cpufeatures: Add support for LoongArch64 (#955)

cpufeatures/Cargo.toml

@@ -2,8 +2,8 @@
 name = "cpufeatures"
 version = "0.2.9"
 description = """
-Lightweight runtime CPU feature detection for x86/x86_64 and aarch64 with
-no_std support and support for mobile targets including Android and iOS
+Lightweight runtime CPU feature detection for aarch64, loongarch64, and x86/x86_64 targets, 
+with no_std support and support for mobile targets including Android and iOS
 """
 authors = ["RustCrypto Developers"]
 license = "MIT OR Apache-2.0"
@@ -15,10 +15,13 @@ edition = "2018"
 readme = "README.md"
 
 [target.'cfg(all(target_arch = "aarch64", target_vendor = "apple"))'.dependencies]
-libc = "0.2.95"
+libc = "0.2.149"
 
 [target.'cfg(all(target_arch = "aarch64", target_os = "linux"))'.dependencies]
-libc = "0.2.95"
+libc = "0.2.149"
+
+[target.'cfg(all(target_arch = "loongarch64", target_os = "linux"))'.dependencies]
+libc = "0.2.149"
 
 [target.aarch64-linux-android.dependencies]
-libc = "0.2.95"
+libc = "0.2.149"

cpufeatures/README.md

@@ -7,7 +7,7 @@
 [![Project Chat][chat-image]][chat-link]
 [![Build Status][build-image]][build-link]
 
-Lightweight and efficient runtime CPU feature detection for `aarch64` and
+Lightweight and efficient runtime CPU feature detection for `aarch64`, `loongarch64`, and
 `x86`/`x86_64` targets.
 
 Supports `no_std` as well as mobile targets including iOS and Android,
@@ -31,6 +31,26 @@ Target features:
 - `sha2`*
 - `sha3`*
 
+## `loongarch64`
+
+Linux only (LoongArch64 does not support OS-independent feature detection)
+
+Target features:
+
+- `lam`*
+- `ual`*
+- `fpu`*
+- `lsx`*
+- `lasx`*
+- `crc32`*
+- `complex`*
+- `crypto`*
+- `lvz`*
+- `lbt.x86`*
+- `lbt.arm`*
+- `lbt.mips`*
+- `ptw`*
+
 ## `x86`/`x86_64`
 
 OS independent and `no_std`-friendly

cpufeatures/src/lib.rs

@@ -18,6 +18,26 @@
 //! - `sha2`*
 //! - `sha3`*
 //!
+//! ## `loongarch64`
+//!
+//! Linux only (LoongArch64 does not support OS-independent feature detection)
+//!
+//! Target features:
+//!
+//! - `lam`*
+//! - `ual`*
+//! - `fpu`*
+//! - `lsx`*
+//! - `lasx`*
+//! - `crc32`*
+//! - `complex`*
+//! - `crypto`*
+//! - `lvz`*
+//! - `lbt.x86`*
+//! - `lbt.arm`*
+//! - `lbt.mips`*
+//! - `ptw`*
+//!
 //! ## `x86`/`x86_64`
 //!
 //! OS independent and `no_std`-friendly
@@ -107,15 +127,25 @@
 #[doc(hidden)]
 pub mod aarch64;
 
+#[cfg(not(miri))]
+#[cfg(target_arch = "loongarch64")]
+#[doc(hidden)]
+pub mod loongarch64;
+
 #[cfg(not(miri))]
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
 mod x86;
 
 #[cfg(miri)]
 mod miri;
 
-#[cfg(not(any(target_arch = "aarch64", target_arch = "x86", target_arch = "x86_64")))]
-compile_error!("This crate works only on `aarch64`, `x86`, and `x86-64` targets.");
+#[cfg(not(any(
+    target_arch = "aarch64",
+    target_arch = "loongarch64",
+    target_arch = "x86",
+    target_arch = "x86_64"
+)))]
+compile_error!("This crate works only on `aarch64`, `loongarch64`, `x86`, and `x86-64` targets.");
 
 /// Create module with CPU feature detection code.
 #[macro_export]

cpufeatures/src/loongarch64.rs

@@ -0,0 +1,106 @@
+//! LoongArch64 CPU feature detection support.
+//!
+//! This implementation relies on OS-specific APIs for feature detection.
+
+// Evaluate the given `$body` expression any of the supplied target features
+// are not enabled. Otherwise returns true.
+#[macro_export]
+#[doc(hidden)]
+macro_rules! __unless_target_features {
+    ($($tf:tt),+ => $body:expr ) => {
+        {
+            #[cfg(not(all($(target_feature=$tf,)*)))]
+            $body
+
+            #[cfg(all($(target_feature=$tf,)*))]
+            true
+        }
+    };
+}
+
+// Linux runtime detection of target CPU features using `getauxval`.
+#[cfg(target_os = "linux")]
+#[macro_export]
+#[doc(hidden)]
+macro_rules! __detect_target_features {
+    ($($tf:tt),+) => {{
+        let hwcaps = $crate::loongarch64::getauxval_hwcap();
+        $($crate::check!(hwcaps, $tf) & )+ true
+    }};
+}
+
+/// Linux helper function for calling `getauxval` to get `AT_HWCAP`.
+#[cfg(target_os = "linux")]
+pub fn getauxval_hwcap() -> u64 {
+    unsafe { libc::getauxval(libc::AT_HWCAP) }
+}
+
+// Linux `expand_check_macro`
+#[cfg(target_os = "linux")]
+macro_rules! __expand_check_macro {
+    ($(($name:tt, $hwcap:ident)),* $(,)?) => {
+        #[macro_export]
+        #[doc(hidden)]
+        macro_rules! check {
+            $(
+                ($hwcaps:expr, $name) => {
+                    (($hwcaps & $crate::loongarch64::hwcaps::$hwcap) != 0)
+                };
+            )*
+        }
+    };
+}
+
+// Linux `expand_check_macro`
+#[cfg(target_os = "linux")]
+__expand_check_macro! {
+    ("cpucfg",   CPUCFG),   // Enable CPUCFG support.
+    ("lam",      LAM),      // Enable LAM support.
+    ("ual",      UAL),      // Enable UAL support.
+    ("fpu",      FPU),      // Enable FPU support.
+    ("lsx",      LSX),      // Enable LSX support.
+    ("lasx",     LASX),     // Enable LASX support.
+    ("crc32",    CRC32),    // Enable CRC32 support.
+    ("complex",  COMPLEX),  // Enable COMPLEX support.
+    ("crypto",   CRYPTO),   // Enable CRYPTO support.
+    ("lvz",      LVZ),      // Enable LVZ support.
+    ("lbt.x86",  LBT_X86),  // Enable LBT_X86 support.
+    ("lbt.arm",  LBT_ARM),  // Enable LBT_ARM support.
+    ("lbt.mips", LBT_MIPS), // Enable LBT_MIPS support.
+    ("ptw",      PTW),      // Enable PTW support.
+}
+
+/// Linux hardware capabilities mapped to target features.
+///
+/// Note that LLVM target features are coarser grained than what Linux supports
+/// and imply more capabilities under each feature. This module attempts to
+/// provide that mapping accordingly.
+#[cfg(target_os = "linux")]
+pub mod hwcaps {
+    use libc::c_ulong;
+
+    pub const CPUCFG: c_ulong = libc::HWCAP_CPUCFG;
+    pub const LAM: c_ulong = libc::HWCAP_LAM;
+    pub const UAL: c_ulong = libc::HWCAP_UAL;
+    pub const FPU: c_ulong = libc::HWCAP_FPU;
+    pub const LSX: c_ulong = libc::HWCAP_LSX;
+    pub const LASX: c_ulong = libc::HWCAP_LASX;
+    pub const CRC32: c_ulong = libc::HWCAP_CRC32;
+    pub const COMPLEX: c_ulong = libc::HWCAP_COMPLEX;
+    pub const CRYPTO: c_ulong = libc::HWCAP_CRYPTO;
+    pub const LVZ: c_ulong = libc::HWCAP_LVZ;
+    pub const LBT_X86: c_ulong = libc::HWCAP_LBT_X86;
+    pub const LBT_ARM: c_ulong = libc::HWCAP_LBT_ARM;
+    pub const LBT_MIPS: c_ulong = libc::HWCAP_LBT_MIPS;
+    pub const PTW: c_ulong = libc::HWCAP_PTW;
+}
+
+// On other targets, runtime CPU feature detection is unavailable
+#[cfg(not(target_os = "linux"))]
+#[macro_export]
+#[doc(hidden)]
+macro_rules! __detect_target_features {
+    ($($tf:tt),+) => {
+        false
+    };
+}

cpufeatures/tests/loongarch64.rs

@@ -0,0 +1,20 @@
+//! LoongArch64 tests
+
+#![cfg(target_arch = "loongarch64")]
+
+cpufeatures::new!(
+    lacaps, "cpucfg", "lam", "ual", "fpu", "lsx", "lasx", "crc32", "complex", "crypto", "lvz",
+    "lbt.x86", "lbt.arm", "lbt.mips", "ptw"
+);
+
+#[test]
+fn init() {
+    let token: lacaps::InitToken = lacaps::init();
+    assert_eq!(token.get(), lacaps::get());
+}
+
+#[test]
+fn init_get() {
+    let (token, val) = lacaps::init_get();
+    assert_eq!(val, token.get());
+}