powerpc/iommu: Add iommu_ops to report capabilities and allow blocking domains

Up until now PPC64 managed to avoid using iommu_ops. The VFIO driver
uses a SPAPR TCE sub-driver and all iommu_ops uses

powerpc/iommu: Add iommu_ops to report capabilities and allow blocking domains

Up until now PPC64 managed to avoid using iommu_ops. The VFIO driver
uses a SPAPR TCE sub-driver and all iommu_ops uses were kept in the
Type1 VFIO driver. Recent development added 2 uses of iommu_ops to the
generic VFIO which broke POWER:
- a coherency capability check;
- blocking IOMMU domain - iommu_group_dma_owner_claimed()/...

This adds a simple iommu_ops which reports support for cache coherency
and provides a basic support for blocking domains. No other domain types
are implemented so the default domain is NULL.

Since now iommu_ops controls the group ownership, this takes it out of
VFIO.

This adds an IOMMU device into a pci_controller (=PHB) and registers it
in the IOMMU subsystem, iommu_ops is registered at this point. This
setup is done in postcore_initcall_sync.

This replaces iommu_group_add_device() with iommu_probe_device() as the
former misses necessary steps in connecting PCI devices to IOMMU
devices. This adds a comment about why explicit iommu_probe_device() is
still needed.

The previous discussion is here:
https://lore.kernel.org/r/20220707135552.3688927-1-aik@ozlabs.ru/
https://lore.kernel.org/r/20220701061751.1955857-1-aik@ozlabs.ru/

Fixes: e8ae0e140c05 ("vfio: Require that devices support DMA cache coherence")
Fixes: 70693f470848 ("vfio: Set DMA ownership for VFIO devices")
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Timothy Pearson <tpearson@raptorengineering.com>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
[mpe: Fix CONFIG_IOMMU_API=n build]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/2000135730.16998523.1678123860135.JavaMail.zimbra@raptorengineeringinc.com

show more ...

powerpc/pci: Add option for using pci_to_OF_bus_map

The "pci-OF-bus-map" property was declared deprecated in 2006 [1] and to
the best of everyone's knowledge is not used by anything anymore [2].

Th

powerpc/pci: Add option for using pci_to_OF_bus_map

The "pci-OF-bus-map" property was declared deprecated in 2006 [1] and to
the best of everyone's knowledge is not used by anything anymore [2].

The creation of the property was disabled on powermac (arch/powerpc) in
2005 by commit 35499c0195e4 ("powerpc: Merge in 64-bit powermac
support."). But it is still created by default on CHRP.

On powermac the actual map (pci_to_OF_bus_map) is still used by default,
even though the device tree property is not created.

Add an option to enable/disable use of the pci_to_OF_bus_map, and
creation of the property (on CHRP).

Disabling the option allows enabling CONFIG_PPC_PCI_BUS_NUM_DOMAIN_DEPENDENT
which allows "normal" bus numbering and more than 256 buses, like 64-bit
and other architectures.

Mark the new option as default n, the intention is that the option and
the code will be removed in a future release.

[1]: https://lore.kernel.org/linuxppc-dev/1148016268.13249.14.camel@localhost.localdomain/
[2]: https://lore.kernel.org/all/575f239205e8635add81c9f902b7d9db7beb83ea.camel@kernel.crashing.org/

Signed-off-by: Pali Rohár <pali@kernel.org>
[mpe: Reword commit & help text, shrink option name, rework to fix build errors]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230206113902.1857123-1-mpe@ellerman.id.au

show more ...

powerpc/pci: Hide pci_create_OF_bus_map() for non-chrp code

Function pci_create_OF_bus_map() is used only in chrp code.
So hide it from all other platforms.

Signed-off-by: Pali Rohár <pali@kernel.o

powerpc/pci: Hide pci_create_OF_bus_map() for non-chrp code

Function pci_create_OF_bus_map() is used only in chrp code.
So hide it from all other platforms.

Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220706104308.5390-4-pali@kernel.org

show more ...

powerpc/pci: Hide pci_device_from_OF_node() for non-powermac code

Function pci_device_from_OF_node() is used only in powermac code. So
hide it from all other platforms.

Signed-off-by: Pali Rohár <p

powerpc/pci: Hide pci_device_from_OF_node() for non-powermac code

Function pci_device_from_OF_node() is used only in powermac code. So
hide it from all other platforms.

Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220706104308.5390-2-pali@kernel.org

show more ...

powerpc/64: Move pci_device_from_OF_node() out of asm/pci-bridge.h

Move pci_device_from_OF_node() in pci64.c because it needs definition
of struct device_node and is not worth inlining.

ppc32.c alr

powerpc/64: Move pci_device_from_OF_node() out of asm/pci-bridge.h

Move pci_device_from_OF_node() in pci64.c because it needs definition
of struct device_node and is not worth inlining.

ppc32.c already has it in pci32.c.

That way pci-bridge.h doesn't need linux/of.h (Brought by asm/prom.h
via asm/pci.h)

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/3c88286b55413730d7784133993a46ef4a3607ce.1646767214.git.christophe.leroy@csgroup.eu

show more ...

powerpc/pseries/pci: Add MSI domains

Two IRQ domains are added on top of default machine IRQ domain.

First, the top level "pSeries-PCI-MSI" domain deals with the MSI
specificities. In this domain,

powerpc/pseries/pci: Add MSI domains

Two IRQ domains are added on top of default machine IRQ domain.

First, the top level "pSeries-PCI-MSI" domain deals with the MSI
specificities. In this domain, the HW IRQ numbers are generated by the
PCI MSI layer, they compose a unique ID for an MSI source with the PCI
device identifier and the MSI vector number.

These numbers can be quite large on a pSeries machine running under
the IBM Hypervisor and /sys/kernel/irq/ and /proc/interrupts will
require small fixes to show them correctly.

Second domain is the in-the-middle "pSeries-MSI" domain which acts as
a proxy between the PCI MSI subsystem and the machine IRQ subsystem.
It usually allocate the MSI vector numbers but, on pSeries machines,
this is done by the RTAS FW and RTAS returns IRQ numbers in the IRQ
number space of the machine. This is why the in-the-middle "pSeries-MSI"
domain has the same HW IRQ numbers as its parent domain.

Only the XIVE (P9/P10) parent domain is supported for now. We still
need to add support for IRQ domain hierarchy under XICS.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210701132750.1475580-6-clg@kaod.org

show more ...

powerpc/powernv: remove the nvlink support

This code was only used by the vfio-nvlink2 code, which itself had no
proper use. Drop this huge chunk of code build into every powernv
or generic build.

powerpc/powernv: remove the nvlink support

This code was only used by the vfio-nvlink2 code, which itself had no
proper use. Drop this huge chunk of code build into every powernv
or generic build.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210326061311.1497642-3-hch@lst.de

show more ...

powerpc/eeh: Move vf_index out of pci_dn and into eeh_dev

Drivers that do not support the PCI error handling callbacks are handled by
tearing down the device and re-probing them. If the device being

powerpc/eeh: Move vf_index out of pci_dn and into eeh_dev

Drivers that do not support the PCI error handling callbacks are handled by
tearing down the device and re-probing them. If the device being removed is
a virtual function then we need to know the VF index so it can be removed
using the pci_iov_{add|remove}_virtfn() API.

Currently this is handled by looking up the pci_dn, and using the vf_index
that was stashed there when the pci_dn for the VF was created in
pcibios_sriov_enable(). We would like to eliminate the use of pci_dn
outside of pseries though so we need to provide the generic EEH code with
some other way to find the vf_index.

The easiest thing to do here is move the vf_index field out of pci_dn and
into eeh_dev. Currently pci_dn and eeh_dev are allocated and initialized
together so this is a fairly minimal change in preparation for splitting
pci_dn and eeh_dev in the future.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200725081231.39076-3-oohall@gmail.com

show more ...

powerpc: add an ioremap_phb helper

Factor code shared between pci_64 and electra_cf into a ioremap_pbh helper
that follows the normal ioremap semantics, and returns a useful __iomem
pointer. Note t

powerpc: add an ioremap_phb helper

Factor code shared between pci_64 and electra_cf into a ioremap_pbh helper
that follows the normal ioremap semantics, and returns a useful __iomem
pointer. Note that it opencodes __ioremap_at as we know from the callers
the slab is available. Switch pci_64 to also store the result as __iomem
pointer, and unmap the result using iounmap instead of force casting and
using vmalloc APIs.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200414131348.444715-7-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

show more ...

powerpc/pcidn: Make VF pci_dn management CONFIG_PCI_IOV specific

The powerpc PCI code requires that a pci_dn structure exists for all
devices in the system. This is fine for real devices since at bo

powerpc/pcidn: Make VF pci_dn management CONFIG_PCI_IOV specific

The powerpc PCI code requires that a pci_dn structure exists for all
devices in the system. This is fine for real devices since at boot a pci_dn
is created for each PCI device in the DT and it's fine for hotplugged devices
since the hotplug slot driver will manage the pci_dn's devices in hotplug
slots. For SR-IOV, we need the platform / pcibios to manage the pci_dn for
virtual functions since firmware is unaware of VFs, and they aren't
"hot plugged" in the traditional sense.

Management of the pci_dn is handled by the, poorly named, functions:
add_pci_dev_data() and remove_pci_dev_data(). The entire body of these
functions is #ifdef`ed around CONFIG_PCI_IOV and they cannot be used
in any other context, so make them only available when CONFIG_PCI_IOV
is selected, and rename them to reflect their actual usage rather than
having them masquerade as generic code.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190821062655.19735-2-oohall@gmail.com

show more ...

powerpc/eeh: Fix race when freeing PDNs

When hot-adding devices we rely on the hotplug driver to create pci_dn's
for the devices under the hotplug slot. Converse, when hot-removing the
driver will r

powerpc/eeh: Fix race when freeing PDNs

When hot-adding devices we rely on the hotplug driver to create pci_dn's
for the devices under the hotplug slot. Converse, when hot-removing the
driver will remove the pci_dn's that it created. This is a problem because
the pci_dev is still live until it's refcount drops to zero. This can
happen if the driver is slow to tear down it's internal state. Ideally, the
driver would not attempt to perform any config accesses to the device once
it's been marked as removed, but sometimes it happens. As a result, we
might attempt to access the pci_dn for a device that has been torn down and
the kernel may crash as a result.

To fix this, don't free the pci_dn unless the corresponding pci_dev has
been released. If the pci_dev is still live, then we mark the pci_dn with
a flag that indicates the pci_dev's release function should free it.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190903101605.2890-3-oohall@gmail.com

show more ...

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of th

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

mm: replace all open encodings for NUMA_NO_NODE

Patch series "Replace all open encodings for NUMA_NO_NODE", v3.

All these places for replacement were found by running the following
grep patterns on

mm: replace all open encodings for NUMA_NO_NODE

Patch series "Replace all open encodings for NUMA_NO_NODE", v3.

All these places for replacement were found by running the following
grep patterns on the entire kernel code. Please let me know if this
might have missed some instances. This might also have replaced some
false positives. I will appreciate suggestions, inputs and review.

1. git grep "nid == -1"
2. git grep "node == -1"
3. git grep "nid = -1"
4. git grep "node = -1"

This patch (of 2):

At present there are multiple places where invalid node number is
encoded as -1. Even though implicitly understood it is always better to
have macros in there. Replace these open encodings for an invalid node
number with the global macro NUMA_NO_NODE. This helps remove NUMA
related assumptions like 'invalid node' from various places redirecting
them to a common definition.

Link: http://lkml.kernel.org/r/1545127933-10711-2-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> [ixgbe]
Acked-by: Jens Axboe <axboe@kernel.dk> [mtip32xx]
Acked-by: Vinod Koul <vkoul@kernel.org> [dmaengine.c]
Acked-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc]
Acked-by: Doug Ledford <dledford@redhat.com> [drivers/infiniband]
Cc: Joseph Qi <jiangqi903@gmail.com>
Cc: Hans Verkuil <hverkuil@xs4all.nl>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

show more ...

powerpc/pci: Add pci_find_controller_for_domain()

Add a helper to find the pci_controller structure based on the domain
number / phb id.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed

powerpc/pci: Add pci_find_controller_for_domain()

Add a helper to find the pci_controller structure based on the domain
number / phb id.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

show more ...

powerpc/pci: remove the dma_set_mask pci_controller ops methods

Unused now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc/dma: stop overriding dma_get_required_mask

The ppc_md and pci_controller_ops methods are unused now and can be
removed. The dma_nommu implementation is generic to the generic one
except for

powerpc/dma: stop overriding dma_get_required_mask

The ppc_md and pci_controller_ops methods are unused now and can be
removed. The dma_nommu implementation is generic to the generic one
except for using max_pfn instead of calling into the memblock API,
and all other dma_map_ops instances implement a method of their own.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

show more ...

powerpc/dma: handle iommu bypass in dma_iommu_ops

Add a new iommu_bypass flag to struct dev_archdata so that the dma_iommu
implementation can handle the direct mapping transparently instead of
switi

powerpc/dma: handle iommu bypass in dma_iommu_ops

Add a new iommu_bypass flag to struct dev_archdata so that the dma_iommu
implementation can handle the direct mapping transparently instead of
switiching ops around. Setting of this flag is controlled by new
pci_controller_ops method.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

show more ...

powerpc/powernv: Move npu struct from pnv_phb to pci_controller

The powernv PCI code stores NPU data in the pnv_phb struct. The latter
is referenced by pci_controller::private_data. We are going to

powerpc/powernv: Move npu struct from pnv_phb to pci_controller

The powernv PCI code stores NPU data in the pnv_phb struct. The latter
is referenced by pci_controller::private_data. We are going to have NPU2
support in the pseries platform as well but it does not store any
private_data in in the pci_controller struct; and even if it did,
it would be a different data structure.

This makes npu a pointer and stores it one level higher in
the pci_controller struct.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

show more ...

powerpc/powernv/idoa: Remove unnecessary pcidev from pci_dn

The pcidev value stored in pci_dn is only used for NPU/NPU2
initialization. We can easily drop the cached pointer and
use an ancient helpe

powerpc/powernv/idoa: Remove unnecessary pcidev from pci_dn

The pcidev value stored in pci_dn is only used for NPU/NPU2
initialization. We can easily drop the cached pointer and
use an ancient helper - pci_get_domain_bus_and_slot() instead in order
to reduce complexity.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Acked-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

show more ...

powerpc/pseries: Set eeh_pe of EEH_PE_VF type

To correctly use EEH code one has to make sure that the EEH_PE_VF is
set for dynamic created VFs. Therefore this patch allocates an eeh_pe
of eeh type E

powerpc/pseries: Set eeh_pe of EEH_PE_VF type

To correctly use EEH code one has to make sure that the EEH_PE_VF is
set for dynamic created VFs. Therefore this patch allocates an eeh_pe
of eeh type EEH_PE_VF and associates PE with parent.

Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Signed-off-by: Juan J. Alvarez <jjalvare@linux.vnet.ibm.com>
Acked-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

show more ...

powerpc/pci: Separate SR-IOV Calls

SR-IOV can now be enabled for the powernv platform and pseries
platform. Therefore move the appropriate calls to machine dependent
code instead of relying on defin

powerpc/pci: Separate SR-IOV Calls

SR-IOV can now be enabled for the powernv platform and pseries
platform. Therefore move the appropriate calls to machine dependent
code instead of relying on definition at compile time.

Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Signed-off-by: Juan J. Alvarez <jjalvare@us.ibm.com>
Acked-by: Russell Currey <ruscur@russell.cc>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

show more ...

powerpc/powernv: Reserve a hole which appears after enabling IOV

In order to make generic IOV code work, the physical function IOV BAR
should start from offset of the first VF. Since M64 segments sh

powerpc/powernv: Reserve a hole which appears after enabling IOV

In order to make generic IOV code work, the physical function IOV BAR
should start from offset of the first VF. Since M64 segments share
PE number space across PHB, and some PEs may be in use at the time
when IOV is enabled, the existing code shifts the IOV BAR to the index
of the first PE/VF. This creates a hole in IOMEM space which can be
potentially taken by some other device.

This reserves a temporary hole on a parent and releases it when IOV is
disabled; the temporary resources are stored in pci_dn to avoid
kmalloc/free.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

show more ...

powerpc/pci: Remove OF node back pointer from pci_dn

The check_req() helper uses pci_get_pdn() to get an OF node pointer.
pci_get_pdn() returns a pci_dn pointer which either:
1) from the OF node ret

powerpc/pci: Remove OF node back pointer from pci_dn

The check_req() helper uses pci_get_pdn() to get an OF node pointer.
pci_get_pdn() returns a pci_dn pointer which either:
1) from the OF node returned by pci_device_to_OF_node();
2) from the parent child_list where entries don't have OF node pointers.
Since check_req() does not care about 2), it can call
pci_device_to_OF_node() directly, hence the change.

The find_pe_dn() helper uses embedded pci_dn to get an OF node which is
also stored in edev->pdev so let's take a shortcut and call
pci_device_to_OF_node() directly.

With these 2 changes, we can finally get rid of the OF node back pointer.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

show more ...

powerpc: Move isa bridge definitions to separate include

We'll be adding non-PCI isa bridge support so let's not
have all the definition in pci-bridge.h

Signed-off-by: Benjamin Herrenschmidt <benh@

powerpc: Move isa bridge definitions to separate include

We'll be adding non-PCI isa bridge support so let's not
have all the definition in pci-bridge.h

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

show more ...

powerpc/pseries: use pci_host_bridge.release_fn() to kfree(phb)

This patch leverages 'struct pci_host_bridge' from the PCI subsystem
in order to free the pci_controller only after the last reference

powerpc/pseries: use pci_host_bridge.release_fn() to kfree(phb)

This patch leverages 'struct pci_host_bridge' from the PCI subsystem
in order to free the pci_controller only after the last reference to
its devices is dropped (avoiding an oops in pcibios_release_device()
if the last reference is dropped after pcibios_free_controller()).

The patch relies on pci_host_bridge.release_fn() (and .release_data),
which is called automatically by the PCI subsystem when the root bus
is released (i.e., the last reference is dropped). Those fields are
set via pci_set_host_bridge_release() (e.g. in the platform-specific
implementation of pcibios_root_bridge_prepare()).

It introduces the 'pcibios_free_controller_deferred()' .release_fn()
and it expects .release_data to hold a pointer to the pci_controller.

The function implictly calls 'pcibios_free_controller()', so an user
must *NOT* explicitly call it if using the new _deferred() callback.

The functionality is enabled for pseries (although it isn't platform
specific, and may be used by cxl).

Details on not-so-elegant design choices:

- Use 'pci_host_bridge.release_data' field as pointer to associated
'struct pci_controller' so *not* to 'pci_bus_to_host(bridge->bus)'
in pcibios_free_controller_deferred().

That's because pci_remove_root_bus() sets 'host_bridge->bus = NULL'
(so, if the last reference is released after pci_remove_root_bus()
runs, which eventually reaches pcibios_free_controller_deferred(),
that would hit a null pointer dereference).

The cxl/vphb.c code calls pci_remove_root_bus(), and the cxl folks
are interested in this fix.

Test-case #1 (hold references)

# ls -ld /sys/block/sd* | grep -m1 0021:01:00.0
<...> /sys/block/sdaa -> ../devices/pci0021:01/0021:01:00.0/<...>

# ls -ld /sys/block/sd* | grep -m1 0021:01:00.1
<...> /sys/block/sdab -> ../devices/pci0021:01/0021:01:00.1/<...>

# cat >/dev/sdaa & pid1=$!
# cat >/dev/sdab & pid2=$!

# drmgr -w 5 -d 1 -c phb -s 'PHB 33' -r
Validating PHB DLPAR capability...yes.
[ 594.306719] pci_hp_remove_devices: PCI: Removing devices on bus 0021:01
[ 594.306738] pci_hp_remove_devices: Removing 0021:01:00.0...
...
[ 598.236381] pci_hp_remove_devices: Removing 0021:01:00.1...
...
[ 611.972077] pci_bus 0021:01: busn_res: [bus 01-ff] is released
[ 611.972140] rpadlpar_io: slot PHB 33 removed

# kill -9 $pid1
# kill -9 $pid2
[ 632.918088] pcibios_free_controller_deferred: domain 33, dynamic 1

Test-case #2 (don't hold references)

# drmgr -w 5 -d 1 -c phb -s 'PHB 33' -r
Validating PHB DLPAR capability...yes.
[ 916.357363] pci_hp_remove_devices: PCI: Removing devices on bus 0021:01
[ 916.357386] pci_hp_remove_devices: Removing 0021:01:00.0...
...
[ 920.566527] pci_hp_remove_devices: Removing 0021:01:00.1...
...
[ 933.955873] pci_bus 0021:01: busn_res: [bus 01-ff] is released
[ 933.955977] pcibios_free_controller_deferred: domain 33, dynamic 1
[ 933.955999] rpadlpar_io: slot PHB 33 removed

Suggested-By: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>
Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Tested-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com> # cxl
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

show more ...