Revert "PCI: acpiphp: Reassign resources on bridge if necessary"

commit 5df12742b7e3aae2594a30a9d14d5d6e9e7699f4 upstream.

This reverts commit 40613da52b13fb21c5566f10b287e0ca8c12c4e9 and the
subse

Revert "PCI: acpiphp: Reassign resources on bridge if necessary"

commit 5df12742b7e3aae2594a30a9d14d5d6e9e7699f4 upstream.

This reverts commit 40613da52b13fb21c5566f10b287e0ca8c12c4e9 and the
subsequent fix to it:

cc22522fd55e ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus")

40613da52b13 fixed a problem where hot-adding a device with large BARs
failed if the bridge windows programmed by firmware were not large enough.

cc22522fd55e ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources()
only for non-root bus") fixed a problem with 40613da52b13: an ACPI hot-add
of a device on a PCI root bus (common in the virt world) or firmware
sending ACPI Bus Check to non-existent Root Ports (e.g., on Dell Inspiron
7352/0W6WV0) caused a NULL pointer dereference and suspend/resume hangs.

Unfortunately the combination of 40613da52b13 and cc22522fd55e caused other
problems:

- Fiona reported that hot-add of SCSI disks in QEMU virtual machine fails
sometimes.

- Dongli reported a similar problem with hot-add of SCSI disks.

- Jonathan reported a console freeze during boot on bare metal due to an
error in radeon GPU initialization.

Revert both patches to avoid adding these problems. This means we will
again see the problems with hot-adding devices with large BARs and the NULL
pointer dereferences and suspend/resume issues that 40613da52b13 and
cc22522fd55e were intended to fix.

Fixes: 40613da52b13 ("PCI: acpiphp: Reassign resources on bridge if necessary")
Fixes: cc22522fd55e ("PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus")
Reported-by: Fiona Ebner <f.ebner@proxmox.com>
Closes: https://lore.kernel.org/r/9eb669c0-d8f2-431d-a700-6da13053ae54@proxmox.com
Reported-by: Dongli Zhang <dongli.zhang@oracle.com>
Closes: https://lore.kernel.org/r/3c4a446a-b167-11b8-f36f-d3c1b49b42e9@oracle.com
Reported-by: Jonathan Woithe <jwoithe@just42.net>
Closes: https://lore.kernel.org/r/ZXpaNCLiDM+Kv38H@marvin.atrad.com.au
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Igor Mammedov <imammedo@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus

40613da52b13 ("PCI: acpiphp: Reassign resources on bridge if necessary")
changed acpiphp hotplug to use pci_assign_un

PCI: acpiphp: Use pci_assign_unassigned_bridge_resources() only for non-root bus

40613da52b13 ("PCI: acpiphp: Reassign resources on bridge if necessary")
changed acpiphp hotplug to use pci_assign_unassigned_bridge_resources()
which depends on bridge being available, however enable_slot() can be
called without bridge associated:

1. Legitimate case of hotplug on root bus (widely used in virt world)

2. A (misbehaving) firmware, that sends ACPI Bus Check notifications to
non existing root ports (Dell Inspiron 7352/0W6WV0), which end up at
enable_slot(..., bridge = 0) where bus has no bridge assigned to it.
acpihp doesn't know that it's a bridge, and bus specific 'PCI
subsystem' can't augment ACPI context with bridge information since
the PCI device to get this data from is/was not available.

Issue is easy to reproduce with QEMU's 'pc' machine, which supports PCI
hotplug on hostbridge slots. To reproduce, boot kernel at commit
40613da52b13 in VM started with following CLI (assuming guest root fs is
installed on sda1 partition):

# qemu-system-x86_64 -M pc -m 1G -enable-kvm -cpu host \
-monitor stdio -serial file:serial.log \
-kernel arch/x86/boot/bzImage \
-append "root=/dev/sda1 console=ttyS0" \
guest_disk.img

Once guest OS is fully booted at qemu prompt:

(qemu) device_add e1000

(check serial.log) it will cause NULL pointer dereference at:

void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge)
{
struct pci_bus *parent = bridge->subordinate;

BUG: kernel NULL pointer dereference, address: 0000000000000018

? pci_assign_unassigned_bridge_resources+0x1f/0x260
enable_slot+0x21f/0x3e0
acpiphp_hotplug_notify+0x13d/0x260
acpi_device_hotplug+0xbc/0x540
acpi_hotplug_work_fn+0x15/0x20
process_one_work+0x1f7/0x370
worker_thread+0x45/0x3b0

The issue was discovered on Dell Inspiron 7352/0W6WV0 laptop with following
sequence:

1. Suspend to RAM
2. Wake up with the same backtrace being observed:
3. 2nd suspend to RAM attempt makes laptop freeze

Fix it by using __pci_bus_assign_resources() instead of
pci_assign_unassigned_bridge_resources() as we used to do, but only in case
when bus doesn't have a bridge associated (to cover for the case of ACPI
event on hostbridge or non existing root port).

That lets us keep hotplug on root bus working like it used to and at the
same time keeps resource reassignment usable on root ports (and other 1st
level bridges) that was fixed by 40613da52b13.

Fixes: 40613da52b13 ("PCI: acpiphp: Reassign resources on bridge if necessary")
Link: https://lore.kernel.org/r/20230726123518.2361181-2-imammedo@redhat.com
Reported-by: Woody Suwalski <terraluna977@gmail.com>
Tested-by: Woody Suwalski <terraluna977@gmail.com>
Tested-by: Michal Koutný <mkoutny@suse.com>
Link: https://lore.kernel.org/r/11fc981c-af49-ce64-6b43-3e282728bd1a@gmail.com
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>

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PCI: acpiphp: Reassign resources on bridge if necessary

When using ACPI PCI hotplug, hotplugging a device with large BARs may fail
if bridge windows programmed by firmware are not large enough.

Rep

PCI: acpiphp: Reassign resources on bridge if necessary

When using ACPI PCI hotplug, hotplugging a device with large BARs may fail
if bridge windows programmed by firmware are not large enough.

Reproducer:
$ qemu-kvm -monitor stdio -M q35 -m 4G \
-global ICH9-LPC.acpi-pci-hotplug-with-bridge-support=on \
-device id=rp1,pcie-root-port,bus=pcie.0,chassis=4 \
disk_image

wait till linux guest boots, then hotplug device:
(qemu) device_add qxl,bus=rp1

hotplug on guest side fails with:
pci 0000:01:00.0: [1b36:0100] type 00 class 0x038000
pci 0000:01:00.0: reg 0x10: [mem 0x00000000-0x03ffffff]
pci 0000:01:00.0: reg 0x14: [mem 0x00000000-0x03ffffff]
pci 0000:01:00.0: reg 0x18: [mem 0x00000000-0x00001fff]
pci 0000:01:00.0: reg 0x1c: [io 0x0000-0x001f]
pci 0000:01:00.0: BAR 0: no space for [mem size 0x04000000]
pci 0000:01:00.0: BAR 0: failed to assign [mem size 0x04000000]
pci 0000:01:00.0: BAR 1: no space for [mem size 0x04000000]
pci 0000:01:00.0: BAR 1: failed to assign [mem size 0x04000000]
pci 0000:01:00.0: BAR 2: assigned [mem 0xfe800000-0xfe801fff]
pci 0000:01:00.0: BAR 3: assigned [io 0x1000-0x101f]
qxl 0000:01:00.0: enabling device (0000 -> 0003)
Unable to create vram_mapping
qxl: probe of 0000:01:00.0 failed with error -12

However when using native PCIe hotplug
'-global ICH9-LPC.acpi-pci-hotplug-with-bridge-support=off'
it works fine, since kernel attempts to reassign unused resources.

Use the same machinery as native PCIe hotplug to (re)assign resources.

Link: https://lore.kernel.org/r/20230424191557.2464760-1-imammedo@redhat.com
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Cc: stable@vger.kernel.org

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PCI: acpiphp: Avoid setting is_hotplug_bridge for PCIe Upstream Ports

It is reported that on some systems pciehp binds to an Upstream Port and
attempts to operate it which causes devices below the P

PCI: acpiphp: Avoid setting is_hotplug_bridge for PCIe Upstream Ports

It is reported that on some systems pciehp binds to an Upstream Port and
attempts to operate it which causes devices below the Port to disappear
from the bus.

This happens because acpiphp sets dev->is_hotplug_bridge for that Port
(after receiving a Device Check notification on it from the platform
firmware via ACPI) during the enumeration of PCI devices.

get_port_device_capability() sees that dev->is_hotplug_bridge is set and
adds PCIE_PORT_SERVICE_HP to Port services, which allows pciehp to bind to
the Port in question.

Even though this particular problem can be addressed by making the
portdrv_core checks more robust, it also causes power management to work
differently on the affected systems which generally is not desirable (PCIe
Ports with dev->is_hotplug_bridge set have to pass additional tests to be
allowed to go into the D3hot/cold power states which affects runtime PM of
devices below these Ports).

For this reason, amend check_hotplug_bridge() with a PCIe type check to
prevent it from setting dev->is_hotplug_bridge for Upstream Ports.

Suggested-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/2262230.ElGaqSPkdT@kreacher
Reported-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Tested-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>

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PCI/ACPI: Replace acpi_bus_get_device() with acpi_fetch_acpi_dev()

Replace acpi_bus_get_device() that is going to be dropped with
acpi_fetch_acpi_dev().

No intentional functional impact.

Link: htt

PCI/ACPI: Replace acpi_bus_get_device() with acpi_fetch_acpi_dev()

Replace acpi_bus_get_device() that is going to be dropped with
acpi_fetch_acpi_dev().

No intentional functional impact.

Link: https://lore.kernel.org/r/11930209.O9o76ZdvQC@kreacher
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>

show more ...

PCI: Correct misspelled and remove duplicated words

Correct a number of misspelled words and remove any words that were
duplicated in the PCI tree. No change to functionality intended.

Link: https

PCI: Correct misspelled and remove duplicated words

Correct a number of misspelled words and remove any words that were
duplicated in the PCI tree. No change to functionality intended.

Link: https://lore.kernel.org/r/20211006233827.147328-1-kw@linux.com
Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

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ACPI / hotplug / PCI: Fix reference count leak in enable_slot()

In enable_slot(), if pci_get_slot() returns NULL, we clear the SLOT_ENABLED
flag. When pci_get_slot() finds a device, it increments th

ACPI / hotplug / PCI: Fix reference count leak in enable_slot()

In enable_slot(), if pci_get_slot() returns NULL, we clear the SLOT_ENABLED
flag. When pci_get_slot() finds a device, it increments the device's
reference count. In this case, we did not call pci_dev_put() to decrement
the reference count, so the memory of the device (struct pci_dev type) will
eventually leak.

Call pci_dev_put() to decrement its reference count when pci_get_slot()
returns a PCI device.

Link: https://lore.kernel.org/r/b411af88-5049-a1c6-83ac-d104a1f429be@huawei.com
Signed-off-by: Feilong Lin <linfeilong@huawei.com>
Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

show more ...

ACPI / hotplug / PCI: Fix reference count leak in enable_slot()

[ Upstream commit 3bbfd319034ddce59e023837a4aa11439460509b ]

In enable_slot(), if pci_get_slot() returns NULL, we clear the SLOT_ENAB

ACPI / hotplug / PCI: Fix reference count leak in enable_slot()

[ Upstream commit 3bbfd319034ddce59e023837a4aa11439460509b ]

In enable_slot(), if pci_get_slot() returns NULL, we clear the SLOT_ENABLED
flag. When pci_get_slot() finds a device, it increments the device's
reference count. In this case, we did not call pci_dev_put() to decrement
the reference count, so the memory of the device (struct pci_dev type) will
eventually leak.

Call pci_dev_put() to decrement its reference count when pci_get_slot()
returns a PCI device.

Link: https://lore.kernel.org/r/b411af88-5049-a1c6-83ac-d104a1f429be@huawei.com
Signed-off-by: Feilong Lin <linfeilong@huawei.com>
Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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

If context is not NULL in acpiphp_grab_context(), but the
is_going_away flag is set for the device's parent, the reference
count

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

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 <vvs@virtuozzo.com>
Cc: 3.15+ <stable@vger.kernel.org> # 3.15+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

show more ...

ACPI: hotplug: PCI: Use the new acpi_evaluate_reg() helper

Use the new acpi_evaluate_reg() helper in the acpiphp_glue.c code.

Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Andy Shevche

ACPI: hotplug: PCI: Use the new acpi_evaluate_reg() helper

Use the new acpi_evaluate_reg() helper in the acpiphp_glue.c code.

Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

show more ...

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

Valerio and others reported that commit 84c8b58ed3ad ("ACPI / hotplug /
PCI: Don't scan bridges managed by native hotpl

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

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 <passini.valerio@gmail.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: stable@vger.kernel.org

show more ...

Update email address

Redirect some older email addresses that are in the git logs.

Signed-off-by: Matthew Wilcox <willy@infradead.org>

ACPI / hotplug / PCI: Don't scan for non-hotplug bridges if slot is not bridge

HP 6730b laptop has an ethernet NIC connected to one of the PCIe root
ports. The root ports themselves are native PCIe

ACPI / hotplug / PCI: Don't scan for non-hotplug bridges if slot is not bridge

HP 6730b laptop has an ethernet NIC connected to one of the PCIe root
ports. The root ports themselves are native PCIe hotplug capable. Now,
during boot after PCI devices are scanned the BIOS triggers ACPI bus check
directly to the NIC:

ACPI: \_SB_.PCI0.RP06.NIC_: Bus check in hotplug_event()

It is not clear why it is sending bus check but regardless the ACPI hotplug
notify handler calls enable_slot() directly (instead of going through
acpiphp_check_bridge() as there is no bridge), which ends up handling
special case for non-hotplug bridges with native PCIe hotplug. This
results a crash of some kind but the reporter only sees black screen so it
is hard to figure out the exact spot and what actually happens. Based on
a few fix proposals it was tracked to crash somewhere inside
pci_assign_unassigned_bridge_resources().

In any case we should not really be in that special branch at all because
the ACPI notify happened to a slot that is not a PCI bridge (it is just a
regular PCI device).

Fix this so that we only go to that special branch if we are calling
enable_slot() for a bridge (e.g., the ACPI notification was for the
bridge).

Link: https://bugzilla.kernel.org/show_bug.cgi?id=201127
Fixes: 84c8b58ed3ad ("ACPI / hotplug / PCI: Don't scan bridges managed by native hotplug")
Reported-by: Peter Anemone <peter.anemone@gmail.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
CC: stable@vger.kernel.org # v4.18+

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PCI: Fix is_added/is_busmaster race condition

When a PCI device is detected, pdev->is_added is set to 1 and proc and
sysfs entries are created.

When the device is removed, pdev->is_added is checked

PCI: Fix is_added/is_busmaster race condition

When a PCI device is detected, pdev->is_added is set to 1 and proc and
sysfs entries are created.

When the device is removed, pdev->is_added is checked for one and then
device is detached with clearing of proc and sys entries and at end,
pdev->is_added is set to 0.

is_added and is_busmaster are bit fields in pci_dev structure sharing same
memory location.

A strange issue was observed with multiple removal and rescan of a PCIe
NVMe device using sysfs commands where is_added flag was observed as zero
instead of one while removing device and proc,sys entries are not cleared.
This causes issue in later device addition with warning message
"proc_dir_entry" already registered.

Debugging revealed a race condition between the PCI core setting the
is_added bit in pci_bus_add_device() and the NVMe driver reset work-queue
setting the is_busmaster bit in pci_set_master(). As these fields are not
handled atomically, that clears the is_added bit.

Move the is_added bit to a separate private flag variable and use atomic
functions to set and retrieve the device addition state. This avoids the
race because is_added no longer shares a memory location with is_busmaster.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=200283
Signed-off-by: Hari Vyas <hari.vyas@broadcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>

show more ...

ACPI / hotplug / PCI: Drop unnecessary parentheses

Remove unnecessary parentheses.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com

ACPI / hotplug / PCI: Drop unnecessary parentheses

Remove unnecessary parentheses.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

show more ...

ACPI / hotplug / PCI: Mark stale PCI devices disconnected

Following PCIehp mark the unplugged PCI devices disconnected. This makes
sure PCI core code leaves the now missing hardware registers alone

ACPI / hotplug / PCI: Mark stale PCI devices disconnected

Following PCIehp mark the unplugged PCI devices disconnected. This makes
sure PCI core code leaves the now missing hardware registers alone.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

show more ...

ACPI / hotplug / PCI: Don't scan bridges managed by native hotplug

When acpiphp re-enumerates a PCI hierarchy because of an ACPI Notify()
event, we should skip bridges managed by native hotplug (pci

ACPI / hotplug / PCI: Don't scan bridges managed by native hotplug

When acpiphp re-enumerates a PCI hierarchy because of an ACPI Notify()
event, we should skip bridges managed by native hotplug (pciehp or shpchp).
We don't want to scan below a native hotplug bridge until the hotplug
controller generates a hot-add event.

A typical scenario is a Root Port leading to a Thunderbolt host router that
remains powered off until something is connected to it. See [1] for the
lspci details.

1. Before something is connected, only the Root Port exists. It has
PCI_EXP_SLTCAP_HPC set and pciehp is responsible for hotplug:

00:1b.0 Root Port (HotPlug+)

2. When a USB-C or Thunderbolt device is connected, the Switch in the
Thunderbolt host router is powered up, the Root Port signals a hotplug
add event and pciehp enumerates the Switch:

01:00.0 Switch Upstream Port to [bus 02-39]
02:00.0 Switch Downstream Port to [bus 03] (HotPlug-, to NHI)
02:01.0 Switch Downstream Port to [bus 04-38] (HotPlug+, to Thunderbolt connector)
02:02.0 Switch Downstream Port to [bus 39] (HotPlug-, to xHCI)

The 02:00.0 and 02:02.0 Ports lead to Endpoints that are not powered
up yet. The Ports have PCI_EXP_SLTCAP_HPC cleared, so pciehp doesn't
handle hotplug for them and we assign minimal resources to them.

The 02:01.0 Port has PCI_EXP_SLTCAP_HPC set, so pciehp handles native
hotplug events for it.

3. The BIOS powers up the xHCI controller. If a Thunderbolt device was
connected (not just a USB-C device), it also powers up the NHI. Then
it sends an ACPI Notify() to the Root Port, and acpiphp enumerates the
new device(s):

03:00.0 Thunderbolt Host Controller (NHI) Endpoint
39:00.0 xHCI Endpoint

4. If a Thunderbolt device was connected, the host router firmware uses
the NHI to set up Thunderbolt tunnels and triggers a native hotplug
event (via 02:01.0 in this example). Then pciehp enumerates the new
Thunderbolt devices:

04:00.0 Switch Upstream Port to [bus 05-38]
05:01.0 Switch Downstream Port to [bus 06-09] (HotPlug-)
05:04.0 Switch Downstream Port to [bus 0a-38] (HotPlug+)

In this example, 05:01.0 leads to another Switch and some NICs. This
subtree is static, so 05:01.0 doesn't support hotplug and has
PCI_EXP_SLTCAP_HPC cleared.

In step 3, acpiphp previously enumerated everything below the Root Port,
including things below the 02:01.0 Port. We don't want that because pciehp
expects to manage hotplug below that Port, and firmware on the host router
may be in the middle of configuring its Link so it may not be ready yet.

To make this work better with the native PCIe (pciehp) and standard PCI
(shpchp) hotplug drivers, we let them handle all slot management and
resource allocation for hotplug bridges and restrict ACPI hotplug to
non-hotplug bridges.

[1] https://bugzilla.kernel.org/show_bug.cgi?id=199581#c5
Link: https://lkml.kernel.org/r/20180529160155.1738-1-mika.westerberg@linux.intel.com
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
[bhelgaas: changelog, use hotplug_is_native() instead of
dev->is_hotplug_bridge]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

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ACPI / hotplug / PCI: Check presence of slot itself in get_slot_status()

Mike Lothian reported that plugging in a USB-C device does not work
properly in his Dell Alienware system. This system has a

ACPI / hotplug / PCI: Check presence of slot itself in get_slot_status()

Mike Lothian reported that plugging in a USB-C device does not work
properly in his Dell Alienware system. This system has an Intel Alpine
Ridge Thunderbolt controller providing USB-C functionality. In these
systems the USB controller (xHCI) is hotplugged whenever a device is
connected to the port using ACPI-based hotplug.

The ACPI description of the root port in question is as follows:

Device (RP01)
{
Name (_ADR, 0x001C0000)

Device (PXSX)
{
Name (_ADR, 0x02)

Method (_RMV, 0, NotSerialized)
{
// ...
}
}

Here _ADR 0x02 means device 0, function 2 on the bus under root port (RP01)
but that seems to be incorrect because device 0 is the upstream port of the
Alpine Ridge PCIe switch and it has no functions other than 0 (the bridge
itself). When we get ACPI Notify() to the root port resulting from
connecting a USB-C device, Linux tries to read PCI_VENDOR_ID from device 0,
function 2 which of course always returns 0xffffffff because there is no
such function and we never find the device.

In Windows this works fine.

Now, since we get ACPI Notify() to the root port and not to the PXSX device
we should actually start our scan from there as well and not from the
non-existent PXSX device. Fix this by checking presence of the slot itself
(function 0) if we fail to do that otherwise.

While there use pci_bus_read_dev_vendor_id() in get_slot_status(), which is
the recommended way to read Device and Vendor IDs of devices on PCI buses.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=198557
Reported-by: Mike Lothian <mike@fireburn.co.uk>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org

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PCI: Add SPDX GPL-2.0+ to replace GPL v2 or later boilerplate

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

PCI: Add SPDX GPL-2.0+ to replace GPL v2 or later boilerplate

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 b24413180f56 ("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>

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PCI: Remove unnecessary messages for memory allocation failures

Per ebfdc40969f2 ("checkpatch: attempt to find unnecessary 'out of memory'
messages"), when a memory allocation fails, the memory subs

PCI: Remove unnecessary messages for memory allocation failures

Per ebfdc40969f2 ("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>

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PCI: Add for_each_pci_bridge() helper

The following pattern is often used:

list_for_each_entry(dev, &bus->devices, bus_list) {
if (pci_is_bridge(dev)) {
...
}
}

Add a for_each_pc

PCI: Add for_each_pci_bridge() helper

The following pattern is often used:

list_for_each_entry(dev, &bus->devices, bus_list) {
if (pci_is_bridge(dev)) {
...
}
}

Add a for_each_pci_bridge() helper to make that code easier to write and
read by reducing indentation level. It also saves one or few lines of code
in each occurrence.

Convert PCI core parts here at the same time.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
[bhelgaas: fold in http://lkml.kernel.org/r/20171013165352.25550-1-andriy.shevchenko@linux.intel.com]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

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ACPI / hotplug / PCI: Make device_is_managed_by_native_pciehp() public

We're about to add runtime PM of hotplug ports, but we need to restrict it
to ports that are handled natively by the OS: If th

ACPI / hotplug / PCI: Make device_is_managed_by_native_pciehp() public

We're about to add runtime PM of hotplug ports, but we need to restrict it
to ports that are handled natively by the OS: If they're handled by the
firmware (which is the case for Thunderbolt on non-Macs), things would
break if the OS put the ports into D3hot behind the firmware's back.

To determine if a hotplug port is handled natively, one has to walk up from
the port to the root bridge and check the cached _OSC Control Field for the
value of the "PCI Express Native Hot Plug control" bit. There's already a
function to do that, device_is_managed_by_native_pciehp(), but it's private
to drivers/pci/hotplug/acpiphp_glue.c and only compiled in if
CONFIG_HOTPLUG_PCI_ACPI is enabled.

Make it public and move it to drivers/pci/pci-acpi.c, so that it is
available in the more general CONFIG_ACPI case.

The function contains a check if the device in question is a hotplug port
and returns false if it's not. The caller we're going to add doesn't need
this as it only calls the function if it actually *is* a hotplug port.
Move the check out of the function into the single existing caller.

Rename it to pciehp_is_native() and add some kerneldoc and polish.

No functional change intended.

Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
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>

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ACPI / hotplug / PCI: Use cached copy of PCI_EXP_SLTCAP_HPC bit

We cache the PCI_EXP_SLTCAP_HPC bit in pci_dev->is_hotplug_bridge on device
probe, so there's no need to read it again when adding the

ACPI / hotplug / PCI: Use cached copy of PCI_EXP_SLTCAP_HPC bit

We cache the PCI_EXP_SLTCAP_HPC bit in pci_dev->is_hotplug_bridge on device
probe, so there's no need to read it again when adding the ACPI hotplug
context.

Here's the call chain to prove that no ordering issue is introduced:

pci_scan_child_bus [drivers/pci/probe.c]
pci_scan_slot
pci_scan_single_device
pci_scan_device
pci_setup_device
set_pcie_hotplug_bridge
[is_hotplug_bridge bit is set here]
pci_scan_bridge
pci_add_new_bus
pci_alloc_child_bus
pcibios_add_bus [arch/(x86|arm64|ia64)/...]
acpi_pci_add_bus [drivers/pci/pci-acpi.c]
acpiphp_enumerate_slots [drivers/pci/hotplug/acpiphp_glue.c]
acpiphp_add_context
device_is_managed_by_native_pciehp
[is_hotplug_bridge bit is queried here]

No functional change intended.

Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
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>

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ACPI / hotplug / PCI: Runtime resume bridges before bus rescans

If a PCI bridge (or PCIe port) that is runtime-suspended gets an ACPI
hotplug notification, such as a bus check, it has to be resumed

ACPI / hotplug / PCI: Runtime resume bridges before bus rescans

If a PCI bridge (or PCIe port) that is runtime-suspended gets an ACPI
hotplug notification, such as a bus check, it has to be resumed before
re-scanning the devices below it, or those devices will not be
accessible and will be treated as hot-removed.

Make that happen and let the bridge suspend again after the bus below it
has been re-scanned.

This is a replacement for commit 16468c783cb4 ("ACPI / hotplug / PCI:
Runtime resume bridge before rescan") that has been reverted, because it
introduced a system resume regression (due to missing bridge->pci_dev
checks that are necessary in case the notification is targeted at the
host bridge) and it is necessary for the code added by commit
006d44e49a25 ("PCI: Add runtime PM support for PCIe ports") to work as
expected.

Tested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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Revert "ACPI / hotplug / PCI: Runtime resume bridge before rescan"

This reverts commit 16468c783cb4cf72475dcda23fabecb4a4bb0e17.

Bisection showed that it was the root cause for a resume hang on a
b

Revert "ACPI / hotplug / PCI: Runtime resume bridge before rescan"

This reverts commit 16468c783cb4cf72475dcda23fabecb4a4bb0e17.

Bisection showed that it was the root cause for a resume hang on a
bog-standard all-Intel laptop (Sony Vaio Pro 11), and reverting fixes
the hang.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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