commit f5eff5591b8f9c5effd25c92c758a127765f74c1 upstream.
In 2013, commits
2e35afaefe64 ("PCI: pciehp: Add reset_slot() method")
608c388122c7 ("PCI: Add slot reset option to pci_dev_reset()")
amended PCIe hotplug to mask Presence Detect Changed events during a
Secondary Bus Reset. The reset thus no longer causes gratuitous slot
bringdown and bringup.
However the commits neglected to serialize reset with code paths reading
slot registers. For instance, a slot bringup due to an earlier hotplug
event may see the Presence Detect State bit cleared during a concurrent
Secondary Bus Reset.
In 2018, commit
5b3f7b7d062b ("PCI: pciehp: Avoid slot access during reset")
retrofitted the missing locking. It introduced a reset_lock which
serializes a Secondary Bus Reset with other parts of pciehp.
Unfortunately the locking turns out to be overzealous: reset_lock is
held for the entire enumeration and de-enumeration of hotplugged devices,
including driver binding and unbinding.
Driver binding and unbinding acquires device_lock while the reset_lock
of the ancestral hotplug port is held. A concurrent Secondary Bus Reset
acquires the ancestral reset_lock while already holding the device_lock.
The asymmetric locking order in the two code paths can lead to AB-BA
deadlocks.
Michael Haeuptle reports such deadlocks on simultaneous hot-removal and
vfio release (the latter implies a Secondary Bus Reset):
pciehp_ist() # down_read(reset_lock)
pciehp_handle_presence_or_link_change()
pciehp_disable_slot()
__pciehp_disable_slot()
remove_board()
pciehp_unconfigure_device()
pci_stop_and_remove_bus_device()
pci_stop_bus_device()
pci_stop_dev()
device_release_driver()
device_release_driver_internal()
__device_driver_lock() # device_lock()
SYS_munmap()
vfio_device_fops_release()
vfio_device_group_close()
vfio_device_close()
vfio_device_last_close()
vfio_pci_core_close_device()
vfio_pci_core_disable() # device_lock()
__pci_reset_function_locked()
pci_reset_bus_function()
pci_dev_reset_slot_function()
pci_reset_hotplug_slot()
pciehp_reset_slot() # down_write(reset_lock)
Ian May reports the same deadlock on simultaneous hot-removal and an
AER-induced Secondary Bus Reset:
aer_recover_work_func()
pcie_do_recovery()
aer_root_reset()
pci_bus_error_reset()
pci_slot_reset()
pci_slot_lock() # device_lock()
pci_reset_hotplug_slot()
pciehp_reset_slot() # down_write(reset_lock)
Fix by releasing the reset_lock during driver binding and unbinding,
thereby splitting and shrinking the critical section.
Driver binding and unbinding is protected by the device_lock() and thus
serialized with a Secondary Bus Reset. There's no need to additionally
protect it with the reset_lock. However, pciehp does not bind and
unbind devices directly, but rather invokes PCI core functions which
also perform certain enumeration and de-enumeration steps.
The reset_lock's purpose is to protect slot registers, not enumeration
and de-enumeration of hotplugged devices. That would arguably be the
job of the PCI core, not the PCIe hotplug driver. After all, an
AER-induced Secondary Bus Reset may as well happen during boot-time
enumeration of the PCI hierarchy and there's no locking to prevent that
either.
Exempting *de-enumeration* from the reset_lock is relatively harmless:
A concurrent Secondary Bus Reset may foil config space accesses such as
PME interrupt disablement. But if the device is physically gone, those
accesses are pointless anyway. If the device is physically present and
only logically removed through an Attention Button press or the sysfs
"power" attribute, PME interrupts as well as DMA cannot come through
because pciehp_unconfigure_device() disables INTx and Bus Master bits.
That's still protected by the reset_lock in the present commit.
Exempting *enumeration* from the reset_lock also has limited impact:
The exempted call to pci_bus_add_device() may perform device accesses
through pcibios_bus_add_device() and pci_fixup_device() which are now
no longer protected from a concurrent Secondary Bus Reset. Otherwise
there should be no impact.
In essence, the present commit seeks to fix the AB-BA deadlocks while
still retaining a best-effort reset protection for enumeration and
de-enumeration of hotplugged devices -- until a general solution is
implemented in the PCI core.
Link: https://lore.kernel.org/linux-pci/CS1PR8401MB0728FC6FDAB8A35C22BD90EC95F10@CS1PR8401MB0728.NAMPRD84.PROD.OUTLOOK.COM
Link: https://lore.kernel.org/linux-pci/20200615143250.438252-1-ian.may@canonical.com
Link: https://lore.kernel.org/linux-pci/ce878dab-c0c4-5bd0-a725-9805a075682d@amd.com
Link: https://lore.kernel.org/linux-pci/ed831249-384a-6d35-0831-70af191e9bce@huawei.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215590
Fixes: 5b3f7b7d062b ("PCI: pciehp: Avoid slot access during reset")
Link: https://lore.kernel.org/r/fef2b2e9edf245c049a8c5b94743c0f74ff5008a.1681191902.git.lukas@wunner.de
Reported-by: Michael Haeuptle <michael.haeuptle@hpe.com>
Reported-by: Ian May <ian.may@canonical.com>
Reported-by: Andrey Grodzovsky <andrey2805@gmail.com>
Reported-by: Rahul Kumar <rahul.kumar1@amd.com>
Reported-by: Jialin Zhang <zhangjialin11@huawei.com>
Tested-by: Anatoli Antonovitch <Anatoli.Antonovitch@amd.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org # v4.19+
Cc: Dan Stein <dstein@hpe.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Alex Michon <amichon@kalrayinc.com>
Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Sathyanarayanan Kuppuswamy <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
- Remove MODULE_LICENSE from boolean drivers so they don't look like modules so modprobe will complain about them (Nick Alcock) * pci/kbuild: PCI: Remove MODULE_LICENSE so boolean drivers don't look like modules
Since 8b41fc4454e3 ("kbuild: create modules.builtin without
Makefile.modbuiltin or tristate.conf"), MODULE_LICENSE declarations are
used to identify modules. As a consequence, MODULE_LICENSE in non-modules
causes modprobe to misidentify the object file as a module when it is not,
and modprobe might succeed rather than failing with a suitable error
message.
For tristate modules that can be either built-in or loaded at runtime,
modprobe succeeds in both cases:
# modprobe ext4
[exit status zero if CONFIG_EXT4_FS=y or =m]
For boolean modules like the Standard Hot Plug Controller driver (shpchp)
that cannot be loaded at runtime, modprobe should always fail like this:
# modprobe shpchp
modprobe: FATAL: Module shpchp not found in directory /lib/modules/...
[exit status non-zero regardless of CONFIG_HOTPLUG_PCI_SHPC]
but prior to this commit, shpchp_core.c contained MODULE_LICENSE, so
"modprobe shpchp" silently succeeded when it should have failed.
Remove MODULE_LICENSE in files that cannot be built as modules.
[bhelgaas: commit log, squash]
Suggested-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20230216152410.4312-1-nick.alcock@oracle.com/
Signed-off-by: Nick Alcock <nick.alcock@oracle.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Hitomi Hasegawa <hasegawa-hitomi@fujitsu.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>
The Qualcomm PCI bridge device (Device ID 0x010e) found in chipsets such as SC8280XP used in Lenovo Thinkpad X13s, does not set the Command Completed bit unless writes to the Slot Command register change "Control" bits. This results in timeouts like below during boot and resume from suspend: pcieport 0002:00:00.0: pciehp: Timeout on hotplug command 0x03c0 (issued 2020 msec ago) ... pcieport 0002:00:00.0: pciehp: Timeout on hotplug command 0x13f1 (issued 107724 msec ago) Add the device to the Command Completed quirk to mark commands "completed" immediately unless they change the "Control" bits. Link: https://lore.kernel.org/r/20230213144922.89982-1-manivannan.sadhasivam@linaro.org Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
The No Command Completed Support bit in the Slot Capabilities register indicates whether Command Completed Interrupt Enable is unsupported. We already check whether No Command Completed Support bit is set in pcie_wait_cmd(), and do not wait in this case. Don't enable this Command Completed Interrupt at all if NCCS is set, so that when users dump configuration space from userspace, the dump does not confuse them by saying that Command Completed Interrupt is not supported, but it is enabled. Link: https://lore.kernel.org/r/20220927141926.8895-2-kabel@kernel.org Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Marek Behún <kabel@kernel.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Lukas Wunner <lukas@wunner.de>
The ->get_mode1_ECC_cap callback in the shpchp_hpc_ops struct is never called, so remove it. [bhelgaas: squash] Link: https://lore.kernel.org/r/20221112142859.319733-2-ian@linux.cowan.aero Link: https://lore.kernel.org/r/20221112142859.319733-3-ian@linux.cowan.aero Link: https://lore.kernel.org/r/20221112142859.319733-4-ian@linux.cowan.aero Signed-off-by: Ian Cowan <ian@linux.cowan.aero> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
It is reported that on some systems pciehp binds to an Upstream Port and attempts to operate it which causes devices below the Port to disappear from the bus. This happens because acpiphp sets dev->is_hotplug_bridge for that Port (after receiving a Device Check notification on it from the platform firmware via ACPI) during the enumeration of PCI devices. get_port_device_capability() sees that dev->is_hotplug_bridge is set and adds PCIE_PORT_SERVICE_HP to Port services, which allows pciehp to bind to the Port in question. Even though this particular problem can be addressed by making the portdrv_core checks more robust, it also causes power management to work differently on the affected systems which generally is not desirable (PCIe Ports with dev->is_hotplug_bridge set have to pass additional tests to be allowed to go into the D3hot/cold power states which affects runtime PM of devices below these Ports). For this reason, amend check_hotplug_bridge() with a PCIe type check to prevent it from setting dev->is_hotplug_bridge for Upstream Ports. Suggested-by: Lukas Wunner <lukas@wunner.de> Link: https://lore.kernel.org/r/2262230.ElGaqSPkdT@kreacher Reported-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Tested-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Reviewed-by: Lukas Wunner <lukas@wunner.de>
Thunderbolt/USB4 PCIe tunneling depends on native PCIe hotplug. Enable pciehp by default if USB4 is enabled. [bhelgaas: squash, update subject, commit logs, tidy whitespace] Link: https://lore.kernel.org/r/20221115113857.35800-2-albert.zhou.50@gmail.com Link: https://lore.kernel.org/r/20221115113857.35800-3-albert.zhou.50@gmail.com Signed-off-by: Albert Zhou <albert.zhou.50@gmail.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
arch/powerpc/include/asm/prom.h includes some headers that it doesn't need itself. Add the missing headers to files that include prom.h so we can remove them from prom.h. Link: https://lore.kernel.org/r/79201f5fae8d003164ac36ed3be7789db1bc5ab4.1648833421.git.christophe.leroy@csgroup.eu Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Pull pci updates from Bjorn Helgaas:
"Enumeration:
- Move the VGA arbiter from drivers/gpu to drivers/pci because it's
PCI-specific, not GPU-specific (Bjorn Helgaas)
- Select the default VGA device consistently whether it's enumerated
before or after VGA arbiter init, which fixes arches that enumerate
PCI devices late (Huacai Chen)
Resource management:
- Support BAR sizes up to 8TB (Dongdong Liu)
PCIe native device hotplug:
- Fix "Command Completed" tracking to avoid spurious timouts when
powering off empty slots (Liguang Zhang)
- Quirk Qualcomm devices that don't implement Command Completed
correctly, again to avoid spurious timeouts (Manivannan Sadhasivam)
Peer-to-peer DMA:
- Add Intel 3rd Gen Intel Xeon Scalable Processors to whitelist
(Michael J. Ruhl)
APM X-Gene PCIe controller driver:
- Revert generic DT parsing changes that broke some machines in the
field (Marc Zyngier)
Freescale i.MX6 PCIe controller driver:
- Allow controller probe to succeed even when no devices currently
present to allow hot-add later (Fabio Estevam)
- Enable power management on i.MX6QP (Richard Zhu)
- Assert CLKREQ# on i.MX8MM so enumeration doesn't hang when no
device is connected (Richard Zhu)
Marvell Aardvark PCIe controller driver:
- Fix MSI and MSI-X support (Marek Behún, Pali Rohár)
- Add support for ERR and PME interrupts (Pali Rohár)
Marvell MVEBU PCIe controller driver:
- Add DT binding and support for "num-lanes" (Pali Rohár)
- Add support for INTx interrupts (Pali Rohár)
Microsoft Hyper-V host bridge driver:
- Avoid unnecessary hypercalls when unmasking IRQs on ARM64 (Boqun
Feng)
Qualcomm PCIe controller driver:
- Add SM8450 DT binding and driver support (Dmitry Baryshkov)
Renesas R-Car PCIe controller driver:
- Help the controller get to the L1 state since the hardware can't do
it on its own (Marek Vasut)
- Return PCI_ERROR_RESPONSE (~0) for reads that fail on PCIe (Marek
Vasut)
SiFive FU740 PCIe controller driver:
- Drop redundant '-gpios' from DT GPIO lookup (Ben Dooks)
- Force 2.5GT/s for initial device probe (Ben Dooks)
Socionext UniPhier Pro5 controller driver:
- Add NX1 DT binding and driver support (Kunihiko Hayashi)
Synopsys DesignWare PCIe controller driver:
- Restore MSI configuration so MSI works after resume (Jisheng
Zhang)"
* tag 'pci-v5.18-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (94 commits)
x86/PCI: Add #includes to asm/pci_x86.h
PCI: ibmphp: Remove unused assignments
PCI: cpqphp: Remove unused assignments
PCI: fu740: Remove unused assignments
PCI: kirin: Remove unused assignments
PCI: Remove unused assignments
PCI: Declare pci_filp_private only when HAVE_PCI_MMAP
PCI: Avoid broken MSI on SB600 USB devices
PCI: fu740: Force 2.5GT/s for initial device probe
PCI: xgene: Revert "PCI: xgene: Fix IB window setup"
PCI: xgene: Revert "PCI: xgene: Use inbound resources for setup"
PCI: imx6: Assert i.MX8MM CLKREQ# even if no device present
PCI: imx6: Invoke the PHY exit function after PHY power off
PCI: rcar: Use PCI_SET_ERROR_RESPONSE after read which triggered an exception
PCI: rcar: Finish transition to L1 state in rcar_pcie_config_access()
PCI: dwc: Restore MSI Receiver mask during resume
PCI: fu740: Drop redundant '-gpios' from DT GPIO lookup
PCI/VGA: Replace full MIT license text with SPDX identifier
PCI/VGA: Use unsigned format string to print lock counts
PCI/VGA: Log bridge control messages when adding devices
...