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Diffstat (limited to 'rust/kernel/kunit.rs')
| -rw-r--r-- | rust/kernel/kunit.rs | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs new file mode 100644 index 000000000000..722655b2d62d --- /dev/null +++ b/rust/kernel/kunit.rs @@ -0,0 +1,163 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! KUnit-based macros for Rust unit tests. +//! +//! C header: [`include/kunit/test.h`](../../../../../include/kunit/test.h) +//! +//! Reference: <https://docs.kernel.org/dev-tools/kunit/index.html> + +use core::{ffi::c_void, fmt}; + +/// Prints a KUnit error-level message. +/// +/// Public but hidden since it should only be used from KUnit generated code. +#[doc(hidden)] +pub fn err(args: fmt::Arguments<'_>) { + // SAFETY: The format string is null-terminated and the `%pA` specifier matches the argument we + // are passing. + #[cfg(CONFIG_PRINTK)] + unsafe { + bindings::_printk( + b"\x013%pA\0".as_ptr() as _, + &args as *const _ as *const c_void, + ); + } +} + +/// Prints a KUnit info-level message. +/// +/// Public but hidden since it should only be used from KUnit generated code. +#[doc(hidden)] +pub fn info(args: fmt::Arguments<'_>) { + // SAFETY: The format string is null-terminated and the `%pA` specifier matches the argument we + // are passing. + #[cfg(CONFIG_PRINTK)] + unsafe { + bindings::_printk( + b"\x016%pA\0".as_ptr() as _, + &args as *const _ as *const c_void, + ); + } +} + +/// Asserts that a boolean expression is `true` at runtime. +/// +/// Public but hidden since it should only be used from generated tests. +/// +/// Unlike the one in `core`, this one does not panic; instead, it is mapped to the KUnit +/// facilities. See [`assert!`] for more details. +#[doc(hidden)] +#[macro_export] +macro_rules! kunit_assert { + ($name:literal, $file:literal, $diff:expr, $condition:expr $(,)?) => { + 'out: { + // Do nothing if the condition is `true`. + if $condition { + break 'out; + } + + static FILE: &'static $crate::str::CStr = $crate::c_str!($file); + static LINE: i32 = core::line!() as i32 - $diff; + static CONDITION: &'static $crate::str::CStr = $crate::c_str!(stringify!($condition)); + + // SAFETY: FFI call without safety requirements. + let kunit_test = unsafe { $crate::bindings::kunit_get_current_test() }; + if kunit_test.is_null() { + // The assertion failed but this task is not running a KUnit test, so we cannot call + // KUnit, but at least print an error to the kernel log. This may happen if this + // macro is called from an spawned thread in a test (see + // `scripts/rustdoc_test_gen.rs`) or if some non-test code calls this macro by + // mistake (it is hidden to prevent that). + // + // This mimics KUnit's failed assertion format. + $crate::kunit::err(format_args!( + " # {}: ASSERTION FAILED at {FILE}:{LINE}\n", + $name + )); + $crate::kunit::err(format_args!( + " Expected {CONDITION} to be true, but is false\n" + )); + $crate::kunit::err(format_args!( + " Failure not reported to KUnit since this is a non-KUnit task\n" + )); + break 'out; + } + + #[repr(transparent)] + struct Location($crate::bindings::kunit_loc); + + #[repr(transparent)] + struct UnaryAssert($crate::bindings::kunit_unary_assert); + + // SAFETY: There is only a static instance and in that one the pointer field points to + // an immutable C string. + unsafe impl Sync for Location {} + + // SAFETY: There is only a static instance and in that one the pointer field points to + // an immutable C string. + unsafe impl Sync for UnaryAssert {} + + static LOCATION: Location = Location($crate::bindings::kunit_loc { + file: FILE.as_char_ptr(), + line: LINE, + }); + static ASSERTION: UnaryAssert = UnaryAssert($crate::bindings::kunit_unary_assert { + assert: $crate::bindings::kunit_assert {}, + condition: CONDITION.as_char_ptr(), + expected_true: true, + }); + + // SAFETY: + // - FFI call. + // - The `kunit_test` pointer is valid because we got it from + // `kunit_get_current_test()` and it was not null. This means we are in a KUnit + // test, and that the pointer can be passed to KUnit functions and assertions. + // - The string pointers (`file` and `condition` above) point to null-terminated + // strings since they are `CStr`s. + // - The function pointer (`format`) points to the proper function. + // - The pointers passed will remain valid since they point to `static`s. + // - The format string is allowed to be null. + // - There are, however, problems with this: first of all, this will end up stopping + // the thread, without running destructors. While that is problematic in itself, + // it is considered UB to have what is effectively a forced foreign unwind + // with `extern "C"` ABI. One could observe the stack that is now gone from + // another thread. We should avoid pinning stack variables to prevent library UB, + // too. For the moment, given that test failures are reported immediately before the + // next test runs, that test failures should be fixed and that KUnit is explicitly + // documented as not suitable for production environments, we feel it is reasonable. + unsafe { + $crate::bindings::__kunit_do_failed_assertion( + kunit_test, + core::ptr::addr_of!(LOCATION.0), + $crate::bindings::kunit_assert_type_KUNIT_ASSERTION, + core::ptr::addr_of!(ASSERTION.0.assert), + Some($crate::bindings::kunit_unary_assert_format), + core::ptr::null(), + ); + } + + // SAFETY: FFI call; the `test` pointer is valid because this hidden macro should only + // be called by the generated documentation tests which forward the test pointer given + // by KUnit. + unsafe { + $crate::bindings::__kunit_abort(kunit_test); + } + } + }; +} + +/// Asserts that two expressions are equal to each other (using [`PartialEq`]). +/// +/// Public but hidden since it should only be used from generated tests. +/// +/// Unlike the one in `core`, this one does not panic; instead, it is mapped to the KUnit +/// facilities. See [`assert!`] for more details. +#[doc(hidden)] +#[macro_export] +macro_rules! kunit_assert_eq { + ($name:literal, $file:literal, $diff:expr, $left:expr, $right:expr $(,)?) => {{ + // For the moment, we just forward to the expression assert because, for binary asserts, + // KUnit supports only a few types (e.g. integers). + $crate::kunit_assert!($name, $file, $diff, $left == $right); + }}; +} |