pch_uart: Add eg20t_port lock field, avoid recursive spinlocks

commit 2588aba002d14e938c2f56d299ecf3e7ce1302a5 upstream.

pch_uart_interrupt() takes priv->port.lock which leads to two recursive
spinlock calls if low_latency==1 or CONFIG_PREEMPT_RT_FULL=y (one
otherwise):

pch_uart_interrupt
  spin_lock_irqsave(priv->port.lock, flags)
  case PCH_UART_IID_RDR_TO (data ready)
  handle_rx_to
    push_rx
      tty_port_tty_get
        spin_lock_irqsave(&port->lock, flags) <--- already hold this lock
        ...
      tty_flip_buffer_push
        ...
        flush_to_ldisc
          spin_lock_irqsave(&tty->buf.lock)
            spin_lock_irqsave(&tty->buf.lock)
            disc->ops->receive_buf(tty, char_buf)
              n_tty_receive_buf
                tty->ops->flush_chars()
                uart_flush_chars
                  uart_start
                    spin_lock_irqsave(&port->lock) <--- already hold this lock

Avoid this by using a dedicated lock to protect the eg20t_port structure
and IO access to its membase. This is more consistent with the 8250
driver.  Ensure priv->lock is always take prior to priv->port.lock when
taken at the same time.

V2: Remove inadvertent whitespace change.
V3: Account for oops_in_progress for the private lock in
    pch_console_write().

Note: Like the 8250 driver, if a printk is introduced anywhere inside
      the pch_console_write() critical section, the kernel will hang
      on a recursive spinlock on the private lock. The oops case is
      handled by using a trylock in the oops_in_progress case.

Signed-off-by: Darren Hart <dvhart@linux.intel.com>
CC: Tomoya MORINAGA <tomoya.rohm@gmail.com>
CC: Feng Tang <feng.tang@intel.com>
CC: Alexander Stein <alexander.stein@systec-electronic.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2:
 - Adjust context
 - Drop changes to pch_console_write()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
irq_remap: disable IRQ remapping if any IOAPIC lacks an IOMMU

commit 32ab31e01e2def6f48294d872d9bb42573aae00f upstream.

The ACPI tables in the Macbook Air 5,1 define a single IOAPIC with id 2,
but the only remapping unit described in the DMAR table matches id 0.
Interrupt remapping fails as a result, and the kernel panics with the
message "timer doesn't work through Interrupt-remapped IO-APIC."

To fix this, check each IOAPIC for a corresponding IOMMU. If an IOMMU is
not found, do not allow IRQ remapping to be enabled.

v2: Move check to parse_ioapics_under_ir(), raise log level to KERN_ERR,
    and add FW_BUG to the log message
v3: Skip check if IOMMU doesn't support interrupt remapping and remove
    existing check that the IOMMU count equals the IOAPIC count

Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
vfs: dcache: fix deadlock in tree traversal

commit 8110e16d42d587997bcaee0c864179e6d93603fe upstream.

IBM reported a deadlock in select_parent().  This was found to be caused
by taking rename_lock when already locked when restarting the tree
traversal.

There are two cases when the traversal needs to be restarted:

 1) concurrent d_move(); this can only happen when not already locked,
    since taking rename_lock protects against concurrent d_move().

 2) racing with final d_put() on child just at the moment of ascending
    to parent; rename_lock doesn't protect against this rare race, so it
    can happen when already locked.

Because of case 2, we need to be able to handle restarting the traversal
when rename_lock is already held.  This patch fixes all three callers of
try_to_ascend().

IBM reported that the deadlock is gone with this patch.

[ I rewrote the patch to be smaller and just do the "goto again" if the
  lock was already held, but credit goes to Miklos for the real work.
   - Linus ]

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
usb: gadget: dummy_hcd: fixup error probe path

commit 1b68a4ca2d038addb7314211d122fb6d7002b38b upstream.

If USB2 host controller probes fine but USB3 does not then we don't
remove the USB controller properly and lock up the system while the HUB
code will try to enumerate the USB2 controller and access memory which
is no longer available in case the dummy_hcd was compiled as a module.

This is a problem since 448b6eb1 ("USB: Make sure to fetch the BOS desc
for roothubs.) if used in USB3 mode because dummy does not provide this
descriptor and explodes later.

Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
CPU hotplug, cpusets, suspend: Don't modify cpusets during suspend/resume

commit d35be8bab9b0ce44bed4b9453f86ebf64062721e upstream.

In the event of CPU hotplug, the kernel modifies the cpusets' cpus_allowed
masks as and when necessary to ensure that the tasks belonging to the cpusets
have some place (online CPUs) to run on. And regular CPU hotplug is
destructive in the sense that the kernel doesn't remember the original cpuset
configurations set by the user, across hotplug operations.

However, suspend/resume (which uses CPU hotplug) is a special case in which
the kernel has the responsibility to restore the system (during resume), to
exactly the same state it was in before suspend.

In order to achieve that, do the following:

1. Don't modify cpusets during suspend/resume. At all.
   In particular, don't move the tasks from one cpuset to another, and
   don't modify any cpuset's cpus_allowed mask. So, simply ignore cpusets
   during the CPU hotplug operations that are carried out in the
   suspend/resume path.

2. However, cpusets and sched domains are related. We just want to avoid
   altering cpusets alone. So, to keep the sched domains updated, build
   a single sched domain (containing all active cpus) during each of the
   CPU hotplug operations carried out in s/r path, effectively ignoring
   the cpusets' cpus_allowed masks.

   (Since userspace is frozen while doing all this, it will go unnoticed.)

3. During the last CPU online operation during resume, build the sched
   domains by looking up the (unaltered) cpusets' cpus_allowed masks.
   That will bring back the system to the same original state as it was in
   before suspend.

Ultimately, this will not only solve the cpuset problem related to suspend
resume (ie., restores the cpusets to exactly what it was before suspend, by
not touching it at all) but also speeds up suspend/resume because we avoid
running cpuset update code for every CPU being offlined/onlined.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
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/20120524141611.3692.20155.stgit@srivatsabhat.in.ibm.com
[Preeti U Murthy: Please apply this patch to the stable tree 3.0.y]
Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Revert "drm/radeon: rework pll selection (v3)"

commit 2f1f4d9b60396d2df4cff829bd5376ffc8ed9a2c upstream.

This reverts commit 985f61f7ee647ad570c05eab0b74915da2ac8e19.

This commit fixed certain cases, but ended up regressing others
due to limitations in the current KMS API.  A proper fix is too
invasive for 3.6.  Push it back to 3.7.

Reported-by: Andres Freund <andres@anarazel.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[bwh: Backported to 3.2: drop the DCE6 case]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
x86/alternatives: Fix p6 nops on non-modular kernels

commit cb09cad44f07044d9810f18f6f9a6a6f3771f979 upstream.

Probably a leftover from the early days of self-patching, p6nops
are marked __initconst_or_module, which causes them to be
discarded in a non-modular kernel.  If something later triggers
patching, it will overwrite kernel code with garbage.

Reported-by: Tomas Racek <tracek@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Cc: Michael Tokarev <mjt@tls.msk.ru>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: qemu-devel@nongnu.org
Cc: Anthony Liguori <anthony@codemonkey.ws>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Alan Cox <alan@linux.intel.com>
Link: http://lkml.kernel.org/r/5034AE84.90708@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
HID: hidraw: add proper error handling to raw event reporting

commit b6787242f32700377d3da3b8d788ab3928bab849 upstream.

If kmemdup() in hidraw_report_event() fails, we are not propagating
this fact properly.

Let hidraw_report_event() and hid_report_raw_event() return an error
value to the caller.

Reported-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
HID: fix return value of hidraw_report_event() when !CONFIG_HIDRAW

commit d6d7c873529abd622897cad5e36f1fd7d82f5110 upstream.

Commit b6787242f327 ("HID: hidraw: add proper error handling to raw event
reporting") forgot to update the static inline version of
hidraw_report_event() for the case when CONFIG_HIDRAW is unset. Fix that
up.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
HID: hidraw: fix list->buffer memleak

commit 4c7b417ecb756e85dfc955b0e7a04fd45585533e upstream.

If we don't read fast enough hidraw device, hidraw_report_event
will cycle and we will leak list->buffer.
Also list->buffer are not free on release.
After this patch, kmemleak report nothing.

Signed-off-by: Matthieu CASTET <matthieu.castet@parrot.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>