linux-toradex.git/drivers/pci/pcie, branch v4.9.123

PCI/ASPM: Deal with missing root ports in link state handling

2018-03-11T15:21:30+00:00

commit ee8bdfb6568d86bb93f55f8d99c4c643e77304ee upstream.

Even though it is unconventional, some PCIe host implementations omit the
root ports entirely, and simply consist of a host bridge (which is not
modeled as a device in the PCI hierarchy) and a link.

When the downstream device is an endpoint, our current code does not seem
to mind this unusual configuration. However, when PCIe switches are
involved, the ASPM code assumes that any downstream switch port has a
parent, and blindly dereferences the bus->parent->self field of the pci_dev
struct to chain the downstream link state to the link state of the root
port. Given that the root port is missing, the link is not modeled at all,
and nor is the link state, and attempting to access it results in a NULL
pointer dereference and a crash.

Avoid this by allowing the link state chain to terminate at the downstream
port if no root port exists.

Signed-off-by: Ard Biesheuvel 
Signed-off-by: Bjorn Helgaas 
Signed-off-by: Greg Kroah-Hartman

PCI/AER: Report non-fatal errors only to the affected endpoint

2017-12-25T13:23:44+00:00

[ Upstream commit 86acc790717fb60fb51ea3095084e331d8711c74 ]

Previously, if an non-fatal error was reported by an endpoint, we
called report_error_detected() for the endpoint, every sibling on the
bus, and their descendents.  If any of them did not implement the
.error_detected() method, do_recovery() failed, leaving all these
devices unrecovered.

For example, the system described in the bugzilla below has two devices:

  0000:74:02.0 [19e5:a230] SAS controller, driver has .error_detected()
  0000:74:03.0 [19e5:a235] SATA controller, driver lacks .error_detected()

When a device such as 74:02.0 reported a non-fatal error, do_recovery()
failed because 74:03.0 lacked an .error_detected() method.  But per PCIe
r3.1, sec 6.2.2.2.2, such an error does not compromise the Link and
does not affect 74:03.0:

  Non-fatal errors are uncorrectable errors which cause a particular
  transaction to be unreliable but the Link is otherwise fully functional.
  Isolating Non-fatal from Fatal errors provides Requester/Receiver logic
  in a device or system management software the opportunity to recover from
  the error without resetting the components on the Link and disturbing
  other transactions in progress.  Devices not associated with the
  transaction in error are not impacted by the error.

Report non-fatal errors only to the endpoint that reported them.  We really
want to check for AER_NONFATAL here, but the current code structure doesn't
allow that.  Looking for pci_channel_io_normal is the best we can do now.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=197055
Fixes: 6c2b374d7485 ("PCI-Express AER implemetation: AER core and aerdriver")
Signed-off-by: Gabriele Paoloni 
Signed-off-by: Dongdong Liu 
[bhelgaas: changelog]
Signed-off-by: Bjorn Helgaas 

Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

PCI/PME: Handle invalid data when reading Root Status

2017-12-20T09:07:27+00:00

[ Upstream commit 3ad3f8ce50914288731a3018b27ee44ab803e170 ]

PCIe PME and native hotplug share the same interrupt number, so hotplug
interrupts are also processed by PME.  In some cases, e.g., a Link Down
interrupt, a device may be present but unreachable, so when we try to
read its Root Status register, the read fails and we get all ones data
(0xffffffff).

Previously, we interpreted that data as PCI_EXP_RTSTA_PME being set, i.e.,
"some device has asserted PME," so we scheduled pcie_pme_work_fn().  This
caused an infinite loop because pcie_pme_work_fn() tried to handle PME
requests until PCI_EXP_RTSTA_PME is cleared, but with the link down,
PCI_EXP_RTSTA_PME can't be cleared.

Check for the invalid 0xffffffff data everywhere we read the Root Status
register.

1469d17dd341 ("PCI: pciehp: Handle invalid data when reading from
non-existent devices") added similar checks in the hotplug driver.

Signed-off-by: Qiang Zheng 
[bhelgaas: changelog, also check in pcie_pme_work_fn(), use "~0" to follow
other similar checks]
Signed-off-by: Bjorn Helgaas 

Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

PCI/PME: Restore pcie_pme_driver.remove

2017-02-23T16:44:36+00:00

commit afe3e4d11bdf50a4c3965eb6465ba6bebbcf5dcf upstream.

In addition to making PME non-modular, d7def2040077 ("PCI/PME: Make
explicitly non-modular") removed the pcie_pme_driver .remove() method,
pcie_pme_remove().

pcie_pme_remove() freed the PME IRQ that was requested in pci_pme_probe().
The fact that we don't free the IRQ after d7def2040077 causes the following
crash when removing a PCIe port device via /sys:

  ------------[ cut here ]------------
  kernel BUG at drivers/pci/msi.c:370!
  invalid opcode: 0000 [#1] SMP
  Modules linked in:
  CPU: 1 PID: 14509 Comm: sh Tainted: G    W  4.8.0-rc1-yh-00012-gd29438d
  RIP: 0010:[]  free_msi_irqs+0x65/0x190
  ...
  Call Trace:
   [] pci_disable_msi+0x34/0x40
   [] cleanup_service_irqs+0x27/0x30
   [] pcie_port_device_remove+0x2a/0x40
   [] pcie_portdrv_remove+0x40/0x50
   [] pci_device_remove+0x4b/0xc0
   [] __device_release_driver+0xb6/0x150
   [] device_release_driver+0x25/0x40
   [] pci_stop_bus_device+0x74/0xa0
   [] pci_stop_and_remove_bus_device_locked+0x1a/0x30
   [] remove_store+0x50/0x70
   [] dev_attr_store+0x18/0x30
   [] sysfs_kf_write+0x44/0x60
   [] kernfs_fop_write+0x10e/0x190
   [] __vfs_write+0x28/0x110
   [] ? percpu_down_read+0x44/0x80
   [] ? __sb_start_write+0xa7/0xe0
   [] ? __sb_start_write+0xa7/0xe0
   [] vfs_write+0xc4/0x180
   [] SyS_write+0x49/0xa0
   [] do_syscall_64+0xa6/0x1b0
   [] entry_SYSCALL64_slow_path+0x25/0x25
  ...
   RIP  [] free_msi_irqs+0x65/0x190
   RSP 
  ---[ end trace f4505e1dac5b95d3 ]---
  Segmentation fault

Restore pcie_pme_remove().

[bhelgaas: changelog]
Fixes: d7def2040077 ("PCI/PME: Make explicitly non-modular")
Signed-off-by: Yinghai Lu 
Signed-off-by: Bjorn Helgaas 
Acked-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

PCI/ASPM: Handle PCI-to-PCIe bridges as roots of PCIe hierarchies

2017-02-09T07:08:25+00:00

commit 030305d69fc6963c16003f50d7e8d74b02d0a143 upstream.

In a struct pcie_link_state, link->root points to the pcie_link_state of
the root of the PCIe hierarchy.  For the topmost link, this points to
itself (link->root = link).  For others, we copy the pointer from the
parent (link->root = link->parent->root).

Previously we recognized that Root Ports originated PCIe hierarchies, but
we treated PCI/PCI-X to PCIe Bridges as being in the middle of the
hierarchy, and when we tried to copy the pointer from link->parent->root,
there was no parent, and we dereferenced a NULL pointer:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000090
  IP: [] pcie_aspm_init_link_state+0x170/0x820

Recognize that PCI/PCI-X to PCIe Bridges originate PCIe hierarchies just
like Root Ports do, so link->root for these devices should also point to
itself.

Fixes: 51ebfc92b72b ("PCI: Enumerate switches below PCI-to-PCIe bridges")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=193411
Link: https://bugzilla.opensuse.org/show_bug.cgi?id=1022181
Tested-by: lists@ssl-mail.com
Tested-by: Jayachandran C. 
Signed-off-by: Bjorn Helgaas 
Signed-off-by: Greg Kroah-Hartman

PCI: Export pcie_find_root_port

2016-11-23T22:23:23+00:00

Export pcie_find_root_port() so we can use it outside of PCIe-AER error
injection.

Signed-off-by: Johannes Thumshirn 
Signed-off-by: Bjorn Helgaas

Merge branch 'pci/aer' into next

2016-10-03T14:42:57+00:00

* pci/aer:
  PCI/AER: Fix aer_probe() kernel-doc comment
  PCI/AER: Cache capability position
  PCI/AER: Avoid memory allocation in interrupt handling path
  ACPI / APEI: Send correct severity to calculate AER severity
  PCI/AER: Remove duplicate AER severity translation
  PCI/AER: Remove aerdriver.forceload kernel parameter
  PCI/AER: Remove aerdriver.nosourceid kernel parameter
  x86/PCI: VMD: Add quirk for AER to ignore source ID
  PCI/AER: Add bus flag to skip source ID matching

Conflicts:
	drivers/pci/probe.c

PCI/AER: Fix aer_probe() kernel-doc comment

2016-09-30T15:06:23+00:00

0516c8bcd252 ("PCI: PCIe portdrv: Simplily probe callback of service
drivers") removed the "id" argument of aer_probe() but neglected to remove
the kernel-doc comment.  Update the comment.

[bhelgaas: changelog]
Signed-off-by: Cao jin 
Signed-off-by: Bjorn Helgaas

PCI/AER: Cache capability position

2016-09-27T21:01:49+00:00

Save the position of the error reporting capability so it doesn't need to
be rediscovered during error handling.

Signed-off-by: Keith Busch 
Signed-off-by: Bjorn Helgaas 
CC: Lukas Wunner

PCI/AER: Avoid memory allocation in interrupt handling path

2016-09-27T19:30:36+00:00

When handling AER events, we previously allocated a struct aer_err_info,
processed the error, and freed the struct.  But aer_isr_one_error() is
serialized by rpc_mutex, so we never need more than one copy of the struct,
and the struct is only about 70 bytes, so we're not saving much by
allocating it dynamically.

Embed a struct aer_err_info directly in struct aer_rpc, which is allocated
at probe-time by aer_probe().

[bhelgaas: changelog]
Suggested-by: Bjorn Helgaas 
Signed-off-by: Jon Derrick 
Signed-off-by: Bjorn Helgaas