It is preferred to use typed property access functions (i.e.
of_property_read_<type> functions) rather than low-level
of_get_property()/of_find_property() functions for reading properties. As
part of this, convert of_get_property()/of_find_property() calls to the
recently added of_property_present() helper when we just want to test for
presence of a property and nothing more.
Link: https://lore.kernel.org/r/20230310144719.1544443-1-robh@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> # pcie-mediatek
In 2013, commits
2e35afaefe ("PCI: pciehp: Add reset_slot() method")
608c388122 ("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
5b3f7b7d06 ("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: 5b3f7b7d06 ("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>
Refactor pci_bus_for_each_resource() in the same way as
pci_dev_for_each_resource(). This allows the index to be hidden inside the
implementation so the caller can omit it when it's not used otherwise.
No functional changes intended.
Link: https://lore.kernel.org/r/20230330162434.35055-6-andriy.shevchenko@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>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.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 8b41fc4454 ("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>
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>
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Merge tag 'pci-v5.18-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci
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
...
- Clear pciehp cmd_busy bit when command completes in polling mode to avoid
spurious timeouts (Liguang Zhang)
- Add quirk to work around Qualcomm hardware defect in Command Completed
signaling (Manivannan Sadhasivam)
* pci/hotplug:
PCI: pciehp: Add Qualcomm quirk for Command Completed erratum
PCI: pciehp: Clear cmd_busy bit in polling mode
- Add and use #defines for normal and subtractive PCI bridges (Pali Rohár)
- Set all 24 bits of PCI class code for iproc (Pali Rohár)
* pci/bridge-class-codes:
PCI: iproc: Set all 24 bits of PCI class code
PCI: Add defines for normal and subtractive PCI bridges
Remove variables and assignments that are never used.
Found by Krzysztof using cppcheck, e.g.:
$ cppcheck --enable=all --force
unreadVariable drivers/pci/hotplug/ibmphp_res.c:1958 Variable 'bus_sec' is assigned a value that is never used.
Reported-by: Krzysztof Wilczyński <kw@linux.com>
Link: https://lore.kernel.org/r/20220313192933.434746-6-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Remove variables and assignments that are never used.
Found by Krzysztof using cppcheck, e.g.:
$ cppcheck --enable=all --force
unreadVariable drivers/pci/hotplug/cpqphp_core.c:1257 Variable 'rc' is assigned a value that is never used.
Reported-by: Krzysztof Wilczyński <kw@linux.com>
Link: https://lore.kernel.org/r/20220313192933.434746-5-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Add these PCI class codes to pci_ids.h:
PCI_CLASS_BRIDGE_PCI_NORMAL
PCI_CLASS_BRIDGE_PCI_SUBTRACTIVE
Use these defines in all kernel code for describing PCI class codes for
normal and subtractive PCI bridges.
[bhelgaas: similar change in pci-mvebu.c]
Link: https://lore.kernel.org/r/20220214114109.26809-1-pali@kernel.org
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
The Qualcomm PCI bridge device (Device ID 0x0110) found in chipsets such as
SM8450 does not set the Command Completed bit unless writes to the Slot
Command register change "Control" bits.
This results in timeouts like below:
pcieport 0001:00:00.0: pciehp: Timeout on hotplug command 0x03c0 (issued 2020 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/20220210145003.135907-1-manivannan.sadhasivam@linaro.org
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Replace acpi_bus_get_device() that is going to be dropped with
acpi_fetch_acpi_dev().
No intentional functional impact.
Link: https://lore.kernel.org/r/11930209.O9o76ZdvQC@kreacher
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Writes to a Downstream Port's Slot Control register are PCIe hotplug
"commands." If the Port supports Command Completed events, software must
wait for a command to complete before writing to Slot Control again.
pcie_do_write_cmd() sets ctrl->cmd_busy when it writes to Slot Control. If
software notification is enabled, i.e., PCI_EXP_SLTCTL_HPIE and
PCI_EXP_SLTCTL_CCIE are set, ctrl->cmd_busy is cleared by pciehp_isr().
But when software notification is disabled, as it is when pcie_init()
powers off an empty slot, pcie_wait_cmd() uses pcie_poll_cmd() to poll for
command completion, and it neglects to clear ctrl->cmd_busy, which leads to
spurious timeouts:
pcieport 0000:00:03.0: pciehp: Timeout on hotplug command 0x01c0 (issued 2264 msec ago)
pcieport 0000:00:03.0: pciehp: Timeout on hotplug command 0x05c0 (issued 2288 msec ago)
Clear ctrl->cmd_busy in pcie_poll_cmd() when it detects a Command Completed
event (PCI_EXP_SLTSTA_CC).
[bhelgaas: commit log]
Fixes: a5dd4b4b05 ("PCI: pciehp: Wait for hotplug command completion where necessary")
Link: https://lore.kernel.org/r/20211111054258.7309-1-zhangliguang@linux.alibaba.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215143
Link: https://lore.kernel.org/r/20211126173309.GA12255@wunner.de
Signed-off-by: Liguang Zhang <zhangliguang@linux.alibaba.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org # v4.19+
- Add PCI_ERROR_RESPONSE and related definitions for signaling and checking
for transaction errors on PCI (Naveen Naidu)
- Fabricate PCI_ERROR_RESPONSE data (~0) in config read wrappers, instead
of in host controller drivers, when transactions fail on PCI (Naveen
Naidu)
- Use PCI_POSSIBLE_ERROR() to check for possible failure of config reads
(Naveen Naidu)
* pci/errors:
PCI: xgene: Use PCI_ERROR_RESPONSE to identify config read errors
PCI: hv: Use PCI_ERROR_RESPONSE to identify config read errors
PCI: keystone: Use PCI_ERROR_RESPONSE to identify config read errors
PCI: Use PCI_ERROR_RESPONSE to identify config read errors
PCI: cpqphp: Use PCI_POSSIBLE_ERROR() to check config reads
PCI/PME: Use PCI_POSSIBLE_ERROR() to check config reads
PCI/DPC: Use PCI_POSSIBLE_ERROR() to check config reads
PCI: pciehp: Use PCI_POSSIBLE_ERROR() to check config reads
PCI: vmd: Use PCI_POSSIBLE_ERROR() to check config reads
PCI/ERR: Use PCI_POSSIBLE_ERROR() to check config reads
PCI: rockchip-host: Drop error data fabrication when config read fails
PCI: rcar-host: Drop error data fabrication when config read fails
PCI: altera: Drop error data fabrication when config read fails
PCI: mvebu: Drop error data fabrication when config read fails
PCI: aardvark: Drop error data fabrication when config read fails
PCI: kirin: Drop error data fabrication when config read fails
PCI: histb: Drop error data fabrication when config read fails
PCI: exynos: Drop error data fabrication when config read fails
PCI: mediatek: Drop error data fabrication when config read fails
PCI: iproc: Drop error data fabrication when config read fails
PCI: thunder: Drop error data fabrication when config read fails
PCI: Drop error data fabrication when config read fails
PCI: Use PCI_SET_ERROR_RESPONSE() for disconnected devices
PCI: Set error response data when config read fails
PCI: Add PCI_ERROR_RESPONSE and related definitions
Use down_read_nested() and down_write_nested() when taking the
ctrl->reset_lock rw-sem, passing the number of PCIe hotplug controllers in
the path to the PCI root bus as lock subclass parameter.
This fixes the following false-positive lockdep report when unplugging a
Lenovo X1C8 from a Lenovo 2nd gen TB3 dock:
pcieport 0000:06:01.0: pciehp: Slot(1): Link Down
pcieport 0000:06:01.0: pciehp: Slot(1): Card not present
============================================
WARNING: possible recursive locking detected
5.16.0-rc2+ #621 Not tainted
--------------------------------------------
irq/124-pciehp/86 is trying to acquire lock:
ffff8e5ac4299ef8 (&ctrl->reset_lock){.+.+}-{3:3}, at: pciehp_check_presence+0x23/0x80
but task is already holding lock:
ffff8e5ac4298af8 (&ctrl->reset_lock){.+.+}-{3:3}, at: pciehp_ist+0xf3/0x180
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&ctrl->reset_lock);
lock(&ctrl->reset_lock);
*** DEADLOCK ***
May be due to missing lock nesting notation
3 locks held by irq/124-pciehp/86:
#0: ffff8e5ac4298af8 (&ctrl->reset_lock){.+.+}-{3:3}, at: pciehp_ist+0xf3/0x180
#1: ffffffffa3b024e8 (pci_rescan_remove_lock){+.+.}-{3:3}, at: pciehp_unconfigure_device+0x31/0x110
#2: ffff8e5ac1ee2248 (&dev->mutex){....}-{3:3}, at: device_release_driver+0x1c/0x40
stack backtrace:
CPU: 4 PID: 86 Comm: irq/124-pciehp Not tainted 5.16.0-rc2+ #621
Hardware name: LENOVO 20U90SIT19/20U90SIT19, BIOS N2WET30W (1.20 ) 08/26/2021
Call Trace:
<TASK>
dump_stack_lvl+0x59/0x73
__lock_acquire.cold+0xc5/0x2c6
lock_acquire+0xb5/0x2b0
down_read+0x3e/0x50
pciehp_check_presence+0x23/0x80
pciehp_runtime_resume+0x5c/0xa0
device_for_each_child+0x45/0x70
pcie_port_device_runtime_resume+0x20/0x30
pci_pm_runtime_resume+0xa7/0xc0
__rpm_callback+0x41/0x110
rpm_callback+0x59/0x70
rpm_resume+0x512/0x7b0
__pm_runtime_resume+0x4a/0x90
__device_release_driver+0x28/0x240
device_release_driver+0x26/0x40
pci_stop_bus_device+0x68/0x90
pci_stop_bus_device+0x2c/0x90
pci_stop_and_remove_bus_device+0xe/0x20
pciehp_unconfigure_device+0x6c/0x110
pciehp_disable_slot+0x5b/0xe0
pciehp_handle_presence_or_link_change+0xc3/0x2f0
pciehp_ist+0x179/0x180
This lockdep warning is triggered because with Thunderbolt, hotplug ports
are nested. When removing multiple devices in a daisy-chain, each hotplug
port's reset_lock may be acquired recursively. It's never the same lock, so
the lockdep splat is a false positive.
Because locks at the same hierarchy level are never acquired recursively, a
per-level lockdep class is sufficient to fix the lockdep warning.
The choice to use one lockdep subclass per pcie-hotplug controller in the
path to the root-bus was made to conserve class keys because their number
is limited and the complexity grows quadratically with number of keys
according to Documentation/locking/lockdep-design.rst.
Link: https://lore.kernel.org/linux-pci/20190402021933.GA2966@mit.edu/
Link: https://lore.kernel.org/linux-pci/de684a28-9038-8fc6-27ca-3f6f2f6400d7@redhat.com/
Link: https://lore.kernel.org/r/20211217141709.379663-1-hdegoede@redhat.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=208855
Reported-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org
The functions get_max_adapter_speed() and get_bus_name() in ibmphp_core.c
are commented-out and the fields .get_max_adapter_speed and
.get_bus_name_status are removed from struct hotplug_slot_ops in
pci_hotplug.h. Remove the commented-out functions.
Link: https://lore.kernel.org/r/20211209213618.20522-1-makvihas@gmail.com
Signed-off-by: Vihas Mak <makvihas@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
The Power Fault Detected bit in the Slot Status register differs from
all other hotplug events in that it is sticky: It can only be cleared
after turning off slot power. Per PCIe r5.0, sec. 6.7.1.8:
If a power controller detects a main power fault on the hot-plug slot,
it must automatically set its internal main power fault latch [...].
The main power fault latch is cleared when software turns off power to
the hot-plug slot.
The stickiness used to cause interrupt storms and infinite loops which
were fixed in 2009 by commits 5651c48cfa ("PCI pciehp: fix power fault
interrupt storm problem") and 99f0169c17 ("PCI: pciehp: enable
software notification on empty slots").
Unfortunately in 2020 the infinite loop issue was inadvertently
reintroduced by commit 8edf5332c3 ("PCI: pciehp: Fix MSI interrupt
race"): The hardirq handler pciehp_isr() clears the PFD bit until
pciehp's power_fault_detected flag is set. That happens in the IRQ
thread pciehp_ist(), which never learns of the event because the hardirq
handler is stuck in an infinite loop. Fix by setting the
power_fault_detected flag already in the hardirq handler.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=214989
Link: https://lore.kernel.org/linux-pci/DM8PR11MB5702255A6A92F735D90A4446868B9@DM8PR11MB5702.namprd11.prod.outlook.com
Fixes: 8edf5332c3 ("PCI: pciehp: Fix MSI interrupt race")
Link: https://lore.kernel.org/r/66eaeef31d4997ceea357ad93259f290ededecfd.1637187226.git.lukas@wunner.de
Reported-by: Joseph Bao <joseph.bao@intel.com>
Tested-by: Joseph Bao <joseph.bao@intel.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: Stuart Hayes <stuart.w.hayes@gmail.com>
When config pci_ops.read() can detect failed PCI transactions, the data
returned to the CPU is PCI_ERROR_RESPONSE (~0 or 0xffffffff).
Obviously a successful PCI config read may *also* return that data if a
config register happens to contain ~0, so it doesn't definitively indicate
an error unless we know the register cannot contain ~0.
Use PCI_POSSIBLE_ERROR() to check the response we get when we read data
from hardware. This unifies PCI error response checking and makes error
checks consistent and easier to find.
Link: https://lore.kernel.org/r/b12005c0d57bb9d4c8b486724d078b7bd92f8321.1637243717.git.naveennaidu479@gmail.com
Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
When config pci_ops.read() can detect failed PCI transactions, the data
returned to the CPU is PCI_ERROR_RESPONSE (~0 or 0xffffffff).
Obviously a successful PCI config read may *also* return that data if a
config register happens to contain ~0, so it doesn't definitively indicate
an error unless we know the register cannot contain ~0.
Use PCI_POSSIBLE_ERROR() to check the response we get when we read data
from hardware. This unifies PCI error response checking and makes error
checks consistent and easier to find.
Compile tested only.
Link: https://lore.kernel.org/r/e185b052fbfd530df703a36dd31126cb870eed95.1637243717.git.naveennaidu479@gmail.com
Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Lukas Wunner <lukas@wunner.de>
This is done by adding a zpci_hot_reset_device() call which does a low
level reset of the PCI function without changing its higher level
function state. This way it can be used while the zPCI function is bound
to a driver and with DMA tables being controlled either through the
IOMMU or DMA APIs which is prohibited when using zpci_disable_device()
as that drop existing DMA translations.
As this reset, unlike a normal FLR, also calls zpci_clear_irq() we need
to implement arch_restore_msi_irqs() and make sure we re-enable IRQs for
the PCI function if they were previously disabled.
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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Merge tag 'pci-v5.16-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci
Pull pci updates from Bjorn Helgaas:
"Enumeration:
- Conserve IRQs by setting up portdrv IRQs only when there are users
(Jan Kiszka)
- Rework and simplify _OSC negotiation for control of PCIe features
(Joerg Roedel)
- Remove struct pci_dev.driver pointer since it's redundant with the
struct device.driver pointer (Uwe Kleine-König)
Resource management:
- Coalesce contiguous host bridge apertures from _CRS to accommodate
BARs that cover more than one aperture (Kai-Heng Feng)
Sysfs:
- Check CAP_SYS_ADMIN before parsing user input (Krzysztof
Wilczyński)
- Return -EINVAL consistently from "store" functions (Krzysztof
Wilczyński)
- Use sysfs_emit() in endpoint "show" functions to avoid buffer
overruns (Kunihiko Hayashi)
PCIe native device hotplug:
- Ignore Link Down/Up caused by resets during error recovery so
endpoint drivers can remain bound to the device (Lukas Wunner)
Virtualization:
- Avoid bus resets on Atheros QCA6174, where they hang the device
(Ingmar Klein)
- Work around Pericom PI7C9X2G switch packet drop erratum by using
store and forward mode instead of cut-through (Nathan Rossi)
- Avoid trying to enable AtomicOps on VFs; the PF setting applies to
all VFs (Selvin Xavier)
MSI:
- Document that /sys/bus/pci/devices/.../irq contains the legacy INTx
interrupt or the IRQ of the first MSI (not MSI-X) vector (Barry
Song)
VPD:
- Add pci_read_vpd_any() and pci_write_vpd_any() to access anywhere
in the possible VPD space; use these to simplify the cxgb3 driver
(Heiner Kallweit)
Peer-to-peer DMA:
- Add (not subtract) the bus offset when calculating DMA address
(Wang Lu)
ASPM:
- Re-enable LTR at Downstream Ports so they don't report Unsupported
Requests when reset or hot-added devices send LTR messages
(Mingchuang Qiao)
Apple PCIe controller driver:
- Add driver for Apple M1 PCIe controller (Alyssa Rosenzweig, Marc
Zyngier)
Cadence PCIe controller driver:
- Return success when probe succeeds instead of falling into error
path (Li Chen)
HiSilicon Kirin PCIe controller driver:
- Reorganize PHY logic and add support for external PHY drivers
(Mauro Carvalho Chehab)
- Support PERST# GPIOs for HiKey970 external PEX 8606 bridge (Mauro
Carvalho Chehab)
- Add Kirin 970 support (Mauro Carvalho Chehab)
- Make driver removable (Mauro Carvalho Chehab)
Intel VMD host bridge driver:
- If IOMMU supports interrupt remapping, leave VMD MSI-X remapping
enabled (Adrian Huang)
- Number each controller so we can tell them apart in
/proc/interrupts (Chunguang Xu)
- Avoid building on UML because VMD depends on x86 bare metal APIs
(Johannes Berg)
Marvell Aardvark PCIe controller driver:
- Define macros for PCI_EXP_DEVCTL_PAYLOAD_* (Pali Rohár)
- Set Max Payload Size to 512 bytes per Marvell spec (Pali Rohár)
- Downgrade PIO Response Status messages to debug level (Marek Behún)
- Preserve CRS SV (Config Request Retry Software Visibility) bit in
emulated Root Control register (Pali Rohár)
- Fix issue in configuring reference clock (Pali Rohár)
- Don't clear status bits for masked interrupts (Pali Rohár)
- Don't mask unused interrupts (Pali Rohár)
- Avoid code repetition in advk_pcie_rd_conf() (Marek Behún)
- Retry config accesses on CRS response (Pali Rohár)
- Simplify emulated Root Capabilities initialization (Pali Rohár)
- Fix several link training issues (Pali Rohár)
- Fix link-up checking via LTSSM (Pali Rohár)
- Fix reporting of Data Link Layer Link Active (Pali Rohár)
- Fix emulation of W1C bits (Marek Behún)
- Fix MSI domain .alloc() method to return zero on success (Marek
Behún)
- Read entire 16-bit MSI vector in MSI handler, not just low 8 bits
(Marek Behún)
- Clear Root Port I/O Space, Memory Space, and Bus Master Enable bits
at startup; PCI core will set those as necessary (Pali Rohár)
- When operating as a Root Port, set class code to "PCI Bridge"
instead of the default "Mass Storage Controller" (Pali Rohár)
- Add emulation for PCI_BRIDGE_CTL_BUS_RESET since aardvark doesn't
implement this per spec (Pali Rohár)
- Add emulation of option ROM BAR since aardvark doesn't implement
this per spec (Pali Rohár)
MediaTek MT7621 PCIe controller driver:
- Add MediaTek MT7621 PCIe host controller driver and DT binding
(Sergio Paracuellos)
Qualcomm PCIe controller driver:
- Add SC8180x compatible string (Bjorn Andersson)
- Add endpoint controller driver and DT binding (Manivannan
Sadhasivam)
- Restructure to use of_device_get_match_data() (Prasad Malisetty)
- Add SC7280-specific pcie_1_pipe_clk_src handling (Prasad Malisetty)
Renesas R-Car PCIe controller driver:
- Remove unnecessary includes (Geert Uytterhoeven)
Rockchip DesignWare PCIe controller driver:
- Add DT binding (Simon Xue)
Socionext UniPhier Pro5 controller driver:
- Serialize INTx masking/unmasking (Kunihiko Hayashi)
Synopsys DesignWare PCIe controller driver:
- Run dwc .host_init() method before registering MSI interrupt
handler so we can deal with pending interrupts left by bootloader
(Bjorn Andersson)
- Clean up Kconfig dependencies (Andy Shevchenko)
- Export symbols to allow more modular drivers (Luca Ceresoli)
TI DRA7xx PCIe controller driver:
- Allow host and endpoint drivers to be modules (Luca Ceresoli)
- Enable external clock if present (Luca Ceresoli)
TI J721E PCIe driver:
- Disable PHY when probe fails after initializing it (Christophe
JAILLET)
MicroSemi Switchtec management driver:
- Return error to application when command execution fails because an
out-of-band reset has cleared the device BARs, Memory Space Enable,
etc (Kelvin Cao)
- Fix MRPC error status handling issue (Kelvin Cao)
- Mask out other bits when reading of management VEP instance ID
(Kelvin Cao)
- Return EOPNOTSUPP instead of ENOTSUPP from sysfs show functions
(Kelvin Cao)
- Add check of event support (Logan Gunthorpe)
Miscellaneous:
- Remove unused pci_pool wrappers, which have been replaced by
dma_pool (Cai Huoqing)
- Use 'unsigned int' instead of bare 'unsigned' (Krzysztof
Wilczyński)
- Use kstrtobool() directly, sans strtobool() wrapper (Krzysztof
Wilczyński)
- Fix some sscanf(), sprintf() format mismatches (Krzysztof
Wilczyński)
- Update PCI subsystem information in MAINTAINERS (Krzysztof
Wilczyński)
- Correct some misspellings (Krzysztof Wilczyński)"
* tag 'pci-v5.16-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (137 commits)
PCI: Add ACS quirk for Pericom PI7C9X2G switches
PCI: apple: Configure RID to SID mapper on device addition
iommu/dart: Exclude MSI doorbell from PCIe device IOVA range
PCI: apple: Implement MSI support
PCI: apple: Add INTx and per-port interrupt support
PCI: kirin: Allow removing the driver
PCI: kirin: De-init the dwc driver
PCI: kirin: Disable clkreq during poweroff sequence
PCI: kirin: Move the power-off code to a common routine
PCI: kirin: Add power_off support for Kirin 960 PHY
PCI: kirin: Allow building it as a module
PCI: kirin: Add MODULE_* macros
PCI: kirin: Add Kirin 970 compatible
PCI: kirin: Support PERST# GPIOs for HiKey970 external PEX 8606 bridge
PCI: apple: Set up reference clocks when probing
PCI: apple: Add initial hardware bring-up
PCI: of: Allow matching of an interrupt-map local to a PCI device
of/irq: Allow matching of an interrupt-map local to an interrupt controller
irqdomain: Make of_phandle_args_to_fwspec() generally available
PCI: Do not enable AtomicOps on VFs
...
- Tidy setup-irq.c comments (Pranay Sanghai)
- Fix misspellings (Krzysztof Wilczyński)
- Fix sprintf(), sscanf() format mismatches (Krzysztof Wilczyński)
- Tidy cpqphp code formatting (Krzysztof Wilczyński)
- Remove unused pci_pool wrappers, which have been replaced by dma_pool
(Cai Huoqing)
- Remove a redundant initialization in __pci_reset_function_locked() (Colin
Ian King)
- Use 'unsigned int' instead of 'unsigned' (Krzysztof Wilczyński)
- Update PCI subsystem information in MAINTAINERS (Krzysztof Wilczyński)
- Include generic <linux/> headers instead of <asm/> for cpqphp and vmd
(Krzysztof Wilczyński)
* pci/misc:
PCI: vmd: Drop redundant includes of <asm/device.h>, <asm/msi.h>
PCI: cpqphp: Use <linux/io.h> instead of <asm/io.h>
MAINTAINERS: Update PCI subsystem information
PCI: Prefer 'unsigned int' over bare 'unsigned'
PCI: Remove redundant 'rc' initialization
PCI: Remove unused pci_pool wrappers
PCI: cpqphp: Format if-statement code block correctly
PCI: Use unsigned to match sscanf("%x") in pci_dev_str_match_path()
PCI: hv: Remove unnecessary use of %hx
PCI: Correct misspelled and remove duplicated words
PCI: Tidy comments
Use the preferred generic header file linux/io.h that already includes the
corresponding asm/io.h file.
Link: https://lore.kernel.org/r/20211013003145.1107148-2-kw@linux.com
Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jonathan Derrick <jonathan.derrick@linux.dev>
Stuart Hayes reports that an error handled by DPC at a Root Port results
in pciehp gratuitously bringing down a subordinate hotplug port:
RP -- UP -- DP -- UP -- DP (hotplug) -- EP
pciehp brings the slot down because the Link to the Endpoint goes down.
That is caused by a Hot Reset being propagated as a result of DPC.
Per PCIe Base Spec 5.0, section 6.6.1 "Conventional Reset":
For a Switch, the following must cause a hot reset to be sent on all
Downstream Ports: [...]
* The Data Link Layer of the Upstream Port reporting DL_Down status.
In Switches that support Link speeds greater than 5.0 GT/s, the
Upstream Port must direct the LTSSM of each Downstream Port to the
Hot Reset state, but not hold the LTSSMs in that state. This permits
each Downstream Port to begin Link training immediately after its
hot reset completes. This behavior is recommended for all Switches.
* Receiving a hot reset on the Upstream Port.
Once DPC recovers, pcie_do_recovery() walks down the hierarchy and
invokes pcie_portdrv_slot_reset() to restore each port's config space.
At that point, a hotplug interrupt is signaled per PCIe Base Spec r5.0,
section 6.7.3.4 "Software Notification of Hot-Plug Events":
If the Port is enabled for edge-triggered interrupt signaling using
MSI or MSI-X, an interrupt message must be sent every time the logical
AND of the following conditions transitions from FALSE to TRUE: [...]
* The Hot-Plug Interrupt Enable bit in the Slot Control register is
set to 1b.
* At least one hot-plug event status bit in the Slot Status register
and its associated enable bit in the Slot Control register are both
set to 1b.
Prevent pciehp from gratuitously bringing down the slot by clearing the
error-induced Data Link Layer State Changed event before restoring
config space. Afterwards, check whether the link has unexpectedly
failed to retrain and synthesize a DLLSC event if so.
Allow each pcie_port_service_driver (one of them being pciehp) to define
a slot_reset callback and re-use the existing pm_iter() function to
iterate over the callbacks.
Thereby, the Endpoint driver remains bound throughout error recovery and
may restore the device to working state.
Surprise removal during error recovery is detected through a Presence
Detect Changed event. The hotplug port is expected to not signal that
event as a result of a Hot Reset.
The issue isn't DPC-specific, it also occurs when an error is handled by
AER through aer_root_reset(). So while the issue was noticed only now,
it's been around since 2006 when AER support was first introduced.
[bhelgaas: drop PCI_ERROR_RECOVERY Kconfig, split pm_iter() rename to
preparatory patch]
Link: https://lore.kernel.org/linux-pci/08c046b0-c9f2-3489-eeef-7e7aca435bb9@gmail.com/
Fixes: 6c2b374d74 ("PCI-Express AER implemetation: AER core and aerdriver")
Link: https://lore.kernel.org/r/251f4edcc04c14f873ff1c967bc686169cd07d2d.1627638184.git.lukas@wunner.de
Reported-by: Stuart Hayes <stuart.w.hayes@gmail.com>
Tested-by: Stuart Hayes <stuart.w.hayes@gmail.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org # v2.6.19+: ba952824e6c1: PCI/portdrv: Report reset for frozen channel
Cc: Keith Busch <kbusch@kernel.org>
The code block related to the if-statement in cpqhp_set_irq() is
somewhat awkwardly formatted making the code hard to read.
Make it readable. No change to functionality intended.
Link: https://lore.kernel.org/r/20211013011412.1110829-1-kw@linux.com
Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Correct a number of misspelled words and remove any words that were
duplicated in the PCI tree. No change to functionality intended.
Link: https://lore.kernel.org/r/20211006233827.147328-1-kw@linux.com
Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Since commit 2a671f77ee ("s390/pci: fix use after free of zpci_dev")
the reference count of a zpci_dev is incremented between
pcibios_add_device() and pcibios_release_device() which was supposed to
prevent the zpci_dev from being freed while the common PCI code has
access to it. It was missed however that the handling of zPCI
availability events assumed that once zpci_zdev_put() was called no
later availability event would still see the device. With the previously
mentioned commit however this assumption no longer holds and we must
make sure that we only drop the initial long-lived reference the zPCI
subsystem holds exactly once.
Do so by introducing a zpci_device_reserved() function that handles when
a device is reserved. Here we make sure the zpci_dev will not be
considered for further events by removing it from the zpci_list.
This also means that the device actually stays in the
ZPCI_FN_STATE_RESERVED state between the time we know it has been
reserved and the final reference going away. We thus need to consider it
a real state instead of just a conceptual state after the removal. The
final cleanup of PCI resources, removal from zbus, and destruction of
the IOMMU stays in zpci_release_device() to make sure holders of the
reference do see valid data until the release.
Fixes: 2a671f77ee ("s390/pci: fix use after free of zpci_dev")
Cc: stable@vger.kernel.org
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
- Cache PCIe Device Capabilities register (Amey Narkhede)
- Add pcie_reset_flr() with 'probe' argument (Amey Narkhede)
- Add pdev->reset_methods[] array to track reset method ordering (Amey
Narkhede)
- Remove reset_fn field from pci_dev (Amey Narkhede)
- Add sysfs interface to query and set device reset mechanism (Amey
Narkhede)
- Add pci_set_acpi_fwnode() to set ACPI_COMPANION (Shanker Donthineni)
- Use acpi_pci_power_manageable() instead of duplicating logic (Shanker
Donthineni)
- Set ACPI fwnode early and at the same time with OF (Shanker Donthineni)
- Add support for ACPI _RST reset method (Shanker Donthineni)
- Change reset function 'probe' argument to bool (Amey Narkhede)
* pci/reset:
PCI: Change the type of probe argument in reset functions
PCI: Add support for ACPI _RST reset method
PCI: Setup ACPI fwnode early and at the same time with OF
PCI: Use acpi_pci_power_manageable()
PCI: Add pci_set_acpi_fwnode() to set ACPI_COMPANION
PCI: Allow userspace to query and set device reset mechanism
PCI: Remove reset_fn field from pci_dev
PCI: Add array to track reset method ordering
PCI: Add pcie_reset_flr() with 'probe' argument
PCI: Cache PCIe Device Capabilities register
ebda_rsrc_controller() calls iounmap(io_mem) on the error path. Its caller,
ibmphp_access_ebda(), also calls iounmap(io_mem) on good and error paths.
Remove the iounmap(io_mem) invocation from ebda_rsrc_controller().
[bhelgaas: remove item from TODO]
Link: https://lore.kernel.org/r/20210818165751.591185-1-os.vaslot@gmail.com
Signed-off-by: Vishal Aslot <os.vaslot@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Change the type of probe argument in functions which implement reset
methods from int to bool to make the context and intent clear.
Suggested-by: Alex Williamson <alex.williamson@redhat.com>
Link: https://lore.kernel.org/r/20210817180500.1253-10-ameynarkhede03@gmail.com
Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
cpci_debug is declared as a global variable in cpci_hotplug_core.c and used
in cpci_hotplug_pci.c via an "extern". Add an extern declaration in the
header file.
Resolves the following sparse warning:
drivers/pci/hotplug/cpci_hotplug_core.c:47:5: warning: symbol 'cpci_debug' was not declared. Should it be static?
Link: https://lore.kernel.org/r/20210701184306.1492003-1-kw@linux.com
Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Downstream Port Containment (PCIe r5.0, sec. 6.2.10) disables the link upon
an error and attempts to re-enable it when instructed by the DPC driver.
A slot which is both DPC- and hotplug-capable is currently powered off by
pciehp once DPC is triggered (due to the link change) and powered back up
on successful recovery. That's undesirable, the slot should remain powered
so the hotplugged device remains bound to its driver. DPC notifies the
driver of the error and of successful recovery in pcie_do_recovery() and
the driver may then restore the device to working state.
Moreover, Sinan points out that turning off slot power by pciehp may foil
recovery by DPC: Power off/on is a cold reset concurrently to DPC's warm
reset. Sathyanarayanan reports extended delays or failure in link
retraining by DPC if pciehp brings down the slot.
Fix by detecting whether a Link Down event is caused by DPC and awaiting
recovery if so. On successful recovery, ignore both the Link Down and the
subsequent Link Up event.
Afterwards, check whether the link is down to detect surprise-removal or
another DPC event immediately after DPC recovery. Ensure that the
corresponding DLLSC event is not ignored by synthesizing it and invoking
irq_wake_thread() to trigger a re-run of pciehp_ist().
The IRQ threads of the hotplug and DPC drivers, pciehp_ist() and
dpc_handler(), race against each other. If pciehp is faster than DPC, it
will wait until DPC recovery completes.
Recovery consists of two steps: The first step (waiting for link
disablement) is recognizable by pciehp through a set DPC Trigger Status
bit. The second step (waiting for link retraining) is recognizable through
a newly introduced PCI_DPC_RECOVERING flag.
If DPC is faster than pciehp, neither of the two flags will be set and
pciehp may glean the recovery status from the new PCI_DPC_RECOVERED flag.
The flag is zero if DPC didn't occur at all, hence DLLSC events are not
ignored by default.
pciehp waits up to 4 seconds before assuming that DPC recovery failed and
bringing down the slot. This timeout is not taken from the spec (it
doesn't mandate one) but based on a report from Yicong Yang that DPC may
take a bit more than 3 seconds on HiSilicon's Kunpeng platform.
The timeout is necessary because the DPC Trigger Status bit may never
clear: On Root Ports which support RP Extensions for DPC, the DPC driver
polls the DPC RP Busy bit for up to 1 second before giving up on DPC
recovery. Without the timeout, pciehp would then wait indefinitely for DPC
to complete.
This commit draws inspiration from previous attempts to synchronize DPC
with pciehp:
By Sinan Kaya, August 2018:
https://lore.kernel.org/linux-pci/20180818065126.77912-1-okaya@kernel.org/
By Ethan Zhao, October 2020:
https://lore.kernel.org/linux-pci/20201007113158.48933-1-haifeng.zhao@intel.com/
By Kuppuswamy Sathyanarayanan, March 2021:
https://lore.kernel.org/linux-pci/59cb30f5e5ac6d65427ceaadf1012b2ba8dbf66c.1615606143.git.sathyanarayanan.kuppuswamy@linux.intel.com/
Link: https://lore.kernel.org/r/0be565d97438fe2a6d57354b3aa4e8626952a00b.1619857124.git.lukas@wunner.de
Reported-by: Sinan Kaya <okaya@kernel.org>
Reported-by: Ethan Zhao <haifeng.zhao@intel.com>
Reported-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Tested-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Tested-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Keith Busch <kbusch@kernel.org>
The sysfs_emit() and sysfs_emit_at() functions were introduced to make
it less ambiguous which function is preferred when writing to the output
buffer in a device attribute's "show" callback [1].
Convert the PCI sysfs object "show" functions from sprintf(), snprintf()
and scnprintf() to sysfs_emit() and sysfs_emit_at() accordingly, as the
latter is aware of the PAGE_SIZE buffer and correctly returns the number
of bytes written into the buffer.
No functional change intended.
[1] Documentation/filesystems/sysfs.rst
Related commit: ad025f8e46 ("PCI/sysfs: Use sysfs_emit() and
sysfs_emit_at() in "show" functions").
Link: https://lore.kernel.org/r/20210603000112.703037-2-kw@linux.com
Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
- add support for system call stack randomization.
- handle stale PCI deconfiguration events.
- couple of defconfig updates.
- some fixes and cleanups.
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Merge tag 's390-5.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull more s390 updates from Heiko Carstens:
- add support for system call stack randomization
- handle stale PCI deconfiguration events
- couple of defconfig updates
- some fixes and cleanups
* tag 's390-5.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390: fix detection of vector enhancements facility 1 vs. vector packed decimal facility
s390/entry: add support for syscall stack randomization
s390/configs: change CONFIG_VIRTIO_CONSOLE to "m"
s390/cio: remove invalid condition on IO_SCH_UNREG
s390/cpumf: remove call to perf_event_update_userpage
s390/cpumf: move counter set size calculation to common place
s390/cpumf: beautify if-then-else indentation
s390/configs: enable CONFIG_PCI_IOV
s390/pci: handle stale deconfiguration events
s390/pci: rename zpci_configure_device()
Bjorn Helgaas