From 1bae8729e50a900f41e9a1c17ae81113e4cf62b8 Mon Sep 17 00:00:00 2001 From: Gary Guo Date: Fri, 13 Sep 2024 22:29:24 +0100 Subject: rust: map `long` to `isize` and `char` to `u8` The following FFI types are replaced compared to `core::ffi`: 1. `char` type is now always mapped to `u8`, since kernel uses `-funsigned-char` on the C code. `core::ffi` maps it to platform default ABI, which can be either signed or unsigned. 2. `long` is now always mapped to `isize`. It's very common in the kernel to use `long` to represent a pointer-sized integer, and in fact `intptr_t` is a typedef of `long` in the kernel. Enforce this mapping rather than mapping to `i32/i64` depending on platform can save us a lot of unnecessary casts. Signed-off-by: Gary Guo Reviewed-by: Alice Ryhl Link: https://lore.kernel.org/r/20240913213041.395655-5-gary@garyguo.net [ Moved `uaccess` changes from the next commit, since they were irrefutable patterns that Rust >= 1.82.0 warns about. Reworded slightly and reformatted a few documentation comments. Rebased on top of `rust-next`. Added the removal of two casts to avoid Clippy warnings. - Miguel ] Signed-off-by: Miguel Ojeda --- rust/kernel/uaccess.rs | 27 +++++++-------------------- 1 file changed, 7 insertions(+), 20 deletions(-) (limited to 'rust/kernel/uaccess.rs') diff --git a/rust/kernel/uaccess.rs b/rust/kernel/uaccess.rs index 05b0b8d13b10..cc044924867b 100644 --- a/rust/kernel/uaccess.rs +++ b/rust/kernel/uaccess.rs @@ -8,7 +8,7 @@ use crate::{ alloc::Flags, bindings, error::Result, - ffi::{c_ulong, c_void}, + ffi::c_void, prelude::*, transmute::{AsBytes, FromBytes}, }; @@ -224,13 +224,9 @@ impl UserSliceReader { if len > self.length { return Err(EFAULT); } - let Ok(len_ulong) = c_ulong::try_from(len) else { - return Err(EFAULT); - }; - // SAFETY: `out_ptr` points into a mutable slice of length `len_ulong`, so we may write + // SAFETY: `out_ptr` points into a mutable slice of length `len`, so we may write // that many bytes to it. - let res = - unsafe { bindings::copy_from_user(out_ptr, self.ptr as *const c_void, len_ulong) }; + let res = unsafe { bindings::copy_from_user(out_ptr, self.ptr as *const c_void, len) }; if res != 0 { return Err(EFAULT); } @@ -259,9 +255,6 @@ impl UserSliceReader { if len > self.length { return Err(EFAULT); } - let Ok(len_ulong) = c_ulong::try_from(len) else { - return Err(EFAULT); - }; let mut out: MaybeUninit = MaybeUninit::uninit(); // SAFETY: The local variable `out` is valid for writing `size_of::()` bytes. // @@ -272,7 +265,7 @@ impl UserSliceReader { bindings::_copy_from_user( out.as_mut_ptr().cast::(), self.ptr as *const c_void, - len_ulong, + len, ) }; if res != 0 { @@ -335,12 +328,9 @@ impl UserSliceWriter { if len > self.length { return Err(EFAULT); } - let Ok(len_ulong) = c_ulong::try_from(len) else { - return Err(EFAULT); - }; - // SAFETY: `data_ptr` points into an immutable slice of length `len_ulong`, so we may read + // SAFETY: `data_ptr` points into an immutable slice of length `len`, so we may read // that many bytes from it. - let res = unsafe { bindings::copy_to_user(self.ptr as *mut c_void, data_ptr, len_ulong) }; + let res = unsafe { bindings::copy_to_user(self.ptr as *mut c_void, data_ptr, len) }; if res != 0 { return Err(EFAULT); } @@ -359,9 +349,6 @@ impl UserSliceWriter { if len > self.length { return Err(EFAULT); } - let Ok(len_ulong) = c_ulong::try_from(len) else { - return Err(EFAULT); - }; // SAFETY: The reference points to a value of type `T`, so it is valid for reading // `size_of::()` bytes. // @@ -372,7 +359,7 @@ impl UserSliceWriter { bindings::_copy_to_user( self.ptr as *mut c_void, (value as *const T).cast::(), - len_ulong, + len, ) }; if res != 0 { -- cgit v1.2.3 From c80dd3fc45d573458bc763d599d97c82cf5dc212 Mon Sep 17 00:00:00 2001 From: Filipe Xavier Date: Tue, 7 Jan 2025 16:25:39 -0300 Subject: rust: uaccess: generalize userSliceReader to support any Vec The UserSliceReader::read_all function is currently restricted to use only Vec with the kmalloc allocator. However, there is no reason for this limitation. This patch generalizes the function to accept any Vec regardless of the allocator used. There's a use-case for a KVVec in Binder to avoid maximum sizes for a certain array. Link: https://github.com/Rust-for-Linux/linux/issues/1136 Signed-off-by: Filipe Xavier Reviewed-by: Alice Ryhl Reviewed-by: Boqun Feng Link: https://lore.kernel.org/r/20250107-gen-userslice-readall-alloc-v2-1-d7fe4d19241a@gmail.com [ Reflowed and slightly reworded title. - Miguel ] Signed-off-by: Miguel Ojeda --- rust/kernel/uaccess.rs | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'rust/kernel/uaccess.rs') diff --git a/rust/kernel/uaccess.rs b/rust/kernel/uaccess.rs index cc044924867b..719b0a48ff55 100644 --- a/rust/kernel/uaccess.rs +++ b/rust/kernel/uaccess.rs @@ -5,7 +5,7 @@ //! C header: [`include/linux/uaccess.h`](srctree/include/linux/uaccess.h) use crate::{ - alloc::Flags, + alloc::{Allocator, Flags}, bindings, error::Result, ffi::c_void, @@ -127,7 +127,7 @@ impl UserSlice { /// Reads the entirety of the user slice, appending it to the end of the provided buffer. /// /// Fails with [`EFAULT`] if the read happens on a bad address. - pub fn read_all(self, buf: &mut KVec, flags: Flags) -> Result { + pub fn read_all(self, buf: &mut Vec, flags: Flags) -> Result { self.reader().read_all(buf, flags) } @@ -281,7 +281,7 @@ impl UserSliceReader { /// Reads the entirety of the user slice, appending it to the end of the provided buffer. /// /// Fails with [`EFAULT`] if the read happens on a bad address. - pub fn read_all(mut self, buf: &mut KVec, flags: Flags) -> Result { + pub fn read_all(mut self, buf: &mut Vec, flags: Flags) -> Result { let len = self.length; buf.reserve(len, flags)?; -- cgit v1.2.3