then remains unused for the
    lifetime of the mapping. Mappings of shared objects such as libc, ld.so
    or busybox's text segment may retain their dead space forever.

    (2) Return the excess to the allocator. This means that the dead space is
    limited to less than a page per mapping, but it means that for a transient
    process, there's more chance of fragmentation as the excess space may be
    reused fairly quickly.

    During the boot process, a lot of transient processes are created, and
    this can cause a lot of fragmentation as the pagecache and various slabs
    grow greatly during this time.

    By turning off the trimming of excess space during boot and disabling
    batching of frees, Coldfire can manage to boot.

    A better way of doing things might be to have /sbin/init turn this option
    off. By that point libc, ld.so and init - which are all long-duration
    processes - have all been loaded and trimmed.

    Reported-by: Lanttor Guo
    Signed-off-by: David Howells
    Tested-by: Lanttor Guo
    Cc: Greg Ungerer
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    David Howells
     

03 May, 2009

1 commit

  • The Committed_AS field can underflow in certain situations:

    > # while true; do cat /proc/meminfo | grep _AS; sleep 1; done | uniq -c
    > 1 Committed_AS: 18446744073709323392 kB
    > 11 Committed_AS: 18446744073709455488 kB
    > 6 Committed_AS: 35136 kB
    > 5 Committed_AS: 18446744073709454400 kB
    > 7 Committed_AS: 35904 kB
    > 3 Committed_AS: 18446744073709453248 kB
    > 2 Committed_AS: 34752 kB
    > 9 Committed_AS: 18446744073709453248 kB
    > 8 Committed_AS: 34752 kB
    > 3 Committed_AS: 18446744073709320960 kB
    > 7 Committed_AS: 18446744073709454080 kB
    > 3 Committed_AS: 18446744073709320960 kB
    > 5 Committed_AS: 18446744073709454080 kB
    > 6 Committed_AS: 18446744073709320960 kB

    Because NR_CPUS can be greater than 1000 and meminfo_proc_show() does
    not check for underflow.

    But NR_CPUS proportional isn't good calculation. In general,
    possibility of lock contention is proportional to the number of online
    cpus, not theorical maximum cpus (NR_CPUS).

    The current kernel has generic percpu-counter stuff. using it is right
    way. it makes code simplify and percpu_counter_read_positive() don't
    make underflow issue.

    Reported-by: Dave Hansen
    Signed-off-by: KOSAKI Motohiro
    Cc: Eric B Munson
    Cc: Mel Gorman
    Cc: Christoph Lameter
    Cc: [All kernel versions]
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    KOSAKI Motohiro
     

03 Apr, 2009

1 commit

  • Fix a number of issues with the per-MM VMA patch:

    (1) Make mmap_pages_allocated an atomic_long_t, just in case this is used on
    a NOMMU system with more than 2G pages. Makes no difference on a 32-bit
    system.

    (2) Report vma->vm_pgoff * PAGE_SIZE as a 64-bit value, not a 32-bit value,
    lest it overflow.

    (3) Move the allocation of the vm_area_struct slab back for fork.c.

    (4) Use KMEM_CACHE() for both vm_area_struct and vm_region slabs.

    (5) Use BUG_ON() rather than if () BUG().

    (6) Make the default validate_nommu_regions() a static inline rather than a
    #define.

    (7) Make free_page_series()'s objection to pages with a refcount != 1 more
    informative.

    (8) Adjust the __put_nommu_region() banner comment to indicate that the
    semaphore must be held for writing.

    (9) Limit the number of warnings about munmaps of non-mmapped regions.

    Reported-by: Andrew Morton
    Signed-off-by: David Howells
    Cc: Greg Ungerer
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    David Howells
     

27 Jan, 2009

1 commit


21 Jan, 2009

1 commit


14 Jan, 2009

2 commits


08 Jan, 2009

4 commits

  • Now that we no longer use compound pages for all large allocations,
    kobjsize() actively breaks things like binfmt_flat by always handing
    back PAGE_SIZE for mmap'ed regions. Fix this up by looking up the
    VMA region for non-compounds.

    Ideally binfmt_flat wants to get rid of kobjsize() completely, but
    this is an incremental step.

    Signed-off-by: Paul Mundt
    Signed-off-by: David Howells
    Tested-by: Mike Frysinger

    Paul Mundt
     
  • NOMMU mmap allocates a piece of memory for an mmap that's rounded up in size to
    the nearest power-of-2 number of pages. Currently it then discards the excess
    pages back to the page allocator, making that memory available for use by other
    things. This can, however, cause greater amount of fragmentation.

    To counter this, a sysctl is added in order to fine-tune the trimming
    behaviour. The default behaviour remains to trim pages aggressively, while
    this can either be disabled completely or set to a higher page-granular
    watermark in order to have finer-grained control.

    vm region vm_top bits taken from an earlier patch by David Howells.

    Signed-off-by: Paul Mundt
    Signed-off-by: David Howells
    Tested-by: Mike Frysinger

    Paul Mundt
     
  • Make VMAs per mm_struct as for MMU-mode linux. This solves two problems:

    (1) In SYSV SHM where nattch for a segment does not reflect the number of
    shmat's (and forks) done.

    (2) In mmap() where the VMA's vm_mm is set to point to the parent mm by an
    exec'ing process when VM_EXECUTABLE is specified, regardless of the fact
    that a VMA might be shared and already have its vm_mm assigned to another
    process or a dead process.

    A new struct (vm_region) is introduced to track a mapped region and to remember
    the circumstances under which it may be shared and the vm_list_struct structure
    is discarded as it's no longer required.

    This patch makes the following additional changes:

    (1) Regions are now allocated with alloc_pages() rather than kmalloc() and
    with no recourse to __GFP_COMP, so the pages are not composite. Instead,
    each page has a reference on it held by the region. Anything else that is
    interested in such a page will have to get a reference on it to retain it.
    When the pages are released due to unmapping, each page is passed to
    put_page() and will be freed when the page usage count reaches zero.

    (2) Excess pages are trimmed after an allocation as the allocation must be
    made as a power-of-2 quantity of pages.

    (3) VMAs are added to the parent MM's R/B tree and mmap lists. As an MM may
    end up with overlapping VMAs within the tree, the VMA struct address is
    appended to the sort key.

    (4) Non-anonymous VMAs are now added to the backing inode's prio list.

    (5) Holes may be punched in anonymous VMAs with munmap(), releasing parts of
    the backing region. The VMA and region structs will be split if
    necessary.

    (6) sys_shmdt() only releases one attachment to a SYSV IPC shared memory
    segment instead of all the attachments at that addresss. Multiple
    shmat()'s return the same address under NOMMU-mode instead of different
    virtual addresses as under MMU-mode.

    (7) Core dumping for ELF-FDPIC requires fewer exceptions for NOMMU-mode.

    (8) /proc/maps is now the global list of mapped regions, and may list bits
    that aren't actually mapped anywhere.

    (9) /proc/meminfo gains a line (tagged "MmapCopy") that indicates the amount
    of RAM currently allocated by mmap to hold mappable regions that can't be
    mapped directly. These are copies of the backing device or file if not
    anonymous.

    These changes make NOMMU mode more similar to MMU mode. The downside is that
    NOMMU mode requires some extra memory to track things over NOMMU without this
    patch (VMAs are no longer shared, and there are now region structs).

    Signed-off-by: David Howells
    Tested-by: Mike Frysinger
    Acked-by: Paul Mundt

    David Howells
     
  • Delete the askedalloc and realalloc variables as nothing actually uses the
    value calculated.

    Signed-off-by: David Howells
    Tested-by: Mike Frysinger
    Acked-by: Paul Mundt

    David Howells
     

06 Jan, 2009

1 commit

  • We used to have rather schizophrenic set of checks for NULL ->i_op even
    though it had been eliminated years ago. You'd need to go out of your
    way to set it to NULL explicitly _and_ a bunch of code would die on
    such inodes anyway. After killing two remaining places that still
    did that bogosity, all that crap can go away.

    Signed-off-by: Al Viro

    Al Viro
     

31 Oct, 2008

1 commit

  • Junjiro R. Okajima reported a problem where knfsd crashes if you are
    using it to export shmemfs objects and run strict overcommit. In this
    situation the current->mm based modifier to the overcommit goes through a
    NULL pointer.

    We could simply check for NULL and skip the modifier but we've caught
    other real bugs in the past from mm being NULL here - cases where we did
    need a valid mm set up (eg the exec bug about a year ago).

    To preserve the checks and get the logic we want shuffle the checking
    around and add a new helper to the vm_ security wrappers

    Also fix a current->mm reference in nommu that should use the passed mm

    [akpm@linux-foundation.org: coding-style fixes]
    [akpm@linux-foundation.org: fix build]
    Reported-by: Junjiro R. Okajima
    Acked-by: James Morris
    Signed-off-by: Alan Cox
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Alan Cox
     

20 Oct, 2008

1 commit

  • Make sure that mlocked pages also live on the unevictable LRU, so kswapd
    will not scan them over and over again.

    This is achieved through various strategies:

    1) add yet another page flag--PG_mlocked--to indicate that
    the page is locked for efficient testing in vmscan and,
    optionally, fault path. This allows early culling of
    unevictable pages, preventing them from getting to
    page_referenced()/try_to_unmap(). Also allows separate
    accounting of mlock'd pages, as Nick's original patch
    did.

    Note: Nick's original mlock patch used a PG_mlocked
    flag. I had removed this in favor of the PG_unevictable
    flag + an mlock_count [new page struct member]. I
    restored the PG_mlocked flag to eliminate the new
    count field.

    2) add the mlock/unevictable infrastructure to mm/mlock.c,
    with internal APIs in mm/internal.h. This is a rework
    of Nick's original patch to these files, taking into
    account that mlocked pages are now kept on unevictable
    LRU list.

    3) update vmscan.c:page_evictable() to check PageMlocked()
    and, if vma passed in, the vm_flags. Note that the vma
    will only be passed in for new pages in the fault path;
    and then only if the "cull unevictable pages in fault
    path" patch is included.

    4) add try_to_unlock() to rmap.c to walk a page's rmap and
    ClearPageMlocked() if no other vmas have it mlocked.
    Reuses as much of try_to_unmap() as possible. This
    effectively replaces the use of one of the lru list links
    as an mlock count. If this mechanism let's pages in mlocked
    vmas leak through w/o PG_mlocked set [I don't know that it
    does], we should catch them later in try_to_unmap(). One
    hopes this will be rare, as it will be relatively expensive.

    Original mm/internal.h, mm/rmap.c and mm/mlock.c changes:
    Signed-off-by: Nick Piggin

    splitlru: introduce __get_user_pages():

    New munlock processing need to GUP_FLAGS_IGNORE_VMA_PERMISSIONS.
    because current get_user_pages() can't grab PROT_NONE pages theresore it
    cause PROT_NONE pages can't munlock.

    [akpm@linux-foundation.org: fix this for pagemap-pass-mm-into-pagewalkers.patch]
    [akpm@linux-foundation.org: untangle patch interdependencies]
    [akpm@linux-foundation.org: fix things after out-of-order merging]
    [hugh@veritas.com: fix page-flags mess]
    [lee.schermerhorn@hp.com: fix munlock page table walk - now requires 'mm']
    [kosaki.motohiro@jp.fujitsu.com: build fix]
    [kosaki.motohiro@jp.fujitsu.com: fix truncate race and sevaral comments]
    [kosaki.motohiro@jp.fujitsu.com: splitlru: introduce __get_user_pages()]
    Signed-off-by: KOSAKI Motohiro
    Signed-off-by: Rik van Riel
    Signed-off-by: Lee Schermerhorn
    Cc: Nick Piggin
    Cc: Dave Hansen
    Cc: Matt Mackall
    Signed-off-by: Hugh Dickins
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     

04 Aug, 2008

1 commit

  • Now that SH has switched to vmalloc_exec() for PAGE_KERNEL_EXEC usage,
    it's apparent that nommu has no vmalloc_exec() definition of its own.
    Stub in the one from mm/vmalloc.c.

    Signed-off-by: Paul Mundt

    Paul Mundt
     

27 Jul, 2008

1 commit

  • This adds tracehook_expect_breakpoints() as a formal hook for the nommu
    code to use for its, "Is text-poking likely?" check at mmap time. This
    names the actual semantics the code means to test, and documents it.

    Signed-off-by: Roland McGrath
    Cc: Oleg Nesterov
    Reviewed-by: Ingo Molnar
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Roland McGrath
     

12 Jun, 2008

1 commit

  • This implements a few changes on top of the recent kobjsize() refactoring
    introduced by commit 6cfd53fc03670c7a544a56d441eb1a6cc800d72b.

    As Christoph points out:

    virt_to_head_page cannot return NULL. virt_to_page also
    does not return NULL. pfn_valid() needs to be used to
    figure out if a page is valid. Otherwise the page struct
    reference that was returned may have PageReserved() set
    to indicate that it is not a valid page.

    As discussed further in the thread, virt_addr_valid() is the preferable
    way to validate the object pointer in this case. In addition to fixing
    up the reserved page case, it also has the benefit of encapsulating the
    hack introduced by commit 4016a1390d07f15b267eecb20e76a48fd5c524ef on
    the impacted platforms, allowing us to get rid of the extra checking in
    kobjsize() for the platforms that don't perform this type of bizarre
    memory_end abuse (every nommu platform that isn't blackfin). If blackfin
    decides to get in line with every other platform and use PageReserved
    for the DMA pages in question, kobjsize() will also continue to work
    fine.

    It also turns out that compound_order() will give us back 0-order for
    non-head pages, so we can get rid of the PageCompound check and just
    use compound_order() directly. Clean that up while we're at it.

    Signed-off-by: Paul Mundt
    Reviewed-by: Christoph Lameter
    Acked-by: David Howells
    Signed-off-by: Linus Torvalds

    Paul Mundt
     

07 Jun, 2008

1 commit

  • kobjsize() has been abusing page->index as a method for sorting out
    compound order, which blows up both for page cache pages, and SLOB's
    reuse of the index in struct slob_page.

    Presently we are not able to accurately size arbitrary pointers that
    don't come from kmalloc(), so the best we can do is sort out the
    compound order from the head page if it's a compound page, or default
    to 0-order if it's impossible to ksize() the object.

    Obviously this leaves quite a bit to be desired in terms of object
    sizing accuracy, but the behaviour is unchanged over the existing
    implementation, while fixing the page->index oopses originally reported
    here:

    http://marc.info/?l=linux-mm&m=121127773325245&w=2

    Accuracy could also be improved by having SLUB and SLOB both set PG_slab
    on ksizeable pages, rather than just handling the __GFP_COMP cases
    irregardless of the PG_slab setting, as made possibly with Pekka's
    patches:

    http://marc.info/?l=linux-kernel&m=121139439900534&w=2
    http://marc.info/?l=linux-kernel&m=121139440000537&w=2
    http://marc.info/?l=linux-kernel&m=121139440000540&w=2

    This is primarily a bugfix for nommu systems for 2.6.26, with the aim
    being to gradually kill off kobjsize() and its particular brand of
    object abuse entirely.

    Reviewed-by: Pekka Enberg
    Signed-off-by: Paul Mundt
    Acked-by: David Howells
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Paul Mundt
     

25 May, 2008

1 commit

  • The atomic_t type is 32bit but a 64bit system can have more than 2^32
    pages of virtual address space available. Without this we overflow on
    ludicrously large mappings

    Signed-off-by: Alan Cox
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Alan Cox
     

29 Apr, 2008

1 commit

  • The kernel implements readlink of /proc/pid/exe by getting the file from
    the first executable VMA. Then the path to the file is reconstructed and
    reported as the result.

    Because of the VMA walk the code is slightly different on nommu systems.
    This patch avoids separate /proc/pid/exe code on nommu systems. Instead of
    walking the VMAs to find the first executable file-backed VMA we store a
    reference to the exec'd file in the mm_struct.

    That reference would prevent the filesystem holding the executable file
    from being unmounted even after unmapping the VMAs. So we track the number
    of VM_EXECUTABLE VMAs and drop the new reference when the last one is
    unmapped. This avoids pinning the mounted filesystem.

    [akpm@linux-foundation.org: improve comments]
    [yamamoto@valinux.co.jp: fix dup_mmap]
    Signed-off-by: Matt Helsley
    Cc: Oleg Nesterov
    Cc: David Howells
    Cc:"Eric W. Biederman"
    Cc: Christoph Hellwig
    Cc: Al Viro
    Cc: Hugh Dickins
    Signed-off-by: YAMAMOTO Takashi
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Matt Helsley
     

28 Apr, 2008

1 commit

  • Don't perform kobjsize operations on objects the kernel doesn't manage.

    On Blackfin, drivers can get dma coherent memory by calling a function
    dma_alloc_coherent(). We do this in nommu by configuring a chunk of uncached
    memory at the top of memory.

    Since we don't want the kernel to use the uncached memory, we lie to the
    kernel, and tell it that it's max memory is between 0, and the start of the
    uncached dma coherent section.

    this all works well, until this memory gets exposed into userspace (with a
    frame buffer), when you look at the process's maps, it shows the framebuf:

    root:/proc> cat maps
    [snip]
    03f0ef00-03f34700 rw-p 00000000 1f:00 192 /dev/fb0
    root:/proc>

    This is outside the "normal" range for the kernel. When the kernel tries to
    find the size of this object (when you run ps), it dies in nommu.c in
    kobjsize.

    BUG_ON(page->index >= MAX_ORDER);

    since the page we are referring to is outside what the kernel thinks is it's
    max valid memory.

    root:~> while [ 1 ]; ps > /dev/null; done
    kernel BUG at mm/nommu.c:119!
    Kernel panic - not syncing: BUG!

    We fixed this by adding a check to reject out of range object pointers as it
    already does that for NULL pointers.

    Signed-off-by: Michael Hennerich
    Signed-off-by: Robin Getz
    Acked-by: David Howells
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Michael Hennerich
     

06 Feb, 2008

2 commits

  • This builds on top of the earlier vmalloc_32_user() work introduced by
    b50731732f926d6c49fd0724616a7344c31cd5cf, as we now have places in the nommu
    allmodconfig that hit up against these missing APIs.

    As vmalloc_32_user() is already implemented, this is moved over to
    vmalloc_user() and simply made a wrapper. As all current nommu platforms are
    32-bit addressable, there's no special casing we have to do for ZONE_DMA and
    things of that nature as per GFP_VMALLOC32.

    remap_vmalloc_range() needs to check VM_USERMAP in order to figure out whether
    we permit the remap or not, which means that we also have to rework the
    vmalloc_user() code to grovel for the VMA and set the flag.

    Signed-off-by: Paul Mundt
    Acked-by: David McCullough
    Acked-by: David Howells
    Acked-by: Greg Ungerer
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Paul Mundt
     
  • Make vmalloc functions work the same way as kfree() and friends that
    take a const void * argument.

    [akpm@linux-foundation.org: fix consts, coding-style]
    Signed-off-by: Christoph Lameter
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Christoph Lameter
     

05 Dec, 2007

1 commit

  • If mmap_min_addr is set and a process attempts to mmap (not fixed) with a
    non-null hint address less than mmap_min_addr the mapping will fail the
    security checks. Since this is just a hint address this patch will round
    such a hint address above mmap_min_addr.

    gcj was found to try to be very frugal with vm usage and give hint addresses
    in the 8k-32k range. Without this patch all such programs failed and with
    the patch they happily get a higher address.

    This patch is wrappad in CONFIG_SECURITY since mmap_min_addr doesn't exist
    without it and there would be no security check possible no matter what. So
    we should not bother compiling in this rounding if it is just a waste of
    time.

    Signed-off-by: Eric Paris
    Signed-off-by: James Morris

    Eric Paris
     

29 Oct, 2007

1 commit


20 Oct, 2007

1 commit


17 Oct, 2007

1 commit

  • This patch contains the following cleanups that are now possible:
    - remove the unused security_operations->inode_xattr_getsuffix
    - remove the no longer used security_operations->unregister_security
    - remove some no longer required exit code
    - remove a bunch of no longer used exports

    Signed-off-by: Adrian Bunk
    Acked-by: James Morris
    Cc: Chris Wright
    Cc: Stephen Smalley
    Cc: Serge Hallyn
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Adrian Bunk
     

23 Aug, 2007

1 commit

  • The new exec code inserts an accounted vma into an mm struct which is not
    current->mm. The existing memory check code has a hard coded assumption
    that this does not happen as does the security code.

    As the correct mm is known we pass the mm to the security method and the
    helper function. A new security test is added for the case where we need
    to pass the mm and the existing one is modified to pass current->mm to
    avoid the need to change large amounts of code.

    (Thanks to Tobias for fixing rejects and testing)

    Signed-off-by: Alan Cox
    Cc: WU Fengguang
    Cc: James Morris
    Cc: Tobias Diedrich
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Alan Cox
     

22 Jul, 2007

1 commit

  • Trying to survive an allmodconfig on a nommu platform results in many
    screen lengths of module unhappiness. Many of the mmap related things that
    binfmt_flat hooks in to are never exported despite being global, and there
    are also missing definitions for vmalloc_32_user() and vm_insert_page().

    I've implemented vmalloc_32_user() trying to stick as close to the
    mm/vmalloc.c implementation as possible, though we don't have any need for
    VM_USERMAP, so groveling for the VMA can be skipped. vm_insert_page() has
    been stubbed for now in order to keep the build happy.

    Signed-off-by: Paul Mundt
    Cc: David Howells
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Paul Mundt
     

20 Jul, 2007

2 commits

  • Change ->fault prototype. We now return an int, which contains
    VM_FAULT_xxx code in the low byte, and FAULT_RET_xxx code in the next byte.
    FAULT_RET_ code tells the VM whether a page was found, whether it has been
    locked, and potentially other things. This is not quite the way he wanted
    it yet, but that's changed in the next patch (which requires changes to
    arch code).

    This means we no longer set VM_CAN_INVALIDATE in the vma in order to say
    that a page is locked which requires filemap_nopage to go away (because we
    can no longer remain backward compatible without that flag), but we were
    going to do that anyway.

    struct fault_data is renamed to struct vm_fault as Linus asked. address
    is now a void __user * that we should firmly encourage drivers not to use
    without really good reason.

    The page is now returned via a page pointer in the vm_fault struct.

    Signed-off-by: Nick Piggin
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     
  • Nonlinear mappings are (AFAIKS) simply a virtual memory concept that encodes
    the virtual address -> file offset differently from linear mappings.

    ->populate is a layering violation because the filesystem/pagecache code
    should need to know anything about the virtual memory mapping. The hitch here
    is that the ->nopage handler didn't pass down enough information (ie. pgoff).
    But it is more logical to pass pgoff rather than have the ->nopage function
    calculate it itself anyway (because that's a similar layering violation).

    Having the populate handler install the pte itself is likewise a nasty thing
    to be doing.

    This patch introduces a new fault handler that replaces ->nopage and
    ->populate and (later) ->nopfn. Most of the old mechanism is still in place
    so there is a lot of duplication and nice cleanups that can be removed if
    everyone switches over.

    The rationale for doing this in the first place is that nonlinear mappings are
    subject to the pagefault vs invalidate/truncate race too, and it seemed stupid
    to duplicate the synchronisation logic rather than just consolidate the two.

    After this patch, MAP_NONBLOCK no longer sets up ptes for pages present in
    pagecache. Seems like a fringe functionality anyway.

    NOPAGE_REFAULT is removed. This should be implemented with ->fault, and no
    users have hit mainline yet.

    [akpm@linux-foundation.org: cleanup]
    [randy.dunlap@oracle.com: doc. fixes for readahead]
    [akpm@linux-foundation.org: build fix]
    Signed-off-by: Nick Piggin
    Signed-off-by: Randy Dunlap
    Cc: Mark Fasheh
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     

17 Jul, 2007

1 commit


12 Jul, 2007

1 commit

  • Add a new security check on mmap operations to see if the user is attempting
    to mmap to low area of the address space. The amount of space protected is
    indicated by the new proc tunable /proc/sys/vm/mmap_min_addr and defaults to
    0, preserving existing behavior.

    This patch uses a new SELinux security class "memprotect." Policy already
    contains a number of allow rules like a_t self:process * (unconfined_t being
    one of them) which mean that putting this check in the process class (its
    best current fit) would make it useless as all user processes, which we also
    want to protect against, would be allowed. By taking the memprotect name of
    the new class it will also make it possible for us to move some of the other
    memory protect permissions out of 'process' and into the new class next time
    we bump the policy version number (which I also think is a good future idea)

    Acked-by: Stephen Smalley
    Acked-by: Chris Wright
    Signed-off-by: Eric Paris
    Signed-off-by: James Morris

    Eric Paris
     

09 May, 2007

1 commit

  • This patch moves the die notifier handling to common code. Previous
    various architectures had exactly the same code for it. Note that the new
    code is compiled unconditionally, this should be understood as an appel to
    the other architecture maintainer to implement support for it aswell (aka
    sprinkling a notify_die or two in the proper place)

    arm had a notifiy_die that did something totally different, I renamed it to
    arm_notify_die as part of the patch and made it static to the file it's
    declared and used at. avr32 used to pass slightly less information through
    this interface and I brought it into line with the other architectures.

    [akpm@linux-foundation.org: build fix]
    [akpm@linux-foundation.org: fix vmalloc_sync_all bustage]
    [bryan.wu@analog.com: fix vmalloc_sync_all in nommu]
    Signed-off-by: Christoph Hellwig
    Cc:
    Cc: Russell King
    Signed-off-by: Bryan Wu
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Christoph Hellwig
     

13 Apr, 2007

1 commit


23 Mar, 2007

2 commits

  • Make the SYSV SHM nattch counter work correctly by forcing multiple VMAs to
    be produced to represent MAP_SHARED segments, even if they overlap exactly.

    Using this test program:

    http://people.redhat.com/~dhowells/doshm.c

    Run as:

    doshm sysv

    I can see nattch going from one before the patch:

    # /doshm sysv
    Command: sysv
    shmid: 65536
    memory: 0xc3700000
    c0b00000-c0b04000 rw-p 00000000 00:00 0
    c0bb0000-c0bba788 r-xs 00000000 00:0b 14582157 /lib/ld-uClibc-0.9.28.so
    c3180000-c31dede4 r-xs 00000000 00:0b 14582179 /lib/libuClibc-0.9.28.so
    c3520000-c352278c rw-p 00000000 00:0b 13763417 /doshm
    c3584000-c35865e8 r-xs 00000000 00:0b 13763417 /doshm
    c3588000-c358aa00 rw-p 00008000 00:0b 14582157 /lib/ld-uClibc-0.9.28.so
    c3590000-c359b6c0 rw-p 00000000 00:00 0
    c3620000-c3640000 rwxp 00000000 00:00 0
    c3700000-c37fa000 rw-S 00000000 00:06 1411 /SYSV00000000 (deleted)
    c3700000-c37fa000 rw-S 00000000 00:06 1411 /SYSV00000000 (deleted)
    nattch 1

    To two after the patch:

    # /doshm sysv
    Command: sysv
    shmid: 0
    memory: 0xc3700000
    c0bb0000-c0bba788 r-xs 00000000 00:0b 14582157 /lib/ld-uClibc-0.9.28.so
    c3180000-c31dede4 r-xs 00000000 00:0b 14582179 /lib/libuClibc-0.9.28.so
    c3320000-c3340000 rwxp 00000000 00:00 0
    c3530000-c35325e8 r-xs 00000000 00:0b 13763417 /doshm
    c3534000-c353678c rw-p 00000000 00:0b 13763417 /doshm
    c3538000-c353aa00 rw-p 00008000 00:0b 14582157 /lib/ld-uClibc-0.9.28.so
    c3590000-c359b6c0 rw-p 00000000 00:00 0
    c35a4000-c35a8000 rw-p 00000000 00:00 0
    c3700000-c37fa000 rw-S 00000000 00:06 1369 /SYSV00000000 (deleted)
    c3700000-c37fa000 rw-S 00000000 00:06 1369 /SYSV00000000 (deleted)
    nattch 2

    That's +1 to nattch for each shmat() made.

    Signed-off-by: David Howells
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    David Howells
     
  • Supply a get_unmapped_area() to fix NOMMU SYSV SHM support.

    Signed-off-by: David Howells
    Acked-by: Adam Litke
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    David Howells
     

09 Dec, 2006

1 commit