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MSRV 1.60: cpu: Use std::arch::is_aarch64_feature_detected on AArch64. #1542

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MSRV 1.60: cpu: Use std::arch::is_aarch64_feature_detected on AArch64. #1542

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8ace2b1
Use `cfg!(target_feature)` for static AARCH64 feature detection.
briansmith Oct 29, 2022
3ea090f
cpu: Clarify Windows static feature detection.
briansmith Oct 29, 2022
cff897e
cpu: Use `std::arch::is_aarch64_feature_detected` on AArch64.
briansmith Oct 28, 2022
07b68f3
cpu: Expand dynamic detection to all supported OSs on AArch64.
briansmith Oct 30, 2022
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7 changes: 2 additions & 5 deletions Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -167,15 +167,12 @@ name = "ring"
getrandom = { version = "0.2.8" }
untrusted = { version = "0.9" }

[target.'cfg(any(target_arch = "x86",target_arch = "x86_64", all(any(target_arch = "aarch64", target_arch = "arm"), any(target_os = "android", target_os = "fuchsia", target_os = "linux", target_os = "windows"))))'.dependencies]
[target.'cfg(any(target_arch = "x86",target_arch = "x86_64", all(target_arch = "aarch64", any(target_family = "unix", target_family = "windows")), all(target_arch = "arm", any(target_os = "android", target_os = "fuchsia", target_os = "linux", target_os = "windows"))))'.dependencies]
spin = { version = "0.9.2", default-features = false, features = ["once"] }

[target.'cfg(any(target_os = "android", target_os = "linux"))'.dependencies]
[target.'cfg(all(target_arch = "arm", any(target_os = "android", target_os = "linux")))'.dependencies]
libc = { version = "0.2.100", default-features = false }

[target.'cfg(all(target_arch = "aarch64", target_os = "windows"))'.dependencies]
windows-sys = { version = "0.48", features = ["Win32_Foundation", "Win32_System_Threading"] }

[target.'cfg(target_arch = "wasm32")'.dev-dependencies]
wasm-bindgen-test = { version = "0.3.26", default-features = false }

Expand Down
33 changes: 21 additions & 12 deletions src/cpu.rs
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Expand Up @@ -24,13 +24,30 @@ pub(crate) struct Features(());

#[inline(always)]
pub(crate) fn features() -> Features {
// We don't do runtime feature detection on aarch64-apple-* as all AAarch64
// features we use are available on every device since the first devices.
// TODO: The list of operating systems for `aarch64` should really be
// "whatever has `std::arch::is_aarch64_feature_detected`".
#[cfg(any(
target_arch = "x86",
target_arch = "x86_64",
all(
any(target_arch = "aarch64", target_arch = "arm"),
target_arch = "aarch64",
any(
target_os = "android",
target_os = "dragonfly",
target_os = "freebsd",
target_os = "illumos",
target_os = "ios",
target_os = "linux",
target_os = "macos",
target_os = "netbsd",
target_os = "openbsd",
target_os = "redox",
target_os = "solaris",
target_os = "windows",
)
),
all(
target_arch = "arm",
any(
target_os = "android",
target_os = "fuchsia",
Expand All @@ -52,15 +69,7 @@ pub(crate) fn features() -> Features {
}
}

#[cfg(all(
any(target_arch = "aarch64", target_arch = "arm"),
any(
target_os = "android",
target_os = "fuchsia",
target_os = "linux",
target_os = "windows"
)
))]
#[cfg(any(target_arch = "aarch64", target_arch = "arm"))]
{
arm::setup();
}
Expand Down
176 changes: 38 additions & 138 deletions src/cpu/arm.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -12,142 +12,50 @@
// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

#[cfg(all(
any(target_os = "android", target_os = "linux"),
any(target_arch = "aarch64", target_arch = "arm")
))]
// TODO(MSRV): Replace this with use of `std::arch::is_arm_feature_detected!()`.
#[cfg(all(target_arch = "arm", any(target_os = "android", target_os = "linux")))]
pub fn setup() {
use libc::c_ulong;
use libc::{c_ulong, getauxval, AT_HWCAP};

// XXX: The `libc` crate doesn't provide `libc::getauxval` consistently
// across all Android/Linux targets, e.g. musl.
extern "C" {
fn getauxval(type_: c_ulong) -> c_ulong;
}

const AT_HWCAP: c_ulong = 16;

#[cfg(target_arch = "aarch64")]
const HWCAP_NEON: c_ulong = 1 << 1;

#[cfg(target_arch = "arm")]
const HWCAP_NEON: c_ulong = 1 << 12;

let caps = unsafe { getauxval(AT_HWCAP) };

// We assume NEON is available on AARCH64 because it is a required
// feature.
#[cfg(target_arch = "aarch64")]
debug_assert!(caps & HWCAP_NEON == HWCAP_NEON);

// OpenSSL and BoringSSL don't enable any other features if NEON isn't
// available.
if caps & HWCAP_NEON == HWCAP_NEON {
let mut features = NEON.mask;

#[cfg(target_arch = "aarch64")]
const OFFSET: c_ulong = 3;

#[cfg(target_arch = "arm")]
const OFFSET: c_ulong = 0;

#[cfg(target_arch = "arm")]
let caps = {
const AT_HWCAP2: c_ulong = 26;
unsafe { getauxval(AT_HWCAP2) }
};

const HWCAP_AES: c_ulong = 1 << 0 + OFFSET;
const HWCAP_PMULL: c_ulong = 1 << 1 + OFFSET;
const HWCAP_SHA2: c_ulong = 1 << 3 + OFFSET;
const HWCAP2_AES: c_ulong = 1 << 0;
const HWCAP2_PMULL: c_ulong = 1 << 1;
const HWCAP2_SHA2: c_ulong = 1 << 3;

if caps & HWCAP_AES == HWCAP_AES {
if caps & HWCAP2_AES == HWCAP2_AES {
features |= AES.mask;
}
if caps & HWCAP_PMULL == HWCAP_PMULL {
if caps & HWCAP2_PMULL == HWCAP2_PMULL {
features |= PMULL.mask;
}
if caps & HWCAP_SHA2 == HWCAP_SHA2 {
if caps & HWCAP2_SHA2 == HWCAP2_SHA2 {
features |= SHA256.mask;
}

unsafe { OPENSSL_armcap_P = features };
}
}

#[cfg(all(target_os = "fuchsia", target_arch = "aarch64"))]
pub fn setup() {
type zx_status_t = i32;

#[link(name = "zircon")]
extern "C" {
fn zx_system_get_features(kind: u32, features: *mut u32) -> zx_status_t;
}

const ZX_OK: i32 = 0;
const ZX_FEATURE_KIND_CPU: u32 = 0;
const ZX_ARM64_FEATURE_ISA_ASIMD: u32 = 1 << 2;
const ZX_ARM64_FEATURE_ISA_AES: u32 = 1 << 3;
const ZX_ARM64_FEATURE_ISA_PMULL: u32 = 1 << 4;
const ZX_ARM64_FEATURE_ISA_SHA2: u32 = 1 << 6;

let mut caps = 0;
let rc = unsafe { zx_system_get_features(ZX_FEATURE_KIND_CPU, &mut caps) };

// OpenSSL and BoringSSL don't enable any other features if NEON isn't
// available.
if rc == ZX_OK && (caps & ZX_ARM64_FEATURE_ISA_ASIMD == ZX_ARM64_FEATURE_ISA_ASIMD) {
let mut features = NEON.mask;

if caps & ZX_ARM64_FEATURE_ISA_AES == ZX_ARM64_FEATURE_ISA_AES {
features |= AES.mask;
}
if caps & ZX_ARM64_FEATURE_ISA_PMULL == ZX_ARM64_FEATURE_ISA_PMULL {
features |= PMULL.mask;
}
if caps & ZX_ARM64_FEATURE_ISA_SHA2 == ZX_ARM64_FEATURE_ISA_SHA2 {
features |= 1 << 4;
}

unsafe { OPENSSL_armcap_P = features };
}
}

#[cfg(all(target_os = "windows", target_arch = "aarch64"))]
pub fn setup() {
// We do not need to check for the presence of NEON, as Armv8-A always has it
let mut features = NEON.mask;

let result = unsafe {
windows_sys::Win32::System::Threading::IsProcessorFeaturePresent(
windows_sys::Win32::System::Threading::PF_ARM_V8_CRYPTO_INSTRUCTIONS_AVAILABLE,
)
};

if result != 0 {
// These are all covered by one call in Windows
features |= AES.mask;
features |= PMULL.mask;
features |= SHA256.mask;
}

unsafe { OPENSSL_armcap_P = features };
}

macro_rules! features {
{
{ // Use `:tt` instead of `:literal` to work around
// https://github.com/rust-lang/rust/issues/72726.
$(
$name:ident {
$static_target_feature_name:literal then $dynamic_target_feature_name:tt => $name:ident {
mask: $mask:expr,

// Should we assume that the feature is always available
// for aarch64-apple-* targets? The first AArch64 iOS
// device used the Apple A7 chip.
// TODO: When we can use `if` in const expressions:
// ```
// aarch64_apple: $aarch64_apple,
// ```
aarch64_apple: true,
}
),+
, // trailing comma is required.
Expand All @@ -159,30 +67,23 @@ macro_rules! features {
};
)+

// TODO: When we can use `if` in const expressions, do this:
// ```
// const ARMCAP_STATIC: u32 = 0
// $(
// | ( if $aarch64_apple &&
// cfg!(all(target_arch = "aarch64",
// target_vendor = "apple")) {
// $name.mask
// } else {
// 0
// }
// )
// )+;
// ```
//
// TODO: Add static feature detection to other targets.
// TODO: Combine static feature detection with runtime feature
// detection.
#[cfg(all(target_arch = "aarch64", target_vendor = "apple"))]
#[cfg(all(target_arch = "aarch64", any(target_family = "unix", target_family = "windows")))]
pub fn setup() {
extern crate std;
use std::arch::is_aarch64_feature_detected;

let features = 0
$(
| (if is_aarch64_feature_detected!($dynamic_target_feature_name) { $name.mask } else { 0 })
)+;
debug_assert_eq!(features & ARMCAP_STATIC, ARMCAP_STATIC);
unsafe { OPENSSL_armcap_P = features };
}

const ARMCAP_STATIC: u32 = 0
$( | $name.mask
$(
| ( if cfg!(target_feature = $static_target_feature_name) { $name.mask } else { 0 } )
)+;
#[cfg(not(all(target_arch = "aarch64", target_vendor = "apple")))]
const ARMCAP_STATIC: u32 = 0;

const _ALL_FEATURES_MASK: u32 = 0
$( | $name.mask
Expand Down Expand Up @@ -227,29 +128,28 @@ impl Feature {
}
}

// Assumes all target feature names are the same for ARM and AAarch64.
features! {
// Keep in sync with `ARMV7_NEON`.
NEON {
"neon" then "neon" => NEON {
mask: 1 << 0,
aarch64_apple: true,
},

// Keep in sync with `ARMV8_AES`.
AES {
"aes" then "aes" => AES {
mask: 1 << 2,
aarch64_apple: true,
},

// Keep in sync with `ARMV8_SHA256`.
SHA256 {
"sha2" then "sha2" => SHA256 {
mask: 1 << 4,
aarch64_apple: true,
},

// Keep in sync with `ARMV8_PMULL`.
PMULL {
// TODO(MSRV): There is no "pmull" feature listed from
// `rustc --print cfg --target=aarch64-apple-darwin`. Originally ARMv8 tied
// PMULL detection into AES detection, but later versions split it; see
// https://developer.arm.com/downloads/-/exploration-tools/feature-names-for-a-profile
// "Features introduced prior to 2020." Change this to use "pmull" when
// that is supported.
"aes" then "pmull" => PMULL {
mask: 1 << 5,
aarch64_apple: true,
},
}

Expand Down
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