Add some more comments and reformat existing ones to kernel doc style.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: NDarren Hart <dvhart@linux.intel.com>
Link: http://lkml.kernel.org/r/1464770609-30168-1-git-send-email-bigeasy@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

When we get a hung task it can often be valuable to see _all_ the held
locks on the system (in case we are being blocked on trying to acquire
one), e.g. with this patch we can immediately see where the problem is
below:

    INFO: task trinity-c3:14933 blocked for more than 120 seconds.
	  Not tainted 4.8.0-rc1+ #135
    "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
    trinity-c3      D ffff88010c16fc88     0 14933      1 0x00080004
     ffff88010c16fc88 000000003b9aca00 0000000000000000 0000000000000296
     00000000776cdf88 ffff88011a520ae0 ffff88011a520b08 ffff88011a520198
     ffffffff867d7f00 ffff88011942c080 ffff880116841580 ffff88010c168000
    Call Trace:
     [<ffffffff845e9d37>] schedule+0x77/0x230
     [<ffffffff833cb8b9>] __lock_sock+0x129/0x250
     [<ffffffff833cb790>] ? __sk_destruct+0x450/0x450
     [<ffffffff81408ac0>] ? wake_bit_function+0x2e0/0x2e0
     [<ffffffff833d832b>] lock_sock_nested+0xeb/0x120
     [<ffffffff83bad815>] irda_setsockopt+0x65/0xb40
     [<ffffffff833c6c09>] SyS_setsockopt+0x139/0x230
     [<ffffffff833c6ad0>] ? SyS_recv+0x20/0x20
     [<ffffffff81004660>] ? trace_event_raw_event_sys_enter+0xb90/0xb90
     [<ffffffff823c7023>] ? __this_cpu_preempt_check+0x13/0x20
     [<ffffffff8162ee60>] ? __context_tracking_exit.part.3+0x30/0x1b0
     [<ffffffff833c6ad0>] ? SyS_recv+0x20/0x20
     [<ffffffff81007bd3>] do_syscall_64+0x1b3/0x4b0
     [<ffffffff845f84aa>] entry_SYSCALL64_slow_path+0x25/0x25

    Showing all locks held in the system:
    2 locks held by khungtaskd/563:
     #0:  (rcu_read_lock){......}, at: [<ffffffff81534ce6>] watchdog+0x106/0x910
     #1:  (tasklist_lock){......}, at: [<ffffffff8141b3c4>] debug_show_all_locks+0x74/0x360
    1 lock held by trinity-c0/19280:
     #0:  (sk_lock-AF_IRDA){......}, at: [<ffffffff83bab7c6>] irda_accept+0x176/0x10f0
    1 lock held by trinity-c0/12865:
     #0:  (sk_lock-AF_IRDA){......}, at: [<ffffffff83bab7c6>] irda_accept+0x176/0x10f0
Signed-off-by: NVegard Nossum <vegard.nossum@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mandeep Singh Baines <msb@chromium.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1471538460-7505-1-git-send-email-vegard.nossum@oracle.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

When wanting to wakeup readers, __rwsem_mark_wakeup() currently
iterates the wait_list twice while looking to wakeup the first N
queued reader-tasks. While this can be quite inefficient, it was
there such that a awoken reader would be first and foremost
acknowledged by the lock counter.

Keeping the same logic, we can further benefit from the use of
wake_qs and avoid entirely the first wait_list iteration that sets
the counter as wake_up_process() isn't going to occur right away,
and therefore we maintain the counter->list order of going about
things.

Other than saving cycles with O(n) "scanning", this change also
nicely cleans up a good chunk of __rwsem_mark_wakeup(); both
visually and less tedious to read.

For example, the following improvements where seen on some will
it scale microbenchmarks, on a 48-core Haswell:

                                       v4.7              v4.7-rwsem-v1
  Hmean    signal1-processes-8    5792691.42 (  0.00%)  5771971.04 ( -0.36%)
  Hmean    signal1-processes-12   6081199.96 (  0.00%)  6072174.38 ( -0.15%)
  Hmean    signal1-processes-21   3071137.71 (  0.00%)  3041336.72 ( -0.97%)
  Hmean    signal1-processes-48   3712039.98 (  0.00%)  3708113.59 ( -0.11%)
  Hmean    signal1-processes-79   4464573.45 (  0.00%)  4682798.66 (  4.89%)
  Hmean    signal1-processes-110  4486842.01 (  0.00%)  4633781.71 (  3.27%)
  Hmean    signal1-processes-141  4611816.83 (  0.00%)  4692725.38 (  1.75%)
  Hmean    signal1-processes-172  4638157.05 (  0.00%)  4714387.86 (  1.64%)
  Hmean    signal1-processes-203  4465077.80 (  0.00%)  4690348.07 (  5.05%)
  Hmean    signal1-processes-224  4410433.74 (  0.00%)  4687534.43 (  6.28%)

  Stddev   signal1-processes-8       6360.47 (  0.00%)     8455.31 ( 32.94%)
  Stddev   signal1-processes-12      4004.98 (  0.00%)     9156.13 (128.62%)
  Stddev   signal1-processes-21      3273.14 (  0.00%)     5016.80 ( 53.27%)
  Stddev   signal1-processes-48     28420.25 (  0.00%)    26576.22 ( -6.49%)
  Stddev   signal1-processes-79     22038.34 (  0.00%)    18992.70 (-13.82%)
  Stddev   signal1-processes-110    23226.93 (  0.00%)    17245.79 (-25.75%)
  Stddev   signal1-processes-141     6358.98 (  0.00%)     7636.14 ( 20.08%)
  Stddev   signal1-processes-172     9523.70 (  0.00%)     4824.75 (-49.34%)
  Stddev   signal1-processes-203    13915.33 (  0.00%)     9326.33 (-32.98%)
  Stddev   signal1-processes-224    15573.94 (  0.00%)    10613.82 (-31.85%)

Other runs that saw improvements include context_switch and pipe; and
as expected, this is particularly highlighted on larger thread counts
as it becomes more expensive to walk the list twice.

No change in wakeup ordering or semantics.
Signed-off-by: NDavidlohr Bueso <dbueso@suse.de>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman.Long@hp.com
Cc: dave@stgolabs.net
Cc: jason.low2@hpe.com
Cc: wanpeng.li@hotmail.com
Link: http://lkml.kernel.org/r/1470384285-32163-4-git-send-email-dave@stgolabs.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

Our rwsem code (xadd, at least) is rather well documented, but
there are a few really annoying comments in there that serve
no purpose and we shouldn't bother with them.
Signed-off-by: NDavidlohr Bueso <dbueso@suse.de>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman.Long@hp.com
Cc: dave@stgolabs.net
Cc: jason.low2@hpe.com
Cc: wanpeng.li@hotmail.com
Link: http://lkml.kernel.org/r/1470384285-32163-3-git-send-email-dave@stgolabs.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

We currently return a rw_semaphore structure, which is the
same lock we passed to the function's argument in the first
place. While there are several functions that choose this
return value, the callers use it, for example, for things
like ERR_PTR. This is not the case for __rwsem_mark_wake(),
and in addition this function is really about the lock
waiters (which we know there are at this point), so its
somewhat odd to be returning the sem structure.
Signed-off-by: NDavidlohr Bueso <dbueso@suse.de>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman.Long@hp.com
Cc: dave@stgolabs.net
Cc: jason.low2@hpe.com
Cc: wanpeng.li@hotmail.com
Link: http://lkml.kernel.org/r/1470384285-32163-2-git-send-email-dave@stgolabs.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

The current percpu-rwsem read side is entirely free of serializing insns
at the cost of having a synchronize_sched() in the write path.

The latency of the synchronize_sched() is too high for cgroups. The
commit 1ed13287 talks about the write path being a fairly cold path
but this is not the case for Android which moves task to the foreground
cgroup and back around binder IPC calls from foreground processes to
background processes, so it is significantly hotter than human initiated
operations.

Switch cgroup_threadgroup_rwsem into the slow mode for now to avoid the
problem, hopefully it should not be that slow after another commit:

  80127a39 ("locking/percpu-rwsem: Optimize readers and reduce global impact").

We could just add rcu_sync_enter() into cgroup_init() but we do not want
another synchronize_sched() at boot time, so this patch adds the new helper
which doesn't block but currently can only be called before the first use.
Reported-by: NJohn Stultz <john.stultz@linaro.org>
Reported-by: NDmitry Shmidt <dimitrysh@google.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Colin Cross <ccross@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rom Lemarchand <romlem@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Todd Kjos <tkjos@google.com>
Link: http://lkml.kernel.org/r/20160811165413.GA22807@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

This commit adds Korean version of memory-barriers.txt document.  The
header is referred to HOWTO Korean version.

The translation has started from Feb, 2016 and using a public git
repository[1] to maintain the work.  It's commit history says that it is
following upstream changes as well.

[1] https://github.com/sjp38/linux.doc_trans_membarrierSigned-off-by: NSeongJae Park <sj38.park@gmail.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NByungchul Park <byungchul.park@lge.com>
Acked-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Acked-by: NJonathan Corbet <corbet@lwn.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1470939463-31950-4-git-send-email-paulmck@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

An example result for data dependent write has a typo.  This commit
fixes the wrong typo.
Signed-off-by: NSeongJae Park <sj38.park@gmail.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dhowells@redhat.com
Cc: linux-arch@vger.kernel.org
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1470939463-31950-3-git-send-email-paulmck@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Signed-off-by: NSeongJae Park <sj38.park@gmail.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dhowells@redhat.com
Cc: linux-arch@vger.kernel.org
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1470939463-31950-2-git-send-email-paulmck@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Signed-off-by: NSeongJae Park <sj38.park@gmail.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dhowells@redhat.com
Cc: linux-arch@vger.kernel.org
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1470939463-31950-1-git-send-email-paulmck@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Currently the percpu-rwsem switches to (global) atomic ops while a
writer is waiting; which could be quite a while and slows down
releasing the readers.

This patch cures this problem by ordering the reader-state vs
reader-count (see the comments in __percpu_down_read() and
percpu_down_write()). This changes a global atomic op into a full
memory barrier, which doesn't have the global cacheline contention.

This also enables using the percpu-rwsem with rcu_sync disabled in order
to bias the implementation differently, reducing the writer latency by
adding some cost to readers.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NOleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
[ Fixed modular build. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Currently there are overlap in the pvqspinlock wait_again and
spurious_wakeup stat counters. Because of lock stealing, it is
no longer possible to accurately determine if spurious wakeup has
happened in the queue head.  As they track both the queue node and
queue head status, it is also hard to tell how many of those comes
from the queue head and how many from the queue node.

This patch changes the accounting rules so that spurious wakeup is
only tracked in the queue node. The wait_again count, however, is
only tracked in the queue head when the vCPU failed to acquire the
lock after a vCPU kick. This should give a much better indication of
the wait-kick dynamics in the queue node and the queue head.
Signed-off-by: NWaiman Long <Waiman.Long@hpe.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Douglas Hatch <doug.hatch@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pan Xinhui <xinhui@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott J Norton <scott.norton@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1464713631-1066-2-git-send-email-Waiman.Long@hpe.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Restructure pv_queued_spin_steal_lock() as I found it hard to read.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <waiman.long@hpe.com
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

It's obviously wrong to set stat to NULL. So lets remove it.
Otherwise it is always zero when we check the latency of kick/wake.
Signed-off-by: NPan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NWaiman Long <Waiman.Long@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1468405414-3700-1-git-send-email-xinhui.pan@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

When the lock holder vCPU is racing with the queue head:

   CPU 0 (lock holder)    CPU1 (queue head)
   ===================    =================
   spin_lock();           spin_lock();
    pv_kick_node():        pv_wait_head_or_lock():
                            if (!lp) {
                             lp = pv_hash(lock, pn);
                             xchg(&l->locked, _Q_SLOW_VAL);
                            }
                            WRITE_ONCE(pn->state, vcpu_halted);
     cmpxchg(&pn->state,
      vcpu_halted, vcpu_hashed);
     WRITE_ONCE(l->locked, _Q_SLOW_VAL);
     (void)pv_hash(lock, pn);

In this case, lock holder inserts the pv_node of queue head into the
hash table and set _Q_SLOW_VAL unnecessary. This patch avoids it by
restoring/setting vcpu_hashed state after failing adaptive locking
spinning.
Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NPan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <Waiman.Long@hpe.com>
Link: http://lkml.kernel.org/r/1468484156-4521-1-git-send-email-wanpeng.li@hotmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

This patch aims to get rid of endianness in queued_write_unlock(). We
want to set  __qrwlock->wmode to NULL, however the address is not
&lock->cnts in big endian machine. That causes queued_write_unlock()
write NULL to the wrong field of __qrwlock.

So implement __qrwlock_write_byte() which returns the correct
__qrwlock->wmode address.
Suggested-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NPan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman.Long@hpe.com
Cc: arnd@arndb.de
Cc: boqun.feng@gmail.com
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1468835259-4486-1-git-send-email-xinhui.pan@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Signed-off-by: NIngo Molnar <mingo@kernel.org>

This reverts commit 874f9c7d.

Geert Uytterhoeven reports:
 "This change seems to have an (unintendent?) side-effect.

  Before, pr_*() calls without a trailing newline characters would be
  printed with a newline character appended, both on the console and in
  the output of the dmesg command.

  After this commit, no new line character is appended, and the output
  of the next pr_*() call of the same type may be appended, like in:

    - Truncating RAM at 0x0000000040000000-0x00000000c0000000 to -0x0000000070000000
    - Ignoring RAM at 0x0000000200000000-0x0000000240000000 (!CONFIG_HIGHMEM)
    + Truncating RAM at 0x0000000040000000-0x00000000c0000000 to -0x0000000070000000Ignoring RAM at 0x0000000200000000-0x0000000240000000 (!CONFIG_HIGHMEM)"

Joe Perches says:
 "No, that is not intentional.

  The newline handling code inside vprintk_emit is a bit involved and
  for now I suggest a revert until this has all the same behavior as
  earlier"
Reported-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Requested-by: NJoe Perches <joe@perches.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull tracing fix from Steven Rostedt:
 "Fix tick_stop tracepoint symbols for user export.

  Luiz Capitulino noticed that the tick_stop tracepoint wasn't being
  parsed properly by the tracing user space tools.

  This was due to the TRACE_DEFINE_ENUM() being set to a define, when it
  should have been set to the enum itself.  The define was of the MASK
  that used the BIT to shift.  The BIT was the enum and by adding that,
  everything gets converted nicely.  The MASK is still kept just in case
  it gets converted to an enum in the future"

* tag 'trace-v4.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix tick_stop tracepoint symbols for user export

Merge tag 'gcc-plugin-infrastructure-v4.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull gcc plugin improvements from Kees Cook:
 "Several fixes/improvements for the gcc plugin infrastructure:

   - fix a problem with gcc plugins interfering with cc-option tests.

   - abort more gracefully when gcc plugin headers or compiler support
     is missing.

   - improve the gcc plugin rule generation to be more dynamic, pass
     arguments, and build from subdirectories"

* tag 'gcc-plugin-infrastructure-v4.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  gcc-plugins: Add support for plugin subdirectories
  gcc-plugins: Automate make rule generation
  gcc-plugins: Add support for passing plugin arguments
  gcc-plugins: abort builds cleanly when not supported
  kbuild: no gcc-plugins during cc-option tests

Merge tag 'platform-drivers-x86-v4.8-3' of git://git.infradead.org/users/dvhart/linux-platform-drivers-x86

Pull x86 platform driver update from Darren Hart:
 "dell-wmi: ignore battery remove/insert event"

* tag 'platform-drivers-x86-v4.8-3' of git://git.infradead.org/users/dvhart/linux-platform-drivers-x86:
  dell-wmi: Ignore WMI event 0xe00e

Pull drm fixes from Dave Airlie:
 "This contains a bunch of amdgpu fixes, and some i915 regression fixes.

  It also contains some fixes for an older regression with some EDID
  changes and some 6bpc panels.

  Then there are the lockdep, cirrus and rcar-du regression fixes from
  this window"

* tag 'drm-fixes-for-4.8-rc2' of git://people.freedesktop.org/~airlied/linux:
  drm/cirrus: Fix NULL pointer dereference when registering the fbdev
  drm/edid: Set 8 bpc color depth for displays with "DFP 1.x compliant TMDS".
  drm/i915/dp: Revert "drm/i915/dp: fall back to 18 bpp when sink capability is unknown"
  drm/edid: Add 6 bpc quirk for display AEO model 0.
  drm: Paper over locking inversion after registration rework
  drm: rcar-du: Link HDMI encoder with bridge
  drm/ttm: Wait for a BO to become idle before unbinding it from GTT
  drm/i915/fbdev: Check for the framebuffer before use
  drm/amdgpu: update golden setting of polaris10
  drm/amdgpu: update golden setting of stoney
  drm/amdgpu: update golden setting of polaris11
  drm/amdgpu: update golden setting of carrizo
  drm/amdgpu: update golden setting of iceland
  drm/amd/amdgpu: change pptable output format from ASCII to binary
  drm/amdgpu/ci: add mullins to default case for smc ucode
  drm/amdgpu/gmc7: add missing mullins case
  drm/i915: Never fully mask the the EI up rps interrupt on SNB/IVB
  drm/i915: Wait up to 3ms for the pcu to ack the cdclk change request on SKL

Commit b195d5e2 ("ipr: Wait to do async scan until scsi host is
initialized") fixed async scan for ipr, but broke sync scan for ipr.

This fixes sync scan back up.
Signed-off-by: NBrian King <brking@linux.vnet.ibm.com>
Reported-and-tested-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

To distinguish non-slab pages charged to kmemcg we mark them PageKmemcg,
which sets page->_mapcount to -512.  Currently, we set/clear PageKmemcg
in __alloc_pages_nodemask()/free_pages_prepare() for any page allocated
with __GFP_ACCOUNT, including those that aren't actually charged to any
cgroup, i.e. allocated from the root cgroup context.  To avoid overhead
in case cgroups are not used, we only do that if memcg_kmem_enabled() is
true.  The latter is set iff there are kmem-enabled memory cgroups
(online or offline).  The root cgroup is not considered kmem-enabled.

As a result, if a page is allocated with __GFP_ACCOUNT for the root
cgroup when there are kmem-enabled memory cgroups and is freed after all
kmem-enabled memory cgroups were removed, e.g.

  # no memory cgroups has been created yet, create one
  mkdir /sys/fs/cgroup/memory/test
  # run something allocating pages with __GFP_ACCOUNT, e.g.
  # a program using pipe
  dmesg | tail
  # remove the memory cgroup
  rmdir /sys/fs/cgroup/memory/test

we'll get bad page state bug complaining about page->_mapcount != -1:

  BUG: Bad page state in process swapper/0  pfn:1fd945c
  page:ffffea007f651700 count:0 mapcount:-511 mapping:          (null) index:0x0
  flags: 0x1000000000000000()

To avoid that, let's mark with PageKmemcg only those pages that are
actually charged to and hence pin a non-root memory cgroup.

Fixes: 4949148a ("mm: charge/uncharge kmemcg from generic page allocator paths")
Reported-and-tested-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NVladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The symbols used in the tick_stop tracepoint were not being converted
properly into integers in the trace_stop format file. Instead we had this:

print fmt: "success=%d dependency=%s", REC->success,
    __print_symbolic(REC->dependency, { 0, "NONE" },
     { (1 << TICK_DEP_BIT_POSIX_TIMER), "POSIX_TIMER" },
     { (1 << TICK_DEP_BIT_PERF_EVENTS), "PERF_EVENTS" },
     { (1 << TICK_DEP_BIT_SCHED), "SCHED" },
     { (1 << TICK_DEP_BIT_CLOCK_UNSTABLE), "CLOCK_UNSTABLE" })

User space tools have no idea how to parse "TICK_DEP_BIT_SCHED" or the other
symbols used to do the bit shifting. The reason is that the conversion was
done with using the TICK_DEP_MASK_* symbols which are just macros that
convert to the BIT shift itself (with the exception of NONE, which was
converted properly, because it doesn't use bits, and is defined as zero).

The TICK_DEP_BIT_* needs to be denoted by TRACE_DEFINE_ENUM() in order to
have this properly converted for user space tools to parse this event.

Cc: stable@vger.kernel.org
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Fixes: e6e6cc22 ("nohz: Use enum code for tick stop failure tracing message")
Reported-by: NLuiz Capitulino <lcapitulino@redhat.com>
Tested-by: NLuiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

cirrus_modeset_init() is initializing/registering the emulated fbdev
and, since commit c61b93fe ("drm/atomic: Fix remaining places where
!funcs->best_encoder is valid"), DRM internals can access/test some of
the fields in mode_config->funcs as part of the fbdev registration
process.
Make sure dev->mode_config.funcs is properly set to avoid dereferencing
a NULL pointer.
Reported-by: NMike Marshall <hubcap@omnibond.com>
Reported-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>
Fixes: c61b93fe ("drm/atomic: Fix remaining places where !funcs->best_encoder is valid")
Signed-off-by: NDave Airlie <airlied@redhat.com>

This adds support for building more complex gcc plugins that live in a
subdirectory instead of just in a single source file.
Reported-by: NPaX Team <pageexec@freemail.hu>
Signed-off-by: NEmese Revfy <re.emese@gmail.com>
[kees: clarified commit message]
Signed-off-by: NKees Cook <keescook@chromium.org>

There's no reason to repeat the same names in the Makefile when the .so
files have already been listed. The .o list can be generated from them.
Reported-by: NPaX Team <pageexec@freemail.hu>
Signed-off-by: NEmese Revfy <re.emese@gmail.com>
[kees: clarified commit message]
Signed-off-by: NKees Cook <keescook@chromium.org>

The latent_entropy plugin needs to pass arguments, so this adds the
support.
Signed-off-by: NEmese Revfy <re.emese@gmail.com>
Signed-off-by: NKees Cook <keescook@chromium.org>

When the compiler doesn't support gcc plugins (either due to missing
headers or too old a version), report the problem and abort the build
instead of emitting a warning and letting the build founder with arcane
compiler errors.
Signed-off-by: NKees Cook <keescook@chromium.org>

The gcc-plugins arguments should not be included when performing
cc-option tests.

Steps to reproduce:
1) make mrproper
2) make defconfig
3) enable GCC_PLUGINS, GCC_PLUGIN_CYC_COMPLEXITY
4) enable FUNCTION_TRACER (it will select other options as well)
5) make && make modules

Build errors:
MODPOST 18 modules
ERROR: "__fentry__" [net/netfilter/xt_nat.ko] undefined!
ERROR: "__fentry__" [net/netfilter/xt_mark.ko] undefined!
ERROR: "__fentry__" [net/netfilter/xt_addrtype.ko] undefined!
ERROR: "__fentry__" [net/netfilter/xt_LOG.ko] undefined!
ERROR: "__fentry__" [net/netfilter/nf_nat_sip.ko] undefined!
ERROR: "__fentry__" [net/netfilter/nf_nat_irc.ko] undefined!
ERROR: "__fentry__" [net/netfilter/nf_nat_ftp.ko] undefined!
ERROR: "__fentry__" [net/netfilter/nf_nat.ko] undefined!
Reported-by: NLaura Abbott <labbott@redhat.com>
Signed-off-by: NEmese Revfy <re.emese@gmail.com>
[kees: renamed variable, clarified commit message]
Signed-off-by: NKees Cook <keescook@chromium.org>

According to E-EDID spec 1.3, table 3.9, a digital video sink with the
"DFP 1.x compliant TMDS" bit set is "signal compatible with VESA DFP 1.x
TMDS CRGB, 1 pixel / clock, up to 8 bits / color MSB aligned".

For such displays, the DFP spec 1.0, section 3.10 "EDID support" says:

"If the DFP monitor only supports EDID 1.X (1.1, 1.2, etc.)
 without extensions, the host will make the following assumptions:

 1. 24-bit MSB-aligned RGB TFT
 2. DE polarity is active high
 3. H and V syncs are active high
 4. Established CRT timings will be used
 5. Dithering will not be enabled on the host"

So if we don't know the bit depth of the display from additional
colorimetry info we should assume 8 bpc / 24 bpp by default.

This patch adds info->bpc = 8 assignement for that case.
Signed-off-by: NMario Kleiner <mario.kleiner.de@gmail.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

This reverts commit 013dd9e0
("drm/i915/dp: fall back to 18 bpp when sink capability is unknown")

This commit introduced a regression into stable kernels,
as it reduces output color depth to 6 bpc for any video
sink connected to a Displayport connector if that sink
doesn't report a specific color depth via EDID, or if
our EDID parser doesn't actually recognize the proper
bpc from EDID.

Affected are active DisplayPort->VGA converters and
active DisplayPort->DVI converters. Both should be
able to handle 8 bpc, but are degraded to 6 bpc with
this patch.

The reverted commit was meant to fix
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=105331

A followup patch implements a fix for that specific bug,
which is caused by a faulty EDID of the affected DP panel
by adding a new EDID quirk for that panel.

DP 18 bpp fallback handling and other improvements to
DP sink bpc detection will be handled for future
kernels in a separate series of patches.

Please backport to stable.
Signed-off-by: NMario Kleiner <mario.kleiner.de@gmail.com>
Acked-by: NJani Nikula <jani.nikula@intel.com>
Cc: stable@vger.kernel.org
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Bugzilla https://bugzilla.kernel.org/show_bug.cgi?id=105331
reports that the "AEO model 0" display is driven with 8 bpc
without dithering by default, which looks bad because that
panel is apparently a 6 bpc DP panel with faulty EDID.

A fix for this was made by commit 013dd9e0
("drm/i915/dp: fall back to 18 bpp when sink capability is unknown").

That commit triggers new regressions in precision for DP->DVI and
DP->VGA displays. A patch is out to revert that commit, but it will
revert video output for the AEO model 0 panel to 8 bpc without
dithering.

The EDID 1.3 of that panel, as decoded from the xrandr output
attached to that bugzilla bug report, is somewhat faulty, and beyond
other problems also sets the "DFP 1.x compliant TMDS" bit, which
according to DFP spec means to drive the panel with 8 bpc and
no dithering in absence of other colorimetry information.

Try to make the original bug reporter happy despite the
faulty EDID by adding a quirk to mark that panel as 6 bpc,
so 6 bpc output with dithering creates a nice picture.

Tested by injecting the edid from the fdo bug into a DP connector
via drm_kms_helper.edid_firmware and verifying the 6 bpc + dithering
is selected.

This patch should be backported to stable.
Signed-off-by: NMario Kleiner <mario.kleiner.de@gmail.com>
Cc: stable@vger.kernel.org
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Pull lkdtm update from Kees Cook:
 "Fix rebuild problem with LKDTM's rodata test"

[ This, and the usercopy branch, both came in before the merge window
  closed, but ended up in my 'need to look more' queue and thus got
  merged only after rc1 was out ]

* tag 'lkdtm-v4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  lkdtm: Fix targets for objcopy usage
  lkdtm: fix false positive warning from -Wmaybe-uninitialized

Pull usercopy protection from Kees Cook:
 "Tbhis implements HARDENED_USERCOPY verification of copy_to_user and
  copy_from_user bounds checking for most architectures on SLAB and
  SLUB"

* tag 'usercopy-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  mm: SLUB hardened usercopy support
  mm: SLAB hardened usercopy support
  s390/uaccess: Enable hardened usercopy
  sparc/uaccess: Enable hardened usercopy
  powerpc/uaccess: Enable hardened usercopy
  ia64/uaccess: Enable hardened usercopy
  arm64/uaccess: Enable hardened usercopy
  ARM: uaccess: Enable hardened usercopy
  x86/uaccess: Enable hardened usercopy
  mm: Hardened usercopy
  mm: Implement stack frame object validation
  mm: Add is_migrate_cma_page

When I initially added the unsafe_[get|put]_user() helpers in commit
5b24a7a2 ("Add 'unsafe' user access functions for batched
accesses"), I made the mistake of modeling the interface on our
traditional __[get|put]_user() functions, which return zero on success,
or -EFAULT on failure.

That interface is fairly easy to use, but it's actually fairly nasty for
good code generation, since it essentially forces the caller to check
the error value for each access.

In particular, since the error handling is already internally
implemented with an exception handler, and we already use "asm goto" for
various other things, we could fairly easily make the error cases just
jump directly to an error label instead, and avoid the need for explicit
checking after each operation.

So switch the interface to pass in an error label, rather than checking
the error value in the caller.  Best do it now before we start growing
more users (the signal handling code in particular would be a good place
to use the new interface).

So rather than

	if (unsafe_get_user(x, ptr))
		... handle error ..

the interface is now

	unsafe_get_user(x, ptr, label);

where an error during the user mode fetch will now just cause a jump to
'label' in the caller.

Right now the actual _implementation_ of this all still ends up being a
"if (err) goto label", and does not take advantage of any exception
label tricks, but for "unsafe_put_user()" in particular it should be
fairly straightforward to convert to using the exception table model.

Note that "unsafe_get_user()" is much harder to convert to a clever
exception table model, because current versions of gcc do not allow the
use of "asm goto" (for the exception) with output values (for the actual
value to be fetched).  But that is hopefully not a limitation in the
long term.

[ Also note that it might be a good idea to switch unsafe_get_user() to
  actually _return_ the value it fetches from user space, but this
  commit only changes the error handling semantics ]
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In commit 874f9c7d ("printk: create pr_<level> functions"), new
pr_level defines were added to printk.c.

These new defines are guarded by an #ifdef CONFIG_PRINTK - however,
there is already a surrounding #ifdef CONFIG_PRINTK starting a lot
earlier in line 249 which means the newly introduced #ifdef is
unnecessary.

Let's remove it to avoid confusion.
Signed-off-by: NAndreas Ziegler <andreas.ziegler@fau.de>
Cc: Joe Perches <joe@perches.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

WMI event 0xe00e is received when battery was removed or inserted.
Signed-off-by: NPali Rohár <pali.rohar@gmail.com>
Signed-off-by: NDarren Hart <dvhart@linux.intel.com>

The caller expects %rdi to remain intact, push+pop it make that happen.

Fixes the following kind of explosions on my core2duo machine when
trying to reboot or shut down:

  general protection fault: 0000 [#1] PREEMPT SMP
  Modules linked in: i915 i2c_algo_bit drm_kms_helper cfbfillrect syscopyarea cfbimgblt sysfillrect sysimgblt fb_sys_fops cfbcopyarea drm netconsole configfs binfmt_misc iTCO_wdt psmouse pcspkr snd_hda_codec_idt e100 coretemp hwmon snd_hda_codec_generic i2c_i801 mii i2c_smbus lpc_ich mfd_core snd_hda_intel uhci_hcd snd_hda_codec snd_hwdep snd_hda_core ehci_pci 8250 ehci_hcd snd_pcm 8250_base usbcore evdev serial_core usb_common parport_pc parport snd_timer snd soundcore
  CPU: 0 PID: 3070 Comm: reboot Not tainted 4.8.0-rc1-perf-dirty #69
  Hardware name:                  /D946GZIS, BIOS TS94610J.86A.0087.2007.1107.1049 11/07/2007
  task: ffff88012a0b4080 task.stack: ffff880123850000
  RIP: 0010:[<ffffffff81003c92>]  [<ffffffff81003c92>] x86_perf_event_update+0x52/0xc0
  RSP: 0018:ffff880123853b60  EFLAGS: 00010087
  RAX: 0000000000000001 RBX: ffff88012fc0a3c0 RCX: 000000000000001e
  RDX: 0000000000000000 RSI: 0000000040000000 RDI: ffff88012b014800
  RBP: ffff880123853b88 R08: ffffffffffffffff R09: 0000000000000000
  R10: ffffea0004a012c0 R11: ffffea0004acedc0 R12: ffffffff80000001
  R13: ffff88012b0149c0 R14: ffff88012b014800 R15: 0000000000000018
  FS:  00007f8b155cd700(0000) GS:ffff88012fc00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f8b155f5000 CR3: 000000012a2d7000 CR4: 00000000000006f0
  Stack:
   ffff88012fc0a3c0 ffff88012b014800 0000000000000004 0000000000000001
   ffff88012fc1b750 ffff880123853bb0 ffffffff81003d59 ffff88012b014800
   ffff88012fc0a3c0 ffff88012b014800 ffff880123853bd8 ffffffff81003e13
  Call Trace:
   [<ffffffff81003d59>] x86_pmu_stop+0x59/0xd0
   [<ffffffff81003e13>] x86_pmu_del+0x43/0x140
   [<ffffffff8111705d>] event_sched_out.isra.105+0xbd/0x260
   [<ffffffff8111738d>] __perf_remove_from_context+0x2d/0xb0
   [<ffffffff8111745d>] __perf_event_exit_context+0x4d/0x70
   [<ffffffff810c8826>] generic_exec_single+0xb6/0x140
   [<ffffffff81117410>] ? __perf_remove_from_context+0xb0/0xb0
   [<ffffffff81117410>] ? __perf_remove_from_context+0xb0/0xb0
   [<ffffffff810c898f>] smp_call_function_single+0xdf/0x140
   [<ffffffff81113d27>] perf_event_exit_cpu_context+0x87/0xc0
   [<ffffffff81113d73>] perf_reboot+0x13/0x40
   [<ffffffff8107578a>] notifier_call_chain+0x4a/0x70
   [<ffffffff81075ad7>] __blocking_notifier_call_chain+0x47/0x60
   [<ffffffff81075b06>] blocking_notifier_call_chain+0x16/0x20
   [<ffffffff81076a1d>] kernel_restart_prepare+0x1d/0x40
   [<ffffffff81076ae2>] kernel_restart+0x12/0x60
   [<ffffffff81076d56>] SYSC_reboot+0xf6/0x1b0
   [<ffffffff811a823c>] ? mntput_no_expire+0x2c/0x1b0
   [<ffffffff811a83e4>] ? mntput+0x24/0x40
   [<ffffffff811894fc>] ? __fput+0x16c/0x1e0
   [<ffffffff811895ae>] ? ____fput+0xe/0x10
   [<ffffffff81072fc3>] ? task_work_run+0x83/0xa0
   [<ffffffff81001623>] ? exit_to_usermode_loop+0x53/0xc0
   [<ffffffff8100105a>] ? trace_hardirqs_on_thunk+0x1a/0x1c
   [<ffffffff81076e6e>] SyS_reboot+0xe/0x10
   [<ffffffff814c4ba5>] entry_SYSCALL_64_fastpath+0x18/0xa3
  Code: 7c 4c 8d af c0 01 00 00 49 89 fe eb 10 48 09 c2 4c 89 e0 49 0f b1 55 00 4c 39 e0 74 35 4d 8b a6 c0 01 00 00 41 8b 8e 60 01 00 00 <0f> 33 8b 35 6e 02 8c 00 48 c1 e2 20 85 f6 7e d2 48 89 d3 89 cf
  RIP  [<ffffffff81003c92>] x86_perf_event_update+0x52/0xc0
   RSP <ffff880123853b60>
  ---[ end trace 7ec95181faf211be ]---
  note: reboot[3070] exited with preempt_count 2

Cc: Borislav Petkov <bp@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Fixes: f5967101 ("x86/hweight: Get rid of the special calling convention")
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>