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Filename Latest commit message Latest commit date
Nicholas Johnson 797f6c19ab PCI: Avoid double hpmemsize MMIO window assignment
[ Upstream commit c13704f5685deb7d6eb21e293233e0901ed77377 ]

Previously, the kernel sometimes assigned more MMIO or MMIO_PREF space than
desired.  For example, if the user requested 128M of space with
"pci=realloc,hpmemsize=128M", we sometimes assigned 256M:

  pci 0000:06:01.0: BAR 14: assigned [mem 0x90100000-0xa00fffff] = 256M
  pci 0000:06:04.0: BAR 14: assigned [mem 0xa0200000-0xb01fffff] = 256M

With this patch applied:

  pci 0000:06:01.0: BAR 14: assigned [mem 0x90100000-0x980fffff] = 128M
  pci 0000:06:04.0: BAR 14: assigned [mem 0x98200000-0xa01fffff] = 128M

This happened when in the first pass, the MMIO_PREF succeeded but the MMIO
failed. In the next pass, because MMIO_PREF was already assigned, the
attempt to assign MMIO_PREF returned an error code instead of success
(nothing more to do, already allocated). Hence, the size which was actually
allocated, but thought to have failed, was placed in the MMIO window.

The bug resulted in the MMIO_PREF being added to the MMIO window, which
meant doubling if MMIO_PREF size = MMIO size. With a large MMIO_PREF, the
MMIO window would likely fail to be assigned altogether due to lack of
32-bit address space.

Change find_free_bus_resource() to do the following:

  - Return first unassigned resource of the correct type.
  - If there is none, return first assigned resource of the correct type.
  - If none of the above, return NULL.

Returning an assigned resource of the correct type allows the caller to
distinguish between already assigned and no resource of the correct type.

Add checks in pbus_size_io() and pbus_size_mem() to return success if
resource returned from find_free_bus_resource() is already allocated.

This avoids pbus_size_io() and pbus_size_mem() returning error code to
__pci_bus_size_bridges() when a resource has been successfully assigned in
a previous pass. This fixes the existing behaviour where space for a
resource could be reserved multiple times in different parent bridge
windows.

Link: https://lore.kernel.org/lkml/20190531171216.20532-2-logang@deltatee.com/T/#u
Link: https://bugzilla.kernel.org/show_bug.cgi?id=203243
Link: https://lore.kernel.org/r/PS2P216MB075563AA6AD242AA666EDC6A80760@PS2P216MB0755.KORP216.PROD.OUTLOOK.COM
Reported-by: Kit Chow <kchow@gigaio.com>
Reported-by: Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au>
Signed-off-by: Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-01 13:17:19 +02:00
arch x86/kdump: Always reserve the low 1M when the crashkernel option is specified 2020-10-01 13:17:18 +02:00
block block: only call sched requeue_request() for scheduled requests 2020-09-23 12:40:37 +02:00
certs
crypto crypto: af_alg - Work around empty control messages without MSG_MORE 2020-09-03 11:27:05 +02:00
Documentation affs: fix basic permission bits to actually work 2020-09-09 19:12:34 +02:00
drivers PCI: Avoid double hpmemsize MMIO window assignment 2020-10-01 13:17:19 +02:00
fs f2fs: avoid kernel panic on corruption test 2020-10-01 13:17:16 +02:00
include net: silence data-races on sk_backlog.tail 2020-10-01 13:17:15 +02:00
init x86: Fix early boot crash on gcc-10, third try 2020-05-20 08:20:34 +02:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel tracing: Adding NULL checks for trace_array descriptor pointer 2020-10-01 13:17:17 +02:00
lib kernel/sysctl-test: Add null pointer test for sysctl.c:proc_dointvec() 2020-10-01 13:17:10 +02:00
LICENSES
mm mm: fix double page fault on arm64 if PTE_AF is cleared 2020-10-01 13:17:12 +02:00
net net: silence data-races on sk_backlog.tail 2020-10-01 13:17:15 +02:00
samples bpf: Fix fds_example SIGSEGV error 2020-08-19 08:16:03 +02:00
scripts checkpatch: fix the usage of capture group ( ... ) 2020-09-09 19:12:37 +02:00
security selinux: allow labeling before policy is loaded 2020-10-01 13:17:10 +02:00
sound ASoC: kirkwood: fix IRQ error handling 2020-10-01 13:17:13 +02:00
tools selftests/vm: fix display of page size in map_hugetlb 2020-09-23 12:40:46 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: fix memory leak in kvm_io_bus_unregister_dev() 2020-09-17 13:47:54 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild
Kconfig
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-08-26 10:40:46 +02:00
Makefile Linux 5.4.68 2020-09-26 18:03:16 +02:00
README

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.