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FUJITA Tomonori 584e61452f rust: helpers: Remove volatile qualifier from io helpers
Remove the `volatile` qualifier used with __iomem in helper functions
in io.c. These helper functions are just wrappers around the
corresponding accessors so they are unnecessary.

This fixes the following UML build error with CONFIG_RUST enabled:

In file included from rust/helpers/helpers.c:19:
rust/helpers/io.c:12:10: error: passing 'volatile void *' to parameter of type 'void *' discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]
   12 |         iounmap(addr);
      |                 ^~~~
arch/um/include/asm/io.h:19:42: note: passing argument to parameter 'addr' here
   19 | static inline void iounmap(void __iomem *addr)
      |                                          ^
1 error generated.

[ Arnd explains [1] that removing the qualifier is the way forward
  (thanks!):

    Rihgt, I tried this last week when it came up first, removing the
    'volatile' annotations in the asm-generic/io.h header and then
    all the ones that caused build regressions on arm/arm64/x86
    randconfig and allmodconfig builds.  This patch is a little
    longer than my original version as I did run into a few
    regressions later.

    As far as I can tell, none of these volatile annotations have
    any actual effect, and most of them date back to ancient kernels
    where this may have been required.

    Leaving it out of the rust interface is clearly the right way,
    and it shouldn't be too hard to upstream the changes below
    when we need to, but I also don't see any priority to send these.
    If anyone wants to help out, I can send them the whole patch.

  I created an issue [2] in case someone wants to help. - Miguel ]

Fixes: ce30d94e68 ("rust: add `io::{Io, IoRaw}` base types")
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Cc: stable@vger.kernel.org
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/rust-for-linux/0c844b70-19c7-4b14-ba29-fc99ae0d69f0@app.fastmail.com/ [1]
Link: https://github.com/Rust-for-Linux/linux/issues/1156 [2]
Link: https://lore.kernel.org/r/20250412005341.157150-1-fujita.tomonori@gmail.com
[ Reworded for relative paths. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-04-15 23:03:00 +02:00
arch A set of final cleanups for the timer subsystem: 2025-04-06 08:35:37 -07:00
block treewide: Switch/rename to timer_delete[_sync]() 2025-04-05 10:30:12 +02:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto This push fixes reverts the multibuffer hash testing as it is buggy. 2025-04-02 09:14:59 -07:00
Documentation A set of final cleanups for the timer subsystem: 2025-04-06 08:35:37 -07:00
drivers A set of final cleanups for the timer subsystem: 2025-04-06 08:35:37 -07:00
fs Miscellaneous scheduler fixes/updates: 2025-04-06 10:44:58 -07:00
include A set of final cleanups for the timer subsystem: 2025-04-06 08:35:37 -07:00
init Miscellaneous scheduler fixes/updates: 2025-04-06 10:44:58 -07:00
io_uring io_uring: always do atomic put from iowq 2025-04-03 08:31:57 -06:00
ipc treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
kernel Fix a perf events time accounting bug. 2025-04-06 10:48:12 -07:00
lib Kbuild updates for v6.15 2025-04-05 15:46:50 -07:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm Disable SLUB_TINY for build testing 2025-04-06 10:00:04 -07:00
net treewide: Switch/rename to timer_delete[_sync]() 2025-04-05 10:30:12 +02:00
rust rust: helpers: Remove volatile qualifier from io helpers 2025-04-15 23:03:00 +02:00
samples treewide: Switch/rename to timer_delete[_sync]() 2025-04-05 10:30:12 +02:00
scripts rust: kbuild: use pound to support GNU Make < 4.3 2025-04-15 20:45:46 +02:00
security mseal sysmap: kernel config and header change 2025-04-01 15:17:14 -07:00
sound soundwire fix for 6.15-rc1 2025-04-06 12:04:53 -07:00
tools objtool/rust: add one more noreturn Rust function for Rust 1.86.0 2025-04-14 17:02:49 +02:00
usr kbuild: hdrcheck: fix cross build with clang 2025-03-05 04:06:45 +09:00
virt ARM: 2025-03-25 14:22:07 -07:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: give Clippy the minimum supported Rust version 2025-01-10 00:17:25 +01:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: Create intermediate vmlinux build with relocations preserved 2025-03-17 00:29:50 +09:00
.mailmap mailmap: add an entry for Nicolas Schier 2025-04-01 15:20:45 -07:00
.rustfmt.toml
COPYING
CREDITS Including fixes from netfilter. 2025-04-04 09:15:35 -07:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS Kbuild updates for v6.15 2025-04-05 15:46:50 -07:00
Makefile rust: disable clippy::needless_continue 2025-04-14 16:10:47 +02:00
README README: Fix spelling 2024-03-18 03:36:32 -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 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.