ACPI / hotplug / PCI: Rework acpiphp_check_host_bridge()

Since the only existing caller of acpiphp_check_host_bridge(),
which is acpi_pci_root_scan_dependent(), already has a struct
acpi_device poin

ACPI / hotplug / PCI: Rework acpiphp_check_host_bridge()

Since the only existing caller of acpiphp_check_host_bridge(),
which is acpi_pci_root_scan_dependent(), already has a struct
acpi_device pointer needed to obtain the ACPIPHP context, it
doesn't make sense to execute acpi_bus_get_device() on its
handle in acpiphp_handle_to_bridge() just in order to get that
pointer back.

For this reason, modify acpiphp_check_host_bridge() to take
a struct acpi_device pointer as its argument and rearrange the
code accordingly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

show more ...

ACPI / hotplug / PCI: Hotplug notifications from acpi_bus_notify()

Since acpi_bus_notify() is executed on all notifications for all
devices anyway, make it execute acpi_device_hotplug() for all
hotp

ACPI / hotplug / PCI: Hotplug notifications from acpi_bus_notify()

Since acpi_bus_notify() is executed on all notifications for all
devices anyway, make it execute acpi_device_hotplug() for all
hotplug events instead of installing notify handlers pointing to
the same function for all hotplug devices.

This change reduces both the size and complexity of ACPI-based device
hotplug code. Moreover, since acpi_device_hotplug() only does
significant things for devices that have either an ACPI scan handler,
or a hotplug context with .eject() defined, and those devices
had notify handlers pointing to acpi_hotplug_notify_cb() installed
before anyway, this modification shouldn't change functionality.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

show more ...

ACPI / hotplug / PCI: Simplify acpi_install_hotplug_notify_handler()

Since acpi_hotplug_notify_cb() does not use its data argument any
more, the second argument of acpi_install_hotplug_notify_handle

ACPI / hotplug / PCI: Simplify acpi_install_hotplug_notify_handler()

Since acpi_hotplug_notify_cb() does not use its data argument any
more, the second argument of acpi_install_hotplug_notify_handler()
can be dropped, so do that and update its callers accordingly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

show more ...

ACPI / hotplug / PCI: Consolidate ACPIPHP with ACPI core hotplug

The ACPI-based PCI hotplug (ACPIPHP) code currently attaches its
hotplug context objects directly to ACPI namespace nodes representin

ACPI / hotplug / PCI: Consolidate ACPIPHP with ACPI core hotplug

The ACPI-based PCI hotplug (ACPIPHP) code currently attaches its
hotplug context objects directly to ACPI namespace nodes representing
hotplug devices. However, after recent changes causing struct
acpi_device to be created for every namespace node representing a
device (regardless of its status), that is not necessary any more.
Moreover, it's vulnerable to the theoretical issue that the ACPI
handle passed in the context between handle_hotplug_event() and
hotplug_event_work() may become invalid in the meantime (as a
result of a concurrent table unload).

In principle, this issue might be addressed by adding a non-empty
release handler for ACPIPHP hotplug context objects analogous to
acpi_scan_drop_device(), but that would duplicate the code in that
function and in acpi_device_del_work_fn(). For this reason, it's
better to modify ACPIPHP to attach its device hotplug contexts to
struct device objects representing hotplug devices and make it
use acpi_hotplug_notify_cb() as its notify handler. At the same
time, acpi_device_hotplug() can be modified to dispatch the new
.hp.event() callback pointing to acpiphp_hotplug_event() from ACPI
device objects associated with PCI devices or use the generic
ACPI device hotplug code for device objects with matching scan
handlers.

This allows the existing code duplication between ACPIPHP and the
ACPI core to be reduced too and makes further ACPI-based device
hotplug consolidation possible.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

show more ...

ACPI / hotplug / PCI: Define hotplug context lock in the core

Subsequent changes will require the ACPI core to acquire the lock
protecting the ACPIPHP hotplug contexts, so move the definition of
the

ACPI / hotplug / PCI: Define hotplug context lock in the core

Subsequent changes will require the ACPI core to acquire the lock
protecting the ACPIPHP hotplug contexts, so move the definition of
the lock to the core and change its name to be more generic.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

show more ...

ACPI / hotplug / PCI: Do not pass ACPI handle to hotplug_event()

Since hotplug_event() can get the ACPI handle needed for debug
printouts from its context argument, there's no need to pass the
handl

ACPI / hotplug / PCI: Do not pass ACPI handle to hotplug_event()

Since hotplug_event() can get the ACPI handle needed for debug
printouts from its context argument, there's no need to pass the
handle to it. Moreover, the second argument's type may be changed
to (struct acpiphp_context *), because that's what is always passed
to hotplug_event() as the second argument anyway.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

show more ...

ACPI / hotplug / PCI: Use acpi_handle_debug() in hotplug_event()

Make hotplug_event() use acpi_handle_debug() instead of an open-coded
debug message printing and clean up the messages printed by it.

ACPI / hotplug / PCI: Use acpi_handle_debug() in hotplug_event()

Make hotplug_event() use acpi_handle_debug() instead of an open-coded
debug message printing and clean up the messages printed by it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

show more ...

ACPI / hotplug / PCI: Simplify hotplug_event()

A few lines of code can be cut from hotplug_event() by defining
and initializing the slot variable at the top of the function,
so do that.

Signed-off-

ACPI / hotplug / PCI: Simplify hotplug_event()

A few lines of code can be cut from hotplug_event() by defining
and initializing the slot variable at the top of the function,
so do that.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

show more ...

ACPI / hotplug / PCI: Drop crit_sect locking

After recent PCI core changes related to the rescan/remove locking,
the code sections under crit_sect mutexes from ACPIPHP slot objects
are always execut

ACPI / hotplug / PCI: Drop crit_sect locking

After recent PCI core changes related to the rescan/remove locking,
the code sections under crit_sect mutexes from ACPIPHP slot objects
are always executed under the general PCI rescan/remove lock.
For this reason, the crit_sect mutexes are simply redundant, so drop
them.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

show more ...

ACPI / hotplug / PCI: Drop acpiphp_bus_add()

acpiphp_bus_add() is only called from one place, so move the code out
of it into that place and drop it. Also make that code use
func_to_acpi_device() t

ACPI / hotplug / PCI: Drop acpiphp_bus_add()

acpiphp_bus_add() is only called from one place, so move the code out
of it into that place and drop it. Also make that code use
func_to_acpi_device() to get the struct acpi_device pointer it needs
instead of calling acpi_bus_get_device() which may be costly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

show more ...

ACPI / hotplug / PCI: Store acpi_device pointer in acpiphp_context

After recent modifications of the ACPI core making it create a struct
acpi_device object for every namespace node representing a de

ACPI / hotplug / PCI: Store acpi_device pointer in acpiphp_context

After recent modifications of the ACPI core making it create a struct
acpi_device object for every namespace node representing a device
regardless of the current status of that device the ACPIPHP code
can store a struct acpi_device pointer instead of an ACPI handle
in struct acpiphp_context. This immediately makes it possible to
avoid making potentially costly calls to acpi_bus_get_device() in
two places and allows some more simplifications to be made going
forward.

The reason why that is correct is because ACPIPHP only installs
hotify handlers for namespace nodes that exist when
acpiphp_enumerate_slots() is called for their parent bridge.
That only happens if the parent bridge has an ACPI companion
associated with it, which means that the ACPI namespace scope
in question has been scanned already at that point. That, in
turn, means that struct acpi_device objects have been created
for all namespace nodes in that scope and pointers to those
objects can be stored directly instead of their ACPI handles.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

show more ...

ACPI / hotplug / PCI: Rework acpiphp_no_hotplug()

If a struct acpi_device pointer is passed to acpiphp_no_hotplug()
instead of an ACPI handle, the function won't need to call
acpi_bus_get_device(),

ACPI / hotplug / PCI: Rework acpiphp_no_hotplug()

If a struct acpi_device pointer is passed to acpiphp_no_hotplug()
instead of an ACPI handle, the function won't need to call
acpi_bus_get_device(), which may be costly, any more. Then,
trim_stale_devices() can call acpiphp_no_hotplug() passing
the struct acpi_device object it already has directly to that
function.

Make those changes and update slot_no_hotplug() accordingly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

show more ...

ACPI / hotplug / PCI: Drop acpiphp_bus_trim()

If trim_stale_devices() calls acpi_bus_trim() directly, we can
save a potentially costly acpi_bus_get_device() invocation. After
making that change acp

ACPI / hotplug / PCI: Drop acpiphp_bus_trim()

If trim_stale_devices() calls acpi_bus_trim() directly, we can
save a potentially costly acpi_bus_get_device() invocation. After
making that change acpiphp_bus_trim() would only be called from one
place, so move the code from it to that place and drop it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

show more ...

ACPI / hotplug / PCI: Simplify register_slot()

The err label in register_slot() is only jumped to from one place,
so move the code under the label to that place and drop the label.

Signed-off-by: R

ACPI / hotplug / PCI: Simplify register_slot()

The err label in register_slot() is only jumped to from one place,
so move the code under the label to that place and drop the label.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

show more ...

ACPI / hotplug / PCI: Proper kerneldoc comments for enumeration/removal

Add proper kerneldoc comments describing acpiphp_enumerate_slots()
and acpiphp_remove_slots().

Signed-off-by: Rafael J. Wysoc

ACPI / hotplug / PCI: Proper kerneldoc comments for enumeration/removal

Add proper kerneldoc comments describing acpiphp_enumerate_slots()
and acpiphp_remove_slots().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

show more ...

ACPI / hotplug / PCI: Simplify disable_slot()

After recent PCI core changes related to the rescan/remove locking,
the ACPIPHP's disable_slot() function is only called under the
general PCI rescan/re

ACPI / hotplug / PCI: Simplify disable_slot()

After recent PCI core changes related to the rescan/remove locking,
the ACPIPHP's disable_slot() function is only called under the
general PCI rescan/remove lock, so it doesn't have to use
dev_in_slot() any more to avoid race conditions. Make it simply
walk the devices on the bus and drop the ones in the slot being
disabled and drop dev_in_slot() which has no more users.

Moreover, to avoid problems described in the changelog of commit
29ed1f29b68a (PCI: pciehp: Fix null pointer deref when hot-removing
SR-IOV device), make disable_slot() carry out the list walk in
reverse order.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

show more ...

ACPI / hotplug / PCI: Fix bridge removal race vs dock events

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

ACPI / hotplug / PCI: Fix bridge removal race vs dock events

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>

show more ...

ACPI / hotplug / PCI: Fix bridge removal race in handle_hotplug_event()

If a PCI bridge with an ACPIPHP context attached is removed via
sysfs, the code path executed as a result is the following:

p

ACPI / hotplug / PCI: Fix bridge removal race in handle_hotplug_event()

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>

show more ...

ACPI / hotplug / PCI: Scan root bus under the PCI rescan-remove lock

Since acpiphp_check_bridge() called by acpiphp_check_host_bridge()
does things that require PCI rescan-remove locking around it,

ACPI / hotplug / PCI: Scan root bus under the PCI rescan-remove lock

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>

show more ...

ACPI / hotplug / PCI: Move PCI rescan-remove locking to hotplug_event()

Commit 9217a984671e (ACPI / hotplug / PCI: Use global PCI rescan-remove
locking) modified ACPIPHP to protect its PCI device re

ACPI / hotplug / PCI: Move PCI rescan-remove locking to hotplug_event()

Commit 9217a984671e (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 9217a984671e 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: 9217a984671e (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>

show more ...

ACPI / hotplug / PCI: Remove entries from bus->devices in reverse order

According to the changelog of commit 29ed1f29b68a (PCI: pciehp: Fix null
pointer deref when hot-removing SR-IOV device) it is

ACPI / hotplug / PCI: Remove entries from bus->devices in reverse order

According to the changelog of commit 29ed1f29b68a (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>

show more ...

ACPI / hotplug / PCI: Use global PCI rescan-remove locking

Multiple race conditions are possible between the ACPI-based PCI hotplug
(ACPIPHP) and the generic PCI bus rescan and device removal that c

ACPI / hotplug / PCI: Use global PCI rescan-remove locking

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>

show more ...

ACPIPHP / radeon / nouveau: Fix VGA switcheroo problem related to hotplug

The changes in the ACPI-based PCI hotplug (ACPIPHP) subsystem made
during the 3.12 development cycle uncovered a problem wit

ACPIPHP / radeon / nouveau: Fix VGA switcheroo problem related to hotplug

The changes in the ACPI-based PCI hotplug (ACPIPHP) subsystem made
during the 3.12 development cycle uncovered a problem with VGA
switcheroo that on some systems, when the device-specific method
(ATPX in the radeon case, _DSM in the nouveau case) is used to turn
off the discrete graphics, the BIOS generates ACPI hotplug events for
that device and those events cause ACPIPHP to attempt to remove the
device from the system (they are events for a device that was present
previously and is not present any more, so that's what should be done
according to the spec). Then, the system stops functioning correctly.

Since the hotplug events in question were simply silently ignored
previously, the least intrusive way to address that problem is to
make ACPIPHP ignore them again. For this purpose, introduce a new
ACPI device flag, no_hotplug, and modify ACPIPHP to ignore hotplug
events for PCI devices whose ACPI companions have that flag set.
Next, make the radeon and nouveau switcheroo detection code set the
no_hotplug flag for the discrete graphics' ACPI companion.

Fixes: bbd34fcdd1b2 (ACPI / hotplug / PCI: Register all devices under the given bridge)
References: https://bugzilla.kernel.org/show_bug.cgi?id=61891
References: https://bugzilla.kernel.org/show_bug.cgi?id=64891
Reported-and-tested-by: Mike Lothian <mike@fireburn.co.uk>
Reported-and-tested-by: <madcatx@atlas.cz>
Reported-and-tested-by: Joaquín Aramendía <samsagax@gmail.com>
Cc: Alex Deucher <alexdeucher@gmail.com>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: 3.12+ <stable@vger.kernel.org> # 3.12+

show more ...

ACPI / PCI / hotplug: Avoid warning when _ADR not present

acpiphp_enumerate_slots() walks ACPI namenamespace under
a PCI host bridge with callback register_slot().
register_slot() evaluates _ADR for

ACPI / PCI / hotplug: Avoid warning when _ADR not present

acpiphp_enumerate_slots() walks ACPI namenamespace under
a PCI host bridge with callback register_slot().
register_slot() evaluates _ADR for all the device objects
and emits a warning message for any error. Some platforms
have _HID device objects (such as HPET and IPMI), which
trigger unnecessary warning messages.

This patch avoids emitting a warning message when a target
device object does not have _ADR.

Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Cc: 3.12+ <stable@vger.kernel.org> # 3.12+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

show more ...

ACPI / scan: Add acpi_device objects for all device nodes in the namespace

Modify the ACPI namespace scanning code to register a struct
acpi_device object for every namespace node representing a dev

ACPI / scan: Add acpi_device objects for all device nodes in the namespace

Modify the ACPI namespace scanning code to register a struct
acpi_device object for every namespace node representing a device,
processor and so on, even if the device represented by that namespace
node is reported to be not present and not functional by _STA.

There are multiple reasons to do that. First of all, it avoids
quite a lot of overhead when struct acpi_device objects are
deleted every time acpi_bus_trim() is run and then added again
by a subsequent acpi_bus_scan() for the same scope, although the
namespace objects they correspond to stay in memory all the time
(which always is the case on a vast majority of systems).

Second, it will allow user space to see that there are namespace
nodes representing devices that are not present at the moment and may
be added to the system. It will also allow user space to evaluate
_SUN for those nodes to check what physical slots the "missing"
devices may be put into and it will make sense to add a sysfs
attribute for _STA evaluation after this change (that will be
useful for thermal management on some systems).

Next, it will help to consolidate the ACPI hotplug handling among
subsystems by making it possible to store hotplug-related information
in struct acpi_device objects in a standard common way.

Finally, it will help to avoid a race condition related to the
deletion of ACPI namespace nodes. Namely, namespace nodes may be
deleted as a result of a table unload triggered by _EJ0 or _DCK.
If a hotplug notification for one of those nodes is triggered
right before the deletion and it executes a hotplug callback
via acpi_hotplug_execute(), the ACPI handle passed to that
callback may be stale when the callback actually runs. One way
to work around that is to always pass struct acpi_device pointers
to hotplug callbacks after doing a get_device() on the objects in
question which eliminates the use-after-free possibility (the ACPI
handles in those objects are invalidated by acpi_scan_drop_device(),
so they will trigger ACPICA errors on attempts to use them).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

show more ...