The rdpmc instruction is faster than the equivelant rdmsr call,
so use it when possible in the kernel.

The perfctr kernel patches did this, after extensive testing showed
rdpmc to always be faster (One can look in etc/costs in the perfctr-2.6
package to see a historical list of the overhead).

I have done some tests on a 3.2 kernel, the kernel module I used
was included in the first posting of this patch:

                   rdmsr           rdpmc
 Core2 T9900:      203.9 cycles     30.9 cycles
 AMD fam0fh:        56.2 cycles      9.8 cycles
 Atom 6/28/2:      129.7 cycles     50.6 cycles

The speedup of using rdpmc is large.

[ It's probably possible (and desirable) to do this without
  requiring a new field in the hw_perf_event structure, but
  the fixed events make this tricky. ]
Signed-off-by: NVince Weaver <vweaver1@eecs.utk.edu>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/alpine.DEB.2.00.1203011724030.26934@cl320.eecs.utk.eduSigned-off-by: NIngo Molnar <mingo@kernel.org>

Add a version of rdpmc() that directly reads into a u64
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1338944211-28275-4-git-send-email-andi@firstfloor.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Move the wrmslr() debug wrapper to the common header now that all the
include games are gone. Also clean it up a bit to avoid multiple
evaluation of the argument.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-l4gkfnivwv4yi5mqxjlovymx@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Eliminate a conflict in a patch I am going to apply.
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Afaict there's no need to (incompletely) iterate the
MEM_UOPS_RETIRED.* umask state.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1338884803.28282.153.camel@twinsSigned-off-by: NIngo Molnar <mingo@kernel.org>

Implement rudimentary IVB perf support. The SDM states its identical
to SNB with exception of the exact event tables, but a quick look
suggests they're similar enough.

Also mark SNB-EP as broken for now.
Requested-and-tested-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1338884803.28282.153.camel@twinsSigned-off-by: NIngo Molnar <mingo@kernel.org>

Now that there's finally a chip with working PEBS (IvyBridge), we can
enable the hardware and implement cycles:p for SNB/IVB.

Cc: Stephane Eranian <eranian@google.com>
Requested-and-tested-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1338884803.28282.153.camel@twinsSigned-off-by: NIngo Molnar <mingo@kernel.org>

Zheng Yan reported that event group validation can wreck event state
when Intel extra_reg allocation changes event state.

Validation shouldn't change any persistent state. Cloning events in
validate_{event,group}() isn't really pretty either, so add a few
special cases to avoid modifying the event state.

The code is restructured to minimize the special case impact.
Reported-by: NZheng Yan <zheng.z.yan@linux.intel.com>
Acked-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1338903031.28282.175.camel@twinsSigned-off-by: NIngo Molnar <mingo@kernel.org>

Kill the no longer needed uprobes_srcu/uprobe_srcu_id code.

It doesn't really work anyway. synchronize_srcu() can only
synchronize with the code "inside" the
srcu_read_lock/srcu_read_unlock section, while
uprobe_pre_sstep_notifier() does srcu_read_lock() _after_ we
already hit the breakpoint.

I guess this probably works "in practice". synchronize_srcu() is
slow and it implies synchronize_sched(), and the probed task
enters the non- preemptible section at the start of exception
handler. Still this is not right at least in theory, and
task->uprobe_srcu_id blows task_struct.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Acked-by: NSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120529193008.GG8057@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Currently handle_swbp() assumes that it can't race with
unregister, so it roughly does:

	if (find_uprobe(vaddr))
		process_uprobe();
	else
		send_sig(SIGTRAP);

This relies on the not-really-working uprobes_srcu code we are
going to remove, see the next patch.

With this patch we rely on the result of
is_swbp_at_addr(bp_vaddr) if find_uprobe() fails.

If is_swbp == 1, then we hit the normal int3, we should send
SIGTRAP.

If is_swbp == 0, we raced with uprobe_unregister(), we simply
restart this insn again.

The "difficult" case is is_swbp == -EFAULT, when we can't read
this memory. In this case I think we should restart too, and
this is more correct compared to the current code which sends
SIGTRAP.

Ignoring ENOMEM/etc from get_user_pages(), this can only happen
if another thread unmaps this memory before find_active_uprobe()
takes mmap_sem. It would be better to pretend it was unmapped
before this insn was executed, restart, and get SIGSEGV.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Acked-by: NSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120529192947.GF8057@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Change register_for_each_vma() to take mm->mmap_sem for writing.
This is a bit unfortunate but hopefully not too bad, this is the
slow path anyway.

This is needed to ensure that find_active_uprobe() can not race
with uprobe_register() which adds the new bp at the same
bp_vaddr, after find_uprobe() fails and before
is_swbp_at_addr_fast() checks the memory.

IOW, this is needed to ensure that if find_active_uprobe()
returns NULL but is_swbp == true, we can safely assume that it
was the "normal" int3 and we should send SIGTRAP.

There is another reason for this change. We are going to replace
uprobes_state->count with MMF_ flags set by register/unregister
and cleared by find_active_uprobe(), and set/clear shouldn't
race with each other.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Acked-by: NSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120529192928.GE8057@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

A separate patch to simplify the review, and for the
documentation.

The patch adds another "int *is_swbp" argument to
find_active_uprobe(), so far its only caller doesn't use this
info.

With this patch find_active_uprobe() additionally does:

	- if find_vma() + ->vm_start check fails, *is_swbp = -EFAULT

	- otherwise, if valid_vma() + find_uprobe() fails, it holds
	  the result of is_swbp_at_addr(), can be negative too. The
	  latter is only possible if we raced with another thread
	  which did munmap/etc after we hit this bp.

IOW. If find_active_uprobe(&is_swbp) returns NULL, the caller
can look at is_swbp to figure out whether the current insn is bp
or not, or detect the race with another thread if it is
negative.

Note: I think that performance-wise this change is fine. This
adds is_swbp_at_addr(), but only if we raced with
uprobe_unregister() or if we hit the "normal" int3 but this mm
has uprobes as well. And even in this case the slow
read_opcode() path is very unlikely, this insn recently
triggered do_int3(), __copy_from_user_inatomic() shouldn't fail
in the likely case.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Acked-by: NSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120529192914.GD8057@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

No functional changes. Move the "find uprobe" code from
handle_swbp() to the new helper, find_active_uprobe().

Note: with or without this change, the find-active-uprobe logic
is not exactly right. We can race with another thread which
unmaps the memory with the valid uprobe before we take
mm->mmap_sem. We can't find this uprobe simply because
find_vma() fails. In this case we wrongly assume that this trap
was not caused by uprobe and send the erroneous SIGTRAP. See the
next changes.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Acked-by: NSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120529192857.GC8057@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

set_orig_insn()->read_opcode() should not fail if the probed
task did mprotect() after uprobe_register(), change it to use
FOLL_FORCE. Without FOLL_WRITE this doesn't have any "side"
effect but allows to read the !VM_READ memory.

There is another reason for this change, we are going to use
is_swbp_at_addr() from handle_swbp() which can race with another
thread doing mprotect().
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Acked-by: NSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120529192759.GB8057@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Change is_swbp_at_addr() to try to avoid the costly
read_opcode() if mm == current->mm, __copy_from_user_inatomic()
should succeed in the likely case.

Currently this optimization is not important, but we are going
to add more is_swbp_at_addr(current->mm) callers.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Acked-by: NSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120529192744.GA8057@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Signed-off-by: NArun Sharma <asharma@fb.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1334961696-19580-5-git-send-email-asharma@fb.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Signed-off-by: NArun Sharma <asharma@fb.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1334961696-19580-4-git-send-email-asharma@fb.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Stack depth of 255 seems excessive, given that copy_from_user_nmi()
could be slow.
Signed-off-by: NArun Sharma <asharma@fb.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1334961696-19580-3-git-send-email-asharma@fb.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Without this patch, applications with two different stack
regions (eg: native stack vs JIT stack) get truncated
callchains even when RBP chaining is present. GDB shows proper
stack traces and the frame pointer chaining is intact.

This patch disables the (fp < RSP) check, hoping that other checks
in the code save the day for us. In our limited testing, this
didn't seem to break anything.

In the long term, we could potentially have userspace advise
the kernel on the range of valid stack addresses, so we don't
spend a lot of time unwinding from bogus addresses.
Signed-off-by: NArun Sharma <asharma@fb.com>
CC: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-perf-users@vger.kernel.org
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1334961696-19580-2-git-send-email-asharma@fb.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Afaict there's no need to (incompletely) iterate the
MEM_UOPS_RETIRED.* umask state.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1338884803.28282.153.camel@twinsSigned-off-by: NIngo Molnar <mingo@kernel.org>

Implement rudimentary IVB perf support. The SDM states its identical
to SNB with exception of the exact event tables, but a quick look
suggests they're similar enough.

Also mark SNB-EP as broken for now.
Requested-and-tested-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1338884803.28282.153.camel@twinsSigned-off-by: NIngo Molnar <mingo@kernel.org>

Now that there's finally a chip with working PEBS (IvyBridge), we can
enable the hardware and implement cycles:p for SNB/IVB.

Cc: Stephane Eranian <eranian@google.com>
Requested-and-tested-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1338884803.28282.153.camel@twinsSigned-off-by: NIngo Molnar <mingo@kernel.org>

Zheng Yan reported that event group validation can wreck event state
when Intel extra_reg allocation changes event state.

Validation shouldn't change any persistent state. Cloning events in
validate_{event,group}() isn't really pretty either, so add a few
special cases to avoid modifying the event state.

The code is restructured to minimize the special case impact.
Reported-by: NZheng Yan <zheng.z.yan@linux.intel.com>
Acked-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1338903031.28282.175.camel@twinsSigned-off-by: NIngo Molnar <mingo@kernel.org>

Fix the x86 instruction decoder to decode bsr/bsf/jmpe with
operand-size prefix (66h). This fixes the test case failure
reported by Linus, attached below.

bsf/bsr/jmpe have a special encoding. Opcode map in
Intel Software Developers Manual vol2 says they have
TZCNT/LZCNT variants if it has F3h prefix. However, there
is no information if it has other 66h or F2h prefixes.
Current instruction decoder supposes that those are
bad instructions, but it actually accepts at least
operand-size prefixes.

H. Peter Anvin further explains:

 " TZCNT/LZCNT are F3 + BSF/BSR exactly because the F2 and
   F3 prefixes have historically been no-ops with most instructions.
   This allows software to unconditionally use the prefixed versions
   and get TZCNT/LZCNT on the processors that have them if they don't
   care about the difference. "

This fixes errors reported by test_get_len:

  Warning: arch/x86/tools/test_get_len found difference at <em_bsf>:ffffffff81036d87
  Warning: ffffffff81036de5:	66 0f bc c2          	bsf    %dx,%ax
  Warning: objdump says 4 bytes, but insn_get_length() says 3
  Warning: arch/x86/tools/test_get_len found difference at <em_bsr>:ffffffff81036ea6
  Warning: ffffffff81036f04:	66 0f bd c2          	bsr    %dx,%ax
  Warning: objdump says 4 bytes, but insn_get_length() says 3
  Warning: decoded and checked 13298882 instructions with 2 warnings
Reported-by: NLinus Torvalds <torvalds@linux-foundation.org>
Reported-by: NPekka Enberg <penberg@kernel.org>
Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <yrl.pp-manager.tt@hitachi.com>
Link: http://lkml.kernel.org/r/20120604150911.22338.43296.stgit@localhost.localdomainSigned-off-by: NIngo Molnar <mingo@kernel.org>

Merge tag 'perf-urgent-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent

Pull perf fixes from Arnaldo Carvalho de Melo:

 * Endianness fixes from Jiri Olsa

 * Fixes for make perf tarball

 * Fix for DSO name in perf script callchains, from David Ahern

 * Segfault fixes for perf top --callchain, from Namhyung Kim

 * Minor function result fixes from Srikar Dronamraju

 * Add missing 3rd ioctl parameter, from Namhyung Kim

 * Fix pager usage in minimal embedded systems, from Avik Sil
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Pull fuse updates from Miklos Szeredi.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: fix blksize calculation
  fuse: fix stat call on 32 bit platforms
  fuse: optimize fallocate on permanent failure
  fuse: add FALLOCATE operation
  fuse: Convert to kstrtoul_from_user

Pull scheduler fixes from Ingo Molnar.

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Remove NULL assignment of dattr_cur
  sched: Remove the last NULL entry from sched_feat_names
  sched: Make sched_feat_names const
  sched/rt: Fix SCHED_RR across cgroups
  sched: Move nr_cpus_allowed out of 'struct sched_rt_entity'
  sched: Make sure to not re-read variables after validation
  sched: Fix SD_OVERLAP
  sched: Don't try allocating memory from offline nodes
  sched/nohz: Fix rq->cpu_load calculations some more
  sched/x86: Use cpu_llc_shared_mask(cpu) for coregroup_mask

Pull signal and vfs compile breakage fixes from Al Viro.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
  fixups for signal breakage

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  nommu: fix compilation of nommu.c

Pull cifs fixes from Steve French.

* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
  CIFS: Move get_next_mid to ops struct
  CIFS: Make accessing is_valid_oplock/dump_detail ops struct field safe
  CIFS: Improve identation in cifs_unlock_range
  CIFS: Fix possible wrong memory allocation

Obvious brainos spotted by Geert.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Compiling 3.5-rc1 for nommu targets gives:

  CC      mm/nommu.o
mm/nommu.c: In function ‘sys_mmap_pgoff’:
mm/nommu.c:1489:2: error: ‘ret’ undeclared (first use in this function)
mm/nommu.c:1489:2: note: each undeclared identifier is reported only once for each function it appears in

It is trivially fixed by replacing 'ret' with the local variable that is
already defined for the return value 'retval'.
Signed-off-by: NGreg Ungerer <gerg@uclinux.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Pull frontswap feature from Konrad Rzeszutek Wilk:
 "Frontswap provides a "transcendent memory" interface for swap pages.
  In some environments, dramatic performance savings may be obtained
  because swapped pages are saved in RAM (or a RAM-like device) instead
  of a swap disk.  This tag provides the basic infrastructure along with
  some changes to the existing backends."

Fix up trivial conflict in mm/Makefile due to removal of swap token code
changing a line next to the new frontswap entry.

This pull request came in before the merge window even opened, it got
delayed to after the merge window by me just wanting to make sure it had
actual users.  Apparently IBM is using this on their embedded side, and
Jan Beulich says that it's already made available for SLES and OpenSUSE
users.

Also acked by Rik van Riel, and Konrad points to other people liking it
too.  So in it goes.

By Dan Magenheimer (4) and Konrad Rzeszutek Wilk (2)
via Konrad Rzeszutek Wilk
* tag 'stable/frontswap.v16-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/mm:
  frontswap: s/put_page/store/g s/get_page/load
  MAINTAINER: Add myself for the frontswap API
  mm: frontswap: config and doc files
  mm: frontswap: core frontswap functionality
  mm: frontswap: core swap subsystem hooks and headers
  mm: frontswap: add frontswap header file

Merge branches 'irq-urgent-for-linus' and 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull irq and smpboot updates from Thomas Gleixner:
 "Just cleanup patches with no functional change and a fix for suspend
  issues."

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq: Introduce irq_do_set_affinity() to reduce duplicated code
  genirq: Add IRQS_PENDING for nested and simple irq

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  smpboot, idle: Fix comment mismatch over idle_threads_init()
  smpboot, idle: Optimize calls to smp_processor_id() in idle_threads_init()

Pull timer updates from Thomas Gleixner:
 "The clocksource driver is pure hardware enablement and the skew option
  is default off, well tested and non dangerous."

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tick: Move skew_tick option into the HIGH_RES_TIMER section
  clocksource: em_sti: Add DT support
  clocksource: em_sti: Emma Mobile STI driver
  clockevents: Make clockevents_config() a global symbol
  tick: Add tick skew boot option

Cyrill Gorcunov reports that I broke the fdinfo files with commit
30a08bf2 ("proc: move fd symlink i_mode calculations into
tid_fd_revalidate()"), and he's quite right.

The tid_fd_revalidate() function is not just used for the <tid>/fd
symlinks, it's also used for the <tid>/fdinfo/<fd> files, and the
permission model for those are different.

So do the dynamic symlink permission handling just for symlinks, making
the fdinfo files once more appear as the proper regular files they are.

Of course, Al Viro argued (probably correctly) that we shouldn't do the
symlink permission games at all, and make the symlinks always just be
the normal 'lrwxrwxrwx'.  That would have avoided this issue too, but
since somebody noticed that the permissions had changed (which was the
reason for that original commit 30a08bf2 in the first place), people
do apparently use this feature.

[ Basically, you can use the symlink permission data as a cheap "fdinfo"
  replacement, since you see whether the file is open for reading and/or
  writing by just looking at st_mode of the symlink.  So the feature
  does make sense, even if the pain it has caused means we probably
  shouldn't have done it to begin with. ]
Reported-and-tested-by: NCyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Should be 'exynos5_xxx' instead of 'exonys5_xxx'.

It happened at the commit 30b84288 ("Merge tag 'soc2' of
git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc")
during v3.5 merge window.
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>
[ My bad  - Linus ]
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull some left-over PM patches from Rafael J. Wysocki.

* 'pm-acpi' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / PM: Make acpi_pm_device_sleep_state() follow the specification
  ACPI / PM: Make __acpi_bus_get_power() cover D3cold correctly
  ACPI / PM: Fix error messages in drivers/acpi/bus.c
  rtc-cmos / PM: report wakeup event on ACPI RTC alarm
  ACPI / PM: Generate wakeup events on fixed power button

This reverts commit 5ceb9ce6.

That commit seems to be the cause of the mm compation list corruption
issues that Dave Jones reported.  The locking (or rather, absense
there-of) is dubious, as is the use of the 'page' variable once it has
been found to be outside the pageblock range.

So revert it for now, we can re-visit this for 3.6.  If we even need to:
as Minchan Kim says, "The patch wasn't a bug fix and even test workload
was very theoretical".
Reported-and-tested-by: NDave Jones <davej@redhat.com>
Acked-by: NHugh Dickins <hughd@google.com>
Acked-by: NKOSAKI Motohiro <kosaki.motohiro@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

New tmpfs use of !PageUptodate pages for fallocate() is triggering the
WARNING: at mm/page-writeback.c:1990 when __set_page_dirty_nobuffers()
is called from migrate_page_copy() for compaction.

It is anomalous that migration should use __set_page_dirty_nobuffers()
on an address_space that does not participate in dirty and writeback
accounting; and this has also been observed to insert surprising dirty
tags into a tmpfs radix_tree, despite tmpfs not using tags at all.

We should probably give migrate_page_copy() a better way to preserve the
tag and migrate accounting info, when mapping_cap_account_dirty().  But
that needs some more work: so in the interim, avoid the warning by using
a simple SetPageDirty on PageSwapBacked pages.
Reported-and-tested-by: NDave Jones <davej@redhat.com>
Signed-off-by: NHugh Dickins <hughd@google.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The comment above it says "Stat data, not accessed from path walking",
but in fact some of inode fields we use for the common stat data was way
down at the end of the inode, causing unnecessary cache misses for the
common stat operations.

The inode structure is pretty big, and this can change padding depending
on field width, but at least on the common 64-bit configurations this
doesn't change the size.  Some of our inode layout has historically been
to tro to avoid unnecessary padding fields, but cache locality is at
least as important for layout, if not more.

Noticed by looking at kernel profiles, and noticing that the "i_blkbits"
access stood out like a sore thumb.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>