Implementation for Aarch64 TME intrinsics

Author: vertexclique

crates/core_arch/src/aarch64/mod.rs

@@ -15,6 +15,9 @@ pub use self::neon::*;
 mod crypto;
 pub use self::crypto::*;
 
+mod tme;
+pub use self::tme::*;
+
 mod crc;
 pub use self::crc::*;
 

crates/core_arch/src/aarch64/tme.rs

@@ -0,0 +1,124 @@
+//! ARM's Transactional Memory Extensions (TME).
+//!
+//! This CPU feature is available on Aarch64 – ARMv8-A arch. onwards.
+//! This feature is in the non-neon feature set. TME specific vendor documentation can
+//! be found [TME Intrinsics Introduction][tme_intrinsics_intro].
+//!
+//! The reference is [ACLE Q4 2019][acle_q4_2019_ref].
+//!
+//! ACLE has a section for TME extensions and state masks for aborts and failure codes.
+//! In addition to that [LLVM Aarch64 Intrinsics][llvm_aarch64_int] are
+//! self explanatory for what needs to be exported.
+//!
+//! [acle_q4_2019_ref]: https://static.docs.arm.com/101028/0010/ACLE_2019Q4_release-0010.pdf
+//! [tme_intrinsics_intro]: https://developer.arm.com/docs/101028/0010/transactional-memory-extension-tme-intrinsics
+//! [llvm_aarch64_int]: https://github.com/llvm/llvm-project/commit/a36d31478c182903523e04eb271bbf102bfab2cc#diff-ff24e1c35f4d54f1110ce5d90c709319R626-R646
+
+#[cfg(test)]
+use stdarch_test::assert_instr;
+
+extern "C" {
+    #[link_name = "llvm.aarch64.tstart"]
+    fn aarch64_tstart() -> i32;
+    #[link_name = "llvm.aarch64.tcommit"]
+    fn aarch64_tcommit() -> ();
+    #[link_name = "llvm.aarch64.tcancel"]
+    fn aarch64_tcancel(imm0: i64) -> ();
+    #[link_name = "llvm.aarch64.ttest"]
+    fn aarch64_ttest() -> i32;
+}
+
+/// Transaction successfully started.
+pub const _TMSTART_SUCCESS: u32 = 0x00_u32;
+
+/// Extraction mask for failure reason
+pub const _TMFAILURE_REASON: u32 = 0x00007FFF_u32;
+
+/// Transaction retry is possible.
+pub const _TMFAILURE_RTRY: u32 = 1 << 15;
+
+/// Transaction cancelled.
+pub const _TMFAILURE_CNCL: u32 = 1 << 16;
+
+/// Transaction cancelled due to high memory usage.
+pub const _TMFAILURE_MEM: u32 = 1 << 17;
+
+///
+pub const _TMFAILURE_IMP: u32 = 1 << 18;
+
+///
+pub const _TMFAILURE_ERR: u32 = 1 << 19;
+
+///
+pub const _TMFAILURE_SIZE: u32 = 1 << 20;
+
+/// Transaction abort in a inner nested transaction.
+pub const _TMFAILURE_NEST: u32 = 1 << 21;
+
+/// Transaction abort due to a debug trap.
+pub const _TMFAILURE_DBG: u32 = 1 << 22;
+
+///
+pub const _TMFAILURE_INT: u32 = 1 << 23;
+
+///
+pub const _TMFAILURE_TRIVIAL: u32 = 1 << 24;
+
+
+/// Starts a new transaction. When the transaction starts successfully the return value is 0.
+/// If the transaction fails, all state modifications are discarded and a cause of the failure
+/// is encoded in the return value.
+///
+/// [ARM TME Intrinsics](https://developer.arm.com/docs/101028/0010/transactional-memory-extension-tme-intrinsics).
+#[inline]
+#[target_feature(enable = "tme")]
+#[cfg_attr(test, assert_instr(tstart))]
+pub unsafe fn __tstart() -> u32 {
+    aarch64_tstart() as _
+}
+
+/// Commits the current transaction. For a nested transaction, the only effect is that the
+/// transactional nesting depth is decreased. For an outer transaction, the state modifications
+/// performed transactionally are committed to the architectural state.
+///
+/// [ARM TME Intrinsics](https://developer.arm.com/docs/101028/0010/transactional-memory-extension-tme-intrinsics).
+#[inline]
+#[target_feature(enable = "tme")]
+#[cfg_attr(test, assert_instr(tcommit))]
+pub unsafe fn __tcommit() {
+    aarch64_tcommit()
+}
+
+/// Cancels the current transaction and discards all state modifications that were performed transactionally.
+///
+/// [ARM TME Intrinsics](https://developer.arm.com/docs/101028/0010/transactional-memory-extension-tme-intrinsics).
+#[inline]
+#[target_feature(enable = "tme")]
+#[cfg_attr(test, assert_instr(tcancel, imm0 = 0x0))]
+#[rustc_args_required_const(0)]
+pub unsafe fn __tcancel(imm0: u32) {
+    macro_rules! call {
+        ($imm0:expr) => {
+            aarch64_tcancel($imm0)
+        };
+    }
+    constify_imm8!(imm0, call)
+}
+
+/// Tests if executing inside a transaction. If no transaction is currently executing,
+/// the return value is 0. Otherwise, this intrinsic returns the depth of the transaction.
+///
+/// [ARM TME Intrinsics](https://developer.arm.com/docs/101028/0010/transactional-memory-extension-tme-intrinsics).
+#[inline]
+#[target_feature(enable = "tme")]
+#[cfg_attr(test, assert_instr(ttest))]
+pub unsafe fn __ttest() -> u32 {
+    aarch64_ttest() as _
+}
+
+/// Encodes cancellation reason, which is the parameter passed to [`__tcancel`]
+/// Takes cancellation reason flags and retry-ability.
+#[inline]
+pub const fn _tcancel_code(reason: u32, retryable: bool) -> u32 {
+    (retryable as i32) << 15 | (reason & _TMFAILURE_REASON)
+}

crates/std_detect/tests/cpu-detection.rs

@@ -45,6 +45,7 @@ fn aarch64_linux() {
     println!("rdm: {}", is_aarch64_feature_detected!("rdm"));
     println!("rcpc: {}", is_aarch64_feature_detected!("rcpc"));
     println!("dotprod: {}", is_aarch64_feature_detected!("dotprod"));
+    println!("tme: {}", is_aarch64_feature_detected!("tme"));
 }
 
 #[test]