kernel/linux.git/drivers/pci/hotplug, branch v5.15.7

s390/pci: fix zpci_zdev_put() on reserve

2021-10-04T07:49:10+00:00

Since commit 2a671f77ee49 ("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: 2a671f77ee49 ("s390/pci: fix use after free of zpci_dev") Cc: stable@vger.kernel.org Signed-off-by: Niklas Schnelle Signed-off-by: Vasily Gorbik

Merge branch 'pci/reset'

2021-09-02T19:56:42+00:00

- 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

PCI: ibmphp: Fix double unmap of io_mem

2021-09-02T17:02:50+00:00

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 Signed-off-by: Bjorn Helgaas

PCI: Change the type of probe argument in reset functions

2021-08-18T22:32:42+00:00

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 Link: https://lore.kernel.org/r/20210817180500.1253-10-ameynarkhede03@gmail.com Signed-off-by: Amey Narkhede Signed-off-by: Bjorn Helgaas

Merge branch 'pci/kernel-doc'

2021-07-06T15:56:29+00:00

- Fix kernel-doc formatting errors (Krzysztof Wilczyński) * pci/kernel-doc: PCI: Fix kernel-doc formatting

Merge branch 'pci/sysfs'

2021-07-06T15:56:25+00:00

- Fix dsm_label_utf16s_to_utf8s() buffer overrun (Krzysztof Wilczyński) - Use sysfs_emit() and sysfs_emit_at() in "show" functions (Krzysztof Wilczyński) - Fix 'resource_alignment' newline issues (Krzysztof Wilczyński) - Add newline to 'devspec' sysfs file (Krzysztof Wilczyński) * pci/sysfs: PCI/sysfs: Add 'devspec' newline PCI/sysfs: Fix 'resource_alignment' newline issues PCI/sysfs: Use sysfs_emit() and sysfs_emit_at() in "show" functions PCI/sysfs: Rely on lengths from scnprintf(), dsm_label_utf16s_to_utf8s() PCI/sysfs: Fix dsm_label_utf16s_to_utf8s() buffer overrun # Conflicts: # drivers/pci/p2pdma.c

PCI: Fix kernel-doc formatting

2021-07-06T15:37:46+00:00

Fix kernel-doc formatting throughout drivers/pci and related include files. No change to functionality intended. Check for warnings: $ find include drivers/pci -type f -path "*pci*.[ch]" | xargs scripts/kernel-doc -none [bhelgaas: squashed to one commit] Link: https://lore.kernel.org/r/20210509030237.368540-1-kw@linux.com Link: https://lore.kernel.org/r/20210703151306.1922450-1-kw@linux.com Link: https://lore.kernel.org/r/20210703151306.1922450-2-kw@linux.com Link: https://lore.kernel.org/r/20210703151306.1922450-3-kw@linux.com Link: https://lore.kernel.org/r/20210703151306.1922450-4-kw@linux.com Link: https://lore.kernel.org/r/20210703151306.1922450-5-kw@linux.com Signed-off-by: Krzysztof Wilczyński Signed-off-by: Bjorn Helgaas

PCI: cpcihp: Declare cpci_debug in header file

2021-07-01T20:32:45+00:00

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 Signed-off-by: Bjorn Helgaas

PCI: pciehp: Ignore Link Down/Up caused by DPC

2021-06-16T22:16:57+00:00

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 Reported-by: Ethan Zhao Reported-by: Kuppuswamy Sathyanarayanan Tested-by: Kuppuswamy Sathyanarayanan Tested-by: Yicong Yang Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Reviewed-by: Kuppuswamy Sathyanarayanan Cc: Dan Williams Cc: Ashok Raj Cc: Keith Busch

PCI/sysfs: Use sysfs_emit() and sysfs_emit_at() in "show" functions

2021-06-04T03:14:47+00:00

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: ad025f8e46f3 ("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 Signed-off-by: Bjorn Helgaas Reviewed-by: Logan Gunthorpe