Commit Graph

4072 Commits

Author SHA1 Message Date
Jeremy Fitzhardinge
96f853eaa8 x86, ticketlock: Add slowpath logic
Maintain a flag in the LSB of the ticket lock tail which indicates
whether anyone is in the lock slowpath and may need kicking when
the current holder unlocks.  The flags are set when the first locker
enters the slowpath, and cleared when unlocking to an empty queue (ie,
no contention).

In the specific implementation of lock_spinning(), make sure to set
the slowpath flags on the lock just before blocking.  We must do
this before the last-chance pickup test to prevent a deadlock
with the unlocker:

Unlocker			Locker
				test for lock pickup
					-> fail
unlock
test slowpath
	-> false
				set slowpath flags
				block

Whereas this works in any ordering:

Unlocker			Locker
				set slowpath flags
				test for lock pickup
					-> fail
				block
unlock
test slowpath
	-> true, kick

If the unlocker finds that the lock has the slowpath flag set but it is
actually uncontended (ie, head == tail, so nobody is waiting), then it
clears the slowpath flag.

The unlock code uses a locked add to update the head counter.  This also
acts as a full memory barrier so that its safe to subsequently
read back the slowflag state, knowing that the updated lock is visible
to the other CPUs.  If it were an unlocked add, then the flag read may
just be forwarded from the store buffer before it was visible to the other
CPUs, which could result in a deadlock.

Unfortunately this means we need to do a locked instruction when
unlocking with PV ticketlocks.  However, if PV ticketlocks are not
enabled, then the old non-locked "add" is the only unlocking code.

Note: this code relies on gcc making sure that unlikely() code is out of
line of the fastpath, which only happens when OPTIMIZE_SIZE=n.  If it
doesn't the generated code isn't too bad, but its definitely suboptimal.

Thanks to Srivatsa Vaddagiri for providing a bugfix to the original
version of this change, which has been folded in.
Thanks to Stephan Diestelhorst for commenting on some code which relied
on an inaccurate reading of the x86 memory ordering rules.

Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Link: http://lkml.kernel.org/r/1376058122-8248-11-git-send-email-raghavendra.kt@linux.vnet.ibm.com
Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Stephan Diestelhorst <stephan.diestelhorst@amd.com>
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2013-08-09 07:54:00 -07:00
Jeremy Fitzhardinge
4a1ed4ca68 x86, pvticketlock: When paravirtualizing ticket locks, increment by 2
Increment ticket head/tails by 2 rather than 1 to leave the LSB free
to store a "is in slowpath state" bit.  This halves the number
of possible CPUs for a given ticket size, but this shouldn't matter
in practice - kernels built for 32k+ CPU systems are probably
specially built for the hardware rather than a generic distro
kernel.

Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Link: http://lkml.kernel.org/r/1376058122-8248-9-git-send-email-raghavendra.kt@linux.vnet.ibm.com
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: Attilio Rao <attilio.rao@citrix.com>
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2013-08-09 07:53:50 -07:00
Jeremy Fitzhardinge
354714dd26 x86, pvticketlock: Use callee-save for lock_spinning
Although the lock_spinning calls in the spinlock code are on the
uncommon path, their presence can cause the compiler to generate many
more register save/restores in the function pre/postamble, which is in
the fast path.  To avoid this, convert it to using the pvops callee-save
calling convention, which defers all the save/restores until the actual
function is called, keeping the fastpath clean.

Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Link: http://lkml.kernel.org/r/1376058122-8248-8-git-send-email-raghavendra.kt@linux.vnet.ibm.com
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: Attilio Rao <attilio.rao@citrix.com>
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2013-08-09 07:53:44 -07:00
Jeremy Fitzhardinge
b798df09f9 x86, ticketlock: Collapse a layer of functions
Now that the paravirtualization layer doesn't exist at the spinlock
level any more, we can collapse the __ticket_ functions into the arch_
functions.

Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Link: http://lkml.kernel.org/r/1376058122-8248-4-git-send-email-raghavendra.kt@linux.vnet.ibm.com
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: Attilio Rao <attilio.rao@citrix.com>
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2013-08-09 07:53:14 -07:00
Jeremy Fitzhardinge
545ac13892 x86, spinlock: Replace pv spinlocks with pv ticketlocks
Rather than outright replacing the entire spinlock implementation in
order to paravirtualize it, keep the ticket lock implementation but add
a couple of pvops hooks on the slow patch (long spin on lock, unlocking
a contended lock).

Ticket locks have a number of nice properties, but they also have some
surprising behaviours in virtual environments.  They enforce a strict
FIFO ordering on cpus trying to take a lock; however, if the hypervisor
scheduler does not schedule the cpus in the correct order, the system can
waste a huge amount of time spinning until the next cpu can take the lock.

(See Thomas Friebel's talk "Prevent Guests from Spinning Around"
http://www.xen.org/files/xensummitboston08/LHP.pdf for more details.)

To address this, we add two hooks:
 - __ticket_spin_lock which is called after the cpu has been
   spinning on the lock for a significant number of iterations but has
   failed to take the lock (presumably because the cpu holding the lock
   has been descheduled).  The lock_spinning pvop is expected to block
   the cpu until it has been kicked by the current lock holder.
 - __ticket_spin_unlock, which on releasing a contended lock
   (there are more cpus with tail tickets), it looks to see if the next
   cpu is blocked and wakes it if so.

When compiled with CONFIG_PARAVIRT_SPINLOCKS disabled, a set of stub
functions causes all the extra code to go away.

Results:
=======
setup: 32 core machine with 32 vcpu KVM guest (HT off)  with 8GB RAM
base = 3.11-rc
patched = base + pvspinlock V12

+-----------------+----------------+--------+
 dbench (Throughput in MB/sec. Higher is better)
+-----------------+----------------+--------+
|   base (stdev %)|patched(stdev%) | %gain  |
+-----------------+----------------+--------+
| 15035.3   (0.3) |15150.0   (0.6) |   0.8  |
|  1470.0   (2.2) | 1713.7   (1.9) |  16.6  |
|   848.6   (4.3) |  967.8   (4.3) |  14.0  |
|   652.9   (3.5) |  685.3   (3.7) |   5.0  |
+-----------------+----------------+--------+

pvspinlock shows benefits for overcommit ratio > 1 for PLE enabled cases,
and undercommits results are flat

Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Link: http://lkml.kernel.org/r/1376058122-8248-2-git-send-email-raghavendra.kt@linux.vnet.ibm.com
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: Attilio Rao <attilio.rao@citrix.com>
[ Raghavendra: Changed SPIN_THRESHOLD, fixed redefinition of arch_spinlock_t]
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2013-08-09 07:53:05 -07:00
Paul Gortmaker
148f9bb877 x86: delete __cpuinit usage from all x86 files
The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications.  For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.

After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out.  Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.

Note that some harmless section mismatch warnings may result, since
notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
are flagged as __cpuinit  -- so if we remove the __cpuinit from
arch specific callers, we will also get section mismatch warnings.
As an intermediate step, we intend to turn the linux/init.h cpuinit
content into no-ops as early as possible, since that will get rid
of these warnings.  In any case, they are temporary and harmless.

This removes all the arch/x86 uses of the __cpuinit macros from
all C files.  x86 only had the one __CPUINIT used in assembly files,
and it wasn't paired off with a .previous or a __FINIT, so we can
delete it directly w/o any corresponding additional change there.

[1] https://lkml.org/lkml/2013/5/20/589

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2013-07-14 19:36:56 -04:00
Linus Torvalds
8cbd0eefca Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux
Pull thermal management updates from Zhang Rui:
 "There are not too many changes this time, except two new platform
  thermal drivers, ti-soc-thermal driver and x86_pkg_temp_thermal
  driver, and a couple of small fixes.

  Highlights:

   - move the ti-soc-thermal driver out of the staging tree to the
     thermal tree.

   - introduce the x86_pkg_temp_thermal driver.  This driver registers
     CPU digital temperature package level sensor as a thermal zone.

   - small fixes/cleanups including removing redundant use of
     platform_set_drvdata() and of_match_ptr for all platform thermal
     drivers"

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux: (34 commits)
  thermal: cpu_cooling: fix stub function
  thermal: ti-soc-thermal: use standard GPIO DT bindings
  thermal: MAINTAINERS: Add git tree path for SoC specific updates
  thermal: fix x86_pkg_temp_thermal.c build and Kconfig
  Thermal: Documentation for x86 package temperature thermal driver
  Thermal: CPU Package temperature thermal
  thermal: consider emul_temperature while computing trend
  thermal: ti-soc-thermal: add DT example for DRA752 chip
  thermal: ti-soc-thermal: add dra752 chip to device table
  thermal: ti-soc-thermal: add thermal data for DRA752 chips
  thermal: ti-soc-thermal: remove usage of IS_ERR_OR_NULL
  thermal: ti-soc-thermal: freeze FSM while computing trend
  thermal: ti-soc-thermal: remove external heat while extrapolating hotspot
  thermal: ti-soc-thermal: update DT reference for OMAP5430
  x86, mcheck, therm_throt: Process package thresholds
  thermal: cpu_cooling: fix 'descend' check in get_property()
  Thermal: spear: Remove redundant use of of_match_ptr
  Thermal: kirkwood: Remove redundant use of of_match_ptr
  Thermal: dove: Remove redundant use of of_match_ptr
  Thermal: armada: Remove redundant use of of_match_ptr
  ...
2013-07-11 12:26:08 -07:00
Linus Torvalds
2e17c5a97e Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux
Pull drm updates from Dave Airlie:
 "Okay this is the big one, I was stalled on the fbdev pull req as I
  stupidly let fbdev guys merge a patch I required to fix a warning with
  some patches I had, they ended up merging the patch from the wrong
  place, but the warning should be fixed.  In future I'll just take the
  patch myself!

  Outside drm:

  There are some snd changes for the HDMI audio interactions on haswell,
  they've been acked for inclusion via my tree.  This relies on the
  wound/wait tree from Ingo which is already merged.

  Major changes:

  AMD finally released the dynamic power management code for all their
  GPUs from r600->present day, this is great, off by default for now but
  also a huge amount of code, in fact it is most of this pull request.

  Since it landed there has been a lot of community testing and Alex has
  sent a lot of fixes for any bugs found so far.  I suspect radeon might
  now be the biggest kernel driver ever :-P p.s.  radeon.dpm=1 to enable
  dynamic powermanagement for anyone.

  New drivers:

  Renesas r-car display unit.

  Other highlights:

   - core: GEM CMA prime support, use new w/w mutexs for TTM
     reservations, cursor hotspot, doc updates
   - dvo chips: chrontel 7010B support
   - i915: Haswell (fbc, ips, vecs, watermarks, audio powerwell),
     Valleyview (enabled by default, rc6), lots of pll reworking, 30bpp
     support (this time for sure)
   - nouveau: async buffer object deletion, context/register init
     updates, kernel vp2 engine support, GF117 support, GK110 accel
     support (with external nvidia ucode), context cleanups.
   - exynos: memory leak fixes, Add S3C64XX SoC series support, device
     tree updates, common clock framework support,
   - qxl: cursor hotspot support, multi-monitor support, suspend/resume
     support
   - mgag200: hw cursor support, g200 mode limiting
   - shmobile: prime support
   - tegra: fixes mostly

  I've been banging on this quite a lot due to the size of it, and it
  seems to okay on everything I've tested it on."

* 'drm-next' of git://people.freedesktop.org/~airlied/linux: (811 commits)
  drm/radeon/dpm: implement vblank_too_short callback for si
  drm/radeon/dpm: implement vblank_too_short callback for cayman
  drm/radeon/dpm: implement vblank_too_short callback for btc
  drm/radeon/dpm: implement vblank_too_short callback for evergreen
  drm/radeon/dpm: implement vblank_too_short callback for 7xx
  drm/radeon/dpm: add checks against vblank time
  drm/radeon/dpm: add helper to calculate vblank time
  drm/radeon: remove stray line in old pm code
  drm/radeon/dpm: fix display_gap programming on rv7xx
  drm/nvc0/gr: fix gpc firmware regression
  drm/nouveau: fix minor thinko causing bo moves to not be async on kepler
  drm/radeon/dpm: implement force performance level for TN
  drm/radeon/dpm: implement force performance level for ON/LN
  drm/radeon/dpm: implement force performance level for SI
  drm/radeon/dpm: implement force performance level for cayman
  drm/radeon/dpm: implement force performance levels for 7xx/eg/btc
  drm/radeon/dpm: add infrastructure to force performance levels
  drm/radeon: fix surface setup on r1xx
  drm/radeon: add support for 3d perf states on older asics
  drm/radeon: set default clocks for SI when DPM is disabled
  ...
2013-07-09 16:04:31 -07:00
Robin Holt
1b3a5d02ee reboot: move arch/x86 reboot= handling to generic kernel
Merge together the unicore32, arm, and x86 reboot= command line
parameter handling.

Signed-off-by: Robin Holt <holt@sgi.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Russ Anderson <rja@sgi.com>
Cc: Robin Holt <holt@sgi.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-09 10:33:29 -07:00
Linus Torvalds
21884a83b2 Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer core updates from Thomas Gleixner:
 "The timer changes contain:

   - posix timer code consolidation and fixes for odd corner cases

   - sched_clock implementation moved from ARM to core code to avoid
     duplication by other architectures

   - alarm timer updates

   - clocksource and clockevents unregistration facilities

   - clocksource/events support for new hardware

   - precise nanoseconds RTC readout (Xen feature)

   - generic support for Xen suspend/resume oddities

   - the usual lot of fixes and cleanups all over the place

  The parts which touch other areas (ARM/XEN) have been coordinated with
  the relevant maintainers.  Though this results in an handful of
  trivial to solve merge conflicts, which we preferred over nasty cross
  tree merge dependencies.

  The patches which have been committed in the last few days are bug
  fixes plus the posix timer lot.  The latter was in akpms queue and
  next for quite some time; they just got forgotten and Frederic
  collected them last minute."

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (59 commits)
  hrtimer: Remove unused variable
  hrtimers: Move SMP function call to thread context
  clocksource: Reselect clocksource when watchdog validated high-res capability
  posix-cpu-timers: don't account cpu timer after stopped thread runtime accounting
  posix_timers: fix racy timer delta caching on task exit
  posix-timers: correctly get dying task time sample in posix_cpu_timer_schedule()
  selftests: add basic posix timers selftests
  posix_cpu_timers: consolidate expired timers check
  posix_cpu_timers: consolidate timer list cleanups
  posix_cpu_timer: consolidate expiry time type
  tick: Sanitize broadcast control logic
  tick: Prevent uncontrolled switch to oneshot mode
  tick: Make oneshot broadcast robust vs. CPU offlining
  x86: xen: Sync the CMOS RTC as well as the Xen wallclock
  x86: xen: Sync the wallclock when the system time is set
  timekeeping: Indicate that clock was set in the pvclock gtod notifier
  timekeeping: Pass flags instead of multiple bools to timekeeping_update()
  xen: Remove clock_was_set() call in the resume path
  hrtimers: Support resuming with two or more CPUs online (but stopped)
  timer: Fix jiffies wrap behavior of round_jiffies_common()
  ...
2013-07-06 14:09:38 -07:00
Linus Torvalds
b2c311075d Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
Pull crypto update from Herbert Xu:
 - Do not idle omap device between crypto operations in one session.
 - Added sha224/sha384 shims for SSSE3.
 - More optimisations for camellia-aesni-avx2.
 - Removed defunct blowfish/twofish AVX2 implementations.
 - Added unaligned buffer self-tests.
 - Added PCLMULQDQ optimisation for CRCT10DIF.
 - Added support for Freescale's DCP co-processor
 - Misc fixes.

* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (44 commits)
  crypto: testmgr - test hash implementations with unaligned buffers
  crypto: testmgr - test AEADs with unaligned buffers
  crypto: testmgr - test skciphers with unaligned buffers
  crypto: testmgr - check that entries in alg_test_descs are in correct order
  Revert "crypto: twofish - add AVX2/x86_64 assembler implementation of twofish cipher"
  Revert "crypto: blowfish - add AVX2/x86_64 implementation of blowfish cipher"
  crypto: camellia-aesni-avx2 - tune assembly code for more performance
  hwrng: bcm2835 - fix MODULE_LICENSE tag
  hwrng: nomadik - use clk_prepare_enable()
  crypto: picoxcell - replace strict_strtoul() with kstrtoul()
  crypto: dcp - Staticize local symbols
  crypto: dcp - Use NULL instead of 0
  crypto: dcp - Use devm_* APIs
  crypto: dcp - Remove redundant platform_set_drvdata()
  hwrng: use platform_{get,set}_drvdata()
  crypto: omap-aes - Don't idle/start AES device between Encrypt operations
  crypto: crct10dif - Use PTR_RET
  crypto: ux500 - Cocci spatch "resource_size.spatch"
  crypto: sha256_ssse3 - add sha224 support
  crypto: sha512_ssse3 - add sha384 support
  ...
2013-07-05 12:12:33 -07:00
Thomas Gleixner
2b0f89317e Merge branch 'timers/posix-cpu-timers-for-tglx' of
git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks into timers/core

Frederic sayed: "Most of these patches have been hanging around for
several month now, in -mmotm for a significant chunk. They already
missed a few releases."

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-07-04 23:11:22 +02:00
Linus Torvalds
7f0ef0267e Merge branch 'akpm' (updates from Andrew Morton)
Merge first patch-bomb from Andrew Morton:
 - various misc bits
 - I'm been patchmonkeying ocfs2 for a while, as Joel and Mark have been
   distracted.  There has been quite a bit of activity.
 - About half the MM queue
 - Some backlight bits
 - Various lib/ updates
 - checkpatch updates
 - zillions more little rtc patches
 - ptrace
 - signals
 - exec
 - procfs
 - rapidio
 - nbd
 - aoe
 - pps
 - memstick
 - tools/testing/selftests updates

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (445 commits)
  tools/testing/selftests: don't assume the x bit is set on scripts
  selftests: add .gitignore for kcmp
  selftests: fix clean target in kcmp Makefile
  selftests: add .gitignore for vm
  selftests: add hugetlbfstest
  self-test: fix make clean
  selftests: exit 1 on failure
  kernel/resource.c: remove the unneeded assignment in function __find_resource
  aio: fix wrong comment in aio_complete()
  drivers/w1/slaves/w1_ds2408.c: add magic sequence to disable P0 test mode
  drivers/memstick/host/r592.c: convert to module_pci_driver
  drivers/memstick/host/jmb38x_ms: convert to module_pci_driver
  pps-gpio: add device-tree binding and support
  drivers/pps/clients/pps-gpio.c: convert to module_platform_driver
  drivers/pps/clients/pps-gpio.c: convert to devm_* helpers
  drivers/parport/share.c: use kzalloc
  Documentation/accounting/getdelays.c: avoid strncpy in accounting tool
  aoe: update internal version number to v83
  aoe: update copyright date
  aoe: perform I/O completions in parallel
  ...
2013-07-03 17:12:13 -07:00
Oleg Nesterov
37f0765552 x86: kill TIF_DEBUG
Because it is not used.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jan Kratochvil <jan.kratochvil@redhat.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-03 16:08:01 -07:00
Pavel Emelyanov
0f8975ec4d mm: soft-dirty bits for user memory changes tracking
The soft-dirty is a bit on a PTE which helps to track which pages a task
writes to.  In order to do this tracking one should

  1. Clear soft-dirty bits from PTEs ("echo 4 > /proc/PID/clear_refs)
  2. Wait some time.
  3. Read soft-dirty bits (55'th in /proc/PID/pagemap2 entries)

To do this tracking, the writable bit is cleared from PTEs when the
soft-dirty bit is.  Thus, after this, when the task tries to modify a
page at some virtual address the #PF occurs and the kernel sets the
soft-dirty bit on the respective PTE.

Note, that although all the task's address space is marked as r/o after
the soft-dirty bits clear, the #PF-s that occur after that are processed
fast.  This is so, since the pages are still mapped to physical memory,
and thus all the kernel does is finds this fact out and puts back
writable, dirty and soft-dirty bits on the PTE.

Another thing to note, is that when mremap moves PTEs they are marked
with soft-dirty as well, since from the user perspective mremap modifies
the virtual memory at mremap's new address.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-03 16:07:26 -07:00
Linus Torvalds
f991fae5c6 Power management and ACPI updates for 3.11-rc1
- Hotplug changes allowing device hot-removal operations to fail
   gracefully (instead of crashing the kernel) if they cannot be
   carried out completely.  From Rafael J Wysocki and Toshi Kani.
 
 - Freezer update from Colin Cross and Mandeep Singh Baines targeted
   at making the freezing of tasks a bit less heavy weight operation.
 
 - cpufreq resume fix from Srivatsa S Bhat for a regression introduced
   during the 3.10 cycle causing some cpufreq sysfs attributes to
   return wrong values to user space after resume.
 
 - New freqdomain_cpus sysfs attribute for the acpi-cpufreq driver to
   provide information previously available via related_cpus from
   Lan Tianyu.
 
 - cpufreq fixes and cleanups from Viresh Kumar, Jacob Shin,
   Heiko Stübner, Xiaoguang Chen, Ezequiel Garcia, Arnd Bergmann, and
   Tang Yuantian.
 
 - Fix for an ACPICA regression causing suspend/resume issues to
   appear on some systems introduced during the 3.4 development cycle
   from Lv Zheng.
 
 - ACPICA fixes and cleanups from Bob Moore, Tomasz Nowicki, Lv Zheng,
   Chao Guan, and Zhang Rui.
 
 - New cupidle driver for Xilinx Zynq processors from Michal Simek.
 
 - cpuidle fixes and cleanups from Daniel Lezcano.
 
 - Changes to make suspend/resume work correctly in Xen guests from
   Konrad Rzeszutek Wilk.
 
 - ACPI device power management fixes and cleanups from Fengguang Wu
   and Rafael J Wysocki.
 
 - ACPI documentation updates from Lv Zheng, Aaron Lu and Hanjun Guo.
 
 - Fix for the IA-64 issue that was the reason for reverting commit
   9f29ab1 and updates of the ACPI scan code from Rafael J Wysocki.
 
 - Mechanism for adding CMOS RTC address space handlers from Lan Tianyu
   (to allow some EC-related breakage to be fixed on some systems).
 
 - Spec-compliant implementation of acpi_os_get_timer() from
   Mika Westerberg.
 
 - Modification of do_acpi_find_child() to execute _STA in order to
   to avoid situations in which a pointer to a disabled device object
   is returned instead of an enabled one with the same _ADR value.
   From Jeff Wu.
 
 - Intel BayTrail PCH (Platform Controller Hub) support for the ACPI
   Intel Low-Power Subsystems (LPSS) driver and modificaions of that
   driver to work around a couple of known BIOS issues from
   Mika Westerberg and Heikki Krogerus.
 
 - EC driver fix from Vasiliy Kulikov to make it use get_user() and
   put_user() instead of dereferencing user space pointers blindly.
 
 - Assorted ACPI code cleanups from Bjorn Helgaas, Nicholas Mazzuca and
   Toshi Kani.
 
 - Modification of the "runtime idle" helper routine to take the return
   values of the callbacks executed by it into account and to call
   rpm_suspend() if they return 0, which allows some code bloat
   reduction to be done, from Rafael J Wysocki and Alan Stern.
 
 - New trace points for PM QoS from Sahara <keun-o.park@windriver.com>.
 
 - PM QoS documentation update from Lan Tianyu.
 
 - Assorted core PM code cleanups and changes from Bernie Thompson,
   Bjorn Helgaas, Julius Werner, and Shuah Khan.
 
 - New devfreq driver for the Exynos5-bus device from Abhilash Kesavan.
 
 - Minor devfreq cleanups, fixes and MAINTAINERS update from
   MyungJoo Ham, Abhilash Kesavan, Paul Bolle, Rajagopal Venkat, and
   Wei Yongjun.
 
 - OMAP Adaptive Voltage Scaling (AVS) SmartReflex voltage control
   driver updates from Andrii Tseglytskyi and Nishanth Menon.
 
 /
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Merge tag 'pm+acpi-3.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management and ACPI updates from Rafael Wysocki:
 "This time the total number of ACPI commits is slightly greater than
  the number of cpufreq commits, but Viresh Kumar (who works on cpufreq)
  remains the most active patch submitter.

  To me, the most significant change is the addition of offline/online
  device operations to the driver core (with the Greg's blessing) and
  the related modifications of the ACPI core hotplug code.  Next are the
  freezer updates from Colin Cross that should make the freezing of
  tasks a bit less heavy weight.

  We also have a couple of regression fixes, a number of fixes for
  issues that have not been identified as regressions, two new drivers
  and a bunch of cleanups all over.

  Highlights:

   - Hotplug changes to support graceful hot-removal failures.

     It sometimes is necessary to fail device hot-removal operations
     gracefully if they cannot be carried out completely.  For example,
     if memory from a memory module being hot-removed has been allocated
     for the kernel's own use and cannot be moved elsewhere, it's
     desirable to fail the hot-removal operation in a graceful way
     rather than to crash the kernel, but currenty a success or a kernel
     crash are the only possible outcomes of an attempted memory
     hot-removal.  Needless to say, that is not a very attractive
     alternative and it had to be addressed.

     However, in order to make it work for memory, I first had to make
     it work for CPUs and for this purpose I needed to modify the ACPI
     processor driver.  It's been split into two parts, a resident one
     handling the low-level initialization/cleanup and a modular one
     playing the actual driver's role (but it binds to the CPU system
     device objects rather than to the ACPI device objects representing
     processors).  That's been sort of like a live brain surgery on a
     patient who's riding a bike.

     So this is a little scary, but since we found and fixed a couple of
     regressions it caused to happen during the early linux-next testing
     (a month ago), nobody has complained.

     As a bonus we remove some duplicated ACPI hotplug code, because the
     ACPI-based CPU hotplug is now going to use the common ACPI hotplug
     code.

   - Lighter weight freezing of tasks.

     These changes from Colin Cross and Mandeep Singh Baines are
     targeted at making the freezing of tasks a bit less heavy weight
     operation.  They reduce the number of tasks woken up every time
     during the freezing, by using the observation that the freezer
     simply doesn't need to wake up some of them and wait for them all
     to call refrigerator().  The time needed for the freezer to decide
     to report a failure is reduced too.

     Also reintroduced is the check causing a lockdep warining to
     trigger when try_to_freeze() is called with locks held (which is
     generally unsafe and shouldn't happen).

   - cpufreq updates

     First off, a commit from Srivatsa S Bhat fixes a resume regression
     introduced during the 3.10 cycle causing some cpufreq sysfs
     attributes to return wrong values to user space after resume.  The
     fix is kind of fresh, but also it's pretty obvious once Srivatsa
     has identified the root cause.

     Second, we have a new freqdomain_cpus sysfs attribute for the
     acpi-cpufreq driver to provide information previously available via
     related_cpus.  From Lan Tianyu.

     Finally, we fix a number of issues, mostly related to the
     CPUFREQ_POSTCHANGE notifier and cpufreq Kconfig options and clean
     up some code.  The majority of changes from Viresh Kumar with bits
     from Jacob Shin, Heiko Stübner, Xiaoguang Chen, Ezequiel Garcia,
     Arnd Bergmann, and Tang Yuantian.

   - ACPICA update

     A usual bunch of updates from the ACPICA upstream.

     During the 3.4 cycle we introduced support for ACPI 5 extended
     sleep registers, but they are only supposed to be used if the
     HW-reduced mode bit is set in the FADT flags and the code attempted
     to use them without checking that bit.  That caused suspend/resume
     regressions to happen on some systems.  Fix from Lv Zheng causes
     those registers to be used only if the HW-reduced mode bit is set.

     Apart from this some other ACPICA bugs are fixed and code cleanups
     are made by Bob Moore, Tomasz Nowicki, Lv Zheng, Chao Guan, and
     Zhang Rui.

   - cpuidle updates

     New driver for Xilinx Zynq processors is added by Michal Simek.

     Multidriver support simplification, addition of some missing
     kerneldoc comments and Kconfig-related fixes come from Daniel
     Lezcano.

   - ACPI power management updates

     Changes to make suspend/resume work correctly in Xen guests from
     Konrad Rzeszutek Wilk, sparse warning fix from Fengguang Wu and
     cleanups and fixes of the ACPI device power state selection
     routine.

   - ACPI documentation updates

     Some previously missing pieces of ACPI documentation are added by
     Lv Zheng and Aaron Lu (hopefully, that will help people to
     uderstand how the ACPI subsystem works) and one outdated doc is
     updated by Hanjun Guo.

   - Assorted ACPI updates

     We finally nailed down the IA-64 issue that was the reason for
     reverting commit 9f29ab11dd ("ACPI / scan: do not match drivers
     against objects having scan handlers"), so we can fix it and move
     the ACPI scan handler check added to the ACPI video driver back to
     the core.

     A mechanism for adding CMOS RTC address space handlers is
     introduced by Lan Tianyu to allow some EC-related breakage to be
     fixed on some systems.

     A spec-compliant implementation of acpi_os_get_timer() is added by
     Mika Westerberg.

     The evaluation of _STA is added to do_acpi_find_child() to avoid
     situations in which a pointer to a disabled device object is
     returned instead of an enabled one with the same _ADR value.  From
     Jeff Wu.

     Intel BayTrail PCH (Platform Controller Hub) support is added to
     the ACPI driver for Intel Low-Power Subsystems (LPSS) and that
     driver is modified to work around a couple of known BIOS issues.
     Changes from Mika Westerberg and Heikki Krogerus.

     The EC driver is fixed by Vasiliy Kulikov to use get_user() and
     put_user() instead of dereferencing user space pointers blindly.

     Code cleanups are made by Bjorn Helgaas, Nicholas Mazzuca and Toshi
     Kani.

   - Assorted power management updates

     The "runtime idle" helper routine is changed to take the return
     values of the callbacks executed by it into account and to call
     rpm_suspend() if they return 0, which allows us to reduce the
     overall code bloat a bit (by dropping some code that's not
     necessary any more after that modification).

     The runtime PM documentation is updated by Alan Stern (to reflect
     the "runtime idle" behavior change).

     New trace points for PM QoS are added by Sahara
     (<keun-o.park@windriver.com>).

     PM QoS documentation is updated by Lan Tianyu.

     Code cleanups are made and minor issues are addressed by Bernie
     Thompson, Bjorn Helgaas, Julius Werner, and Shuah Khan.

   - devfreq updates

     New driver for the Exynos5-bus device from Abhilash Kesavan.

     Minor cleanups, fixes and MAINTAINERS update from MyungJoo Ham,
     Abhilash Kesavan, Paul Bolle, Rajagopal Venkat, and Wei Yongjun.

   - OMAP power management updates

     Adaptive Voltage Scaling (AVS) SmartReflex voltage control driver
     updates from Andrii Tseglytskyi and Nishanth Menon."

* tag 'pm+acpi-3.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (162 commits)
  cpufreq: Fix cpufreq regression after suspend/resume
  ACPI / PM: Fix possible NULL pointer deref in acpi_pm_device_sleep_state()
  PM / Sleep: Warn about system time after resume with pm_trace
  cpufreq: don't leave stale policy pointer in cdbs->cur_policy
  acpi-cpufreq: Add new sysfs attribute freqdomain_cpus
  cpufreq: make sure frequency transitions are serialized
  ACPI: implement acpi_os_get_timer() according the spec
  ACPI / EC: Add HP Folio 13 to ec_dmi_table in order to skip DSDT scan
  ACPI: Add CMOS RTC Operation Region handler support
  ACPI / processor: Drop unused variable from processor_perflib.c
  cpufreq: tegra: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: s3c64xx: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: omap: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: imx6q: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: exynos: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: dbx500: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: davinci: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: arm-big-little: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: powernow-k8: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: pcc: call CPUFREQ_POSTCHANGE notfier in error cases
  ...
2013-07-03 14:35:40 -07:00
Linus Torvalds
fe489bf450 KVM fixes for 3.11
On the x86 side, there are some optimizations and documentation updates.
 The big ARM/KVM change for 3.11, support for AArch64, will come through
 Catalin Marinas's tree.  s390 and PPC have misc cleanups and bugfixes.
 
 There is a conflict due to "s390/pgtable: fix ipte notify bit" having
 entered 3.10 through Martin Schwidefsky's s390 tree.  This pull request
 has additional changes on top, so this tree's version is the correct one.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM fixes from Paolo Bonzini:
 "On the x86 side, there are some optimizations and documentation
  updates.  The big ARM/KVM change for 3.11, support for AArch64, will
  come through Catalin Marinas's tree.  s390 and PPC have misc cleanups
  and bugfixes"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (87 commits)
  KVM: PPC: Ignore PIR writes
  KVM: PPC: Book3S PR: Invalidate SLB entries properly
  KVM: PPC: Book3S PR: Allow guest to use 1TB segments
  KVM: PPC: Book3S PR: Don't keep scanning HPTEG after we find a match
  KVM: PPC: Book3S PR: Fix invalidation of SLB entry 0 on guest entry
  KVM: PPC: Book3S PR: Fix proto-VSID calculations
  KVM: PPC: Guard doorbell exception with CONFIG_PPC_DOORBELL
  KVM: Fix RTC interrupt coalescing tracking
  kvm: Add a tracepoint write_tsc_offset
  KVM: MMU: Inform users of mmio generation wraparound
  KVM: MMU: document fast invalidate all mmio sptes
  KVM: MMU: document fast invalidate all pages
  KVM: MMU: document fast page fault
  KVM: MMU: document mmio page fault
  KVM: MMU: document write_flooding_count
  KVM: MMU: document clear_spte_count
  KVM: MMU: drop kvm_mmu_zap_mmio_sptes
  KVM: MMU: init kvm generation close to mmio wrap-around value
  KVM: MMU: add tracepoint for check_mmio_spte
  KVM: MMU: fast invalidate all mmio sptes
  ...
2013-07-03 13:21:40 -07:00
Linus Torvalds
96a3d998fb Merge branch 'x86-tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 tracing updates from Ingo Molnar:
 "This tree adds IRQ vector tracepoints that are named after the handler
  and which output the vector #, based on a zero-overhead approach that
  relies on changing the IDT entries, by Seiji Aguchi.

  The new tracepoints look like this:

   # perf list | grep -i irq_vector
    irq_vectors:local_timer_entry                      [Tracepoint event]
    irq_vectors:local_timer_exit                       [Tracepoint event]
    irq_vectors:reschedule_entry                       [Tracepoint event]
    irq_vectors:reschedule_exit                        [Tracepoint event]
    irq_vectors:spurious_apic_entry                    [Tracepoint event]
    irq_vectors:spurious_apic_exit                     [Tracepoint event]
    irq_vectors:error_apic_entry                       [Tracepoint event]
    irq_vectors:error_apic_exit                        [Tracepoint event]
   [...]"

* 'x86-tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/tracing: Add config option checking to the definitions of mce handlers
  trace,x86: Do not call local_irq_save() in load_current_idt()
  trace,x86: Move creation of irq tracepoints from apic.c to irq.c
  x86, trace: Add irq vector tracepoints
  x86: Rename variables for debugging
  x86, trace: Introduce entering/exiting_irq()
  tracing: Add DEFINE_EVENT_FN() macro
2013-07-02 16:31:49 -07:00
Linus Torvalds
3045f94a20 Merge branch 'x86-ras-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 RAS update from Ingo Molnar:
 "The changes in this tree are:

   - ACPI APEI (ACPI Platform Error Interface) improvements, by Chen
     Gong
   - misc MCE fixes/cleanups"

* 'x86-ras-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mce: Update MCE severity condition check
  mce: acpi/apei: Add comments to clarify usage of the various bitfields in the MCA subsystem
  ACPI/APEI: Update einj documentation for param1/param2
  ACPI/APEI: Add parameter check before error injection
  ACPI, APEI, EINJ: Fix error return code in einj_init()
  x86, mce: Fix "braodcast" typo
2013-07-02 16:30:46 -07:00
Linus Torvalds
1982269a5c Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 mm changes from Ingo Molnar:
 "Misc improvements:

   - Fix /proc/mtrr reporting
   - Fix ioremap printout
   - Remove the unused pvclock fixmap entry on 32-bit
   - misc cleanups"

* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/ioremap: Correct function name output
  x86: Fix /proc/mtrr with base/size more than 44bits
  ix86: Don't waste fixmap entries
  x86/mm: Drop unneeded include <asm/*pgtable, page*_types.h>
  x86_64: Correct phys_addr in cleanup_highmap comment
2013-07-02 16:29:05 -07:00
Linus Torvalds
fdd78889aa Merge branch 'x86-microcode-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 microcode loading update from Ingo Molnar:
 "Two main changes that improve microcode loading on AMD CPUs:

   - Add support for all-in-one binary microcode files that concatenate
     the microcode images of multiple processor families, by Jacob Shin

   - Add early microcode loading (embedded in the initrd) support, also
     by Jacob Shin"

* 'x86-microcode-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, microcode, amd: Another early loading fixup
  x86, microcode, amd: Allow multiple families' bin files appended together
  x86, microcode, amd: Make find_ucode_in_initrd() __init
  x86, microcode, amd: Fix warnings and errors on with CONFIG_MICROCODE=m
  x86, microcode, amd: Early microcode patch loading support for AMD
  x86, microcode, amd: Refactor functions to prepare for early loading
  x86, microcode: Vendor abstract out save_microcode_in_initrd()
  x86, microcode, intel: Correct typo in printk
2013-07-02 16:28:10 -07:00
Linus Torvalds
d652df0b2f Merge branch 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 FPU changes from Ingo Molnar:
 "There are two bigger changes in this tree:

   - Add an [early-use-]safe static_cpu_has() variant and other
     robustness improvements, including the new X86_DEBUG_STATIC_CPU_HAS
     configurable debugging facility, motivated by recent obscure FPU
     code bugs, by Borislav Petkov

   - Reimplement FPU detection code in C and drop the old asm code, by
     Peter Anvin."

* 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, fpu: Use static_cpu_has_safe before alternatives
  x86: Add a static_cpu_has_safe variant
  x86: Sanity-check static_cpu_has usage
  x86, cpu: Add a synthetic, always true, cpu feature
  x86: Get rid of ->hard_math and all the FPU asm fu
2013-07-02 16:26:44 -07:00
Linus Torvalds
4d6f843a38 Merge branch 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 EFI changes from Ingo Molnar:
 "Two fixes that should in principle increase robustness of our
  interaction with the EFI firmware, and a cleanup"

* 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, efi: retry ExitBootServices() on failure
  efi: Convert runtime services function ptrs
  UEFI: Don't pass boot services regions to SetVirtualAddressMap()
2013-07-02 16:25:50 -07:00
Linus Torvalds
35c23d5d79 Merge branch 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cpu updates from Ingo Molnar:
 "Two changes:

   - Extend 32-bit double fault debugging aid to 64-bit
   - Fix a build warning"

* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/intel/cacheinfo: Shut up last long-standing warning
  x86: Extend #DF debugging aid to 64-bit
2013-07-02 16:24:24 -07:00
Linus Torvalds
57935b262c Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cleanups from Ingo Molnar:
 "Misc x86 cleanups"

* 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, reloc: Use xorl instead of xorq in relocate_kernel_64.S
  x86, cleanups: Remove extra tab in __flush_tlb_one()
  x86/mce: Remove check for CONFIG_X86_MCE_P4THERMAL
2013-07-02 16:23:50 -07:00
Linus Torvalds
002e44bfb5 Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull asm/x86 changes from Ingo Molnar:
 "Misc changes, with a bigger processor-flags cleanup/reorganization by
  Peter Anvin"

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, asm, cleanup: Replace open-coded control register values with symbolic
  x86, processor-flags: Fix the datatypes and add bit number defines
  x86: Rename X86_CR4_RDWRGSFS to X86_CR4_FSGSBASE
  x86, flags: Rename X86_EFLAGS_BIT1 to X86_EFLAGS_FIXED
  linux/const.h: Add _BITUL() and _BITULL()
  x86/vdso: Convert use of typedef ctl_table to struct ctl_table
  x86: __force_order doesn't need to be an actual variable
2013-07-02 16:21:45 -07:00
Linus Torvalds
e13053f506 Merge branch 'sched-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull voluntary preemption fixes from Ingo Molnar:
 "This tree contains a speedup which is achieved through better
  might_sleep()/might_fault() preemption point annotations for uaccess
  functions, by Michael S Tsirkin:

  1. The only reason uaccess routines might sleep is if they fault.
     Make this explicit for all architectures.

  2. A voluntary preemption point in uaccess functions means compiler
     can't inline them efficiently, this breaks assumptions that they
     are very fast and small that e.g.  net code seems to make.  Remove
     this preemption point so behaviour matches with what callers
     assume.

  3. Accesses (e.g through socket ops) to kernel memory with KERNEL_DS
     like net/sunrpc does will never sleep.  Remove an unconditinal
     might_sleep() in the might_fault() inline in kernel.h (used when
     PROVE_LOCKING is not set).

  4. Accesses with pagefault_disable() return EFAULT but won't cause
     caller to sleep.  Check for that and thus avoid might_sleep() when
     PROVE_LOCKING is set.

  These changes offer a nice speedup for CONFIG_PREEMPT_VOLUNTARY=y
  kernels, here's a network bandwidth measurement between a virtual
  machine and the host:

   before:
        incoming: 7122.77   Mb/s
        outgoing: 8480.37   Mb/s

   after:
        incoming: 8619.24   Mb/s   [ +21.0% ]
        outgoing: 9455.42   Mb/s   [ +11.5% ]

  I kept these changes in a separate tree, separate from scheduler
  changes, because it's a mixed MM and scheduler topic"

* 'sched-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  mm, sched: Allow uaccess in atomic with pagefault_disable()
  mm, sched: Drop voluntary schedule from might_fault()
  x86: uaccess s/might_sleep/might_fault/
  tile: uaccess s/might_sleep/might_fault/
  powerpc: uaccess s/might_sleep/might_fault/
  mn10300: uaccess s/might_sleep/might_fault/
  microblaze: uaccess s/might_sleep/might_fault/
  m32r: uaccess s/might_sleep/might_fault/
  frv: uaccess s/might_sleep/might_fault/
  arm64: uaccess s/might_sleep/might_fault/
  asm-generic: uaccess s/might_sleep/might_fault/
2013-07-02 16:19:24 -07:00
Linus Torvalds
f0bb4c0ab0 Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf updates from Ingo Molnar:
 "Kernel improvements:

   - watchdog driver improvements by Li Zefan
   - Power7 CPI stack events related improvements by Sukadev Bhattiprolu
   - event multiplexing via hrtimers and other improvements by Stephane
     Eranian
   - kernel stack use optimization by Andrew Hunter
   - AMD IOMMU uncore PMU support by Suravee Suthikulpanit
   - NMI handling rate-limits by Dave Hansen
   - various hw_breakpoint fixes by Oleg Nesterov
   - hw_breakpoint overflow period sampling and related signal handling
     fixes by Jiri Olsa
   - Intel Haswell PMU support by Andi Kleen

  Tooling improvements:

   - Reset SIGTERM handler in workload child process, fix from David
     Ahern.
   - Makefile reorganization, prep work for Kconfig patches, from Jiri
     Olsa.
   - Add automated make test suite, from Jiri Olsa.
   - Add --percent-limit option to 'top' and 'report', from Namhyung
     Kim.
   - Sorting improvements, from Namhyung Kim.
   - Expand definition of sysfs format attribute, from Michael Ellerman.

  Tooling fixes:

   - 'perf tests' fixes from Jiri Olsa.
   - Make Power7 CPI stack events available in sysfs, from Sukadev
     Bhattiprolu.
   - Handle death by SIGTERM in 'perf record', fix from David Ahern.
   - Fix printing of perf_event_paranoid message, from David Ahern.
   - Handle realloc failures in 'perf kvm', from David Ahern.
   - Fix divide by 0 in variance, from David Ahern.
   - Save parent pid in thread struct, from David Ahern.
   - Handle JITed code in shared memory, from Andi Kleen.
   - Fixes for 'perf diff', from Jiri Olsa.
   - Remove some unused struct members, from Jiri Olsa.
   - Add missing liblk.a dependency for python/perf.so, fix from Jiri
     Olsa.
   - Respect CROSS_COMPILE in liblk.a, from Rabin Vincent.
   - No need to do locking when adding hists in perf report, only 'top'
     needs that, from Namhyung Kim.
   - Fix alignment of symbol column in in the hists browser (top,
     report) when -v is given, from NAmhyung Kim.
   - Fix 'perf top' -E option behavior, from Namhyung Kim.
   - Fix bug in isupper() and islower(), from Sukadev Bhattiprolu.
   - Fix compile errors in bp_signal 'perf test', from Sukadev
     Bhattiprolu.

  ... and more things"

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (102 commits)
  perf/x86: Disable PEBS-LL in intel_pmu_pebs_disable()
  perf/x86: Fix shared register mutual exclusion enforcement
  perf/x86/intel: Support full width counting
  x86: Add NMI duration tracepoints
  perf: Drop sample rate when sampling is too slow
  x86: Warn when NMI handlers take large amounts of time
  hw_breakpoint: Introduce "struct bp_cpuinfo"
  hw_breakpoint: Simplify *register_wide_hw_breakpoint()
  hw_breakpoint: Introduce cpumask_of_bp()
  hw_breakpoint: Simplify the "weight" usage in toggle_bp_slot() paths
  hw_breakpoint: Simplify list/idx mess in toggle_bp_slot() paths
  perf/x86/intel: Add mem-loads/stores support for Haswell
  perf/x86/intel: Support Haswell/v4 LBR format
  perf/x86/intel: Move NMI clearing to end of PMI handler
  perf/x86/intel: Add Haswell PEBS support
  perf/x86/intel: Add simple Haswell PMU support
  perf/x86/intel: Add Haswell PEBS record support
  perf/x86/intel: Fix sparse warning
  perf/x86/amd: AMD IOMMU Performance Counter PERF uncore PMU implementation
  perf/x86/amd: Add IOMMU Performance Counter resource management
  ...
2013-07-02 16:15:23 -07:00
Linus Torvalds
0c46d68d19 Merge branch 'core-mutexes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull WW mutex support from Ingo Molnar:
 "This tree adds support for wound/wait style locks, which the graphics
  guys would like to make use of in the TTM graphics subsystem.

  Wound/wait mutexes are used when other multiple lock acquisitions of a
  similar type can be done in an arbitrary order.  The deadlock handling
  used here is called wait/wound in the RDBMS literature: The older
  tasks waits until it can acquire the contended lock.  The younger
  tasks needs to back off and drop all the locks it is currently
  holding, ie the younger task is wounded.

  See this LWN.net description of W/W mutexes:

     https://lwn.net/Articles/548909/

  The comments there outline specific usecases for this facility (which
  have already been implemented for the DRM tree).

  Also see Documentation/ww-mutex-design.txt for more details"

* 'core-mutexes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking-selftests: Handle unexpected failures more strictly
  mutex: Add more w/w tests to test EDEADLK path handling
  mutex: Add more tests to lib/locking-selftest.c
  mutex: Add w/w tests to lib/locking-selftest.c
  mutex: Add w/w mutex slowpath debugging
  mutex: Add support for wound/wait style locks
  arch: Make __mutex_fastpath_lock_retval return whether fastpath succeeded or not
2013-07-02 16:09:13 -07:00
Linus Torvalds
63580e51bb Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull VFS patches (part 1) from Al Viro:
 "The major change in this pile is ->readdir() replacement with
  ->iterate(), dealing with ->f_pos races in ->readdir() instances for
  good.

  There's a lot more, but I'd prefer to split the pull request into
  several stages and this is the first obvious cutoff point."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (67 commits)
  [readdir] constify ->actor
  [readdir] ->readdir() is gone
  [readdir] convert ecryptfs
  [readdir] convert coda
  [readdir] convert ocfs2
  [readdir] convert fatfs
  [readdir] convert xfs
  [readdir] convert btrfs
  [readdir] convert hostfs
  [readdir] convert afs
  [readdir] convert ncpfs
  [readdir] convert hfsplus
  [readdir] convert hfs
  [readdir] convert befs
  [readdir] convert cifs
  [readdir] convert freevxfs
  [readdir] convert fuse
  [readdir] convert hpfs
  reiserfs: switch reiserfs_readdir_dentry to inode
  reiserfs: is_privroot_deh() needs only directory inode, actually
  ...
2013-07-02 09:28:37 -07:00
Al Viro
40d158e618 consolidate io_remap_pfn_range definitions
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-06-29 12:46:35 +04:00
Rafael J. Wysocki
3b4550e0e0 Merge branch 'acpi-pm'
* acpi-pm:
  ACPI / PM: Rework and clean up acpi_dev_pm_get_state()
  ACPI / PM: Replace ACPI_STATE_D3 with ACPI_STATE_D3_COLD in device_pm.c
  ACPI / PM: Rename function acpi_device_power_state() and make it static
  ACPI / PM: acpi_processor_suspend() can be static
  xen / ACPI / sleep: Register an acpi_suspend_lowlevel callback.
  x86 / ACPI / sleep: Provide registration for acpi_suspend_lowlevel.
2013-06-28 12:58:30 +02:00
Xiao Guangrong
f6f8adeef5 KVM: MMU: document fast invalidate all pages
Document it to Documentation/virtual/kvm/mmu.txt

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-06-27 14:20:47 +03:00
Xiao Guangrong
0cbf8e437b KVM: MMU: document write_flooding_count
Document write_flooding_count to Documentation/virtual/kvm/mmu.txt

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-06-27 14:20:43 +03:00
Xiao Guangrong
accaefe07d KVM: MMU: document clear_spte_count
Document it to Documentation/virtual/kvm/mmu.txt

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-06-27 14:20:42 +03:00
Xiao Guangrong
a8eca9dcc6 KVM: MMU: drop kvm_mmu_zap_mmio_sptes
Drop kvm_mmu_zap_mmio_sptes and use kvm_mmu_invalidate_zap_all_pages
instead to handle mmio generation number overflow

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-06-27 14:20:40 +03:00
Xiao Guangrong
f8f559422b KVM: MMU: fast invalidate all mmio sptes
This patch tries to introduce a very simple and scale way to invalidate
all mmio sptes - it need not walk any shadow pages and hold mmu-lock

KVM maintains a global mmio valid generation-number which is stored in
kvm->memslots.generation and every mmio spte stores the current global
generation-number into his available bits when it is created

When KVM need zap all mmio sptes, it just simply increase the global
generation-number. When guests do mmio access, KVM intercepts a MMIO #PF
then it walks the shadow page table and get the mmio spte. If the
generation-number on the spte does not equal the global generation-number,
it will go to the normal #PF handler to update the mmio spte

Since 19 bits are used to store generation-number on mmio spte, we zap all
mmio sptes when the number is round

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-06-27 14:20:36 +03:00
Dave Airlie
dc0216445c Merge branch 'core/mutexes' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into drm-next
Merge in the tip core/mutexes branch for future GPU driver use.

Ingo will send this branch to Linus prior to drm-next.

* 'core/mutexes' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
  locking-selftests: Handle unexpected failures more strictly
  mutex: Add more w/w tests to test EDEADLK path handling
  mutex: Add more tests to lib/locking-selftest.c
  mutex: Add w/w tests to lib/locking-selftest.c
  mutex: Add w/w mutex slowpath debugging
  mutex: Add support for wound/wait style locks
  arch: Make __mutex_fastpath_lock_retval return whether fastpath succeeded or not
  powerpc/pci: Fix boot panic on mpc83xx (regression)
  s390/ipl: Fix FCP WWPN and LUN format strings for read
  fs: fix new splice.c kernel-doc warning
  spi/pxa2xx: fix memory corruption due to wrong size used in devm_kzalloc()
  s390/mem_detect: fix memory hole handling
  s390/dma: support debug_dma_mapping_error
  s390/dma: fix mapping_error detection
  s390/irq: Only define synchronize_irq() on SMP
  Input: xpad - fix for "Mad Catz Street Fighter IV FightPad" controllers
  Input: wacom - add a new stylus (0x100802) for Intuos5 and Cintiqs
  spi/pxa2xx: use GFP_ATOMIC in sg table allocation
  fuse: hold i_mutex in fuse_file_fallocate()
  Input: add missing dependencies on CONFIG_HAS_IOMEM
  ...
2013-06-27 20:42:09 +10:00
Dave Airlie
4300a0f8bd Linux 3.10-rc7
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Merge tag 'v3.10-rc7' into drm-next

Linux 3.10-rc7

The sdvo lvds fix in this -fixes pull

commit c3456fb3e4
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Mon Jun 10 09:47:58 2013 +0200

    drm/i915: prefer VBT modes for SVDO-LVDS over EDID

has a silent functional conflict with

commit 990256aec2
Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date:   Fri May 31 12:17:07 2013 +0000

    drm: Add probed modes in probe order

in drm-next. W simply need to add the vbt modes before edid modes, i.e. the
other way round than now.

Conflicts:
	drivers/gpu/drm/drm_prime.c
	drivers/gpu/drm/i915/intel_sdvo.c
2013-06-27 20:40:44 +10:00
Maarten Lankhorst
a41b56efa7 arch: Make __mutex_fastpath_lock_retval return whether fastpath succeeded or not
This will allow me to call functions that have multiple
arguments if fastpath fails. This is required to support ticket
mutexes, because they need to be able to pass an extra argument
to the fail function.

Originally I duplicated the functions, by adding
__mutex_fastpath_lock_retval_arg. This ended up being just a
duplication of the existing function, so a way to test if
fastpath was called ended up being better.

This also cleaned up the reservation mutex patch some by being
able to call an atomic_set instead of atomic_xchg, and making it
easier to detect if the wrong unlock function was previously
used.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: dri-devel@lists.freedesktop.org
Cc: linaro-mm-sig@lists.linaro.org
Cc: robclark@gmail.com
Cc: rostedt@goodmis.org
Cc: daniel@ffwll.ch
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20130620113105.4001.83929.stgit@patser
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-06-26 12:10:55 +02:00
Ingo Molnar
ca02c21674 Better comments so we understand our existing machine check
bank bitmaps - prelude to adding another bitmap soon.
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Merge tag 'please-pull-mce-bitmap-comment' of git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras into x86/ras

Pull MCE updates from Tony Luck:

 "Better comments so we understand our existing machine check
  bank bitmaps - prelude to adding another bitmap soon."

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-06-26 10:53:45 +02:00
H. Peter Anvin
afcbf13fa6 x86: Rename X86_CR4_RDWRGSFS to X86_CR4_FSGSBASE
Rename X86_CR4_RDWRGSFS to X86_CR4_FSGSBASE to match the SDM.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Link: http://lkml.kernel.org/n/tip-buq1evi5dpykxx7ak6amaam0@git.kernel.org
2013-06-25 16:26:06 -07:00
Steven Rostedt (Red Hat)
2b4bc78956 trace,x86: Do not call local_irq_save() in load_current_idt()
As load_current_idt() is now what is used to update the IDT for the
switches needed for NMI, lockdep debug, and for tracing, it must not
call local_irq_save(). This is because one of the users of this is
lockdep, which does tracing of local_irq_save() and when the debug
trap is hit, we need to update the IDT before tracing interrupts
being disabled. As load_current_idt() is used to do this, calling
local_irq_save() which lockdep traces, defeats the point of calling
load_current_idt().

As interrupts are already disabled when used by lockdep and NMI, the
only other user is tracing that can disable interrupts itself. Simply
have the tracing update disable interrupts before calling load_current_idt()
instead of breaking the other users.

Here's the dump that happened:

------------[ cut here ]------------
WARNING: at /work/autotest/nobackup/linux-test.git/kernel/fork.c:1196 copy_process+0x2c3/0x1398()
DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled)
Modules linked in:
CPU: 1 PID: 4570 Comm: gdm-simple-gree Not tainted 3.10.0-rc3-test+ #5
Hardware name:                  /DG965MQ, BIOS MQ96510J.86A.0372.2006.0605.1717 06/05/2006
 ffffffff81d2a7a5 ffff88006ed13d50 ffffffff8192822b ffff88006ed13d90
 ffffffff81035f25 ffff8800721c6000 ffff88006ed13da0 0000000001200011
 0000000000000000 ffff88006ed5e000 ffff8800721c6000 ffff88006ed13df0
Call Trace:
 [<ffffffff8192822b>] dump_stack+0x19/0x1b
 [<ffffffff81035f25>] warn_slowpath_common+0x67/0x80
 [<ffffffff81035fe1>] warn_slowpath_fmt+0x46/0x48
 [<ffffffff812bfc5d>] ? __raw_spin_lock_init+0x31/0x52
 [<ffffffff810341f7>] copy_process+0x2c3/0x1398
 [<ffffffff8103539d>] do_fork+0xa8/0x260
 [<ffffffff810ca7b1>] ? trace_preempt_on+0x2a/0x2f
 [<ffffffff812afb3e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
 [<ffffffff81937fe7>] ? sysret_check+0x1b/0x56
 [<ffffffff81937fe7>] ? sysret_check+0x1b/0x56
 [<ffffffff810355cf>] SyS_clone+0x16/0x18
 [<ffffffff81938369>] stub_clone+0x69/0x90
 [<ffffffff81937fc2>] ? system_call_fastpath+0x16/0x1b
---[ end trace 8b157a9d20ca1aa2 ]---

in fork.c:

 #ifdef CONFIG_PROVE_LOCKING
	DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled); <-- bug here
	DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled);
 #endif

Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-06-22 13:16:19 -04:00
Jussi Kivilinna
99f42f937a Revert "crypto: twofish - add AVX2/x86_64 assembler implementation of twofish cipher"
This reverts commit cf1521a1a5.

Instruction (vpgatherdd) that this implementation relied on turned out to be
slow performer on real hardware (i5-4570). The previous 8-way twofish/AVX
implementation is therefore faster and this implementation should be removed.

Converting this implementation to use the same method as in twofish/AVX for
table look-ups would give additional ~3% speed up vs twofish/AVX, but would
hardly be worth of the added code and binary size.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2013-06-21 14:44:29 +08:00
Jussi Kivilinna
3d387ef08c Revert "crypto: blowfish - add AVX2/x86_64 implementation of blowfish cipher"
This reverts commit 6048801070.

Instruction (vpgatherdd) that this implementation relied on turned out to be
slow performer on real hardware (i5-4570). The previous 4-way blowfish
implementation is therefore faster and this implementation should be removed.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2013-06-21 14:44:28 +08:00
Seiji Aguchi
cf910e83ae x86, trace: Add irq vector tracepoints
[Purpose of this patch]

As Vaibhav explained in the thread below, tracepoints for irq vectors
are useful.

http://www.spinics.net/lists/mm-commits/msg85707.html

<snip>
The current interrupt traces from irq_handler_entry and irq_handler_exit
provide when an interrupt is handled.  They provide good data about when
the system has switched to kernel space and how it affects the currently
running processes.

There are some IRQ vectors which trigger the system into kernel space,
which are not handled in generic IRQ handlers.  Tracing such events gives
us the information about IRQ interaction with other system events.

The trace also tells where the system is spending its time.  We want to
know which cores are handling interrupts and how they are affecting other
processes in the system.  Also, the trace provides information about when
the cores are idle and which interrupts are changing that state.
<snip>

On the other hand, my usecase is tracing just local timer event and
getting a value of instruction pointer.

I suggested to add an argument local timer event to get instruction pointer before.
But there is another way to get it with external module like systemtap.
So, I don't need to add any argument to irq vector tracepoints now.

[Patch Description]

Vaibhav's patch shared a trace point ,irq_vector_entry/irq_vector_exit, in all events.
But there is an above use case to trace specific irq_vector rather than tracing all events.
In this case, we are concerned about overhead due to unwanted events.

So, add following tracepoints instead of introducing irq_vector_entry/exit.
so that we can enable them independently.
   - local_timer_vector
   - reschedule_vector
   - call_function_vector
   - call_function_single_vector
   - irq_work_entry_vector
   - error_apic_vector
   - thermal_apic_vector
   - threshold_apic_vector
   - spurious_apic_vector
   - x86_platform_ipi_vector

Also, introduce a logic switching IDT at enabling/disabling time so that a time penalty
makes a zero when tracepoints are disabled. Detailed explanations are as follows.
 - Create trace irq handlers with entering_irq()/exiting_irq().
 - Create a new IDT, trace_idt_table, at boot time by adding a logic to
   _set_gate(). It is just a copy of original idt table.
 - Register the new handlers for tracpoints to the new IDT by introducing
   macros to alloc_intr_gate() called at registering time of irq_vector handlers.
 - Add checking, whether irq vector tracing is on/off, into load_current_idt().
   This has to be done below debug checking for these reasons.
   - Switching to debug IDT may be kicked while tracing is enabled.
   - On the other hands, switching to trace IDT is kicked only when debugging
     is disabled.

In addition, the new IDT is created only when CONFIG_TRACING is enabled to avoid being
used for other purposes.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/51C323ED.5050708@hds.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
2013-06-20 22:25:34 -07:00
Seiji Aguchi
629f4f9d59 x86: Rename variables for debugging
Rename variables for debugging to describe meaning of them precisely.

Also, introduce a generic way to switch IDT by checking a current state,
debug on/off.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/51C323A8.7050905@hds.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
2013-06-20 22:25:13 -07:00
Seiji Aguchi
eddc0e922a x86, trace: Introduce entering/exiting_irq()
When implementing tracepoints in interrupt handers, if the tracepoints are
simply added in the performance sensitive path of interrupt handers,
it may cause potential performance problem due to the time penalty.

To solve the problem, an idea is to prepare non-trace/trace irq handers and
switch their IDTs at the enabling/disabling time.

So, let's introduce entering_irq()/exiting_irq() for pre/post-
processing of each irq handler.

A way to use them is as follows.

Non-trace irq handler:
smp_irq_handler()
{
	entering_irq();		/* pre-processing of this handler */
	__smp_irq_handler();	/*
				 * common logic between non-trace and trace handlers
				 * in a vector.
				 */
	exiting_irq();		/* post-processing of this handler */

}

Trace irq_handler:
smp_trace_irq_handler()
{
	entering_irq();		/* pre-processing of this handler */
	trace_irq_entry();	/* tracepoint for irq entry */
	__smp_irq_handler();	/*
				 * common logic between non-trace and trace handlers
				 * in a vector.
				 */
	trace_irq_exit();	/* tracepoint for irq exit */
	exiting_irq();		/* post-processing of this handler */

}

If tracepoints can place outside entering_irq()/exiting_irq() as follows,
it looks cleaner.

smp_trace_irq_handler()
{
	trace_irq_entry();
	smp_irq_handler();
	trace_irq_exit();
}

But it doesn't work.
The problem is with irq_enter/exit() being called. They must be called before
trace_irq_enter/exit(),  because of the rcu_irq_enter() must be called before
any tracepoints are used, as tracepoints use  rcu to synchronize.

As a possible alternative, we may be able to call irq_enter() first as follows
if irq_enter() can nest.

smp_trace_irq_hander()
{
	irq_entry();
	trace_irq_entry();
	smp_irq_handler();
	trace_irq_exit();
	irq_exit();
}

But it doesn't work, either.
If irq_enter() is nested, it may have a time penalty because it has to check if it
was already called or not. The time penalty is not desired in performance sensitive
paths even if it is tiny.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/51C3238D.9040706@hds.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
2013-06-20 22:25:01 -07:00
H. Peter Anvin
e6bca5a6a8 Linux 3.10-rc6
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Merge tag 'v3.10-rc6' into x86/cleanups

Linux 3.10-rc6

We need a change that is the mainline tree for further work.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2013-06-20 21:13:55 -07:00
Borislav Petkov
5f8c421814 x86, fpu: Use static_cpu_has_safe before alternatives
The call stack below shows how this happens: basically eager_fpu_init()
calls __thread_fpu_begin(current) which then does if (!use_eager_fpu()),
which, in turn, uses static_cpu_has.

And we're executing before alternatives so static_cpu_has doesn't work
there yet.

Use the safe variant in this path which becomes optimal after
alternatives have run.

WARNING: at arch/x86/kernel/cpu/common.c:1368 warn_pre_alternatives+0x1e/0x20()
You're using static_cpu_has before alternatives have run!
Modules linked in:
Pid: 0, comm: swapper Not tainted 3.9.0-rc8+ #1
Call Trace:
 warn_slowpath_common
 warn_slowpath_fmt
 ? fpu_finit
 warn_pre_alternatives
 eager_fpu_init
 fpu_init
 cpu_init
 trap_init
 start_kernel
 ? repair_env_string
 x86_64_start_reservations
 x86_64_start_kernel

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1370772454-6106-6-git-send-email-bp@alien8.de
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2013-06-20 17:38:22 -07:00