We've had some troubles in the past with weird instructions. This
patch adds a self-test framework which can be used to verify that
a certain set of opcodes are decoded correctly. Of course, the
opcodes which are not tested can still give the wrong results.

In short, this is just a safeguard to catch unintentional changes
in the opcode decoder. It does not mean that errors can't still
occur!

[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

Unify and demacro pte_hidden.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

Only _PAGE_HIDDEN when CONFIG_KMEMCHECK is defined, otherwise set it
to 0.  Allows later cleanups.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

The Kconfig options of kmemcheck are hidden under arch/x86 which makes porting
to other architectures harder. To fix that, move the Kconfig bits to
lib/Kconfig.kmemcheck and introduce a CONFIG_HAVE_ARCH_KMEMCHECK config option
that architectures can define.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>

[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

let it rip!
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegardno@ifi.uio.no>

This adds support for tracking the initializedness of memory that
was allocated with the page allocator. Highmem requests are not
tracked.

Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>

[build fix for !CONFIG_KMEMCHECK]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

This is needed for page allocator support to prevent false positives
when accessing pages which are dma-mapped.

[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

As these are allocated using the page allocator, we need to pass
__GFP_NOTRACK before we add page allocator support to kmemcheck.
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

The xor tests are run on uninitialized data, because it is doesn't
really matter what the underlying data is. Annotate this false-
positive warning.
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

We now have SLAB support for kmemcheck! This means that it doesn't matter
whether one chooses SLAB or SLUB, or indeed whether Linus chooses to chuck
SLAB or SLUB.. ;-)

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>

[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

Parts of this patch were contributed by Pekka Enberg but merged for
atomicity.

Cc: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Vegard Nossum <vegardno@ifi.uio.no>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegardno@ifi.uio.no>

This patch hooks into the DMA API to prevent the reporting of the
false positives that would otherwise be reported when memory is
accessed that is also used directly by devices.

[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

With kmemcheck enabled, the slab allocator needs to do this:

1. Tell kmemcheck to allocate the shadow memory which stores the status of
   each byte in the allocation proper, e.g. whether it is initialized or
   uninitialized.
2. Tell kmemcheck which parts of memory that should be marked uninitialized.
   There are actually a few more states, such as "not yet allocated" and
   "recently freed".

If a slab cache is set up using the SLAB_NOTRACK flag, it will never return
memory that can take page faults because of kmemcheck.

If a slab cache is NOT set up using the SLAB_NOTRACK flag, callers can still
request memory with the __GFP_NOTRACK flag. This does not prevent the page
faults from occuring, however, but marks the object in question as being
initialized so that no warnings will ever be produced for this object.

In addition to (and in contrast to) __GFP_NOTRACK, the
__GFP_NOTRACK_FALSE_POSITIVE flag indicates that the allocation should
not be tracked _because_ it would produce a false positive. Their values
are identical, but need not be so in the future (for example, we could now
enable/disable false positives with a config option).

Parts of this patch were contributed by Pekka Enberg but merged for
atomicity.
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

The hooks that we modify are:
- Page fault handler (to handle kmemcheck faults)
- Debug exception handler (to hide pages after single-stepping
  the instruction that caused the page fault)

Also redefine memset() to use the optimized version if kmemcheck is
enabled.

(Thanks to Pekka Enberg for minimizing the impact on the page fault
handler.)

As kmemcheck doesn't handle MMX/SSE instructions (yet), we also disable
the optimized xor code, and rely instead on the generic C implementation
in order to avoid false-positive warnings.
Signed-off-by: Vegard Nossum <vegardno@ifi.uio.no>

[whitespace fixlet]
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegardno@ifi.uio.no>

Lets use kmemcheck_pte_lookup() in kmemcheck_fault() instead of
open-coding it there.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

This patch moves the CONFIG_X86_64 ifdef out of kmemcheck_opcode_decode() by
introducing a version of the function that always returns false for
CONFIG_X86_32.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

Multiple ifdef'd definitions of the same global variable is ugly and
error-prone. Fix that up.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

The "Bugs, beware!" printout during is cute but confuses users that something
bad happened so change the text to the more boring "Initialized" message.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

This patch reorders code in error.c so that we can get rid of the forward
declarations.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

kmemcheck/shadow.c needs to include <linux/module.h> to prevent
the following warnings:

linux-next-20080724/arch/x86/mm/kmemcheck/shadow.c:64: warning : data definition has no type or storage class
linux-next-20080724/arch/x86/mm/kmemcheck/shadow.c:64: warning : type defaults to 'int' in declaration of 'EXPORT_SYMBOL_GPL'
linux-next-20080724/arch/x86/mm/kmemcheck/shadow.c:64: warning : parameter names (without types) in function declaration
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: vegardno@ifi.uio.no
Cc: penberg@cs.helsinki.fi
Cc: akpm <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

General description: kmemcheck is a patch to the linux kernel that
detects use of uninitialized memory. It does this by trapping every
read and write to memory that was allocated dynamically (e.g. using
kmalloc()). If a memory address is read that has not previously been
written to, a message is printed to the kernel log.

Thanks to Andi Kleen for the set_memory_4k() solution.

Andrew Morton suggested documenting the shadow member of struct page.
Signed-off-by: Vegard Nossum <vegardno@ifi.uio.no>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>

[export kmemcheck_mark_initialized]
[build fix for setup_max_cpus]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegardno@ifi.uio.no>

Thanks to Sitsofe Wheeler, Randy Dunlap, and Jonathan Corbet for providing
input and feedback on this!
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

Acked-by: Vegard Nossum <vegardno@ifi.uio.no>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Rationale: kmemcheck needs to be able to schedule a tasklet without
touching any dynamically allocated memory _at_ _all_ (since that would
lead to a recursive page fault). This tasklet is used for writing the
error reports to the kernel log.

The new scheduling function avoids touching any other tasklets by
inserting the new tasklist as the head of the "tasklet_hi" list instead
of on the tail.

Also don't wake up the softirq thread lest the scheduler access some
tracked memory and we go down with a recursive page fault.

In this case, we'd better just wait for the maximum time of 1/HZ for the
message to appear.
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

Move the SLAB struct kmem_cache definition to <linux/slab_def.h> like
with SLUB so kmemcheck can access ->ctor and ->flags.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>

[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

This is needed if the header is to be free-standing.
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

This will help kmemcheck (and possibly other debugging tools) since we
can now simply pass regs->bp to the stack tracer instead of specifying
the number of stack frames to skip, which is unreliable if gcc decides
to inline functions, etc.

Note that this makes the API incomplete for other architectures, but I
expect that those can be updated lazily, e.g. when they need it.

Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

Fix kernel-doc warnings in recently changed block/ source code.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (87 commits)
  nilfs2: get rid of bd_mount_sem use from nilfs
  nilfs2: correct exclusion control in nilfs_remount function
  nilfs2: simplify remaining sget() use
  nilfs2: get rid of sget use for checking if current mount is present
  nilfs2: get rid of sget use for acquiring nilfs object
  nilfs2: remove meaningless EBUSY case from nilfs_get_sb function
  remove the call to ->write_super in __sync_filesystem
  nilfs2: call nilfs2_write_super from nilfs2_sync_fs
  jffs2: call jffs2_write_super from jffs2_sync_fs
  ufs: add ->sync_fs
  sysv: add ->sync_fs
  hfsplus: add ->sync_fs
  hfs: add ->sync_fs
  fat: add ->sync_fs
  ext2: add ->sync_fs
  exofs: add ->sync_fs
  bfs: add ->sync_fs
  affs: add ->sync_fs
  sanitize ->fsync() for affs
  repair bfs_write_inode(), switch bfs to simple_fsync()
  ...

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu:
  m68knommu: remove unecessary include of thread_info.h in entry.S
  m68knommu: enumerate INIT_THREAD fields properly
  headers_check fix: m68k, swab.h
  arch/m68knommu: Convert #ifdef DEBUG printk(KERN_DEBUG to pr_debug(
  m68knommu: remove obsolete reset code
  m68knommu: move CPU reset code for the 5272 ColdFire into its platform code
  m68knommu: move CPU reset code for the 528x ColdFire into its platform code
  m68knommu: move CPU reset code for the 527x ColdFire into its platform code
  m68knommu: move CPU reset code for the 523x ColdFire into its platform code
  m68knommu: move CPU reset code for the 520x ColdFire into its platform code
  m68knommu: add CPU reset code for the 532x ColdFire
  m68knommu: add CPU reset code for the 5249 ColdFire
  m68knommu: add CPU reset code for the 5206e ColdFire
  m68knommu: add CPU reset code for the 5206 ColdFire
  m68knommu: add CPU reset code for the 5407 ColdFire
  m68knommu: add CPU reset code for the 5307 ColdFire
  m68knommu: merge system reset for code ColdFire 523x family
  m68knommu: fix system reset for ColdFire 527x family

zalloc_cpumask_var already cleared it.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

So we make sure MAXSMP gets a cleared cpumask
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 925d519a ("perf_counter:
unify and fix delayed counter wakeup") added global definitions.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Paul Mackerras <paulus@samba.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This will remove every bd_mount_sem use in nilfs.

The intended exclusion control was replaced by the previous patch
("nilfs2: correct exclusion control in nilfs_remount function") for
nilfs_remount(), and this patch will replace remains with a new mutex
that this inserts in nilfs object.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

nilfs_remount() changes mount state of a superblock instance.  Even
though nilfs accesses other superblock instances during mount or
remount, the mount state was not properly protected in
nilfs_remount().

Moreover, nilfs_remount() has a lock order reversal problem;
nilfs_get_sb() holds:

  1. bdev->bd_mount_sem
  2. sb->s_umount  (sget acquires)

and nilfs_remount() holds:

  1. sb->s_umount  (locked by the caller in vfs)
  2. bdev->bd_mount_sem

To avoid these problems, this patch divides a semaphore protecting
super block instances from nilfs->ns_sem, and applies it to the mount
state protection in nilfs_remount().

With this change, bd_mount_sem use is removed from nilfs_remount() and
the lock order reversal will be resolved.  And the new rw-semaphore,
nilfs->ns_super_sem will properly protect the mount state except the
modification from nilfs_error function.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

This simplifies the test function passed on the remaining sget()
callsite in nilfs.

Instead of checking mount type (i.e. ro-mount/rw-mount/snapshot mount)
in the test function passed to sget(), this patch first looks up the
nilfs_sb_info struct which the given mount type matches, and then
acquires the super block instance holding the nilfs_sb_info.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

This stops using sget() for checking if an r/w-mount or an r/o-mount
exists on the device.  This elimination uses a back pointer to the
current mount added to nilfs object.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

This will change the way to obtain nilfs object in nilfs_get_sb()
function.

Previously, a preliminary sget() call was performed, and the nilfs
object was acquired from a super block instance found by the sget()
call.

This patch, instead, instroduces a new dedicated function
find_or_create_nilfs(); as the name implies, the function finds an
existent nilfs object from a global list or creates a new one if no
object is found on the device.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

The following EBUSY case in nilfs_get_sb() is meaningless.  Indeed,
this error code is never returned to the caller.

    if (!s->s_root) {
          ...
    } else if (!(s->s_flags & MS_RDONLY)) {
        err = -EBUSY;
    }

This simply removes the else case.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Now that all filesystems provide ->sync_fs methods we can change
__sync_filesystem to only call ->sync_fs.

This gives us a clear separation between periodic writeouts which
are driven by ->write_super and data integrity syncs that go
through ->sync_fs. (modulo file_fsync which is also going away)
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>