PCI/DOE: Expose DOE features via sysfs

PCIe r6.0 added support for Data Object Exchange (DOE). When DOE is
supported, the DOE Discovery Feature must be implemented per PCIe r6.1, sec
6.30.1.1. DOE

PCI/DOE: Expose DOE features via sysfs

PCIe r6.0 added support for Data Object Exchange (DOE). When DOE is
supported, the DOE Discovery Feature must be implemented per PCIe r6.1, sec
6.30.1.1. DOE allows a requester to obtain information about the other DOE
features supported by the device.

The kernel already queries the DOE features supported and caches the
values. Expose the values in sysfs to allow user space to determine which
DOE features are supported by the PCIe device.

By exposing the information to userspace, tools like lspci can relay the
information to users. By listing all of the supported features we can allow
userspace to parse the list, which might include vendor specific features
as well as yet to be supported features.

As the DOE Discovery feature must always be supported we treat it as a
special named attribute case. This allows the usual PCI attribute_group
handling to correctly create the doe_features directory when registering
pci_doe_sysfs_group (otherwise it doesn't and sysfs_add_file_to_group()
will seg fault).

After this patch is supported you can see something like this when
attaching a DOE device:

$ ls /sys/devices/pci0000:00/0000:00:02.0//doe*
0001:01 0001:02 doe_discovery

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alistair Francis <[email protected]>
[bhelgaas: drop pci_doe_sysfs_init() stub return, make
DEVICE_ATTR_RO(doe_discovery) static]
Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Jonathan Cameron <[email protected]>

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PCI: of: Create device tree PCI host bridge node

PCI devices device tree nodes can be already created. This was introduced
by commit 407d1a51921e ("PCI: Create device tree node for bridge").

In ord

PCI: of: Create device tree PCI host bridge node

PCI devices device tree nodes can be already created. This was introduced
by commit 407d1a51921e ("PCI: Create device tree node for bridge").

In order to have device tree nodes related to PCI devices attached on their
PCI root bus (the PCI bus handled by the PCI host bridge), a PCI root bus
device tree node is needed. This root bus node will be used as the parent
node of the first level devices scanned on the bus. On device tree based
systems, this PCI root bus device tree node is set to the node of the
related PCI host bridge. The PCI host bridge node is available in the
device tree used to describe the hardware passed at boot.

On non device tree based system (such as ACPI), a device tree node for the
PCI host bridge or for the root bus does not exist. Indeed, the PCI host
bridge is not described in a device tree used at boot simply because no
device tree is passed at boot.

The device tree PCI host bridge node creation needs to be done at runtime.
This is done in the same way as for the creation of the PCI device nodes.
I.e. node and properties are created based on computed information done by
the PCI core. Also, as is done on device tree based systems, this PCI host
bridge node is used for the PCI root bus.

With this done, hardware available in a PCI device that doesn't follow the
PCI model consisting in one PCI function handled by one driver can be
described by a device tree overlay loaded by the PCI device driver on non
device tree based systems. Those PCI devices provide a single PCI function
that includes several functionalities that require different drivers. The
device tree overlay describes the internal devices and their relationships.
It allows to load drivers needed by those different devices in order to
have functionalities handled.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Herve Codina <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Rob Herring (Arm) <[email protected]>

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PCI/pwrctrl: Move pci_pwrctrl_unregister() to pci_destroy_dev()

The PCI core will try to access the devices even after pci_stop_dev()
for things like Data Object Exchange (DOE), ASPM, etc.

So, move

PCI/pwrctrl: Move pci_pwrctrl_unregister() to pci_destroy_dev()

The PCI core will try to access the devices even after pci_stop_dev()
for things like Data Object Exchange (DOE), ASPM, etc.

So, move pci_pwrctrl_unregister() to the near end of pci_destroy_dev()
to make sure that the devices are powered down only after the PCI core
is done with them.

Suggested-by: Lukas Wunner <[email protected]>
Reviewed-by: Lukas Wunner <[email protected]>
Tested-by: Bartosz Golaszewski <[email protected]>
Signed-off-by: Manivannan Sadhasivam <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <[email protected]>

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PCI/pwrctrl: Unregister platform device only if one actually exists

If a PCI device has an associated device_node with power supplies,
pci_bus_add_device() creates platform devices for use by pwrctr

PCI/pwrctrl: Unregister platform device only if one actually exists

If a PCI device has an associated device_node with power supplies,
pci_bus_add_device() creates platform devices for use by pwrctrl. When the
PCI device is removed, pci_stop_dev() uses of_find_device_by_node() to
locate the related platform device, then unregisters it.

But when we remove a PCI device with no associated device node,
dev_of_node(dev) is NULL, and of_find_device_by_node(NULL) returns the
first device with "dev->of_node == NULL". The result is that we (a)
mistakenly unregister a completely unrelated platform device, leading to
issues like the first trace below, and (b) dereference the NULL pointer
from dev_of_node() when clearing OF_POPULATED, as in the second trace.

Unregister a platform device only if there is one associated with this PCI
device. This resolves issues seen when doing:

# echo 1 > /sys/bus/pci/devices/.../remove

Sample issue from unregistering the wrong platform device:

WARNING: CPU: 0 PID: 5095 at drivers/regulator/core.c:5885 regulator_unregister+0x140/0x160
Call trace:
regulator_unregister+0x140/0x160
devm_rdev_release+0x1c/0x30
release_nodes+0x68/0x100
devres_release_all+0x98/0xf8
device_unbind_cleanup+0x20/0x70
device_release_driver_internal+0x1f4/0x240
device_release_driver+0x20/0x40
bus_remove_device+0xd8/0x170
device_del+0x154/0x380
device_unregister+0x28/0x88
of_device_unregister+0x1c/0x30
pci_stop_bus_device+0x154/0x1b0
pci_stop_and_remove_bus_device_locked+0x28/0x48
remove_store+0xa0/0xb8
dev_attr_store+0x20/0x40
sysfs_kf_write+0x4c/0x68

Later NULL pointer dereference for of_node_clear_flag(NULL, OF_POPULATED):

Unable to handle kernel NULL pointer dereference at virtual address 00000000000000c0
Call trace:
pci_stop_bus_device+0x190/0x1b0
pci_stop_and_remove_bus_device_locked+0x28/0x48
remove_store+0xa0/0xb8
dev_attr_store+0x20/0x40
sysfs_kf_write+0x4c/0x68

Link: https://lore.kernel.org/r/[email protected]
Fixes: 681725afb6b9 ("PCI/pwrctl: Remove pwrctl device without iterating over all children of pwrctl parent")
Reported-by: Saurabh Sengar <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Signed-off-by: Brian Norris <[email protected]>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <[email protected]>

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PCI/pwrctrl: Rename pwrctrl functions and structures

Rename pwrctrl functions and structures from "pwrctl" to "pwrctrl" to match
the similar file renames.

Link: https://lore.kernel.org/r/2024111521

PCI/pwrctrl: Rename pwrctrl functions and structures

Rename pwrctrl functions and structures from "pwrctl" to "pwrctrl" to match
the similar file renames.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Bjorn Helgaas <[email protected]>
Signed-off-by: Krzysztof Wilczyński <[email protected]>
Acked-by: Krzysztof Wilczyński <[email protected]>

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PCI/pwrctl: Remove pwrctl device without iterating over all children of pwrctl parent

There is no need to iterate over all children of the pwrctl device parent
to remove the pwrctl device. Since the

PCI/pwrctl: Remove pwrctl device without iterating over all children of pwrctl parent

There is no need to iterate over all children of the pwrctl device parent
to remove the pwrctl device. Since the pwrctl device associated with the
PCI device can be found using of_find_device_by_node() API, use it directly
instead.

Any pwrctl devices lying around without getting associated with the PCI
devices will be removed once their parent device gets removed.

Link: https://lore.kernel.org/r/[email protected]
Tested-by: Bartosz Golaszewski <[email protected]>
Tested-by: Krishna chaitanya chundru <[email protected]>
Signed-off-by: Manivannan Sadhasivam <[email protected]>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <[email protected]>
Signed-off-by: Krzysztof Wilczyński <[email protected]>
Reviewed-by: Bartosz Golaszewski <[email protected]>

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PCI: Make pci_destroy_dev() concurrent safe

Use an atomic flag instead of the racy check against the device's kobj
parent. We shouldn't be poking into device implementation details at this
level any

PCI: Make pci_destroy_dev() concurrent safe

Use an atomic flag instead of the racy check against the device's kobj
parent. We shouldn't be poking into device implementation details at this
level anyway.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Keith Busch <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Jonathan Cameron <[email protected]>

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PCI: Make pci_stop_dev() concurrent safe

Use the atomic ADDED flag to ensure concurrent callers can't attempt to
stop the device multiple times. Callers should currently all be holding the
pci_resca

PCI: Make pci_stop_dev() concurrent safe

Use the atomic ADDED flag to ensure concurrent callers can't attempt to
stop the device multiple times. Callers should currently all be holding the
pci_rescan_remove_lock, so there shouldn't be an existing race. But that
global lock can cause lock dependency issues, so this is preparing to
reduce reliance on that lock by using the existing existing atomic bit ops.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Keith Busch <[email protected]>
[bhelgaas: squash https://lore.kernel.org/r/[email protected]]
Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Jonathan Cameron <[email protected]>

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PCI: Pass domain number to pci_bus_release_domain_nr() explicitly

The pci_bus_release_domain_nr() API is supposed to free the domain
number allocated by pci_bus_find_domain_nr(). Most of the callers

PCI: Pass domain number to pci_bus_release_domain_nr() explicitly

The pci_bus_release_domain_nr() API is supposed to free the domain
number allocated by pci_bus_find_domain_nr(). Most of the callers of
pci_bus_find_domain_nr(), store the domain number in pci_bus::domain_nr.

As such, the pci_bus_release_domain_nr() implicitly frees the domain
number by dereferencing 'struct pci_bus'. However, one of the callers
of this API, the PCI endpoint subsystem, doesn't have 'struct pci_bus',
so it only passes NULL. Due to this, the API will end up dereferencing
the NULL pointer.

To fix this issue, pass the domain number to this API explicitly. Since
'struct pci_bus' is not used for anything else other than extracting the
domain number, it makes sense to pass the domain number directly.

Fixes: 0328947c5032 ("PCI: endpoint: Assign PCI domain number for endpoint controllers")
Closes: https://lore.kernel.org/linux-pci/[email protected]
Link: https://lore.kernel.org/linux-pci/[email protected]
Reported-by: Dan Carpenter <[email protected]>
Signed-off-by: Manivannan Sadhasivam <[email protected]>
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <[email protected]>

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PCI/NPEM: Add Native PCIe Enclosure Management support

Native PCIe Enclosure Management (NPEM, PCIe r6.1 sec 6.28) allows managing
LEDs in storage enclosures. NPEM is indication oriented and it does

PCI/NPEM: Add Native PCIe Enclosure Management support

Native PCIe Enclosure Management (NPEM, PCIe r6.1 sec 6.28) allows managing
LEDs in storage enclosures. NPEM is indication oriented and it does not
give direct access to LEDs. Although each indication *could* represent an
individual LED, multiple indications could also be represented as a single,
multi-color LED or a single LED blinking in a specific interval. The
specification leaves that open.

Each enabled indication (capability register bit on) is represented as a
ledclass_dev which can be controlled through sysfs. For every ledclass
device only 2 brightness states are allowed: LED_ON (1) or LED_OFF (0).
This corresponds to the NPEM control register (Indication bit on/off).

Ledclass devices appear in sysfs as child devices (subdirectory) of PCI
device which has an NPEM Extended Capability and indication is enabled in
NPEM capability register. For example, these are LEDs created for pcieport
"10000:02:05.0" on my setup:

leds/
├── 10000:02:05.0:enclosure:fail
├── 10000:02:05.0:enclosure:locate
├── 10000:02:05.0:enclosure:ok
└── 10000:02:05.0:enclosure:rebuild

They can be also found in "/sys/class/leds" directory. The parent PCIe
device domain/bus/device/function address is used to guarantee uniqueness
across leds subsystem.

To enable/disable a "fail" indication, the "brightness" file can be edited:

echo 1 > ./leds/10000:02:05.0:enclosure:fail/brightness
echo 0 > ./leds/10000:02:05.0:enclosure:fail/brightness

PCIe r6.1, sec 7.9.19.2 defines the possible indications.

Multiple indications for same parent PCIe device can conflict and hardware
may update them when processing new request. To avoid issues, driver
refresh all indications by reading back control register.

This driver expects to be the exclusive NPEM extended capability manager.
It waits up to 1 second after imposing new request, it doesn't verify if
controller is busy before write, and it assumes the mutex lock gives
protection from concurrent updates.

If _DSM LED management is available, we assume the platform may be using
NPEM for its own purposes (see PCI Firmware Spec r3.3 sec 4.7), so the
driver does not use NPEM. A future patch will add _DSM support; an info
message notes whether NPEM or _DSM is being used.

NPEM is a PCIe extended capability so it should be registered in
pcie_init_capabilities() but it is not possible due to LED dependency. The
parent pci_device must be added earlier for led_classdev_register() to be
successful. NPEM does not require configuration on kernel side, so it is
safe to register LED devices later.

Link: https://lore.kernel.org/r/[email protected]
Suggested-by: Lukas Wunner <[email protected]>
Signed-off-by: Mariusz Tkaczyk <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Tested-by: Stuart Hayes <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Ilpo Järvinen <[email protected]>

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PCI: Don't rely on of_platform_depopulate() for reused OF-nodes

of_platform_depopulate() doesn't play nicely with reused OF nodes - it
ignores the ones that are not marked explicitly as populated an

PCI: Don't rely on of_platform_depopulate() for reused OF-nodes

of_platform_depopulate() doesn't play nicely with reused OF nodes - it
ignores the ones that are not marked explicitly as populated and it may
happen that the PCI device goes away before the platform device in which
case the PCI core clears the OF_POPULATED bit.

Unconditionally unregister the platform devices for child nodes when
stopping the PCI device.

Link: https://lore.kernel.org/r/[email protected]
Fixes: 8fb18619d910 ("PCI/pwrctl: Create platform devices for child OF nodes of the port node")
Signed-off-by: Bartosz Golaszewski <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Acked-by: Manivannan Sadhasivam <[email protected]>

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PCI/pwrctl: Create platform devices for child OF nodes of the port node

In preparation for introducing PCI device power control - a set of
library functions that will allow powering-up of PCI device

PCI/pwrctl: Create platform devices for child OF nodes of the port node

In preparation for introducing PCI device power control - a set of
library functions that will allow powering-up of PCI devices before
they're detected on the PCI bus - we need to populate the devices
defined on the device-tree.

We are reusing the platform bus as it provides us with all the
infrastructure we need to match the pwrctl drivers against the
compatibles from OF nodes.

These platform devices will be probed by the driver core and bound to
the PCI pwrctl drivers we'll introduce later.

Tested-by: Amit Pundir <[email protected]>
Tested-by: Neil Armstrong <[email protected]> # on SM8550-QRD, SM8650-QRD & SM8650-HDK
Tested-by: Caleb Connolly <[email protected]> # OnePlus 8T
Acked-by: Bjorn Helgaas <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Bartosz Golaszewski <[email protected]>

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PCI: Create device tree node for bridge

The PCI endpoint device such as Xilinx Alveo PCI card maps the register
spaces from multiple hardware peripherals to its PCI BAR. Normally,
the PCI core disco

PCI: Create device tree node for bridge

The PCI endpoint device such as Xilinx Alveo PCI card maps the register
spaces from multiple hardware peripherals to its PCI BAR. Normally,
the PCI core discovers devices and BARs using the PCI enumeration process.
There is no infrastructure to discover the hardware peripherals that are
present in a PCI device, and which can be accessed through the PCI BARs.

Apparently, the device tree framework requires a device tree node for the
PCI device. Thus, it can generate the device tree nodes for hardware
peripherals underneath. Because PCI is self discoverable bus, there might
not be a device tree node created for PCI devices. Furthermore, if the PCI
device is hot pluggable, when it is plugged in, the device tree nodes for
its parent bridges are required. Add support to generate device tree node
for PCI bridges.

Add an of_pci_make_dev_node() interface that can be used to create device
tree node for PCI devices.

Add a PCI_DYNAMIC_OF_NODES config option. When the option is turned on,
the kernel will generate device tree nodes for PCI bridges unconditionally.

Initially, add the basic properties for the dynamically generated device
tree nodes which include #address-cells, #size-cells, device_type,
compatible, ranges, reg.

Acked-by: Bjorn Helgaas <[email protected]>
Signed-off-by: Lizhi Hou <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Rob Herring <[email protected]>

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PCI/DOE: Create mailboxes on device enumeration

Currently a DOE instance cannot be shared by multiple drivers because
each driver creates its own pci_doe_mb struct for a given DOE instance.
For the

PCI/DOE: Create mailboxes on device enumeration

Currently a DOE instance cannot be shared by multiple drivers because
each driver creates its own pci_doe_mb struct for a given DOE instance.
For the same reason a DOE instance cannot be shared between the PCI core
and a driver.

Moreover, finding out which protocols a DOE instance supports requires
creating a pci_doe_mb for it. If a device has multiple DOE instances,
a driver looking for a specific protocol may need to create a pci_doe_mb
for each of the device's DOE instances and then destroy those which
do not support the desired protocol. That's obviously an inefficient
way to do things.

Overcome these issues by creating mailboxes in the PCI core on device
enumeration.

Provide a pci_find_doe_mailbox() API call to allow drivers to get a
pci_doe_mb for a given (pci_dev, vendor, protocol) triple. This API is
modeled after pci_find_capability() and can later be amended with a
pci_find_next_doe_mailbox() call to iterate over all mailboxes of a
given pci_dev which support a specific protocol.

On removal, destroy the mailboxes in pci_destroy_dev(), after the driver
is unbound. This allows drivers to use DOE in their ->remove() hook.

On surprise removal, cancel ongoing DOE exchanges and prevent new ones
from being scheduled. Thereby ensure that a hot-removed device doesn't
needlessly wait for a running exchange to time out.

Tested-by: Ira Weiny <[email protected]>
Signed-off-by: Lukas Wunner <[email protected]>
Reviewed-by: Ming Li <[email protected]>
Reviewed-by: Ira Weiny <[email protected]>
Reviewed-by: Jonathan Cameron <[email protected]>
Acked-by: Bjorn Helgaas <[email protected]>
Link: https://lore.kernel.org/r/40a6f973f72ef283d79dd55e7e6fddc7481199af.1678543498.git.lukas@wunner.de
Signed-off-by: Dan Williams <[email protected]>

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PCI: Fix use-after-free in pci_bus_release_domain_nr()

Commit c14f7ccc9f5d ("PCI: Assign PCI domain IDs by ida_alloc()")
introduced a use-after-free bug in the bus removal cleanup. The issue was
fou

PCI: Fix use-after-free in pci_bus_release_domain_nr()

Commit c14f7ccc9f5d ("PCI: Assign PCI domain IDs by ida_alloc()")
introduced a use-after-free bug in the bus removal cleanup. The issue was
found with kfence:

[ 19.293351] BUG: KFENCE: use-after-free read in pci_bus_release_domain_nr+0x10/0x70

[ 19.302817] Use-after-free read at 0x000000007f3b80eb (in kfence-#115):
[ 19.309677] pci_bus_release_domain_nr+0x10/0x70
[ 19.309691] dw_pcie_host_deinit+0x28/0x78
[ 19.309702] tegra_pcie_deinit_controller+0x1c/0x38 [pcie_tegra194]
[ 19.309734] tegra_pcie_dw_probe+0x648/0xb28 [pcie_tegra194]
[ 19.309752] platform_probe+0x90/0xd8
...

[ 19.311457] kfence-#115: 0x00000000063a155a-0x00000000ba698da8, size=1072, cache=kmalloc-2k

[ 19.311469] allocated by task 96 on cpu 10 at 19.279323s:
[ 19.311562] __kmem_cache_alloc_node+0x260/0x278
[ 19.311571] kmalloc_trace+0x24/0x30
[ 19.311580] pci_alloc_bus+0x24/0xa0
[ 19.311590] pci_register_host_bridge+0x48/0x4b8
[ 19.311601] pci_scan_root_bus_bridge+0xc0/0xe8
[ 19.311613] pci_host_probe+0x18/0xc0
[ 19.311623] dw_pcie_host_init+0x2c0/0x568
[ 19.311630] tegra_pcie_dw_probe+0x610/0xb28 [pcie_tegra194]
[ 19.311647] platform_probe+0x90/0xd8
...

[ 19.311782] freed by task 96 on cpu 10 at 19.285833s:
[ 19.311799] release_pcibus_dev+0x30/0x40
[ 19.311808] device_release+0x30/0x90
[ 19.311814] kobject_put+0xa8/0x120
[ 19.311832] device_unregister+0x20/0x30
[ 19.311839] pci_remove_bus+0x78/0x88
[ 19.311850] pci_remove_root_bus+0x5c/0x98
[ 19.311860] dw_pcie_host_deinit+0x28/0x78
[ 19.311866] tegra_pcie_deinit_controller+0x1c/0x38 [pcie_tegra194]
[ 19.311883] tegra_pcie_dw_probe+0x648/0xb28 [pcie_tegra194]
[ 19.311900] platform_probe+0x90/0xd8
...

[ 19.313579] CPU: 10 PID: 96 Comm: kworker/u24:2 Not tainted 6.2.0 #4
[ 19.320171] Hardware name: /, BIOS 1.0-d7fb19b 08/10/2022
[ 19.325852] Workqueue: events_unbound deferred_probe_work_func

The stack trace is a bit misleading as dw_pcie_host_deinit() doesn't
directly call pci_bus_release_domain_nr(). The issue turns out to be in
pci_remove_root_bus() which first calls pci_remove_bus() which frees the
struct pci_bus when its struct device is released. Then
pci_bus_release_domain_nr() is called and accesses the freed struct
pci_bus. Reordering these fixes the issue.

Fixes: c14f7ccc9f5d ("PCI: Assign PCI domain IDs by ida_alloc()")
Link: https://lore.kernel.org/r/[email protected]
Link: https://lore.kernel.org/r/[email protected]
Reported-by: Jon Hunter <[email protected]>
Tested-by: Jon Hunter <[email protected]>
Signed-off-by: Rob Herring <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Kuppuswamy Sathyanarayanan <[email protected]>
Cc: [email protected] # v6.2+
Cc: Pali Rohár <[email protected]>

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PCI: Introduce pci_dev_for_each_resource()

Instead of open-coding it everywhere introduce a tiny helper that can be
used to iterate over each resource of a PCI device, and convert the most
obvious u

PCI: Introduce pci_dev_for_each_resource()

Instead of open-coding it everywhere introduce a tiny helper that can be
used to iterate over each resource of a PCI device, and convert the most
obvious users into it.

While at it drop doubled empty line before pdev_sort_resources().

No functional changes intended.

Suggested-by: Andy Shevchenko <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mika Westerberg <[email protected]>
Signed-off-by: Andy Shevchenko <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Krzysztof Wilczyński <[email protected]>

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PCI: Assign PCI domain IDs by ida_alloc()

Replace assignment of PCI domain IDs from atomic_inc_return() to
ida_alloc().

Use two IDAs, one for static domain allocations (those which are defined in
d

PCI: Assign PCI domain IDs by ida_alloc()

Replace assignment of PCI domain IDs from atomic_inc_return() to
ida_alloc().

Use two IDAs, one for static domain allocations (those which are defined in
device tree) and second for dynamic allocations (all other).

During removal of root bus / host bridge, also release the domain ID. The
released ID can be reused again, for example when dynamically loading and
unloading native PCI host bridge drivers.

This change also allows to mix static device tree assignment and dynamic by
kernel as all static allocations are reserved in dynamic pool.

[bhelgaas: set "err" if "bus->domain_nr < 0"]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Pali Rohár <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>

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PCI: Remove reset_fn field from pci_dev

"reset_fn" indicates whether the device supports any reset mechanism.
Remove the use of reset_fn in favor of the reset_methods array that tracks
supported res

PCI: Remove reset_fn field from pci_dev

"reset_fn" indicates whether the device supports any reset mechanism.
Remove the use of reset_fn in favor of the reset_methods array that tracks
supported reset mechanisms of a device and their ordering.

The octeon driver incorrectly used reset_fn to detect whether the device
supports FLR or not. Use pcie_reset_flr() to probe whether it supports FLR.

Co-developed-by: Alex Williamson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alex Williamson <[email protected]>
Signed-off-by: Amey Narkhede <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Alex Williamson <[email protected]>
Reviewed-by: Raphael Norwitz <[email protected]>

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PCI/sysfs: Convert "reset" to static attribute

The "reset" sysfs attribute allows for resetting a PCI function.
Previously it was dynamically created either by pci_bus_add_device() or
the pci_sysfs_

PCI/sysfs: Convert "reset" to static attribute

The "reset" sysfs attribute allows for resetting a PCI function.
Previously it was dynamically created either by pci_bus_add_device() or
the pci_sysfs_init() initcall, but since it doesn't need to be created or
removed dynamically, we can use a static attribute so the device model
takes care of addition and removal automatically.

Convert "reset" to a static attribute and use the .is_visible() callback to
check whether the device supports reset.

Clear reset_fn in pci_stop_dev() instead of pci_remove_capabilities_sysfs()
since we no longer explicitly remove the "reset" sysfs file.

[bhelgaas: commit log]
Suggested-by: Oliver O'Halloran <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Krzysztof Wilczyński <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>

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PCI: Fix pci_host_bridge struct device release/free handling

The PCI code has several paths where the struct pci_host_bridge is freed
directly. This is wrong because it contains a struct device whic

PCI: Fix pci_host_bridge struct device release/free handling

The PCI code has several paths where the struct pci_host_bridge is freed
directly. This is wrong because it contains a struct device which is
refcounted and should be freed using put_device(). This can result in
use-after-free errors. I think this problem has existed since 2012 with
commit 7b5436635800 ("PCI: add generic device into pci_host_bridge
struct"). It generally hasn't mattered as most host bridge drivers are
still built-in and can't unbind.

The problem is a struct device should never be freed directly once
device_initialize() is called and a ref is held, but that doesn't happen
until pci_register_host_bridge(). There's then a window between allocating
the host bridge and pci_register_host_bridge() where kfree should be used.
This is fragile and requires callers to do the right thing. To fix this, we
need to split device_register() into device_initialize() and device_add()
calls, so that the host bridge struct is always freed by using a
put_device().

devm_pci_alloc_host_bridge() is using devm_kzalloc() to allocate struct
pci_host_bridge which will be freed directly. Instead, we can use a custom
devres action to call put_device().

Link: https://lore.kernel.org/r/[email protected]
Reported-by: Anders Roxell <[email protected]>
Tested-by: Anders Roxell <[email protected]>
Signed-off-by: Rob Herring <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Lorenzo Pieralisi <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>

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PCI/ASPM: Fix link_state teardown on device removal

Upon removal of the last device on a bus, the link_state of the bridge
leading to that bus is sought to be torn down by having pci_stop_dev()
call

PCI/ASPM: Fix link_state teardown on device removal

Upon removal of the last device on a bus, the link_state of the bridge
leading to that bus is sought to be torn down by having pci_stop_dev()
call pcie_aspm_exit_link_state().

When ASPM was originally introduced by commit 7d715a6c1ae5 ("PCI: add
PCI Express ASPM support"), it determined whether the device being
removed is the last one by calling list_empty() on the bridge's
subordinate devices list. That didn't work because the device is only
removed from the list slightly later in pci_destroy_dev().

Commit 3419c75e15f8 ("PCI: properly clean up ASPM link state on device
remove") attempted to fix it by calling list_is_last(), but that's not
correct either because it checks whether the device is at the *end* of
the list, not whether it's the last one *left* in the list. If the user
removes the device which happens to be at the end of the list via sysfs
but other devices are preceding the device in the list, the link_state
is torn down prematurely.

The real fix is to move the invocation of pcie_aspm_exit_link_state() to
pci_destroy_dev() and reinstate the call to list_empty(). Remove a
duplicate check for dev->bus->self because pcie_aspm_exit_link_state()
already contains an identical check.

Fixes: 7d715a6c1ae5 ("PCI: add PCI Express ASPM support")
Signed-off-by: Lukas Wunner <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Cc: Shaohua Li <[email protected]>
Cc: [email protected] # v2.6.26

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PCI: Remove unnecessary include of <linux/pci-aspm.h>

Several PCI core files include pci-aspm.h even though they don't need
anything provided by that file. Remove the unnecessary includes of it.

S

PCI: Remove unnecessary include of <linux/pci-aspm.h>

Several PCI core files include pci-aspm.h even though they don't need
anything provided by that file. Remove the unnecessary includes of it.

Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Sinan Kaya <[email protected]>

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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

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 <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Lukas Wunner <[email protected]>
Acked-by: Michael Ellerman <[email protected]>

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PCI: Add SPDX GPL-2.0 when no license was specified

b24413180f56 ("License cleanup: add SPDX GPL-2.0 license identifier to
files with no license") added SPDX GPL-2.0 to several PCI files that
previo

PCI: Add SPDX GPL-2.0 when no license was specified

b24413180f56 ("License cleanup: add SPDX GPL-2.0 license identifier to
files with no license") added SPDX GPL-2.0 to several PCI files that
previously contained no license information.

Add SPDX GPL-2.0 to all other PCI files that did not contain any license
information and hence were under the default GPL version 2 license of the
kernel.

Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>

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PCI: Detach driver before procfs & sysfs teardown on device remove

When removing a device, for example a VF being removed due to SR-IOV
teardown, a "soft" hot-unplug via 'echo 1 > remove' in sysfs,

PCI: Detach driver before procfs & sysfs teardown on device remove

When removing a device, for example a VF being removed due to SR-IOV
teardown, a "soft" hot-unplug via 'echo 1 > remove' in sysfs, or an actual
hot-unplug, we first remove the procfs and sysfs attributes for the device
before attempting to release the device from any driver bound to it.
Unbinding the driver from the device can take time. The device might need
to write out data or it might be actively in use. If it's in use by
userspace through a vfio driver, the unbind might block until the user
releases the device. This leads to a potentially non-trivial amount of
time where the device exists, but we've torn down the interfaces that
userspace uses to examine devices, for instance lspci might generate this
sort of error:

pcilib: Cannot open /sys/bus/pci/devices/0000:01:0a.3/config
lspci: Unable to read the standard configuration space header of device 0000:01:0a.3

We don't seem to have any dependence on this teardown ordering in the
kernel, so let's unbind the driver first, which is also more symmetric with
the instantiation of the device in pci_bus_add_device().

Signed-off-by: Alex Williamson <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>

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