user/sven/linux.git/drivers/pci/hotplug, branch v4.19.170

PCI: pciehp: Fix MSI interrupt race

2020-10-01T11:14:41Z

[ Upstream commit 8edf5332c39340b9583cf9cba659eb7ec71f75b5 ] Without this commit, a PCIe hotplug port can stop generating interrupts on hotplug events, so device adds and removals will not be seen: The pciehp interrupt handler pciehp_isr() reads the Slot Status register and then writes back to it to clear the bits that caused the interrupt. If a different interrupt event bit gets set between the read and the write, pciehp_isr() returns without having cleared all of the interrupt event bits. If this happens when the MSI isn't masked (which by default it isn't in handle_edge_irq(), and which it will never be when MSI per-vector masking is not supported), we won't get any more hotplug interrupts from that device. That is expected behavior, according to the PCIe Base Spec r5.0, section 6.7.3.4, "Software Notification of Hot-Plug Events". Because the Presence Detect Changed and Data Link Layer State Changed event bits can both get set at nearly the same time when a device is added or removed, this is more likely to happen than it might seem. The issue was found (and can be reproduced rather easily) by connecting and disconnecting an NVMe storage device on at least one system model where the NVMe devices were being connected to an AMD PCIe port (PCI device 0x1022/0x1483). Fix the issue by modifying pciehp_isr() to loop back and re-read the Slot Status register immediately after writing to it, until it sees that all of the event status bits have been cleared. [lukas: drop loop count limitation, write "events" instead of "status", don't loop back in INTx and poll modes, tweak code comment & commit msg] Link: https://lore.kernel.org/r/78b4ced5072bfe6e369d20e8b47c279b8c7af12e.1582121613.git.lukas@wunner.de Tested-by: Stuart Hayes Signed-off-by: Stuart Hayes Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Reviewed-by: Joerg Roedel Signed-off-by: Sasha Levin

PCI: hotplug: ACPI: Fix context refcounting in acpiphp_grab_context()

2020-08-21T09:05:29Z

commit dae68d7fd4930315389117e9da35b763f12238f9 upstream. If context is not NULL in acpiphp_grab_context(), but the is_going_away flag is set for the device's parent, the reference counter of the context needs to be decremented before returning NULL or the context will never be freed, so make that happen. Fixes: edf5bf34d408 ("ACPI / dock: Use callback pointers from devices' ACPI hotplug contexts") Reported-by: Vasily Averin Cc: 3.15+ # 3.15+ Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

PCI: pciehp: Fix indefinite wait on sysfs requests

2020-04-17T08:48:45Z

commit 3e487d2e4aa466decd226353755c9d423e8fbacc upstream. David Hoyer reports that powering pciehp slots up or down via sysfs may hang: The call to wait_event() in pciehp_sysfs_enable_slot() and _disable_slot() does not return because ctrl->ist_running remains true. This flag, which was introduced by commit 157c1062fcd8 ("PCI: pciehp: Avoid returning prematurely from sysfs requests"), signifies that the IRQ thread pciehp_ist() is running. It is set to true at the top of pciehp_ist() and reset to false at the end. However there are two additional return statements in pciehp_ist() before which the commit neglected to reset the flag to false and wake up waiters for the flag. That omission opens up the following race when powering up the slot: * pciehp_ist() runs because a PCI_EXP_SLTSTA_PDC event was requested by pciehp_sysfs_enable_slot() * pciehp_ist() turns on slot power via the following call stack: pciehp_handle_presence_or_link_change() -> pciehp_enable_slot() -> __pciehp_enable_slot() -> board_added() -> pciehp_power_on_slot() * after slot power is turned on, the link comes up, resulting in a PCI_EXP_SLTSTA_DLLSC event * the IRQ handler pciehp_isr() stores the event in ctrl->pending_events and returns IRQ_WAKE_THREAD * the IRQ thread is already woken (it's bringing up the slot), but the genirq code remembers to re-run the IRQ thread after it has finished (such that it can deal with the new event) by setting IRQTF_RUNTHREAD via __handle_irq_event_percpu() -> __irq_wake_thread() * the IRQ thread removes PCI_EXP_SLTSTA_DLLSC from ctrl->pending_events via board_added() -> pciehp_check_link_status() in order to deal with presence and link flaps per commit 6c35a1ac3da6 ("PCI: pciehp: Tolerate initially unstable link") * after pciehp_ist() has successfully brought up the slot, it resets ctrl->ist_running to false and wakes up the sysfs requester * the genirq code re-runs pciehp_ist(), which sets ctrl->ist_running to true but then returns with IRQ_NONE because ctrl->pending_events is empty * pciehp_sysfs_enable_slot() is finally woken but notices that ctrl->ist_running is true, hence continues waiting The only way to get the hung task going again is to trigger a hotplug event which brings down the slot, e.g. by yanking out the card. The same race exists when powering down the slot because remove_board() likewise clears link or presence changes in ctrl->pending_events per commit 3943af9d01e9 ("PCI: pciehp: Ignore Link State Changes after powering off a slot") and thereby may cause a re-run of pciehp_ist() which returns with IRQ_NONE without resetting ctrl->ist_running to false. Fix by adding a goto label before the teardown steps at the end of pciehp_ist() and jumping to that label from the two return statements which currently neglect to reset the ctrl->ist_running flag. Fixes: 157c1062fcd8 ("PCI: pciehp: Avoid returning prematurely from sysfs requests") Link: https://lore.kernel.org/r/cca1effa488065cb055120aa01b65719094bdcb5.1584530321.git.lukas@wunner.de Reported-by: David Hoyer Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Reviewed-by: Keith Busch Cc: stable@vger.kernel.org # v4.19+ Signed-off-by: Greg Kroah-Hartman

PCI: rpaphp: Correctly match ibm, my-drc-index to drc-name when using drc-info

2020-01-04T18:12:55Z

[ Upstream commit 4f9f2d3d7a434b7f882b72550194c9278f4a3925 ] The newer ibm,drc-info property is a condensed description of the old ibm,drc-* properties (ie. names, types, indexes, and power-domains). When matching a drc-index to a drc-name we need to verify that the index is within the start and last drc-index range and map it to a drc-name using the drc-name-prefix and logical index. Fix the mapping by checking that the index is within the range of the current drc-info entry, and build the name from the drc-name-prefix concatenated with the starting drc-name-suffix value and the sequential index obtained by subtracting ibm,my-drc-index from this entries drc-start-index. Signed-off-by: Tyrel Datwyler Acked-by: Bjorn Helgaas Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1573449697-5448-10-git-send-email-tyreld@linux.ibm.com Signed-off-by: Sasha Levin

PCI: rpaphp: Annotate and correctly byte swap DRC properties

2020-01-04T18:12:54Z

[ Upstream commit 0737686778c6dbe0908d684dd5b9c05b127526ba ] The device tree is in big endian format and any properties directly retrieved using OF helpers that don't explicitly byte swap should be annotated. In particular there are several places where we grab the opaque property value for the old ibm,drc-* properties and the ibm,my-drc-index property. Fix this for better static checking by annotating values we know to explicitly big endian, and byte swap where appropriate. Signed-off-by: Tyrel Datwyler Acked-by: Bjorn Helgaas Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1573449697-5448-9-git-send-email-tyreld@linux.ibm.com Signed-off-by: Sasha Levin

PCI: rpaphp: Don't rely on firmware feature to imply drc-info support

2020-01-04T18:12:54Z

[ Upstream commit 52e2b0f16574afd082cff0f0e8567b2d9f68c033 ] In the event that the partition is migrated to a platform with older firmware that doesn't support the ibm,drc-info property the device tree is modified to remove the ibm,drc-info property and replace it with the older style ibm,drc-* properties for types, names, indexes, and power-domains. One of the requirements of the drc-info firmware feature is that the client is able to handle both the new property, and old style properties at runtime. Therefore we can't rely on the firmware feature alone to dictate which property is currently present in the device tree. Fix this short coming by checking explicitly for the ibm,drc-info property, and falling back to the older ibm,drc-* properties if it doesn't exist. Signed-off-by: Tyrel Datwyler Acked-by: Bjorn Helgaas Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1573449697-5448-6-git-send-email-tyreld@linux.ibm.com Signed-off-by: Sasha Levin

PCI: rpaphp: Fix up pointer to first drc-info entry

2020-01-04T18:12:53Z

[ Upstream commit 9723c25f99aff0451cfe6392e1b9fdd99d0bf9f0 ] The first entry of the ibm,drc-info property is an int encoded count of the number of drc-info entries that follow. The "value" pointer returned by of_prop_next_u32() is still pointing at the this value when we call of_read_drc_info_cell(), but the helper function expects that value to be pointing at the first element of an entry. Fix up by incrementing the "value" pointer to point at the first element of the first drc-info entry prior. Signed-off-by: Tyrel Datwyler Acked-by: Bjorn Helgaas Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1573449697-5448-5-git-send-email-tyreld@linux.ibm.com Signed-off-by: Sasha Levin

PCI: pciehp: Avoid returning prematurely from sysfs requests

2019-12-21T09:57:22Z

commit 157c1062fcd86ade3c674503705033051fd3d401 upstream. A sysfs request to enable or disable a PCIe hotplug slot should not return before it has been carried out. That is sought to be achieved by waiting until the controller's "pending_events" have been cleared. However the IRQ thread pciehp_ist() clears the "pending_events" before it acts on them. If pciehp_sysfs_enable_slot() / _disable_slot() happen to check the "pending_events" after they have been cleared but while pciehp_ist() is still running, the functions may return prematurely with an incorrect return value. Fix by introducing an "ist_running" flag which must be false before a sysfs request is allowed to return. Fixes: 32a8cef274fe ("PCI: pciehp: Enable/disable exclusively from IRQ thread") Link: https://lore.kernel.org/linux-pci/1562226638-54134-1-git-send-email-wangxiongfeng2@huawei.com Link: https://lore.kernel.org/r/4174210466e27eb7e2243dd1d801d5f75baaffd8.1565345211.git.lukas@wunner.de Reported-and-tested-by: Xiongfeng Wang Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Cc: stable@vger.kernel.org # v4.19+ Signed-off-by: Greg Kroah-Hartman

ACPI / hotplug / PCI: Allocate resources directly under the non-hotplug bridge

2019-12-17T19:35:04Z

commit 77adf9355304f8dcf09054280af5e23fc451ab3d upstream. Valerio and others reported that commit 84c8b58ed3ad ("ACPI / hotplug / PCI: Don't scan bridges managed by native hotplug") prevents some recent LG and HP laptops from booting with endless loop of: ACPI Error: No handler or method for GPE 08, disabling event (20190215/evgpe-835) ACPI Error: No handler or method for GPE 09, disabling event (20190215/evgpe-835) ACPI Error: No handler or method for GPE 0A, disabling event (20190215/evgpe-835) ... What seems to happen is that during boot, after the initial PCI enumeration when EC is enabled the platform triggers ACPI Notify() to one of the root ports. The root port itself looks like this: pci 0000:00:1b.0: PCI bridge to [bus 02-3a] pci 0000:00:1b.0: bridge window [mem 0xc4000000-0xda0fffff] pci 0000:00:1b.0: bridge window [mem 0x80000000-0xa1ffffff 64bit pref] The BIOS has configured the root port so that it does not have I/O bridge window. Now when the ACPI Notify() is triggered ACPI hotplug handler calls acpiphp_native_scan_bridge() for each non-hotplug bridge (as this system is using native PCIe hotplug) and pci_assign_unassigned_bridge_resources() to allocate resources. The device connected to the root port is a PCIe switch (Thunderbolt controller) with two hotplug downstream ports. Because of the hotplug ports __pci_bus_size_bridges() tries to add "additional I/O" of 256 bytes to each (DEFAULT_HOTPLUG_IO_SIZE). This gets further aligned to 4k as that's the minimum I/O window size so each hotplug port gets 4k I/O window and the same happens for the root port (which is also hotplug port). This means 3 * 4k = 12k I/O window. Because of this pci_assign_unassigned_bridge_resources() ends up opening a I/O bridge window for the root port at first available I/O address which seems to be in range 0x1000 - 0x3fff. Normally this range is used for ACPI stuff such as GPE bits (below is part of /proc/ioports): 1800-1803 : ACPI PM1a_EVT_BLK 1804-1805 : ACPI PM1a_CNT_BLK 1808-180b : ACPI PM_TMR 1810-1815 : ACPI CPU throttle 1850-1850 : ACPI PM2_CNT_BLK 1854-1857 : pnp 00:05 1860-187f : ACPI GPE0_BLK However, when the ACPI Notify() happened this range was not yet reserved for ACPI/PNP (that happens later) so PCI gets it. It then starts writing to this range and accidentally stomps over GPE bits among other things causing the endless stream of messages about missing GPE handler. This problem does not happen if "pci=hpiosize=0" is passed in the kernel command line. The reason is that then the kernel does not try to allocate the additional 256 bytes for each hotplug port. Fix this by allocating resources directly below the non-hotplug bridges where a new device may appear as a result of ACPI Notify(). This avoids the hotplug bridges and prevents opening the additional I/O window. Fixes: 84c8b58ed3ad ("ACPI / hotplug / PCI: Don't scan bridges managed by native hotplug") Link: https://bugzilla.kernel.org/show_bug.cgi?id=203617 Link: https://lore.kernel.org/r/20191030150545.19885-1-mika.westerberg@linux.intel.com Reported-by: Valerio Passini Signed-off-by: Mika Westerberg Signed-off-by: Bjorn Helgaas Reviewed-by: Rafael J. Wysocki Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

PCI: portdrv: Initialize service drivers directly

2019-11-20T17:47:10Z

[ Upstream commit c29de84149aba5f74e87b6491c13ac7203c12f55 ] The PCI port driver saves the PCI state after initializing the device with the applicable service devices. This was, however, before the service drivers were even registered because PCI probe happens before the device_initcall initialized those service drivers. The config space state that the services set up were not being saved. The end result would cause PCI devices to not react to events that the drivers think they did if the PCI state ever needed to be restored. Fix this by changing the service drivers from using the init calls to having the portdrv driver calling the services directly. This will get the state saved as desired, while making the relationship between the port driver and the services under it more explicit in the code. Signed-off-by: Keith Busch Signed-off-by: Bjorn Helgaas Reviewed-by: Sinan Kaya Signed-off-by: Sasha Levin