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Huacai Chen 104c82d862 PCI/portdrv: Prevent LS7A Bus Master clearing on shutdown 
[ Upstream commit 62b6dee1b4 ]

After cc27b735ad ("PCI/portdrv: Turn off PCIe services during shutdown")
we observe hangs during poweroff/reboot on systems with LS7A chipset.

This happens because the portdrv .shutdown() method (pcie_portdrv_remove())
clears PCI_COMMAND_MASTER via pci_disable_device(), which prevents bridges
from forwarding memory or I/O Requests in the upstream direction (PCIe
r6.0, sec 7.5.1.1.3).

LS7A Root Ports have a hardware defect: clearing PCI_COMMAND_MASTER *also*
prevents the bridge from forwarding CPU MMIO requests in the downstream
direction, and these MMIO accesses to devices below the bridge happen even
after .shutdown(), e.g., to print console messages.  LS7A neither forwards
the requests nor sends an unsuccessful completion to the CPU, so the CPU
waits forever, resulting in the hang.

The purpose of .shutdown() is to disable interrupts and DMA from the
device.  PCIe ports may generate interrupts (either MSI/MSI-X or INTx) for
AER, DPC, PME, hotplug, etc., but they never perform DMA except MSI/MSI-X.
Clearing PCI_COMMAND_MASTER effectively disables MSI/MSI-X, but not INTx.

The port service driver .remove() methods clear the interrupt enables in
PCI_ERR_ROOT_COMMAND, PCI_EXP_DPC_CTL, PCI_EXP_SLTCTL, and PCI_EXP_RTCTL,
etc., which disables interrupts regardless of whether they are MSI/MSI-X or
INTx.

Add a pcie_portdrv_shutdown() method that calls all the port service driver
.remove() methods to clear the interrupt enables for each service but does
not clear Bus Mastering on the port itself.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20230201043018.778499-2-chenhuacai@loongson.cn
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2023-03-11 13:50:41 +01:00
arch ARM: dts: spear320-hmi: correct STMPE GPIO compatible 2023-03-11 13:50:34 +01:00
block Revert "blk-cgroup: dropping parent refcount after pd_free_fn() is done" 2023-03-11 11:04:54 +01:00
certs certs: Fix build error when PKCS#11 URI contains semicolon 2023-01-31 17:53:01 +09:00
crypto crypto: rsa-pkcs1pad - Use akcipher_request_complete 2023-03-10 09:28:18 +01:00
Documentation dt-bindings: usb: Add device id for Genesys Logic hub controller 2023-03-11 13:50:40 +01:00
drivers PCI/portdrv: Prevent LS7A Bus Master clearing on shutdown 2023-03-11 13:50:41 +01:00
fs ext4: fix incorrect options show of original mount_opt and extend mount_opt2 2023-03-11 13:50:33 +01:00
include media: uvcvideo: Add GUID for BGRA/X 8:8:8:8 2023-03-11 13:50:41 +01:00
init Kbuild fixes for v6.2 (3rd) 2023-01-21 10:56:37 -08:00
io_uring io_uring: fix size calculation when registering buf ring 2023-03-11 13:50:35 +01:00
ipc Non-MM patches for 6.2-rc1. 2022-12-12 17:28:58 -08:00
kernel kernel/printk/index.c: fix memory leak with using debugfs_lookup() 2023-03-11 13:50:37 +01:00
lib cpuidle: lib/bug: Disable rcu_is_watching() during WARN/BUG 2023-03-10 09:29:06 +01:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm memory tier: release the new_memtier in find_create_memory_tier() 2023-03-10 09:29:50 +01:00
net tcp: tcp_check_req() can be called from process context 2023-03-11 13:50:34 +01:00
rust rust: print: avoid evaluating arguments in pr_* macros in unsafe blocks 2023-01-16 00:54:35 +01:00
samples ftrace: Export ftrace_free_filter() to modules 2023-01-24 11:20:58 -05:00
scripts gcc-plugins: drop -std=gnu++11 to fix GCC 13 build 2023-03-10 09:29:11 +01:00
security ima: Align ima_file_mmap() parameters with mmap_file LSM hook 2023-03-10 09:29:36 +01:00
sound ASoC: mediatek: mt8195: add missing initialization 2023-03-11 13:50:37 +01:00
tools tools/iio/iio_utils:fix memory leak 2023-03-11 13:50:40 +01:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM: Register /dev/kvm as the _very_ last thing during initialization 2023-03-10 09:29:33 +01:00
.clang-format iommufd for 6.2 2022-12-14 09:15:43 -08:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore *.rpm 2022-12-30 17:22:14 +09:00
.mailmap 12 hotfixes, mostly against mm/. Five of these fixes are cc:stable. 2023-02-13 14:09:20 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: update SCTP maintainers 2023-02-02 11:35:33 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS audit: update the mailing list in MAINTAINERS 2023-02-25 11:13:29 +01:00
Makefile Linux 6.2.4 2023-03-11 11:04:54 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.