When a hotplug driver calls pci_hp_register(), all steps necessary for
registration are carried out in one go, including creation of a kobject
and addition to sysfs. That's a problem for pciehp once it's converted
to enable/disable the slot exclusively from the IRQ thread: The thread
needs to be spawned after creation of the kobject (because it uses the
kobject's name), but before addition to sysfs (because it will handle
enable/disable requests submitted via sysfs).
pci_hp_deregister() does offer a ->release callback that's invoked
after deletion from sysfs and before destruction of the kobject. But
because pci_hp_register() doesn't offer a counterpart, hotplug drivers'
->probe and ->remove code becomes asymmetric, which is error prone
as recently discovered use-after-free bugs in pciehp's ->remove hook
have shown.
In a sense, this appears to be a case of the midlayer antipattern:
"The core thesis of the "midlayer mistake" is that midlayers are
bad and should not exist. That common functionality which it is
so tempting to put in a midlayer should instead be provided as
library routines which can [be] used, augmented, or ignored by
each bottom level driver independently. Thus every subsystem
that supports multiple implementations (or drivers) should
provide a very thin top layer which calls directly into the
bottom layer drivers, and a rich library of support code that
eases the implementation of those drivers. This library is
available to, but not forced upon, those drivers."
-- Neil Brown (2009), https://lwn.net/Articles/336262/
The presence of midlayer traits in the PCI hotplug core might be ascribed
to its age: When it was introduced in February 2002, the blessings of a
library approach might not have been well known:
https://git.kernel.org/tglx/history/c/a8a2069f432c
For comparison, the driver core does offer split functions for creating
a kobject (device_initialize()) and addition to sysfs (device_add()) as
an alternative to carrying out everything at once (device_register()).
This was introduced in October 2002:
https://git.kernel.org/tglx/history/c/8b290eb19962
The odd ->release callback in the PCI hotplug core was added in 2003:
https://git.kernel.org/tglx/history/c/69f8d663b595
Clearly, a library approach would not force every hotplug driver to
implement a ->release callback, but rather allow the driver to remove
the sysfs files, release its data structures and finally destroy the
kobject. Alternatively, a driver may choose to remove everything with
pci_hp_deregister(), then release its data structures.
To this end, offer drivers pci_hp_initialize() and pci_hp_add() as a
split-up version of pci_hp_register(). Likewise, offer pci_hp_del()
and pci_hp_destroy() as a split-up version of pci_hp_deregister().
Eliminate the ->release callback and move its code into each driver's
teardown routine.
Declare pci_hp_deregister() void, in keeping with the usual kernel
pattern that enablement can fail, but disablement cannot. It only
returned an error if the caller passed in a NULL pointer or a slot which
has never or is no longer registered or is sharing its name with another
slot. Those would be bugs, so WARN about them. Few hotplug drivers
actually checked the return value and those that did only printed a
useless error message to dmesg. Remove that.
For most drivers the conversion was straightforward since it doesn't
matter whether the code in the ->release callback is executed before or
after destruction of the kobject. But in the case of ibmphp, it was
unclear to me whether setting slot_cur->ctrl and slot_cur->bus_on to
NULL needs to happen before the kobject is destroyed, so I erred on
the side of caution and ensured that the order stays the same. Another
nontrivial case is pnv_php, I've found the list and kref logic difficult
to understand, however my impression was that it is safe to delete the
list element and drop the references until after the kobject is
destroyed.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> # drivers/platform/x86
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
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: 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>
Cc: Andy Shevchenko <andy@infradead.org>
The device node iterators perform an of_node_get() on each iteration, so a
jump out of the loop requires an of_node_put().
The semantic patch that fixes this problem is as follows
(http://coccinelle.lip6.fr):
// <smpl>
@@
expression root,e;
local idexpression child;
iterator name for_each_child_of_node;
@@
for_each_child_of_node(root, child) {
... when != of_node_put(child)
when != e = child
+ of_node_put(child);
? break;
...
}
... when != child
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
In pnv_php_unregister_one(), pnv_php_put_slot() might kfree
php_slot structure. But there is pci_hp_deregister() after
that with php_slot reference.
This patch moves pnv_php_put_slot() to the end of function.
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* 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
Add SPDX GPL-2.0+ to all PCI files that specified the GPL and allowed
either GPL version 2 or any later version.
Remove the boilerplate GPL version 2 or later language, relying on the
assertion in b24413180f ("License cleanup: add SPDX GPL-2.0 license
identifier to files with no license") that the SPDX identifier may be used
instead of the full boilerplate text.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add PCI-specific dev_printk() wrappers and use them to simplify the code
slightly. No functional change intended.
Signed-off-by: Frederick Lawler <fred@fredlawl.com>
[bhelgaas: squash into one patch]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Per ebfdc40969 ("checkpatch: attempt to find unnecessary 'out of memory'
messages"), when a memory allocation fails, the memory subsystem emits
generic "out of memory" messages (see slab_out_of_memory() for some of this
logging). Therefore, additional error messages in the caller don't add
much value.
Remove messages that merely report "out of memory".
This preserves some messages that report additional information, e.g.,
allocation failures that mean we drop hotplug events.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
[bhelgaas: changelog, squash patches, make similar changes to acpiphp,
cpqphp, ibmphp, keep warning when dropping hotplug event]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Now that we have a custom printf format specifier, convert users of
full_name() to use %pOF instead. This is preparation for removing storing
of the full path string for each node.
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Highlights include:
- An update of the disassembly code used by xmon to the latest versions in
binutils. We've received permission from all the authors of the relevant
binutils changes to relicense their changes to the relevant files from GPLv3
to GPLv2, for inclusion in Linux. Thanks to Peter Bergner for doing the leg
work to get permission from everyone.
- Addition of the "architected" Power9 CPU table entry, allowing us to boot
in Power9 architected mode under a hypervisor.
- Updates to the Power9 PMU code.
- Implementation of clear_bit_unlock_is_negative_byte() to optimise
unlock_page().
- Freescale updates from Scott: "Highlights include 8xx breakpoints and perf,
t1042rdb display support, and board updates."
Thanks to:
Al Viro, Andrew Donnellan, Aneesh Kumar K.V, Balbir Singh, Douglas Miller,
Frédéric Weisbecker, Gavin Shan, Madhavan Srinivasan, Michael Roth, Nathan
Fontenot, Naveen N. Rao, Nicholas Piggin, Peter Bergner, Paul E. McKenney,
Rashmica Gupta, Russell Currey, Sahil Mehta, Stewart Smith.
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Merge tag 'powerpc-4.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull more powerpc updates from Michael Ellerman:
"Highlights include:
- an update of the disassembly code used by xmon to the latest
versions in binutils. We've received permission from all the
authors of the relevant binutils changes to relicense their changes
to the relevant files from GPLv3 to GPLv2, for inclusion in Linux.
Thanks to Peter Bergner for doing the leg work to get permission
from everyone.
- addition of the "architected" Power9 CPU table entry, allowing us
to boot in Power9 architected mode under a hypervisor.
- updates to the Power9 PMU code.
- implementation of clear_bit_unlock_is_negative_byte() to optimise
unlock_page().
- Freescale updates from Scott: "Highlights include 8xx breakpoints
and perf, t1042rdb display support, and board updates."
Thanks to:
Al Viro, Andrew Donnellan, Aneesh Kumar K.V, Balbir Singh, Douglas
Miller, Frédéric Weisbecker, Gavin Shan, Madhavan Srinivasan,
Michael Roth, Nathan Fontenot, Naveen N. Rao, Nicholas Piggin, Peter
Bergner, Paul E. McKenney, Rashmica Gupta, Russell Currey, Sahil
Mehta, Stewart Smith"
* tag 'powerpc-4.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (48 commits)
powerpc: Remove leftover cputime_to_nsecs call causing build error
powerpc/mm/hash: Always clear UPRT and Host Radix bits when setting up CPU
powerpc/optprobes: Fix TOC handling in optprobes trampoline
powerpc/pseries: Advertise Hot Plug Event support to firmware
cxl: fix nested locking hang during EEH hotplug
powerpc/xmon: Dump memory in CPU endian format
powerpc/pseries: Revert 'Auto-online hotplugged memory'
powerpc/powernv: Make PCI non-optional
powerpc/64: Implement clear_bit_unlock_is_negative_byte()
powerpc/powernv: Remove unused variable in pnv_pci_sriov_disable()
powerpc/kernel: Remove error message in pcibios_setup_phb_resources()
powerpc/mm: Fix typo in set_pte_at()
pci/hotplug/pnv-php: Disable MSI and PCI device properly
pci/hotplug/pnv-php: Disable surprise hotplug capability on conflicts
pci/hotplug/pnv-php: Remove WARN_ON() in pnv_php_put_slot()
powerpc: Add POWER9 architected mode to cputable
powerpc/perf: use is_kernel_addr macro in perf_get_misc_flags()
powerpc/perf: Avoid FAB_*_MATCH checks for power9
powerpc/perf: Add restrictions to PMC5 in power9 DD1
powerpc/perf: Use Instruction Counter value
...
pnv_php_disable_irq() can be called in two paths: Bailing path in
pnv_php_enable_irq() or releasing slot. The MSI (or MSIx) interrupts
is disabled unconditionally in pnv_php_disable_irq(). It's wrong
because that might be enabled by drivers other than pnv-php.
This disables MSI (or MSIx) interrupts and the PCI device only if
it was enabled by pnv-php. In the error path of pnv_php_enable_irq(),
we rely on the newly added parameter @disable_device. In the path
of releasing slot, @pnv_php->irq is checked.
Cc: <stable@vger.kernel.org> # v4.9+
Fixes: 360aebd85a ("drivers/pci/hotplug: Support surprise hotplug in powernv driver")
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The root port or PCIe switch downstream port might have been associated
with driver other than pnv-php. The MSI or MSIx might also have been
enabled by that driver (e.g. pcieport_drv). Attempt to enable MSI incurs
below backtrace:
PowerPC PowerNV PCI Hotplug Driver version: 0.1
------------[ cut here ]------------
WARNING: CPU: 19 PID: 1004 at drivers/pci/msi.c:1071 \
__pci_enable_msi_range+0x84/0x4e0
NIP [c000000000665c34] __pci_enable_msi_range+0x84/0x4e0
LR [c000000000665c24] __pci_enable_msi_range+0x74/0x4e0
Call Trace:
[c000000384d67600] [c000000000665c24] __pci_enable_msi_range+0x74/0x4e0
[c000000384d676e0] [d00000000aa31b04] pnv_php_register+0x564/0x5a0 [pnv_php]
[c000000384d677c0] [d00000000aa31658] pnv_php_register+0xb8/0x5a0 [pnv_php]
[c000000384d678a0] [d00000000aa31658] pnv_php_register+0xb8/0x5a0 [pnv_php]
[c000000384d67980] [d00000000aa31dfc] pnv_php_init+0x60/0x98 [pnv_php]
[c000000384d679f0] [c00000000000cfdc] do_one_initcall+0x6c/0x1d0
[c000000384d67ab0] [c000000000b92354] do_init_module+0x94/0x254
[c000000384d67b40] [c00000000019719c] load_module+0x258c/0x2c60
[c000000384d67d30] [c000000000197bb0] SyS_finit_module+0xf0/0x170
[c000000384d67e30] [c00000000000b184] system_call+0x38/0xe0
This fixes the issue by skipping enabling the surprise hotplug
capability if the MSI or MSIx on the PCI slot's upstream port has
been enabled by other driver.
Cc: <stable@vger.kernel.org> # v4.9+
Fixes: 360aebd85a ("drivers/pci/hotplug: Support surprise hotplug in powernv driver")
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Tested-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
We're supporting surprise hotplug on PCI slots behind root port
or PCIe switch downstream ports, which don't claim the capability
in hardware register (offset: PCIe cap + PCI_EXP_SLTCAP). PEX8718
is one of the examples. For those PCI slots, the PDC (Presence
Detection Change) event isn't reliable and the underly (skiboot)
firmware has best judgement.
This masks the PDC event when skiboot requests by "ibm,slot-broken-pdc"
property in PCI slot's device-tree node.
Reported-by: Hank Chang <hankmax0000@gmail.com>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Tested-by: Willie Liauw <williel@supermicro.com.tw>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In PowerNV PCI hotplug driver, the initial PCI slot's state is set
to PNV_PHP_STATE_POPULATED if no PCI devices are connected to the
slot. The PCI devices that are hot added to the slot won't be probed
and populated because of the check in pnv_php_enable():
/* Check if the slot has been configured */
if (php_slot->state != PNV_PHP_STATE_REGISTERED)
return 0;
This fixes the issue by leaving the slot in PNV_PHP_STATE_REGISTERED
state initially if nothing is connected to the slot.
Fixes: 360aebd85a ("drivers/pci/hotplug: Support surprise hotplug in powernv driver")
Cc: stable@vger.kernel.org #v4.9+
Reported-by: Hank Chang <hankmax0000@gmail.com>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Tested-by: Willie Liauw <williel@supermicro.com.tw>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The surprise hotplug is driven by interrupt in PowerNV PCI hotplug
driver. In the interrupt handler, pnv_php_interrupt(), we bail when
pnv_pci_get_presence_state() returns zero wrongly. It causes the
presence change event is always ignored incorrectly.
This fixes the issue by bailing on error (non-zero value) returned
from pnv_pci_get_presence_state().
Fixes: 360aebd85a ("drivers/pci/hotplug: Support surprise hotplug in powernv driver")
Cc: stable@vger.kernel.org #v4.9+
Reported-by: Hank Chang <hankmax0000@gmail.com>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Tested-by: Willie Liauw <williel@supermicro.com.tw>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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>
This replaces of_get_property() with of_property_read_u32() or
of_property_read_string() so that we needn't consider the endian
issue, the returned value always is in CPU-endian.
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
[mpe: Fold in the change to the "ibm,slot-surprise-pluggable" case]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This supports PCI surprise hotplug. The design is highlighted as
below:
* The PCI slot's surprise hotplug capability is exposed through
device node property "ibm,slot-surprise-pluggable", meaning
PCI surprise hotplug will be disabled if skiboot doesn't support
it yet.
* The interrupt because of presence or link state change is raised
on surprise hotplug event. One event is allocated and queued to
the PCI slot for workqueue to pick it up and process in serialized
fashion. The code flow for surprise hotplug is same to that for
managed hotplug except: the affected PEs are put into frozen state
to avoid unexpected EEH error reporting in surprise hot remove path.
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This removes likely() and unlikely() in pnv_php.c as the code isn't
running in hot path. Those macros to affect CPU's branch stream don't
help a lot for performance. I used them to identify the cases are
likely or unlikely to happen. No logical changes introduced.
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
When calling pnv_php_set_slot_power_state() with state ==
OPAL_PCI_SLOT_OFFLINE, remove devices from the device tree as if we're
dealing with OPAL_PCI_SLOT_POWER_OFF.
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>
Cc: linux-pci@vger.kernel.org
Cc: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Acked-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The cxl driver will use infrastructure from pnv_php to handle device tree
updates when switching bi-modal CAPI cards into CAPI mode.
To enable this, export pnv_php_find_slot() and
pnv_php_set_slot_power_state(), and add corresponding declarations, as well
as the definition of struct pnv_php_slot, to asm/pnv-pci.h.
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>
Cc: linux-pci@vger.kernel.org
Cc: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Acked-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This adds standalone driver to support PCI hotplug for PowerPC PowerNV
platform that runs on top of skiboot firmware. The firmware identifies
hotpluggable slots and marked their device tree node with proper
"ibm,slot-pluggable" and "ibm,reset-by-firmware". The driver scans
device tree nodes to create/register PCI hotplug slot accordingly.
The PCI slots are organized in fashion of tree, which means one
PCI slot might have parent PCI slot and parent PCI slot possibly
contains multiple child PCI slots. At the plugging time, the parent
PCI slot is populated before its children. The child PCI slots are
removed before their parent PCI slot can be removed from the system.
If the skiboot firmware doesn't support slot status retrieval, the PCI
slot device node shouldn't have property "ibm,reset-by-firmware". In
that case, none of valid PCI slots will be detected from device tree.
The skiboot firmware doesn't export the capability to access attention
LEDs yet and it's something for TBD.
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Lukas Wunner