linux-stable.git/drivers/pci/hotplug, branch linux-5.4.y

PCI: pnv_php: Work around switches with broken presence detection

2025-08-28T14:21:29+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/hotplug/pnv-php: Wrap warnings in macro

2025-08-28T14:21:22+00:00

[ Upstream commit 748ac391ab9acd8d7f3c93cbf3e63c773c0b2638 ]

An opencapi slot doesn't have an associated bridge device. It's not
needed for operation, but any warning is displayed through pci_warn()
which uses the pci_dev struct of the assocated bridge device. So wrap
those warning so that a different trace mechanism can be used if it's
an opencapi slot.

Reviewed-by: Alastair D'Silva 
Reviewed-by: Andrew Donnellan 
Signed-off-by: Frederic Barrat 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20191121134918.7155-11-fbarrat@linux.ibm.com
Stable-dep-of: 466861909255 ("PCI: pnv_php: Clean up allocated IRQs on unplug")
Signed-off-by: Sasha Levin

pci/hotplug/pnv-php: Improve error msg on power state change failure

2025-08-28T14:21:22+00:00

[ Upstream commit 323c2a26ff43500a96799250330fab68903d776f ]

When changing the slot state, if opal hits an error and tells as such
in the asynchronous reply, the warning "Wrong msg" is logged, which is
rather confusing. Instead we can reuse the better message which is
already used when we couldn't submit the asynchronous opal request
initially.

Reviewed-by: Alastair D'Silva 
Reviewed-by: Andrew Donnellan 
Signed-off-by: Frederic Barrat 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20191121134918.7155-8-fbarrat@linux.ibm.com
Stable-dep-of: 466861909255 ("PCI: pnv_php: Clean up allocated IRQs on unplug")
Signed-off-by: Sasha Levin

PCI: pciehp: Don't enable HPIE when resuming in poll mode

2025-04-10T12:29:40+00:00

[ Upstream commit 527664f738afb6f2c58022cd35e63801e5dc7aec ]

PCIe hotplug can operate in poll mode without interrupt handlers using a
polling kthread only.  eb34da60edee ("PCI: pciehp: Disable hotplug
interrupt during suspend") failed to consider that and enables HPIE
(Hot-Plug Interrupt Enable) unconditionally when resuming the Port.

Only set HPIE if non-poll mode is in use. This makes
pcie_enable_interrupt() match how pcie_enable_notification() already
handles HPIE.

Link: https://lore.kernel.org/r/20250321162114.3939-1-ilpo.jarvinen@linux.intel.com
Fixes: eb34da60edee ("PCI: pciehp: Disable hotplug interrupt during suspend")
Signed-off-by: Ilpo Järvinen 
Signed-off-by: Bjorn Helgaas 
Reviewed-by: Lukas Wunner 
Signed-off-by: Sasha Levin

PCI: cpqphp: Fix PCIBIOS_* return value confusion

2024-12-14T18:44:31+00:00

[ Upstream commit e2226dbc4a4919d9c8bd9293299b532090bdf020 ]

Code in and related to PCI_RefinedAccessConfig() has three types of return
type confusion:

 - PCI_RefinedAccessConfig() tests pci_bus_read_config_dword() return value
   against -1.

 - PCI_RefinedAccessConfig() returns both -1 and PCIBIOS_* return codes.

 - Callers of PCI_RefinedAccessConfig() only test for -1.

Make PCI_RefinedAccessConfig() return PCIBIOS_* codes consistently and
adapt callers accordingly.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Link: https://lore.kernel.org/r/20241022091140.3504-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Ilpo Järvinen 
Signed-off-by: Bjorn Helgaas 
Signed-off-by: Sasha Levin

PCI: cpqphp: Use PCI_POSSIBLE_ERROR() to check config reads

2024-12-14T18:44:31+00:00

[ Upstream commit a18a025c2fb5fbf2d1d0606ea0d7441ac90e9c39 ]

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 
Signed-off-by: Bjorn Helgaas 
Stable-dep-of: e2226dbc4a49 ("PCI: cpqphp: Fix PCIBIOS_* return value confusion")
Signed-off-by: Sasha Levin

pci/hotplug/pnv_php: Fix hotplug driver crash on Powernv

2024-09-12T09:03:54+00:00

[ Upstream commit 335e35b748527f0c06ded9eebb65387f60647fda ]

The hotplug driver for powerpc (pci/hotplug/pnv_php.c) causes a kernel
crash when we try to hot-unplug/disable the PCIe switch/bridge from
the PHB.

The crash occurs because although the MSI data structure has been
released during disable/hot-unplug path and it has been assigned
with NULL, still during unregistration the code was again trying to
explicitly disable the MSI which causes the NULL pointer dereference and
kernel crash.

The patch fixes the check during unregistration path to prevent invoking
pci_disable_msi/msix() since its data structure is already freed.

Reported-by: Timothy Pearson 
Closes: https://lore.kernel.org/all/1981605666.2142272.1703742465927.JavaMail.zimbra@raptorengineeringinc.com/
Acked-by: Bjorn Helgaas 
Tested-by: Shawn Anastasio 
Signed-off-by: Krishna Kumar 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20240701074513.94873-2-krishnak@linux.ibm.com
Signed-off-by: Sasha Levin

Revert "PCI: acpiphp: Reassign resources on bridge if necessary"

2023-12-20T14:41:19+00:00

commit 5df12742b7e3aae2594a30a9d14d5d6e9e7699f4 upstream.

This reverts commit 40613da52b13fb21c5566f10b287e0ca8c12c4e9 and the
subsequent fix to it:

  cc22522fd55e ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus")

40613da52b13 fixed a problem where hot-adding a device with large BARs
failed if the bridge windows programmed by firmware were not large enough.

cc22522fd55e ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources()
only for non-root bus") fixed a problem with 40613da52b13: an ACPI hot-add
of a device on a PCI root bus (common in the virt world) or firmware
sending ACPI Bus Check to non-existent Root Ports (e.g., on Dell Inspiron
7352/0W6WV0) caused a NULL pointer dereference and suspend/resume hangs.

Unfortunately the combination of 40613da52b13 and cc22522fd55e caused other
problems:

  - Fiona reported that hot-add of SCSI disks in QEMU virtual machine fails
    sometimes.

  - Dongli reported a similar problem with hot-add of SCSI disks.

  - Jonathan reported a console freeze during boot on bare metal due to an
    error in radeon GPU initialization.

Revert both patches to avoid adding these problems.  This means we will
again see the problems with hot-adding devices with large BARs and the NULL
pointer dereferences and suspend/resume issues that 40613da52b13 and
cc22522fd55e were intended to fix.

Fixes: 40613da52b13 ("PCI: acpiphp: Reassign resources on bridge if necessary")
Fixes: cc22522fd55e ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus")
Reported-by: Fiona Ebner 
Closes: https://lore.kernel.org/r/9eb669c0-d8f2-431d-a700-6da13053ae54@proxmox.com
Reported-by: Dongli Zhang 
Closes: https://lore.kernel.org/r/3c4a446a-b167-11b8-f36f-d3c1b49b42e9@oracle.com
Reported-by: Jonathan Woithe 
Closes: https://lore.kernel.org/r/ZXpaNCLiDM+Kv38H@marvin.atrad.com.au
Signed-off-by: Bjorn Helgaas 
Acked-by: Michael S. Tsirkin 
Acked-by: Igor Mammedov 
Cc: 
Signed-off-by: Greg Kroah-Hartman

PCI: pciehp: Use RMW accessors for changing LNKCTL

2023-09-23T08:59:47+00:00

[ Upstream commit 5f75f96c61039151c193775d776fde42477eace1 ]

As hotplug is not the only driver touching LNKCTL, use the RMW capability
accessor which handles concurrent changes correctly.

Suggested-by: Lukas Wunner 
Fixes: 7f822999e12a ("PCI: pciehp: Add Disable/enable link functions")
Link: https://lore.kernel.org/r/20230717120503.15276-4-ilpo.jarvinen@linux.intel.com
Signed-off-by: Ilpo Järvinen 
Signed-off-by: Bjorn Helgaas 
Acked-by: "Rafael J. Wysocki" 
Signed-off-by: Sasha Levin

PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus

2023-08-30T14:27:26+00:00

commit cc22522fd55e257c86d340ae9aedc122e705a435 upstream.

40613da52b13 ("PCI: acpiphp: Reassign resources on bridge if necessary")
changed acpiphp hotplug to use pci_assign_unassigned_bridge_resources()
which depends on bridge being available, however enable_slot() can be
called without bridge associated:

  1. Legitimate case of hotplug on root bus (widely used in virt world)

  2. A (misbehaving) firmware, that sends ACPI Bus Check notifications to
     non existing root ports (Dell Inspiron 7352/0W6WV0), which end up at
     enable_slot(..., bridge = 0) where bus has no bridge assigned to it.
     acpihp doesn't know that it's a bridge, and bus specific 'PCI
     subsystem' can't augment ACPI context with bridge information since
     the PCI device to get this data from is/was not available.

Issue is easy to reproduce with QEMU's 'pc' machine, which supports PCI
hotplug on hostbridge slots. To reproduce, boot kernel at commit
40613da52b13 in VM started with following CLI (assuming guest root fs is
installed on sda1 partition):

  # qemu-system-x86_64 -M pc -m 1G -enable-kvm -cpu host \
        -monitor stdio -serial file:serial.log           \
        -kernel arch/x86/boot/bzImage                    \
        -append "root=/dev/sda1 console=ttyS0"           \
        guest_disk.img

Once guest OS is fully booted at qemu prompt:

  (qemu) device_add e1000

(check serial.log) it will cause NULL pointer dereference at:

  void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge)
  {
    struct pci_bus *parent = bridge->subordinate;

  BUG: kernel NULL pointer dereference, address: 0000000000000018

   ? pci_assign_unassigned_bridge_resources+0x1f/0x260
   enable_slot+0x21f/0x3e0
   acpiphp_hotplug_notify+0x13d/0x260
   acpi_device_hotplug+0xbc/0x540
   acpi_hotplug_work_fn+0x15/0x20
   process_one_work+0x1f7/0x370
   worker_thread+0x45/0x3b0

The issue was discovered on Dell Inspiron 7352/0W6WV0 laptop with following
sequence:

  1. Suspend to RAM
  2. Wake up with the same backtrace being observed:
  3. 2nd suspend to RAM attempt makes laptop freeze

Fix it by using __pci_bus_assign_resources() instead of
pci_assign_unassigned_bridge_resources() as we used to do, but only in case
when bus doesn't have a bridge associated (to cover for the case of ACPI
event on hostbridge or non existing root port).

That lets us keep hotplug on root bus working like it used to and at the
same time keeps resource reassignment usable on root ports (and other 1st
level bridges) that was fixed by 40613da52b13.

Fixes: 40613da52b13 ("PCI: acpiphp: Reassign resources on bridge if necessary")
Link: https://lore.kernel.org/r/20230726123518.2361181-2-imammedo@redhat.com
Reported-by: Woody Suwalski 
Tested-by: Woody Suwalski 
Tested-by: Michal Koutný 
Link: https://lore.kernel.org/r/11fc981c-af49-ce64-6b43-3e282728bd1a@gmail.com
Signed-off-by: Igor Mammedov 
Signed-off-by: Bjorn Helgaas 
Acked-by: Rafael J. Wysocki 
Acked-by: Michael S. Tsirkin 
Signed-off-by: Greg Kroah-Hartman