kernel/git/stable/linux.git/drivers/pci/hotplug, branch linux-6.15.y

PCI: pnv_php: Fix surprise plug detection and recovery

2025-08-15T10:16:57+00:00

[ Upstream commit a2a2a6fc2469524caa713036297c542746d148dc ] The existing PowerNV hotplug code did not handle surprise plug events correctly, leading to a complete failure of the hotplug system after device removal and a required reboot to detect new devices. This comes down to two issues: 1) When a device is surprise removed, often the bridge upstream port will cause a PE freeze on the PHB. If this freeze is not cleared, the MSI interrupts from the bridge hotplug notification logic will not be received by the kernel, stalling all plug events on all slots associated with the PE. 2) When a device is removed from a slot, regardless of surprise or programmatic removal, the associated PHB/PE ls left frozen. If this freeze is not cleared via a fundamental reset, skiboot is unable to clear the freeze and cannot retrain / rescan the slot. This also requires a reboot to clear the freeze and redetect the device in the slot. Issue the appropriate unfreeze and rescan commands on hotplug events, and don't oops on hotplug if pci_bus_to_OF_node() returns NULL. Signed-off-by: Timothy Pearson [bhelgaas: tidy comments] Signed-off-by: Bjorn Helgaas Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/171044224.1359864.1752615546988.JavaMail.zimbra@raptorengineeringinc.com Signed-off-by: Sasha Levin

PCI: pnv_php: Work around switches with broken presence detection

2025-08-15T10:16:56+00:00

[ Upstream commit 80f9fc2362797538ebd4fd70a1dfa838cc2c2cdb ] The Microsemi Switchtec PM8533 PFX 48xG3 [11f8:8533] PCIe switch system was observed to incorrectly assert the Presence Detect Set bit in its capabilities when tested on a Raptor Computing Systems Blackbird system, resulting in the hot insert path never attempting a rescan of the bus and any downstream devices not being re-detected. Work around this by additionally checking whether the PCIe data link is active or not when performing presence detection on downstream switches' ports, similar to the pciehp_hpc.c driver. Signed-off-by: Shawn Anastasio Signed-off-by: Timothy Pearson Signed-off-by: Bjorn Helgaas Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/505981576.1359853.1752615415117.JavaMail.zimbra@raptorengineeringinc.com Signed-off-by: Sasha Levin

PCI: pnv_php: Clean up allocated IRQs on unplug

2025-08-15T10:16:56+00:00

[ Upstream commit 4668619092554e1b95c9a5ac2941ca47ba6d548a ] When the root of a nested PCIe bridge configuration is unplugged, the pnv_php driver leaked the allocated IRQ resources for the child bridges' hotplug event notifications, resulting in a panic. Fix this by walking all child buses and deallocating all its IRQ resources before calling pci_hp_remove_devices(). Also modify the lifetime of the workqueue at struct pnv_php_slot::wq so that it is only destroyed in pnv_php_free_slot(), instead of pnv_php_disable_irq(). This is required since pnv_php_disable_irq() will now be called by workers triggered by hot unplug interrupts, so the workqueue needs to stay allocated. The abridged kernel panic that occurs without this patch is as follows: WARNING: CPU: 0 PID: 687 at kernel/irq/msi.c:292 msi_device_data_release+0x6c/0x9c CPU: 0 UID: 0 PID: 687 Comm: bash Not tainted 6.14.0-rc5+ #2 Call Trace: msi_device_data_release+0x34/0x9c (unreliable) release_nodes+0x64/0x13c devres_release_all+0xc0/0x140 device_del+0x2d4/0x46c pci_destroy_dev+0x5c/0x194 pci_hp_remove_devices+0x90/0x128 pci_hp_remove_devices+0x44/0x128 pnv_php_disable_slot+0x54/0xd4 power_write_file+0xf8/0x18c pci_slot_attr_store+0x40/0x5c sysfs_kf_write+0x64/0x78 kernfs_fop_write_iter+0x1b0/0x290 vfs_write+0x3bc/0x50c ksys_write+0x84/0x140 system_call_exception+0x124/0x230 system_call_vectored_common+0x15c/0x2ec Signed-off-by: Shawn Anastasio Signed-off-by: Timothy Pearson [bhelgaas: tidy comments] Signed-off-by: Bjorn Helgaas Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/2013845045.1359852.1752615367790.JavaMail.zimbra@raptorengineeringinc.com Signed-off-by: Sasha Levin

PCI: pciehp: Ignore belated Presence Detect Changed caused by DPC

2025-06-27T10:13:43+00:00

[ Upstream commit bbf10cd686835d5a4b8566dc73a3b00b4cd7932a ] Commit c3be50f7547c ("PCI: pciehp: Ignore Presence Detect Changed caused by DPC") sought to ignore Presence Detect Changed events occurring as a side effect of Downstream Port Containment. The commit awaits recovery from DPC and then clears events which occurred in the meantime. However if the first event seen after DPC is Data Link Layer State Changed, only that event is cleared and not Presence Detect Changed. The object of the commit is thus defeated. That's because pciehp_ist() computes the events to clear based on the local "events" variable instead of "ctrl->pending_events". The former contains the events that had occurred when pciehp_ist() was entered, whereas the latter also contains events that have accumulated while awaiting DPC recovery. In practice, the order of PDC and DLLSC events is arbitrary and the delay in-between can be several milliseconds. So change the logic to always clear PDC events, even if they come after an initial DLLSC event. Fixes: c3be50f7547c ("PCI: pciehp: Ignore Presence Detect Changed caused by DPC") Reported-by: Lương Việt Hoàng Reported-by: Joel Mathew Thomas Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219765#c165 Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Tested-by: Lương Việt Hoàng Tested-by: Joel Mathew Thomas Link: https://patch.msgid.link/d9c4286a16253af7e93eaf12e076e3ef3546367a.1750257164.git.lukas@wunner.de Signed-off-by: Sasha Levin

s390/pci: Prevent self deletion in disable_slot()

2025-06-27T10:12:56+00:00

commit 47c397844869ad0e6738afb5879c7492f4691122 upstream. As disable_slot() takes a struct zpci_dev from the Configured to the Standby state. In Standby there is still a hotplug slot so this is not usually a case of sysfs self deletion. This is important because self deletion gets very hairy in terms of locking (see for example recover_store() in arch/s390/pci/pci_sysfs.c). Because the pci_dev_put() is not within the critical section of the zdev->state_lock however, disable_slot() can turn into a case of self deletion if zPCI device event handling slips between the mutex_unlock() and the pci_dev_put(). If the latter is the last put and zpci_release_device() is called this then tries to remove the hotplug slot via zpci_exit_slot() which will try to remove the hotplug slot directory the disable_slot() is part of i.e. self deletion. Prevent this by widening the zdev->state_lock critical section to include the pci_dev_put() which is then guaranteed to happen with the struct zpci_dev still in Standby state ensuring it will not lead to a zpci_release_device() call as at least the zPCI event handling code still holds a reference. Cc: stable@vger.kernel.org Fixes: a46044a92add ("s390/pci: fix zpci_zdev_put() on reserve") Reviewed-by: Gerd Bayer Tested-by: Gerd Bayer Signed-off-by: Niklas Schnelle Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman

PCI: pciehp: Ignore Link Down/Up caused by Secondary Bus Reset

2025-06-19T13:40:26+00:00

[ Upstream commit 2af781a9edc4ef5f6684c0710cc3542d9be48b31 ] When a Secondary Bus Reset is issued at a hotplug port, it causes a Data Link Layer State Changed event as a side effect. On hotplug ports using in-band presence detect, it additionally causes a Presence Detect Changed event. These spurious events should not result in teardown and re-enumeration of the device in the slot. Hence commit 2e35afaefe64 ("PCI: pciehp: Add reset_slot() method") masked the Presence Detect Changed Enable bit in the Slot Control register during a Secondary Bus Reset. Commit 06a8d89af551 ("PCI: pciehp: Disable link notification across slot reset") additionally masked the Data Link Layer State Changed Enable bit. However masking those bits only disables interrupt generation (PCIe r6.2 sec 6.7.3.1). The events are still visible in the Slot Status register and picked up by the IRQ handler if it runs during a Secondary Bus Reset. This can happen if the interrupt is shared or if an unmasked hotplug event occurs, e.g. Attention Button Pressed or Power Fault Detected. The likelihood of this happening used to be small, so it wasn't much of a problem in practice. That has changed with the recent introduction of bandwidth control in v6.13-rc1 with commit 665745f27487 ("PCI/bwctrl: Re-add BW notification portdrv as PCIe BW controller"): Bandwidth control shares the interrupt with PCIe hotplug. A Secondary Bus Reset causes a Link Bandwidth Notification, so the hotplug IRQ handler runs, picks up the masked events and tears down the device in the slot. As a result, Joel reports VFIO passthrough failure of a GPU, which Ilpo root-caused to the incorrect handling of masked hotplug events. Clearly, a more reliable way is needed to ignore spurious hotplug events. For Downstream Port Containment, a new ignore mechanism was introduced by commit a97396c6eb13 ("PCI: pciehp: Ignore Link Down/Up caused by DPC"). It has been working reliably for the past four years. Adapt it for Secondary Bus Resets. Introduce two helpers to annotate code sections which cause spurious link changes: pci_hp_ignore_link_change() and pci_hp_unignore_link_change() Use those helpers in lieu of masking interrupts in the Slot Control register. Introduce a helper to check whether such a code section is executing concurrently and if so, await it: pci_hp_spurious_link_change() Invoke the helper in the hotplug IRQ thread pciehp_ist(). Re-use the IRQ thread's existing code which ignores DPC-induced link changes unless the link is unexpectedly down after reset recovery or the device was replaced during the bus reset. That code block in pciehp_ist() was previously only executed if a Data Link Layer State Changed event has occurred. Additionally execute it for Presence Detect Changed events. That's necessary for compatibility with PCIe r1.0 hotplug ports because Data Link Layer State Changed didn't exist before PCIe r1.1. DPC was added with PCIe r3.1 and thus DPC-capable hotplug ports always support Data Link Layer State Changed events. But the same cannot be assumed for Secondary Bus Reset, which already existed in PCIe r1.0. Secondary Bus Reset is only one of many causes of spurious link changes. Others include runtime suspend to D3cold, firmware updates or FPGA reconfiguration. The new pci_hp_{,un}ignore_link_change() helpers may be used by all kinds of drivers to annotate such code sections, hence their declarations are publicly visible in . A case in point is the Mellanox Ethernet driver which disables a firmware reset feature if the Ethernet card is attached to a hotplug port, see commit 3d7a3f2612d7 ("net/mlx5: Nack sync reset request when HotPlug is enabled"). Going forward, PCIe hotplug will be able to cope gracefully with all such use cases once the code sections are properly annotated. The new helpers internally use two bits in struct pci_dev's priv_flags as well as a wait_queue. This mirrors what was done for DPC by commit a97396c6eb13 ("PCI: pciehp: Ignore Link Down/Up caused by DPC"). That may be insufficient if spurious link changes are caused by multiple sources simultaneously. An example might be a Secondary Bus Reset issued by AER during FPGA reconfiguration. If this turns out to happen in real life, support for it can easily be added by replacing the PCI_LINK_CHANGING flag with an atomic_t counter incremented by pci_hp_ignore_link_change() and decremented by pci_hp_unignore_link_change(). Instead of awaiting a zero PCI_LINK_CHANGING flag, the pci_hp_spurious_link_change() helper would then simply await a zero counter. Fixes: 665745f27487 ("PCI/bwctrl: Re-add BW notification portdrv as PCIe BW controller") Reported-by: Joel Mathew Thomas Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219765 Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Tested-by: Joel Mathew Thomas Reviewed-by: Kuppuswamy Sathyanarayanan Reviewed-by: Ilpo Järvinen Link: https://patch.msgid.link/d04deaf49d634a2edf42bf3c06ed81b4ca54d17b.1744298239.git.lukas@wunner.de Signed-off-by: Sasha Levin

PCI: pciehp: Ignore Presence Detect Changed caused by DPC

2025-06-19T13:40:26+00:00

[ Upstream commit c3be50f7547ccb533284b22f74baf37d3379843e ] Commit a97396c6eb13 ("PCI: pciehp: Ignore Link Down/Up caused by DPC") amended PCIe hotplug to not bring down the slot upon Data Link Layer State Changed events caused by Downstream Port Containment. However Keith reports off-list that if the slot uses in-band presence detect (i.e. Presence Detect State is derived from Data Link Layer Link Active), DPC also causes a spurious Presence Detect Changed event. This needs to be ignored as well. Unfortunately there's no register indicating that in-band presence detect is used. PCIe r5.0 sec 7.5.3.10 introduced the In-Band PD Disable bit in the Slot Control Register. The PCIe hotplug driver sets this bit on ports supporting it. But older ports may still use in-band presence detect. If in-band presence detect can be disabled, Presence Detect Changed events occurring during DPC must not be ignored because they signal device replacement. On all other ports, device replacement cannot be detected reliably because the Presence Detect Changed event could be a side effect of DPC. On those (older) ports, perform a best-effort device replacement check by comparing the Vendor ID, Device ID and other data in Config Space with the values cached in struct pci_dev. Use the existing helper pciehp_device_replaced() to accomplish this. It is currently #ifdef'ed to CONFIG_PM_SLEEP in pciehp_core.c, so move it to pciehp_hpc.c where most other functions accessing config space reside. Reported-by: Keith Busch Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Reviewed-by: Kuppuswamy Sathyanarayanan Reviewed-by: Ilpo Järvinen Link: https://patch.msgid.link/fa264ff71952915c4e35a53c89eb0cde8455a5c5.1744298239.git.lukas@wunner.de Stable-dep-of: 2af781a9edc4 ("PCI: pciehp: Ignore Link Down/Up caused by Secondary Bus Reset") Signed-off-by: Sasha Levin

s390/pci: Fix duplicate pci_dev_put() in disable_slot() when PF has child VFs

2025-05-07T11:35:05+00:00

With commit bcb5d6c76903 ("s390/pci: introduce lock to synchronize state of zpci_dev's") the code to ignore power off of a PF that has child VFs was changed from a direct return to a goto to the unlock and pci_dev_put() section. The change however left the existing pci_dev_put() untouched resulting in a doubple put. This can subsequently cause a use after free if the struct pci_dev is released in an unexpected state. Fix this by removing the extra pci_dev_put(). Cc: stable@vger.kernel.org Fixes: bcb5d6c76903 ("s390/pci: introduce lock to synchronize state of zpci_dev's") Signed-off-by: Niklas Schnelle Reviewed-by: Gerd Bayer Signed-off-by: Heiko Carstens

treewide: Switch/rename to timer_delete[_sync]()

2025-04-05T08:30:12+00:00

timer_delete[_sync]() replaces del_timer[_sync](). Convert the whole tree over and remove the historical wrapper inlines. Conversion was done with coccinelle plus manual fixups where necessary. Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar

Merge branch 'pci/misc'

2025-03-27T18:15:05+00:00

- Remove unused tools 'pci' build target left over after moving tests to tools/testing/selftests/pci_endpoint (Jianfeng Liu) - Fix typos and whitespace errors (Bjorn Helgaas) * pci/misc: PCI: Fix typos tools/Makefile: Remove pci target # Conflicts: # drivers/pci/endpoint/functions/pci-epf-test.c