[PATCH 0/5] Add READ_ONCE and WRITE_ONCE to Rust

[Alice Ryhl]

There are currently a few places in the kernel where we use volatile
reads when we really should be using `READ_ONCE`. To make it possible to
replace these with proper `READ_ONCE` calls, introduce a Rust version of
`READ_ONCE`.

A new config option CONFIG_ARCH_USE_CUSTOM_READ_ONCE is introduced so
that Rust is able to use conditional compilation to implement READ_ONCE
in terms of either a volatile read, or by calling into a C helper
function, depending on the architecture.

This series is intended to be merged through ATOMIC INFRASTRUCTURE.

Signed-off-by: Alice Ryhl <aliceryhl at google.com>
---
Alice Ryhl (5):
      arch: add CONFIG_ARCH_USE_CUSTOM_READ_ONCE for arm64/alpha
      rust: sync: add READ_ONCE and WRITE_ONCE
      rust: sync: support using bool with READ_ONCE
      rust: hrtimer: use READ_ONCE instead of read_volatile
      rust: fs: use READ_ONCE instead of read_volatile

 MAINTAINERS                     |   2 +
 arch/Kconfig                    |  11 +++
 arch/alpha/Kconfig              |   1 +
 arch/alpha/include/asm/rwonce.h |   4 +-
 arch/arm64/Kconfig              |   1 +
 arch/arm64/include/asm/rwonce.h |   4 +-
 rust/helpers/helpers.c          |   1 +
 rust/helpers/rwonce.c           |  34 +++++++
 rust/kernel/fs/file.rs          |   8 +-
 rust/kernel/sync.rs             |   2 +
 rust/kernel/sync/rwonce.rs      | 207 ++++++++++++++++++++++++++++++++++++++++
 rust/kernel/time/hrtimer.rs     |   8 +-
 12 files changed, 268 insertions(+), 15 deletions(-)
---
base-commit: f8f9c1f4d0c7a64600e2ca312dec824a0bc2f1da
change-id: 20251230-rwonce-1e8d2ee0bcf9

Best regards,
-- 
Alice Ryhl <aliceryhl at google.com>