[PATCH v2 0/4] Memory management patches needed by Rust Binder

From: Alice Ryhl
Date: Thu Feb 08 2024 - 10:48:50 EST

This patchset contains some abstractions needed by the Rust
implementation of the Binder driver for passing data between userspace,
kernelspace, and directly into other processes.

These abstractions do not exactly match what was included in the Rust
Binder RFC - I have made various improvements and simplifications since
then. Nonetheless, please see the Rust Binder RFC [1] to get an
understanding for how this will be used:

Users of "rust: add userspace pointers"
and "rust: add typed accessors for userspace pointers":
rust_binder: add binderfs support to Rust binder
rust_binder: add threading support
rust_binder: add nodes and context managers
rust_binder: add oneway transactions
rust_binder: add death notifications
rust_binder: send nodes in transactions
rust_binder: add BINDER_TYPE_PTR support
rust_binder: add BINDER_TYPE_FDA support
rust_binder: add process freezing

Users of "rust: add abstraction for `struct page`":
rust_binder: add oneway transactions
rust_binder: add vma shrinker

Especially the second patch with typed accessors needs review. It
contains a Rust analogy for when the C-side skips `check_object_size`,
and I would be very happy to receive feedback about whether I am going
about this in a reasonable way.

Links: https://lore.kernel.org/rust-for-linux/20231101-rust-binder-v1-0-08ba9197f637@xxxxxxxxxx/ [1]
Signed-off-by: Alice Ryhl <aliceryhl@xxxxxxxxxx>
Changes in v2:
- Rename user_ptr module to uaccess.
- Use srctree-relative links.
- Improve documentation.
- Rename UserSlicePtr to UserSlice.
- Make read_to_end append to the buffer.
- Use named fields for uaccess types.
- Add examples.
- Use _copy_from/to_user to skip check_object_size.
- Rename traits and move to kernel::types.
- Remove PAGE_MASK constant.
- Rename page methods to say _raw.
- Link to v1: https://lore.kernel.org/r/20240124-alice-mm-v1-0-d1abcec83c44@xxxxxxxxxx

Alice Ryhl (2):
rust: uaccess: add typed accessors for userspace pointers
rust: add abstraction for `struct page`

Arnd Bergmann (1):
uaccess: always export _copy_[from|to]_user with CONFIG_RUST

Wedson Almeida Filho (1):
rust: uaccess: add userspace pointers

include/linux/uaccess.h | 37 ++--
lib/usercopy.c | 30 +---
rust/bindings/bindings_helper.h | 1 +
rust/helpers.c | 34 ++++
rust/kernel/lib.rs | 2 +
rust/kernel/page.rs | 209 ++++++++++++++++++++++
rust/kernel/types.rs | 67 +++++++
rust/kernel/uaccess.rs | 387 ++++++++++++++++++++++++++++++++++++++++
8 files changed, 727 insertions(+), 40 deletions(-)
base-commit: f090f0d0eea9666a96702b29bc9a64cbabee85c5
change-id: 20231128-alice-mm-bc533456cee8

Best regards,
Alice Ryhl <aliceryhl@xxxxxxxxxx>