Dennis reports a boot crash on recent Lenovo laptops with a USB4 dock.
Since commit 0fc7088656 ("thunderbolt: Reset USB4 v2 host router") and
commit 59a54c5f3d ("thunderbolt: Reset topology created by the boot
firmware"), USB4 v2 and v1 Host Routers are reset on probe of the
thunderbolt driver.
The reset clears the Presence Detect State and Data Link Layer Link Active
bits at the USB4 Host Router's Root Port and thus causes hot removal of the
dock.
The crash occurs when pciehp is unbound from one of the dock's Downstream
Ports: pciehp creates a pci_slot on bind and destroys it on unbind. The
pci_slot contains a pointer to the pci_bus below the Downstream Port, but
a reference on that pci_bus is never acquired. The pci_bus is destroyed
before the pci_slot, so a use-after-free ensues when pci_slot_release()
accesses slot->bus.
In principle this should not happen because pci_stop_bus_device() unbinds
pciehp (and therefore destroys the pci_slot) before the pci_bus is
destroyed by pci_remove_bus_device().
However the stacktrace provided by Dennis shows that pciehp is unbound from
pci_remove_bus_device() instead of pci_stop_bus_device(). To understand
the significance of this, one needs to know that the PCI core uses a two
step process to remove a portion of the hierarchy: It first unbinds all
drivers in the sub-hierarchy in pci_stop_bus_device() and then actually
removes the devices in pci_remove_bus_device(). There is no precaution to
prevent driver binding in-between pci_stop_bus_device() and
pci_remove_bus_device().
In Dennis' case, it seems removal of the hierarchy by pciehp races with
driver binding by pci_bus_add_devices(). pciehp is bound to the
Downstream Port after pci_stop_bus_device() has run, so it is unbound by
pci_remove_bus_device() instead of pci_stop_bus_device(). Because the
pci_bus has already been destroyed at that point, accesses to it result in
a use-after-free.
One might conclude that driver binding needs to be prevented after
pci_stop_bus_device() has run. However it seems risky that pci_slot points
to pci_bus without holding a reference. Solely relying on correct ordering
of driver unbind versus pci_bus destruction is certainly not defensive
programming.
If pci_slot has a need to access data in pci_bus, it ought to acquire a
reference. Amend pci_create_slot() accordingly. Dennis reports that the
crash is not reproducible with this change.
Abridged stacktrace:
pcieport 0000:00:07.0: PME: Signaling with IRQ 156
pcieport 0000:00:07.0: pciehp: Slot #12 AttnBtn- PwrCtrl- MRL- AttnInd- PwrInd- HotPlug+ Surprise+ Interlock- NoCompl+ IbPresDis- LLActRep+
pci_bus 0000:20: dev 00, created physical slot 12
pcieport 0000:00:07.0: pciehp: Slot(12): Card not present
...
pcieport 0000:21:02.0: pciehp: pcie_disable_notification: SLOTCTRL d8 write cmd 0
Oops: general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6b6b: 0000 [#1] PREEMPT SMP NOPTI
CPU: 13 UID: 0 PID: 134 Comm: irq/156-pciehp Not tainted 6.11.0-devel+ #1
RIP: 0010:dev_driver_string+0x12/0x40
pci_destroy_slot
pciehp_remove
pcie_port_remove_service
device_release_driver_internal
bus_remove_device
device_del
device_unregister
remove_iter
device_for_each_child
pcie_portdrv_remove
pci_device_remove
device_release_driver_internal
bus_remove_device
device_del
pci_remove_bus_device (recursive invocation)
pci_remove_bus_device
pciehp_unconfigure_device
pciehp_disable_slot
pciehp_handle_presence_or_link_change
pciehp_ist
Link: https://lore.kernel.org/r/4bfd4c0e976c1776cd08e76603903b338cf25729.1728579288.git.lukas@wunner.de
Reported-by: Dennis Wassenberg <Dennis.Wassenberg@secunet.com>
Closes: https://lore.kernel.org/r/6de4b45ff2b32dd91a805ec02ec8ec73ef411bf6.camel@secunet.com/
Tested-by: Dennis Wassenberg <Dennis.Wassenberg@secunet.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: stable@vger.kernel.org
Simplify pci_create_slot() by splitting an "if" statement into two parts.
In order to not duplicate error handling, add a new label to handle kobj
put.
Link: https://lore.kernel.org/r/20241004152240.7926-1-ilpo.jarvinen@linux.intel.com
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Since commit ee6d3dd4ed ("driver core: make kobj_type constant.") the
driver core allows the usage of const struct kobj_type.
Take advantage of this to constify the structure definition to prevent
modification at runtime.
Link: https://lore.kernel.org/r/20230216-kobj_type-pci-v1-1-46a63c8612b5@weissschuh.net
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
There are currently two ways to create a set of sysfs files for a
kobj_type: through the default_attrs field, and the default_groups field.
Move the PCI slot code to use the default_groups field which has been the
preferred way since aa30f47cf6 ("kobject: Add support for default
attribute groups to kobj_type") so that we can soon get rid of the obsolete
default_attrs field.
Link: https://lore.kernel.org/r/20211228135722.381023-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
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: ad025f8e46 ("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 <kw@linux.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
If kobject_init_and_add() fails, pci_slot_release() is called to delete
slot->list from parent->slots. But slot->list hasn't been initialized
yet, so we dereference a NULL pointer:
Unable to handle kernel NULL pointer dereference at virtual address
00000000
...
CPU: 10 PID: 1 Comm: swapper/0 Not tainted 4.4.240 #197
task: ffffeb398a45ef10 task.stack: ffffeb398a470000
PC is at __list_del_entry_valid+0x5c/0xb0
LR is at pci_slot_release+0x84/0xe4
...
__list_del_entry_valid+0x5c/0xb0
pci_slot_release+0x84/0xe4
kobject_put+0x184/0x1c4
pci_create_slot+0x17c/0x1b4
__pci_hp_initialize+0x68/0xa4
pciehp_probe+0x1a4/0x2fc
pcie_port_probe_service+0x58/0x84
driver_probe_device+0x320/0x470
Initialize slot->list before calling kobject_init_and_add() to avoid this.
Fixes: 8a94644b44 ("PCI: Fix pci_create_slot() reference count leak")
Link: https://lore.kernel.org/r/1606876422-117457-1-git-send-email-zhongjubin@huawei.com
Signed-off-by: Jubin Zhong <zhongjubin@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org # v5.9+
kobject_init_and_add() takes a reference even when it fails. If it returns
an error, kobject_put() must be called to clean up the memory associated
with the object.
When kobject_init_and_add() fails, call kobject_put() instead of kfree().
b8eb718348 ("net-sysfs: Fix reference count leak in
rx|netdev_queue_add_kobject") fixed a similar problem.
Link: https://lore.kernel.org/r/20200528021322.1984-1-wu000273@umn.edu
Signed-off-by: Qiushi Wu <wu000273@umn.edu>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Add pci_speed_string() to return a text description of the supplied bus or
link speed. The slot code previously used the private
pci_bus_speed_strings[] array for this purpose, but adding this interface
will enable us to consolidate similar code elsewhere.
Export pcie_link_speed[] and pci_speed_string() so they can be used by
modules.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
PCIe r5.0, sec 7.5.3.18, defines a new 32.0 GT/s bit in the Supported Link
Speeds Vector of Link Capabilities 2. Decode this new speed. This does
not affect the speed of the link, which should be negotiated automatically
by the hardware; it only adds decoding when showing the speed to the user.
Previously, reading the speed of a link operating at this speed showed
"Unknown speed" instead of "32.0 GT/s".
Link: https://lore.kernel.org/lkml/92365e3caf0fc559f9ab14bcd053bfc92d4f661c.1559664969.git.gustavo.pimentel@synopsys.com
Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
[bhelgaas: changelog]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
The secondary bus reset may have link side effects that a hotplug capable
port may incorrectly react to. Use the slot specific reset for hotplug
ports, fixing the undesirable link down-up handling during error
recovering.
Signed-off-by: Keith Busch <keith.busch@intel.com>
[bhelgaas: fold in
https://lore.kernel.org/linux-pci/20180926152326.14821-1-keith.busch@intel.com
for issue reported by Stephen Rothwell <sfr@canb.auug.org.au>]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Sinan Kaya <okaya@kernel.org>
Hotplug drivers cannot declare their hotplug_slot_ops const, making them
attractive targets for attackers, because upon registration of a hotplug
slot, __pci_hp_initialize() writes to the "owner" and "mod_name" members
in that struct.
Fix by moving these members to struct hotplug_slot and constify every
driver's hotplug_slot_ops except for pciehp.
pciehp constructs its hotplug_slot_ops at runtime based on the PCIe
port's capabilities, hence cannot declare them const. It can be
converted to __write_rarely once that's mainlined:
http://www.openwall.com/lists/kernel-hardening/2016/11/16/3
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com> # drivers/pci/hotplug/rpa*
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> # drivers/platform/x86
Cc: Len Brown <lenb@kernel.org>
Cc: Scott Murray <scott@spiteful.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Oliver OHalloran <oliveroh@au1.ibm.com>
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Corentin Chary <corentin.chary@gmail.com>
Cc: Darren Hart <dvhart@infradead.org>
- use PCI_EXP_DEVCTL2_COMP_TIMEOUT in rapidio/tsi721 (Bjorn Helgaas)
- remove possible NULL pointer dereference in of_pci_bus_find_domain_nr()
(Shawn Lin)
- report quirk timings with dev_info (Bjorn Helgaas)
- report quirks that take longer than 10ms (Bjorn Helgaas)
- add and use Altera Vendor ID (Johannes Thumshirn)
- tidy Makefiles and comments (Bjorn Helgaas)
* pci/misc:
PCI: Always define the of_node helpers
PCI: Tidy comments
PCI: Tidy Makefiles
mcb: Add Altera PCI ID to mcb-pci
PCI: Add Altera vendor ID
PCI: Report quirks that take more than 10ms
PCI: Report quirk timings with pci_info() instead of pr_debug()
PCI: Fix NULL pointer dereference in of_pci_bus_find_domain_nr()
rapidio/tsi721: use PCI_EXP_DEVCTL2_COMP_TIMEOUT macro
PCIe 4.0 defines the 16.0 GT/s link speed. Links can run at that speed
without any Linux changes, but previously their sysfs "max_link_speed" and
"current_link_speed" files contained "Unknown speed", not the expected
"16.0 GT/s".
Add decoding for the new 16 GT/s link speed.
Signed-off-by: Jay Fang <f.fangjian@huawei.com>
[bhelgaas: add PCI_EXP_LNKCAP2_SLS_16_0GB]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Dongdong Liu <liudongdong3@huawei.com>
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 <bhelgaas@google.com>
b24413180f ("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 <bhelgaas@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since we need to change the implementation, stop exposing internals.
Provide kref_read() to read the current reference count; typically
used for debug messages.
Kills two anti-patterns:
atomic_read(&kref->refcount)
kref->refcount.counter
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Previously, pci_setup_device() and similar functions searched the
pci_bus->slots list without any locking. It was possible for another
thread to update the list while we searched it.
Add pci_dev_assign_slot() to search the list while holding pci_slot_mutex.
[bhelgaas: changelog, fold in CONFIG_SYSFS fix]
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Rajat Jain reported a deadlock when PCIe hot-add and AER recovery happen at
the same time:
thread 1:
pciehp_enable_slot
pciehp_configure_device
pci_bus_add_devices
pci_bus_add_device
device_attach
device_lock(dev) # acquire device lock
...
pciehp_probe
init_slot
pci_hp_register
pci_create_slot
down_write(pci_bus_sem) # deadlock here
thread 2:
aer_isr_one_error
aer_process_err_device
do_recovery
broadcast_error_message(..., report_error_detected)
pci_walk_bus(..., cb=report_error_detected, ...)
down_read(&pci_bus_sem) # acquire pci_bus_sem
report_error_detected(dev) # cb()
device_lock(dev) # deadlock here
Previously, the bus->devices and bus->slots list were protected by
pci_bus_sem. In pci_create_slot(), we held it for writing so we could
add to the bus->slots list.
Add a new local pci_slot_mutex to protect bus->slots. Hold pci_bus_sem for
reading while searching the bus->devices list.
[bhelgaas: changelog]
Link: http://lkml.kernel.org/r/CAA93t1qpPqbih+UB0McA_d_+2rVaNkXsinAUxYzK9+JXSS+L-g@mail.gmail.com
Reported-by: Rajat Jain <rajatja@google.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Summary of http://lkml.org/lkml/2014/3/14/363 :
Ted: module_param(queue_depth, int, 444)
Joe: 0444!
Rusty: User perms >= group perms >= other perms?
Joe: CLASS_ATTR, DEVICE_ATTR, SENSOR_ATTR and SENSOR_ATTR_2?
Side effect of stricter permissions means removing the unnecessary
S_IFREG from several callers.
Note that the BUILD_BUG_ON_ZERO((perm) & 2) test was removed: a fair
number of drivers fail this test, so that will be the debate for a
future patch.
Suggested-by: Joe Perches <joe@perches.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com> for drivers/pci/slot.c
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
My philosophy is unused code is dead code. And dead code is subject to bit
rot and is a likely source of bugs. Use it or lose it.
This reverts part of f46753c5e3 ("PCI: introduce pci_slot") and
d25b7c8d6b ("PCI: rename pci_update_slot_number to pci_renumber_slot"),
removing this interface:
pci_renumber_slot()
[bhelgaas: split to separate patch, add historical link from Alex]
Link: http://lkml.kernel.org/r/20081009043140.8678.44164.stgit@bob.kio
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Alex Chiang <achiang@canonical.com>
Fix whitespace, capitalization, and spelling errors. No functional change.
I know "busses" is not an error, but "buses" was more common, so I used it
consistently.
Signed-off-by: Marta Rybczynska <rybczynska@gmail.com> (pci_reset_bridge_secondary_bus())
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
These places capture return values to avoid "must_check" warnings,
but we didn't *do* anything with the return values, which causes
"set but not used" warnings. We might as well do something instead
of just trying to evade the "must_check" warnings.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
These were getting module.h implicitly from device.h but we want
to clean that up, so we fix it here to avoid things like:
pci/slot.c: In function ‘pci_hp_create_module_link’:
pci/slot.c:383: error: ‘module_kset’ undeclared (first use in this function)
Similarly, rpadlpar_core.c is modular, so add module.h to its includes.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
This reverts commit 75568f8094.
Since they're just a convenience anyway, remove these symlinks since
they're causing duplicate filename errors in the wild.
Acked-by: Alex Chiang <achiang@canonical.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Create convenience symlinks in sysfs, linking slots to device
functions, and vice versa. These links make it easier for users to
figure out which devices actually live in what slots.
For example:
sapphire:/sys/bus/pci/slots # ls
1 10 2 3 4 5 6 7 8 9
sapphire:/sys/bus/pci/slots # ls -l 3
total 0
-r--r--r-- 1 root root 65536 Aug 18 14:10 address
lrwxrwxrwx 1 root root 0 Aug 18 14:10 function0 ->
../../../../devices/pci0000:23/0000:23:01.0
lrwxrwxrwx 1 root root 0 Aug 18 14:10 function1 ->
../../../../devices/pci0000:23/0000:23:01.1
sapphire:/sys/bus/pci/slots # ls -l 3/function0/slot
lrwxrwxrwx 1 root root 0 Aug 18 14:13 3/function0/slot ->
../../../bus/pci/slots/3
The original form of this patch was written by Matthew Wilcox,
and was enhanced to include links from the sysfs slots/ directory
pointing back at the device functions.
Cc: willy@linux.intel.com
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Constify struct sysfs_ops.
This is part of the ops structure constification
effort started by Arjan van de Ven et al.
Benefits of this constification:
* prevents modification of data that is shared
(referenced) by many other structure instances
at runtime
* detects/prevents accidental (but not intentional)
modification attempts on archs that enforce
read-only kernel data at runtime
* potentially better optimized code as the compiler
can assume that the const data cannot be changed
* the compiler/linker move const data into .rodata
and therefore exclude them from false sharing
Signed-off-by: Emese Revfy <re.emese@gmail.com>
Acked-by: David Teigland <teigland@redhat.com>
Acked-by: Matt Domsch <Matt_Domsch@dell.com>
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Acked-by: Hans J. Koch <hjk@linutronix.de>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Take advantage of some gaps in the table to fit in support for AGP speeds.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Move the max_bus_speed and cur_bus_speed into the pci_bus. Expose the
values through the PCI slot driver instead of the hotplug slot driver.
Update all the hotplug drivers to use the pci_bus instead of their own
data structures.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Create symbolic link to hotplug driver module in the PCI slot
directory (/sys/bus/pci/slots/<SLOT#>). In the past, we need to load
hotplug drivers one by one to identify the hotplug driver that handles
the slot, and it was very inconvenient especially for trouble shooting.
With this change, we can easily identify the hotplug driver.
Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Reviewed-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Add drivers/pci/*.c source files to DocBook/kernel-api.tmpl
and update those pci/*.c source files that need kernel-doc fixes.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Convert usages of pr_debug to dev_dbg and add physical slot name.
Note that we use dev_dbg on the struct pci_bus and still manually
print out the PCI slot number (instead of calling dev_dbg on a
pci_dev) because a struct pci_bus with empty physical slots will
not have any pci_devs.
Reviewed-by: Andrew Patterson <andrew.patterson@hp.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
In pci_create_slot(), the local variable 'slot_name' is allocated by
make_slot_name(), but never freed. We never use it after passing it to
the kobject core, so we should free it upon function exit.
Cc: stable@kernel.org
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
In preparation for cleaning up the various hotplug drivers
such that they don't have to manage their own 'name' parameters
anymore, we provide the following convenience functions:
pci_slot_name()
hotplug_slot_name()
These helpers will be used by individual hotplug drivers.
Cc: kristen.c.accardi@intel.com
Cc: matthew@wil.cx
Acked-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Prevent callers of pci_create_slot() from registering slots with
duplicate names. This condition occurs most often when PCI hotplug
drivers are loaded on platforms with broken firmware that assigns
identical names to multiple slots.
We now rename these duplicate slots on behalf of the user.
If firmware assigns the name N to multiple slots, then:
The first registered slot is assigned N
The second registered slot is assigned N-1
The third registered slot is assigned N-2
etc.
This is the permanent fix mentioned in earlier commits d6a9e9b4 and
167e782e (shpchp/pciehp: Rename duplicate slot name...).
We take advantage of the new 'hotplug' parameter in pci_create_slot()
to prevent a slot create/rename race between hotplug drivers and
detection drivers.
Scenario A:
hotplug driver detection driver
-------------- ----------------
pci_create_slot(hotplug=set)
pci_create_slot(hotplug=NULL)
The hotplug driver creates the slot with its desired name, and then
releases the semaphore. Now, the detection driver tries to create
the same slot, but it already exists. We don't care about renaming,
so return the existing slot.
Scenario B:
hotplug driver detection driver
-------------- ----------------
pci_create_slot(hotplug=NULL)
pci_create_slot(hotplug=set)
The detection driver creates the slot with name "X". Then the hotplug
driver tries to create the same slot, but wants the name "Y" instead.
We detect that we're trying to create the same slot and that we also
want a rename, so rename the slot to "Y" and return.
Scenario C:
hotplug driver hotplug driver
-------------- ----------------
pci_create_slot(hotplug=set)
pci_create_slot(hotplug=set)
Two separate hotplug drivers are attempting to claim the slot and
are passing valid hotplug_slot args to pci_create_slot(). We detect
that the slot already has a ->hotplug callback, prevent a rename,
and return -EBUSY.
Cc: kristen.c.accardi@intel.com
Cc: matthew@wil.cx
Acked-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Slot detection drivers can co-exist with hotplug drivers. The names
of the detected/claimed slots may be different depending on module
load order.
For legacy reasons, we need to allow hotplug drivers to override
the slot name if a detection driver is loaded first (and they find
the same slots).
Creating and overriding slot names should be an atomic operation,
otherwise you get a locking nightmare as various drivers race to
call pci_create_slot().
pci_create_slot() is already serialized by grabbing the pci_bus_sem.
We update the API and add a 'hotplug' param, which is:
set if the caller is a hotplug driver
NULL if the caller is a detection driver
pci_create_slot() does not actually use the 'hotplug' parameter in this
patch. A later patch will add the logic that uses it.
Cc: kristen.c.accardi@intel.com
Cc: matthew@wil.cx
Acked-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
The GPL exported symbol pci_update_slot_number has been renamed to
pci_renumber_slot. Some of the safety checks were unnecessary and
were removed.
Cc: kristen.c.accardi@intel.com
Cc: matthew@wil.cx
Acked-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
The introduction of struct pci_slot (f46753c5e3)
added a struct pci_slot pointer to struct pci_dev, but we forgot to
associate the two.
Connect the two structs together; the interesting portions of the object
lifetimes are:
- when a new pci_slot is created, connect it to the appropriate
pci_dev's. A single pci_slot may be associated with multiple
pci_dev's, e.g. any multi-function PCI device.
- when a pci_slot is released, look for all the pci_dev's it was
associated with, and set their pci_slot pointers to NULL
- when a pci_dev is created, look for slots to associate with.
Note -- when a pci_dev is released, we don't need to do any bookkeeping,
since pci_slot's do not have pointers to pci_dev's.
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Currently, /sys/bus/pci/slots/ only exposes hotplug attributes when a
hotplug driver is loaded, but PCI slots have attributes such as address,
speed, width, etc. that are not related to hotplug at all.
Introduce pci_slot as the primary data structure and kobject model.
Hotplug attributes described in hotplug_slot become a secondary
structure associated with the pci_slot.
This patch only creates the infrastructure that allows the separation of
PCI slot attributes and hotplug attributes. In this patch, the PCI
hotplug core remains the only user of this infrastructure, and thus,
/sys/bus/pci/slots/ will still only become populated when a hotplug
driver is loaded.
A later patch in this series will add a second user of this new
infrastructure and demonstrate splitting the task of exposing pci_slot
attributes from hotplug_slot attributes.
- Make pci_slot the primary sysfs entity. hotplug_slot becomes a
subsidiary structure.
o pci_create_slot() creates and registers a slot with the PCI core
o pci_slot_add_hotplug() gives it hotplug capability
- Change the prototype of pci_hp_register() to take the bus and
slot number (on parent bus) as parameters.
- Remove all the ->get_address methods since this functionality is
now handled by pci_slot directly.
[achiang@hp.com: rpaphp-correctly-pci_hp_register-for-empty-pci-slots]
Tested-by: Badari Pulavarty <pbadari@us.ibm.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: make headers_check happy]
[akpm@linux-foundation.org: nuther build fix]
[akpm@linux-foundation.org: fix typo in #include]
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Matthew Wilcox <matthew@wil.cx>
Cc: Greg KH <greg@kroah.com>
Cc: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Cc: Len Brown <lenb@kernel.org>
Acked-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
