common: make cpaccess module code writeable

cpaccess has self-modifying code. This does not work when
CONFIG_DEBUG_SET_MODULE_RONX is set and cpaccess is built
as a module, because the text section is marked not writeable.
Call mm function to make the modified instruction writeable.

Change-Id: I317ab55cd6bdceae429ad89629818ab5f7f99599
Signed-off-by: Neil Leeder <nleeder@codeaurora.org>
cpaccess: remove use of set_get_l2_indirect_reg()

cpaccess is the only client of set_get_l2_indirect_reg(), a special-
purpose API for writing an indirect Krait CP15 register and reading
back the new value. For simplicity, this API is being removed and
replaced with bacl-to-back calls to set_l2_indirect_reg() and
get_l2_indirect_reg(), which should perform comparably.

Change-Id: I868ae115265c59e58ffd37dc405a91c6962e0c3d
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>
genalloc: stop crashing the system when destroying a pool

The genalloc code uses the bitmap API from include/linux/bitmap.h and
lib/bitmap.c, which is based on long values.  Both bitmap_set from
lib/bitmap.c and bitmap_set_ll, which is the lockless version from
genalloc.c, use BITMAP_LAST_WORD_MASK to set the first bits in a long in
the bitmap.

That one uses (1 << bits) - 1, 0b111, if you are setting the first three
bits.  This means that the API counts from the least significant bits
(LSB from now on) to the MSB.  The LSB in the first long is bit 0, then.
The same works for the lookup functions.

The genalloc code uses longs for the bitmap, as it should.  In
include/linux/genalloc.h, struct gen_pool_chunk has unsigned long
bits[0] as its last member.  When allocating the struct, genalloc should
reserve enough space for the bitmap.  This should be a proper number of
longs that can fit the amount of bits in the bitmap.

However, genalloc allocates an integer number of bytes that fit the
amount of bits, but may not be an integer amount of longs.  9 bytes, for
example, could be allocated for 70 bits.

This is a problem in itself if the Least Significat Bit in a long is in
the byte with the largest address, which happens in Big Endian machines.
This means genalloc is not allocating the byte in which it will try to
set or check for a bit.

This may end up in memory corruption, where genalloc will try to set the
bits it has not allocated.  In fact, genalloc may not set these bits
because it may find them already set, because they were not zeroed since
they were not allocated.  And that's what causes a BUG when
gen_pool_destroy is called and check for any set bits.

What really happens is that genalloc uses kmalloc_node with __GFP_ZERO
on gen_pool_add_virt.  With SLAB and SLUB, this means the whole slab
will be cleared, not only the requested bytes.  Since struct
gen_pool_chunk has a size that is a multiple of 8, and slab sizes are
multiples of 8, we get lucky and allocate and clear the right amount of
bytes.

Hower, this is not the case with SLOB or with older code that did memset
after allocating instead of using __GFP_ZERO.

So, a simple module as this (running 3.6.0), will cause a crash when
rmmod'ed.

  [root@phantom-lp2 foo]# cat foo.c
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/genalloc.h>

  MODULE_LICENSE("GPL");
  MODULE_VERSION("0.1");

  static struct gen_pool *foo_pool;

  static __init int foo_init(void)
  {
          int ret;
          foo_pool = gen_pool_create(10, -1);
          if (!foo_pool)
                  return -ENOMEM;
          ret = gen_pool_add(foo_pool, 0xa0000000, 32 << 10, -1);
          if (ret) {
                  gen_pool_destroy(foo_pool);
                  return ret;
          }
          return 0;
  }

  static __exit void foo_exit(void)
  {
          gen_pool_destroy(foo_pool);
  }

  module_init(foo_init);
  module_exit(foo_exit);
  [root@phantom-lp2 foo]# zcat /proc/config.gz | grep SLOB
  CONFIG_SLOB=y
  [root@phantom-lp2 foo]# insmod ./foo.ko
  [root@phantom-lp2 foo]# rmmod foo
  ------------[ cut here ]------------
  kernel BUG at lib/genalloc.c:243!
  cpu 0x4: Vector: 700 (Program Check) at [c0000000bb0e7960]
      pc: c0000000003cb50c: .gen_pool_destroy+0xac/0x110
      lr: c0000000003cb4fc: .gen_pool_destroy+0x9c/0x110
      sp: c0000000bb0e7be0
     msr: 8000000000029032
    current = 0xc0000000bb0e0000
    paca    = 0xc000000006d30e00   softe: 0        irq_happened: 0x01
      pid   = 13044, comm = rmmod
  kernel BUG at lib/genalloc.c:243!
  [c0000000bb0e7ca0] d000000004b00020 .foo_exit+0x20/0x38 [foo]
  [c0000000bb0e7d20] c0000000000dff98 .SyS_delete_module+0x1a8/0x290
  [c0000000bb0e7e30] c0000000000097d4 syscall_exit+0x0/0x94
  --- Exception: c00 (System Call) at 000000800753d1a0
  SP (fffd0b0e640) is in userspace

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Benjamin Gaignard <benjamin.gaignard@stericsson.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Git-commit: eedce141cd2dad8d0cefc5468ef41898949a7031
Git-repo: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git
Change-Id: Ic8a8a2d05ee16d59af61d0cc79c88e6e7ab442ae
Signed-off-by: Sunil Khatri <sunilkh@codeaurora.org>
genalloc: Correct nbytes calculation on long boundary

In existing code we calculate nbytes based on the byte
boundary, but genalloc uses bitmap for maintaining the
memory allocation aligned to long. So while calculating
nbytes we end up getting wrong nbytes.
example: lets say nbytes comes to 9 bytes for 70 bits when
bytes aligned,but if long aligned we will have 3 long words
i.e 12 bytes. This difference may lead to choosing the
wrong api for freeing the memory i.e Between kfree() and
vfree().
Fix was inspired by an upstream commit
eedce141cd2dad8d0cefc5468ef41898949a7031, bringing same fix
into the gen_pool_detroy path.

Change-Id: I942caf59e25515c780896b328b912604df9e10bf
Signed-off-by: Hareesh Gundu <hareeshg@codeaurora.org>
Signed-off-by: Sunil Khatri <sunilkh@codeaurora.org>
sysctl: Don't scan for the leaks on headers

These header allocations have life cycle till the device goes
shutdown. So, considering them as leak is false positive. Remove
them by marking kmemleak_not_leak

CRs-Fixed: 466552
Change-Id: Id1571b78365e533ddfe866d45cef8f89b0b62bc7
Signed-off-by: Chintan Pandya <cpandya@codeaurora.org>
ext4: fix the free blocks calculation for ext3 file systems w/ uninit_bg

Ext3 filesystems that are converted to use as many ext4 file system
features as possible will enable uninit_bg to speed up e2fsck times.
These file systems will have a native ext3 layout of inode tables and
block allocation bitmaps (as opposed to ext4's flex_bg layout).
Unfortunately, in these cases, when first allocating a block in an
uninitialized block group, ext4 would incorrectly calculate the number
of free blocks in that block group, and then errorneously report that
the file system was corrupt:

EXT4-fs error (device vdd): ext4_mb_generate_buddy:741: group 30, 32254 clusters in bitmap, 32258 in gd

This problem can be reproduced via:

    mke2fs -q -t ext4 -O ^flex_bg /dev/vdd 5g
    mount -t ext4 /dev/vdd /mnt
    fallocate -l 4600m /mnt/test

The problem was caused by a bone headed mistake in the check to see if a
particular metadata block was part of the block group.

Many thanks to Kees Cook for finding and bisecting the buggy commit
which introduced this bug (commit fd034a84e1, present since v3.2).

Change-Id: I122951d5528178c8af75e3f7425b5eae9ccdb036
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Reported-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Tested-by: Kees Cook <keescook@chromium.org>
Cc: stable@kernel.org
CRs-Fixed: 576063
Git-commit: b0dd6b70f0fda17ae9762fbb72d98e40a4f66556
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>
ext4: make sure the journal sb is written in ext4_clear_journal_err()

After we transfer set the EXT4_ERROR_FS bit in the file system
superblock, it's not enough to call jbd2_journal_clear_err() to clear
the error indication from journal superblock --- we need to call
jbd2_journal_update_sb_errno() as well.  Otherwise, when the root file
system is mounted read-only, the journal is replayed, and the error
indicator is transferred to the superblock --- but the s_errno field
in the jbd2 superblock is left set (since although we cleared it in
memory, we never flushed it out to disk).

This can end up confusing e2fsck.  We should make e2fsck more robust
in this case, but the kernel shouldn't be leaving things in this
confused state, either.

Change-Id: I7a7cd58880209fbd54f4ded5f2b62de492cae9e0
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
Git-commit: d796c52ef0b71a988364f6109aeb63d79c5b116b
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Osvaldo Banuelos <osvaldob@codeaurora.org>
ext4: fix memory leak in xattr

If we take the 2nd retry path in ext4_expand_extra_isize_ea, we
potentionally return from the function without having freed these
allocations.  If we don't do the return, we over-write the previous
allocation pointers, so we leak either way.

Spotted with Coverity.

[ Fixed by tytso to set is and bs to NULL after freeing these
  pointers, in case in the retry loop we later end up triggering an
  error causing a jump to cleanup, at which point we could have a double
  free bug. -- Ted ]

Change-Id: I49b8ca41a6c6d44b563eb23306870258a3affd3b
Signed-off-by: Dave Jones <davej@fedoraproject.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Cc: stable@vger.kernel.org
Git-commit: 6e4ea8e33b2057b85d75175dd89b93f5e26de3bc
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Osvaldo Banuelos <osvaldob@codeaurora.org>
jbd2: Fix use after free after error in jbd2_journal_dirty_metadata()

When jbd2_journal_dirty_metadata() returns error,
__ext4_handle_dirty_metadata() stops the handle. However callers of this
function do not count with that fact and still happily used now freed
handle. This use after free can result in various issues but very likely
we oops soon.

The motivation of adding __ext4_journal_stop() into
__ext4_handle_dirty_metadata() in commit 9ea7a0df seems to be only to
improve error reporting. So replace __ext4_journal_stop() with
ext4_journal_abort_handle() which was there before that commit and add
WARN_ON_ONCE() to dump stack to provide useful information.

Change-Id: Ibfd59e399f4a11abc378a237e10b3741bef2a15e
Reported-by: Sage Weil <sage@inktank.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org	# 3.2+
Git-commit: 91aa11fae1cf8c2fd67be0609692ea9741cdcc43
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Osvaldo Banuelos <osvaldob@codeaurora.org>
fs: fuse: Add replacment for CMA pages into the LRU cache

CMA pages are currently replaced in the FUSE file system since
FUSE may hold on to CMA pages for a long time, preventing migration.
The replacement page is added to the file cache but not the LRU
cache. This may prevent the page from being properly aged and dropped,
creating poor performance under tight memory condition. Fix this by
adding the new page to the LRU cache after creation.

Change-Id: Ib349abf1024d48386b835335f3fbacae040b6241
CRs-Fixed: 586855
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
fat: limit the number of error prints

Use fat_fs_error_ratelimit instead of fat_fs_error so as to
avoid large number of prints.

Change-Id: I2e21e6bd0c8e7e79d3ced9c213668c405fd6260d
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
fat: limit the number of error prints

Use fat_fs_error_ratelimit instead of fat_fs_error so as to
avoid large number of prints.

CRs-Fixed: 619824
Change-Id: I458df6c2c7a53c0902f2b388b5992007b719cb86
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
ARM: Flush the caches for non panicking CPUs in case of a kernel panic

In case of a kernel panic, only the panicking CPU does an entire
cache flush. This means that certain dirty cache lines in the L1
caches of the other CPUs may never get flushed. This gives us
improper RAM dumps. Add cache flushing for all the online CPUs.
The outer domain is not flushed since it is already being done by
the panicking CPU.

Change-Id: Ibf844ecf6b4dbc3c623789f72a26936aeb4a7306
Signed-off-by: Syed Rameez Mustafa <rameezmustafa@codeaurora.org>
workqueue: Added null check and warning

If work item is already in queue get_work_cwq() will return null.
so null check is added to avoid crash in delayed_work_timer_on()

CRs-Fixed: 586162

Change-Id: I5c885142fd72781cea90d6c9b3456ecc7f0778b6
Signed-off-by: Srinivasarao P <spathi@codeaurora.org>
ARM: cacheflush: don't round address range up to nearest page

The flush_cache_user_range macro takes a pair of addresses describing
the start and end of the virtual address range to flush. Due to an
accidental oversight when flush_cache_range_user was introduced, the
address range was rounded up so that the start and end addresses were
page-aligned.

For historical reference, the interesting commits in history.git are:

10eacf1775e1 ("[ARM] Clean up ARM cache handling interfaces (part 1)")
71432e79b76b ("[ARM] Add flush_cache_user_page() for sys_cacheflush()")

This patch removes the alignment code, reducing the amount of flushing
required for ranges that are not an exact multiple of PAGE_SIZE.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Jonathan Austin <jonathan.austin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
random: entropy tweaks are all the rage nowadays

use nonblocking for all.  Read this web page:
http://lwn.net/Articles/489734/

Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
random: prevent add_input from doing anything

Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
timer: optimize apply_slack()

__fls(mask) is equivalent to find_last_bit(&mask, BITS_PER_LONG), but cheaper.
find_last_bit was showing up high on the list when I was profiling for stalls
on icache misses on a system with very small cache size (MIPS).

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
lib/int_sqrt.c: optimize square root algorithm

Optimize the current version of the shift-and-subtract (hardware)
algorithm, described by John von Newmann[1] and Guy L Steele.

Iterating 1,000,000 times, perf shows for the current version:

 Performance counter stats for './sqrt-curr' (10 runs):

         27.170996 task-clock                #    0.979 CPUs utilized            ( +-  3.19% )
                 3 context-switches          #    0.103 K/sec                    ( +-  4.76% )
                 0 cpu-migrations            #    0.004 K/sec                    ( +-100.00% )
               104 page-faults               #    0.004 M/sec                    ( +-  0.16% )
        64,921,199 cycles                    #    2.389 GHz                      ( +-  0.03% )
        28,967,789 stalled-cycles-frontend   #   44.62% frontend cycles idle     ( +-  0.18% )
   <not supported> stalled-cycles-backend
       104,502,623 instructions              #    1.61  insns per cycle
                                             #    0.28  stalled cycles per insn  ( +-  0.00% )
        34,088,368 branches                  # 1254.587 M/sec                    ( +-  0.00% )
             4,901 branch-misses             #    0.01% of all branches          ( +-  1.32% )

       0.027763015 seconds time elapsed                                          ( +-  3.22% )

And for the new version:

Performance counter stats for './sqrt-new' (10 runs):

          0.496869 task-clock                #    0.519 CPUs utilized            ( +-  2.38% )
                 0 context-switches          #    0.000 K/sec
                 0 cpu-migrations            #    0.403 K/sec                    ( +-100.00% )
               104 page-faults               #    0.209 M/sec                    ( +-  0.15% )
           590,760 cycles                    #    1.189 GHz                      ( +-  2.35% )
           395,053 stalled-cycles-frontend   #   66.87% frontend cycles idle     ( +-  3.67% )
   <not supported> stalled-cycles-backend
           398,963 instructions              #    0.68  insns per cycle
                                             #    0.99  stalled cycles per insn  ( +-  0.39% )
            70,228 branches                  #  141.341 M/sec                    ( +-  0.36% )
             3,364 branch-misses             #    4.79% of all branches          ( +-  5.45% )

       0.000957440 seconds time elapsed                                          ( +-  2.42% )

Furthermore, this saves space in instruction text:

   text    data     bss     dec     hex filename
    111       0       0     111      6f lib/int_sqrt-baseline.o
     89       0       0      89      59 lib/int_sqrt.o

[1] http://en.wikipedia.org/wiki/First_Draft_of_a_Report_on_the_EDVAC

Change-Id: I3b37bcf6924aca20f9f77b8bbf6857f8d517d354
Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Reviewed-by: Jonathan Gonzalez <jgonzlez@linets.cl>
Tested-by: Jonathan Gonzalez <jgonzlez@linets.cl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
nohz: Reduce overhead under high-freq idling patterns

One testbox of mine (Intel Nehalem, 16-way) uses MWAIT for its idle routine,
which apparently can break out of its idle loop rather frequently, with
high frequency.

In that case NO_HZ_FULL=y kernels show high ksoftirqd overhead and constant
context switching, because tick_nohz_stop_sched_tick() will, if
delta_jiffies == 0, mis-identify this as a timer event - activating the
TIMER_SOFTIRQ, which wakes up ksoftirqd.

Fix this by treating delta_jiffies == 0 the same way we treat other short
wakeups, delta_jiffies == 1.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>

Change-Id: I2a9956cb493d50c2d599d527fc3917eef41d01a4
Signed-off-by: Ingo Molnar <mingo@kernel.org>