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Diffstat (limited to 'rust/helpers.c')
| -rw-r--r-- | rust/helpers.c | 51 |
1 files changed, 0 insertions, 51 deletions
diff --git a/rust/helpers.c b/rust/helpers.c deleted file mode 100644 index b4f15eee2ffd..000000000000 --- a/rust/helpers.c +++ /dev/null @@ -1,51 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * Non-trivial C macros cannot be used in Rust. Similarly, inlined C functions - * cannot be called either. This file explicitly creates functions ("helpers") - * that wrap those so that they can be called from Rust. - * - * Even though Rust kernel modules should never use directly the bindings, some - * of these helpers need to be exported because Rust generics and inlined - * functions may not get their code generated in the crate where they are - * defined. Other helpers, called from non-inline functions, may not be - * exported, in principle. However, in general, the Rust compiler does not - * guarantee codegen will be performed for a non-inline function either. - * Therefore, this file exports all the helpers. In the future, this may be - * revisited to reduce the number of exports after the compiler is informed - * about the places codegen is required. - * - * All symbols are exported as GPL-only to guarantee no GPL-only feature is - * accidentally exposed. - */ - -#include <linux/bug.h> -#include <linux/build_bug.h> - -__noreturn void rust_helper_BUG(void) -{ - BUG(); -} -EXPORT_SYMBOL_GPL(rust_helper_BUG); - -/* - * We use `bindgen`'s `--size_t-is-usize` option to bind the C `size_t` type - * as the Rust `usize` type, so we can use it in contexts where Rust - * expects a `usize` like slice (array) indices. `usize` is defined to be - * the same as C's `uintptr_t` type (can hold any pointer) but not - * necessarily the same as `size_t` (can hold the size of any single - * object). Most modern platforms use the same concrete integer type for - * both of them, but in case we find ourselves on a platform where - * that's not true, fail early instead of risking ABI or - * integer-overflow issues. - * - * If your platform fails this assertion, it means that you are in - * danger of integer-overflow bugs (even if you attempt to remove - * `--size_t-is-usize`). It may be easiest to change the kernel ABI on - * your platform such that `size_t` matches `uintptr_t` (i.e., to increase - * `size_t`, because `uintptr_t` has to be at least as big as `size_t`). - */ -static_assert( - sizeof(size_t) == sizeof(uintptr_t) && - __alignof__(size_t) == __alignof__(uintptr_t), - "Rust code expects C `size_t` to match Rust `usize`" -); |
