linux-toradex.git/drivers/pci/hotplug, branch v2.6.30.5

PCI Hotplug: acpiphp: don't store a pci_dev in acpiphp_func

2009-05-27T09:04:24+00:00

An oops can occur if a user attempts to use both PCI logical
hotplug and the ACPI physical hotplug driver (acpiphp) in this
sequence, where $slot/address == $device.

In other words, if acpiphp has claimed a PCI device, and that
device is logically removed, then acpiphp may oops when it
attempts to access it again.

	# echo 1 > /sys/bus/pci/devices/$device/remove
	# echo 0 > /sys/bus/pci/slots/$slot/power

Unable to handle kernel NULL pointer dereference (address 0000000000000000)
Call Trace:
 [] show_stack+0x50/0xa0
 [] show_regs+0x820/0x860
 [] die+0x190/0x2a0
 [] ia64_do_page_fault+0x8e0/0xa40
 [] ia64_native_leave_kernel+0x0/0x270
 [] pci_remove_bus_device+0x120/0x260
 [] acpiphp_disable_slot+0x410/0x540 [acpiphp]
 [] disable_slot+0xc0/0x120 [acpiphp]
 [] power_write_file+0x1e0/0x2a0 [pci_hotplug]
 [] pci_slot_attr_store+0x60/0xa0
 [] sysfs_write_file+0x230/0x2c0
 [] vfs_write+0x190/0x2e0
 [] sys_write+0x80/0x100
 [] ia64_ret_from_syscall+0x0/0x20
 [] __kernel_syscall_via_break+0x0/0x20

The root cause of this oops is that the logical remove ("echo 1 >
/sys/bus/pci/devices/$device/remove") destroyed the pci_dev. The
pci_dev struct itself wasn't deallocated because acpiphp kept a
reference, but some of its fields became invalid.

acpiphp doesn't have any real reason to keep a pointer to a
pci_dev around. It can always derive it using pci_get_slot().

If a logical remove destroys the pci_dev, acpiphp won't find it
and is thus prevented from causing mischief.

Reviewed-by: Matthew Wilcox 
Reviewed-by: Kenji Kaneshige 
Tested-by: Kenji Kaneshige 
Reported-by: Kenji Kaneshige 
Acked-by: Bjorn Helgaas 
Signed-off-by: Alex Chiang 
Signed-off-by: Jesse Barnes

PCI Hotplug: acpiphp: grab refcount on p2p subordinate bus

2009-04-06T18:30:26+00:00

If a logical hot unplug (remove) is performed on a bridge claimed
by acpiphp and then acpiphp is unloaded, we will encounter an oops.

This is because acpiphp will access the bridge's subordinate bus,
which was released by the user's prior hot unplug.

The solution is to grab a reference on the subordinate PCI bus.
This will prevent the bus from release until acpiphp is unloaded.

Reviewed-by: Kenji Kaneshige 
Tested-by: Kenji Kaneshige 
Reported-by: Kenji Kaneshige 
Signed-off-by: Alex Chiang 
Signed-off-by: Jesse Barnes

PCI: update fakephp for bus_id removal

2009-03-26T23:00:34+00:00

Get rid of a new use of bus_id that snuck in.

Signed-off-by: Stephen Rothwell 
Signed-off-by: Jesse Barnes

PCI Hotplug: rename legacy_fakephp to fakephp

2009-03-20T21:59:37+00:00

We wanted to replace fakephp wholesale, so rename legacy_fakephp back
to fakephp. Yes, this is a silly commit, but it produces a much easier
patch to read and review.

Signed-off-by: Alex Chiang 
Signed-off-by: Jesse Barnes

PCI Hotplug: restore fakephp interface with complete reimplementation

2009-03-20T21:59:25+00:00

A complete re-implementation of fakephp is necessary if it is to
present its former interface (pre-2.6.27, when it broke). The
reason is that PCI hotplug drivers call pci_hp_register(), which
enforces the rule that only one /sys/bus/pci/slots/ file may be
created per physical slot.

The change breaks the old fakephp's assumption that it could
create a file per function. So we re-implement fakephp to avoid
using the standard PCI hotplug API so that we can restore the old
fakephp user interface.

It puts entries in /sys/bus/pci/slots with the names of all PCI
devices/functions, exactly symmetrical to what is shown in
/sys/bus/pci/devices. Each slots/ entry has a "power" attribute,
which works the same way as the fakephp driver's power attribute
has worked.

There are a few improvements over old fakephp, which couldn't handle
PCI devices being added or removed via a means outside of
fakephp's knowledge.  If a device was added another way, old fakephp
didn't notice and didn't create the fake slot for it.  If a
device was removed another way, old fakephp didn't delete the fake
slot for it (and accessing the stale slot caused an oops).

The new implementation overcomes these limitations. As a
consequence, removing a bridge with other devices behind it now
works as well, which is something else old fakephp couldn't do
previously.

This duplicates a tiny bit of the code in the PCI core that does
this same function.  Re-using that code ends up being more
complex than duplicating it, and it makes code in the PCI core
more ugly just to support this legacy fakephp interface
compatibility layer.

Reviewed-by: James Cameron 
Signed-off-by: Trent Piepho 
Signed-off-by: Alex Chiang 
Signed-off-by: Jesse Barnes

PCI: Introduce pci_rescan_bus()

2009-03-20T21:57:44+00:00

This API is used by the PCI core to rescan a bus and rediscover
newly added devices.

Over time, it is expected that the various PCI hotplug drivers
will migrate to this interface and away from the old
pci_do_scan_bus() interface.

Signed-off-by: Alex Chiang 
Signed-off-by: Jesse Barnes

PCI hotplug: fix wrong assumption in acpi_get_hp_hw_control_from_firmware

2009-03-20T17:48:02+00:00

Current acpi_get_hp_hw_control_from_firmware() has a assumption that
pci_bus->self is NULL on a PCI root bus. But it might not be true on
some platforms. Because of this wrong assumption, current
acpi_get_hp_hw_control_from_firmware() might cause endless loop. We
must check pci_bus->parent instead.

Signed-off-by: Kenji Kaneshige 
Signed-off-by: Jesse Barnes

PCI hotplug: fix wrong assumption in acpi_get_hp_params_from_firmware

2009-03-20T17:48:00+00:00

Current acpi_get_hp_params_from_firmware() has a assumption that
pci_bus->self is NULL on the root pci bus. But it might not true on
some platforms. Because of this wrong assumption, current
acpi_get_hp_params_from_firmware() might cause endless loop. We must
check pci_bus->parent instead.

Signed-off-by: Kenji Kaneshige 
Signed-off-by: Jesse Barnes

PCI: PCIe portdrv: Implement pm object

2009-03-20T17:47:49+00:00

Implement pm object for the PCI Express port driver in order to use
the new power management framework and reduce the code size.

Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Jesse Barnes

PCI hotplug: shpchp: fix bus number check to avoid false positive

2009-03-20T02:29:33+00:00

With for (busnr = 0; busnr <= end; busnr++) { ... } busnr reaches end + 1
after the loop.  So fix the "no busses available" check to look for just
busnr > end rather than >=.

Signed-off-by: Roel Kluin 
Signed-off-by: Jesse Barnes