detect: Support run-time detection on aarch64 illumos

.github/.cspell/project-dictionary.txt

@@ -45,6 +45,7 @@ elems
 espup
 exynos
 getauxval
+getisax
 getpid
 gimli
 Halfword
@@ -116,6 +117,7 @@ RAII
 rcpc
 reentrancy
 revidr
+richlowe
 rsbegin
 rsend
 rsil

src/imp/atomic128/README.md

@@ -43,6 +43,7 @@ Here is the table of targets that support run-time CPU feature detection and the
 | aarch64     | netbsd               | sysctl          | all      | Enabled by default |
 | aarch64     | openbsd              | sysctl          | all      | Enabled by default |
 | aarch64     | macos                | sysctl          | all      | Currently only used in tests because FEAT_LSE and FEAT_LSE2 are always available at compile-time. |
+| aarch64     | illumos              | getisax         | lse, lse2 | Enabled by default |
 | aarch64     | windows              | IsProcessorFeaturePresent | lse | Enabled by default |
 | aarch64     | fuchsia              | zx_system_get_features | lse | Enabled by default |
 | powerpc64   | linux                | getauxval       | all      | Disabled by default |

src/imp/atomic128/aarch64.rs

@@ -113,6 +113,17 @@ mod detect;
 #[path = "detect/aarch64_aa64reg.rs"]
 mod detect;
 #[cfg(not(portable_atomic_no_outline_atomics))]
+#[cfg(any(
+    test,
+    not(all(
+        any(target_feature = "lse2", portable_atomic_target_feature = "lse2"),
+        any(target_feature = "lse", portable_atomic_target_feature = "lse"),
+    )),
+))]
+#[cfg(target_os = "illumos")]
+#[path = "detect/aarch64_illumos.rs"]
+mod detect;
+#[cfg(not(portable_atomic_no_outline_atomics))]
 #[cfg(any(test, not(any(target_feature = "lse", portable_atomic_target_feature = "lse"))))]
 #[cfg(target_os = "fuchsia")]
 #[path = "detect/aarch64_fuchsia.rs"]
@@ -174,6 +185,7 @@ macro_rules! debug_assert_lse {
                 target_os = "freebsd",
                 target_os = "netbsd",
                 target_os = "openbsd",
+                target_os = "illumos",
                 target_os = "fuchsia",
                 target_os = "windows",
             ),
@@ -210,6 +222,7 @@ macro_rules! debug_assert_lse2 {
                 target_os = "freebsd",
                 target_os = "netbsd",
                 target_os = "openbsd",
+                target_os = "illumos",
                 // These don't support detection of FEAT_LSE2.
                 // target_os = "fuchsia",
                 // target_os = "windows",
@@ -251,6 +264,7 @@ macro_rules! debug_assert_lse128 {
                 target_os = "freebsd",
                 target_os = "netbsd",
                 target_os = "openbsd",
+                target_os = "illumos",
                 // These don't support detection of FEAT_LSE128.
                 // target_os = "fuchsia",
                 // target_os = "windows",
@@ -292,6 +306,7 @@ macro_rules! debug_assert_rcpc3 {
                 target_os = "freebsd",
                 target_os = "netbsd",
                 target_os = "openbsd",
+                target_os = "illumos",
                 // These don't support detection of FEAT_LRCPC3.
                 // target_os = "fuchsia",
                 // target_os = "windows",
@@ -475,6 +490,7 @@ unsafe fn atomic_load(src: *mut u128, order: Ordering) -> u128 {
             target_os = "freebsd",
             target_os = "netbsd",
             target_os = "openbsd",
+            target_os = "illumos",
             // These don't support detection of FEAT_LSE2.
             // target_os = "fuchsia",
             // target_os = "windows",
@@ -585,6 +601,7 @@ unsafe fn atomic_load(src: *mut u128, order: Ordering) -> u128 {
             target_os = "freebsd",
             target_os = "netbsd",
             target_os = "openbsd",
+            target_os = "illumos",
             // These don't support detection of FEAT_LSE2.
             // target_os = "fuchsia",
             // target_os = "windows",
@@ -884,6 +901,7 @@ unsafe fn atomic_store(dst: *mut u128, val: u128, order: Ordering) {
             target_os = "freebsd",
             target_os = "netbsd",
             target_os = "openbsd",
+            target_os = "illumos",
             // These don't support detection of FEAT_LSE2.
             // target_os = "fuchsia",
             // target_os = "windows",
@@ -1004,6 +1022,7 @@ unsafe fn atomic_store(dst: *mut u128, val: u128, order: Ordering) {
             target_os = "freebsd",
             target_os = "netbsd",
             target_os = "openbsd",
+            target_os = "illumos",
             // These don't support detection of FEAT_LSE2.
             // target_os = "fuchsia",
             // target_os = "windows",
@@ -1218,6 +1237,7 @@ unsafe fn atomic_compare_exchange(
             target_os = "freebsd",
             target_os = "netbsd",
             target_os = "openbsd",
+            target_os = "illumos",
             target_os = "fuchsia",
             target_os = "windows",
         ),
@@ -1356,6 +1376,7 @@ unsafe fn atomic_compare_exchange(
             target_os = "freebsd",
             target_os = "netbsd",
             target_os = "openbsd",
+            target_os = "illumos",
             target_os = "fuchsia",
             target_os = "windows",
         ),

src/imp/atomic128/detect/aarch64_illumos.rs

@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+// Run-time CPU feature detection on AArch64 illumos by using getisax.
+
+include!("common.rs");
+
+// core::ffi::c_* (except c_void) requires Rust 1.64, libc will soon require Rust 1.47
+#[allow(non_camel_case_types)]
+mod ffi {
+    pub(crate) use super::c_types::c_uint;
+
+    // Defined in sys/auxv_aarch64.h.
+    // /~https://github.com/richlowe/illumos-gate/blob/arm64-gate/usr/src/uts/common/sys/auxv_aarch64.h
+    pub(crate) const AV_AARCH64_LSE: u32 = 1 << 15;
+    pub(crate) const AV_AARCH64_2_LSE2: u32 = 1 << 2;
+
+    extern "C" {
+        // Defined in sys/auxv.h.
+        // https://illumos.org/man/2/getisax
+        // /~https://github.com/richlowe/illumos-gate/blob/arm64-gate/usr/src/uts/common/sys/auxv.h
+        pub(crate) fn getisax(array: *mut u32, n: c_uint) -> c_uint;
+    }
+}
+
+#[cold]
+fn _detect(info: &mut CpuInfo) {
+    let mut out = [0_u32; 2];
+    // SAFETY: the pointer is valid because we got it from a reference.
+    unsafe {
+        ffi::getisax(out.as_mut_ptr(), 2);
+    }
+    if out[0] & ffi::AV_AARCH64_LSE != 0 {
+        info.set(CpuInfo::HAS_LSE);
+    }
+    if out[1] & ffi::AV_AARCH64_2_LSE2 != 0 {
+        info.set(CpuInfo::HAS_LSE2);
+    }
+}
+
+#[allow(
+    clippy::alloc_instead_of_core,
+    clippy::std_instead_of_alloc,
+    clippy::std_instead_of_core,
+    clippy::undocumented_unsafe_blocks,
+    clippy::wildcard_imports
+)]
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    // Static assertions for FFI bindings.
+    // This checks that FFI bindings defined in this crate and FFI bindings
+    // generated for the platform's latest header file using bindgen have
+    // compatible signatures (or the same values if constants).
+    // Since this is static assertion, we can detect problems with
+    // `cargo check --tests --target <target>` run in CI (via TESTS=1 build.sh)
+    // without actually running tests on these platforms.
+    // See also tools/codegen/src/ffi.rs.
+    // TODO(codegen): auto-generate this test
+    #[allow(
+        clippy::cast_possible_wrap,
+        clippy::cast_sign_loss,
+        clippy::cast_possible_truncation,
+        clippy::no_effect_underscore_binding
+    )]
+    const _: fn() = || {
+        use test_helper::sys;
+        let mut _getisax: unsafe extern "C" fn(*mut u32, ffi::c_uint) -> ffi::c_uint = ffi::getisax;
+        _getisax = sys::getisax;
+        static_assert!(ffi::AV_AARCH64_LSE == sys::AV_AARCH64_LSE);
+        static_assert!(ffi::AV_AARCH64_2_LSE2 == sys::AV_AARCH64_2_LSE2);
+    };
+}

tools/build.sh

@@ -70,6 +70,7 @@ default_targets=(
     aarch64-unknown-linux-uclibc # custom target
     aarch64-unknown-netbsd
     aarch64-unknown-openbsd
+    aarch64-unknown-illumos
     # aarch64 with FEAT_LSE & FEAT_LSE2
     aarch64-apple-darwin
     # aarch64 big endian