Skip to content

L
linux
Switch branch/tag
  1. 04 Feb, 2015 12 commits
  3. 03 Feb, 2015 3 commits
  5. 02 Feb, 2015 1 commit
  7. 01 Feb, 2015 8 commits
    • Linus Torvalds's avatar
      Merge tag 'armsoc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc · fba7e994
      Linus Torvalds authored 
      Pull ARM SoC fixes from Olof Johansson:
 "One more week's worth of fixes.  Worth pointing out here are:

   - A patch fixing detaching of iommu registrations when a device is
     removed -- earlier the ops pointer wasn't managed properly
   - Another set of Renesas boards get the same GIC setup fixup as
     others have in previous -rcs
   - Serial port aliases fixups for sunxi.  We did the same to tegra but
     we caught that in time before the merge window due to more machines
     being affected.  Here it took longer for anyone to notice.
   - A couple more DT tweaks on sunxi
   - A follow-up patch for the mvebu coherency disabling in last -rc
     batch"

* tag 'armsoc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  arm: dma-mapping: Set DMA IOMMU ops in arm_iommu_attach_device()
  ARM: shmobile: r8a7790: Instantiate GIC from C board code in legacy builds
  ARM: shmobile: r8a73a4: Instantiate GIC from C board code in legacy builds
  ARM: mvebu: don't set the PL310 in I/O coherency mode when I/O coherency is disabled
  ARM: sunxi: dt: Fix aliases
  ARM: dts: sun4i: Add simplefb node with de_fe0-de_be0-lcd0-hdmi pipeline
  ARM: dts: sun6i: ippo-q8h-v5: Fix serial0 alias
  ARM: dts: sunxi: Fix usb-phy support for sun4i/sun5i
      fba7e994
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input · 3441456b
      Linus Torvalds authored 
      Pull input layer updates from Dmitry Torokhov:
 "Just a few quirks for PS/2 this time"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: elantech - add more Fujtisu notebooks to force crc_enabled
  Input: i8042 - add noloop quirk for Medion Akoya E7225 (MD98857)
  Input: synaptics - adjust min/max for Lenovo ThinkPad X1 Carbon 2nd
      3441456b
    • Linus Torvalds's avatar
      sched: don't cause task state changes in nested sleep debugging · 00845eb9
      Linus Torvalds authored 
      Commit 8eb23b9f ("sched: Debug nested sleeps") added code to report
on nested sleep conditions, which we generally want to avoid because the
inner sleeping operation can re-set the thread state to TASK_RUNNING,
but that will then cause the outer sleep loop not actually sleep when it
calls schedule.

However, that's actually valid traditional behavior, with the inner
sleep being some fairly rare case (like taking a sleeping lock that
normally doesn't actually need to sleep).

And the debug code would actually change the state of the task to
TASK_RUNNING internally, which makes that kind of traditional and
working code not work at all, because now the nested sleep doesn't just
sometimes cause the outer one to not block, but will cause it to happen
every time.

In particular, it will cause the cardbus kernel daemon (pccardd) to
basically busy-loop doing scheduling, converting a laptop into a heater,
as reported by Bruno Prémont.  But there may be other legacy uses of
that nested sleep model in other drivers that are also likely to never
get converted to the new model.

This fixes both cases:

 - don't set TASK_RUNNING when the nested condition happens (note: even
   if WARN_ONCE() only _warns_ once, the return value isn't whether the
   warning happened, but whether the condition for the warning was true.
   So despite the warning only happening once, the "if (WARN_ON(..))"
   would trigger for every nested sleep.

 - in the cases where we knowingly disable the warning by using
   "sched_annotate_sleep()", don't change the task state (that is used
   for all core scheduling decisions), instead use '->task_state_change'
   that is used for the debugging decision itself.

(Credit for the second part of the fix goes to Oleg Nesterov: "Can't we
avoid this subtle change in behaviour DEBUG_ATOMIC_SLEEP adds?" with the
suggested change to use 'task_state_change' as part of the test)
Reported-and-bisected-by: default avatarBruno Prémont <bonbons@linux-vserver.org>
Tested-by: default avatarRafael J Wysocki <rjw@rjwysocki.net>
Acked-by: default avatarOleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Cc: Ilya Dryomov <ilya.dryomov@inktank.com>,
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Hurley <peter@hurleysoftware.com>,
Cc: Davidlohr Bueso <dave@stgolabs.net>,
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      00845eb9
    • Rainer Koenig's avatar
      Input: elantech - add more Fujtisu notebooks to force crc_enabled · 47c1ffb2
      Rainer Koenig authored 
      Add two more Fujitsu LIFEBOOK models that also ship with the Elantech
touchpad and don't work with crc_disabled to the quirk list.
Signed-off-by: default avatarRainer Koenig <Rainer.Koenig@ts.fujitsu.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
      47c1ffb2
    • Olof Johansson's avatar
      Merge tag 'renesas-soc-fixes3-for-v3.19' of... · 28111dda
      Olof Johansson authored 
      Merge tag 'renesas-soc-fixes3-for-v3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas into fixes

Merge "Third Round of Renesas ARM Based SoC Fixes for v3.19" from Simon Horman:

* Instantiate GIC from C board code in legacy builds on r8a7790 and r8a73a4

* tag 'renesas-soc-fixes3-for-v3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas:
  ARM: shmobile: r8a7790: Instantiate GIC from C board code in legacy builds
  ARM: shmobile: r8a73a4: Instantiate GIC from C board code in legacy builds
Signed-off-by: default avatarOlof Johansson <olof@lixom.net>
      28111dda
    • Andy Lutomirski's avatar
      x86_64, entry: Remove the syscall exit audit and schedule optimizations · 96b6352c
      Andy Lutomirski authored 
      We used to optimize rescheduling and audit on syscall exit.  Now
that the full slow path is reasonably fast, remove these
optimizations.  Syscall exit auditing is now handled exclusively by
syscall_trace_leave.

This adds something like 10ns to the previously optimized paths on
my computer, presumably due mostly to SAVE_REST / RESTORE_REST.

I think that we should eventually replace both the syscall and
non-paranoid interrupt exit slow paths with a pair of C functions
along the lines of the syscall entry hooks.

Link: http://lkml.kernel.org/r/22f2aa4a0361707a5cfb1de9d45260b39965dead.1421453410.git.luto@amacapital.netAcked-by: default avatarBorislav Petkov <bp@suse.de>
Signed-off-by: default avatarAndy Lutomirski <luto@amacapital.net>
      96b6352c
    • Andy Lutomirski's avatar
      x86_64, entry: Use sysret to return to userspace when possible · 2a23c6b8
      Andy Lutomirski authored 
      The x86_64 entry code currently jumps through complex and
inconsistent hoops to try to minimize the impact of syscall exit
work.  For a true fast-path syscall, almost nothing needs to be
done, so returning is just a check for exit work and sysret.  For a
full slow-path return from a syscall, the C exit hook is invoked if
needed and we join the iret path.

Using iret to return to userspace is very slow, so the entry code
has accumulated various special cases to try to do certain forms of
exit work without invoking iret.  This is error-prone, since it
duplicates assembly code paths, and it's dangerous, since sysret
can malfunction in interesting ways if used carelessly.  It's
also inefficient, since a lot of useful cases aren't optimized
and therefore force an iret out of a combination of paranoia and
the fact that no one has bothered to write even more asm code
to avoid it.

I would argue that this approach is backwards.  Rather than trying
to avoid the iret path, we should instead try to make the iret path
fast.  Under a specific set of conditions, iret is unnecessary.  In
particular, if RIP==RCX, RFLAGS==R11, RIP is canonical, RF is not
set, and both SS and CS are as expected, then
movq 32(%rsp),%rsp;sysret does the same thing as iret.  This set of
conditions is nearly always satisfied on return from syscalls, and
it can even occasionally be satisfied on return from an irq.

Even with the careful checks for sysret applicability, this cuts
nearly 80ns off of the overhead from syscalls with unoptimized exit
work.  This includes tracing and context tracking, and any return
that invokes KVM's user return notifier.  For example, the cost of
getpid with CONFIG_CONTEXT_TRACKING_FORCE=y drops from ~360ns to
~280ns on my computer.

This may allow the removal and even eventual conversion to C
of a respectable amount of exit asm.

This may require further tweaking to give the full benefit on Xen.

It may be worthwhile to adjust signal delivery and exec to try hit
the sysret path.

This does not optimize returns to 32-bit userspace.  Making the same
optimization for CS == __USER32_CS is conceptually straightforward,
but it will require some tedious code to handle the differences
between sysretl and sysexitl.

Link: http://lkml.kernel.org/r/71428f63e681e1b4aa1a781e3ef7c27f027d1103.1421453410.git.luto@amacapital.netSigned-off-by: default avatarAndy Lutomirski <luto@amacapital.net>
      2a23c6b8
    • Andy Lutomirski's avatar
      x86, traps: Fix ist_enter from userspace · b926e6f6
      Andy Lutomirski authored 
      context_tracking_user_exit() has no effect if in_interrupt() returns true,
so ist_enter() didn't work.  Fix it by calling exception_enter(), and thus
context_tracking_user_exit(), before incrementing the preempt count.

This also adds an assertion that will catch the problem reliably if
CONFIG_PROVE_RCU=y to help prevent the bug from being reintroduced.

Link: http://lkml.kernel.org/r/261ebee6aee55a4724746d0d7024697013c40a08.1422709102.git.luto@amacapital.net
Fixes: 95927475 x86, traps: Track entry into and exit from IST context
Reported-and-tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
Signed-off-by: default avatarAndy Lutomirski <luto@amacapital.net>
      b926e6f6
  9. 31 Jan, 2015 4 commits
  11. 30 Jan, 2015 12 commits
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7