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Maciej W. Rozycki 0e32818397 PCI: Sanitise firmware BAR assignments behind a PCI-PCI bridge
When pci_assign_resource() is unable to assign resources to a BAR, it uses
pci_revert_fw_address() to fall back to a firmware assignment (if any).
Previously pci_revert_fw_address() assumed all addresses could reach the
device, but this is not true if the device is below a bridge that only
forwards addresses within its windows.

This problem was observed on a Tyan Tomcat IV S1564D system where the BIOS
did not assign valid addresses to several bridges and USB devices:

  pci 0000:00:11.0: PCI-to-PCIe bridge to [bus 01-ff]
  pci 0000:00:11.0:   bridge window [io  0xe000-0xefff]
  pci 0000:01:00.0: PCIe Upstream Port to [bus 02-ff]
  pci 0000:01:00.0:   bridge window [io  0x0000-0x0fff]   # unreachable
  pci 0000:02:02.0: PCIe Downstream Port to [bus 05-ff]
  pci 0000:02:02.0:   bridge window [io  0x0000-0x0fff]   # unreachable
  pci 0000:05:00.0: PCIe-to-PCI bridge to [bus 06-ff]
  pci 0000:05:00.0:   bridge window [io  0x0000-0x0fff]   # unreachable
  pci 0000:06:08.0: USB UHCI 1.1
  pci 0000:06:08.0: BAR 4: [io  0xfce0-0xfcff]            # unreachable
  pci 0000:06:08.1: USB UHCI 1.1
  pci 0000:06:08.1: BAR 4: [io  0xfce0-0xfcff]            # unreachable
  pci 0000:06:08.0: can't claim BAR 4 [io  0xfce0-0xfcff]: no compatible bridge window
  pci 0000:06:08.1: can't claim BAR 4 [io  0xfce0-0xfcff]: no compatible bridge window

During the first pass of assigning unassigned resources, there was not
enough I/O space available, so we couldn't assign the 06:08.0 BAR and
reverted to the firmware assignment (still unreachable).  Reverting the
06:08.1 assignment failed because it conflicted with 06:08.0:

  pci 0000:00:11.0:   bridge window [io  0xe000-0xefff]
  pci 0000:01:00.0: no space for bridge window [io  size 0x2000]
  pci 0000:02:02.0: no space for bridge window [io  size 0x1000]
  pci 0000:05:00.0: no space for bridge window [io  size 0x1000]
  pci 0000:06:08.0: BAR 4: no space for [io  size 0x0020]
  pci 0000:06:08.0: BAR 4: trying firmware assignment [io  0xfce0-0xfcff]
  pci 0000:06:08.1: BAR 4: no space for [io  size 0x0020]
  pci 0000:06:08.1: BAR 4: trying firmware assignment [io  0xfce0-0xfcff]
  pci 0000:06:08.1: BAR 4: [io  0xfce0-0xfcff] conflicts with 0000:06:08.0 [io  0xfce0-0xfcff]

A subsequent pass assigned valid bridge windows and a valid 06:08.1 BAR,
but left the 06:08.0 BAR alone, so the UHCI device was still unusable:

  pci 0000:00:11.0:   bridge window [io  0xe000-0xefff] released
  pci 0000:00:11.0:   bridge window [io  0x1000-0x2fff]   # reassigned
  pci 0000:01:00.0:   bridge window [io  0x1000-0x2fff]   # reassigned
  pci 0000:02:02.0:   bridge window [io  0x2000-0x2fff]   # reassigned
  pci 0000:05:00.0:   bridge window [io  0x2000-0x2fff]   # reassigned
  pci 0000:06:08.0: BAR 4: assigned [io  0xfce0-0xfcff]   # left alone
  pci 0000:06:08.1: BAR 4: assigned [io  0x2000-0x201f]
  ...
  uhci_hcd 0000:06:08.0: host system error, PCI problems?
  uhci_hcd 0000:06:08.0: host controller process error, something bad happened!
  uhci_hcd 0000:06:08.0: host controller halted, very bad!
  uhci_hcd 0000:06:08.0: HCRESET not completed yet!
  uhci_hcd 0000:06:08.0: HC died; cleaning up

If the address assigned by firmware is not reachable because it's not
within upstream bridge windows, fail instead of assigning the unusable
address from firmware.

[bhelgaas: commit log, use pci_upstream_bridge()]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=16263
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2203012338460.46819@angie.orcam.me.uk
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2209211921250.29493@angie.orcam.me.uk
Fixes: 58c84eda07 ("PCI: fall back to original BIOS BAR addresses")
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org # v2.6.35+
History 2022-09-21 17:52:47 -05:00
arch xen: branch for v6.0-rc1b 2022-08-14 09:28:54 -07:00
block block-6.0-2022-08-12 2022-08-13 13:37:36 -07:00
certs Kbuild updates for v5.20 2022-08-10 10:40:41 -07:00
crypto crypto: blake2b: effectively disable frame size warning 2022-08-10 17:59:11 -07:00
Documentation xen: branch for v6.0-rc1b 2022-08-14 09:28:54 -07:00
drivers PCI: Sanitise firmware BAR assignments behind a PCI-PCI bridge 2022-09-21 17:52:47 -05:00
fs take care to handle NULL ->proc_lseek() 2022-08-14 15:16:18 -04:00
include radix-tree: replace gfp.h inclusion with gfp_types.h 2022-08-14 13:31:03 -07:00
init Kbuild updates for v5.20 2022-08-10 10:40:41 -07:00
io_uring io_uring-6.0-2022-08-13 2022-08-13 13:28:54 -07:00
ipc Updates to various subsystems which I help look after. lib, ocfs2, 2022-08-07 10:03:24 -07:00
kernel xen: branch for v6.0-rc1b 2022-08-14 09:28:54 -07:00
lib lib: remove lib/nodemask.c 2022-08-12 09:07:33 -07:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm - hugetlb_vmemmap cleanups from Muchun Song 2022-08-10 11:18:00 -07:00
net Including fixes from bluetooth, bpf, can and netfilter. 2022-08-11 13:45:37 -07:00
samples Tracing updates for 5.20 / 6.0 2022-08-05 09:41:12 -07:00
scripts RISC-V Patches for the 5.20 Merge Window, Part 2 2022-08-12 18:39:43 -07:00
security + Features 2022-08-10 10:53:22 -07:00
sound sound fixes for 6.0-rc1 2022-08-12 09:55:32 -07:00
tools perf tools changes for v6.0: 2nd batch 2022-08-14 09:22:11 -07:00
usr Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
virt KVM: Actually create debugfs in kvm_create_vm() 2022-08-10 15:08:28 -04:00
.clang-format PCI/DOE: Add DOE mailbox support functions 2022-07-19 15:38:04 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore kbuild: split the second line of *.mod into *.usyms 2022-05-08 03:16:59 +09:00
.mailmap Updates to various subsystems which I help look after. lib, ocfs2, 2022-08-07 10:03:24 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS drm for 5.20/6.0 2022-08-03 19:52:08 -07:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS xen: branch for v6.0-rc1b 2022-08-14 09:28:54 -07:00
Makefile Linux 6.0-rc1 2022-08-14 15:50:18 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.