The only time when granted pages need to be treated specially is when
using Xen's PTE modification for grant mappings owned by another domain
(that is, only gntdev on PV guests).  Otherwise, the area does not
require VM_DONTCOPY and VM_PFNMAP, since it can be accessed just like
any other page of RAM.

Since the vm_operations_struct close operations decrement reference
counts, a corresponding open function that increments them is required
now that it is possible to have multiple references to a single area.

We are careful in the gntdev to check if we can remove those flags. The
reason that we need to be careful in gntdev on PV guests is because we are
not changing the PFN/MFN mapping on PV; instead, we change the application's
page tables to point to the other domain's memory. This means that the vma
cannot be copied without using another grant mapping hypercall; it also
requires special handling on unmap, which is the reason for gntdev's
dependency on the MMU notifier.

For gntalloc, this is not a concern - the pages are owned by the domain
using the gntalloc device, and can be mapped and unmapped in the same manner
as any other page of memory.
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
[v2: Added in git commit "We are.." from email correspondence]

addr is actually a virtual address so use an unsigned long. Fixes:

  CC      drivers/xen/gntdev.o
drivers/xen/gntdev.c: In function 'map_grant_pages':
drivers/xen/gntdev.c:268: warning: cast from pointer to integer of different size

Reduce the scope of the variable at the same time.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The caller will not undo a mapping which failed and therefore the
override will not be removed.

This is especially bad in the case of GNTMAP_contains_pte mapping type
mappings where m2p_add_override will destroy the kernel mapping of the
page.

This was observed via a failure of map_grant_pages in gntdev_mmap (due
to userspace using a bad grant reference), which left the page in
question unmapped (because it was a GNTMAP_contains_pte mapping) which
led to a crash later on.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The handle with numeric value 0 is a valid map handle, so it cannot
be used to indicate that a page has not been mapped. Use -1 instead.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

When CONFIG_XEN is enabled the gntdev and gntalloc driver will be
compiled as a module by default.

[v2: Added the fix for the gntalloc driver as well]
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

If an already-mapped area of the device was mapped into userspace a
second time, a hypercall was incorrectly made to remap the memory
again. Avoid the hypercall on later mmap calls, and fail the mmap call
if a writable mapping is attempted on a read-only range.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

In paravirtualized domains, mn_invl_page or mn_invl_range_start can
unmap a segment of a mapped region without unmapping all pages. When
the region is later released, the pages will be unmapped twice, leading
to an incorrect -EINVAL return.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The is_mapped flag used to be set at the completion of the map operation,
but was not checked in all error paths. Use map->vma instead, which will
now be cleared if the initial grant mapping fails.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

In paravirtualized guests, the struct page* for mappings is only a
placeholder, and cannot be used to access the granted memory. Use the
userspace mapping that we have set up in order to implement
UNMAP_NOTIFY_CLEAR_BYTE.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The error path did not decrement the reference count of the grant structure.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

This ioctl allows the users of a shared page to be notified when
the other end exits abnormally.

[v2: updated description in structs]
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

This allows a userspace application to allocate a shared page for
implementing inter-domain communication or device drivers. These
shared pages can be mapped using the gntdev device or by the kernel
in another domain.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

HVM does not allow direct PTE modification, so instead we request
that Xen change its internal p2m mappings on the allocated pages and
map the memory into userspace normally.

Note:
The HVM path for map and unmap is slightly different: HVM keeps the pages
mapped until the area is deleted, while the PV case (use_ptemod being true)
must unmap them when userspace unmaps the range. In the normal use case,
this makes no difference to users since unmap time is deletion time.

[v2: Expanded commit descr.]
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

This allows userspace to perform mmap() on the gntdev device and then
immediately close the filehandle or remove the mapping using the
remove ioctl, with the mapped area remaining valid until unmapped.
This also fixes an infinite loop when a gntdev device is closed
without first unmapping all areas.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

This should be faster if many mappings exist, and also removes
the only user of map->vma not related to PTE modification.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Because there is no limitation on how many times a user can open a
given device file, an per-file-description limit on the number of
pages granted offers little to no benefit. Change to a global limit
and remove the ioctl() as the parameter can now be changed via sysfs.

Xen tools changeset 22768:f8d801e5573e is needed to eliminate the
error this change produces in xc_gnttab_set_max_grants.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

* master.kernel.org:/home/rmk/linux-2.6-arm:
  ALSA: AACI: allow writes to MAINCR to take effect
  ARM: Update mach-types
  ARM: 6652/1: ep93xx: correct the end address of the AC97 memory resource
  ARM: mxs/imx28: remove now unused clock lookup "fec.0"
  ARM: mxs: fix clock base address missing
  ARM: mxs: acknowledge gpio irq
  ARM: mach-imx/mach-mx25_3ds: Fix section type
  ARM: imx: Add VPR200 and MX51_3DS entries to uncompress.h
  ARM i.MX23: use correct register for setting the rate
  ARM i.MX23/28: remove secondary field from struct clk. It's unused
  ARM i.MX28: use correct register for setting the rate
  ARM i.MX28: fix bit operation

* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (33 commits)
  Btrfs: Fix page count calculation
  btrfs: Drop __exit attribute on btrfs_exit_compress
  btrfs: cleanup error handling in btrfs_unlink_inode()
  Btrfs: exclude super blocks when we read in block groups
  Btrfs: make sure search_bitmap finds something in remove_from_bitmap
  btrfs: fix return value check of btrfs_start_transaction()
  btrfs: checking NULL or not in some functions
  Btrfs: avoid uninit variable warnings in ordered-data.c
  Btrfs: catch errors from btrfs_sync_log
  Btrfs: make shrink_delalloc a little friendlier
  Btrfs: handle no memory properly in prepare_pages
  Btrfs: do error checking in btrfs_del_csums
  Btrfs: use the global block reserve if we cannot reserve space
  Btrfs: do not release more reserved bytes to the global_block_rsv than we need
  Btrfs: fix check_path_shared so it returns the right value
  btrfs: check return value of btrfs_start_ioctl_transaction() properly
  btrfs: fix return value check of btrfs_join_transaction()
  fs/btrfs/inode.c: Add missing IS_ERR test
  btrfs: fix missing break in switch phrase
  btrfs: fix several uncheck memory allocations
  ...

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc: Fix hcall tracepoint recursion
  powerpc/numa: Fix bug in unmap_cpu_from_node
  powerpc/numa: Disable VPHN on dedicated processor partitions
  powerpc/numa: Add length when creating OF properties via VPHN
  powerpc/numa: Check for all VPHN changes
  powerpc/numa: Only use active VPHN count fields
  powerpc/pseries: Remove unnecessary variable initializations in numa.c
  powerpc/pseries: Fix brace placement in numa.c
  powerpc/pseries: Fix typo in VPHN comments
  powerpc: Fix some 6xx/7xxx CPU setup functions
  powerpc: Pass the right cpu_spec to ->setup_cpu() on 64-bit
  powerpc/book3e: Protect complex macro args in mmu-book3e.h
  powerpc: Fix pfn_valid() when memory starts at a non-zero address

Merge branch 'omap-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6

* 'omap-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6:
  arm: omap4: panda: remove usb_nop_xceiv_register(v1)
  OMAP1: Fix non-working LCD on OMAP310
  OMAP3: Devkit8000: Change lcd power pin
  omap1: remove duplicated #include
  arm: mach-omap2: mux: free allocated memory on error exit
  arm: mach-omap2: board-rm680: fix rm680_vemmc regulator constraints
  OMAP: PM: SmartReflex: Fix possible null pointer read access
  OMAP: PM: SmartReflex: Fix possible memory leak
  arm: mach-omap2: voltage: debugfs: fix memory leak
  OMAP3: PM: fix save secure RAM to restore MPU power state
  OMAP: PM: SmartReflex: Add missing IS_ERR test

Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, nx: Mark the ACPI resume trampoline code as +x

In prepare_kernel_cred() since 2.6.29, put_cred(new) is called without
assigning new->usage when security_prepare_creds() returned an error.  As a
result, memory for new and refcount for new->{user,group_info,tgcred} are
leaked because put_cred(new) won't call __put_cred() unless old->usage == 1.

Fix these leaks by assigning new->usage (and new->subscribers which was added
in 2.6.32) before calling security_prepare_creds().
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In cred_alloc_blank() since 2.6.32, abort_creds(new) is called with
new->security == NULL and new->magic == 0 when security_cred_alloc_blank()
returns an error.  As a result, BUG() will be triggered if SELinux is enabled
or CONFIG_DEBUG_CREDENTIALS=y.

If CONFIG_DEBUG_CREDENTIALS=y, BUG() is called from __invalid_creds() because
cred->magic == 0.  Failing that, BUG() is called from selinux_cred_free()
because selinux_cred_free() is not expecting cred->security == NULL.  This does
not affect smack_cred_free(), tomoyo_cred_free() or apparmor_cred_free().

Fix these bugs by

(1) Set new->magic before calling security_cred_alloc_blank().

(2) Handle null cred->security in creds_are_invalid() and selinux_cred_free().
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6:
  cifs: remove checks for ses->status == CifsExiting
  cifs: add check for kmalloc in parse_dacl
  cifs: don't send an echo request unless NegProt has been done
  cifs: enable signing flag in SMB header when server has it on
  cifs: Possible slab memory corruption while updating extended stats (repost)
  CIFS: Fix variable types in cifs_iovec_read/write (try #2)
  cifs: fix length vs. total_read confusion in cifs_demultiplex_thread

take offset of start position into account when calculating page count.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

ses->status is never set to CifsExiting, so these checks are
always false.
Tested-by: JG <jg@cms.ac>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

The AACI TRM requires the MAINCR enable bit to be held zero for two
bitclk cycles plus three apb_pclk cycles.  Use a delay of 1us to
ensure this.

Ensure that writes to MAINCR to change the addressed codec only happen
when required, and that they take effect in a similar manner to the
above, otherwise we seem to occasionally have stuck slot busy bits.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

We reserve lowmem for the things that need it, like the ACPI
wakeup code, way early to guarantee availability.  This happens
before we set up the proper pagetables, so set_memory_x() has no
effect.

Until we have a better solution, use an initcall to mark the
wakeup code executable.
Originally-by: Matthieu Castet <castet.matthieu@free.fr>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Matthias Hopf <mhopf@suse.de>
Cc: rjw@sisk.pl
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <4D4F8019.2090104@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Spinlocks on shared processor partitions use H_YIELD to notify the
hypervisor we are waiting on another virtual CPU. Unfortunately this means
the hcall tracepoints can recurse.

The patch below adds a percpu depth and checks it on both the entry and
exit hcall tracepoints.
Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: stable@kernel.org

When converting to the new cpumask code I screwed up:

-       if (cpu_isset(cpu, numa_cpumask_lookup_table[node])) {
-               cpu_clear(cpu, numa_cpumask_lookup_table[node]);
+       if (cpumask_test_cpu(cpu, node_to_cpumask_map[node])) {
+               cpumask_set_cpu(cpu, node_to_cpumask_map[node]);

This was introduced in commit 25863de0 (powerpc/cpumask: Convert NUMA code
to new cpumask API)

Fix it.
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: <stable@kernel.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

There is no need to start up the timer and monitor topology changes on a
dedicated processor partition, so disable it.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

The rest of the NUMA code expects an OF associativity property with
the first cell containing the length. Without this fix all topology changes
cause us to misparse the property and put the cpu into node 0.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

The hypervisor uses unsigned 1 byte counters to signal topology changes to
the OS. Since they can wrap we need to check for any difference, not just if
the hypervisor count is greater than the previous count.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

VPHN supports up to 8 distance fields but the number of entries in
ibm,associativity-reference-points signifies how many are in use.
Don't look at all the VPHN counts, only distance_ref_points_depth
worth.

Since we already cap our distance metrics at MAX_DISTANCE_REF_POINTS,
use that to size the VPHN arrays and add a BUILD_BUG_ON to avoid it growing
larger than the VPHN maximum of 8.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>