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cpufeatures: aarch64 support (Linux and macOS/M4)
Adds preliminary support for runtime feature detection on `aarch64` targets, presently restricted to the following set of target features which are present on both `aarch64-unknown-linux-gnu` and `aarch64-apple-darwin` targets: - `aes`: AES support - `sha2`: SHA1 and SHA256 support - `sha3`: SHA512 and SHA3 support
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[package] | ||
name = "cpufeatures" | ||
version = "0.1.0" # Also update html_root_url in lib.rs when bumping this | ||
description = """ | ||
Lightweight and efficient no-std compatible alternative to the | ||
is_x86_feature_detected! macro | ||
""" | ||
authors = ["RustCrypto Developers"] | ||
license = "MIT OR Apache-2.0" | ||
description = "Lightweight and efficient no-std compatible alternative to the is_x86_feature_detected macro" | ||
documentation = "https://docs.rs/cpufeatures" | ||
repository = "https://github.com/RustCrypto/utils" | ||
keywords = ["cpuid", "target-feature"] | ||
categories = ["no-std"] | ||
edition = "2018" | ||
readme = "README.md" | ||
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[target.aarch64-apple-darwin.dependencies] | ||
libc = "0.2" | ||
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[target.'cfg(all(target_arch = "aarch64", target_os = "linux"))'.dependencies] | ||
libc = "0.2" |
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//! ARM64 CPU feature detection support. | ||
//! | ||
//! Unfortunately ARM instructions to detect CPU features cannot be called from | ||
//! unprivileged userspace code, so this implementation relies on OS-specific | ||
//! APIs for feature detection. | ||
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#[macro_export] | ||
#[doc(hidden)] | ||
macro_rules! __unless_target_features { | ||
($($tf:tt),+ => $body:expr ) => { | ||
{ | ||
#[cfg(not(all($(target_feature=$tf,)*)))] | ||
$body | ||
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#[cfg(all($(target_feature=$tf,)*))] | ||
true | ||
} | ||
}; | ||
} | ||
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#[cfg(target_os = "linux")] | ||
#[macro_export] | ||
#[doc(hidden)] | ||
macro_rules! __detect_target_features { | ||
($($tf:tt),+) => {{ | ||
let hwcaps = unsafe { libc::getauxval(libc::AT_HWCAP) }; | ||
$($crate::check!(hwcaps, $tf) & )+ true | ||
}}; | ||
} | ||
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#[cfg(target_os = "macos")] | ||
#[macro_export] | ||
#[doc(hidden)] | ||
macro_rules! __detect_target_features { | ||
($($tf:tt),+) => {{ | ||
$($crate::check!($tf) & )+ true | ||
}}; | ||
} | ||
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/// Linux `expand_check_macro` | ||
#[cfg(target_os = "linux")] | ||
macro_rules! __expand_check_macro { | ||
($(($name:tt, $hwcap:expr)),* $(,)?) => { | ||
#[macro_export] | ||
#[doc(hidden)] | ||
macro_rules! check { | ||
$( | ||
($hwcaps:expr, $name) => { (($hwcaps & libc::$hwcap) != 0) }; | ||
)* | ||
} | ||
}; | ||
} | ||
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/// Linux `expand_check_macro` | ||
#[cfg(target_os = "linux")] | ||
__expand_check_macro! { | ||
("aes", HWCAP_AES), // Enable AES support. | ||
("sha2", HWCAP_SHA2), // Enable SHA1 and SHA256 support. | ||
("sha3", HWCAP_SHA3), // Enable SHA512 and SHA3 support. | ||
} | ||
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/// macOS `check!` macro. | ||
/// | ||
/// NOTE: several of these instructions (e.g. `aes`, `sha2`) can be assumed to | ||
/// be present on all Apple ARM64 hardware. | ||
/// | ||
/// Newer CPU instructions now have nodes within sysctl's `hw.optional` | ||
/// namespace, however the ones that do not can safely be assumed to be | ||
/// present on all Apple ARM64 devices, now and for the foreseeable future. | ||
/// | ||
/// See discussion on this issue for more information: | ||
/// <https://github.com/RustCrypto/utils/issues/378> | ||
#[cfg(target_os = "macos")] | ||
#[macro_export] | ||
#[doc(hidden)] | ||
macro_rules! check { | ||
("aes") => { | ||
true | ||
}; | ||
("sha2") => { | ||
true | ||
}; | ||
("sha3") => { | ||
unsafe { $crate::aarch64::sysctlbyname(b"hw.optional.armv8_2_sha3\0") } | ||
}; | ||
} | ||
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/// macOS helper function for calling `sysctlbyname`. | ||
#[cfg(target_os = "macos")] | ||
pub unsafe fn sysctlbyname(name: &[u8]) -> bool { | ||
assert_eq!( | ||
name.last().cloned(), | ||
Some(0), | ||
"name is not NUL terminated: {:?}", | ||
name | ||
); | ||
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let mut value: u32 = 0; | ||
let mut size = core::mem::size_of::<u32>(); | ||
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let rc = libc::sysctlbyname( | ||
name.as_ptr() as *const i8, | ||
&mut value as *mut _ as *mut libc::c_void, | ||
&mut size, | ||
core::ptr::null_mut(), | ||
0, | ||
); | ||
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assert_eq!(size, 4, "unexpected sysctlbyname(3) result size"); | ||
assert_eq!(rc, 0, "sysctlbyname returned error code: {}", rc); | ||
value != 0 | ||
} |
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