linux-stable.git/rust/helpers/uaccess.c, branch linux-rolling-stable

uaccess: unify inline vs outline copy_{from,to}_user() selection

2026-07-24T14:19:23+00:00

[ Upstream commit c02be2ad2b88c67c5d7c06b6aa7083b5b40e1077 ]

The kernel allows arches to select between inline and outline
implementations of the copy_{from,to}_user() by defining individual
INLINE_COPY_FROM_USER and INLINE_COPY_TO_USER, correspondingly.  However,
all arches enable or disable them always together.

Without the real use-case for one helper being inlined while the other
outlined, having independent controls is excessive and error prone.

Switch the codebase to the single unified INLINE_COPY_USER control.

Link: https://lore.kernel.org/20260425020857.356850-3-ynorov@nvidia.com
Signed-off-by: Yury Norov 
Tested-by: Alice Ryhl 
Cc: Arnd Bergmann 
Cc: Christophe Leroy (CS GROUP) 
Cc: Mathieu Desnoyers 
Cc: Peter Zijlstra 
Cc: Randy Dunlap 
Cc: Viktor Malik 
Signed-off-by: Andrew Morton 
Stable-dep-of: bd99fcfc6219 ("uaccess: minimize INLINE_COPY_USER-related ifdefery")
Signed-off-by: Sasha Levin

rust: uaccess: use INLINE_COPY_TO_USER to guard copy_to_user()

2026-07-24T14:19:23+00:00

[ Upstream commit f829d4d911cc296b32d14436a8a517e907228475 ]

Patch series "uaccess: unify inline vs outline copy_{from,to}_user()
selection", v2.

The kernel allows arches to select between inline and outline
implementations of the copy_{from,to}_user() by defining individual
INLINE_COPY_FROM_USER and INLINE_COPY_TO_USER, correspondingly.  However,
all arches enable or disable them always together.

Without the real use-case for one helper being inlined while the other
outlined, having independent controls is excessive and error prone.

The first patch of the series fixes rust/uaccess coppy_to_user() wrapper
guarded with INLINE_COPY_FROM_USER.  The 2nd patch switches codebase to
the unified INLINE_COPY_USER.  And the last patch cleans up ifdefery in
the include/linux/uaccess.h

This patch (of 3):

The copy_to_user() rust helper is only needed when the main kernel inlines
the function.  It is controlled by INLINE_COPY_TO_USER, but the rust
helper is protected with INLINE_COPY_FROM_USER.

Fix that.

Link: https://lore.kernel.org/20260425020857.356850-1-ynorov@nvidia.com
Link: https://lore.kernel.org/20260425020857.356850-2-ynorov@nvidia.com
Fixes: d99dc586ca7c7 ("uaccess: decouple INLINE_COPY_FROM_USER and CONFIG_RUST")
Signed-off-by: Yury Norov 
Reported-by: Christophe Leroy (CS GROUP) 
Closes: https://lore.kernel.org/all/746c9c50-20c4-4dc9-a539-bf1310ff9414@kernel.org/
Cc: Alice Ryhl 
Cc: Mathieu Desnoyers 
Cc: Peter Zijlstra 
Cc: Randy Dunlap 
Cc: Viktor Malik 
Cc: Arnd Bergmann 
Signed-off-by: Andrew Morton 
Signed-off-by: Sasha Levin

rust: uaccess: add __rust_helper to helpers

2026-01-26T02:51:16+00:00

This is needed to inline these helpers into Rust code.

Reviewed-by: Boqun Feng 
Reviewed-by: Gary Guo 
Signed-off-by: Alice Ryhl 
Link: https://patch.msgid.link/20260105-define-rust-helper-v2-23-51da5f454a67@google.com
Signed-off-by: Miguel Ojeda

uaccess: decouple INLINE_COPY_FROM_USER and CONFIG_RUST

2025-11-12T18:00:16+00:00

Commit 1f9a8286bc0c ("uaccess: always export _copy_[from|to]_user with
CONFIG_RUST") exports _copy_{from,to}_user() unconditionally, if RUST is
enabled.  This pollutes exported symbols namespace, and spreads RUST
ifdefery in core files.

It's better to declare a corresponding helper under the rust/helpers,
similarly to how non-underscored copy_{from,to}_user() is handled.

[yury.norov@gmail.com: drop rust part of comment for _copy_from_user(), per Alice]
  Link: https://lkml.kernel.org/r/20251024154754.99768-1-yury.norov@gmail.com
Link: https://lkml.kernel.org/r/20251023171607.1171534-1-yury.norov@gmail.com
Signed-off-by: Yury Norov (NVIDIA) 
Acked-by: Arnd Bergmann 
Acked-by: Miguel Ojeda 
Reviewed-by: Alice Ryhl 
Tested-by: Alice Ryhl 
Cc: Alex Gaynor 
Cc: Andreas Hindborg 
Cc: Björn Roy Baron 
Cc: Boqun Feng 
Cc: Danilo Krummrich 
Cc: Gary Guo 
Cc: John Hubbard 
Cc: Trevor Gross 
Signed-off-by: Andrew Morton

rust: kbuild: auto generate helper exports

2024-08-19T09:09:02+00:00

This removes the need to explicitly export all symbols.

Generate helper exports similarly to what's currently done for Rust
crates. These helpers are exclusively called from within Rust code and
therefore can be treated similar as other Rust symbols.

Signed-off-by: Gary Guo 
Reviewed-by: Boqun Feng 
Tested-by: Boqun Feng 
Link: https://lore.kernel.org/r/20240817165302.3852499-1-gary@garyguo.net
[ Fixed dependency path, reworded slightly, edited comment a bit and
  rebased on top of the changes made when applying Andreas' patch
  (e.g. no `README.md` anymore, so moved the edits).  - Miguel ]
Signed-off-by: Miguel Ojeda

rust: kbuild: split up helpers.c

2024-08-18T21:34:26+00:00

This patch splits up the rust helpers C file. When rebasing patch sets on
upstream linux, merge conflicts in helpers.c is common and time consuming
[1]. Thus, split the file so that each kernel component can live in a
separate file.

This patch lists helper files explicitly and thus conflicts in the file
list is still likely. However, they should be more simple to resolve than
the conflicts usually seen in helpers.c.

[ Removed `README.md` and undeleted the original comment since now,
  in v3 of the series, we have a `helpers.c` again; which also allows
  us to keep the "Sorted alphabetically" line and makes the diff easier.

  In addition, updated the Documentation/ mentions of the file, reworded
  title and removed blank lines at the end of `page.c`.  - Miguel ]

Link: https://rust-for-linux.zulipchat.com/#narrow/stream/288089-General/topic/Splitting.20up.20helpers.2Ec/near/426694012 [1]
Signed-off-by: Andreas Hindborg 
Reviewed-by: Gary Guo 
Acked-by: Dirk Behme 
Reviewed-by: Alice Ryhl 
Reviewed-by: Benno Lossin 
Link: https://lore.kernel.org/r/20240815103016.2771842-1-nmi@metaspace.dk
Signed-off-by: Miguel Ojeda