kernel.git/drivers/pci/access.c, branch linux-4.19.y

PCI: Reduce warnings on possible RW1C corruption

2022-04-15T12:14:50Z

[ Upstream commit 92c45b63ce22c8898aa41806e8d6692bcd577510 ] For hardware that only supports 32-bit writes to PCI there is the possibility of clearing RW1C (write-one-to-clear) bits. A rate-limited messages was introduced by fb2659230120, but rate-limiting is not the best choice here. Some devices may not show the warnings they should if another device has just produced a bunch of warnings. Also, the number of messages can be a nuisance on devices which are otherwise working fine. Change the ratelimit to a single warning per bus. This ensures no bus is 'starved' of emitting a warning and also that there isn't a continuous stream of warnings. It would be preferable to have a warning per device, but the pci_dev structure is not available here, and a lookup from devfn would be far too slow. Suggested-by: Bjorn Helgaas Fixes: fb2659230120 ("PCI: Warn on possible RW1C corruption for sub-32 bit config writes") Link: https://lore.kernel.org/r/20200806041455.11070-1-mark.tomlinson@alliedtelesis.co.nz Signed-off-by: Mark Tomlinson Signed-off-by: Bjorn Helgaas Reviewed-by: Florian Fainelli Reviewed-by: Rob Herring Acked-by: Scott Branden Signed-off-by: Sasha Levin

PCI: Fix pci_cfg_wait queue locking problem

2020-08-19T06:14:56Z

[ Upstream commit 2a7e32d0547f41c5ce244f84cf5d6ca7fccee7eb ] The pci_cfg_wait queue is used to prevent user-space config accesses to devices while they are recovering from reset. Previously we used these operations on pci_cfg_wait: __add_wait_queue(&pci_cfg_wait, ...) __remove_wait_queue(&pci_cfg_wait, ...) wake_up_all(&pci_cfg_wait) The wake_up acquires the wait queue lock, but the add and remove do not. Originally these were all protected by the pci_lock, but cdcb33f98244 ("PCI: Avoid possible deadlock on pci_lock and p->pi_lock"), moved wake_up_all() outside pci_lock, so it could race with add/remove operations, which caused occasional kernel panics, e.g., during vfio-pci hotplug/unplug testing: Unable to handle kernel read from unreadable memory at virtual address ffff802dac469000 Resolve this by using wait_event() instead of __add_wait_queue() and __remove_wait_queue(). The wait queue lock is held by both wait_event() and wake_up_all(), so it provides mutual exclusion. Fixes: cdcb33f98244 ("PCI: Avoid possible deadlock on pci_lock and p->pi_lock") Link: https://lore.kernel.org/linux-pci/79827f2f-9b43-4411-1376-b9063b67aee3@huawei.com/T/#u Based-on: https://lore.kernel.org/linux-pci/20191210031527.40136-1-zhengxiang9@huawei.com/ Based-on-patch-by: Xiang Zheng Signed-off-by: Bjorn Helgaas Tested-by: Xiang Zheng Cc: Heyi Guo Cc: Biaoxiang Ye Signed-off-by: Sasha Levin

Merge branch 'pci/vpd'

2018-04-04T18:28:40Z

- consolidate VPD code in vpd.c (Bjorn Helgaas) * pci/vpd: PCI/VPD: Move VPD structures to vpd.c PCI/VPD: Move VPD quirks to vpd.c PCI/VPD: Move VPD sysfs code to vpd.c PCI/VPD: Move VPD access code to vpd.c

PCI: Tidy comments

2018-03-19T19:20:43Z

Remove pointless comments that tell us the file name, remove blank line comments, follow multi-line comment conventions. No functional change intended. Signed-off-by: Bjorn Helgaas

PCI/VPD: Move VPD access code to vpd.c

2018-03-19T18:06:11Z

Move the VPD-related code from access.c to vpd.c. The goal is to encapsulate all the VPD code and structures in vpd.c. No functional change intended. Signed-off-by: Bjorn Helgaas

Merge branch 'pci/spdx' into next

2018-02-01T17:40:07Z

* pci/spdx: PCI: Add SPDX GPL-2.0+ to replace implicit GPL v2 or later statement PCI: Add SPDX GPL-2.0+ to replace GPL v2 or later boilerplate PCI: Add SPDX GPL-2.0 to replace COPYING boilerplate PCI: Add SPDX GPL-2.0 to replace GPL v2 boilerplate PCI: Add SPDX GPL-2.0 when no license was specified

PCI: Add SPDX GPL-2.0 when no license was specified

2018-01-26T17:45:16Z

b24413180f56 ("License cleanup: add SPDX GPL-2.0 license identifier to files with no license") added SPDX GPL-2.0 to several PCI files that previously contained no license information. Add SPDX GPL-2.0 to all other PCI files that did not contain any license information and hence were under the default GPL version 2 license of the kernel. Signed-off-by: Bjorn Helgaas Reviewed-by: Greg Kroah-Hartman

PCI: Add wrappers for dev_printk()

2018-01-18T18:55:24Z

Add PCI-specific dev_printk() wrappers and use them to simplify the code slightly. No functional change intended. Signed-off-by: Frederick Lawler [bhelgaas: squash into one patch] Signed-off-by: Bjorn Helgaas

PCI: Provide Kconfig option for lockless config space accessors

2017-06-28T20:32:56Z

The generic PCI configuration space accessors are globally serialized via pci_lock. On larger systems this causes massive lock contention when the configuration space has to be accessed frequently. One such access pattern is the Intel Uncore performance counter unit. Provide a kernel config option which can be selected by an architecture when the low level PCI configuration space accessors in the architecture use their own serialization or can operate completely lockless. Signed-off-by: Thomas Gleixner Acked-by: Bjorn Helgaas Cc: Andi Kleen Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Borislav Petkov Cc: linux-pci@vger.kernel.org Link: http://lkml.kernel.org/r/20170316215057.205961140@linutronix.de Signed-off-by: Thomas Gleixner

PCI: Make error code types consistent in pci_{read,write}_config_*

2017-05-26T21:38:50Z

Callers normally treat the config space accessors as returning PCBIOS_* error codes, not Linux error codes (or they don't look at them at all). We have pcibios_err_to_errno() in case the error code needs to be translated. Fixes: 4b1038834739 ("PCI: Don't attempt config access to disconnected devices") Signed-off-by: Brian Norris Signed-off-by: Bjorn Helgaas Reviewed-by: Keith Busch