kernel/linux.git/drivers/pci/bus.c, branch v6.6.131

PCI/ASPM: Fix deadlock when enabling ASPM

2024-04-27T15:11:44+00:00

commit 1e560864159d002b453da42bd2c13a1805515a20 upstream. A last minute revert in 6.7-final introduced a potential deadlock when enabling ASPM during probe of Qualcomm PCIe controllers as reported by lockdep: ============================================ WARNING: possible recursive locking detected 6.7.0 #40 Not tainted -------------------------------------------- kworker/u16:5/90 is trying to acquire lock: ffffacfa78ced000 (pci_bus_sem){++++}-{3:3}, at: pcie_aspm_pm_state_change+0x58/0xdc but task is already holding lock: ffffacfa78ced000 (pci_bus_sem){++++}-{3:3}, at: pci_walk_bus+0x34/0xbc other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(pci_bus_sem); lock(pci_bus_sem); *** DEADLOCK *** Call trace: print_deadlock_bug+0x25c/0x348 __lock_acquire+0x10a4/0x2064 lock_acquire+0x1e8/0x318 down_read+0x60/0x184 pcie_aspm_pm_state_change+0x58/0xdc pci_set_full_power_state+0xa8/0x114 pci_set_power_state+0xc4/0x120 qcom_pcie_enable_aspm+0x1c/0x3c [pcie_qcom] pci_walk_bus+0x64/0xbc qcom_pcie_host_post_init_2_7_0+0x28/0x34 [pcie_qcom] The deadlock can easily be reproduced on machines like the Lenovo ThinkPad X13s by adding a delay to increase the race window during asynchronous probe where another thread can take a write lock. Add a new pci_set_power_state_locked() and associated helper functions that can be called with the PCI bus semaphore held to avoid taking the read lock twice. Link: https://lore.kernel.org/r/ZZu0qx2cmn7IwTyQ@hovoldconsulting.com Link: https://lore.kernel.org/r/20240130100243.11011-1-johan+linaro@kernel.org Fixes: f93e71aea6c6 ("Revert "PCI/ASPM: Remove pcie_aspm_pm_state_change()"") Signed-off-by: Johan Hovold Signed-off-by: Bjorn Helgaas Cc: # 6.7 [bhelgaas: backported to v6.6.y, which contains 8cc22ba3f77c ("Revert "PCI/ASPM: Remove pcie_aspm_pm_state_change()""), a backport of f93e71aea6c6. This omits the drivers/pci/controller/dwc/pcie-qcom.c hunk that updates qcom_pcie_enable_aspm(), which was added by 9f4f3dfad8cf ("PCI: qcom: Enable ASPM for platforms supporting 1.9.0 ops"), which is not present in v6.6.28.] Signed-off-by: Bjorn Helgaas Signed-off-by: Greg Kroah-Hartman

Merge tag 'devicetree-for-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux

2023-08-30T23:59:03+00:00

Pull devicetree updates from Rob Herring: "DT core: - Add support for generating DT nodes for PCI devices. This is the groundwork for applying overlays to PCI devices containing non-discoverable downstream devices. - DT unittest additions to check reverted changesets, to test for refcount issues, and to test unresolved symbols. Also, various clean-ups of the unittest along the way. - Refactor node and property manipulation functions to better share code with old API and changeset API - Refactor changeset print functions to a common implementation - Move some platform_device specific functions into of_platform.c Bindings: - Treewide fixing of typos - Treewide clean-up of SPDX tags to use 'OR' consistently - Last chunk of dropping unnecessary quotes. With that, the check for unnecessary quotes is enabled in yamllint. - Convert ftgmac100, zynqmp-genpd, pps-gpio, syna,rmi4, and qcom,ssbi bindings to DT schema format - Add Allwinner V3s xHCI USB, Saef SF-TC154B display, QCom SM8450 Inline Crypto Engine, QCom SM6115 UFS, QCom SDM670 PDC interrupt controller, Arm 2022 Cortex cores, and QCom IPQ9574 Crypto bindings - Fixes for Rockchip DWC PCI binding - Ensure all properties are evaluated on USB connector schema - Fix dt-check-compatible script to find of_device_id instances with compiler annotations" * tag 'devicetree-for-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (64 commits) dt-bindings: usb: Add V3s compatible string for OHCI dt-bindings: usb: Add V3s compatible string for EHCI dt-bindings: display: panel: mipi-dbi-spi: add Saef SF-TC154B dt-bindings: vendor-prefixes: document Saef Technology dt-bindings: thermal: lmh: update maintainer address of: unittest: Fix of_unittest_pci_node() kconfig dependencies dt-bindings: crypto: ice: Document sm8450 inline crypto engine dt-bindings: ufs: qcom: Add ICE to sm8450 example dt-bindings: ufs: qcom: Add sm6115 binding dt-bindings: ufs: qcom: Add reg-names property for ICE dt-bindings: yamllint: Enable quoted string check dt-bindings: Drop remaining unneeded quotes of: unittest-data: Fix whitespace - angular brackets of: unittest-data: Fix whitespace - indentation of: unittest-data: Fix whitespace - blank lines of: unittest-data: Convert remaining overlay DTS files to sugar syntax of: overlay: unittest: Add test for unresolved symbol of: unittest: Add separators to of_unittest_overlay_high_level() of: unittest: Cleanup partially-applied overlays of: unittest: Merge of_unittest_apply{,_revert}_overlay_check() ...

PCI: Create device tree node for bridge

2023-08-22T19:56:09+00:00

The PCI endpoint device such as Xilinx Alveo PCI card maps the register spaces from multiple hardware peripherals to its PCI BAR. Normally, the PCI core discovers devices and BARs using the PCI enumeration process. There is no infrastructure to discover the hardware peripherals that are present in a PCI device, and which can be accessed through the PCI BARs. Apparently, the device tree framework requires a device tree node for the PCI device. Thus, it can generate the device tree nodes for hardware peripherals underneath. Because PCI is self discoverable bus, there might not be a device tree node created for PCI devices. Furthermore, if the PCI device is hot pluggable, when it is plugged in, the device tree nodes for its parent bridges are required. Add support to generate device tree node for PCI bridges. Add an of_pci_make_dev_node() interface that can be used to create device tree node for PCI devices. Add a PCI_DYNAMIC_OF_NODES config option. When the option is turned on, the kernel will generate device tree nodes for PCI bridges unconditionally. Initially, add the basic properties for the dynamically generated device tree nodes which include #address-cells, #size-cells, device_type, compatible, ranges, reg. Acked-by: Bjorn Helgaas Signed-off-by: Lizhi Hou Link: https://lore.kernel.org/r/1692120000-46900-3-git-send-email-lizhi.hou@amd.com Signed-off-by: Rob Herring

PCI: move OF status = "disabled" detection to dev->match_driver

2023-08-09T08:18:30+00:00

The blamed commit has broken probing on arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi when &enetc_port0 (PCI function 0) has status = "disabled". Background: pci_scan_slot() has logic to say that if the function 0 of a device is absent, the entire device is absent and we can skip the other functions entirely. Traditionally, this has meant that pci_bus_read_dev_vendor_id() returns an error code for that function. However, since the blamed commit, there is an extra confounding condition: function 0 of the device exists and has a valid vendor id, but it is disabled in the device tree. In that case, pci_scan_slot() would incorrectly skip the entire device instead of just that function. In the case of NXP LS1028A, status = "disabled" does not mean that the PCI function's config space is not available for reading. It is, but the Ethernet port is just not functionally useful with a particular SerDes protocol configuration (0x9999) due to pinmuxing constraints of the Soc. So, pci_scan_slot() skips all other functions on the ENETC ECAM (enetc_port1, enetc_port2, enetc_mdio_pf3 etc) when just enetc_port0 had to not be probed. There is an additional regression introduced by the change, caused by its fundamental premise. The enetc driver needs to run code for all PCI functions, regardless of whether they're enabled or not in the device tree. That is no longer possible if the driver's probe function is no longer called. But Rob recommends that we move the of_device_is_available() detection to dev->match_driver, and this makes the PCI fixups still run on all functions, while just probing drivers for those functions that are enabled. So, a separate change in the enetc driver will have to move the workarounds to a PCI fixup. Fixes: 6fffbc7ae137 ("PCI: Honor firmware's device disabled status") Link: https://lore.kernel.org/netdev/CAL_JsqLsVYiPLx2kcHkDQ4t=hQVCR7NHziDwi9cCFUFhx48Qow@mail.gmail.com/ Suggested-by: Rob Herring Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller

Merge tag 'pci-v6.4-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci

2023-04-27T17:45:30+00:00

Pull pci updates from Bjorn Helgaas: "Resource management: - Add pci_dev_for_each_resource() and pci_bus_for_each_resource() iterators PCIe native device hotplug: - Fix AB-BA deadlock between reset_lock and device_lock Power management: - Wait longer for devices to become ready after resume (as we do for reset) to accommodate Intel Titan Ridge xHCI devices - Extend D3hot delay for NVIDIA HDA controllers to avoid unrecoverable devices after a bus reset Error handling: - Clear PCIe Device Status after EDR since generic error recovery now only clears it when AER is native ASPM: - Work around Chromebook firmware defect that clobbers Capability list (including ASPM L1 PM Substates Cap) when returning from D3cold to D0 Freescale i.MX6 PCIe controller driver: - Install imprecise external abort handler only when DT indicates PCIe support Freescale Layerscape PCIe controller driver: - Add ls1028a endpoint mode support Qualcomm PCIe controller driver: - Add SM8550 DT binding and driver support - Add SDX55 DT binding and driver support - Use bulk APIs for clocks of IP 1.0.0, 2.3.2, 2.3.3 - Use bulk APIs for reset of IP 2.1.0, 2.3.3, 2.4.0 - Add DT "mhi" register region for supported SoCs - Expose link transition counts via debugfs to help debug low power issues - Support system suspend and resume; reduce interconnect bandwidth and turn off clock and PHY if there are no active devices - Enable async probe by default to reduce boot time Miscellaneous: - Sort controller Kconfig entries by vendor" * tag 'pci-v6.4-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci: (56 commits) PCI: xilinx: Drop obsolete dependency on COMPILE_TEST PCI: mobiveil: Sort Kconfig entries by vendor PCI: dwc: Sort Kconfig entries by vendor PCI: Sort controller Kconfig entries by vendor PCI: Use consistent controller Kconfig menu entry language PCI: xilinx-nwl: Add 'Xilinx' to Kconfig prompt PCI: hv: Add 'Microsoft' to Kconfig prompt PCI: meson: Add 'Amlogic' to Kconfig prompt PCI: Use of_property_present() for testing DT property presence PCI/PM: Extend D3hot delay for NVIDIA HDA controllers dt-bindings: PCI: qcom: Document msi-map and msi-map-mask properties PCI: qcom: Add SM8550 PCIe support dt-bindings: PCI: qcom: Add SM8550 compatible PCI: qcom: Add support for SDX55 SoC dt-bindings: PCI: qcom-ep: Fix the unit address used in example dt-bindings: PCI: qcom: Add SDX55 SoC dt-bindings: PCI: qcom: Update maintainers entry PCI: qcom: Enable async probe by default PCI: qcom: Add support for system suspend and resume PCI/PM: Drop pci_bridge_wait_for_secondary_bus() timeout parameter ...

PCI: Make pci_bus_for_each_resource() index optional

2023-04-05T20:10:09+00:00

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 Signed-off-by: Bjorn Helgaas Reviewed-by: Krzysztof Wilczyński Reviewed-by: Philippe Mathieu-Daudé

PCI: s390: Fix use-after-free of PCI resources with per-function hotplug

2023-03-13T08:15:11+00:00

On s390 PCI functions may be hotplugged individually even when they belong to a multi-function device. In particular on an SR-IOV device VFs may be removed and later re-added. In commit a50297cf8235 ("s390/pci: separate zbus creation from scanning") it was missed however that struct pci_bus and struct zpci_bus's resource list retained a reference to the PCI functions MMIO resources even though those resources are released and freed on hot-unplug. These stale resources may subsequently be claimed when the PCI function re-appears resulting in use-after-free. One idea of fixing this use-after-free in s390 specific code that was investigated was to simply keep resources around from the moment a PCI function first appeared until the whole virtual PCI bus created for a multi-function device disappears. The problem with this however is that due to the requirement of artificial MMIO addreesses (address cookies) extra logic is then needed to keep the address cookies compatible on re-plug. At the same time the MMIO resources semantically belong to the PCI function so tying their lifecycle to the function seems more logical. Instead a simpler approach is to remove the resources of an individually hot-unplugged PCI function from the PCI bus's resource list while keeping the resources of other PCI functions on the PCI bus untouched. This is done by introducing pci_bus_remove_resource() to remove an individual resource. Similarly the resource also needs to be removed from the struct zpci_bus's resource list. It turns out however, that there is really no need to add the MMIO resources to the struct zpci_bus's resource list at all and instead we can simply use the zpci_bar_struct's resource pointer directly. Fixes: a50297cf8235 ("s390/pci: separate zbus creation from scanning") Signed-off-by: Niklas Schnelle Reviewed-by: Matthew Rosato Acked-by: Bjorn Helgaas Link: https://lore.kernel.org/r/20230306151014.60913-2-schnelle@linux.ibm.com Signed-off-by: Vasily Gorbik

PCI: Skip allocate_resource() if too little space available

2022-12-10T16:31:47+00:00

pci_bus_alloc_from_region() allocates MMIO space by iterating through all the resources available on the bus. The available resource might be reduced if the caller requires 32-bit space or we're avoiding BIOS or E820 areas. Don't bother calling allocate_resource() if we need more space than is available in this resource. This prevents some pointless and annoying messages about avoided areas. Link: https://lore.kernel.org/r/20221208190341.1560157-3-helgaas@kernel.org Signed-off-by: Bjorn Helgaas Acked-by: Hans de Goede

PCI: Add device even if driver attach failed

2020-07-07T22:33:41+00:00

device_attach() returning failure indicates a driver error while trying to probe the device. In such a scenario, the PCI device should still be added in the system and be visible to the user. When device_attach() fails, merely warn about it and keep the PCI device in the system. This partially reverts ab1a187bba5c ("PCI: Check device_attach() return value always"). Link: https://lore.kernel.org/r/20200706233240.3245512-1-rajatja@google.com Signed-off-by: Rajat Jain Signed-off-by: Bjorn Helgaas Reviewed-by: Greg Kroah-Hartman Cc: stable@vger.kernel.org # v4.6+

PCI: Unexport pci_bus_get() and pci_bus_put()

2019-07-23T23:32:49+00:00

pci_bus_get() and pci_bus_put() are not used by a loadable kernel module and do not need to be exported. These were exported by fe830ef62ac6 ("PCI: Introduce pci_bus_{get|put}() to manage PCI bus reference count"), but there are no loadable modules in the tree that use them. Link: https://lore.kernel.org/r/20190717182353.45557-1-skunberg.kelsey@gmail.com Signed-off-by: Kelsey Skunberg Signed-off-by: Bjorn Helgaas Acked-by: Greg Kroah-Hartman