diff options
Diffstat (limited to 'vendor/portable-atomic/src/imp/atomic128/detect/auxv.rs')
| -rw-r--r-- | vendor/portable-atomic/src/imp/atomic128/detect/auxv.rs | 727 |
1 files changed, 727 insertions, 0 deletions
diff --git a/vendor/portable-atomic/src/imp/atomic128/detect/auxv.rs b/vendor/portable-atomic/src/imp/atomic128/detect/auxv.rs new file mode 100644 index 0000000..1be3095 --- /dev/null +++ b/vendor/portable-atomic/src/imp/atomic128/detect/auxv.rs @@ -0,0 +1,727 @@ +// SPDX-License-Identifier: Apache-2.0 OR MIT + +// Run-time feature detection on aarch64/powerpc64 Linux/Android/FreeBSD by parsing ELF auxiliary vectors. +// +// # Linux/Android +// +// As of nightly-2023-01-23, is_aarch64_feature_detected always uses dlsym by default +// on aarch64 Linux/Android, but on the following platforms, so we can safely assume +// getauxval is linked to the binary. +// +// - On glibc (*-linux-gnu*), [aarch64 support is available on glibc 2.17+](https://sourceware.org/legacy-ml/libc-announce/2012/msg00001.html) +// and is newer than [glibc 2.16 that added getauxval](https://sourceware.org/legacy-ml/libc-announce/2012/msg00000.html). +// - On musl (*-linux-musl*, *-linux-ohos*), [aarch64 support is available on musl 1.1.7+](https://git.musl-libc.org/cgit/musl/tree/WHATSNEW?h=v1.1.7#n1422) +// and is newer than [musl 1.1.0 that added getauxval](https://git.musl-libc.org/cgit/musl/tree/WHATSNEW?h=v1.1.0#n1197). +// https://github.com/rust-lang/rust/commit/9a04ae4997493e9260352064163285cddc43de3c +// - On bionic (*-android*), [64-bit architecture support is available on Android 5.0+ (API level 21+)](https://android-developers.googleblog.com/2014/10/whats-new-in-android-50-lollipop.html) +// and is newer than [Android 4.3 (API level 18) that added getauxval](https://github.com/aosp-mirror/platform_bionic/blob/d3ebc2f7c49a9893b114124d4a6b315f3a328764/libc/include/sys/auxv.h#L49). +// +// However, on musl with static linking, it seems that getauxval is not always available, independent of version requirements: https://github.com/rust-lang/rust/issues/89626 +// (That problem may have been fixed in https://github.com/rust-lang/rust/commit/9a04ae4997493e9260352064163285cddc43de3c, +// but even in the version containing that patch, [there is report](https://github.com/rust-lang/rust/issues/89626#issuecomment-1242636038) +// of the same error.) +// +// On other Linux targets, we cannot assume that getauxval is always available, so we don't enable +// outline-atomics by default (can be enabled by `--cfg portable_atomic_outline_atomics`). +// +// - On musl with static linking. See the above for more. +// Also, in this case, dlsym(getauxval) always returns null. +// - On uClibc-ng (*-linux-uclibc*, *-l4re-uclibc*), [uClibc-ng 1.0.43 (released in 2023-04-05) added getauxval](https://github.com/wbx-github/uclibc-ng/commit/d869bb1600942c01a77539128f9ba5b5b55ad647). +// - On Picolibc, [Picolibc 1.4.6 added getauxval stub](https://github.com/picolibc/picolibc#picolibc-version-146). +// +// See also https://github.com/rust-lang/stdarch/pull/1375 +// +// See tests::test_linux_like and aarch64_aa64reg.rs for (test-only) alternative implementations. +// +// # FreeBSD +// +// As of nightly-2023-01-23, is_aarch64_feature_detected always uses mrs on +// aarch64 FreeBSD. However, they do not work on FreeBSD 12 on QEMU (confirmed +// on FreeBSD 12.{2,3,4}), and we got SIGILL (worked on FreeBSD 13 and 14). +// +// So use elf_aux_info instead of mrs like compiler-rt does. +// https://man.freebsd.org/elf_aux_info(3) +// https://reviews.llvm.org/D109330 +// +// 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 +// On FreeBSD, [aarch64 support is available on FreeBSD 11.0+](https://www.freebsd.org/releases/11.0R/relnotes/#hardware-arm), +// but FreeBSD 11 (11.4) was EoL on 2021-09-30, and FreeBSD 11.3 was EoL on 2020-09-30: +// https://www.freebsd.org/security/unsupported +// See also https://github.com/rust-lang/stdarch/pull/611#issuecomment-445464613 +// +// See tests::test_freebsd and aarch64_aa64reg.rs for (test-only) alternative implementations. +// +// # PowerPC64 +// +// On PowerPC64, outline-atomics is currently disabled by default mainly for +// compatibility with older versions of operating systems +// (can be enabled by `--cfg portable_atomic_outline_atomics`). + +include!("common.rs"); + +use os::ffi; +#[cfg(any(target_os = "linux", target_os = "android"))] +mod os { + // core::ffi::c_* (except c_void) requires Rust 1.64, libc will soon require Rust 1.47 + #[cfg_attr(test, allow(dead_code))] + pub(super) mod ffi { + pub(crate) use super::super::c_types::c_ulong; + #[cfg(all(target_arch = "aarch64", target_os = "android"))] + pub(crate) use super::super::c_types::{c_char, c_int}; + + extern "C" { + // https://man7.org/linux/man-pages/man3/getauxval.3.html + // https://github.com/bminor/glibc/blob/801af9fafd4689337ebf27260aa115335a0cb2bc/misc/sys/auxv.h + // https://github.com/bminor/musl/blob/7d756e1c04de6eb3f2b3d3e1141a218bb329fcfb/include/sys/auxv.h + // https://github.com/wbx-github/uclibc-ng/blob/cdb07d2cd52af39feb425e6d36c02b30916b9f0a/include/sys/auxv.h + // https://github.com/aosp-mirror/platform_bionic/blob/d3ebc2f7c49a9893b114124d4a6b315f3a328764/libc/include/sys/auxv.h + // https://github.com/picolibc/picolibc/blob/7a8a58aeaa5946cb662577a518051091b691af3a/newlib/libc/picolib/getauxval.c + // https://github.com/rust-lang/libc/blob/0.2.139/src/unix/linux_like/linux/gnu/mod.rs#L1201 + // https://github.com/rust-lang/libc/blob/0.2.139/src/unix/linux_like/linux/musl/mod.rs#L744 + // https://github.com/rust-lang/libc/blob/0.2.139/src/unix/linux_like/android/b64/mod.rs#L333 + pub(crate) fn getauxval(type_: c_ulong) -> c_ulong; + + // Defined in sys/system_properties.h. + // https://github.com/aosp-mirror/platform_bionic/blob/d3ebc2f7c49a9893b114124d4a6b315f3a328764/libc/include/sys/system_properties.h + // https://github.com/rust-lang/libc/blob/0.2.139/src/unix/linux_like/android/mod.rs#L3471 + #[cfg(all(target_arch = "aarch64", target_os = "android"))] + pub(crate) fn __system_property_get(name: *const c_char, value: *mut c_char) -> c_int; + } + + // https://github.com/torvalds/linux/blob/v6.1/include/uapi/linux/auxvec.h + #[cfg(any(test, target_arch = "aarch64"))] + pub(crate) const AT_HWCAP: c_ulong = 16; + #[cfg(any(test, target_arch = "powerpc64"))] + pub(crate) const AT_HWCAP2: c_ulong = 26; + + // Defined in sys/system_properties.h. + // https://github.com/aosp-mirror/platform_bionic/blob/d3ebc2f7c49a9893b114124d4a6b315f3a328764/libc/include/sys/system_properties.h + #[cfg(all(target_arch = "aarch64", target_os = "android"))] + pub(crate) const PROP_VALUE_MAX: c_int = 92; + } + + pub(super) fn getauxval(type_: ffi::c_ulong) -> ffi::c_ulong { + #[cfg(all(target_arch = "aarch64", target_os = "android"))] + { + // Samsung Exynos 9810 has a bug that big and little cores have different + // ISAs. And on older Android (pre-9), the kernel incorrectly reports + // that features available only on some cores are available on all cores. + // https://reviews.llvm.org/D114523 + let mut arch = [0_u8; ffi::PROP_VALUE_MAX as usize]; + // SAFETY: we've passed a valid C string and a buffer with max length. + let len = unsafe { + ffi::__system_property_get( + b"ro.arch\0".as_ptr().cast::<ffi::c_char>(), + arch.as_mut_ptr().cast::<ffi::c_char>(), + ) + }; + // On Exynos, ro.arch is not available on Android 12+, but it is fine + // because Android 9+ includes the fix. + if len > 0 && arch.starts_with(b"exynos9810") { + return 0; + } + } + + // SAFETY: `getauxval` is thread-safe. See also the module level docs. + unsafe { ffi::getauxval(type_) } + } +} +#[cfg(target_os = "freebsd")] +mod os { + // core::ffi::c_* (except c_void) requires Rust 1.64, libc will soon require Rust 1.47 + #[cfg_attr(test, allow(dead_code))] + pub(super) mod ffi { + pub(crate) use super::super::c_types::{c_int, c_ulong, c_void}; + + extern "C" { + // Defined in sys/auxv.h. + // https://man.freebsd.org/elf_aux_info(3) + // https://github.com/freebsd/freebsd-src/blob/deb63adf945d446ed91a9d84124c71f15ae571d1/sys/sys/auxv.h + pub(crate) fn elf_aux_info(aux: c_int, buf: *mut c_void, buf_len: c_int) -> c_int; + } + + // Defined in sys/elf_common.h. + // https://github.com/freebsd/freebsd-src/blob/deb63adf945d446ed91a9d84124c71f15ae571d1/sys/sys/elf_common.h + #[cfg(any(test, target_arch = "aarch64"))] + pub(crate) const AT_HWCAP: c_int = 25; + #[cfg(any(test, target_arch = "powerpc64"))] + pub(crate) const AT_HWCAP2: c_int = 26; + } + + pub(super) fn getauxval(aux: ffi::c_int) -> ffi::c_ulong { + #[allow(clippy::cast_possible_wrap, clippy::cast_possible_truncation)] + const OUT_LEN: ffi::c_int = core::mem::size_of::<ffi::c_ulong>() as ffi::c_int; + let mut out: ffi::c_ulong = 0; + // SAFETY: + // - the pointer is valid because we got it from a reference. + // - `OUT_LEN` is the same as the size of `out`. + // - `elf_aux_info` is thread-safe. + unsafe { + let res = ffi::elf_aux_info( + aux, + (&mut out as *mut ffi::c_ulong).cast::<ffi::c_void>(), + OUT_LEN, + ); + // If elf_aux_info fails, `out` will be left at zero (which is the proper default value). + debug_assert!(res == 0 || out == 0); + } + out + } +} + +// Basically, Linux and FreeBSD use the same hwcap values. +// FreeBSD supports a subset of the hwcap values supported by Linux. +use arch::_detect; +#[cfg(target_arch = "aarch64")] +mod arch { + use super::{ffi, os, CpuInfo}; + + // Linux + // https://github.com/torvalds/linux/blob/1c41041124bd14dd6610da256a3da4e5b74ce6b1/arch/arm64/include/uapi/asm/hwcap.h + // FreeBSD + // Defined in machine/elf.h. + // https://github.com/freebsd/freebsd-src/blob/deb63adf945d446ed91a9d84124c71f15ae571d1/sys/arm64/include/elf.h + // available on FreeBSD 13.0+ and 12.2+ + // https://github.com/freebsd/freebsd-src/blob/release/13.0.0/sys/arm64/include/elf.h + // https://github.com/freebsd/freebsd-src/blob/release/12.2.0/sys/arm64/include/elf.h + pub(super) const HWCAP_ATOMICS: ffi::c_ulong = 1 << 8; + pub(super) const HWCAP_USCAT: ffi::c_ulong = 1 << 25; + #[cfg(any(target_os = "linux", target_os = "android"))] + #[cfg(target_pointer_width = "64")] + #[cfg(test)] + pub(super) const HWCAP2_LRCPC3: ffi::c_ulong = 1 << 46; + #[cfg(any(target_os = "linux", target_os = "android"))] + #[cfg(target_pointer_width = "64")] + #[cfg(test)] + pub(super) const HWCAP2_LSE128: ffi::c_ulong = 1 << 47; + + #[cold] + pub(super) fn _detect(info: &mut CpuInfo) { + let hwcap = os::getauxval(ffi::AT_HWCAP); + + if hwcap & HWCAP_ATOMICS != 0 { + info.set(CpuInfo::HAS_LSE); + } + if hwcap & HWCAP_USCAT != 0 { + info.set(CpuInfo::HAS_LSE2); + } + #[cfg(any(target_os = "linux", target_os = "android"))] + #[cfg(target_pointer_width = "64")] + #[cfg(test)] + { + let hwcap2 = os::getauxval(ffi::AT_HWCAP2); + if hwcap2 & HWCAP2_LRCPC3 != 0 { + info.set(CpuInfo::HAS_RCPC3); + } + if hwcap2 & HWCAP2_LSE128 != 0 { + info.set(CpuInfo::HAS_LSE128); + } + } + } +} +#[cfg(target_arch = "powerpc64")] +mod arch { + use super::{ffi, os, CpuInfo}; + + // Linux + // https://github.com/torvalds/linux/blob/v6.1/arch/powerpc/include/uapi/asm/cputable.h + // FreeBSD + // Defined in machine/cpu.h. + // https://github.com/freebsd/freebsd-src/blob/deb63adf945d446ed91a9d84124c71f15ae571d1/sys/powerpc/include/cpu.h + // available on FreeBSD 11.0+ + // https://github.com/freebsd/freebsd-src/commit/b0bf7fcd298133457991b27625bbed766e612730 + pub(super) const PPC_FEATURE2_ARCH_2_07: ffi::c_ulong = 0x80000000; + + #[cold] + pub(super) fn _detect(info: &mut CpuInfo) { + let hwcap2 = os::getauxval(ffi::AT_HWCAP2); + + // power8 + if hwcap2 & PPC_FEATURE2_ARCH_2_07 != 0 { + info.set(CpuInfo::HAS_QUADWORD_ATOMICS); + } + } +} + +#[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::*; + + #[cfg(any(target_os = "linux", target_os = "android"))] + #[cfg(target_pointer_width = "64")] + #[test] + fn test_linux_like() { + use c_types::*; + use core::{arch::asm, mem}; + use std::vec; + use test_helper::{libc, sys}; + + // Linux kernel 6.4 has added a way to read auxv without depending on either libc or mrs trap. + // https://github.com/torvalds/linux/commit/ddc65971bb677aa9f6a4c21f76d3133e106f88eb + // + // This is currently used only for testing. + fn getauxval_pr_get_auxv(type_: ffi::c_ulong) -> Result<ffi::c_ulong, c_int> { + #[cfg(target_arch = "aarch64")] + unsafe fn prctl_get_auxv(out: *mut c_void, len: usize) -> Result<usize, c_int> { + let r: i64; + unsafe { + asm!( + "svc 0", + in("x8") sys::__NR_prctl as u64, + inout("x0") sys::PR_GET_AUXV as u64 => r, + in("x1") ptr_reg!(out), + in("x2") len as u64, + // arg4 and arg5 must be zero. + in("x3") 0_u64, + in("x4") 0_u64, + options(nostack, preserves_flags) + ); + } + #[allow(clippy::cast_possible_truncation, clippy::cast_sign_loss)] + if (r as c_int) < 0 { + Err(r as c_int) + } else { + Ok(r as usize) + } + } + #[cfg(target_arch = "powerpc64")] + unsafe fn prctl_get_auxv(out: *mut c_void, len: usize) -> Result<usize, c_int> { + let r: i64; + unsafe { + asm!( + "sc", + "bns+ 2f", + "neg %r3, %r3", + "2:", + inout("r0") sys::__NR_prctl as u64 => _, + inout("r3") sys::PR_GET_AUXV as u64 => r, + inout("r4") ptr_reg!(out) => _, + inout("r5") len as u64 => _, + // arg4 and arg5 must be zero. + inout("r6") 0_u64 => _, + inout("r7") 0_u64 => _, + out("r8") _, + out("r9") _, + out("r10") _, + out("r11") _, + out("r12") _, + out("cr0") _, + options(nostack, preserves_flags) + ); + } + #[allow(clippy::cast_possible_truncation, clippy::cast_sign_loss)] + if (r as c_int) < 0 { + Err(r as c_int) + } else { + Ok(r as usize) + } + } + + let mut auxv = vec![unsafe { mem::zeroed::<sys::Elf64_auxv_t>() }; 38]; + + let old_len = auxv.len() * mem::size_of::<sys::Elf64_auxv_t>(); + + // SAFETY: + // - `out_len` does not exceed the size of `auxv`. + let _len = unsafe { prctl_get_auxv(auxv.as_mut_ptr().cast::<c_void>(), old_len)? }; + + for aux in &auxv { + if aux.a_type == type_ { + // SAFETY: aux.a_un is #[repr(C)] union and all fields have + // the same size and can be safely transmuted to integers. + return Ok(unsafe { aux.a_un.a_val }); + } + } + Err(0) + } + + unsafe { + let mut u = mem::zeroed(); + assert_eq!(libc::uname(&mut u), 0); + let release = std::ffi::CStr::from_ptr(u.release.as_ptr()); + let release = core::str::from_utf8(release.to_bytes()).unwrap(); + let mut digits = release.split('.'); + let major = digits.next().unwrap().parse::<u32>().unwrap(); + let minor = digits.next().unwrap().parse::<u32>().unwrap(); + if (major, minor) < (6, 4) { + std::eprintln!("kernel version: {major}.{minor} (no pr_get_auxv)"); + assert_eq!(getauxval_pr_get_auxv(ffi::AT_HWCAP).unwrap_err(), -22); + assert_eq!(getauxval_pr_get_auxv(ffi::AT_HWCAP2).unwrap_err(), -22); + } else { + std::eprintln!("kernel version: {major}.{minor} (has pr_get_auxv)"); + assert_eq!( + os::getauxval(ffi::AT_HWCAP), + getauxval_pr_get_auxv(ffi::AT_HWCAP).unwrap() + ); + assert_eq!( + os::getauxval(ffi::AT_HWCAP2), + getauxval_pr_get_auxv(ffi::AT_HWCAP2).unwrap() + ); + } + } + } + + #[allow(clippy::cast_sign_loss)] + #[cfg(all(target_arch = "aarch64", target_os = "android"))] + #[test] + fn test_android() { + unsafe { + let mut arch = [1; ffi::PROP_VALUE_MAX as usize]; + let len = ffi::__system_property_get( + b"ro.arch\0".as_ptr().cast::<ffi::c_char>(), + arch.as_mut_ptr().cast::<ffi::c_char>(), + ); + assert!(len >= 0); + std::eprintln!("len={}", len); + std::eprintln!("arch={:?}", arch); + std::eprintln!( + "arch={:?}", + core::str::from_utf8(core::slice::from_raw_parts(arch.as_ptr(), len as usize)) + .unwrap() + ); + } + } + + #[allow(clippy::cast_possible_wrap)] + #[cfg(target_os = "freebsd")] + #[test] + fn test_freebsd() { + use c_types::*; + use core::{arch::asm, mem, ptr}; + use test_helper::sys; + + // This is almost equivalent to what elf_aux_info does. + // https://man.freebsd.org/elf_aux_info(3) + // On FreeBSD, [aarch64 support is available on FreeBSD 11.0+](https://www.freebsd.org/releases/11.0R/relnotes/#hardware-arm), + // but 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 + // so use sysctl instead of elf_aux_info. + // Note that FreeBSD 11 (11.4) was EoL on 2021-09-30, and FreeBSD 11.3 was EoL on 2020-09-30: + // https://www.freebsd.org/security/unsupported + // + // std_detect uses this way, but it appears to be somewhat incorrect + // (the type of arg4 of sysctl, auxv is smaller than AT_COUNT, etc.). + // https://github.com/rust-lang/stdarch/blob/a0c30f3e3c75adcd6ee7efc94014ebcead61c507/crates/std_detect/src/detect/os/freebsd/auxvec.rs#L52 + // + // This is currently used only for testing. + // If you want us to use this implementation for compatibility with the older FreeBSD + // version that came to EoL a few years ago, please open an issue. + fn getauxval_sysctl_libc(type_: ffi::c_int) -> ffi::c_ulong { + let mut auxv: [sys::Elf64_Auxinfo; sys::AT_COUNT as usize] = unsafe { mem::zeroed() }; + + let mut len = core::mem::size_of_val(&auxv) as c_size_t; + + // SAFETY: calling getpid is safe. + let pid = unsafe { sys::getpid() }; + let mib = [ + sys::CTL_KERN as c_int, + sys::KERN_PROC as c_int, + sys::KERN_PROC_AUXV as c_int, + pid, + ]; + + #[allow(clippy::cast_possible_truncation)] + // SAFETY: + // - `mib.len()` does not exceed the size of `mib`. + // - `len` does not exceed the size of `auxv`. + // - `sysctl` is thread-safe. + let res = unsafe { + sys::sysctl( + mib.as_ptr(), + mib.len() as c_uint, + auxv.as_mut_ptr().cast::<c_void>(), + &mut len, + ptr::null_mut(), + 0, + ) + }; + + if res != -1 { + for aux in &auxv { + if aux.a_type == type_ as c_long { + // SAFETY: aux.a_un is #[repr(C)] union and all fields have + // the same size and can be safely transmuted to integers. + return unsafe { aux.a_un.a_val as c_ulong }; + } + } + } + 0 + } + // Similar to the above, but call syscall using asm instead of libc. + // Note that FreeBSD does not guarantee the stability of raw syscall as + // much as Linux does (It may actually be stable enough, though: + // https://lists.llvm.org/pipermail/llvm-dev/2019-June/133393.html, + // https://github.com/ziglang/zig/issues/16590). + // + // This is currently used only for testing. + fn getauxval_sysctl_asm_syscall(type_: ffi::c_int) -> Result<ffi::c_ulong, c_int> { + #[allow(non_camel_case_types)] + type pid_t = c_int; + + // https://github.com/freebsd/freebsd-src/blob/9888a79adad22ba06b5aff17d05abac0029c537a/lib/libc/aarch64/SYS.h + // https://github.com/golang/go/blob/4badad8d477ffd7a6b762c35bc69aed82faface7/src/syscall/asm_freebsd_arm64.s + #[cfg(target_arch = "aarch64")] + #[inline] + fn getpid() -> pid_t { + #[allow(clippy::cast_possible_truncation)] + // SAFETY: calling getpid is safe. + unsafe { + let n = sys::SYS_getpid; + let r: i64; + asm!( + "svc 0", + in("x8") n as u64, + out("x0") r, + options(nostack, readonly), + ); + r as pid_t + } + } + #[cfg(target_arch = "aarch64")] + #[inline] + unsafe fn sysctl( + name: *const c_int, + name_len: c_uint, + old_p: *mut c_void, + old_len_p: *mut c_size_t, + new_p: *const c_void, + new_len: c_size_t, + ) -> Result<c_int, c_int> { + #[allow(clippy::cast_possible_truncation)] + // SAFETY: the caller must uphold the safety contract. + unsafe { + let mut n = sys::SYS___sysctl as u64; + let r: i64; + asm!( + "svc 0", + "b.cc 2f", + "mov x8, x0", + "mov x0, #-1", + "2:", + inout("x8") n, + inout("x0") ptr_reg!(name) => r, + inout("x1") name_len as u64 => _, + in("x2") ptr_reg!(old_p), + in("x3") ptr_reg!(old_len_p), + in("x4") ptr_reg!(new_p), + in("x5") new_len as u64, + options(nostack), + ); + if r as c_int == -1 { + Err(n as c_int) + } else { + Ok(r as c_int) + } + } + } + + // https://github.com/freebsd/freebsd-src/blob/9888a79adad22ba06b5aff17d05abac0029c537a/lib/libc/powerpc64/SYS.h + #[cfg(target_arch = "powerpc64")] + #[inline] + fn getpid() -> pid_t { + #[allow(clippy::cast_possible_truncation)] + // SAFETY: calling getpid is safe. + unsafe { + let n = sys::SYS_getpid; + let r: i64; + asm!( + "sc", + inout("r0") n as u64 => _, + out("r3") r, + out("r4") _, + out("r5") _, + out("r6") _, + out("r7") _, + out("r8") _, + out("r9") _, + out("r10") _, + out("r11") _, + out("r12") _, + out("cr0") _, + options(nostack, preserves_flags, readonly), + ); + r as pid_t + } + } + #[cfg(target_arch = "powerpc64")] + #[inline] + unsafe fn sysctl( + name: *const c_int, + name_len: c_uint, + old_p: *mut c_void, + old_len_p: *mut c_size_t, + new_p: *const c_void, + new_len: c_size_t, + ) -> Result<c_int, c_int> { + #[allow(clippy::cast_possible_truncation)] + // SAFETY: the caller must uphold the safety contract. + unsafe { + let mut n = sys::SYS___sysctl as u64; + let r: i64; + asm!( + "sc", + "bns+ 2f", + "mr %r0, %r3", + "li %r3, -1", + "2:", + inout("r0") n, + inout("r3") ptr_reg!(name) => r, + inout("r4") name_len as u64 => _, + inout("r5") ptr_reg!(old_p) => _, + inout("r6") ptr_reg!(old_len_p) => _, + inout("r7") ptr_reg!(new_p) => _, + inout("r8") new_len as u64 => _, + out("r9") _, + out("r10") _, + out("r11") _, + out("r12") _, + out("cr0") _, + options(nostack, preserves_flags) + ); + if r as c_int == -1 { + Err(n as c_int) + } else { + Ok(r as c_int) + } + } + } + + let mut auxv: [sys::Elf64_Auxinfo; sys::AT_COUNT as usize] = unsafe { mem::zeroed() }; + + let mut len = core::mem::size_of_val(&auxv) as c_size_t; + + let pid = getpid(); + let mib = [ + sys::CTL_KERN as c_int, + sys::KERN_PROC as c_int, + sys::KERN_PROC_AUXV as c_int, + pid, + ]; + + #[allow(clippy::cast_possible_truncation)] + // SAFETY: + // - `mib.len()` does not exceed the size of `mib`. + // - `len` does not exceed the size of `auxv`. + // - `sysctl` is thread-safe. + unsafe { + sysctl( + mib.as_ptr(), + mib.len() as c_uint, + auxv.as_mut_ptr().cast::<c_void>(), + &mut len, + ptr::null_mut(), + 0, + )?; + } + + for aux in &auxv { + if aux.a_type == type_ as c_long { + // SAFETY: aux.a_un is #[repr(C)] union and all fields have + // the same size and can be safely transmuted to integers. + return Ok(unsafe { aux.a_un.a_val as c_ulong }); + } + } + Err(0) + } + + assert_eq!(os::getauxval(ffi::AT_HWCAP), getauxval_sysctl_libc(ffi::AT_HWCAP)); + assert_eq!(os::getauxval(ffi::AT_HWCAP2), getauxval_sysctl_libc(ffi::AT_HWCAP2)); + assert_eq!( + os::getauxval(ffi::AT_HWCAP), + getauxval_sysctl_asm_syscall(ffi::AT_HWCAP).unwrap() + ); + assert_eq!( + os::getauxval(ffi::AT_HWCAP2), + // AT_HWCAP2 is only available on FreeBSD 13+, at least for aarch64. + getauxval_sysctl_asm_syscall(ffi::AT_HWCAP2).unwrap_or(0) + ); + } + + // Static assertions for FFI bindings. + // This checks that FFI bindings defined in this crate, FFI bindings defined + // in libc, 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::{libc, sys}; + #[cfg(not(target_os = "freebsd"))] + type AtType = ffi::c_ulong; + #[cfg(target_os = "freebsd")] + type AtType = ffi::c_int; + #[cfg(any(target_os = "linux", target_os = "android"))] + { + let mut _getauxval: unsafe extern "C" fn(ffi::c_ulong) -> ffi::c_ulong = ffi::getauxval; + _getauxval = libc::getauxval; + _getauxval = sys::getauxval; + } + #[cfg(all(target_arch = "aarch64", target_os = "android"))] + { + let mut ___system_property_get: unsafe extern "C" fn( + *const ffi::c_char, + *mut ffi::c_char, + ) -> ffi::c_int = ffi::__system_property_get; + ___system_property_get = libc::__system_property_get; + ___system_property_get = sys::__system_property_get; + static_assert!(ffi::PROP_VALUE_MAX == libc::PROP_VALUE_MAX); + static_assert!(ffi::PROP_VALUE_MAX == sys::PROP_VALUE_MAX as ffi::c_int); + } + #[cfg(target_os = "freebsd")] + { + let mut _elf_aux_info: unsafe extern "C" fn( + ffi::c_int, + *mut ffi::c_void, + ffi::c_int, + ) -> ffi::c_int = ffi::elf_aux_info; + _elf_aux_info = libc::elf_aux_info; + _elf_aux_info = sys::elf_aux_info; + } + #[cfg(not(target_os = "freebsd"))] // libc doesn't have this on FreeBSD + static_assert!(ffi::AT_HWCAP == libc::AT_HWCAP); + static_assert!(ffi::AT_HWCAP == sys::AT_HWCAP as AtType); + #[cfg(not(target_os = "freebsd"))] // libc doesn't have this on FreeBSD + static_assert!(ffi::AT_HWCAP2 == libc::AT_HWCAP2); + static_assert!(ffi::AT_HWCAP2 == sys::AT_HWCAP2 as AtType); + #[cfg(target_arch = "aarch64")] + { + // static_assert!(arch::HWCAP_ATOMICS == libc::HWCAP_ATOMICS); // libc doesn't have this + static_assert!(arch::HWCAP_ATOMICS == sys::HWCAP_ATOMICS as ffi::c_ulong); + // static_assert!(HWCAP_USCAT == libc::HWCAP_USCAT); // libc doesn't have this + static_assert!(arch::HWCAP_USCAT == sys::HWCAP_USCAT as ffi::c_ulong); + #[cfg(any(target_os = "linux", target_os = "android"))] + #[cfg(target_pointer_width = "64")] + { + // static_assert!(HWCAP2_LRCPC3 == libc::HWCAP2_LRCPC3); // libc doesn't have this + static_assert!(arch::HWCAP2_LRCPC3 == sys::HWCAP2_LRCPC3 as ffi::c_ulong); + // static_assert!(HWCAP2_LSE128 == libc::HWCAP2_LSE128); // libc doesn't have this + static_assert!(arch::HWCAP2_LSE128 == sys::HWCAP2_LSE128 as ffi::c_ulong); + } + } + #[cfg(target_arch = "powerpc64")] + { + // static_assert!(arch::PPC_FEATURE2_ARCH_2_07 == libc::PPC_FEATURE2_ARCH_2_07); // libc doesn't have this + static_assert!( + arch::PPC_FEATURE2_ARCH_2_07 == sys::PPC_FEATURE2_ARCH_2_07 as ffi::c_ulong + ); + } + }; +} |