The ACPI specification (ACPI 5.0A, Section 6.3.7) says:
_STA may return bit 0 clear (not present) with bit 3 set (device is
functional). This case is used to indicate a valid device for which
no device driver should be loaded (for example, a bridge device.)
Children of this device may be present and valid. OSPM should
continue enumeration below a device whose _STA returns this bit
combination.
Evidently, some BIOSes follow that and return 0x0A from _STA, which
causes problems to happen when they trigger bus check or device check
notifications for those devices too. Namely, ACPIPHP thinks that they
are gone and may drop them, for example, if such a notification is
triggered during a resume from system suspend.
To fix that, modify ACPICA to regard devies as present and
functioning if _STA returns both the ACPI_STA_DEVICE_ENABLED
and ACPI_STA_DEVICE_FUNCTIONING bits set for them.
Reported-and-tested-by: Peter Wu <lekensteyn@gmail.com>
Cc: 3.12+ <stable@vger.kernel.org> # 3.12+
[rjw: Subject and changelog, minor code modifications]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
If a PCI bridge with an ACPIPHP context attached is removed via
sysfs, the code path executed as a result is the following:
pci_stop_and_remove_bus_device_locked
pci_remove_bus
pcibios_remove_bus
acpi_pci_remove_bus
acpiphp_remove_slots
cleanup_bridge
unregister_hotplug_dock_device (drops dock references to the bridge)
put_bridge
free_bridge
acpiphp_put_context (for each child, under context lock)
kfree (context)
Now, if a dock event affecting one of the bridge's child devices
occurs (roughly at the same time), it will lead to the following code
path:
acpi_dock_deferred_cb
dock_notify
handle_eject_request
hot_remove_dock_devices
dock_hotplug_event
hotplug_event (dereferences context)
That may lead to a kernel crash in hotplug_event() if it is executed
after the last kfree() in the bridge removal code path.
To prevent that from happening, add a wrapper around hotplug_event()
called dock_event() and point the .handler pointer in acpiphp_dock_ops
to it. Make that wrapper retrieve the device's ACPIPHP context using
acpiphp_get_context() (instead of taking it from the data argument)
under acpiphp_context_lock and check if the parent bridge's
is_going_away flag is set. If that flag is set, it will return
immediately and if it is not set it will grab a reference to the
device's parent bridge before executing hotplug_event().
Then, in the above scenario, the reference to the parent bridge
held by dock_event() will prevent free_bridge() from being executed
for it until hotplug_event() returns.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
If a PCI bridge with an ACPIPHP context attached is removed via
sysfs, the code path executed as a result is the following:
pci_stop_and_remove_bus_device_locked
pci_remove_bus
pcibios_remove_bus
acpi_pci_remove_bus
acpiphp_remove_slots
cleanup_bridge
put_bridge
free_bridge
acpiphp_put_context (for each child, under context lock)
kfree (child context)
Now, if a hotplug notify is dispatched for one of the bridge's
children and the timing is such that handle_hotplug_event() for
that notify is executed while free_bridge() above is running,
the get_bridge(context->func.parent) in handle_hotplug_event()
will not really help, because it is too late to prevent the bridge
from going away and the child's context may be freed before
hotplug_event_work() scheduled from handle_hotplug_event()
dereferences the pointer to it passed via the data argument.
That will cause a kernel crash to happpen in hotplug_event_work().
To prevent that from happening, make handle_hotplug_event()
check the is_going_away flag of the function's parent bridge
(under acpiphp_context_lock) and bail out if it's set. Also,
make cleanup_bridge() set the bridge's is_going_away flag under
acpiphp_context_lock so that it cannot be changed between the
check and the subsequent get_bridge(context->func.parent) in
handle_hotplug_event().
Then, in the above scenario, handle_hotplug_event() will notice
that context->func.parent->is_going_away is already set and it
will exit immediately preventing the crash from happening.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Since acpiphp_check_bridge() called by acpiphp_check_host_bridge()
does things that require PCI rescan-remove locking around it,
make acpiphp_check_host_bridge() use that locking.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Commit 9217a98467 (ACPI / hotplug / PCI: Use global PCI rescan-remove
locking) modified ACPIPHP to protect its PCI device removal and addition
code paths from races against sysfs-driven rescan and remove operations
with the help of PCI rescan-remove locking. However, it overlooked the
fact that hotplug_event_work() is not the only caller of hotplug_event()
which may also be called by dock_hotplug_event() and that code path
is missing the PCI rescan-remove locking. This means that, although
the PCI rescan-remove lock is held as appropriate during the handling
of events originating from handle_hotplug_event(), the ACPIPHP's
operations resulting from dock events may still suffer the race
conditions that commit 9217a98467 was supposed to eliminate.
To address that problem, move the PCI rescan-remove locking from
hotplug_event_work() to hotplug_event() so that it is used regardless
of the way that function is invoked.
Revamps: 9217a98467 (ACPI / hotplug / PCI: Use global PCI rescan-remove locking)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
According to the changelog of commit 29ed1f29b6 (PCI: pciehp: Fix null
pointer deref when hot-removing SR-IOV device) it is unsafe to walk the
bus->devices list of a PCI bus and remove devices from it in direct order,
because that may lead to NULL pointer dereferences related to virtual
functions.
For this reason, change all of the bus->devices list walks in
acpiphp_glue.c during which devices may be removed to be carried out in
reverse order.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Revert commit ef83b0781a "PCI: Remove from bus_list and release
resources in pci_release_dev()" that made some nasty race conditions
become possible. For example, if a Thunderbolt link is unplugged
and then replugged immediately, the pci_release_dev() resulting from
the hot-remove code path may be racing with the hot-add code path
which after that commit causes various kinds of breakage to happen
(up to and including a hard crash of the whole system).
Moreover, the problem that commit ef83b0781a attempted to address
cannot happen any more after commit 8a4c5c329d "PCI: Check parent
kobject in pci_destroy_dev()", because pci_destroy_dev() will now
return immediately if it has already been executed for the given
device.
Note, however, that the invocation of msi_remove_pci_irq_vectors()
removed by commit ef83b0781a from pci_free_resources() along with
the other changes made by it is not added back because of subsequent
code changes depending on that modification.
Fixes: ef83b0781a (PCI: Remove from bus_list and release resources in pci_release_dev())
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- ACPI core changes to make it create a struct acpi_device object for every
device represented in the ACPI tables during all namespace scans regardless
of the current status of that device. In accordance with this, ACPI hotplug
operations will not delete those objects, unless the underlying ACPI tables
go away.
- On top of the above, new sysfs attribute for ACPI device objects allowing
user space to check device status by triggering the execution of _STA for
its ACPI object. From Srinivas Pandruvada.
- ACPI core hotplug changes reducing code duplication, integrating the
PCI root hotplug with the core and reworking container hotplug.
- ACPI core simplifications making it use ACPI_COMPANION() in the code
"glueing" ACPI device objects to "physical" devices.
- ACPICA update to upstream version 20131218. This adds support for the
DBG2 and PCCT tables to ACPICA, fixes some bugs and improves debug
facilities. From Bob Moore, Lv Zheng and Betty Dall.
- Init code change to carry out the early ACPI initialization earlier.
That should allow us to use ACPI during the timekeeping initialization
and possibly to simplify the EFI initialization too. From Chun-Yi Lee.
- Clenups of the inclusions of ACPI headers in many places all over from
Lv Zheng and Rashika Kheria (work in progress).
- New helper for ACPI _DSM execution and rework of the code in drivers
that uses _DSM to execute it via the new helper. From Jiang Liu.
- New Win8 OSI blacklist entries from Takashi Iwai.
- Assorted ACPI fixes and cleanups from Al Stone, Emil Goode, Hanjun Guo,
Lan Tianyu, Masanari Iida, Oliver Neukum, Prarit Bhargava, Rashika Kheria,
Tang Chen, Zhang Rui.
- intel_pstate driver updates, including proper Baytrail support, from
Dirk Brandewie and intel_pstate documentation from Ramkumar Ramachandra.
- Generic CPU boost ("turbo") support for cpufreq from Lukasz Majewski.
- powernow-k6 cpufreq driver fixes from Mikulas Patocka.
- cpufreq core fixes and cleanups from Viresh Kumar, Jane Li, Mark Brown.
- Assorted cpufreq drivers fixes and cleanups from Anson Huang, John Tobias,
Paul Bolle, Paul Walmsley, Sachin Kamat, Shawn Guo, Viresh Kumar.
- cpuidle cleanups from Bartlomiej Zolnierkiewicz.
- Support for hibernation APM events from Bin Shi.
- Hibernation fix to avoid bringing up nonboot CPUs with ACPI EC disabled
during thaw transitions from Bjørn Mork.
- PM core fixes and cleanups from Ben Dooks, Leonardo Potenza, Ulf Hansson.
- PNP subsystem fixes and cleanups from Dmitry Torokhov, Levente Kurusa,
Rashika Kheria.
- New tool for profiling system suspend from Todd E Brandt and a cpupower
tool cleanup from One Thousand Gnomes.
/
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Merge tag 'pm+acpi-3.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI and power management updates from Rafael Wysocki:
"As far as the number of commits goes, the top spot belongs to ACPI
this time with cpufreq in the second position and a handful of PM
core, PNP and cpuidle updates. They are fixes and cleanups mostly, as
usual, with a couple of new features in the mix.
The most visible change is probably that we will create struct
acpi_device objects (visible in sysfs) for all devices represented in
the ACPI tables regardless of their status and there will be a new
sysfs attribute under those objects allowing user space to check that
status via _STA.
Consequently, ACPI device eject or generally hot-removal will not
delete those objects, unless the table containing the corresponding
namespace nodes is unloaded, which is extremely rare. Also ACPI
container hotplug will be handled quite a bit differently and cpufreq
will support CPU boost ("turbo") generically and not only in the
acpi-cpufreq driver.
Specifics:
- ACPI core changes to make it create a struct acpi_device object for
every device represented in the ACPI tables during all namespace
scans regardless of the current status of that device. In
accordance with this, ACPI hotplug operations will not delete those
objects, unless the underlying ACPI tables go away.
- On top of the above, new sysfs attribute for ACPI device objects
allowing user space to check device status by triggering the
execution of _STA for its ACPI object. From Srinivas Pandruvada.
- ACPI core hotplug changes reducing code duplication, integrating
the PCI root hotplug with the core and reworking container hotplug.
- ACPI core simplifications making it use ACPI_COMPANION() in the
code "glueing" ACPI device objects to "physical" devices.
- ACPICA update to upstream version 20131218. This adds support for
the DBG2 and PCCT tables to ACPICA, fixes some bugs and improves
debug facilities. From Bob Moore, Lv Zheng and Betty Dall.
- Init code change to carry out the early ACPI initialization
earlier. That should allow us to use ACPI during the timekeeping
initialization and possibly to simplify the EFI initialization too.
From Chun-Yi Lee.
- Clenups of the inclusions of ACPI headers in many places all over
from Lv Zheng and Rashika Kheria (work in progress).
- New helper for ACPI _DSM execution and rework of the code in
drivers that uses _DSM to execute it via the new helper. From
Jiang Liu.
- New Win8 OSI blacklist entries from Takashi Iwai.
- Assorted ACPI fixes and cleanups from Al Stone, Emil Goode, Hanjun
Guo, Lan Tianyu, Masanari Iida, Oliver Neukum, Prarit Bhargava,
Rashika Kheria, Tang Chen, Zhang Rui.
- intel_pstate driver updates, including proper Baytrail support,
from Dirk Brandewie and intel_pstate documentation from Ramkumar
Ramachandra.
- Generic CPU boost ("turbo") support for cpufreq from Lukasz
Majewski.
- powernow-k6 cpufreq driver fixes from Mikulas Patocka.
- cpufreq core fixes and cleanups from Viresh Kumar, Jane Li, Mark
Brown.
- Assorted cpufreq drivers fixes and cleanups from Anson Huang, John
Tobias, Paul Bolle, Paul Walmsley, Sachin Kamat, Shawn Guo, Viresh
Kumar.
- cpuidle cleanups from Bartlomiej Zolnierkiewicz.
- Support for hibernation APM events from Bin Shi.
- Hibernation fix to avoid bringing up nonboot CPUs with ACPI EC
disabled during thaw transitions from Bjørn Mork.
- PM core fixes and cleanups from Ben Dooks, Leonardo Potenza, Ulf
Hansson.
- PNP subsystem fixes and cleanups from Dmitry Torokhov, Levente
Kurusa, Rashika Kheria.
- New tool for profiling system suspend from Todd E Brandt and a
cpupower tool cleanup from One Thousand Gnomes"
* tag 'pm+acpi-3.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (153 commits)
thermal: exynos: boost: Automatic enable/disable of BOOST feature (at Exynos4412)
cpufreq: exynos4x12: Change L0 driver data to CPUFREQ_BOOST_FREQ
Documentation: cpufreq / boost: Update BOOST documentation
cpufreq: exynos: Extend Exynos cpufreq driver to support boost
cpufreq / boost: Kconfig: Support for software-managed BOOST
acpi-cpufreq: Adjust the code to use the common boost attribute
cpufreq: Add boost frequency support in core
intel_pstate: Add trace point to report internal state.
cpufreq: introduce cpufreq_generic_get() routine
ARM: SA1100: Create dummy clk_get_rate() to avoid build failures
cpufreq: stats: create sysfs entries when cpufreq_stats is a module
cpufreq: stats: free table and remove sysfs entry in a single routine
cpufreq: stats: remove hotplug notifiers
cpufreq: stats: handle cpufreq_unregister_driver() and suspend/resume properly
cpufreq: speedstep: remove unused speedstep_get_state
platform: introduce OF style 'modalias' support for platform bus
PM / tools: new tool for suspend/resume performance optimization
ACPI: fix module autoloading for ACPI enumerated devices
ACPI: add module autoloading support for ACPI enumerated devices
ACPI: fix create_modalias() return value handling
...
This is the branch where we usually queue up cleanup efforts, moving
drivers out of the architecture directory, header file restructuring,
etc. Sometimes they tangle with new development so it's hard to keep it
strictly to cleanups.
Some of the things included in this branch are:
* Atmel SAMA5 conversion to common clock
* Reset framework conversion for tegra platforms
- Some of this depends on tegra clock driver reworks that are shared with Mike
Turquette's clk tree.
* Tegra DMA refactoring, which are shared branches with the DMA tree.
* Removal of some header files on exynos to prepare for multiplatform
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Merge tag 'cleanup-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC cleanups from Olof Johansson:
"This is the branch where we usually queue up cleanup efforts, moving
drivers out of the architecture directory, header file restructuring,
etc. Sometimes they tangle with new development so it's hard to keep
it strictly to cleanups.
Some of the things included in this branch are:
* Atmel SAMA5 conversion to common clock
* Reset framework conversion for tegra platforms
- Some of this depends on tegra clock driver reworks that are shared
with Mike Turquette's clk tree.
* Tegra DMA refactoring, which are shared branches with the DMA tree.
* Removal of some header files on exynos to prepare for
multiplatform"
* tag 'cleanup-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (169 commits)
ARM: mvebu: move Armada 370/XP specific definitions to armada-370-xp.h
ARM: mvebu: remove prototypes of non-existing functions from common.h
ARM: mvebu: move ARMADA_XP_MAX_CPUS to armada-370-xp.h
serial: sh-sci: Rework baud rate calculation
serial: sh-sci: Compute overrun_bit without using baud rate algo
serial: sh-sci: Remove unused GPIO request code
serial: sh-sci: Move overrun_bit and error_mask fields out of pdata
serial: sh-sci: Support resources passed through platform resources
serial: sh-sci: Don't check IRQ in verify port operation
serial: sh-sci: Set the UPF_FIXED_PORT flag
serial: sh-sci: Remove duplicate interrupt check in verify port op
serial: sh-sci: Simplify baud rate calculation algorithms
serial: sh-sci: Remove baud rate calculation algorithm 5
serial: sh-sci: Sort headers alphabetically
ARM: EXYNOS: Kill exynos_pm_late_initcall()
ARM: EXYNOS: Consolidate selection of PM_GENERIC_DOMAINS for Exynos4
ARM: at91: switch Calao QIL-A9260 board to DT
clk: at91: fix pmc_clk_ids data type attriubte
PM / devfreq: use inclusion <mach/map.h> instead of <plat/map-s5p.h>
ARM: EXYNOS: remove <mach/regs-clock.h> for exynos
...
- FIFO event channels. Key advantages: support for over 100,000 events (2^17),
16 different event priorities, improved fairness in event latency through
the use of FIFOs.
- Xen PVH support. "It’s a fully PV kernel mode, running with paravirtualized
disk and network, paravirtualized interrupts and timers, no emulated devices
of any kind (and thus no qemu), no BIOS or legacy boot — but instead of
requiring PV MMU, it uses the HVM hardware extensions to virtualize the
pagetables, as well as system calls and other privileged operations."
(from "The Paravirtualization Spectrum, Part 2: From poles to a spectrum")
Bug-fixes:
- Fixes in balloon driver (refactor and make it work under ARM)
- Allow xenfb to be used in HVM guests.
- Allow xen_platform_pci=0 to work properly.
- Refactors in event channels.
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Merge tag 'stable/for-linus-3.14-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull Xen updates from Konrad Rzeszutek Wilk:
"Two major features that Xen community is excited about:
The first is event channel scalability by David Vrabel - we switch
over from an two-level per-cpu bitmap of events (IRQs) - to an FIFO
queue with priorities. This lets us be able to handle more events,
have lower latency, and better scalability. Good stuff.
The other is PVH by Mukesh Rathor. In short, PV is a mode where the
kernel lets the hypervisor program page-tables, segments, etc. With
EPT/NPT capabilities in current processors, the overhead of doing this
in an HVM (Hardware Virtual Machine) container is much lower than the
hypervisor doing it for us.
In short we let a PV guest run without doing page-table, segment,
syscall, etc updates through the hypervisor - instead it is all done
within the guest container. It is a "hybrid" PV - hence the 'PVH'
name - a PV guest within an HVM container.
The major benefits are less code to deal with - for example we only
use one function from the the pv_mmu_ops (which has 39 function
calls); faster performance for syscall (no context switches into the
hypervisor); less traps on various operations; etc.
It is still being baked - the ABI is not yet set in stone. But it is
pretty awesome and we are excited about it.
Lastly, there are some changes to ARM code - you should get a simple
conflict which has been resolved in #linux-next.
In short, this pull has awesome features.
Features:
- FIFO event channels. Key advantages: support for over 100,000
events (2^17), 16 different event priorities, improved fairness in
event latency through the use of FIFOs.
- Xen PVH support. "It’s a fully PV kernel mode, running with
paravirtualized disk and network, paravirtualized interrupts and
timers, no emulated devices of any kind (and thus no qemu), no BIOS
or legacy boot — but instead of requiring PV MMU, it uses the HVM
hardware extensions to virtualize the pagetables, as well as system
calls and other privileged operations." (from "The
Paravirtualization Spectrum, Part 2: From poles to a spectrum")
Bug-fixes:
- Fixes in balloon driver (refactor and make it work under ARM)
- Allow xenfb to be used in HVM guests.
- Allow xen_platform_pci=0 to work properly.
- Refactors in event channels"
* tag 'stable/for-linus-3.14-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (52 commits)
xen/pvh: Set X86_CR0_WP and others in CR0 (v2)
MAINTAINERS: add git repository for Xen
xen/pvh: Use 'depend' instead of 'select'.
xen: delete new instances of __cpuinit usage
xen/fb: allow xenfb initialization for hvm guests
xen/evtchn_fifo: fix error return code in evtchn_fifo_setup()
xen-platform: fix error return code in platform_pci_init()
xen/pvh: remove duplicated include from enlighten.c
xen/pvh: Fix compile issues with xen_pvh_domain()
xen: Use dev_is_pci() to check whether it is pci device
xen/grant-table: Force to use v1 of grants.
xen/pvh: Support ParaVirtualized Hardware extensions (v3).
xen/pvh: Piggyback on PVHVM XenBus.
xen/pvh: Piggyback on PVHVM for grant driver (v4)
xen/grant: Implement an grant frame array struct (v3).
xen/grant-table: Refactor gnttab_init
xen/grants: Remove gnttab_max_grant_frames dependency on gnttab_init.
xen/pvh: Piggyback on PVHVM for event channels (v2)
xen/pvh: Update E820 to work with PVH (v2)
xen/pvh: Secondary VCPU bringup (non-bootup CPUs)
...
* pci/locking:
PCI: Check parent kobject in pci_destroy_dev()
xen/pcifront: Use global PCI rescan-remove locking
powerpc/eeh: Use global PCI rescan-remove locking
MPT / PCI: Use pci_stop_and_remove_bus_device_locked()
platform / x86: Use global PCI rescan-remove locking
PCI: hotplug: Use global PCI rescan-remove locking
pcmcia: Use global PCI rescan-remove locking
ACPI / hotplug / PCI: Use global PCI rescan-remove locking
ACPI / PCI: Use global PCI rescan-remove locking in PCI root hotplug
PCI: Add global pci_lock_rescan_remove()
If pci_stop_and_remove_bus_device() is run concurrently for a device and
its parent bridge via remove_callback(), both code paths attempt to acquire
pci_rescan_remove_lock. If the child device removal acquires it first,
there will be no problems. However, if the parent bridge removal acquires
it first, it will eventually execute pci_destroy_dev() for the child
device, but that device object will not be freed yet due to the reference
held by the concurrent child removal. Consequently, both
pci_stop_bus_device() and pci_remove_bus_device() will be executed for that
device unnecessarily and pci_destroy_dev() will see a corrupted list head
in that object. Moreover, an excess put_device() will be executed for that
device in that case which may lead to a use-after-free in the final
kobject_put() done by sysfs_schedule_callback_work().
To avoid that problem, make pci_destroy_dev() check if the device's parent
kobject is NULL, which only happens after device_del() has already run for
it. Make pci_destroy_dev() return immediately whithout doing anything in
that case.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Multiple race conditions are possible between the Xen pcifront device
addition and removal and the generic PCI device addition and removal that
can be triggered via sysfs.
To avoid those race conditions make the Xen pcifront code use global PCI
rescan-remove locking.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
When doing a function/slot/bus reset PCI grabs the device_lock for each
device to block things like suspend and driver probes, but call paths exist
where this lock may already be held. This creates an opportunity for
deadlock. For instance, vfio allows userspace to issue resets so long as
it owns the device(s). If a driver unbind .remove callback races with
userspace issuing a reset, we have a deadlock as userspace gets stuck
waiting on device_lock while another thread has device_lock and waits for
.remove to complete. To resolve this, we can make a version of the reset
interfaces which use trylock. With this, we can safely attempt a reset and
return error to userspace if there is contention.
[bhelgaas: the deadlock happens when A (userspace) has a file descriptor for
the device, and B waits in this path:
driver_detach
device_lock # take device_lock
__device_release_driver
pci_device_remove # pci_bus_type.remove
vfio_pci_remove # pci_driver .remove
vfio_del_group_dev
wait_event(vfio.release_q, !vfio_dev_present) # wait (holding device_lock)
Now B is stuck until A gives up the file descriptor. If A tries to acquire
device_lock for any reason, we deadlock because A is waiting for B to release
the lock, and B is waiting for A to release the file descriptor.]
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Multiple race conditions are possible between PCI hotplug and the generic
PCI bus rescan and device removal that can be triggered via sysfs.
To avoid those race conditions make PCI hotplug use global PCI
rescan-remove locking.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Multiple race conditions are possible between the ACPI-based PCI hotplug
(ACPIPHP) and the generic PCI bus rescan and device removal that can be
triggered via sysfs.
To avoid those race conditions make the ACPIPHP code use global PCI
rescan-remove locking.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
There are multiple PCI device addition and removal code paths that may be
run concurrently with the generic PCI bus rescan and device removal that
can be triggered via sysfs. If that happens, it may lead to multiple
different, potentially dangerous race conditions.
The most straightforward way to address those problems is to run
the code in question under the same lock that is used by the
generic rescan/remove code in pci-sysfs.c. To prepare for those
changes, move the definition of the global PCI remove/rescan lock
to probe.c and provide global wrappers, pci_lock_rescan_remove()
and pci_unlock_rescan_remove(), allowing drivers to manipulate
that lock. Also provide pci_stop_and_remove_bus_device_locked()
for the callers of pci_stop_and_remove_bus_device() who only need
to hold the rescan/remove lock around it.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Consistently use the:
#ifdef CONFIG_PCI_FOO
int pci_foo(...);
#else
static inline int pci_foo(...) { return -1; }
#endif
pattern, instead of sometimes using "#ifndef CONFIG_PCI_FOO".
No functional change.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
* pci/aer:
PCI/AER: Support ACPI HEST AER error sources for PCI domains other than 0
ACPICA: Add helper macros to extract bus/segment numbers from HEST table.
In the discussion for this set of patches [link below], Bjorn Helgaas
pointed out that the ACPI HEST AER error sources do not have the PCIe
segment number associated with the bus. I worked with the ACPI spec and
got this change to definition of the "Bus" field into the recently released
ACPI Spec 5.0a section 18.3.2.3-5:
Identifies the PCI Bus and Segment of the device. The Bus is encoded in
bits 0-7. For systems that expose multiple PCI segment groups, the
segment number is encoded in bits 8-23 and bits 24-31 must be zero. For
systems that do not expose multiple PCI segment groups, bits 8-31 must be
zero. If the GLOBAL flag is specified, this field is ignored.
This patch makes use of the new definition in the only place in the kernel
that uses the acpi_hest_aer_common's bus field.
This depends on 36f3615152 ("ACPICA: Add helper macros to extract
bus/segment numbers from HEST table.")
Link: http://lkml.kernel.org/r/1370542251-27387-1-git-send-email-betty.dall@hp.com
Signed-off-by: Betty Dall <betty.dall@hp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Using 'make namespacecheck' identify code which should be declared static.
Checked for users in other driver/archs as well. Compile tested only.
This stops exporting the following interfaces to modules:
pci_target_state()
pci_load_saved_state()
[bhelgaas: retained pci_find_next_ext_capability() and pci_cfg_space_size()]
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
My philosophy is unused code is dead code. And dead code is subject to bit
rot and is a likely source of bugs. Use it or lose it.
This removes this unused and deprecated interface:
alloc_pci_dev()
[bhelgaas: split to separate patch]
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
My philosophy is unused code is dead code. And dead code is subject to bit
rot and is a likely source of bugs. Use it or lose it.
This reverts part of f46753c5e3 ("PCI: introduce pci_slot") and
d25b7c8d6b ("PCI: rename pci_update_slot_number to pci_renumber_slot"),
removing this interface:
pci_renumber_slot()
[bhelgaas: split to separate patch, add historical link from Alex]
Link: http://lkml.kernel.org/r/20081009043140.8678.44164.stgit@bob.kio
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Alex Chiang <achiang@canonical.com>
My philosophy is unused code is dead code. And dead code is subject to bit
rot and is a likely source of bugs. Use it or lose it.
This reverts part of 3e1b16002a ("ACPI/PCI: PCIe ASPM _OSC support
capabilities called when root bridge added"), removing this interface:
pcie_aspm_enabled()
[bhelgaas: split to separate patch]
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Andrew Patterson <andrew.patterson@hp.com>
My philosophy is unused code is dead code. And dead code is subject to bit
rot and is a likely source of bugs. Use it or lose it.
This reverts db5679437a ("PCI: add interface to set visible size of
VPD"), removing this interface:
pci_vpd_truncate()
[bhelgaas: split to separate patch, also remove prototype from pci.h]
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
* acpi-cleanup: (22 commits)
ACPI / tables: Return proper error codes from acpi_table_parse() and fix comment.
ACPI / tables: Check if id is NULL in acpi_table_parse()
ACPI / proc: Include appropriate header file in proc.c
ACPI / EC: Remove unused functions and add prototype declaration in internal.h
ACPI / dock: Include appropriate header file in dock.c
ACPI / PCI: Include appropriate header file in pci_link.c
ACPI / PCI: Include appropriate header file in pci_slot.c
ACPI / EC: Mark the function acpi_ec_add_debugfs() as static in ec_sys.c
ACPI / NVS: Include appropriate header file in nvs.c
ACPI / OSL: Mark the function acpi_table_checksum() as static
ACPI / processor: initialize a variable to silence compiler warning
ACPI / processor: use ACPI_COMPANION() to get ACPI device
ACPI: correct minor typos
ACPI / sleep: Drop redundant acpi_disabled check
ACPI / dock: Drop redundant acpi_disabled check
ACPI / table: Replace '1' with specific error return values
ACPI: remove trailing whitespace
ACPI / IBFT: Fix incorrect <acpi/acpi.h> inclusion in iSCSI boot firmware module
ACPI / i915: Fix incorrect <acpi/acpi.h> inclusions via <linux/acpi_io.h>
SFI / ACPI: Fix warnings reported during builds with W=1
...
Conflicts:
drivers/acpi/nvs.c
drivers/hwmon/asus_atk0110.c
My philosophy is unused code is dead code. And dead code is subject to bit
rot and is a likely source of bugs. Use it or lose it.
This reverts b48d4425b6 ("PCI: add ID-based ordering enable/disable
support"), removing these interfaces:
pci_enable_ido()
pci_disable_ido()
[bhelgaas: split to separate patch, also remove prototypes from pci.h]
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Jesse Barnes <jbarnes@virtuousgeek.org>
My philosophy is unused code is dead code. And dead code is subject to bit
rot and is a likely source of bugs. Use it or lose it.
This reverts 48a92a8179 ("PCI: add OBFF enable/disable support"),
removing these interfaces:
pci_enable_obff()
pci_disable_obff()
[bhelgaas: split to separate patch, also remove prototypes from pci.h]
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Jesse Barnes <jbarnes@virtuousgeek.org>
My philosophy is unused code is dead code. And dead code is subject to bit
rot and is a likely source of bugs. Use it or lose it.
This reverts 51c2e0a7e5 ("PCI: add latency tolerance reporting
enable/disable support"), removing these interfaces:
pci_enable_ltr()
pci_disable_ltr()
pci_set_ltr()
[bhelgaas: split to separate patch, also remove prototypes from pci.h]
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Jesse Barnes <jbarnes@virtuousgeek.org>
* pci/resource:
PCI: Allocate 64-bit BARs above 4G when possible
PCI: Enforce bus address limits in resource allocation
PCI: Split out bridge window override of minimum allocation address
agp/ati: Use PCI_COMMAND instead of hard-coded 4
agp/intel: Use CPU physical address, not bus address, for ioremap()
agp/intel: Use pci_bus_address() to get GTTADR bus address
agp/intel: Use pci_bus_address() to get MMADR bus address
agp/intel: Support 64-bit GMADR
agp/intel: Rename gtt_bus_addr to gtt_phys_addr
drm/i915: Rename gtt_bus_addr to gtt_phys_addr
agp: Use pci_resource_start() to get CPU physical address for BAR
agp: Support 64-bit APBASE
PCI: Add pci_bus_address() to get bus address of a BAR
PCI: Convert pcibios_resource_to_bus() to take a pci_bus, not a pci_dev
PCI: Change pci_bus_region addresses to dma_addr_t
My philosophy is unused code is dead code. And dead code is subject to bit
rot and is a likely source of bugs. Use it or lose it.
This reverts parts of c320b976d7 ("PCI: Add implementation for PRI
capability"), removing these interfaces:
pci_pri_enabled()
pci_pri_stopped()
pci_pri_status()
[bhelgaas: split to separate patch]
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Joerg Roedel <joro@8bytes.org>
Per the SR-IOV spec rev 1.1:
3.4.1.9 Header Type (Offset 0Eh)
"... For VFs, this register must be RO Zero."
Unfortunately some devices get this wrong, ex. Emulex OneConnect 10Gb NIC.
When they do it makes us handle ACS testing and therefore IOMMU groups as
if they were actual multifunction devices and require ACS capabilities to
make sure there's no peer-to-peer between functions. VFs are never
traditional multifunction devices, so simply clear this bit before we get
any further into setup.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=68431
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Try to allocate space for 64-bit BARs above 4G first, to preserve the space
below 4G for 32-bit BARs. If there's no space above 4G available, fall
back to allocating anywhere.
[bhelgaas: reworked starting from http://lkml.kernel.org/r/1387485843-17403-2-git-send-email-yinghai@kernel.org]
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
When allocating space for 32-bit BARs, we previously limited RESOURCE
addresses so they would fit in 32 bits. However, the BUS address need not
be the same as the resource address, and it's the bus address that must fit
in the 32-bit BAR.
This patch adds:
- pci_clip_resource_to_region(), which clips a resource so it contains
only the range that maps to the specified bus address region, e.g., to
clip a resource to 32-bit bus addresses, and
- pci_bus_alloc_from_region(), which allocates space for a resource from
the specified bus address region,
and changes pci_bus_alloc_resource() to allocate space for 64-bit BARs from
the entire bus address region, and space for 32-bit BARs from only the bus
address region below 4GB.
If we had this window:
pci_root HWP0002:0a: host bridge window [mem 0xf0180000000-0xf01fedfffff] (bus address [0x80000000-0xfedfffff])
we previously could not put a 32-bit BAR there, because the CPU addresses
don't fit in 32 bits. This patch fixes this, so we can use this space for
32-bit BARs.
It's also possible (though unlikely) to have resources with 32-bit CPU
addresses but bus addresses above 4GB. In this case the previous code
would allocate space that a 32-bit BAR could not map.
Remove PCIBIOS_MAX_MEM_32, which is no longer used.
[bhelgaas: reworked starting from http://lkml.kernel.org/r/1386658484-15774-3-git-send-email-yinghai@kernel.org]
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
pci_bus_alloc_resource() avoids allocating space below the "min" supplied
by the caller (usually PCIBIOS_MIN_IO or PCIBIOS_MIN_MEM). This is to
protect badly documented motherboard resources. But if we're allocating
space inside an already-configured PCI-PCI bridge window, we ignore "min".
See 688d191821 ("pci: make bus resource start address override minimum IO
address").
This patch moves the check to make it more visible and simplify future
patches. No functional change.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Current pci-label driver detects ACPI label by checking label index
returned by ACPI _DSM method, and treats it as valid if label index
is positive. According to ACPI Firmware specification 3.1, zero is
also an valid label index. So change code to detect availability of
ACPI slot label by checking availaiblity of ACPI _DSM function for
PCI label.
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Use helper functions to simplify _DSM related code in pci-label driver.
Also enforce more strict checks on objects returned by _DSM method.
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Function dsm_get_label() leaks the returned ACPI object if
obj->package.count is not 2, so fix the possible memory leak.
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This adds pci_enable_msi_range(), which supersedes the pci_enable_msi()
and pci_enable_msi_block() MSI interfaces.
It also adds pci_enable_msix_range(), which supersedes the
pci_enable_msix() MSI-X interface.
The old interfaces have three categories of return values:
negative: failure; caller should not retry
positive: failure; value indicates number of interrupts that *could*
have been allocated, and caller may retry with a smaller request
zero: success; at least as many interrupts allocated as requested
It is error-prone to handle these three cases correctly in drivers.
The new functions return either a negative error code or a number of
successfully allocated MSI/MSI-X interrupts, which is expected to lead to
clearer device driver code.
pci_enable_msi(), pci_enable_msi_block() and pci_enable_msix() still exist
unchanged, but are deprecated and may be removed after callers are updated.
[bhelgaas: tweak changelog]
Suggested-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Mika Westerberg
Rafael J. Wysocki
Linus Torvalds
Bjorn Helgaas
Alex Williamson
Betty Dall
Stephen Hemminger
Yinghai Lu
Jiang Liu
Alexander Gordeev