Commit Graph

1291 Commits

Author SHA1 Message Date
Frederick Lawler 742ee16bc3 PCI: pciehp: Remove unused dbg/err/info/warn() wrappers
Replace the last uses of dbg() with the equivalent pr_debug(), then remove
unused dbg(), err(), info(), and warn() wrappers.

Link: https://lore.kernel.org/lkml/20190509141456.223614-9-helgaas@kernel.org
Signed-off-by: Frederick Lawler <fred@fredlawl.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
2019-05-09 16:45:20 -05:00
Frederick Lawler 94dbc9562e PCI: pciehp: Log messages with pci_dev, not pcie_device
Log messages with pci_dev, not pcie_device.  Factor out common message
prefixes with dev_fmt().

Example output change:

  - pciehp 0000:00:06.0:pcie004: Slot(0) Powering on due to button press
  + pcieport 0000:00:06.0: pciehp: Slot(0) Powering on due to button press

Link: https://lore.kernel.org/lkml/20190509141456.223614-8-helgaas@kernel.org
Signed-off-by: Frederick Lawler <fred@fredlawl.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
2019-05-09 16:45:20 -05:00
Frederick Lawler 017124725c PCI: pciehp: Replace pciehp_debug module param with dyndbg
Previously pciehp debug messages were enabled by the pciehp_debug module
parameter, e.g., by booting with this kernel command line option:

  pciehp.pciehp_debug=1

Convert this mechanism to use the generic dynamic debug (dyndbg) feature.
After this commit, pciehp debug messages are enabled by building the kernel
with CONFIG_DYNAMIC_DEBUG=y and booting with this command line option:

  dyndbg="file pciehp* +p"

The dyndbg facility is much more flexible: messages can be enabled at boot-
or run-time based on the file name, function name, line number, message
test, etc.  See Documentation/admin-guide/dynamic-debug-howto.rst for more
details.

Link: https://lore.kernel.org/lkml/20190509141456.223614-7-helgaas@kernel.org
Signed-off-by: Frederick Lawler <fred@fredlawl.com>
[bhelgaas: commit log, comment, remove pciehp_debug parameter]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
2019-05-09 16:45:20 -05:00
Bjorn Helgaas 7e696b8ae9 PCI: pciehp: Remove pciehp_debug uses
We're about to convert pciehp to the dyndbg mechanism, which means we can
eventually remove pciehp_debug.

Replace uses of pciehp_debug with dbg() and ctrl_dbg(), which check
pciehp_debug internally.

Link: https://lore.kernel.org/lkml/20190509141456.223614-6-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
2019-05-09 16:45:19 -05:00
Tyrel Datwyler 91800660bb PCI: rpaphp: Get/put device node reference during slot alloc/dealloc
When allocating the slot structure we store a pointer to the associated
device_node.  We really should be incrementing the reference count, so add
an of_node_get() during slot alloc and an of_node_put() during slot
dealloc.

Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2019-04-10 16:07:12 -05:00
Tyrel Datwyler fb26228bfc PCI: rpadlpar: Fix leaked device_node references in add/remove paths
The find_dlpar_node() helper returns a device node with its reference
incremented.  Both the add and remove paths use this helper for find the
appropriate node, but fail to release the reference when done.

Annotate the find_dlpar_node() helper with a comment about the incremented
reference count and call of_node_put() on the obtained device_node in the
add and remove paths.  Also, fixup a reference leak in the find_vio_slot()
helper where we fail to call of_node_put() on the vdevice node after we
iterate over its children.

Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2019-04-10 16:07:12 -05:00
Sergey Miroshnichenko 3943af9d01 PCI: pciehp: Ignore Link State Changes after powering off a slot
During a safe hot remove, the OS powers off the slot, which may cause a
Data Link Layer State Changed event.  The slot has already been set to
OFF_STATE, so that event results in re-enabling the device, making it
impossible to safely remove it.

Clear out the Presence Detect Changed and Data Link Layer State Changed
events when the disabled slot has settled down.

It is still possible to re-enable the device if it remains in the slot
after pressing the Attention Button by pressing it again.

Fixes the problem that Micah reported below: an NVMe drive power button may
not actually turn off the drive.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=203237
Reported-by: Micah Parrish <micah.parrish@hpe.com>
Tested-by: Micah Parrish <micah.parrish@hpe.com>
Signed-off-by: Sergey Miroshnichenko <s.miroshnichenko@yadro.com>
[bhelgaas: changelog, add bugzilla URL]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org	# v4.19+
2019-04-10 16:06:43 -05:00
Bjorn Helgaas 7733f69288 Merge branch 'pci/pm'
- Blacklist Gigabyte X299 Root Port power management to fix Thunderbolt
    hotplug (Mika Westerberg)

  - Revert runtime PM suspend/resume callbacks that broke PME on network
    cable plug (Mika Westerberg)

  - Disable Data Link State Changed interrupts to prevent wakeup
    immediately after suspend (Mika Westerberg)

* pci/pm:
  PCI/PME: Fix possible use-after-free on remove
  PCI/PME: Fix hotplug/sysfs remove deadlock in pcie_pme_remove()
  PCI: pciehp: Disable Data Link Layer State Changed event on suspend
  Revert "PCI/PME: Implement runtime PM callbacks"
  PCI: Blacklist power management of Gigabyte X299 DESIGNARE EX PCIe ports
2019-03-06 15:30:15 -06:00
Bjorn Helgaas 6d940a71c9 Merge branch 'pci/misc'
- Mark expected switch fall-through (Mathieu Malaterre)

  - Use of_node_name_eq() for node name comparisons (Rob Herring)

  - Add ACS and pciehp quirks for HXT SD4800 (Shunyong Yang)

  - Consolidate Rohm Vendor ID definitions (Andy Shevchenko)

  - Use u32 (not __u32) for things not exposed to userspace (Logan
    Gunthorpe)

  - Fix locking semantics of bus and slot reset interfaces (Alex
    Williamson)

  - Update PCIEPORTBUS Kconfig help text (Hou Zhiqiang)

* pci/misc:
  PCI: Update PCIEPORTBUS Kconfig help text
  PCI: Fix "try" semantics of bus and slot reset
  PCI: Clean up usage of __u32 type
  genirq/msi: Clean up usage of __u8/__u16 types
  PCI: Move Rohm Vendor ID to generic list
  PCI: pciehp: Add HXT quirk for Command Completed errata
  PCI: Add ACS quirk for HXT SD4800
  PCI: Add HXT vendor ID
  PCI: Use of_node_name_eq() for node name comparisons
  PCI: Mark expected switch fall-through
2019-03-06 15:30:13 -06:00
Mika Westerberg bbe54ea533 PCI: pciehp: Disable Data Link Layer State Changed event on suspend
Commit 0e157e5286 ("PCI/PME: Implement runtime PM callbacks") tried to
solve an issue where the hierarchy immediately wakes up when it is
transitioned into D3cold.  However, it turns out to prevent PME
propagation on some systems that do not support D3cold.

I looked more closely at what might cause the immediate wakeup.  It happens
when the ACPI power resource of the root port is turned off.  The AML code
associated with the _OFF() method of the ACPI power resource starts a PCIe
L2/L3 Ready transition and waits for it to complete.  Right after the L2/L3
Ready transition is started the root port receives a PME from the
downstream port.

The simplest hierarchy where this happens looks like this:

  00:1d.0 PCIe Root Port
    ^
    |
    v
    05:00.0 PCIe switch #1 upstream port
      06:01.0 PCIe switch #1 downstream hotplug port
        ^
        |
        v
        08:00.0 PCIe switch #2 upstream port

It seems that the PCIe link between the two switches, before
PME_Turn_Off/PME_TO_Ack is complete for the whole hierarchy, goes
inactive and triggers PME towards the root port bringing it back to D0.
The L2/L3 Ready sequence is described in PCIe r4.0 spec sections 5.2 and
5.3.3 but unfortunately they do not state what happens if DLLSCE is
enabled during the sequence.

Disabling Data Link Layer State Changed event (DLLSCE) seems to prevent
the issue and still allows the downstream hotplug port to notice when a
device is plugged/unplugged.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=202593
Fixes: 0e157e5286 ("PCI/PME: Implement runtime PM callbacks")
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
CC: stable@vger.kernel.org	# v4.20+
2019-02-15 14:18:00 -06:00
Shunyong Yang 22e4d639cd PCI: pciehp: Add HXT quirk for Command Completed errata
The HXT SD4800 PCI controller does not set the Command Completed bit unless
writes to the Slot Command register change "Control" bits.

Add SD4800 to the quirk.

Signed-off-by: Shunyong Yang <shunyong.yang@hxt-semitech.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Joey Zheng <yu.zheng@hxt-semitech.com>
2019-02-01 17:15:58 -06:00
Arnd Bergmann 2a727f6091 PCI: ibmphp: Turn semaphores into completions or mutexes
The sem_exit variable is conceptually a completion, so it should be called
that.

Similarly, the semOperations semaphore is a simple mutex, and can be
changed into that, respectively.

With both converted, the ibmphp_hpc_initvars() function is no longer used
and can be removed.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2019-01-29 17:15:36 -06:00
Mika Westerberg 25bd879ec1 PCI: pciehp: Assign ctrl->slot_ctrl before writing it to hardware
Shameerali reported that running v4.20-rc1 as QEMU guest, the PCIe hotplug
port times out during boot:

  pciehp 0000:00:01.0:pcie004: Timeout on hotplug command 0x03f1 (issued 1016 msec ago)
  pciehp 0000:00:01.0:pcie004: Timeout on hotplug command 0x03f1 (issued 1024 msec ago)
  pciehp 0000:00:01.0:pcie004: Failed to check link status
  pciehp 0000:00:01.0:pcie004: Timeout on hotplug command 0x02f1 (issued 2520 msec ago)

The issue was bisected down to commit 720d6a671a ("PCI: pciehp: Do not
handle events if interrupts are masked") and was further analyzed by the
reporter to be caused by the fact that pciehp first updates the hardware
and only then cache the ctrl->slot_ctrl in pcie_do_write_cmd().  If the
interrupt happens before we cache the value, pciehp_isr() reads value 0 and
decides that the interrupt was not meant for it causing the above timeout
to trigger.

Fix by moving ctrl->slot_ctrl assignment to happen before it is written to
the hardware.

Fixes: 720d6a671a ("PCI: pciehp: Do not handle events if interrupts are masked")
Link: https://lore.kernel.org/linux-pci/5FC3163CFD30C246ABAA99954A238FA8387DD344@FRAEML521-MBX.china.huawei.com
Reported-by: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2019-01-14 17:06:57 -06:00
Linus Torvalds dad4f140ed Merge branch 'xarray' of git://git.infradead.org/users/willy/linux-dax
Pull XArray conversion from Matthew Wilcox:
 "The XArray provides an improved interface to the radix tree data
  structure, providing locking as part of the API, specifying GFP flags
  at allocation time, eliminating preloading, less re-walking the tree,
  more efficient iterations and not exposing RCU-protected pointers to
  its users.

  This patch set

   1. Introduces the XArray implementation

   2. Converts the pagecache to use it

   3. Converts memremap to use it

  The page cache is the most complex and important user of the radix
  tree, so converting it was most important. Converting the memremap
  code removes the only other user of the multiorder code, which allows
  us to remove the radix tree code that supported it.

  I have 40+ followup patches to convert many other users of the radix
  tree over to the XArray, but I'd like to get this part in first. The
  other conversions haven't been in linux-next and aren't suitable for
  applying yet, but you can see them in the xarray-conv branch if you're
  interested"

* 'xarray' of git://git.infradead.org/users/willy/linux-dax: (90 commits)
  radix tree: Remove multiorder support
  radix tree test: Convert multiorder tests to XArray
  radix tree tests: Convert item_delete_rcu to XArray
  radix tree tests: Convert item_kill_tree to XArray
  radix tree tests: Move item_insert_order
  radix tree test suite: Remove multiorder benchmarking
  radix tree test suite: Remove __item_insert
  memremap: Convert to XArray
  xarray: Add range store functionality
  xarray: Move multiorder_check to in-kernel tests
  xarray: Move multiorder_shrink to kernel tests
  xarray: Move multiorder account test in-kernel
  radix tree test suite: Convert iteration test to XArray
  radix tree test suite: Convert tag_tagged_items to XArray
  radix tree: Remove radix_tree_clear_tags
  radix tree: Remove radix_tree_maybe_preload_order
  radix tree: Remove split/join code
  radix tree: Remove radix_tree_update_node_t
  page cache: Finish XArray conversion
  dax: Convert page fault handlers to XArray
  ...
2018-10-28 11:35:40 -07:00
Linus Torvalds 685f7e4f16 powerpc updates for 4.20
Notable changes:
 
  - A large series to rewrite our SLB miss handling, replacing a lot of fairly
    complicated asm with much fewer lines of C.
 
  - Following on from that, we now maintain a cache of SLB entries for each
    process and preload them on context switch. Leading to a 27% speedup for our
    context switch benchmark on Power9.
 
  - Improvements to our handling of SLB multi-hit errors. We now print more debug
    information when they occur, and try to continue running by flushing the SLB
    and reloading, rather than treating them as fatal.
 
  - Enable THP migration on 64-bit Book3S machines (eg. Power7/8/9).
 
  - Add support for physical memory up to 2PB in the linear mapping on 64-bit
    Book3S. We only support up to 512TB as regular system memory, otherwise the
    percpu allocator runs out of vmalloc space.
 
  - Add stack protector support for 32 and 64-bit, with a per-task canary.
 
  - Add support for PTRACE_SYSEMU and PTRACE_SYSEMU_SINGLESTEP.
 
  - Support recognising "big cores" on Power9, where two SMT4 cores are presented
    to us as a single SMT8 core.
 
  - A large series to cleanup some of our ioremap handling and PTE flags.
 
  - Add a driver for the PAPR SCM (storage class memory) interface, allowing
    guests to operate on SCM devices (acked by Dan).
 
  - Changes to our ftrace code to handle very large kernels, where we need to use
    a trampoline to get to ftrace_caller().
 
 Many other smaller enhancements and cleanups.
 
 Thanks to:
   Alan Modra, Alistair Popple, Aneesh Kumar K.V, Anton Blanchard, Aravinda
   Prasad, Bartlomiej Zolnierkiewicz, Benjamin Herrenschmidt, Breno Leitao,
   Cédric Le Goater, Christophe Leroy, Christophe Lombard, Dan Carpenter, Daniel
   Axtens, Finn Thain, Gautham R. Shenoy, Gustavo Romero, Haren Myneni, Hari
   Bathini, Jia Hongtao, Joel Stanley, John Allen, Laurent Dufour, Madhavan
   Srinivasan, Mahesh Salgaonkar, Mark Hairgrove, Masahiro Yamada, Michael
   Bringmann, Michael Neuling, Michal Suchanek, Murilo Opsfelder Araujo, Nathan
   Fontenot, Naveen N. Rao, Nicholas Piggin, Nick Desaulniers, Oliver O'Halloran,
   Paul Mackerras, Petr Vorel, Rashmica Gupta, Reza Arbab, Rob Herring, Sam
   Bobroff, Samuel Mendoza-Jonas, Scott Wood, Stan Johnson, Stephen Rothwell,
   Stewart Smith, Suraj Jitindar Singh, Tyrel Datwyler, Vaibhav Jain, Vasant
   Hegde, YueHaibing, zhong jiang,
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Merge tag 'powerpc-4.20-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:
 "Notable changes:

   - A large series to rewrite our SLB miss handling, replacing a lot of
     fairly complicated asm with much fewer lines of C.

   - Following on from that, we now maintain a cache of SLB entries for
     each process and preload them on context switch. Leading to a 27%
     speedup for our context switch benchmark on Power9.

   - Improvements to our handling of SLB multi-hit errors. We now print
     more debug information when they occur, and try to continue running
     by flushing the SLB and reloading, rather than treating them as
     fatal.

   - Enable THP migration on 64-bit Book3S machines (eg. Power7/8/9).

   - Add support for physical memory up to 2PB in the linear mapping on
     64-bit Book3S. We only support up to 512TB as regular system
     memory, otherwise the percpu allocator runs out of vmalloc space.

   - Add stack protector support for 32 and 64-bit, with a per-task
     canary.

   - Add support for PTRACE_SYSEMU and PTRACE_SYSEMU_SINGLESTEP.

   - Support recognising "big cores" on Power9, where two SMT4 cores are
     presented to us as a single SMT8 core.

   - A large series to cleanup some of our ioremap handling and PTE
     flags.

   - Add a driver for the PAPR SCM (storage class memory) interface,
     allowing guests to operate on SCM devices (acked by Dan).

   - Changes to our ftrace code to handle very large kernels, where we
     need to use a trampoline to get to ftrace_caller().

  And many other smaller enhancements and cleanups.

  Thanks to: Alan Modra, Alistair Popple, Aneesh Kumar K.V, Anton
  Blanchard, Aravinda Prasad, Bartlomiej Zolnierkiewicz, Benjamin
  Herrenschmidt, Breno Leitao, Cédric Le Goater, Christophe Leroy,
  Christophe Lombard, Dan Carpenter, Daniel Axtens, Finn Thain, Gautham
  R. Shenoy, Gustavo Romero, Haren Myneni, Hari Bathini, Jia Hongtao,
  Joel Stanley, John Allen, Laurent Dufour, Madhavan Srinivasan, Mahesh
  Salgaonkar, Mark Hairgrove, Masahiro Yamada, Michael Bringmann,
  Michael Neuling, Michal Suchanek, Murilo Opsfelder Araujo, Nathan
  Fontenot, Naveen N. Rao, Nicholas Piggin, Nick Desaulniers, Oliver
  O'Halloran, Paul Mackerras, Petr Vorel, Rashmica Gupta, Reza Arbab,
  Rob Herring, Sam Bobroff, Samuel Mendoza-Jonas, Scott Wood, Stan
  Johnson, Stephen Rothwell, Stewart Smith, Suraj Jitindar Singh, Tyrel
  Datwyler, Vaibhav Jain, Vasant Hegde, YueHaibing, zhong jiang"

* tag 'powerpc-4.20-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (221 commits)
  Revert "selftests/powerpc: Fix out-of-tree build errors"
  powerpc/msi: Fix compile error on mpc83xx
  powerpc: Fix stack protector crashes on CPU hotplug
  powerpc/traps: restore recoverability of machine_check interrupts
  powerpc/64/module: REL32 relocation range check
  powerpc/64s/radix: Fix radix__flush_tlb_collapsed_pmd double flushing pmd
  selftests/powerpc: Add a test of wild bctr
  powerpc/mm: Fix page table dump to work on Radix
  powerpc/mm/radix: Display if mappings are exec or not
  powerpc/mm/radix: Simplify split mapping logic
  powerpc/mm/radix: Remove the retry in the split mapping logic
  powerpc/mm/radix: Fix small page at boundary when splitting
  powerpc/mm/radix: Fix overuse of small pages in splitting logic
  powerpc/mm/radix: Fix off-by-one in split mapping logic
  powerpc/ftrace: Handle large kernel configs
  powerpc/mm: Fix WARN_ON with THP NUMA migration
  selftests/powerpc: Fix out-of-tree build errors
  powerpc/time: no steal_time when CONFIG_PPC_SPLPAR is not selected
  powerpc/time: Only set CONFIG_ARCH_HAS_SCALED_CPUTIME on PPC64
  powerpc/time: isolate scaled cputime accounting in dedicated functions.
  ...
2018-10-26 14:36:21 -07:00
Linus Torvalds bd6bf7c104 pci-v4.20-changes
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Merge tag 'pci-v4.20-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci

Pull PCI updates from Bjorn Helgaas:

 - Fix ASPM link_state teardown on removal (Lukas Wunner)

 - Fix misleading _OSC ASPM message (Sinan Kaya)

 - Make _OSC optional for PCI (Sinan Kaya)

 - Don't initialize ASPM link state when ACPI_FADT_NO_ASPM is set
   (Patrick Talbert)

 - Remove x86 and arm64 node-local allocation for host bridge structures
   (Punit Agrawal)

 - Pay attention to device-specific _PXM node values (Jonathan Cameron)

 - Support new Immediate Readiness bit (Felipe Balbi)

 - Differentiate between pciehp surprise and safe removal (Lukas Wunner)

 - Remove unnecessary pciehp includes (Lukas Wunner)

 - Drop pciehp hotplug_slot_ops wrappers (Lukas Wunner)

 - Tolerate PCIe Slot Presence Detect being hardwired to zero to
   workaround broken hardware, e.g., the Wilocity switch/wireless device
   (Lukas Wunner)

 - Unify pciehp controller & slot structs (Lukas Wunner)

 - Constify hotplug_slot_ops (Lukas Wunner)

 - Drop hotplug_slot_info (Lukas Wunner)

 - Embed hotplug_slot struct into users instead of allocating it
   separately (Lukas Wunner)

 - Initialize PCIe port service drivers directly instead of relying on
   initcall ordering (Keith Busch)

 - Restore PCI config state after a slot reset (Keith Busch)

 - Save/restore DPC config state along with other PCI config state
   (Keith Busch)

 - Reference count devices during AER handling to avoid race issue with
   concurrent hot removal (Keith Busch)

 - If an Upstream Port reports ERR_FATAL, don't try to read the Port's
   config space because it is probably unreachable (Keith Busch)

 - During error handling, use slot-specific reset instead of secondary
   bus reset to avoid link up/down issues on hotplug ports (Keith Busch)

 - Restore previous AER/DPC handling that does not remove and
   re-enumerate devices on ERR_FATAL (Keith Busch)

 - Notify all drivers that may be affected by error recovery resets
   (Keith Busch)

 - Always generate error recovery uevents, even if a driver doesn't have
   error callbacks (Keith Busch)

 - Make PCIe link active reporting detection generic (Keith Busch)

 - Support D3cold in PCIe hierarchies during system sleep and runtime,
   including hotplug and Thunderbolt ports (Mika Westerberg)

 - Handle hpmemsize/hpiosize kernel parameters uniformly, whether slots
   are empty or occupied (Jon Derrick)

 - Remove duplicated include from pci/pcie/err.c and unused variable
   from cpqphp (YueHaibing)

 - Remove driver pci_cleanup_aer_uncorrect_error_status() calls (Oza
   Pawandeep)

 - Uninline PCI bus accessors for better ftracing (Keith Busch)

 - Remove unused AER Root Port .error_resume method (Keith Busch)

 - Use kfifo in AER instead of a local version (Keith Busch)

 - Use threaded IRQ in AER bottom half (Keith Busch)

 - Use managed resources in AER core (Keith Busch)

 - Reuse pcie_port_find_device() for AER injection (Keith Busch)

 - Abstract AER interrupt handling to disconnect error injection (Keith
   Busch)

 - Refactor AER injection callbacks to simplify future improvments
   (Keith Busch)

 - Remove unused Netronome NFP32xx Device IDs (Jakub Kicinski)

 - Use bitmap_zalloc() for dma_alias_mask (Andy Shevchenko)

 - Add switch fall-through annotations (Gustavo A. R. Silva)

 - Remove unused Switchtec quirk variable (Joshua Abraham)

 - Fix pci.c kernel-doc warning (Randy Dunlap)

 - Remove trivial PCI wrappers for DMA APIs (Christoph Hellwig)

 - Add Intel GPU device IDs to spurious interrupt quirk (Bin Meng)

 - Run Switchtec DMA aliasing quirk only on NTB endpoints to avoid
   useless dmesg errors (Logan Gunthorpe)

 - Update Switchtec NTB documentation (Wesley Yung)

 - Remove redundant "default n" from Kconfig (Bartlomiej Zolnierkiewicz)

 - Avoid panic when drivers enable MSI/MSI-X twice (Tonghao Zhang)

 - Add PCI support for peer-to-peer DMA (Logan Gunthorpe)

 - Add sysfs group for PCI peer-to-peer memory statistics (Logan
   Gunthorpe)

 - Add PCI peer-to-peer DMA scatterlist mapping interface (Logan
   Gunthorpe)

 - Add PCI configfs/sysfs helpers for use by peer-to-peer users (Logan
   Gunthorpe)

 - Add PCI peer-to-peer DMA driver writer's documentation (Logan
   Gunthorpe)

 - Add block layer flag to indicate driver support for PCI peer-to-peer
   DMA (Logan Gunthorpe)

 - Map Infiniband scatterlists for peer-to-peer DMA if they contain P2P
   memory (Logan Gunthorpe)

 - Register nvme-pci CMB buffer as PCI peer-to-peer memory (Logan
   Gunthorpe)

 - Add nvme-pci support for PCI peer-to-peer memory in requests (Logan
   Gunthorpe)

 - Use PCI peer-to-peer memory in nvme (Stephen Bates, Steve Wise,
   Christoph Hellwig, Logan Gunthorpe)

 - Cache VF config space size to optimize enumeration of many VFs
   (KarimAllah Ahmed)

 - Remove unnecessary <linux/pci-ats.h> include (Bjorn Helgaas)

 - Fix VMD AERSID quirk Device ID matching (Jon Derrick)

 - Fix Cadence PHY handling during probe (Alan Douglas)

 - Signal Cadence Endpoint interrupts via AXI region 0 instead of last
   region (Alan Douglas)

 - Write Cadence Endpoint MSI interrupts with 32 bits of data (Alan
   Douglas)

 - Remove redundant controller tests for "device_type == pci" (Rob
   Herring)

 - Document R-Car E3 (R8A77990) bindings (Tho Vu)

 - Add device tree support for R-Car r8a7744 (Biju Das)

 - Drop unused mvebu PCIe capability code (Thomas Petazzoni)

 - Add shared PCI bridge emulation code (Thomas Petazzoni)

 - Convert mvebu to use shared PCI bridge emulation (Thomas Petazzoni)

 - Add aardvark Root Port emulation (Thomas Petazzoni)

 - Support 100MHz/200MHz refclocks for i.MX6 (Lucas Stach)

 - Add initial power management for i.MX7 (Leonard Crestez)

 - Add PME_Turn_Off support for i.MX7 (Leonard Crestez)

 - Fix qcom runtime power management error handling (Bjorn Andersson)

 - Update TI dra7xx unaligned access errata workaround for host mode as
   well as endpoint mode (Vignesh R)

 - Fix kirin section mismatch warning (Nathan Chancellor)

 - Remove iproc PAXC slot check to allow VF support (Jitendra Bhivare)

 - Quirk Keystone K2G to limit MRRS to 256 (Kishon Vijay Abraham I)

 - Update Keystone to use MRRS quirk for host bridge instead of open
   coding (Kishon Vijay Abraham I)

 - Refactor Keystone link establishment (Kishon Vijay Abraham I)

 - Simplify and speed up Keystone link training (Kishon Vijay Abraham I)

 - Remove unused Keystone host_init argument (Kishon Vijay Abraham I)

 - Merge Keystone driver files into one (Kishon Vijay Abraham I)

 - Remove redundant Keystone platform_set_drvdata() (Kishon Vijay
   Abraham I)

 - Rename Keystone functions for uniformity (Kishon Vijay Abraham I)

 - Add Keystone device control module DT binding (Kishon Vijay Abraham
   I)

 - Use SYSCON API to get Keystone control module device IDs (Kishon
   Vijay Abraham I)

 - Clean up Keystone PHY handling (Kishon Vijay Abraham I)

 - Use runtime PM APIs to enable Keystone clock (Kishon Vijay Abraham I)

 - Clean up Keystone config space access checks (Kishon Vijay Abraham I)

 - Get Keystone outbound window count from DT (Kishon Vijay Abraham I)

 - Clean up Keystone outbound window configuration (Kishon Vijay Abraham
   I)

 - Clean up Keystone DBI setup (Kishon Vijay Abraham I)

 - Clean up Keystone ks_pcie_link_up() (Kishon Vijay Abraham I)

 - Fix Keystone IRQ status checking (Kishon Vijay Abraham I)

 - Add debug messages for all Keystone errors (Kishon Vijay Abraham I)

 - Clean up Keystone includes and macros (Kishon Vijay Abraham I)

 - Fix Mediatek unchecked return value from devm_pci_remap_iospace()
   (Gustavo A. R. Silva)

 - Fix Mediatek endpoint/port matching logic (Honghui Zhang)

 - Change Mediatek Root Port Class Code to PCI_CLASS_BRIDGE_PCI (Honghui
   Zhang)

 - Remove redundant Mediatek PM domain check (Honghui Zhang)

 - Convert Mediatek to pci_host_probe() (Honghui Zhang)

 - Fix Mediatek MSI enablement (Honghui Zhang)

 - Add Mediatek system PM support for MT2712 and MT7622 (Honghui Zhang)

 - Add Mediatek loadable module support (Honghui Zhang)

 - Detach VMD resources after stopping root bus to prevent orphan
   resources (Jon Derrick)

 - Convert pcitest build process to that used by other tools (iio, perf,
   etc) (Gustavo Pimentel)

* tag 'pci-v4.20-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (140 commits)
  PCI/AER: Refactor error injection fallbacks
  PCI/AER: Abstract AER interrupt handling
  PCI/AER: Reuse existing pcie_port_find_device() interface
  PCI/AER: Use managed resource allocations
  PCI: pcie: Remove redundant 'default n' from Kconfig
  PCI: aardvark: Implement emulated root PCI bridge config space
  PCI: mvebu: Convert to PCI emulated bridge config space
  PCI: mvebu: Drop unused PCI express capability code
  PCI: Introduce PCI bridge emulated config space common logic
  PCI: vmd: Detach resources after stopping root bus
  nvmet: Optionally use PCI P2P memory
  nvmet: Introduce helper functions to allocate and free request SGLs
  nvme-pci: Add support for P2P memory in requests
  nvme-pci: Use PCI p2pmem subsystem to manage the CMB
  IB/core: Ensure we map P2P memory correctly in rdma_rw_ctx_[init|destroy]()
  block: Add PCI P2P flag for request queue
  PCI/P2PDMA: Add P2P DMA driver writer's documentation
  docs-rst: Add a new directory for PCI documentation
  PCI/P2PDMA: Introduce configfs/sysfs enable attribute helpers
  PCI/P2PDMA: Add PCI p2pmem DMA mappings to adjust the bus offset
  ...
2018-10-25 06:50:48 -07:00
Sam Bobroff e762bb891a powerpc/eeh: Cleanup eeh_pe_state_mark()
Currently, eeh_pe_state_mark() marks a PE (and it's children) with a
state and then performs additional processing if that state included
EEH_PE_ISOLATED.

The state parameter is always a constant at the call site, so
rearrange eeh_pe_state_mark() into two functions and just call the
appropriate one at each site.

Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-10-13 22:21:25 +11:00
YueHaibing 74171e9dab PCI: pnv_php: Use kmemdup()
Use kmemdup() rather than duplicating its implementation.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
2018-10-02 16:04:40 -05:00
YueHaibing 37f1c5868e PCI: cpqphp: Remove set but not used variable 'physical_slot'
Fixes gcc '-Wunused-but-set-variable' warning:

  drivers/pci/hotplug/cpqphp_core.c: In function 'init_SERR':
  drivers/pci/hotplug/cpqphp_core.c:124:5: warning: variable 'physical_slot' set but not used [-Wunused-but-set-variable]

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-10-02 16:04:40 -05:00
Mika Westerberg 9c62f0bfb8 PCI: pciehp: Implement runtime PM callbacks
Basically we need to do the same thing when runtime suspending than with
system sleep so re-use those operations here. This makes sure hotplug
interrupt does not trigger immediately when the link goes down.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-10-02 16:04:40 -05:00
Mika Westerberg 720d6a671a PCI: pciehp: Do not handle events if interrupts are masked
PCIe native hotplug shares MSI vector with native PME so the interrupt
handler might get called even the hotplug interrupt is masked. In that case
we should not handle any events because the interrupt was not meant for us.

Modify the PCIe hotplug interrupt handler to check this accordingly and
bail out if it finds out that the interrupt was not about hotplug.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
2018-10-02 16:04:40 -05:00
Mika Westerberg eb34da60ed PCI: pciehp: Disable hotplug interrupt during suspend
When PCIe hotplug port is transitioned into D3hot, the link to the
downstream component will go down. If hotplug interrupt generation is
enabled when that happens, it will trigger immediately, waking up the
system and bringing the link back up.

To prevent this, disable hotplug interrupt generation when system suspend
is entered. This does not prevent wakeup from low power states according
to PCIe 4.0 spec section 6.7.3.4:

  Software enables a hot-plug event to generate a wakeup event by
  enabling software notification of the event as described in Section
  6.7.3.1. Note that in order for software to disable interrupt generation
  while keeping wakeup generation enabled, the Hot-Plug Interrupt Enable
  bit must be cleared.

So as long as we have set the slot event mask accordingly, wakeup should
work even if slot interrupt is disabled. The port should trigger wake and
then send PME to the root port when the PCIe hierarchy is brought back up.

Limit this to systems using native PME mechanism to make sure older Apple
systems depending on commit e3354628c376 ("PCI: pciehp: Support interrupts
sent from D3hot") still continue working.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-10-02 16:04:40 -05:00
Keith Busch f0157160b3 PCI: Make link active reporting detection generic
The spec has timing requirements when waiting for a link to become active
after a conventional reset.  Implement those hard delays when waiting for
an active link so pciehp and dpc drivers don't need to duplicate this.

For devices that don't support data link layer active reporting, wait the
fixed time recommended by the PCIe spec.

Signed-off-by: Keith Busch <keith.busch@intel.com>
[bhelgaas: changelog]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Sinan Kaya <okaya@kernel.org>
2018-10-02 16:04:40 -05:00
Matthew Wilcox 3d0186bb06 Update email address
Redirect some older email addresses that are in the git logs.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-09-29 22:47:48 -04:00
Mika Westerberg f188b99f0b ACPI / hotplug / PCI: Don't scan for non-hotplug bridges if slot is not bridge
HP 6730b laptop has an ethernet NIC connected to one of the PCIe root
ports.  The root ports themselves are native PCIe hotplug capable.  Now,
during boot after PCI devices are scanned the BIOS triggers ACPI bus check
directly to the NIC:

  ACPI: \_SB_.PCI0.RP06.NIC_: Bus check in hotplug_event()

It is not clear why it is sending bus check but regardless the ACPI hotplug
notify handler calls enable_slot() directly (instead of going through
acpiphp_check_bridge() as there is no bridge), which ends up handling
special case for non-hotplug bridges with native PCIe hotplug.  This
results a crash of some kind but the reporter only sees black screen so it
is hard to figure out the exact spot and what actually happens.  Based on
a few fix proposals it was tracked to crash somewhere inside
pci_assign_unassigned_bridge_resources().

In any case we should not really be in that special branch at all because
the ACPI notify happened to a slot that is not a PCI bridge (it is just a
regular PCI device).

Fix this so that we only go to that special branch if we are calling
enable_slot() for a bridge (e.g., the ACPI notification was for the
bridge).

Link: https://bugzilla.kernel.org/show_bug.cgi?id=201127
Fixes: 84c8b58ed3 ("ACPI / hotplug / PCI: Don't scan bridges managed by native hotplug")
Reported-by: Peter Anemone <peter.anemone@gmail.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
CC: stable@vger.kernel.org	# v4.18+
2018-09-26 15:39:28 -05:00
Keith Busch c29de84149 PCI: portdrv: Initialize service drivers directly
The PCI port driver saves the PCI state after initializing the device with
the applicable service devices.  This was, however, before the service
drivers were even registered because PCI probe happens before the
device_initcall initialized those service drivers.  The config space state
that the services set up were not being saved.  The end result would cause
PCI devices to not react to events that the drivers think they did if the
PCI state ever needed to be restored.

Fix this by changing the service drivers from using the init calls to
having the portdrv driver calling the services directly.  This will get the
state saved as desired, while making the relationship between the port
driver and the services under it more explicit in the code.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Sinan Kaya <okaya@kernel.org>
2018-09-20 12:05:54 -05:00
Lukas Wunner a0d5893740 PCI: hotplug: Document TODOs
While refactoring the PCI hotplug core's API, I noticed a significant
amount of technical debt in some of the hotplug drivers.  Document the
issues that caught my eye for starters.

I do not have hardware at my disposal that utilizes the listed drivers
and I think that's a prerequisite to work on them to ensure that no
regressions sneak in.  But some of this hardware is so old that it may be
hard to come by.  Obviously, it is fine to support old hardware, but the
drivers need to be maintained.

If noone steps up, perhaps we should consider sunsetting a few drivers
by moving them to staging.  Based on my findings, ibmphp would be the
first candidate.  I've found it fairly difficult to apply my API
refactorings to it and have listed some obvious bugs in the driver.
cpqphp is also in need of a modernization and would be a second
candidate for relegation to staging.

shpchp was introduced in the same commit as pciehp but hasn't benefited
from the same amount of refactoring due to the decline of conventional
PCI's relevance.  Yet hardware supporting it may be more prevalent than
for the proprietary hotplug methods.

Per Documentation/process/2.Process.rst, "a TODO file should be present"
for drivers in staging.  The file introduced by the present commit may
serve as a basis for this.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Scott Murray <scott@spiteful.org>
Cc: Dan Zink <dan.zink@hpe.com>
Cc: Prarit Bhargava <prarit@redhat.com>
2018-09-18 17:52:15 -05:00
Lukas Wunner 125450f814 PCI: hotplug: Embed hotplug_slot
When the PCI hotplug core and its first user, cpqphp, were introduced in
February 2002 with historic commit a8a2069f432c, cpqphp allocated a slot
struct for its internal use plus a hotplug_slot struct to be registered
with the hotplug core and linked the two with pointers:
https://git.kernel.org/tglx/history/c/a8a2069f432c

Nowadays, the predominant pattern in the tree is to embed ("subclass")
such structures in one another and cast to the containing struct with
container_of().  But it wasn't until July 2002 that container_of() was
introduced with historic commit ec4f214232cf:
https://git.kernel.org/tglx/history/c/ec4f214232cf

pnv_php, introduced in 2016, did the right thing and embedded struct
hotplug_slot in its internal struct pnv_php_slot, but all other drivers
cargo-culted cpqphp's design and linked separate structs with pointers.

Embedding structs is preferrable to linking them with pointers because
it requires fewer allocations, thereby reducing overhead and simplifying
error paths.  Casting an embedded struct to the containing struct
becomes a cheap subtraction rather than a dereference.  And having fewer
pointers reduces the risk of them pointing nowhere either accidentally
or due to an attack.

Convert all drivers to embed struct hotplug_slot in their internal slot
struct.  The "private" pointer in struct hotplug_slot thereby becomes
unused, so drop it.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>  # drivers/pci/hotplug/rpa*
Acked-by: Sebastian Ott <sebott@linux.ibm.com>        # drivers/pci/hotplug/s390*
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> # drivers/platform/x86
Cc: Len Brown <lenb@kernel.org>
Cc: Scott Murray <scott@spiteful.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Oliver OHalloran <oliveroh@au1.ibm.com>
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Corentin Chary <corentin.chary@gmail.com>
Cc: Darren Hart <dvhart@infradead.org>
2018-09-18 17:52:15 -05:00
Lukas Wunner a7da21613c PCI: hotplug: Drop hotplug_slot_info
Ever since the PCI hotplug core was introduced in 2002, drivers had to
allocate and register a struct hotplug_slot_info for every slot:
https://git.kernel.org/tglx/history/c/a8a2069f432c

Apparently the idea was that drivers furnish the hotplug core with an
up-to-date card presence status, power status, latch status and
attention indicator status as well as notify the hotplug core of changes
thereof.  However only 4 out of 12 hotplug drivers bother to notify the
hotplug core with pci_hp_change_slot_info() and the hotplug core never
made any use of the information:  There is just a single macro in
pci_hotplug_core.c, GET_STATUS(), which uses the hotplug_slot_info if
the driver lacks the corresponding callback in hotplug_slot_ops.  The
macro is called when the user reads the attribute via sysfs.

Now, if the callback isn't defined, the attribute isn't exposed in sysfs
in the first place (see e.g. has_power_file()).  There are only two
situations when the hotplug_slot_info would actually be accessed:

* If the driver defines ->enable_slot or ->disable_slot but not
  ->get_power_status.

* If the driver defines ->set_attention_status but not
  ->get_attention_status.

There is no driver doing the former and just a single driver doing the
latter, namely pnv_php.c.  Amend it with a ->get_attention_status
callback.  With that, the hotplug_slot_info becomes completely unused by
the PCI hotplug core.  But a few drivers use it internally as a cache:

cpcihp uses it to cache the latch_status and adapter_status.
cpqhp uses it to cache the adapter_status.
pnv_php and rpaphp use it to cache the attention_status.
shpchp uses it to cache all four values.

Amend these drivers to cache the information in their private slot
struct.  shpchp's slot struct already contains members to cache the
power_status and adapter_status, so additional members are only needed
for the other two values.  In the case of cpqphp, the cached value is
only accessed in a single place, so instead of caching it, read the
current value from the hardware.

Caution:  acpiphp, cpci, cpqhp, shpchp, asus-wmi and eeepc-laptop
populate the hotplug_slot_info with initial values on probe.  That code
is herewith removed.  There is a theoretical chance that the code has
side effects without which the driver fails to function, e.g. if the
ACPI method to read the adapter status needs to be executed at least
once on probe.  That seems unlikely to me, still maintainers should
review the changes carefully for this possibility.

Rafael adds: "I'm not aware of any case in which it will break anything,
[...] but if that happens, it may be necessary to add the execution of
the control methods in question directly to the initialization part."

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>  # drivers/pci/hotplug/rpa*
Acked-by: Sebastian Ott <sebott@linux.ibm.com>        # drivers/pci/hotplug/s390*
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> # drivers/platform/x86
Cc: Len Brown <lenb@kernel.org>
Cc: Scott Murray <scott@spiteful.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Oliver OHalloran <oliveroh@au1.ibm.com>
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Corentin Chary <corentin.chary@gmail.com>
Cc: Darren Hart <dvhart@infradead.org>
2018-09-18 17:52:15 -05:00
Lukas Wunner 81c4b5bf30 PCI: hotplug: Constify hotplug_slot_ops
Hotplug drivers cannot declare their hotplug_slot_ops const, making them
attractive targets for attackers, because upon registration of a hotplug
slot, __pci_hp_initialize() writes to the "owner" and "mod_name" members
in that struct.

Fix by moving these members to struct hotplug_slot and constify every
driver's hotplug_slot_ops except for pciehp.

pciehp constructs its hotplug_slot_ops at runtime based on the PCIe
port's capabilities, hence cannot declare them const.  It can be
converted to __write_rarely once that's mainlined:
http://www.openwall.com/lists/kernel-hardening/2016/11/16/3

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>  # drivers/pci/hotplug/rpa*
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> # drivers/platform/x86
Cc: Len Brown <lenb@kernel.org>
Cc: Scott Murray <scott@spiteful.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Oliver OHalloran <oliveroh@au1.ibm.com>
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Corentin Chary <corentin.chary@gmail.com>
Cc: Darren Hart <dvhart@infradead.org>
2018-09-18 17:52:15 -05:00
Lukas Wunner d758714235 PCI: pciehp: Reshuffle controller struct for clarity
The members in pciehp's controller struct are arranged in a seemingly
arbitrary order and have grown to an amount that I no longer consider
easily graspable by contributors.

Sort the members into 5 rubrics:
* Slot Capabilities register and quirks
* Slot Control register access
* Slot Status register event handling
* state machine
* hotplug core interface

Obviously, this is just my personal bikeshed color and if anyone has a
better idea, please come forward.  Any ordering will do as long as the
information is presented in a manageable manner.

No functional change intended.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-09-18 17:52:15 -05:00
Lukas Wunner 4ff3126e80 PCI: pciehp: Rename controller struct members for clarity
Of the members which were just moved from pciehp's slot struct to the
controller struct, rename "lock" to "state_lock" and rename "work" to
"button_work" for clarity.  Perform the rename separately to the
unification of the two structs per Sinan's request.

No functional change intended.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Sinan Kaya <okaya@kernel.org>
2018-09-18 17:52:15 -05:00
Lukas Wunner 5790a9c78e PCI: pciehp: Unify controller and slot structs
pciehp was originally introduced together with shpchp in a single
commit, c16b4b14d980 ("PCI Hotplug: Add SHPC and PCI Express hot-plug
drivers"):
https://git.kernel.org/tglx/history/c/c16b4b14d980

shpchp supports up to 31 slots per controller, hence uses separate slot
and controller structs.  pciehp has a 1:1 relationship between slot and
controller and therefore never required this separation.  Nevertheless,
because much of the code had been copy-pasted between the two drivers,
pciehp likewise uses separate structs to this very day.

The artificial separation of data structures adds unnecessary complexity
and bloat to pciehp and requires constantly chasing pointers at runtime.

Simplify the driver by merging struct slot into struct controller.
Merge the slot constructor pcie_init_slot() and the destructor
pcie_cleanup_slot() into the controller counterparts.

No functional change intended.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-09-18 17:52:15 -05:00
Lukas Wunner 80696f9914 PCI: pciehp: Tolerate Presence Detect hardwired to zero
The WiGig Bus Extension (WBE) specification allows tunneling PCIe over
IEEE 802.11.  A product implementing this spec is the wil6210 from
Wilocity (now part of Qualcomm Atheros).  It integrates a PCIe switch
with a wireless network adapter:

  00.0-+              [1ae9:0101]  Upstream Port
       +-00.0-+       [1ae9:0200]  Downstream Port
       |      +-00.0  [168c:0034]  Atheros AR9462 Wireless Network Adapter
       +-02.0         [1ae9:0201]  Downstream Port
       +-03.0         [1ae9:0201]  Downstream Port

Wirelessly attached devices presumably appear below the hotplug ports
with device ID [1ae9:0201].  Oddly, the Downstream Port [1ae9:0200]
leading to the wireless network adapter is likewise Hotplug Capable,
but has its Presence Detect State bit hardwired to zero.  Even if the
Link Active bit is set, Presence Detect is zero, so this cannot be
caused by in-band presence detection but only by broken hardware.

pciehp assumes an empty slot if Presence Detect State is zero,
regardless of Link Active being one.  Consequently, up until v4.18 it
removes the wireless network adapter in pciehp_resume().  From v4.19 it
already does so in pciehp_probe().

Be lenient towards broken hardware and assume the slot is occupied if
Link Active is set:  Introduce pciehp_card_present_or_link_active()
and use it in lieu of pciehp_get_adapter_status() everywhere, except
in pciehp_handle_presence_or_link_change() whose log messages depend
on which of Presence Detect State or Link Active is set.

Remove the Presence Detect State check from __pciehp_enable_slot()
because it is only called if either of Presence Detect State or Link
Active is set.

Caution: There is a possibility that broken hardware exists which has
working Presence Detect but hardwires Link Active to one.  On such
hardware the slot will now incorrectly be considered always occupied.
If such hardware is discovered, this commit can be rolled back and a
quirk can be added which sets is_hotplug_bridge = 0 for [1ae9:0200].

Link: https://bugzilla.kernel.org/show_bug.cgi?id=200839
Reported-and-tested-by: David Yang <mmyangfl@gmail.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Rajat Jain <rajatja@google.com>
Cc: Ashok Raj <ashok.raj@intel.com>
2018-09-18 17:52:15 -05:00
Lukas Wunner eee6e27384 PCI: pciehp: Drop hotplug_slot_ops wrappers
pciehp's ->enable_slot, ->disable_slot, ->get_attention_status and
->reset_slot callbacks are currently implemented by wrapper functions
that do nothing else but call down to a backend function.  The backends
are not called from anywhere else, so drop the wrappers and use the
backends directly as callbacks, thereby shaving off a few lines of
unnecessary code.

No functional change intended.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-09-17 16:34:36 -05:00
Lukas Wunner 7d4ba52317 PCI: pciehp: Drop unnecessary includes
Drop the following includes from pciehp source files which no longer use
any of the included symbols:

* <linux/sched/signal.h> in pciehp.h
  <linux/signal.h> in pciehp_hpc.c
  Added by commit de25968cc8 ("fix more missing includes") to
  accommodate for a call to signal_pending().
  The call was removed by commit 262303fe32 ("pciehp: fix wait command
  completion").

* <linux/interrupt.h> in pciehp_core.c
  Added by historic commit f308a2dfbe63 ("PCI: add PCI Express Port Bus
  Driver subsystem") to accommodate for a call to free_irq():
  https://git.kernel.org/tglx/history/c/f308a2dfbe63
  The call was removed by commit 407f452b05 ("pciehp: remove
  unnecessary free_irq").

* <linux/time.h> in pciehp_core.c and pciehp_hpc.c
  Added by commit 34d03419f0 ("PCIEHP: Add Electro Mechanical
  Interlock (EMI) support to the PCIE hotplug driver."),
  which was reverted by commit bd3d99c170 ("PCI: Remove untested
  Electromechanical Interlock (EMI) support in pciehp.").

* <linux/module.h> in pciehp_ctrl.c, pciehp_hpc.c and pciehp_pci.c
  Added by historic commit c16b4b14d980 ("PCI Hotplug: Add SHPC and PCI
  Express hot-plug drivers"):
  https://git.kernel.org/tglx/history/c/c16b4b14d980
  Module-related symbols were neither used back then in those files,
  nor are they used today.

* <linux/slab.h> in pciehp_ctrl.c
  Added by commit 5a0e3ad6af ("include cleanup: Update gfp.h and
  slab.h includes to prepare for breaking implicit slab.h inclusion from
  percpu.h") to accommodate for calls to kmalloc().
  The calls were removed by commit 0e94916e60 ("PCI: pciehp: Handle
  events synchronously").

* "../pci.h" in pciehp_ctrl.c
  Added by historic commit 67f4660b72f2 ("PCI: ASPM patch for") to
  accommodate for usage of the global variable pcie_mch_quirk:
  https://git.kernel.org/tglx/history/c/67f4660b72f2
  The global variable was removed by commit 0ba379ec0f ("PCI: Simplify
  hotplug mch quirk").

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-09-17 16:34:36 -05:00
Lukas Wunner 11e87702be PCI: pciehp: Differentiate between surprise and safe removal
When removing PCI devices below a hotplug bridge, pciehp marks them as
disconnected if the card is no longer present in the slot or it quiesces
them if the card is still present (by disabling INTx interrupts, bus
mastering and SERR# reporting).

To detect whether the card is still present, pciehp checks the Presence
Detect State bit in the Slot Status register.  The problem with this
approach is that even if the card is present, the link to it may be
down, and it that case it would be better to mark the devices as
disconnected instead of trying to quiesce them.  Moreover, if the card
in the slot was quickly replaced by another one, the Presence Detect
State bit would be set, yet trying to quiesce the new card's devices
would be wrong and the correct thing to do is to mark the previous
card's devices as disconnected.

Instead of looking at the Presence Detect State bit, it is better to
differentiate whether the card was surprise removed versus safely
removed (via sysfs or an Attention Button press).  On surprise removal,
the devices should be marked as disconnected, whereas on safe removal it
is correct to quiesce the devices.

The knowledge whether a surprise removal or a safe removal is at hand
does exist further up in the call stack:  A surprise removal is
initiated by pciehp_handle_presence_or_link_change(), a safe removal by
pciehp_handle_disable_request().

Pass that information down to pciehp_unconfigure_device() and use it in
lieu of the Presence Detect State bit.  While there, add kernel-doc to
pciehp_unconfigure_device() and pciehp_configure_device().

Tested-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Keith Busch <keith.busch@intel.com>
2018-09-17 16:34:35 -05:00
Lukas Wunner a50ac6bfd6 PCI: Simplify disconnected marking
Commit 89ee9f7680 ("PCI: Add device disconnected state") iterates over
the devices on a parent bus, marks each as disconnected, then marks
each device's children as disconnected using pci_walk_bus().

The same can be achieved more succinctly by calling pci_walk_bus() on
the parent bus.  Moreover, this does not need to wait until acquiring
pci_lock_rescan_remove(), so move it out of that critical section.

The critical section in err.c contains a pci_dev_get() / pci_dev_put()
pair which was apparently copy-pasted from pciehp_pci.c.  In the latter
it serves the purpose of holding the struct pci_dev in place until the
Command register is updated.  err.c doesn't do anything like that, hence
the pair is unnecessary.  Remove it.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Oza Pawandeep <poza@codeaurora.org>
Cc: Sinan Kaya <okaya@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-09-17 16:34:35 -05:00
Keith Busch 34fb6bf9b1 PCI: pciehp: Fix hot-add vs powerfault detection order
If both hot-add and power fault were observed in a single interrupt, we
handled the hot-add first, then the power fault, in this path:

  pciehp_ist
    if (events & (PDC | DLLSC))
      pciehp_handle_presence_or_link_change
        case OFF_STATE:
          pciehp_enable_slot
            __pciehp_enable_slot
              board_added
                pciehp_power_on_slot
                  ctrl->power_fault_detected = 0
                  pcie_write_cmd(ctrl, PCI_EXP_SLTCTL_PWR_ON, PCI_EXP_SLTCTL_PCC)
                pciehp_green_led_on(p_slot)             # power LED on
		pciehp_set_attention_status(p_slot, 0)  # attention LED off
    if ((events & PFD) && !ctrl->power_fault_detected)
      ctrl->power_fault_detected = 1
      pciehp_set_attention_status(1)                    # attention LED on
      pciehp_green_led_off(slot)                        # power LED off

This left the attention indicator on (even though the hot-add succeeded)
and the power indicator off (even though the slot power was on).

Fix this by checking for power faults before checking for new devices.

Prior to 0e94916e60, this was successful because everything was chained
through work queues and the order was:

  INT_PRESENCE_ON -> INT_POWER_FAULT -> ENABLE_REQ

The ENABLE_REQ cleared the power fault at the end, but now everything is
handled inline with the interrupt thread, such that the work ENABLE_REQ was
doing happens before power fault handling now.

Fixes: 0e94916e60 ("PCI: pciehp: Handle events synchronously")
Signed-off-by: Keith Busch <keith.busch@intel.com>
[bhelgaas: changelog]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
2018-09-11 08:47:42 -05:00
Bjorn Helgaas 3a48dc6fc2 Merge branch 'pci/virtualization'
- To avoid bus errors, enable PASID only if entire path supports End-End
    TLP prefixes (Sinan Kaya)

  - Unify slot and bus reset functions and remove hotplug knowledge from
    callers (Sinan Kaya)

  - Add Function-Level Reset quirks for Intel and Samsung NVMe devices to
    fix guest reboot issues (Alex Williamson)

  - Add function 1 DMA alias quirk for Marvell 88SS9183 PCIe SSD Controller
    (Bjorn Helgaas)

* pci/virtualization:
  PCI: Add function 1 DMA alias quirk for Marvell 88SS9183
  PCI: Delay after FLR of Intel DC P3700 NVMe
  PCI: Disable Samsung SM961/PM961 NVMe before FLR
  PCI: Export pcie_has_flr()
  PCI: Rename pci_try_reset_bus() to pci_reset_bus()
  PCI: Deprecate pci_reset_bus() and pci_reset_slot() functions
  PCI: Unify try slot and bus reset API
  PCI: Hide pci_reset_bridge_secondary_bus() from drivers
  IB/hfi1: Use pci_try_reset_bus() for initiating PCI Secondary Bus Reset
  PCI: Handle error return from pci_reset_bridge_secondary_bus()
  PCI/IOV: Tidy pci_sriov_set_totalvfs()
  PCI: Enable PASID only if entire path supports End-End TLP prefixes

# Conflicts:
#	drivers/pci/hotplug/pciehp_hpc.c
2018-08-15 14:59:06 -05:00
Bjorn Helgaas a40f72db8a Merge branch 'pci/misc'
- Mark fall-through switch cases before enabling -Wimplicit-fallthrough
    (Gustavo A. R. Silva)

  - Move DMA-debug PCI init from arch code to PCI core (Christoph Hellwig)

  - Fix pci_request_irq() usage of IRQF_ONESHOT when no handler is supplied
    (Heiner Kallweit)

  - Unify PCI and DMA direction #defines (Shunyong Yang)

  - Add PCI_DEVICE_DATA() macro (Andy Shevchenko)

  - Check for VPD completion before checking for timeout (Bert Kenward)

  - Limit Netronome NFP5000 config space size to work around erratum (Jakub
    Kicinski)

* pci/misc:
  PCI: Limit config space size for Netronome NFP5000
  PCI/VPD: Check for VPD access completion before checking for timeout
  PCI: Add PCI_DEVICE_DATA() macro to fully describe device ID entry
  PCI: Unify PCI and normal DMA direction definitions
  PCI: Use IRQF_ONESHOT if pci_request_irq() called with no handler
  PCI: Call dma_debug_add_bus() for pci_bus_type from PCI core
  PCI: Mark fall-through switch cases before enabling -Wimplicit-fallthrough

# Conflicts:
#	drivers/pci/hotplug/pciehp_ctrl.c
2018-08-15 14:58:54 -05:00
Bjorn Helgaas c0638a4553 Merge branch 'pci/hotplug'
- Simplify SHPC existence/permission checks (Bjorn Helgaas)

  - Remove hotplug sample skeleton driver (Lukas Wunner)

  - Convert pciehp to threaded IRQ handling (Lukas Wunner)

  - Improve pciehp tolerance of missed events and initially unstable links
    (Lukas Wunner)

  - Clear spurious pciehp events on resume (Lukas Wunner)

  - Add pciehp runtime PM support, including for Thunderbolt controllers
    (Lukas Wunner)

  - Support interrupts from pciehp bridges in D3hot (Lukas Wunner)

* pci/hotplug:
  PCI: pciehp: Deduplicate presence check on probe & resume
  PCI: pciehp: Avoid implicit fallthroughs in switch statements
  PCI: Whitelist Thunderbolt ports for runtime D3
  PCI: Whitelist native hotplug ports for runtime D3
  PCI: sysfs: Resume to D0 on function reset
  PCI: pciehp: Resume parent to D0 on config space access
  PCI: pciehp: Resume to D0 on enable/disable
  PCI: pciehp: Support interrupts sent from D3hot
  PCI: pciehp: Obey compulsory command delay after resume
  PCI: pciehp: Clear spurious events earlier on resume
  PCI: portdrv: Deduplicate PM callback iterator
  PCI: pciehp: Avoid slot access during reset
  PCI: pciehp: Always enable occupied slot on probe
  PCI: pciehp: Become resilient to missed events
  PCI: pciehp: Tolerate initially unstable link
  PCI: pciehp: Declare pciehp_enable/disable_slot() static
  PCI: pciehp: Drop enable/disable lock
  PCI: pciehp: Enable/disable exclusively from IRQ thread
  PCI: pciehp: Track enable/disable status
  PCI: pciehp: Publish to user space last on probe
  PCI: hotplug: Demidlayer registration with the core
  PCI: pciehp: Drop slot workqueue
  PCI: pciehp: Handle events synchronously
  PCI: pciehp: Stop blinking on slot enable failure
  PCI: pciehp: Convert to threaded polling
  PCI: pciehp: Convert to threaded IRQ
  PCI: pciehp: Document struct slot and struct controller
  PCI: pciehp: Declare pciehp_unconfigure_device() void
  PCI: pciehp: Drop unnecessary NULL pointer check
  PCI: pciehp: Fix unprotected list iteration in IRQ handler
  PCI: pciehp: Fix use-after-free on unplug
  PCI: hotplug: Don't leak pci_slot on registration failure
  PCI: hotplug: Delete skeleton driver
  PCI: shpchp: Separate existence of SHPC and permission to use it
2018-08-15 14:58:52 -05:00
Lukas Wunner 4e6a13356f PCI: pciehp: Deduplicate presence check on probe & resume
On driver probe and on resume from system sleep, pciehp checks the
Presence Detect State bit in the Slot Status register to bring up an
occupied slot or bring down an unoccupied slot.  Both code paths are
identical, so deduplicate them per Mika's request.

On probe, an additional check is performed to disable power of an
unoccupied slot.  This can e.g. happen if power was enabled by BIOS.
It cannot happen once pciehp has taken control, hence is not necessary
on resume:  The Slot Control register is set to the same value that it
had on suspend by pci_restore_state(), so if the slot was occupied,
power is enabled and if it wasn't, power is disabled.  Should occupancy
have changed during the system sleep transition, power is adjusted by
bringing up or down the slot per the paragraph above.

To allow for deduplication of the presence check, move the power check
to pcie_init().  This seems safer anyway, because right now it is
performed while interrupts are already enabled, and although I can't
think of a scenario where pciehp_power_off_slot() and the IRQ thread
collide, it does feel brittle.

However this means that pcie_init() may now write to the Slot Control
register before the IRQ is requested.  If both the CCIE and HPIE bits
happen to be set, pcie_wait_cmd() will wait for an interrupt (instead
of polling the Command Completed bit) and eventually emit a timeout
message.  Additionally, if a level-triggered INTx interrupt is used,
the user may see a spurious interrupt splat.  Avoid by disabling
interrupts before disabling power.  (Normally the HPIE and CCIE bits
should be clear on probe, but conceivably they may already have been
set e.g. by BIOS.)

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2018-07-31 13:27:24 -05:00
Lukas Wunner 8bb46b079d PCI: pciehp: Avoid implicit fallthroughs in switch statements
Per Mika's request, add an explicit break to the last case of switch
statements everywhere in pciehp to be more defensive towards future
amendments.

Per Gustavo's request, mark all non-empty implicit fallthroughs with a
comment to silence warnings triggered by -Wimplicit-fallthrough=2.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
2018-07-31 13:26:33 -05:00
Hari Vyas 44bda4b7d2 PCI: Fix is_added/is_busmaster race condition
When a PCI device is detected, pdev->is_added is set to 1 and proc and
sysfs entries are created.

When the device is removed, pdev->is_added is checked for one and then
device is detached with clearing of proc and sys entries and at end,
pdev->is_added is set to 0.

is_added and is_busmaster are bit fields in pci_dev structure sharing same
memory location.

A strange issue was observed with multiple removal and rescan of a PCIe
NVMe device using sysfs commands where is_added flag was observed as zero
instead of one while removing device and proc,sys entries are not cleared.
This causes issue in later device addition with warning message
"proc_dir_entry" already registered.

Debugging revealed a race condition between the PCI core setting the
is_added bit in pci_bus_add_device() and the NVMe driver reset work-queue
setting the is_busmaster bit in pci_set_master().  As these fields are not
handled atomically, that clears the is_added bit.

Move the is_added bit to a separate private flag variable and use atomic
functions to set and retrieve the device addition state.  This avoids the
race because is_added no longer shares a memory location with is_busmaster.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=200283
Signed-off-by: Hari Vyas <hari.vyas@broadcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
2018-07-31 11:27:54 -05:00
Lukas Wunner 4417aa45c1 PCI: pciehp: Resume parent to D0 on config space access
Ensure accessibility of a hotplug port's config space when accessed via
sysfs by resuming its parent to D0.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
2018-07-31 11:09:36 -05:00
Lukas Wunner 8350307454 PCI: pciehp: Resume to D0 on enable/disable
pciehp's IRQ thread ensures accessibility of the port by runtime resuming
its parent to D0.  However when the slot is enabled/disabled, the port
itself needs to be in D0 because its secondary bus is accessed in:

    pciehp_check_link_status(),
    pciehp_configure_device() (both called from board_added())
and
    pciehp_unconfigure_device() (called from remove_board()).

Thus, acquire a runtime PM ref on enable/disablement of the slot.

Yinghai Lu additionally discovered that some SkyLake servers feature a
Power Controller for their PCIe hotplug ports (PCIe r3.1, sec 6.7.1.8)
which requires the port to be in D0 when invoking

    pciehp_power_on_slot() (likewise called from board_added()).

If slot power is turned on while in D3hot, link training later fails:
https://lkml.kernel.org/r/20170205073454.GA253@wunner.de

The spec is silent about such a requirement, but it seems prudent to
assume that any hotplug port with a Power Controller may need this.

The present commit holds a runtime PM ref whenever slot power is turned
on and off, but it doesn't keep the port in D0 as long as slot power is
on.  If vendors determine that's necessary, they need to amend pciehp to
acquire a runtime PM ref in pciehp_power_on_slot() and release one in
pciehp_power_off_slot().

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
2018-07-31 11:09:36 -05:00
Lukas Wunner 6b08c3854c PCI: pciehp: Support interrupts sent from D3hot
If a hotplug port is able to send an interrupt, one would naively assume
that it is accessible at that moment.  After all, if it wouldn't be
accessible, i.e. if its parent is in D3hot and the link to the hotplug
port is thus down, how should an interrupt come through?

It turns out that assumption is wrong at least for Thunderbolt:  Even
though its parents are in D3hot, a Thunderbolt hotplug port is able to
signal interrupts.  Because the port's config space is inaccessible and
resuming the parents may sleep, the hard IRQ handler has to defer
runtime resuming the parents and reading the Slot Status register to the
IRQ thread.

If the hotplug port uses a level-triggered INTx interrupt, it needs to
be masked until the IRQ thread has cleared the signaled events.  For
simplicity, this commit also masks edge-triggered MSI/MSI-X interrupts.
Note that if the interrupt is shared (which can only happen for INTx),
other devices are starved from receiving interrupts until the IRQ thread
is scheduled, has runtime resumed the hotplug port's parents and has
read and cleared the Slot Status register.

That delay is dominated by the 10 ms D3hot->D0 transition time of each
parent port.  The worst case is a Thunderbolt downstream port at the
end of a daisy chain:  There may be up to six Thunderbolt controllers
in-between it and the root port, each comprising an upstream and
downstream port, plus its own upstream port.  That's 13 x 10 = 130 ms.
Possible mitigations are polling the interrupt while it's disabled or
reducing the d3_delay of Thunderbolt ports if possible.

Open code masking of the interrupt instead of requesting it with the
IRQF_ONESHOT flag to minimize the period during which it is masked.
(IRQF_ONESHOT unmasks the IRQ only after the IRQ thread has finished.)

PCIe r4.0 sec 6.7.3.4 states that "If wake generation is required by the
associated form factor specification, a hotplug capable Downstream Port
must support generation of a wakeup event (using the PME mechanism) on
hotplug events that occur when the system is in a sleep state or the
Port is in device state D1, D2, or D3Hot."

This would seem to imply that PME needs to be enabled on the hotplug
port when it is runtime suspended.  pci_enable_wake() currently doesn't
enable PME on bridges, it may be necessary to add an exemption for
hotplug bridges there.  On "Light Ridge" Thunderbolt controllers, the
PME_Status bit is not set when an interrupt occurs while the hotplug
port is in D3hot, even if PME is enabled.  (I've tested this on a Mac
and we hardcode the OSC_PCI_EXPRESS_PME_CONTROL bit to 0 on Macs in
negotiate_os_control(), modifying it to 1 didn't change the behavior.)

(Side note:  Section 6.7.3.4 also states that "PME and Hot-Plug Event
interrupts (when both are implemented) always share the same MSI or
MSI-X vector".  That would only seem to apply to Root Ports, however
the section never mentions Root Ports, only Downstream Ports.  This is
explained in the definition of "Downstream Port" in the "Terms and
Acronyms" section of the PCIe Base Spec:  "The Ports on a Switch that
are not the Upstream Port are Downstream Ports.  All Ports on a Root
Complex are Downstream Ports.")

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
2018-07-31 11:08:56 -05:00
Lukas Wunner 469e764c4a PCI: pciehp: Obey compulsory command delay after resume
Upon resume from system sleep, the Slot Control register is written via:

  pci_pm_resume_noirq()
    pci_pm_default_resume_early()
      pci_restore_state()
        pci_restore_pcie_state()

PCIe r4.0, sec 6.7.3.2 says that after "issuing a write transaction that
targets any portion of the Port's Slot Control register, [...] software
must wait for [the] command to complete before issuing the next command".

pciehp currently fails to enforce that rule after the above-mentioned
write.  Fix it.

(Moving restoration of the Slot Control register to pciehp doesn't seem
to make sense because the other PCIe hotplug drivers may need it as
well.)

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-07-31 11:07:59 -05:00
Lukas Wunner 7903782460 PCI: pciehp: Clear spurious events earlier on resume
Thunderbolt hotplug ports that were occupied before system sleep resume
with their downstream link in "off" state.  Only after the Thunderbolt
controller has reestablished the PCIe tunnels does the link go up.
As a result, a spurious Presence Detect Changed and/or Data Link Layer
State Changed event occurs.

The events are not immediately acted upon because tunnel reestablishment
happens in the ->resume_noirq phase, when interrupts are still disabled.
Also, notification of events may initially be disabled in the Slot
Control register when coming out of system sleep and is reenabled in the
->resume_noirq phase through:

  pci_pm_resume_noirq()
    pci_pm_default_resume_early()
      pci_restore_state()
        pci_restore_pcie_state()

It is not guaranteed that the events are acted upon at all:  PCIe r4.0,
sec 6.7.3.4 says that "a port may optionally send an MSI when there are
hot-plug events that occur while interrupt generation is disabled, and
interrupt generation is subsequently enabled."  Note the "optionally".

If an MSI is sent, pciehp will gratuitously turn the slot off and back
on once the ->resume_early phase has commenced.

If an MSI is not sent, the extant, unacknowledged events in the Slot
Status register will prevent future notification of presence or link
changes.

Commit 13c65840fe ("PCI: pciehp: Clear Presence Detect and Data Link
Layer Status Changed on resume") fixed the latter by clearing the events
in the ->resume phase.  Move this to the ->resume_noirq phase to also
fix the gratuitous disable/enablement of the slot.

The commit further restored the Slot Control register in the ->resume
phase, but that's dispensable because as shown above it's already been
done in the ->resume_noirq phase.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
2018-07-31 11:07:59 -05:00
Lukas Wunner 5b3f7b7d06 PCI: pciehp: Avoid slot access during reset
The ->reset_slot callback introduced by commits:

  2e35afaefe ("PCI: pciehp: Add reset_slot() method") and
  06a8d89af5 ("PCI: pciehp: Disable link notification across slot reset")

disables notification of Presence Detect Changed and Data Link Layer
State Changed events for the duration of a secondary bus reset.

However a bus reset not only triggers these events, but may also clear
the Presence Detect State bit in the Slot Status register and the Data
Link Layer Link Active bit in the Link Status register momentarily.
According to Sinan Kaya:

 "I know for a fact that bus reset clears the Data Link Layer Active bit
  as soon as link goes down.  It gets set again following link up.
  Presence detect depends on the HW implementation.  QDT root ports
  don't change presence detect for instance since nobody actually
  removed the card.  If an implementation supports in-band presence
  detect, the answer is yes.  As soon as the link goes down, presence
  detect bit will get cleared until recovery."
  https://lkml.kernel.org/r/42e72f83-3b24-f7ef-e5bc-290fae99259a@codeaurora.org

  In-band presence detect is also covered in Table 4-15 in PCIe r4.0,
  sec 4.2.6.

pciehp should therefore ensure that any parts of the driver that access
those bits do not run concurrently to a bus reset.  The only precaution
the commits took to that effect was to halt interrupt polling.  They
made no effort to drain the slot workqueue, cancel an outstanding
Attention Button work, or block slot enable/disable requests via sysfs
and in the ->probe hook.

Now that pciehp is converted to enable/disable the slot exclusively from
the IRQ thread, the only places accessing the two above-mentioned bits
are the IRQ thread and the ->probe hook.  Add locking to serialize them
with a bus reset.  This obviates the need to halt interrupt polling.
Do not add locking to the ->get_adapter_status sysfs callback to afford
users unfettered access to that bit.  Use an rw_semaphore in lieu of a
regular mutex to allow parallel execution of the non-reset code paths
accessing the critical bits, i.e. the IRQ thread and the ->probe hook.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Rajat Jain <rajatja@google.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Sinan Kaya <okaya@kernel.org>
2018-07-31 10:50:31 -05:00
Lukas Wunner cdf6b73621 PCI: pciehp: Always enable occupied slot on probe
Per PCIe r4.0, sec 6.7.3.4, a "port may optionally send an MSI when
there are hot-plug events that occur while interrupt generation is
disabled, and interrupt generation is subsequently enabled."

On probe, we currently clear all event bits in the Slot Status register
with the notable exception of the Presence Detect Changed bit.  Thereby
we seek to receive an interrupt for an already occupied slot once event
notification is enabled.

But because the interrupt is optional, users may have to specify the
pciehp_force parameter on the command line, which is inconvenient.

Moreover, now that pciehp's event handling has become resilient to
missed events, a Presence Detect Changed interrupt for a slot which is
powered on is interpreted as removal of the card.  If the slot has
already been brought up by the BIOS, receiving such an interrupt on
probe causes the slot to be powered off and immediately back on, which
is likewise undesirable.

Avoid both issues by making the behavior of pciehp_force the default and
clearing the Presence Detect Changed bit on probe.

Note that the stated purpose of pciehp_force per the MODULE_PARM_DESC
("Force pciehp, even if OSHP is missing") seems nonsensical because the
OSHP control method is only relevant for SHCP slots according to the
PCI Firmware specification r3.0, sec 4.8.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
2018-07-23 17:04:16 -05:00
Lukas Wunner d331710ea7 PCI: pciehp: Become resilient to missed events
A hotplug port's Slot Status register does not count how often each type
of event occurred, it only records the fact *that* an event has occurred.

Previously pciehp queued a work item for each event.  But if it missed
an event, e.g. removal of a card in-between two back-to-back insertions,
it queued up the wrong work item or no work item at all.  Commit
fad214b0aa ("PCI: pciehp: Process all hotplug events before looking
for new ones") sought to improve the situation by shrinking the window
during which events may be missed.

But Stefan Roese reports unbalanced Card present and Link Up events,
suggesting that we're still missing events if they occur very rapidly.
Bjorn Helgaas responds that he considers pciehp's event handling
"baroque" and calls for its simplification and rationalization:
https://lkml.kernel.org/r/20180202192045.GA53759@bhelgaas-glaptop.roam.corp.google.com

It gets worse once a hotplug port is runtime suspended:  The port can
signal an interrupt while it and its parents are in D3hot, i.e. while
it is inaccessible.  By the time we've runtime resumed all parents to D0
and read the port's Slot Status register, we may have missed an arbitrary
number of events.  Event handling therefore needs to be reworked to
become resilient to missed events.

Assume that a Presence Detect Changed event has occurred.
Consider the following truth table:
- Slot is in OFF_STATE and is currently empty.    => Do nothing.
  (The event is trailing a Link Down or we've
  missed an insertion and subsequent removal.)
- Slot is in OFF_STATE and is currently occupied. => Turn the slot on.
- Slot is in ON_STATE  and is currently empty.    => Turn the slot off.
- Slot is in ON_STATE  and is currently occupied. => Turn the slot off,
  (Be cautious and assume the card in                then back on.
  the slot isn't the same as before.)

This leads to the following simple algorithm:
1 If the slot is in ON_STATE, turn it off unconditionally.
2 If the slot is currently occupied, turn it on.

Because those actions are now carried out synchronously, rather than by
scheduled work items, pciehp reacts to the *current* situation and
missed events no longer matter.

Data Link Layer State Changed events can be handled identically to
Presence Detect Changed events.  Note that in the above truth table,
a Link Up trailing a Card present event didn't have to be accounted for:
It is filtered out by pciehp_check_link_status().

As for Attention Button Pressed events, PCIe r4.0, sec 6.7.1.5 says:
"Once the Power Indicator begins blinking, a 5-second abort interval
exists during which a second depression of the Attention Button cancels
the operation."  In other words, the user can only expect the system to
react to a button press after it starts blinking.  Missed button presses
that occur in-between are irrelevant.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Stefan Roese <sr@denx.de>
Cc: Mayurkumar Patel <mayurkumar.patel@intel.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
2018-07-23 17:04:16 -05:00
Lukas Wunner 6c35a1ac3d PCI: pciehp: Tolerate initially unstable link
When a device is hotplugged, Presence Detect and Link Up events often do
not occur simultaneously, but with a lag of a few milliseconds.  Only
the first event received is relevant, the other one can be disregarded.

Moreover, Stefan Roese reports that on certain platforms, Link State and
Presence Detect may flap for up to 100 ms before stabilizing, suggesting
that such events should be disregarded for at least this long:
https://lkml.kernel.org/r/20180130084121.18653-1-sr@denx.de

On slot enablement, pciehp_check_link_status() waits for 100 ms per
PCIe r4.0, sec 6.7.3.3, then probes the hotplugged device's vendor
register for up to 1 second.

If this succeeds, the link is definitely up, so ignore any Presence
Detect or Link State events that occurred up to this point.

pciehp_check_link_status() then checks the Link Training bit in the
Link Status register.  This is the final opportunity to detect
inaccessibility of the device and abort slot enablement.  Any link
or presence change that occurs afterwards will cause the slot to be
disabled again immediately after attempting to enable it.

The astute reviewer may appreciate that achieving this behavior would be
more complicated had pciehp not just been converted to enable/disable
the slot exclusively from the IRQ thread:  When the slot is enabled via
sysfs, each link or presence flap would otherwise cause the IRQ thread
to run and it would have to sense that those events are belonging to a
concurrent slot enablement operation and disregard them.  It would be
much more difficult than this mere 3 line change.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Stefan Roese <sr@denx.de>
2018-07-23 17:04:16 -05:00
Lukas Wunner 25c83b84b1 PCI: pciehp: Declare pciehp_enable/disable_slot() static
No callers of pciehp_enable/disable_slot() outside of pciehp_ctrl.c
remain, so declare the functions static.  For now this requires forward
declarations.  Those can be eliminated by reshuffling functions once the
ongoing effort to refactor the driver has settled.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-07-23 17:04:15 -05:00
Lukas Wunner 1656716d45 PCI: pciehp: Drop enable/disable lock
Previously slot enablement and disablement could happen concurrently.
But now it's under the exclusive control of the IRQ thread, rendering
the locking obsolete.  Drop it.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-07-23 17:04:15 -05:00
Lukas Wunner 32a8cef274 PCI: pciehp: Enable/disable exclusively from IRQ thread
Besides the IRQ thread, there are several other places in the driver
which enable or disable the slot:

- pciehp_probe() enables the slot if it's occupied and the pciehp_force
  module parameter is used.

- pciehp_resume() enables or disables the slot after system sleep.

- pciehp_queue_pushbutton_work() enables or disables the slot after the
  5 second delay following an Attention Button press.

- pciehp_sysfs_enable_slot() and pciehp_sysfs_disable_slot() enable or
  disable the slot on sysfs write.

This requires locking and complicates pciehp's state machine.

A simplification can be achieved by enabling and disabling the slot
exclusively from the IRQ thread.

Amend the functions listed above to request slot enable/disablement from
the IRQ thread by either synthesizing a Presence Detect Changed event or,
in the case of a disable user request (via sysfs or an Attention Button
press), submitting a newly introduced force disable request.  The latter
is needed because the slot shall be forced off despite being occupied.
For this force disable request, avoid colliding with Slot Status register
bits by using a bit number greater than 16.

For synchronous execution of requests (on sysfs write), wait for the
request to finish and retrieve the result.  There can only ever be one
sysfs write in flight due to the locking in kernfs_fop_write(), hence
there is no risk of returning the result of a different sysfs request to
user space.

The POWERON_STATE and POWEROFF_STATE is now no longer entered by the
above-listed functions, but solely by the IRQ thread when it begins a
power transition.  Afterwards, it moves to STATIC_STATE.  The same
applies to canceling the Attention Button work, it likewise becomes an
IRQ thread only operation.

An immediate consequence is that the POWERON_STATE and POWEROFF_STATE is
never observed by the IRQ thread itself, only by functions called in a
different context, such as pciehp_sysfs_enable_slot().  So remove
handling of these states from pciehp_handle_button_press() and
pciehp_handle_link_change() which are exclusively called from the IRQ
thread.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-07-23 17:04:15 -05:00
Lukas Wunner 9590192f25 PCI: pciehp: Track enable/disable status
handle_button_press_event() currently determines whether the slot has
been turned on or off by looking at the Power Controller Control bit in
the Slot Control register.  This assumes that an attention button
implies presence of a power controller even though that's not mandated
by the spec.  Moreover the Power Controller Control bit is unreliable
when a power fault occurs (PCIe r4.0, sec 6.7.1.8).  This issue has
existed since the driver was introduced in 2004.

Fix by replacing STATIC_STATE with ON_STATE and OFF_STATE and tracking
whether the slot has been turned on or off.  This is also a required
ingredient to make pciehp resilient to missed events, which is the
object of an upcoming commit.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-07-23 17:04:14 -05:00
Lukas Wunner 774d446b0f PCI: pciehp: Publish to user space last on probe
The PCI hotplug core has just been refactored to separate slot
initialization for in-kernel use from publication to user space.

Take advantage of it in pciehp by publishing to user space last on
probe.  This will allow enable/disablement of the slot exclusively from
the IRQ thread because the IRQ is requested after initialization for
in-kernel use (thereby getting its unique name needed by the IRQ thread)
but before user space is able to submit enable/disable requests.

On teardown, the order is the same in reverse:  The user space interface
is removed prior to freeing the IRQ and destroying the slot.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-07-23 17:04:14 -05:00
Lukas Wunner 51bbf9bee3 PCI: hotplug: Demidlayer registration with the core
When a hotplug driver calls pci_hp_register(), all steps necessary for
registration are carried out in one go, including creation of a kobject
and addition to sysfs.  That's a problem for pciehp once it's converted
to enable/disable the slot exclusively from the IRQ thread:  The thread
needs to be spawned after creation of the kobject (because it uses the
kobject's name), but before addition to sysfs (because it will handle
enable/disable requests submitted via sysfs).

pci_hp_deregister() does offer a ->release callback that's invoked
after deletion from sysfs and before destruction of the kobject.  But
because pci_hp_register() doesn't offer a counterpart, hotplug drivers'
->probe and ->remove code becomes asymmetric, which is error prone
as recently discovered use-after-free bugs in pciehp's ->remove hook
have shown.

In a sense, this appears to be a case of the midlayer antipattern:

   "The core thesis of the "midlayer mistake" is that midlayers are
    bad and should not exist.  That common functionality which it is
    so tempting to put in a midlayer should instead be provided as
    library routines which can [be] used, augmented, or ignored by
    each bottom level driver independently.  Thus every subsystem
    that supports multiple implementations (or drivers) should
    provide a very thin top layer which calls directly into the
    bottom layer drivers, and a rich library of support code that
    eases the implementation of those drivers.  This library is
    available to, but not forced upon, those drivers."
        --  Neil Brown (2009), https://lwn.net/Articles/336262/

The presence of midlayer traits in the PCI hotplug core might be ascribed
to its age:  When it was introduced in February 2002, the blessings of a
library approach might not have been well known:
https://git.kernel.org/tglx/history/c/a8a2069f432c

For comparison, the driver core does offer split functions for creating
a kobject (device_initialize()) and addition to sysfs (device_add()) as
an alternative to carrying out everything at once (device_register()).
This was introduced in October 2002:
https://git.kernel.org/tglx/history/c/8b290eb19962

The odd ->release callback in the PCI hotplug core was added in 2003:
https://git.kernel.org/tglx/history/c/69f8d663b595

Clearly, a library approach would not force every hotplug driver to
implement a ->release callback, but rather allow the driver to remove
the sysfs files, release its data structures and finally destroy the
kobject.  Alternatively, a driver may choose to remove everything with
pci_hp_deregister(), then release its data structures.

To this end, offer drivers pci_hp_initialize() and pci_hp_add() as a
split-up version of pci_hp_register().  Likewise, offer pci_hp_del()
and pci_hp_destroy() as a split-up version of pci_hp_deregister().

Eliminate the ->release callback and move its code into each driver's
teardown routine.

Declare pci_hp_deregister() void, in keeping with the usual kernel
pattern that enablement can fail, but disablement cannot.  It only
returned an error if the caller passed in a NULL pointer or a slot which
has never or is no longer registered or is sharing its name with another
slot.  Those would be bugs, so WARN about them.  Few hotplug drivers
actually checked the return value and those that did only printed a
useless error message to dmesg.  Remove that.

For most drivers the conversion was straightforward since it doesn't
matter whether the code in the ->release callback is executed before or
after destruction of the kobject.  But in the case of ibmphp, it was
unclear to me whether setting slot_cur->ctrl and slot_cur->bus_on to
NULL needs to happen before the kobject is destroyed, so I erred on
the side of caution and ensured that the order stays the same.  Another
nontrivial case is pnv_php, I've found the list and kref logic difficult
to understand, however my impression was that it is safe to delete the
list element and drop the references until after the kobject is
destroyed.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>  # drivers/platform/x86
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Scott Murray <scott@spiteful.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Corentin Chary <corentin.chary@gmail.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Andy Shevchenko <andy@infradead.org>
2018-07-23 17:04:13 -05:00
Lukas Wunner 55a6b7a657 PCI: pciehp: Drop slot workqueue
Previously the slot workqueue was used to handle events and enable or
disable the slot.  That's no longer the case as those tasks are done
synchronously in the IRQ thread.  The slot workqueue is thus merely used
to handle a button press after the 5 second delay and only one such work
item may be in flight at any given time.  A separate workqueue isn't
necessary for this simple task, so use the system workqueue instead.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-07-23 17:04:13 -05:00
Lukas Wunner 0e94916e60 PCI: pciehp: Handle events synchronously
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: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-07-23 17:04:12 -05:00
Lukas Wunner b0ccd9dd5d PCI: pciehp: Stop blinking on slot enable failure
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: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-07-23 17:04:12 -05:00
Lukas Wunner ec07a44730 PCI: pciehp: Convert to threaded polling
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: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
2018-07-23 17:04:12 -05:00
Lukas Wunner 7b4ce26bcf PCI: pciehp: Convert to threaded IRQ
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 5d386e1ac4 ("pciehp: Event handling rework"), the
latter in 2009 with commit 3aa551c9b4 ("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 fad214b0aa ("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: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn 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>
2018-07-23 17:04:12 -05:00
Lukas Wunner 4aed1cd6fb PCI: pciehp: Document struct slot and struct controller
Document the driver's data structures to lower the barrier to entry for
contributors.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-07-23 17:04:12 -05:00
Lukas Wunner 1d2e2673dc PCI: pciehp: Declare pciehp_unconfigure_device() void
Since commit 0f4bd8014d ("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: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
2018-07-23 17:04:11 -05:00
Lukas Wunner 6641311df9 PCI: pciehp: Drop unnecessary NULL pointer check
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/c16b4b14d980

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-07-23 17:04:11 -05:00
Lukas Wunner 1204e35bed PCI: pciehp: Fix unprotected list iteration in IRQ handler
Commit b440bde74f ("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: b440bde74f ("PCI: Add pci_ignore_hotplug() to ignore hotplug events for a device")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org
2018-07-23 17:04:10 -05:00
Lukas Wunner 281e878eab PCI: pciehp: Fix use-after-free on unplug
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: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org # v2.6.4
2018-07-23 17:04:10 -05:00
Lukas Wunner 4ce6435820 PCI: hotplug: Don't leak pci_slot on registration failure
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: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org # v2.4.15+
Cc: Greg Kroah-Hartman <greg@kroah.com>
2018-07-23 17:04:10 -05:00
Lukas Wunner b4efce5c47 PCI: hotplug: Delete skeleton driver
Ten years ago, commit 58319b802a ("PCI: Hotplug core: remove 'name'")
dropped the name element from struct hotplug_slot but neglected to update
the skeleton driver.

That same year, commit f46753c5e3 ("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: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Christoph Hellwig <hch@lst.de>
2018-07-23 17:04:10 -05:00
Sinan Kaya 381634cad1 PCI: Hide pci_reset_bridge_secondary_bus() from drivers
Rename pci_reset_bridge_secondary_bus() to pci_bridge_secondary_bus_reset()
and move the declaration from linux/pci.h to drivers/pci.h to be used
internally in PCI directory only.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-07-19 18:04:23 -05:00
Sinan Kaya 1842623850 PCI: Handle error return from pci_reset_bridge_secondary_bus()
Commit 01fd61c0b9 ("PCI: Add a return type for
pci_reset_bridge_secondary_bus()") added a return value to the function to
return if a device is accessible following a reset.  Callers are not
checking the value.

Pass error code up high in the stack if device is not accessible.

Fixes: 01fd61c0b9 ("PCI: Add a return type for pci_reset_bridge_secondary_bus()")
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-07-19 18:04:23 -05:00
Gustavo A. R. Silva d6488ac19a PCI: Mark fall-through switch cases before enabling -Wimplicit-fallthrough
In preparation to enabling -Wimplicit-fallthrough, mark switch cases where
we are expecting to fall through.

Warning level 2 was used: -Wimplicit-fallthrough=2

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-07-12 16:55:57 -05:00
Bjorn Helgaas b03799b0cb PCI: shpchp: Separate existence of SHPC and permission to use it
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: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2018-06-26 15:38:28 -05:00
Bjorn Helgaas 6f6f42466d PCI: shpchp: Manage SHPC unconditionally on non-ACPI systems
An SHPC can be operated either by platform firmware or by the OS.  The OS
uses a host bridge ACPI _OSC method to negotiate for control of SHPC.  If
firmware wants to prevent an OS from operating an SHPC, it must supply an
_OSC method that declines to grant SHPC ownership to the OS.

If acpi_pci_find_root() returns NULL, it means there's no ACPI host bridge
device (PNP0A03 or PNP0A08) and hence no _OSC method, so the OS is always
allowed to manage the SHPC.

Fix a NULL pointer dereference when CONFIG_ACPI=y but the current
hardware/firmware platform doesn't support ACPI.  In that case,
acpi_get_hp_hw_control_from_firmware() is implemented but
acpi_pci_find_root() returns NULL.

Fixes: 90cc0c3cc7 ("PCI: shpchp: Add shpchp_is_native()")
Link: https://lkml.kernel.org/r/20180621164715.28160-1-marc.zyngier@arm.com
Reported-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2018-06-26 08:22:45 -05:00
Bjorn Helgaas f64c146410 Merge branch 'pci/hotplug'
- fix use-before-set error in ibmphp (Dan Carpenter)

  - fix pciehp timeouts caused by Command Completed errata (Bjorn Helgaas)

  - fix refcounting in pnv_php hotplug (Julia Lawall)

  - clear pciehp Presence Detect and Data Link Layer Status Changed on
    resume so we don't miss hotplug events (Mika Westerberg)

  - only request pciehp control if we support it, so platform can use ACPI
    hotplug otherwise (Mika Westerberg)

  - convert SHPC to be builtin only (Mika Westerberg)

  - request SHPC control via _OSC if we support it (Mika Westerberg)

  - simplify SHPC handoff from firmware (Mika Westerberg)

* pci/hotplug:
  PCI: Improve "partially hidden behind bridge" log message
  PCI: Improve pci_scan_bridge() and pci_scan_bridge_extend() doc
  PCI: Move resource distribution for single bridge outside loop
  PCI: Account for all bridges on bus when distributing bus numbers
  ACPI / hotplug / PCI: Drop unnecessary parentheses
  ACPI / hotplug / PCI: Mark stale PCI devices disconnected
  ACPI / hotplug / PCI: Don't scan bridges managed by native hotplug
  PCI: hotplug: Add hotplug_is_native()
  PCI: shpchp: Add shpchp_is_native()
  PCI: shpchp: Fix AMD POGO identification
  PCI: shpchp: Use dev_printk() for OSHP-related messages
  PCI: shpchp: Remove get_hp_hw_control_from_firmware() wrapper
  PCI: shpchp: Remove acpi_get_hp_hw_control_from_firmware() flags
  PCI: shpchp: Rely on previous _OSC results
  PCI: shpchp: Request SHPC control via _OSC when adding host bridge
  PCI: shpchp: Convert SHPC to be builtin only
  PCI: pciehp: Make pciehp_is_native() stricter
  PCI: pciehp: Rename host->native_hotplug to host->native_pcie_hotplug
  PCI: pciehp: Request control of native hotplug only if supported
  PCI: pciehp: Clear Presence Detect and Data Link Layer Status Changed on resume
  PCI: pnv_php: Add missing of_node_put()
  PCI: pciehp: Add quirk for Command Completed errata
  PCI: Add Qualcomm vendor ID
  PCI: ibmphp: Fix use-before-set in get_max_bus_speed()

# Conflicts:
#	drivers/acpi/pci_root.c
2018-06-06 16:10:10 -05:00
Mika Westerberg 9337a49362 ACPI / hotplug / PCI: Drop unnecessary parentheses
Remove unnecessary parentheses.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-06-04 12:08:06 -05:00
Mika Westerberg 8f004f4a34 ACPI / hotplug / PCI: Mark stale PCI devices disconnected
Following PCIehp mark the unplugged PCI devices disconnected.  This makes
sure PCI core code leaves the now missing hardware registers alone.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
2018-06-04 12:08:06 -05:00
Mika Westerberg 84c8b58ed3 ACPI / hotplug / PCI: Don't scan bridges managed by native hotplug
When acpiphp re-enumerates a PCI hierarchy because of an ACPI Notify()
event, we should skip bridges managed by native hotplug (pciehp or shpchp).
We don't want to scan below a native hotplug bridge until the hotplug
controller generates a hot-add event.

A typical scenario is a Root Port leading to a Thunderbolt host router that
remains powered off until something is connected to it.  See [1] for the
lspci details.

  1. Before something is connected, only the Root Port exists.  It has
     PCI_EXP_SLTCAP_HPC set and pciehp is responsible for hotplug:

       00:1b.0 Root Port (HotPlug+)

  2. When a USB-C or Thunderbolt device is connected, the Switch in the
     Thunderbolt host router is powered up, the Root Port signals a hotplug
     add event and pciehp enumerates the Switch:

       01:00.0 Switch Upstream Port   to [bus 02-39]
       02:00.0 Switch Downstream Port to [bus 03]    (HotPlug-, to NHI)
       02:01.0 Switch Downstream Port to [bus 04-38] (HotPlug+, to Thunderbolt connector)
       02:02.0 Switch Downstream Port to [bus 39]    (HotPlug-, to xHCI)

     The 02:00.0 and 02:02.0 Ports lead to Endpoints that are not powered
     up yet.  The Ports have PCI_EXP_SLTCAP_HPC cleared, so pciehp doesn't
     handle hotplug for them and we assign minimal resources to them.

     The 02:01.0 Port has PCI_EXP_SLTCAP_HPC set, so pciehp handles native
     hotplug events for it.

  3. The BIOS powers up the xHCI controller.  If a Thunderbolt device was
     connected (not just a USB-C device), it also powers up the NHI.  Then
     it sends an ACPI Notify() to the Root Port, and acpiphp enumerates the
     new device(s):

       03:00.0 Thunderbolt Host Controller (NHI) Endpoint
       39:00.0 xHCI Endpoint

  4. If a Thunderbolt device was connected, the host router firmware uses
     the NHI to set up Thunderbolt tunnels and triggers a native hotplug
     event (via 02:01.0 in this example).  Then pciehp enumerates the new
     Thunderbolt devices:

       04:00.0 Switch Upstream Port   to [bus 05-38]
       05:01.0 Switch Downstream Port to [bus 06-09] (HotPlug-)
       05:04.0 Switch Downstream Port to [bus 0a-38] (HotPlug+)

     In this example, 05:01.0 leads to another Switch and some NICs.  This
     subtree is static, so 05:01.0 doesn't support hotplug and has
     PCI_EXP_SLTCAP_HPC cleared.

In step 3, acpiphp previously enumerated everything below the Root Port,
including things below the 02:01.0 Port.  We don't want that because pciehp
expects to manage hotplug below that Port, and firmware on the host router
may be in the middle of configuring its Link so it may not be ready yet.

To make this work better with the native PCIe (pciehp) and standard PCI
(shpchp) hotplug drivers, we let them handle all slot management and
resource allocation for hotplug bridges and restrict ACPI hotplug to
non-hotplug bridges.

[1] https://bugzilla.kernel.org/show_bug.cgi?id=199581#c5
Link: https://lkml.kernel.org/r/20180529160155.1738-1-mika.westerberg@linux.intel.com
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
[bhelgaas: changelog, use hotplug_is_native() instead of
dev->is_hotplug_bridge]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
2018-06-04 12:08:06 -05:00
Mika Westerberg 90cc0c3cc7 PCI: shpchp: Add shpchp_is_native()
In the same way we do for pciehp, add shpchp_is_native(), which returns
true if the bridge should be handled by the native SHPC driver.  Then
convert the driver to use this function.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-06-04 12:08:06 -05:00
Bjorn Helgaas bed4e9cfab PCI: shpchp: Fix AMD POGO identification
The fix for an AMD POGO erratum related to SHPC incorrectly identified the
device.  The workaround should be applied only for AMD POGO devices, but it
was instead applied to:

  - all AMD bridges, and
  - all devices from any vendor with device ID 0x7458

Fixes: 53044f3574 ("[PATCH] PCI Hotplug: shpchp: AMD POGO errata fix")
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-06-04 12:07:31 -05:00
Bjorn Helgaas f2b775f5df PCI: shpchp: Use dev_printk() for OSHP-related messages
Use dev_printk() for messages related to requesting control of SHPC hotplug
via the OSHP method.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-06-02 00:18:28 -05:00
Mika Westerberg 96a621e01a PCI: shpchp: Remove get_hp_hw_control_from_firmware() wrapper
get_hp_hw_control_from_firmware() is a trivial wrapper around
acpi_get_hp_hw_control_from_firmware(), probably intended to be generic in
case other firmware needed similar OS/platform negotiation.

Remove get_hp_hw_control_from_firmware() and call
acpi_get_hp_hw_control_from_firmware() directly.  Add a stub for
acpi_get_hp_hw_control_from_firmware() for the non-ACPI case.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-06-02 00:18:28 -05:00
Mika Westerberg 6f77fa4941 PCI: shpchp: Remove acpi_get_hp_hw_control_from_firmware() flags
acpi_get_hp_hw_control_from_firmware() no longer uses the flags parameter,
so remove it.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
[bhelgaas: split to separate patch]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-06-02 00:18:28 -05:00
Mika Westerberg aa6be07c27 PCI: shpchp: Rely on previous _OSC results
If _OSC exists, we evaluated it when adding the ACPI host bridge, and we
requested SHPC control if the SHPC driver is present.  Use the result of
that _OSC evaluation instead of evaluating it again.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
[bhelgaas: split to separate patch]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-06-02 00:18:28 -05:00
Mika Westerberg 82280f7af7 PCI: shpchp: Convert SHPC to be builtin only
We need to be able coordinate between SHPC and acpiphp to determine which
driver handles hotplug of a given bridge.  Because acpiphp is already bool,
convert SHPC to be bool as well.

Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-06-02 00:18:28 -05:00
Mika Westerberg 13c65840fe PCI: pciehp: Clear Presence Detect and Data Link Layer Status Changed on resume
After a suspend/resume cycle the Presence Detect or Data Link Layer Status
Changed bits might be set.  If we don't clear them those events will not
fire anymore and nothing happens for instance when a device is now
hot-unplugged.

Fix this by clearing those bits in a newly introduced function
pcie_reenable_notification().  This should be fine because immediately
after, we check if the adapter is still present by reading directly from
the status register.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: stable@vger.kernel.org
2018-05-23 17:42:53 -05:00
Julia Lawall 5d9c6b8ae9 PCI: pnv_php: Add missing of_node_put()
The device node iterators perform an of_node_get() on each iteration, so a
jump out of the loop requires an of_node_put().

The semantic patch that fixes this problem is as follows
(http://coccinelle.lip6.fr):

// <smpl>
@@
expression root,e;
local idexpression child;
iterator name for_each_child_of_node;
@@

 for_each_child_of_node(root, child) {
   ... when != of_node_put(child)
       when != e = child
+  of_node_put(child);
?  break;
   ...
}
... when != child
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-05-23 16:48:37 -05:00
Oza Pawandeep 9f5a70f18c PCI: Add generic pcie_wait_for_link() interface
Clients such as hotplug and Downstream Port Containment (DPC) both need to
wait until a link becomes active or inactive.

Add a generic pcie_wait_link_active() interface and use it instead of
duplicating the code.

Signed-off-by: Oza Pawandeep <poza@codeaurora.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
2018-05-17 16:44:11 -05:00
Bjorn Helgaas d22b362184 PCI: pciehp: Add quirk for Command Completed errata
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: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2018-05-07 16:25:08 -05:00
Dan Carpenter 4051f5ebb1 PCI: ibmphp: Fix use-before-set in get_max_bus_speed()
The "rc" variable is only initialized on the error path.  The caller
doesn't check the return but, if "rc" is non-zero, then this function is
basically a no-op.

Fixes: 3749c51ac6 ("PCI: Make current and maximum bus speeds part of the PCI core")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-04-20 12:49:24 -05:00
Linus Torvalds 49a695ba72 powerpc updates for 4.17
Notable changes:
 
  - Support for 4PB user address space on 64-bit, opt-in via mmap().
 
  - Removal of POWER4 support, which was accidentally broken in 2016 and no one
    noticed, and blocked use of some modern instructions.
 
  - Workarounds so that the hypervisor can enable Transactional Memory on Power9.
 
  - A series to disable the DAWR (Data Address Watchpoint Register) on Power9.
 
  - More information displayed in the meltdown/spectre_v1/v2 sysfs files.
 
  - A vpermxor (Power8 Altivec) implementation for the raid6 Q Syndrome.
 
  - A big series to make the allocation of our pacas (per cpu area), kernel page
    tables, and per-cpu stacks NUMA aware when using the Radix MMU on Power9.
 
 And as usual many fixes, reworks and cleanups.
 
 Thanks to:
   Aaro Koskinen, Alexandre Belloni, Alexey Kardashevskiy, Alistair Popple, Andy
   Shevchenko, Aneesh Kumar K.V, Anshuman Khandual, Balbir Singh, Benjamin
   Herrenschmidt, Christophe Leroy, Christophe Lombard, Cyril Bur, Daniel Axtens,
   Dave Young, Finn Thain, Frederic Barrat, Gustavo Romero, Horia Geantă,
   Jonathan Neuschäfer, Kees Cook, Larry Finger, Laurent Dufour, Laurent Vivier,
   Logan Gunthorpe, Madhavan Srinivasan, Mark Greer, Mark Hairgrove, Markus
   Elfring, Mathieu Malaterre, Matt Brown, Matt Evans, Mauricio Faria de
   Oliveira, Michael Neuling, Naveen N. Rao, Nicholas Piggin, Paul Mackerras,
   Philippe Bergheaud, Ram Pai, Rob Herring, Sam Bobroff, Segher Boessenkool,
   Simon Guo, Simon Horman, Stewart Smith, Sukadev Bhattiprolu, Suraj Jitindar
   Singh, Thiago Jung Bauermann, Vaibhav Jain, Vaidyanathan Srinivasan, Vasant
   Hegde, Wei Yongjun.
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Merge tag 'powerpc-4.17-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:
 "Notable changes:

   - Support for 4PB user address space on 64-bit, opt-in via mmap().

   - Removal of POWER4 support, which was accidentally broken in 2016
     and no one noticed, and blocked use of some modern instructions.

   - Workarounds so that the hypervisor can enable Transactional Memory
     on Power9.

   - A series to disable the DAWR (Data Address Watchpoint Register) on
     Power9.

   - More information displayed in the meltdown/spectre_v1/v2 sysfs
     files.

   - A vpermxor (Power8 Altivec) implementation for the raid6 Q
     Syndrome.

   - A big series to make the allocation of our pacas (per cpu area),
     kernel page tables, and per-cpu stacks NUMA aware when using the
     Radix MMU on Power9.

  And as usual many fixes, reworks and cleanups.

  Thanks to: Aaro Koskinen, Alexandre Belloni, Alexey Kardashevskiy,
  Alistair Popple, Andy Shevchenko, Aneesh Kumar K.V, Anshuman Khandual,
  Balbir Singh, Benjamin Herrenschmidt, Christophe Leroy, Christophe
  Lombard, Cyril Bur, Daniel Axtens, Dave Young, Finn Thain, Frederic
  Barrat, Gustavo Romero, Horia Geantă, Jonathan Neuschäfer, Kees Cook,
  Larry Finger, Laurent Dufour, Laurent Vivier, Logan Gunthorpe,
  Madhavan Srinivasan, Mark Greer, Mark Hairgrove, Markus Elfring,
  Mathieu Malaterre, Matt Brown, Matt Evans, Mauricio Faria de Oliveira,
  Michael Neuling, Naveen N. Rao, Nicholas Piggin, Paul Mackerras,
  Philippe Bergheaud, Ram Pai, Rob Herring, Sam Bobroff, Segher
  Boessenkool, Simon Guo, Simon Horman, Stewart Smith, Sukadev
  Bhattiprolu, Suraj Jitindar Singh, Thiago Jung Bauermann, Vaibhav
  Jain, Vaidyanathan Srinivasan, Vasant Hegde, Wei Yongjun"

* tag 'powerpc-4.17-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (207 commits)
  powerpc/64s/idle: Fix restore of AMOR on POWER9 after deep sleep
  powerpc/64s: Fix POWER9 DD2.2 and above in cputable features
  powerpc/64s: Fix pkey support in dt_cpu_ftrs, add CPU_FTR_PKEY bit
  powerpc/64s: Fix dt_cpu_ftrs to have restore_cpu clear unwanted LPCR bits
  Revert "powerpc/64s/idle: POWER9 ESL=0 stop avoid save/restore overhead"
  powerpc: iomap.c: introduce io{read|write}64_{lo_hi|hi_lo}
  powerpc: io.h: move iomap.h include so that it can use readq/writeq defs
  cxl: Fix possible deadlock when processing page faults from cxllib
  powerpc/hw_breakpoint: Only disable hw breakpoint if cpu supports it
  powerpc/mm/radix: Update command line parsing for disable_radix
  powerpc/mm/radix: Parse disable_radix commandline correctly.
  powerpc/mm/hugetlb: initialize the pagetable cache correctly for hugetlb
  powerpc/mm/radix: Update pte fragment count from 16 to 256 on radix
  powerpc/mm/keys: Update documentation and remove unnecessary check
  powerpc/64s/idle: POWER9 ESL=0 stop avoid save/restore overhead
  powerpc/64s/idle: Consolidate power9_offline_stop()/power9_idle_stop()
  powerpc/powernv: Always stop secondaries before reboot/shutdown
  powerpc: hard disable irqs in smp_send_stop loop
  powerpc: use NMI IPI for smp_send_stop
  powerpc/powernv: Fix SMT4 forcing idle code
  ...
2018-04-07 12:08:19 -07:00
Bjorn Helgaas 64ae499cf2 Merge branch 'pci/portdrv'
- move pcieport_if.h to drivers/pci/pcie/ to encapsulate it (Frederick
    Lawler)

  - merge pcieport_if.h into portdrv.h (Bjorn Helgaas)

  - move workaround for BIOS PME issue from portdrv to PCI core (Bjorn
    Helgaas)

  - completely disable portdrv with "pcie_ports=compat" (Bjorn Helgaas)

  - remove portdrv link order dependency (Bjorn Helgaas)

  - remove support for unused VC portdrv service (Bjorn Helgaas)

  - simplify portdrv feature permission checking (Bjorn Helgaas)

  - remove "pcie_hp=nomsi" parameter (use "pci=nomsi" instead) (Bjorn
    Helgaas)

  - remove unnecessary "pcie_ports=auto" parameter (Bjorn Helgaas)

  - use cached AER capability offset (Frederick Lawler)

  - don't enable DPC if BIOS hasn't granted AER control (Mika Westerberg)

  - rename pcie-dpc.c to dpc.c (Bjorn Helgaas)

* pci/portdrv:
  PCI/DPC: Rename from pcie-dpc.c to dpc.c
  PCI/DPC: Do not enable DPC if AER control is not allowed by the BIOS
  PCI/AER: Use cached AER Capability offset
  PCI/portdrv: Rename and reverse sense of pcie_ports_auto
  PCI/portdrv: Encapsulate pcie_ports_auto inside the port driver
  PCI/portdrv: Remove unnecessary "pcie_ports=auto" parameter
  PCI/portdrv: Remove "pcie_hp=nomsi" kernel parameter
  PCI/portdrv: Remove unnecessary include of <linux/pci-aspm.h>
  PCI/portdrv: Simplify PCIe feature permission checking
  PCI/portdrv: Remove unused PCIE_PORT_SERVICE_VC
  PCI/portdrv: Remove pcie_port_bus_type link order dependency
  PCI/portdrv: Disable port driver in compat mode
  PCI/PM: Clear PCIe PME Status bit for Root Complex Event Collectors
  PCI/PM: Clear PCIe PME Status bit in core, not PCIe port driver
  PCI/PM: Move pcie_clear_root_pme_status() to core
  PCI/portdrv: Merge pcieport_if.h into portdrv.h
  PCI/portdrv: Move pcieport_if.h to drivers/pci/pcie/

Conflicts:
	drivers/pci/pcie/Makefile
	drivers/pci/pcie/portdrv.h
2018-04-04 13:27:58 -05:00
Mika Westerberg 13d3047c81 ACPI / hotplug / PCI: Check presence of slot itself in get_slot_status()
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=198557
Reported-by: Mike Lothian <mike@fireburn.co.uk>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org
2018-03-23 16:11:00 -05:00
Simon Guo 97c6f25d58 PCI/hotplug: ppc: correct a php_slot usage after free
In pnv_php_unregister_one(), pnv_php_put_slot() might kfree
php_slot structure. But there is pci_hp_deregister() after
that with php_slot reference.

This patch moves pnv_php_put_slot() to the end of function.

Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-03-13 15:50:32 +11:00
Bjorn Helgaas ef7942603e PCI/portdrv: Merge pcieport_if.h into portdrv.h
pcieport_if.h contained the interfaces to register port service driver,
e.g., pcie_port_service_register().  portdrv.h contained internal data
structures of the port driver.

I don't think it's worth keeping those files separate, since both headers
and their users are all inside the PCI core.

Merge pcieport_if.h directly in drivers/pci/pcie/portdrv.h and update the
users to include that instead.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2018-03-09 11:42:01 -06:00
Shawn Lin 205adda79a PCI: cpqphp: Fix possible NULL pointer dereference
Check io_node for NULL before dereferencing it.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>
2018-02-28 14:35:54 -06:00
Frederick Lawler c37e627f95 PCI/portdrv: Move pcieport_if.h to drivers/pci/pcie/
Move pcieport_if.h from include/linux to drivers/pci/pcie/pcieport_if.h
because the interfaces there are only used by the PCI core.

Replace all uses of #include<linux/pcieport_if.h> with relative paths to
the new file location, e.g., #include "../pcieport_if.h"

Signed-off-by: Frederick Lawler <fred@fredlawl.com>
Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>
2018-02-22 17:14:36 -06:00