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  1. 24 7月, 2018 11 次提交
    • L
      PCI: pciehp: Handle events synchronously · 0e94916e
      由 Lukas Wunner 提交于 
      Up until now, pciehp's IRQ handler schedules a work item for each event,
which in turn schedules a work item to enable or disable the slot.  This
double indirection was necessary because sleeping wasn't allowed in the
IRQ handler.

However it is now that pciehp has been converted to threaded IRQ handling
and polling, so handle events synchronously in pciehp_ist() and remove
the work item infrastructure (with the exception of work items to handle
a button press after the 5 second delay).

For link or presence change events, move the register read to determine
the current link or presence state behind acquisition of the slot lock
to prevent it from becoming stale while the lock is contended.
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
      0e94916e
    • L
      PCI: pciehp: Stop blinking on slot enable failure · b0ccd9dd
      由 Lukas Wunner 提交于 
      If the attention button is pressed to power on the slot AND the user
powers on the slot via sysfs before 5 seconds have elapsed AND powering
on the slot fails because either the slot is unoccupied OR the latch is
open, we neglect turning off the green LED so it keeps on blinking.

That's because the error path of pciehp_sysfs_enable_slot() doesn't call
pciehp_green_led_off(), unlike pciehp_power_thread() which does.
The bug has been present since 2004 when the driver was introduced.

Fix by deduplicating common code in pciehp_sysfs_enable_slot() and
pciehp_power_thread() into a wrapper function pciehp_enable_slot() and
renaming the existing function to __pciehp_enable_slot().  Same for
pciehp_disable_slot().  This will also simplify the upcoming rework of
pciehp's event handling.
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
      b0ccd9dd
    • L
      PCI: pciehp: Convert to threaded polling · ec07a447
      由 Lukas Wunner 提交于 
      We've just converted pciehp to threaded IRQ handling, but still cannot
sleep in pciehp_ist() because the function is also called in poll mode,
which runs in softirq context (from a timer).

Convert poll mode to a kthread so that pciehp_ist() always runs in task
context.
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
      ec07a447
    • L
      PCI: pciehp: Convert to threaded IRQ · 7b4ce26b
      由 Lukas Wunner 提交于 
      pciehp's IRQ handler queues up a work item for each event signaled by
the hardware.  A more modern alternative is to let a long running
kthread service the events.  The IRQ handler's sole job is then to check
whether the IRQ originated from the device in question, acknowledge its
receipt to the hardware to quiesce the interrupt and wake up the kthread.

One benefit is reduced latency to handle the IRQ, which is a necessity
for realtime environments.  Another benefit is that we can make pciehp
simpler and more robust by handling events synchronously in process
context, rather than asynchronously by queueing up work items.  pciehp's
usage of work items is a historic artifact, it predates the introduction
of threaded IRQ handlers by two years.  (The former was introduced in
2007 with commit 5d386e1a ("pciehp: Event handling rework"), the
latter in 2009 with commit 3aa551c9 ("genirq: add threaded interrupt
handler support").)

Convert pciehp to threaded IRQ handling by retrieving the pending events
in pciehp_isr(), saving them for later consumption by the thread handler
pciehp_ist() and clearing them in the Slot Status register.

By clearing the Slot Status (and thereby acknowledging the events) in
pciehp_isr(), we can avoid requesting the IRQ with IRQF_ONESHOT, which
would have the unpleasant side effect of starving devices sharing the
IRQ until pciehp_ist() has finished.

pciehp_isr() does not count how many times each event occurred, but
merely records the fact *that* an event occurred.  If the same event
occurs a second time before pciehp_ist() is woken, that second event
will not be recorded separately, which is problematic according to
commit fad214b0 ("PCI: pciehp: Process all hotplug events before
looking for new ones") because we may miss removal of a card in-between
two back-to-back insertions.  We're about to make pciehp_ist() resilient
to missed events.  The present commit regresses the driver's behavior
temporarily in order to separate the changes into reviewable chunks.
This doesn't affect regular slow-motion hotplug, only plug-unplug-plug
operations that happen in a timespan shorter than wakeup of the IRQ
thread.
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Mayurkumar Patel <mayurkumar.patel@intel.com>
Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
      7b4ce26b
    • L
      PCI: pciehp: Document struct slot and struct controller · 4aed1cd6
      由 Lukas Wunner 提交于 
      Document the driver's data structures to lower the barrier to entry for
contributors.
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
      4aed1cd6
    • L
      PCI: pciehp: Declare pciehp_unconfigure_device() void · 1d2e2673
      由 Lukas Wunner 提交于 
      Since commit 0f4bd801 ("PCI: hotplug: Drop checking of PCI_BRIDGE_
CONTROL in *_unconfigure_device()"), pciehp_unconfigure_device() can no
longer fail, so declare it and its sole caller remove_board() void, in
keeping with the usual kernel pattern that enablement can fail, but
disablement cannot.  No functional change intended.
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
      1d2e2673
    • L
      PCI: pciehp: Drop unnecessary NULL pointer check · 6641311d
      由 Lukas Wunner 提交于 
      pciehp_disable_slot() checks if the ctrl attribute of the slot is NULL
and bails out if so.  However the function is not called prior to the
attribute being set in pcie_init_slot(), and pcie_init_slot() is not
called if ctrl is NULL.  So the check is unnecessary.  Drop it.

It has been present ever since the driver was introduced in 2004, but it
was already unnecessary back then:
https://git.kernel.org/tglx/history/c/c16b4b14d980Signed-off-by: NLukas Wunner <lukas@wunner.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
      6641311d
    • L
      PCI: pciehp: Fix unprotected list iteration in IRQ handler · 1204e35b
      由 Lukas Wunner 提交于 
      Commit b440bde7 ("PCI: Add pci_ignore_hotplug() to ignore hotplug
events for a device") iterates over the devices on a hotplug port's
subordinate bus in pciehp's IRQ handler without acquiring pci_bus_sem.
It is thus possible for a user to cause a crash by concurrently
manipulating the device list, e.g. by disabling slot power via sysfs
on a different CPU or by initiating a remove/rescan via sysfs.

This can't be fixed by acquiring pci_bus_sem because it may sleep.
The simplest fix is to avoid the list iteration altogether and just
check the ignore_hotplug flag on the port itself.  This works because
pci_ignore_hotplug() sets the flag both on the device as well as on its
parent bridge.

We do lose the ability to print the name of the device blocking hotplug
in the debug message, but that's probably bearable.

Fixes: b440bde7 ("PCI: Add pci_ignore_hotplug() to ignore hotplug events for a device")
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org
      1204e35b
    • L
      PCI: pciehp: Fix use-after-free on unplug · 281e878e
      由 Lukas Wunner 提交于 
      When pciehp is unbound (e.g. on unplug of a Thunderbolt device), the
hotplug_slot struct is deregistered and thus freed before freeing the
IRQ.  The IRQ handler and the work items it schedules print the slot
name referenced from the freed structure in various informational and
debug log messages, each time resulting in a quadruple dereference of
freed pointers (hotplug_slot -> pci_slot -> kobject -> name).

At best the slot name is logged as "(null)", at worst kernel memory is
exposed in logs or the driver crashes:

  pciehp 0000:10:00.0:pcie204: Slot((null)): Card not present

An attacker may provoke the bug by unplugging multiple devices on a
Thunderbolt daisy chain at once.  Unplugging can also be simulated by
powering down slots via sysfs.  The bug is particularly easy to trigger
in poll mode.

It has been present since the driver's introduction in 2004:
https://git.kernel.org/tglx/history/c/c16b4b14d980

Fix by rearranging teardown such that the IRQ is freed first.  Run the
work items queued by the IRQ handler to completion before freeing the
hotplug_slot struct by draining the work queue from the ->release_slot
callback which is invoked by pci_hp_deregister().
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org # v2.6.4
      281e878e
    • L
      PCI: hotplug: Don't leak pci_slot on registration failure · 4ce64358
      由 Lukas Wunner 提交于 
      If addition of sysfs files fails on registration of a hotplug slot, the
struct pci_slot as well as the entry in the slot_list is leaked.  The
issue has been present since the hotplug core was introduced in 2002:
https://git.kernel.org/tglx/history/c/a8a2069f432c

Perhaps the idea was that even though sysfs addition fails, the slot
should still be usable.  But that's not how drivers use the interface,
they abort probe if a non-zero value is returned.
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org # v2.4.15+
Cc: Greg Kroah-Hartman <greg@kroah.com>
      4ce64358
    • L
      PCI: hotplug: Delete skeleton driver · b4efce5c
      由 Lukas Wunner 提交于 
      Ten years ago, commit 58319b80 ("PCI: Hotplug core: remove 'name'")
dropped the name element from struct hotplug_slot but neglected to update
the skeleton driver.

That same year, commit f46753c5 ("PCI: introduce pci_slot") raised the
number of arguments to pci_hp_register() from one to four.

Fourteen years ago, historic commit 7ab60fc1b8e7 ("PCI Hotplug skeleton:
final cleanups") removed all usages of the retval variable from
pcihp_skel_init() but not the variable itself, provoking a compiler
warning: https://git.kernel.org/tglx/history/c/7ab60fc1b8e7

It seems fair to assume the driver hasn't been used as a template for a new
driver in a while.  Per Bjorn's and Christoph's preference, delete it.
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Cc: Christoph Hellwig <hch@lst.de>
      b4efce5c
  3. 27 6月, 2018 1 次提交
    • B
      PCI: shpchp: Separate existence of SHPC and permission to use it · b03799b0
      由 Bjorn Helgaas 提交于 
      The shpchp driver registers for all PCI bridge devices.  Its probe method
should fail if either (1) the bridge doesn't have an SHPC or (2) the OS
isn't allowed to use it (the platform firmware may be operating the SHPC
itself).

Separate these two tests into:

  - A new shpc_capable() that looks for the SHPC hardware and is applicable
    on all systems (ACPI and non-ACPI), and

  - A simplified acpi_get_hp_hw_control_from_firmware() that we call only
    when we already know an SHPC exists and there may be ACPI methods to
    either request permission to use it (_OSC) or transfer control to the
    OS (OSHP).

acpi_get_hp_hw_control_from_firmware() is implemented when CONFIG_ACPI=y,
but does nothing if the current platform doesn't support ACPI.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>
      b03799b0
  5. 26 6月, 2018 1 次提交
  7. 05 6月, 2018 5 次提交
  9. 02 6月, 2018 5 次提交
  11. 24 5月, 2018 2 次提交
  13. 18 5月, 2018 1 次提交
  15. 08 5月, 2018 1 次提交
    • B
      PCI: pciehp: Add quirk for Command Completed errata · d22b3621
      由 Bjorn Helgaas 提交于 
      Several PCIe hotplug controllers have errata that mean they do not set the
Command Completed bit unless writes to the Slot Command register change
"Control" bits.  Command Completed is never set for writes that only change
software notification "Enable" bits.  This results in timeouts like this:

  pciehp 0000:00:1c.0:pcie004: Timeout on hotplug command 0x1038 (issued 65284 msec ago)

When this erratum is present, avoid these timeouts by marking commands
"completed" immediately unless they change the "Control" bits.

Here's the text of the Intel erratum CF118.  We assume this applies to all
Intel parts:

  CF118        PCIe Slot Status Register Command Completed bit not always
               updated on any configuration write to the Slot Control
               Register

  Problem:     For PCIe root ports (devices 0 - 10) supporting hot-plug,
               the Slot Status Register (offset AAh) Command Completed
               (bit[4]) status is updated under the following condition:
               IOH will set Command Completed bit after delivering the new
               commands written in the Slot Controller register (offset
               A8h) to VPP. The IOH detects new commands written in Slot
               Control register by checking the change of value for Power
               Controller Control (bit[10]), Power Indicator Control
               (bits[9:8]), Attention Indicator Control (bits[7:6]), or
               Electromechanical Interlock Control (bit[11]) fields. Any
               other configuration writes to the Slot Control register
               without changing the values of these fields will not cause
               Command Completed bit to be set.

               The PCIe Base Specification Revision 2.0 or later describes
               the “Slot Control Register” in section 7.8.10, as follows
               (Reference section 7.8.10, Slot Control Register, Offset
               18h). In hot-plug capable Downstream Ports, a write to the
               Slot Control register must cause a hot-plug command to be
               generated (see Section 6.7.3.2 for details on hot-plug
               commands). A write to the Slot Control register in a
               Downstream Port that is not hotplug capable must not cause a
               hot-plug command to be executed.

               The PCIe Spec intended that every write to the Slot Control
               Register is a command and expected a command complete status
               to abstract the VPP implementation specific nuances from the
               OS software. IOH PCIe Slot Control Register implementation
               is not fully conforming to the PCIe Specification in this
               respect.

  Implication: Software checking on the Command Completed status after
               writing to the Slot Control register may time out.

  Workaround:  Software can read the Slot Control register and compare the
               existing and new values to determine if it should check the
               Command Completed status after writing to the Slot Control
               register.

Per Sinan, the Qualcomm QDF2400 controller also does not set the Command
Completed bit unless writes to the Slot Command register change "Control"
bits.

Link: http://www.intel.com/content/www/us/en/processors/xeon/xeon-e7-v2-spec-update.html
Link: https://lkml.kernel.org/r/8770820b-85a0-172b-7230-3a44524e6c9f@molgen.mpg.de
Reported-by: Paul Menzel <pmenzel+linux-pci@molgen.mpg.de>	# Lenovo X60
Tested-by: Paul Menzel <pmenzel+linux-pci@molgen.mpg.de>	# Lenovo X60
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>		# Qcom quirk
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>
      d22b3621
  17. 21 4月, 2018 1 次提交
  19. 24 3月, 2018 1 次提交
    • M
      ACPI / hotplug / PCI: Check presence of slot itself in get_slot_status() · 13d3047c
      由 Mika Westerberg 提交于 
      Mike Lothian reported that plugging in a USB-C device does not work
properly in his Dell Alienware system.  This system has an Intel Alpine
Ridge Thunderbolt controller providing USB-C functionality.  In these
systems the USB controller (xHCI) is hotplugged whenever a device is
connected to the port using ACPI-based hotplug.

The ACPI description of the root port in question is as follows:

  Device (RP01)
  {
      Name (_ADR, 0x001C0000)

      Device (PXSX)
      {
          Name (_ADR, 0x02)

          Method (_RMV, 0, NotSerialized)
          {
              // ...
          }
      }

Here _ADR 0x02 means device 0, function 2 on the bus under root port (RP01)
but that seems to be incorrect because device 0 is the upstream port of the
Alpine Ridge PCIe switch and it has no functions other than 0 (the bridge
itself).  When we get ACPI Notify() to the root port resulting from
connecting a USB-C device, Linux tries to read PCI_VENDOR_ID from device 0,
function 2 which of course always returns 0xffffffff because there is no
such function and we never find the device.

In Windows this works fine.

Now, since we get ACPI Notify() to the root port and not to the PXSX device
we should actually start our scan from there as well and not from the
non-existent PXSX device.  Fix this by checking presence of the slot itself
(function 0) if we fail to do that otherwise.

While there use pci_bus_read_dev_vendor_id() in get_slot_status(), which is
the recommended way to read Device and Vendor IDs of devices on PCI buses.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=198557Reported-by: NMike Lothian <mike@fireburn.co.uk>
Signed-off-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org
      13d3047c
  21. 13 3月, 2018 1 次提交
  23. 10 3月, 2018 1 次提交
  25. 01 3月, 2018 1 次提交
  27. 23 2月, 2018 1 次提交
  29. 04 2月, 2018 1 次提交
  31. 30 1月, 2018 1 次提交
  33. 29 1月, 2018 2 次提交
  35. 27 1月, 2018 1 次提交
  37. 24 1月, 2018 1 次提交
    • L
      PCI: pciehp: Assume NoCompl+ for Thunderbolt ports · 493fb50e
      由 Lukas Wunner 提交于 
      Certain Thunderbolt 1 controllers claim to support Command Completed events
(value of 0b in the No Command Completed Support field of the Slot
Capabilities register) but in reality they neither set the Command
Completed bit in the Slot Status register nor signal a Command Completed
interrupt:

  8086:1513  CV82524  [Light Ridge 4C  2010]
  8086:151a  DSL2310  [Eagle Ridge 2C  2011]
  8086:151b  CVL2510  [Light Peak 2C   2010]
  8086:1547  DSL3510  [Cactus Ridge 4C 2012]
  8086:1548  DSL3310  [Cactus Ridge 2C 2012]
  8086:1549  DSL2210  [Port Ridge 1C   2011]

All known newer chips (Redwood Ridge and onwards) set No Command Completed
Support, indicating that they do not support Command Completed events.

The user-visible impact is that after unplugging such a device, 2 seconds
elapse until pciehp is unbound.  That's because on ->remove,
pcie_write_cmd() is called via pcie_disable_notification() and every call
to pcie_write_cmd() takes 2 seconds (1 second for each invocation of
pcie_wait_cmd()):

  [  337.942727] pciehp 0000:0a:00.0:pcie204: Timeout on hotplug command 0x1038 (issued 21176 msec ago)
  [  340.014735] pciehp 0000:0a:00.0:pcie204: Timeout on hotplug command 0x0000 (issued 2072 msec ago)

That by itself has always been unpleasant, but the situation has become
worse with commit cc27b735 ("PCI/portdrv: Turn off PCIe services during
shutdown"):  Now pciehp is unbound on ->shutdown.  Because Thunderbolt
controllers typically have 4 hotplug ports, every reboot and shutdown is
now delayed by 8 seconds, plus another 2 seconds for every attached
Thunderbolt 1 device.

Thunderbolt hotplug slots are not physical slots that one inserts cards
into, but rather logical hotplug slots implemented in silicon.  Devices
appear beyond those logical slots once a PCI tunnel is established on top
of the Thunderbolt Converged I/O switch.  One would expect commands written
to the Slot Control register to be executed immediately by the silicon, so
for simplicity we always assume NoCompl+ for Thunderbolt ports.

Fixes: cc27b735 ("PCI/portdrv: Turn off PCIe services during shutdown")
Tested-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Cc: stable@vger.kernel.org	# v4.12+
Cc: Sinan Kaya <okaya@codeaurora.org>
Cc: Yehezkel Bernat <yehezkel.bernat@intel.com>
Cc: Michael Jamet <michael.jamet@intel.com>
Cc: Andreas Noever <andreas.noever@gmail.com>
      493fb50e
  39. 21 1月, 2018 1 次提交
    • M
      hotplug/drc-info: Add code to search ibm,drc-info property · 2fcf3ae5
      由 Michael Bringmann 提交于 
      rpadlpar_core.c: Provide parallel routines to search the older device-
tree properties ("ibm,drc-indexes", "ibm,drc-names", "ibm,drc-types"
and "ibm,drc-power-domains"), or the new property "ibm,drc-info".

The interface to examine the DRC information is changed from a "get"
function that returns values for local verification elsewhere, to a
"check" function that validates the 'name' and/or 'type' of a device
node.  This update hides the format of the underlying device-tree
properties, and concentrates the value checks into a single function
without requiring the user to verify whether a search was successful.
Signed-off-by: NMichael Bringmann <mwb@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      2fcf3ae5