drm/i915: Avoid div-by-zero when pixel_multiplier is zero

On certain platforms pixel_multiplier is read out in
.get_pipe_config(), but it also gets used to calculate the
pixel clock in intel_sdvo_get_config(). If the pipe is disable
but some SDVO outputs are active, we may end up dividing by zero
in intel_sdvo_get_config().

To avoid the problem simply check for zero pixel_multiplier and skip
the division. Another attempt at fixing this involved populating
pixel_multiplier to 1 even for disabled pipes, but that triggered a
WARN because SDVO_CMD_GET_CLOCK_RATE_MULT command failed and thus
encoder_pixel_multiplier was left at zero and didn't match
pipe_config->pixel_multiplier.

The "divide by pixel_multiplier" operation got introduced here:
 commit 18442d08786472c63a0a80c27f92b033dffc26de
 Author: Ville SyrjÃ¤lÃ¤ <ville.syrjala@linux.intel.com>
 Date:   Fri Sep 13 16:00:08 2013 +0300

    drm/i915: Fix port_clock and adjusted_mode.clock readout all over

and it has caused a regression on certain machines since they would
hit the div-by-zero during resume.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=76520
Cc: <stable@vger.kernel.org> # 3.13+
Tested-by: Tim Richardson <tim@tim-richardson.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
drm/i915: set backlight duty cycle after backlight enable for gen4

For reasons I can't claim to fully understand gen4 seems to require
backlight duty cycle setting after the backlight has been enabled, or
else black screen follows. I don't have documentation for the correct
sequence on gen4 either. Confirmed on Dell Latitude D630 and MacBook4,1.

This fixes a regression introduced by
commit b35684b8fa94e04f55fd38bf672b737741d2f9e2
Author: Jani Nikula <jani.nikula@intel.com>
Date:   Thu Nov 14 12:13:41 2013 +0200

    drm/i915: do full backlight setup at enable time

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=75791
Reported-and-tested-by: mcy@lm7.fr
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=79423
Reported-and-tested-by: Marc Milgram <mmilgram@redhat.com>
Cc: Stable <stable@vger.kernel.org> # 3.14+
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
drm/i95: Initialize active ring->pid to -1

Otherwise we print out spurious processes on unused rings in the error
state.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@vger.kernel.org
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
drm/i915: Reorder semaphore deadlock check

If a semaphore is waiting on another ring, which in turn happens to be
waiting on the first ring, but that second semaphore has been signalled,
we will be able to kick the second ring and so can treat the first ring
as a valid WAIT and not as HUNG.

v2: Be paranoid and cap the potential recursion depth whilst visiting
the semaphore signallers. (Mika)

References: https://bugs.freedesktop.org/show_bug.cgi?id=54226
References: https://bugs.freedesktop.org/show_bug.cgi?id=75502
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: stable@vger.kernel.org
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
drm/i915: fix possible refcount leak when resetting forcewake

If the timer putting the last forcewake refcount was pending and we
canceled it, we'll leak the corresponding forcewake and RPM references.

v2:
- do the ptr casting at the caller instead of adding a separate helper
  for this (Chris)

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
s390: avoid format strings leaking into names

This makes sure format strings can't accidentally leak into kernel
interface names.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
s390: update default configuration

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
clk: sunxi: Rework clock protection code

Since we start to have a lot of clocks to protect, some of them in a
few SoCs only, it becomes difficult to handle the clock protection
without having to add per machine exceptions.

Add per-SoC data to tell which clock to leave enabled.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Emilio López <emilio@elopez.com.ar>
clk: sun6i: Protect CPU clock

Right now, AHB is an indirect child clock of the CPU clock. If that
happens to change, since the CPU clock has no other consumers declared
in Linux, it would be shut down, which is not really a good idea.

Prevent this by forcing it enabled.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Emilio López <emilio@elopez.com.ar>
clk: sun6i: Protect SDRAM gating bit

Prevent the SDRAM controller from being gated by force-enabling it in the
machine code.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Emilio López <emilio@elopez.com.ar>
clk: sunxi: add PRCM (Power/Reset/Clock Management) clks support

The PRCM (Power/Reset/Clock Management) unit provides several clock
devices:
- AR100 clk: used to clock the Power Management co-processor
- AHB0 clk: used to clock the AHB0 bus
- APB0 clk and gates: used to clk peripherals connected to the APB0 bus

Add support for these clks in a separate driver so that they can be probed
as platform devices instead of registered during early init.
This is needed to be able to probe PRCM MFD subdevices.

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Emilio López <emilio@elopez.com.ar>
clk: sunxi: document PRCM clock compatible strings

Document new compatible strings for clock provided by the PRCM
(Power/Reset/Clock Management) unit.

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Signed-off-by: Emilio López <emilio@elopez.com.ar>
Merge remote-tracking branch 'drm-intel/topic/kicking-dogs-and-vgacon' into drm-intel-fixes

vt/vgacon fixes to avoid hangs, unclaimed register errors on module
load, reload:

vt: Fix replacement console check when unbinding
vt: Fix up unregistration of vt drivers
vt: Don't ignore unbind errors in vt_unbind
drm/i915: Fixup global gtt cleanup
drm/i915: Kick out vga console

Link: http://lkml.kernel.org/r/1401980308-5116-1-git-send-email-daniel.vetter@ffwll.ch
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
powerpc/eeh: Dump PE location code

As Ben suggested, it's meaningful to dump PE's location code
for site engineers when hitting EEH errors. The patch introduces
function eeh_pe_loc_get() to retireve the location code from
dev-tree so that we can output it when hitting EEH errors.

If primary PE bus is root bus, the PHB's dev-node would be tried
prior to root port's dev-node. Otherwise, the upstream bridge's
dev-node of the primary PE bus will be check for the location code
directly.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
powerpc/book3s: Fix machine check handling for unhandled errors

Current code does not check for unhandled/unrecovered errors and return from
interrupt if it is recoverable exception which in-turn triggers same machine
check exception in a loop causing hypervisor to be unresponsive.

This patch fixes this situation and forces hypervisor to panic for
unhandled/unrecovered errors.

This patch also fixes another issue where unrecoverable_exception routine
was called in real mode in case of unrecoverable exception (MSR_RI = 0).
This causes another exception vector 0x300 (data access) during system crash
leading to confusion while debugging cause of the system crash.

Also turn ME bit off while going down, so that when another MCE is hit during
panic path, system will checkstop and hypervisor will get restarted cleanly
by SP.

With the above fixes we now throw correct console messages (see below) while
crashing the system in case of unhandled/unrecoverable machine checks.

--------------
Severe Machine check interrupt [[Not recovered]
  Initiator: CPU
  Error type: UE [Instruction fetch]
    Effective address: 0000000030002864
Oops: Machine check, sig: 7 [#1]
SMP NR_CPUS=2048 NUMA PowerNV
Modules linked in: bork(O) bridge stp llc kvm [last unloaded: bork]
CPU: 36 PID: 55162 Comm: bash Tainted: G           O 3.14.0mce #1
task: c000002d72d022d0 ti: c000000007ec0000 task.ti: c000002d72de4000
NIP: 0000000030002864 LR: 00000000300151a4 CTR: 000000003001518c
REGS: c000000007ec3d80 TRAP: 0200   Tainted: G           O  (3.14.0mce)
MSR: 9000000000041002 <SF,HV,ME,RI>  CR: 28222848  XER: 20000000
CFAR: 0000000030002838 DAR: d0000000004d0000 DSISR: 00000000 SOFTE: 1
GPR00: 000000003001512c 0000000031f92cb0 0000000030078af0 0000000030002864
GPR04: d0000000004d0000 0000000000000000 0000000030002864 ffffffffffffffc9
GPR08: 0000000000000024 0000000030008af0 000000000000002c c00000000150e728
GPR12: 9000000000041002 0000000031f90000 0000000010142550 0000000040000000
GPR16: 0000000010143cdc 0000000000000000 00000000101306fc 00000000101424dc
GPR20: 00000000101424e0 000000001013c6f0 0000000000000000 0000000000000000
GPR24: 0000000010143ce0 00000000100f6440 c000002d72de7e00 c000002d72860250
GPR28: c000002d72860240 c000002d72ac0038 0000000000000008 0000000000040000
NIP [0000000030002864] 0x30002864
LR [00000000300151a4] 0x300151a4
Call Trace:
Instruction dump:
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
---[ end trace 7285f0beac1e29d3 ]---

Sending IPI to other CPUs
IPI complete
OPAL V3 detected !
--------------

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
powerpc/book3s: Add stack overflow check in machine check handler.

Currently machine check handler does not check for stack overflow for
nested machine check. If we hit another MCE while inside the machine check
handler repeatedly from same address then we get into risk of stack
overflow which can cause huge memory corruption. This patch limits the
nested MCE level to 4 and panic when we cross level 4.

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
powerpc/book3s: Increment the mce counter during machine_check_early call.

We don't see MCE counter getting increased in /proc/interrupts which gives
false impression of no MCE occurred even when there were MCE events.
The machine check early handling was added for PowerKVM and we missed to
increment the MCE count in the early handler.

We also increment mce counters in the machine_check_exception call, but
in most cases where we handle the error hypervisor never reaches there
unless its fatal and we want to crash. Only during fatal situation we may
see double increment of mce count. We need to fix that. But for
now it always good to have some count increased instead of zero.

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
powerpc/book3s: Fix guest MC delivery mechanism to avoid soft lockups in guest.

Currently we forward MCEs to guest which have been recovered by guest.
And for unhandled errors we do not deliver the MCE to guest. It looks like
with no support of FWNMI in qemu, guest just panics whenever we deliver the
recovered MCEs to guest. Also, the existig code used to return to host for
unhandled errors which was casuing guest to hang with soft lockups inside
guest and makes it difficult to recover guest instance.

This patch now forwards all fatal MCEs to guest causing guest to crash/panic.
And, for recovered errors we just go back to normal functioning of guest
instead of returning to host. This fixes soft lockup issues in guest.
This patch also fixes an issue where guest MCE events were not logged to
host console.

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Merge tag 'sunxi-clk-for-3.16-2' of https://github.com/mripard/linux into clk-next

Rebase of Emilio's clk-sunxi-for-3.16 on top of clk-next

Fixed a few compilation warnings exposed by a patch introduced during the 3.16
merge window.

Original tag message:

Allwinner sunXi SoCs clock changes

This pull contains some new code to add support for A31 clocks by Maxime
and Boris. It also reworks the driver a bit to avoid having a huge
single file when we have a full folder for ourselves, and separating
different functional units makes sense.
reiserfs: Fix compilation breakage with CONFIG_REISERFS_CHECK

There was a bug in debug printout when CONFIG_REISERFS_CHECK was
enabled so one of the assertions in do_balan.c didn't compile. Fix it.

Fixes: 0080e9f9d3ac717537dbd6db1fc8ef72ce0b9cc1
Signed-off-by: Jan Kara <jack@suse.cz>