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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 <bhelgaas@google.com>
Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
Link: https://lore.kernel.org/r/1692120000-46900-3-git-send-email-lizhi.hou@amd.com
Signed-off-by: Rob Herring <robh@kernel.org>
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Pull compute express link updates from Dan Williams:
"DOE support is promoted from drivers/cxl/ to drivers/pci/ with Bjorn's
blessing, and the CXL core continues to mature its media management
capabilities with support for listing and injecting media errors. Some
late fixes that missed v6.3-final are also included:
- Refactor the DOE infrastructure (Data Object Exchange
PCI-config-cycle mailbox) to be a facility of the PCI core rather
than the CXL core.
This is foundational for upcoming support for PCI
device-attestation and PCIe / CXL link encryption.
- Add support for retrieving and injecting poison for CXL memory
expanders.
This enabling uses trace-events to convey CXL media error records
to user tooling. It includes translation of device-local addresses
(DPA) to system physical addresses (SPA) and their corresponding
CXL region.
- Fixes for decoder enumeration that missed v6.3-final
- Miscellaneous fixups"
* tag 'cxl-for-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl: (38 commits)
cxl/test: Add mock test for set_timestamp
cxl/mbox: Update CMD_RC_TABLE
tools/testing/cxl: Require CONFIG_DEBUG_FS
tools/testing/cxl: Add a sysfs attr to test poison inject limits
tools/testing/cxl: Use injected poison for get poison list
tools/testing/cxl: Mock the Clear Poison mailbox command
tools/testing/cxl: Mock the Inject Poison mailbox command
cxl/mem: Add debugfs attributes for poison inject and clear
cxl/memdev: Trace inject and clear poison as cxl_poison events
cxl/memdev: Warn of poison inject or clear to a mapped region
cxl/memdev: Add support for the Clear Poison mailbox command
cxl/memdev: Add support for the Inject Poison mailbox command
tools/testing/cxl: Mock support for Get Poison List
cxl/trace: Add an HPA to cxl_poison trace events
cxl/region: Provide region info to the cxl_poison trace event
cxl/memdev: Add trigger_poison_list sysfs attribute
cxl/trace: Add TRACE support for CXL media-error records
cxl/mbox: Add GET_POISON_LIST mailbox command
cxl/mbox: Initialize the poison state
cxl/mbox: Restrict poison cmds to debugfs cxl_raw_allow_all
...
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git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci
Pull pci updates from Bjorn Helgaas:
"Resource management:
- Add pci_dev_for_each_resource() and pci_bus_for_each_resource()
iterators
PCIe native device hotplug:
- Fix AB-BA deadlock between reset_lock and device_lock
Power management:
- Wait longer for devices to become ready after resume (as we do for
reset) to accommodate Intel Titan Ridge xHCI devices
- Extend D3hot delay for NVIDIA HDA controllers to avoid
unrecoverable devices after a bus reset
Error handling:
- Clear PCIe Device Status after EDR since generic error recovery now
only clears it when AER is native
ASPM:
- Work around Chromebook firmware defect that clobbers Capability
list (including ASPM L1 PM Substates Cap) when returning from
D3cold to D0
Freescale i.MX6 PCIe controller driver:
- Install imprecise external abort handler only when DT indicates
PCIe support
Freescale Layerscape PCIe controller driver:
- Add ls1028a endpoint mode support
Qualcomm PCIe controller driver:
- Add SM8550 DT binding and driver support
- Add SDX55 DT binding and driver support
- Use bulk APIs for clocks of IP 1.0.0, 2.3.2, 2.3.3
- Use bulk APIs for reset of IP 2.1.0, 2.3.3, 2.4.0
- Add DT "mhi" register region for supported SoCs
- Expose link transition counts via debugfs to help debug low power
issues
- Support system suspend and resume; reduce interconnect bandwidth
and turn off clock and PHY if there are no active devices
- Enable async probe by default to reduce boot time
Miscellaneous:
- Sort controller Kconfig entries by vendor"
* tag 'pci-v6.4-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci: (56 commits)
PCI: xilinx: Drop obsolete dependency on COMPILE_TEST
PCI: mobiveil: Sort Kconfig entries by vendor
PCI: dwc: Sort Kconfig entries by vendor
PCI: Sort controller Kconfig entries by vendor
PCI: Use consistent controller Kconfig menu entry language
PCI: xilinx-nwl: Add 'Xilinx' to Kconfig prompt
PCI: hv: Add 'Microsoft' to Kconfig prompt
PCI: meson: Add 'Amlogic' to Kconfig prompt
PCI: Use of_property_present() for testing DT property presence
PCI/PM: Extend D3hot delay for NVIDIA HDA controllers
dt-bindings: PCI: qcom: Document msi-map and msi-map-mask properties
PCI: qcom: Add SM8550 PCIe support
dt-bindings: PCI: qcom: Add SM8550 compatible
PCI: qcom: Add support for SDX55 SoC
dt-bindings: PCI: qcom-ep: Fix the unit address used in example
dt-bindings: PCI: qcom: Add SDX55 SoC
dt-bindings: PCI: qcom: Update maintainers entry
PCI: qcom: Enable async probe by default
PCI: qcom: Add support for system suspend and resume
PCI/PM: Drop pci_bridge_wait_for_secondary_bus() timeout parameter
...
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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 <ira.weiny@intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Ming Li <ming4.li@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/40a6f973f72ef283d79dd55e7e6fddc7481199af.1678543498.git.lukas@wunner.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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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/20230329123835.2724518-1-robh@kernel.org
Link: https://lore.kernel.org/r/b529cb69-0602-9eed-fc02-2f068707a006@nvidia.com
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Cc: stable@vger.kernel.org # v6.2+
Cc: Pali Rohár <pali@kernel.org>
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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 <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230330162434.35055-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Krzysztof Wilczyński <kw@linux.com>
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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/20220714184130.5436-1-pali@kernel.org
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
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"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 <alex.williamson@redhat.com>
Link: https://lore.kernel.org/r/20210817180500.1253-5-ameynarkhede03@gmail.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
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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 <oohall@gmail.com>
Link: https://lore.kernel.org/r/20210416205856.3234481-4-kw@linux.com
Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
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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/20200513223859.11295-2-robh@kernel.org
Reported-by: Anders Roxell <anders.roxell@linaro.org>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
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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 <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Shaohua Li <shaohua.li@intel.com>
Cc: stable@vger.kernel.org # v2.6.26
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- Use sysfs_match_string() to simplify ASPM sysfs parsing (Andy
Shevchenko)
- Remove unnecessary includes of <linux/pci-aspm.h> (Bjorn Helgaas)
* pci/aspm:
PCI: Remove unnecessary include of <linux/pci-aspm.h>
iwlwifi: Remove unnecessary include of <linux/pci-aspm.h>
ath9k: Remove unnecessary include of <linux/pci-aspm.h>
igb: Remove unnecessary include of <linux/pci-aspm.h>
PCI/ASPM: Convert to use sysfs_match_string() helper
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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 <bhelgaas@google.com>
Reviewed-by: Sinan Kaya <okaya@kernel.org>
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When a PCI device is detected, pdev->is_added is set to 1 and proc and
sysfs entries are created.
When the device is removed, pdev->is_added is checked for one and then
device is detached with clearing of proc and sys entries and at end,
pdev->is_added is set to 0.
is_added and is_busmaster are bit fields in pci_dev structure sharing same
memory location.
A strange issue was observed with multiple removal and rescan of a PCIe
NVMe device using sysfs commands where is_added flag was observed as zero
instead of one while removing device and proc,sys entries are not cleared.
This causes issue in later device addition with warning message
"proc_dir_entry" already registered.
Debugging revealed a race condition between the PCI core setting the
is_added bit in pci_bus_add_device() and the NVMe driver reset work-queue
setting the is_busmaster bit in pci_set_master(). As these fields are not
handled atomically, that clears the is_added bit.
Move the is_added bit to a separate private flag variable and use atomic
functions to set and retrieve the device addition state. This avoids the
race because is_added no longer shares a memory location with is_busmaster.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=200283
Signed-off-by: Hari Vyas <hari.vyas@broadcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
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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 <bhelgaas@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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 <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
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The algorithm to update the flag indicating whether a bridge may go to D3
makes a few optimizations based on whether the update was caused by the
removal of a device on the one hand, versus the addition of a device or the
change of its D3cold flags on the other hand.
The information whether the update pertains to a removal is currently
passed in by the caller, but the function may as well determine that itself
by examining the device in question, thereby allowing for a considerable
simplification and reduction of the code.
Out of several options to determine removal, I've chosen the function
device_is_registered() because it's cheap: It merely returns the
dev->kobj.state_in_sysfs flag. That flag is set through device_add() when
the root bus is scanned and cleared through device_remove(). The call to
pci_bridge_d3_update() happens after each of these calls, respectively, so
the ordering is correct.
No functional change intended.
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Starting with v4.8, we allow a PCIe port to runtime suspend to D3hot if the
port itself and its children satisfy a number of conditions. Once a child
is removed, we recheck those conditions in case the removed device was
blocking the port from suspending.
The rechecking needs to happen *after* the device has been removed from the
bus it resides on. Otherwise when walking the port's subordinate bus in
pci_bridge_d3_update(), the device being removed would erroneously still be
taken into account.
However the device is removed from the bus_list in pci_destroy_dev() and we
currently recheck *before* that. Fix it.
Fixes: 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <mika.westerberg@linux.intel.com>
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Currently the Linux PCI core does not touch power state of PCI bridges and
PCIe ports when system suspend is entered. Leaving them in D0 consumes
power unnecessarily and may prevent the CPU from entering deeper C-states.
With recent PCIe hardware we can power down the ports to save power given
that we take into account few restrictions:
- The PCIe port hardware is recent enough, starting from 2015.
- Devices connected to PCIe ports are effectively in D3cold once the port
is transitioned to D3 (the config space is not accessible anymore and
the link may be powered down).
- Devices behind the PCIe port need to be allowed to transition to D3cold
and back. There is a way both drivers and userspace can forbid this.
- If the device behind the PCIe port is capable of waking the system it
needs to be able to do so from D3cold.
This patch adds a new flag to struct pci_device called 'bridge_d3'. This
flag is set and cleared by the PCI core whenever there is a change in power
management state of any of the devices behind the PCIe port. When system
later on is suspended we only need to check this flag and if it is true
transition the port to D3 otherwise we leave it in D0.
Also provide override mechanism via command line parameter
"pcie_port_pm=[off|force]" that can be used to disable or enable the
feature regardless of the BIOS manufacturing date.
Tested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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* pci/resource:
PCI: Simplify pci_create_attr() control flow
PCI: Don't leak memory if sysfs_create_bin_file() fails
PCI: Simplify sysfs ROM cleanup
PCI: Remove unused IORESOURCE_ROM_COPY and IORESOURCE_ROM_BIOS_COPY
MIPS: Loongson 3: Keep CPU physical (not virtual) addresses in shadow ROM resource
MIPS: Loongson 3: Use temporary struct resource * to avoid repetition
ia64/PCI: Keep CPU physical (not virtual) addresses in shadow ROM resource
ia64/PCI: Use ioremap() instead of open-coded equivalent
ia64/PCI: Use temporary struct resource * to avoid repetition
PCI: Clean up pci_map_rom() whitespace
PCI: Remove arch-specific IORESOURCE_ROM_SHADOW size from sysfs
PCI: Set ROM shadow location in arch code, not in PCI core
PCI: Don't enable/disable ROM BAR if we're using a RAM shadow copy
PCI: Don't assign or reassign immutable resources
PCI: Mark shadow copy of VGA ROM as IORESOURCE_PCI_FIXED
x86/PCI: Mark Broadwell-EP Home Agent & PCU as having non-compliant BARs
PCI: Disable IO/MEM decoding for devices with non-compliant BARs
|
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The IORESOURCE_ROM_COPY and IORESOURCE_ROM_BIOS_COPY bits are unused.
Remove them and code that depends on them.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
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Add pci_ops.{add,remove}_bus() callbacks, which will be called on every
newly created bus and when a bus is being removed, respectively. This can
be used by drivers to implement driver-specific initialization and teardown
of the bus, in addition to the architecture-specifics implemented by the
pcibios_add_bus() and the pcibios_remove_bus() functions.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
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Export the following symbols so they can be referenced by a PCI host bridge
driver compiled as a kernel loadable module:
pci_common_swizzle
pci_create_root_bus
pci_stop_root_bus
pci_remove_root_bus
pci_assign_unassigned_bus_resources
pci_fixup_irqs
Signed-off-by: Ray Jui <rjui@broadcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
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Revert commit ef83b0781a73 "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 ef83b0781a73 attempted to address
cannot happen any more after commit 8a4c5c329de7 "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 ef83b0781a73 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: ef83b0781a73 (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>
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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>
|
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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>
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Previously we removed the pci_dev from the bus_list and released its
resources in pci_destroy_dev(). But that's too early: it's possible to
call pci_destroy_dev() twice for the same device (e.g., via sysfs), and
that will cause an oops when we try to remove it from bus_list the second
time.
We should remove it from the bus_list only when the last reference to the
pci_dev has been released, i.e., in pci_release_dev().
[bhelgaas: changelog]
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
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To be consistent with 4bff6749905d ("PCI: Move device_del() from
pci_stop_dev() to pci_destroy_dev()", this changes pci_stop_root_bus()
to use device_release_driver() instead of device_del().
This also changes pci_remove_root_bus() to use device_unregister()
instead of put_device() so it corresponds with the device_register()
call in pci_create_root_bus().
[bhelgaas: changelog]
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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After commit bcdde7e221a8 (sysfs: make __sysfs_remove_dir() recursive)
I'm seeing traces analogous to the one below in Thunderbolt testing:
WARNING: CPU: 3 PID: 76 at /scratch/rafael/work/linux-pm/fs/sysfs/group.c:214 sysfs_remove_group+0x59/0xe0()
sysfs group ffffffff81c6c500 not found for kobject '0000:08'
Modules linked in: ...
CPU: 3 PID: 76 Comm: kworker/u16:7 Not tainted 3.13.0-rc1+ #76
Hardware name: Acer Aspire S5-391/Venus , BIOS V1.02 05/29/2012
Workqueue: kacpi_hotplug acpi_hotplug_work_fn
0000000000000009 ffff8801644b9ac8 ffffffff816b23bf 0000000000000007
ffff8801644b9b18 ffff8801644b9b08 ffffffff81046607 ffff88016925b800
0000000000000000 ffffffff81c6c500 ffff88016924f928 ffff88016924f800
Call Trace:
[<ffffffff816b23bf>] dump_stack+0x4e/0x71
[<ffffffff81046607>] warn_slowpath_common+0x87/0xb0
[<ffffffff810466d1>] warn_slowpath_fmt+0x41/0x50
[<ffffffff811e42ef>] ? sysfs_get_dirent_ns+0x6f/0x80
[<ffffffff811e5389>] sysfs_remove_group+0x59/0xe0
[<ffffffff8149f00b>] dpm_sysfs_remove+0x3b/0x50
[<ffffffff81495818>] device_del+0x58/0x1c0
[<ffffffff814959c8>] device_unregister+0x48/0x60
[<ffffffff813254fe>] pci_remove_bus+0x6e/0x80
[<ffffffff81325548>] pci_remove_bus_device+0x38/0x110
[<ffffffff8132555d>] pci_remove_bus_device+0x4d/0x110
[<ffffffff81325639>] pci_stop_and_remove_bus_device+0x19/0x20
[<ffffffff813418d0>] disable_slot+0x20/0xe0
[<ffffffff81341a38>] acpiphp_check_bridge+0xa8/0xd0
[<ffffffff813427ad>] hotplug_event+0x17d/0x220
[<ffffffff81342880>] hotplug_event_work+0x30/0x70
[<ffffffff8136d665>] acpi_hotplug_work_fn+0x18/0x24
[<ffffffff81061331>] process_one_work+0x261/0x450
[<ffffffff81061a7e>] worker_thread+0x21e/0x370
[<ffffffff81061860>] ? rescuer_thread+0x300/0x300
[<ffffffff81068342>] kthread+0xd2/0xe0
[<ffffffff81068270>] ? flush_kthread_worker+0x70/0x70
[<ffffffff816c19bc>] ret_from_fork+0x7c/0xb0
[<ffffffff81068270>] ? flush_kthread_worker+0x70/0x70
(Mika Westerberg sees them too in his tests).
Some investigation documented in kernel bug #65281 led me to the
conclusion that the source of the problem is the device_del() in
pci_stop_dev() as it now causes the sysfs directory of the device to be
removed recursively along with all of its subdirectories. That includes
the sysfs directory of the device's subordinate bus (dev->subordinate) and
its "power" group.
Consequently, when pci_remove_bus() is called for dev->subordinate in
pci_remove_bus_device(), it calls device_unregister(&bus->dev), but at this
point the sysfs directory of bus->dev doesn't exist any more and its
"power" group doesn't exist either. Thus, when dpm_sysfs_remove() called
from device_del() tries to remove that group, it triggers the above
warning.
That indicates a logical mistake in the design of
pci_stop_and_remove_bus_device(), which causes bus device objects to be
left behind their parents (bridge device objects) and can be fixed by
moving the device_del() from pci_stop_dev() into pci_destroy_dev(), so
pci_remove_bus() can be called for the device's subordinate bus before the
device itself is unregistered from the hierarchy. Still, the driver, if
any, should be detached from the device in pci_stop_dev(), so use
device_release_driver() directly from there.
References: https://bugzilla.kernel.org/show_bug.cgi?id=65281#c6
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
|
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Fix whitespace, capitalization, and spelling errors. No functional change.
I know "busses" is not an error, but "buses" was more common, so I used it
consistently.
Signed-off-by: Marta Rybczynska <rybczynska@gmail.com> (pci_reset_bridge_secondary_bus())
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
|
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On ACPI-based platforms, the pci_slot driver creates PCI slot devices
according to information from ACPI tables by registering an ACPI PCI
subdriver. The ACPI PCI subdriver will only be called when creating/
destroying PCI root buses, and it won't be called when hot-plugging
P2P bridges. It may cause stale PCI slot devices after hot-removing
a P2P bridge if that bridge has associated PCI slots. And the acpiphp
driver has the same issue too.
This patch introduces two hook points into the PCI core, which will
be invoked when creating/destroying PCI buses for PCI host and P2P
bridges. They could be used to setup/destroy platform dependent stuff
in a unified way, both at boot time and for PCI hotplug operations.
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Yinghai Lu <yinghai@kernel.org>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Myron Stowe <myron.stowe@redhat.com>
|
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We always call device_register() and pci_create_legacy_files() for a
new bus before handing out the "struct pci_bus *". Therefore, there's
no possiblity of removing the bus with pci_remove_bus() before those
calls have been made, so we don't need to check "bus->is_added" before
calling pci_remove_legacy_files() and device_unregister().
[bhelgaas: changelog]
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Yinghai Lu <yinghai@kernel.org>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Toshi Kani <toshi.kani@hp.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci
Pull PCI changes from Bjorn Helgaas:
"Host bridge hotplug
- Major overhaul of ACPI host bridge add/start (Rafael Wysocki, Yinghai Lu)
- Major overhaul of PCI/ACPI binding (Rafael Wysocki, Yinghai Lu)
- Split out ACPI host bridge and ACPI PCI device hotplug (Yinghai Lu)
- Stop caching _PRT and make independent of bus numbers (Yinghai Lu)
PCI device hotplug
- Clean up cpqphp dead code (Sasha Levin)
- Disable ARI unless device and upstream bridge support it (Yijing Wang)
- Initialize all hot-added devices (not functions 0-7) (Yijing Wang)
Power management
- Don't touch ASPM if disabled (Joe Lawrence)
- Fix ASPM link state management (Myron Stowe)
Miscellaneous
- Fix PCI_EXP_FLAGS accessor (Alex Williamson)
- Disable Bus Master in pci_device_shutdown (Konstantin Khlebnikov)
- Document hotplug resource and MPS parameters (Yijing Wang)
- Add accessor for PCIe capabilities (Myron Stowe)
- Drop pciehp suspend/resume messages (Paul Bolle)
- Make pci_slot built-in only (not a module) (Jiang Liu)
- Remove unused PCI/ACPI bind ops (Jiang Liu)
- Removed used pci_root_bus (Bjorn Helgaas)"
* tag 'pci-v3.9-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (51 commits)
PCI/ACPI: Don't cache _PRT, and don't associate them with bus numbers
PCI: Fix PCI Express Capability accessors for PCI_EXP_FLAGS
ACPI / PCI: Make pci_slot built-in only, not a module
PCI/PM: Clear state_saved during suspend
PCI: Use atomic_inc_return() rather than atomic_add_return()
PCI: Catch attempts to disable already-disabled devices
PCI: Disable Bus Master unconditionally in pci_device_shutdown()
PCI: acpiphp: Remove dead code for PCI host bridge hotplug
PCI: acpiphp: Create companion ACPI devices before creating PCI devices
PCI: Remove unused "rc" in virtfn_add_bus()
PCI: pciehp: Drop suspend/resume ENTRY messages
PCI/ASPM: Don't touch ASPM if forcibly disabled
PCI/ASPM: Deallocate upstream link state even if device is not PCIe
PCI: Document MPS parameters pci=pcie_bus_safe, pci=pcie_bus_perf, etc
PCI: Document hpiosize= and hpmemsize= resource reservation parameters
PCI: Use PCI Express Capability accessor
PCI: Introduce accessor to retrieve PCIe Capabilities Register
PCI: Put pci_dev in device tree as early as possible
PCI: Skip attaching driver in device_add()
PCI: acpiphp: Keep driver loaded even if no slots found
...
|
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Devices are added to pci_pme_list when drivers use pci_enable_wake()
or pci_wake_from_d3(), but they aren't removed from the list unless
the driver explicitly disables wakeup. Many drivers never disable
wakeup, so their devices remain on the list even after they are
removed, e.g., via hotplug. A subsequent PME poll will oops when
it tries to touch the device.
This patch disables PME# on a device before removing it, which removes
the device from pci_pme_list. This is safe even if the device never
had PME# enabled.
This oops can be triggered by unplugging a Thunderbolt ethernet adapter
on a Macbook Pro, as reported by Daniel below.
[bhelgaas: changelog]
Reference: http://lkml.kernel.org/r/CAMVG2svG21yiM1wkH4_2pen2n+cr2-Zv7TbH3Gj+8MwevZjDbw@mail.gmail.com
Reported-and-tested-by: Daniel J Blueman <daniel@quora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org
|
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According to device model documentation, the way to create/destroy PCI
devices should be symmetric. The rule is to either use
1) device_register()/device_unregister()
or
2) device_initialize()/device_add()/device_del()/put_device().
So change PCI core logic to follow the rule and get rid of the redundant
pci_dev_get()/pci_dev_put() pair.
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
|
|
It supports both PCI root bus and PCI bus under PCI bridge.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
|
|
This restores the previous behavior of stopping all child devices before
removing any of them. The current SR-IOV design, where removing the PF
also drops references on all the VFs, depends on having the VFs continue
to exist after having been stopped.
[bhelgaas: changelog]
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
|
|
list_del() already sets next/prev to LIST_POISON1/LIST_POISON2, so we
don't need to do anything special here to prevent further list accesses.
Tested-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
|
|
"bus" is the conventional name for a "struct pci_bus *" variable.
Tested-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
|
|
This removes unused code that was already commented out.
Tested-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
|
|
Previously, when we removed a PCI device, we made two passes over the
hierarchy rooted at the device. In the first pass, we stopped all
the devices, and in the second, we removed them.
This patch combines the two passes into one so that we remove a device as
soon as it and all its children have been stopped.
Note that we previously stopped devices in reverse order and removed them
in forward order. Now we stop and remove them in reverse order.
Tested-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
|
|
pci_stop_bus_devices() is only two lines of code and is only called by
pci_stop_bus_device(), so I think it's easier to read if we just fold it
into the caller. Similarly for __pci_remove_behind_bridge().
Tested-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
|
|
Replace list_for_each() + pci_dev_b() with the simpler
list_for_each_entry().
Tested-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
|
|
The PCMCIA CardBus driver was the only user of
pci_stop_and_remove_behind_bridge(), and it now uses
pci_stop_and_remove_bus_device() instead, so remove this interface.
This removes exported symbol pci_stop_and_remove_behind_bridge.
Tested-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
|
|
The acpiphp hotplug driver was the only user of pci_stop_bus_device() and
__pci_remove_bus_device(), and it now uses pci_stop_and_remove_bus_device()
instead, so stop exposing these interfaces.
This removes these exported symbols:
__pci_remove_bus_device
pci_stop_bus_device
Tested-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
|
|
Release bus number resource when removing a bus.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
|
|
Don't switch to pci_remove_bus_device yet, keep the __ prefix for now
(the behavior is still the same: remove without stopping first).
This allows other out of tree users or pending patches to get notified
from compiler warning.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
|
|
The old pci_remove_behind_bridge actually do stop and remove.
Make the name reflect that to reduce confusion.
Suggested-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
|
|
The old pci_remove_bus_device actually did stop and remove.
Make the name reflect that to reduce confusion.
This patch is done by sed scripts and changes back some incorrect
__pci_remove_bus_device changes.
Suggested-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
|
|
When hot removing a pci express module that has a pcie switch and supports
SRIOV, we got:
[ 5918.610127] pciehp 0000:80:02.2:pcie04: pcie_isr: intr_loc 1
[ 5918.615779] pciehp 0000:80:02.2:pcie04: Attention button interrupt received
[ 5918.622730] pciehp 0000:80:02.2:pcie04: Button pressed on Slot(3)
[ 5918.629002] pciehp 0000:80:02.2:pcie04: pciehp_get_power_status: SLOTCTRL a8 value read 1f9
[ 5918.637416] pciehp 0000:80:02.2:pcie04: PCI slot #3 - powering off due to button press.
[ 5918.647125] pciehp 0000:80:02.2:pcie04: pcie_isr: intr_loc 10
[ 5918.653039] pciehp 0000:80:02.2:pcie04: pciehp_green_led_blink: SLOTCTRL a8 write cmd 200
[ 5918.661229] pciehp 0000:80:02.2:pcie04: pciehp_set_attention_status: SLOTCTRL a8 write cmd c0
[ 5924.667627] pciehp 0000:80:02.2:pcie04: Disabling domain:bus:device=0000:b0:00
[ 5924.674909] pciehp 0000:80:02.2:pcie04: pciehp_get_power_status: SLOTCTRL a8 value read 2f9
[ 5924.683262] pciehp 0000:80:02.2:pcie04: pciehp_unconfigure_device: domain:bus:dev = 0000:b0:00
[ 5924.693976] libfcoe_device_notification: NETDEV_UNREGISTER eth6
[ 5924.764979] libfcoe_device_notification: NETDEV_UNREGISTER eth14
[ 5924.873539] libfcoe_device_notification: NETDEV_UNREGISTER eth15
[ 5924.995209] libfcoe_device_notification: NETDEV_UNREGISTER eth16
[ 5926.114407] sxge 0000:b2:00.0: PCI INT A disabled
[ 5926.119342] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 5926.127189] IP: [<ffffffff81353a3b>] pci_stop_bus_device+0x33/0x83
[ 5926.133377] PGD 0
[ 5926.135402] Oops: 0000 [#1] SMP
[ 5926.138659] CPU 2
[ 5926.140499] Modules linked in:
...
[ 5926.143754]
[ 5926.275823] Call Trace:
[ 5926.278267] [<ffffffff81353a38>] pci_stop_bus_device+0x30/0x83
[ 5926.284180] [<ffffffff81353af4>] pci_remove_bus_device+0x1a/0xba
[ 5926.290264] [<ffffffff81366311>] pciehp_unconfigure_device+0x110/0x17b
[ 5926.296866] [<ffffffff81365dd9>] ? pciehp_disable_slot+0x188/0x188
[ 5926.303123] [<ffffffff81365d6f>] pciehp_disable_slot+0x11e/0x188
[ 5926.309206] [<ffffffff81365e68>] pciehp_power_thread+0x8f/0xe0
...
+-[0000:80]-+-00.0-[81-8f]--
| +-01.0-[90-9f]--
| +-02.0-[a0-af]--
| +-02.2-[b0-bf]----00.0-[b1-b3]--+-02.0-[b2]--+-00.0 Device
| | | +-00.1 Device
| | | +-00.2 Device
| | | \-00.3 Device
| | \-03.0-[b3]--+-00.0 Device
| | +-00.1 Device
| | +-00.2 Device
| | \-00.3 Device
root complex: 80:02.2
pci express modules: have pcie switch and are listed as b0:00.0, b1:02.0 and b1:03.0.
end devices are b2:00.0 and b3.00.0.
VFs are: b2:00.1,... b2:00.3, and b3:00.1,...,b3:00.3
Root cause: when doing pci_stop_bus_device() with phys fn, it will stop
virt fn and remove the fn, so
list_for_each_safe(l, n, &bus->devices)
will have problem to refer freed n that is pointed to vf entry.
Solution is just replacing list_for_each_safe() with
list_for_each_prev_safe(). This will make sure we can get valid n pointer
to PF instead of the freed VF pointer (because newly added devices are
inserted to the bus->devices list tail).
During reviewing the patch, Bjorn said:
| The PCI hot-remove path calls pci_stop_bus_devices() via
| pci_remove_bus_device().
|
| pci_stop_bus_devices() traverses the bus->devices list (point A below),
| stopping each device in turn, which calls the driver remove() method. When
| the device is an SR-IOV PF, the driver calls pci_disable_sriov(), which
| also uses pci_remove_bus_device() to remove the VF devices from the
| bus->devices list (point B).
|
| pci_remove_bus_device
| pci_stop_bus_device
| pci_stop_bus_devices(subordinate)
| list_for_each(bus->devices) <-- A
| pci_stop_bus_device(PF)
| ...
| driver->remove
| pci_disable_sriov
| ...
| pci_remove_bus_device(VF)
| <remove from bus_list> <-- B
|
| At B, we're changing the same list we're iterating through at A, so when
| the driver remove() method returns, the pci_stop_bus_devices() iterator has
| a pointer to a list entry that has already been freed.
Discussion thread can be found : https://lkml.org/lkml/2011/10/15/141
https://lkml.org/lkml/2012/1/23/360
-v5: According to Linus to make remove more robust, Change to
list_for_each_prev_safe instead. That is more reasonable, because
those devices are added to tail of the list before.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
|
