From 5a888c28e3b4ff6f54a53fca33951537d135e7f1 Mon Sep 17 00:00:00 2001 From: Danilo Krummrich Date: Fri, 4 Oct 2024 17:41:11 +0200 Subject: rust: alloc: add module `allocator_test` `Allocator`s, such as `Kmalloc`, will be used by e.g. `Box` and `Vec` in subsequent patches, and hence this dependency propagates throughout the whole kernel. Add the `allocator_test` module that provides an empty implementation for all `Allocator`s in the kernel, such that we don't break the `rusttest` make target in subsequent patches. Reviewed-by: Alice Ryhl Reviewed-by: Benno Lossin Reviewed-by: Gary Guo Signed-off-by: Danilo Krummrich Link: https://lore.kernel.org/r/20241004154149.93856-8-dakr@kernel.org [ Added missing `_old_layout` parameter as discussed. - Miguel ] Signed-off-by: Miguel Ojeda --- rust/kernel/alloc/allocator_test.rs | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) create mode 100644 rust/kernel/alloc/allocator_test.rs (limited to 'rust/kernel/alloc/allocator_test.rs') diff --git a/rust/kernel/alloc/allocator_test.rs b/rust/kernel/alloc/allocator_test.rs new file mode 100644 index 000000000000..c5d325506f0c --- /dev/null +++ b/rust/kernel/alloc/allocator_test.rs @@ -0,0 +1,20 @@ +// SPDX-License-Identifier: GPL-2.0 + +#![allow(missing_docs)] + +use super::{AllocError, Allocator, Flags}; +use core::alloc::Layout; +use core::ptr::NonNull; + +pub struct Kmalloc; + +unsafe impl Allocator for Kmalloc { + unsafe fn realloc( + _ptr: Option>, + _layout: Layout, + _old_layout: Layout, + _flags: Flags, + ) -> Result, AllocError> { + panic!(); + } +} -- cgit From 61c004781d6b928443052e7a6cf84b35d4f61401 Mon Sep 17 00:00:00 2001 From: Danilo Krummrich Date: Fri, 4 Oct 2024 17:41:12 +0200 Subject: rust: alloc: implement `Vmalloc` allocator Implement `Allocator` for `Vmalloc`, the kernel's virtually contiguous allocator, typically used for larger objects, (much) larger than page size. All memory allocations made with `Vmalloc` end up in `vrealloc()`. Reviewed-by: Alice Ryhl Reviewed-by: Benno Lossin Reviewed-by: Gary Guo Signed-off-by: Danilo Krummrich Link: https://lore.kernel.org/r/20241004154149.93856-9-dakr@kernel.org Signed-off-by: Miguel Ojeda --- rust/kernel/alloc/allocator_test.rs | 1 + 1 file changed, 1 insertion(+) (limited to 'rust/kernel/alloc/allocator_test.rs') diff --git a/rust/kernel/alloc/allocator_test.rs b/rust/kernel/alloc/allocator_test.rs index c5d325506f0c..32a1450c4d39 100644 --- a/rust/kernel/alloc/allocator_test.rs +++ b/rust/kernel/alloc/allocator_test.rs @@ -7,6 +7,7 @@ use core::alloc::Layout; use core::ptr::NonNull; pub struct Kmalloc; +pub type Vmalloc = Kmalloc; unsafe impl Allocator for Kmalloc { unsafe fn realloc( -- cgit From 8362c2608ba1be635ffa22a256dfcfe51c6238cc Mon Sep 17 00:00:00 2001 From: Danilo Krummrich Date: Fri, 4 Oct 2024 17:41:13 +0200 Subject: rust: alloc: implement `KVmalloc` allocator Implement `Allocator` for `KVmalloc`, an `Allocator` that tries to allocate memory with `kmalloc` first and, on failure, falls back to `vmalloc`. All memory allocations made with `KVmalloc` end up in `kvrealloc_noprof()`; all frees in `kvfree()`. Reviewed-by: Alice Ryhl Reviewed-by: Benno Lossin Reviewed-by: Gary Guo Signed-off-by: Danilo Krummrich Link: https://lore.kernel.org/r/20241004154149.93856-10-dakr@kernel.org [ Reworded typo. - Miguel ] Signed-off-by: Miguel Ojeda --- rust/kernel/alloc/allocator_test.rs | 1 + 1 file changed, 1 insertion(+) (limited to 'rust/kernel/alloc/allocator_test.rs') diff --git a/rust/kernel/alloc/allocator_test.rs b/rust/kernel/alloc/allocator_test.rs index 32a1450c4d39..bd0cbcd93e52 100644 --- a/rust/kernel/alloc/allocator_test.rs +++ b/rust/kernel/alloc/allocator_test.rs @@ -8,6 +8,7 @@ use core::ptr::NonNull; pub struct Kmalloc; pub type Vmalloc = Kmalloc; +pub type KVmalloc = Kmalloc; unsafe impl Allocator for Kmalloc { unsafe fn realloc( -- cgit From dd09538fb4093176a818fcecd45114430cc5840f Mon Sep 17 00:00:00 2001 From: Danilo Krummrich Date: Fri, 4 Oct 2024 17:41:29 +0200 Subject: rust: alloc: implement `Cmalloc` in module allocator_test So far the kernel's `Box` and `Vec` types can't be used by userspace test cases, since all users of those types (e.g. `CString`) use kernel allocators for instantiation. In order to allow userspace test cases to make use of such types as well, implement the `Cmalloc` allocator within the allocator_test module and type alias all kernel allocators to `Cmalloc`. The `Cmalloc` allocator uses libc's `realloc()` function as allocator backend. Reviewed-by: Benno Lossin Reviewed-by: Gary Guo Signed-off-by: Danilo Krummrich Link: https://lore.kernel.org/r/20241004154149.93856-26-dakr@kernel.org [ Removed the temporary `allow(dead_code)` as discussed in the list and fixed typo, added backticks. - Miguel ] Signed-off-by: Miguel Ojeda --- rust/kernel/alloc/allocator_test.rs | 89 +++++++++++++++++++++++++++++++++---- 1 file changed, 81 insertions(+), 8 deletions(-) (limited to 'rust/kernel/alloc/allocator_test.rs') diff --git a/rust/kernel/alloc/allocator_test.rs b/rust/kernel/alloc/allocator_test.rs index bd0cbcd93e52..54ca85964d4a 100644 --- a/rust/kernel/alloc/allocator_test.rs +++ b/rust/kernel/alloc/allocator_test.rs @@ -1,22 +1,95 @@ // SPDX-License-Identifier: GPL-2.0 +//! So far the kernel's `Box` and `Vec` types can't be used by userspace test cases, since all users +//! of those types (e.g. `CString`) use kernel allocators for instantiation. +//! +//! In order to allow userspace test cases to make use of such types as well, implement the +//! `Cmalloc` allocator within the allocator_test module and type alias all kernel allocators to +//! `Cmalloc`. The `Cmalloc` allocator uses libc's `realloc()` function as allocator backend. + #![allow(missing_docs)] -use super::{AllocError, Allocator, Flags}; +use super::{flags::*, AllocError, Allocator, Flags}; use core::alloc::Layout; +use core::cmp; +use core::ptr; use core::ptr::NonNull; -pub struct Kmalloc; +/// The userspace allocator based on libc. +pub struct Cmalloc; + +pub type Kmalloc = Cmalloc; pub type Vmalloc = Kmalloc; pub type KVmalloc = Kmalloc; -unsafe impl Allocator for Kmalloc { +extern "C" { + #[link_name = "aligned_alloc"] + fn libc_aligned_alloc(align: usize, size: usize) -> *mut core::ffi::c_void; + + #[link_name = "free"] + fn libc_free(ptr: *mut core::ffi::c_void); +} + +// SAFETY: +// - memory remains valid until it is explicitly freed, +// - passing a pointer to a valid memory allocation created by this `Allocator` is always OK, +// - `realloc` provides the guarantees as provided in the `# Guarantees` section. +unsafe impl Allocator for Cmalloc { unsafe fn realloc( - _ptr: Option>, - _layout: Layout, - _old_layout: Layout, - _flags: Flags, + ptr: Option>, + layout: Layout, + old_layout: Layout, + flags: Flags, ) -> Result, AllocError> { - panic!(); + let src = match ptr { + Some(src) => { + if old_layout.size() == 0 { + ptr::null_mut() + } else { + src.as_ptr() + } + } + None => ptr::null_mut(), + }; + + if layout.size() == 0 { + // SAFETY: `src` is either NULL or was previously allocated with this `Allocator` + unsafe { libc_free(src.cast()) }; + + return Ok(NonNull::slice_from_raw_parts( + crate::alloc::dangling_from_layout(layout), + 0, + )); + } + + // SAFETY: Returns either NULL or a pointer to a memory allocation that satisfies or + // exceeds the given size and alignment requirements. + let dst = unsafe { libc_aligned_alloc(layout.align(), layout.size()) } as *mut u8; + let dst = NonNull::new(dst).ok_or(AllocError)?; + + if flags.contains(__GFP_ZERO) { + // SAFETY: The preceding calls to `libc_aligned_alloc` and `NonNull::new` + // guarantee that `dst` points to memory of at least `layout.size()` bytes. + unsafe { dst.as_ptr().write_bytes(0, layout.size()) }; + } + + if !src.is_null() { + // SAFETY: + // - `src` has previously been allocated with this `Allocator`; `dst` has just been + // newly allocated, hence the memory regions do not overlap. + // - both` src` and `dst` are properly aligned and valid for reads and writes + unsafe { + ptr::copy_nonoverlapping( + src, + dst.as_ptr(), + cmp::min(layout.size(), old_layout.size()), + ) + }; + } + + // SAFETY: `src` is either NULL or was previously allocated with this `Allocator` + unsafe { libc_free(src.cast()) }; + + Ok(NonNull::slice_from_raw_parts(dst, layout.size())) } } -- cgit From d072acda4862f095ec9056979b654cc06a22cc68 Mon Sep 17 00:00:00 2001 From: Gary Guo Date: Fri, 13 Sep 2024 22:29:23 +0100 Subject: rust: use custom FFI integer types Currently FFI integer types are defined in libcore. This commit creates the `ffi` crate and asks bindgen to use that crate for FFI integer types instead of `core::ffi`. This commit is preparatory and no type changes are made in this commit yet. Signed-off-by: Gary Guo Link: https://lore.kernel.org/r/20240913213041.395655-4-gary@garyguo.net [ Added `rustdoc`, `rusttest` and KUnit tests support. Rebased on top of `rust-next` (e.g. migrated more `core::ffi` cases). Reworded crate docs slightly and formatted. - Miguel ] Signed-off-by: Miguel Ojeda --- rust/kernel/alloc/allocator_test.rs | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'rust/kernel/alloc/allocator_test.rs') diff --git a/rust/kernel/alloc/allocator_test.rs b/rust/kernel/alloc/allocator_test.rs index 54ca85964d4a..e3240d16040b 100644 --- a/rust/kernel/alloc/allocator_test.rs +++ b/rust/kernel/alloc/allocator_test.rs @@ -24,10 +24,10 @@ pub type KVmalloc = Kmalloc; extern "C" { #[link_name = "aligned_alloc"] - fn libc_aligned_alloc(align: usize, size: usize) -> *mut core::ffi::c_void; + fn libc_aligned_alloc(align: usize, size: usize) -> *mut crate::ffi::c_void; #[link_name = "free"] - fn libc_free(ptr: *mut core::ffi::c_void); + fn libc_free(ptr: *mut crate::ffi::c_void); } // SAFETY: -- cgit