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Rafael J. Wysocki c2ddeb2961 genirq: Introduce IRQF_COND_ONESHOT and use it in pinctrl-amd
There is a problem when a driver requests a shared interrupt line to run a
threaded handler on it without IRQF_ONESHOT set if that flag has been set
already for the IRQ in question by somebody else.  Namely, the request
fails which usually leads to a probe failure even though the driver might
have worked just fine with IRQF_ONESHOT, but it does not want to use it by
default.  Currently, the only way to handle this is to try to request the
IRQ without IRQF_ONESHOT, but with IRQF_PROBE_SHARED set and if this fails,
try again with IRQF_ONESHOT set.  However, this is a bit cumbersome and not
very clean.

When commit 7a36b901a6 ("ACPI: OSL: Use a threaded interrupt handler for
SCI") switched the ACPI subsystem over to using a threaded interrupt
handler for the SCI, it had to use IRQF_ONESHOT for it because that's
required due to the way the SCI handler works (it needs to walk all of the
enabled GPEs before the interrupt line can be unmasked). The SCI interrupt
line is not shared with other users very often due to the SCI handling
overhead, but on sone systems it is shared and when the other user of it
attempts to install a threaded handler, a flags mismatch related to
IRQF_ONESHOT may occur.

As it turned out, that happened to the pinctrl-amd driver and so commit
4451e8e841 ("pinctrl: amd: Add IRQF_ONESHOT to the interrupt request")
attempted to address the issue by adding IRQF_ONESHOT to the interrupt
flags in that driver, but this is now causing an IRQF_ONESHOT-related
mismatch to occur on another system which cannot boot as a result of it.

Clearly, pinctrl-amd can work with IRQF_ONESHOT if need be, but it should
not set that flag by default, so it needs a way to indicate that to the
interrupt subsystem.

To that end, introdcuce a new interrupt flag, IRQF_COND_ONESHOT, which will
only have effect when the IRQ line is shared and IRQF_ONESHOT has been set
for it already, in which case it will be promoted to the latter.

This is sufficient for drivers sharing the interrupt line with the SCI as
it is requested by the ACPI subsystem before any drivers are probed, so
they will always see IRQF_ONESHOT set for the interrupt in question.

Fixes: 4451e8e841 ("pinctrl: amd: Add IRQF_ONESHOT to the interrupt request")
Reported-by: Francisco Ayala Le Brun <francisco@videowindow.eu>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Cc: 6.8+ <stable@vger.kernel.org> # 6.8+
Closes: https://lore.kernel.org/lkml/CAN-StX1HqWqi+YW=t+V52-38Mfp5fAz7YHx4aH-CQjgyNiKx3g@mail.gmail.com/
Link: https://lore.kernel.org/r/12417336.O9o76ZdvQC@kreacher
2024-03-25 23:45:21 +01:00
Documentation A set of x86 fixes: 2024-03-24 11:13:56 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
arch EFI fixes for v6.9 #2 2024-03-24 13:54:06 -07:00
block vfs-6.9-rc1.fixes 2024-03-18 09:15:50 -07:00
certs This update includes the following changes: 2023-11-02 16:15:30 -10:00
crypto RISC-V Patches for the 6.9 Merge Window 2024-03-22 10:41:13 -07:00
drivers genirq: Introduce IRQF_COND_ONESHOT and use it in pinctrl-amd 2024-03-25 23:45:21 +01:00
fs A patch to minimize blockage when processing very large batches of 2024-03-22 11:15:45 -07:00
include genirq: Introduce IRQF_COND_ONESHOT and use it in pinctrl-amd 2024-03-25 23:45:21 +01:00
init RISC-V Patches for the 6.9 Merge Window 2024-03-22 10:41:13 -07:00
io_uring io_uring/sqpoll: early exit thread if task_context wasn't allocated 2024-03-18 20:22:42 -06:00
ipc sysctl changes for v6.9-rc1 2024-03-18 14:59:13 -07:00
kernel genirq: Introduce IRQF_COND_ONESHOT and use it in pinctrl-amd 2024-03-25 23:45:21 +01:00
lib hardening fixes for v6.9-rc1 2024-03-23 08:43:21 -07:00
mm RISC-V Patches for the 6.9 Merge Window 2024-03-22 10:41:13 -07:00
net Including fixes from CAN, netfilter, wireguard and IPsec. 2024-03-21 14:50:39 -07:00
rust Kbuild updates for v6.9 2024-03-21 14:41:00 -07:00
samples Tracing updates for 6.9: 2024-03-18 15:11:44 -07:00
scripts LoongArch changes for v6.9 2024-03-22 10:22:45 -07:00
security - Kuan-Wei Chiu has developed the well-named series "lib min_heap: Min 2024-03-14 18:03:09 -07:00
sound sound fixes #2 for 6.9-rc2 2024-03-22 09:44:19 -07:00
tools RISC-V Patches for the 6.9 Merge Window 2024-03-22 10:41:13 -07:00
usr Kbuild updates for v6.8 2024-01-18 17:57:07 -08:00
virt KVM Xen and pfncache changes for 6.9: 2024-03-11 10:42:55 -04:00
.clang-format clang-format: Update with v6.7-rc4's `for_each` macro list 2023-12-08 23:54:38 +01:00
.cocciconfig
.editorconfig Add .editorconfig file for basic formatting 2023-12-28 16:22:47 +09:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: create a list of all built DTB files 2024-02-19 18:20:39 +09:00
.mailmap Char/Misc and other driver subsystem updates for 6.9-rc1 2024-03-21 13:21:31 -07:00
.rustfmt.toml rust: add `.rustfmt.toml` 2022-09-28 09:02:20 +02:00
COPYING
CREDITS Not a ton of stuff happening in the clk framework in this pull request. We got 2024-03-15 11:48:01 -07:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig
MAINTAINERS RISC-V Patches for the 6.9 Merge Window 2024-03-22 10:41:13 -07:00
Makefile Linux 6.9-rc1 2024-03-24 14:10:05 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -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 reStructuredText 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.