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std_detect: Use elf_aux_info on FreeBSD

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Taiki Endo 2024-09-15 20:10:08 +09:00 • committed by Amanieu d'Antras
parent 8a511191a0
commit 720973b1b4
2 changed files with 27 additions and 60 deletions
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80
library/stdarch/crates/std_detect/src/detect/os/freebsd/auxvec.rs
View file

@ -9,11 +9,6 @@
allow(dead_code)
)]
/// Key to access the CPU Hardware capabilities bitfield.
pub(crate) const AT_HWCAP: usize = 25;
/// Key to access the CPU Hardware capabilities 2 bitfield.
pub(crate) const AT_HWCAP2: usize = 26;
/// Cache HWCAP bitfields of the ELF Auxiliary Vector.
///
/// If an entry cannot be read all the bits in the bitfield are set to zero.
@ -38,65 +33,34 @@ pub(crate) struct AuxVec {
///
/// [elf_common.h]: https://svnweb.freebsd.org/base/release/12.0.0/sys/sys/elf_common.h?revision=341707
pub(crate) fn auxv() -> Result<AuxVec, ()> {
if let Ok(hwcap) = archauxv(AT_HWCAP) {
if let Ok(hwcap2) = archauxv(AT_HWCAP2) {
if hwcap != 0 && hwcap2 != 0 {
return Ok(AuxVec { hwcap, hwcap2 });
}
}
let hwcap = archauxv(libc::AT_HWCAP);
let hwcap2 = archauxv(libc::AT_HWCAP2);
// Zero could indicate that no features were detected, but it's also used to
// indicate an error. In particular, on many platforms AT_HWCAP2 will be
// legitimately zero, since it contains the most recent feature flags.
if hwcap != 0 || hwcap2 != 0 {
return Ok(AuxVec { hwcap, hwcap2 });
}
Err(())
}
/// Tries to read the `key` from the auxiliary vector.
fn archauxv(key: usize) -> Result<usize, ()> {
use core::mem;
#[derive(Copy, Clone)]
#[repr(C)]
pub struct Elf_Auxinfo {
pub a_type: usize,
pub a_un: unnamed,
}
#[derive(Copy, Clone)]
#[repr(C)]
pub union unnamed {
pub a_val: libc::c_long,
pub a_ptr: *mut libc::c_void,
pub a_fcn: Option<unsafe extern "C" fn() -> ()>,
}
let mut auxv: [Elf_Auxinfo; 27] = [Elf_Auxinfo {
a_type: 0,
a_un: unnamed { a_val: 0 },
}; 27];
let mut len: libc::c_uint = mem::size_of_val(&auxv) as libc::c_uint;
fn archauxv(key: libc::c_int) -> usize {
const OUT_LEN: libc::c_int = core::mem::size_of::<libc::c_ulong>() as libc::c_int;
let mut out: libc::c_ulong = 0;
unsafe {
let mut mib = [
libc::CTL_KERN,
libc::KERN_PROC,
libc::KERN_PROC_AUXV,
libc::getpid(),
];
let ret = libc::sysctl(
mib.as_mut_ptr(),
mib.len() as u32,
&mut auxv as *mut _ as *mut _,
&mut len as *mut _ as *mut _,
0 as *mut libc::c_void,
0,
// elf_aux_info is available on FreeBSD 12.0+ and 11.4+:
// https://github.com/freebsd/freebsd-src/commit/0b08ae2120cdd08c20a2b806e2fcef4d0a36c470
// https://github.com/freebsd/freebsd-src/blob/release/11.4.0/sys/sys/auxv.h
// FreeBSD 11 support in std has been removed in Rust 1.75 (https://github.com/rust-lang/rust/pull/114521),
// so we can safely use this function.
let res = libc::elf_aux_info(
key,
&mut out as *mut libc::c_ulong as *mut libc::c_void,
OUT_LEN,
);
if ret != -1 {
for i in 0..auxv.len() {
if auxv[i].a_type == key {
return Ok(auxv[i].a_un.a_val as usize);
}
}
}
// If elf_aux_info fails, `out` will be left at zero (which is the proper default value).
debug_assert!(res == 0 || out == 0);
}
return Ok(0);
out as usize
}

7
library/stdarch/crates/std_detect/tests/cpu-detection.rs
View file

@ -228,8 +228,11 @@ fn powerpc_linux() {
}
#[test]
#[cfg(all(target_arch = "powerpc64", target_os = "linux"))]
fn powerpc64_linux() {
#[cfg(all(
target_arch = "powerpc64",
any(target_os = "linux", target_os = "freebsd"),
))]
fn powerpc64_linux_or_freebsd() {
println!("altivec: {}", is_powerpc64_feature_detected!("altivec"));
println!("vsx: {}", is_powerpc64_feature_detected!("vsx"));
println!("power8: {}", is_powerpc64_feature_detected!("power8"));