From 1b6a04ca5504955c571d1c97504fb45ea0befee4 Mon Sep 17 00:00:00 2001
From: Valentin Popov <valentin@popov.link>
Date: Mon, 8 Jan 2024 01:21:28 +0400
Subject: Initial vendor packages
Signed-off-by: Valentin Popov <valentin@popov.link>
---
.../rustix/src/backend/linux_raw/vdso_wrappers.rs | 608 +++++++++++++++++++++
1 file changed, 608 insertions(+)
create mode 100644 vendor/rustix/src/backend/linux_raw/vdso_wrappers.rs
(limited to 'vendor/rustix/src/backend/linux_raw/vdso_wrappers.rs')
diff --git a/vendor/rustix/src/backend/linux_raw/vdso_wrappers.rs b/vendor/rustix/src/backend/linux_raw/vdso_wrappers.rs
new file mode 100644
index 0000000..441738f
--- /dev/null
+++ b/vendor/rustix/src/backend/linux_raw/vdso_wrappers.rs
@@ -0,0 +1,608 @@
+//! Implement syscalls using the vDSO.
+//!
+//! <https://man7.org/linux/man-pages/man7/vdso.7.html>
+//!
+//! # Safety
+//!
+//! Similar to syscalls.rs, this file performs raw system calls, and sometimes
+//! passes them uninitialized memory buffers. This file also calls vDSO
+//! functions.
+#![allow(unsafe_code)]
+
+#[cfg(target_arch = "x86")]
+use super::reg::{ArgReg, RetReg, SyscallNumber, A0, A1, A2, A3, A4, A5, R0};
+use super::vdso;
+#[cfg(target_arch = "x86")]
+use core::arch::global_asm;
+#[cfg(feature = "process")]
+#[cfg(any(
+ target_arch = "x86_64",
+ target_arch = "x86",
+ target_arch = "riscv64",
+ target_arch = "powerpc64"
+))]
+use core::ffi::c_void;
+use core::mem::transmute;
+use core::ptr::null_mut;
+use core::sync::atomic::AtomicPtr;
+use core::sync::atomic::Ordering::Relaxed;
+#[cfg(target_pointer_width = "32")]
+#[cfg(feature = "time")]
+use linux_raw_sys::general::timespec as __kernel_old_timespec;
+#[cfg(any(
+ all(
+ feature = "process",
+ any(
+ target_arch = "x86_64",
+ target_arch = "x86",
+ target_arch = "riscv64",
+ target_arch = "powerpc64"
+ )
+ ),
+ feature = "time"
+))]
+use {super::c, super::conv::ret, core::mem::MaybeUninit};
+#[cfg(feature = "time")]
+use {
+ super::conv::c_int,
+ crate::clockid::{ClockId, DynamicClockId},
+ crate::io,
+ crate::timespec::Timespec,
+ linux_raw_sys::general::{__kernel_clockid_t, __kernel_timespec},
+};
+
+#[cfg(feature = "time")]
+#[inline]
+pub(crate) fn clock_gettime(which_clock: ClockId) -> __kernel_timespec {
+ // SAFETY: `CLOCK_GETTIME` contains either null or the address of a
+ // function with an ABI like libc `clock_gettime`, and calling it has the
+ // side effect of writing to the result buffer, and no others.
+ unsafe {
+ let mut result = MaybeUninit::<__kernel_timespec>::uninit();
+ let callee = match transmute(CLOCK_GETTIME.load(Relaxed)) {
+ Some(callee) => callee,
+ None => init_clock_gettime(),
+ };
+ let r0 = callee(which_clock as c::c_int, result.as_mut_ptr());
+ // The `ClockId` enum only contains clocks which never fail. It may be
+ // tempting to change this to `debug_assert_eq`, however they can still
+ // fail on uncommon kernel configs, so we leave this in place to ensure
+ // that we don't execute undefined behavior if they ever do fail.
+ assert_eq!(r0, 0);
+ result.assume_init()
+ }
+}
+
+#[cfg(feature = "time")]
+#[inline]
+pub(crate) fn clock_gettime_dynamic(which_clock: DynamicClockId<'_>) -> io::Result<Timespec> {
+ let id = match which_clock {
+ DynamicClockId::Known(id) => id as __kernel_clockid_t,
+
+ DynamicClockId::Dynamic(fd) => {
+ // See `FD_TO_CLOCKID` in Linux's `clock_gettime` documentation.
+ use crate::backend::fd::AsRawFd;
+ const CLOCKFD: i32 = 3;
+ ((!fd.as_raw_fd() << 3) | CLOCKFD) as __kernel_clockid_t
+ }
+
+ DynamicClockId::RealtimeAlarm => c::CLOCK_REALTIME_ALARM as __kernel_clockid_t,
+ DynamicClockId::Tai => c::CLOCK_TAI as __kernel_clockid_t,
+ DynamicClockId::Boottime => c::CLOCK_BOOTTIME as __kernel_clockid_t,
+ DynamicClockId::BoottimeAlarm => c::CLOCK_BOOTTIME_ALARM as __kernel_clockid_t,
+ };
+
+ // SAFETY: `CLOCK_GETTIME` contains either null or the address of a
+ // function with an ABI like libc `clock_gettime`, and calling it has the
+ // side effect of writing to the result buffer, and no others.
+ unsafe {
+ const EINVAL: c::c_int = -(c::EINVAL as c::c_int);
+ let mut timespec = MaybeUninit::<Timespec>::uninit();
+ let callee = match transmute(CLOCK_GETTIME.load(Relaxed)) {
+ Some(callee) => callee,
+ None => init_clock_gettime(),
+ };
+ match callee(id, timespec.as_mut_ptr()) {
+ 0 => (),
+ EINVAL => return Err(io::Errno::INVAL),
+ _ => _rustix_clock_gettime_via_syscall(id, timespec.as_mut_ptr())?,
+ }
+ Ok(timespec.assume_init())
+ }
+}
+
+#[cfg(feature = "process")]
+#[cfg(any(
+ target_arch = "x86_64",
+ target_arch = "x86",
+ target_arch = "riscv64",
+ target_arch = "powerpc64"
+))]
+#[inline]
+pub(crate) fn sched_getcpu() -> usize {
+ // SAFETY: `GETCPU` contains either null or the address of a function with
+ // an ABI like libc `getcpu`, and calling it has the side effect of writing
+ // to the result buffers, and no others.
+ unsafe {
+ let mut cpu = MaybeUninit::<u32>::uninit();
+ let callee = match transmute(GETCPU.load(Relaxed)) {
+ Some(callee) => callee,
+ None => init_getcpu(),
+ };
+ let r0 = callee(cpu.as_mut_ptr(), null_mut(), null_mut());
+ debug_assert_eq!(r0, 0);
+ cpu.assume_init() as usize
+ }
+}
+
+#[cfg(target_arch = "x86")]
+pub(super) mod x86_via_vdso {
+ use super::{transmute, ArgReg, Relaxed, RetReg, SyscallNumber, A0, A1, A2, A3, A4, A5, R0};
+ use crate::backend::arch::asm;
+
+ #[inline]
+ pub(in crate::backend) unsafe fn syscall0(nr: SyscallNumber<'_>) -> RetReg<R0> {
+ let callee = match transmute(super::SYSCALL.load(Relaxed)) {
+ Some(callee) => callee,
+ None => super::init_syscall(),
+ };
+ asm::indirect_syscall0(callee, nr)
+ }
+
+ #[inline]
+ pub(in crate::backend) unsafe fn syscall1<'a>(
+ nr: SyscallNumber<'a>,
+ a0: ArgReg<'a, A0>,
+ ) -> RetReg<R0> {
+ let callee = match transmute(super::SYSCALL.load(Relaxed)) {
+ Some(callee) => callee,
+ None => super::init_syscall(),
+ };
+ asm::indirect_syscall1(callee, nr, a0)
+ }
+
+ #[inline]
+ pub(in crate::backend) unsafe fn syscall1_noreturn<'a>(
+ nr: SyscallNumber<'a>,
+ a0: ArgReg<'a, A0>,
+ ) -> ! {
+ let callee = match transmute(super::SYSCALL.load(Relaxed)) {
+ Some(callee) => callee,
+ None => super::init_syscall(),
+ };
+ asm::indirect_syscall1_noreturn(callee, nr, a0)
+ }
+
+ #[inline]
+ pub(in crate::backend) unsafe fn syscall2<'a>(
+ nr: SyscallNumber<'a>,
+ a0: ArgReg<'a, A0>,
+ a1: ArgReg<'a, A1>,
+ ) -> RetReg<R0> {
+ let callee = match transmute(super::SYSCALL.load(Relaxed)) {
+ Some(callee) => callee,
+ None => super::init_syscall(),
+ };
+ asm::indirect_syscall2(callee, nr, a0, a1)
+ }
+
+ #[inline]
+ pub(in crate::backend) unsafe fn syscall3<'a>(
+ nr: SyscallNumber<'a>,
+ a0: ArgReg<'a, A0>,
+ a1: ArgReg<'a, A1>,
+ a2: ArgReg<'a, A2>,
+ ) -> RetReg<R0> {
+ let callee = match transmute(super::SYSCALL.load(Relaxed)) {
+ Some(callee) => callee,
+ None => super::init_syscall(),
+ };
+ asm::indirect_syscall3(callee, nr, a0, a1, a2)
+ }
+
+ #[inline]
+ pub(in crate::backend) unsafe fn syscall4<'a>(
+ nr: SyscallNumber<'a>,
+ a0: ArgReg<'a, A0>,
+ a1: ArgReg<'a, A1>,
+ a2: ArgReg<'a, A2>,
+ a3: ArgReg<'a, A3>,
+ ) -> RetReg<R0> {
+ let callee = match transmute(super::SYSCALL.load(Relaxed)) {
+ Some(callee) => callee,
+ None => super::init_syscall(),
+ };
+ asm::indirect_syscall4(callee, nr, a0, a1, a2, a3)
+ }
+
+ #[inline]
+ pub(in crate::backend) unsafe fn syscall5<'a>(
+ nr: SyscallNumber<'a>,
+ a0: ArgReg<'a, A0>,
+ a1: ArgReg<'a, A1>,
+ a2: ArgReg<'a, A2>,
+ a3: ArgReg<'a, A3>,
+ a4: ArgReg<'a, A4>,
+ ) -> RetReg<R0> {
+ let callee = match transmute(super::SYSCALL.load(Relaxed)) {
+ Some(callee) => callee,
+ None => super::init_syscall(),
+ };
+ asm::indirect_syscall5(callee, nr, a0, a1, a2, a3, a4)
+ }
+
+ #[inline]
+ pub(in crate::backend) unsafe fn syscall6<'a>(
+ nr: SyscallNumber<'a>,
+ a0: ArgReg<'a, A0>,
+ a1: ArgReg<'a, A1>,
+ a2: ArgReg<'a, A2>,
+ a3: ArgReg<'a, A3>,
+ a4: ArgReg<'a, A4>,
+ a5: ArgReg<'a, A5>,
+ ) -> RetReg<R0> {
+ let callee = match transmute(super::SYSCALL.load(Relaxed)) {
+ Some(callee) => callee,
+ None => super::init_syscall(),
+ };
+ asm::indirect_syscall6(callee, nr, a0, a1, a2, a3, a4, a5)
+ }
+
+ // With the indirect call, it isn't meaningful to do a separate
+ // `_readonly` optimization.
+ #[allow(unused_imports)]
+ pub(in crate::backend) use {
+ syscall0 as syscall0_readonly, syscall1 as syscall1_readonly,
+ syscall2 as syscall2_readonly, syscall3 as syscall3_readonly,
+ syscall4 as syscall4_readonly, syscall5 as syscall5_readonly,
+ syscall6 as syscall6_readonly,
+ };
+}
+
+#[cfg(feature = "time")]
+type ClockGettimeType = unsafe extern "C" fn(c::c_int, *mut Timespec) -> c::c_int;
+
+#[cfg(feature = "process")]
+#[cfg(any(
+ target_arch = "x86_64",
+ target_arch = "x86",
+ target_arch = "riscv64",
+ target_arch = "powerpc64"
+))]
+type GetcpuType = unsafe extern "C" fn(*mut u32, *mut u32, *mut c_void) -> c::c_int;
+
+/// The underlying syscall functions are only called from asm, using the
+/// special syscall calling convention to pass arguments and return values,
+/// which the signature here doesn't reflect.
+#[cfg(target_arch = "x86")]
+pub(super) type SyscallType = unsafe extern "C" fn();
+
+/// Initialize `CLOCK_GETTIME` and return its value.
+#[cfg(feature = "time")]
+#[cold]
+fn init_clock_gettime() -> ClockGettimeType {
+ init();
+ // SAFETY: Load the function address from static storage that we just
+ // initialized.
+ unsafe { transmute(CLOCK_GETTIME.load(Relaxed)) }
+}
+
+/// Initialize `GETCPU` and return its value.
+#[cfg(feature = "process")]
+#[cfg(any(
+ target_arch = "x86_64",
+ target_arch = "x86",
+ target_arch = "riscv64",
+ target_arch = "powerpc64"
+))]
+#[cold]
+fn init_getcpu() -> GetcpuType {
+ init();
+ // SAFETY: Load the function address from static storage that we just
+ // initialized.
+ unsafe { transmute(GETCPU.load(Relaxed)) }
+}
+
+/// Initialize `SYSCALL` and return its value.
+#[cfg(target_arch = "x86")]
+#[cold]
+fn init_syscall() -> SyscallType {
+ init();
+ // SAFETY: Load the function address from static storage that we just
+ // initialized.
+ unsafe { transmute(SYSCALL.load(Relaxed)) }
+}
+
+/// `AtomicPtr` can't hold a `fn` pointer, so we use a `*` pointer to this
+/// placeholder type, and cast it as needed.
+struct Function;
+#[cfg(feature = "time")]
+static mut CLOCK_GETTIME: AtomicPtr<Function> = AtomicPtr::new(null_mut());
+#[cfg(feature = "process")]
+#[cfg(any(
+ target_arch = "x86_64",
+ target_arch = "x86",
+ target_arch = "riscv64",
+ target_arch = "powerpc64"
+))]
+static mut GETCPU: AtomicPtr<Function> = AtomicPtr::new(null_mut());
+#[cfg(target_arch = "x86")]
+static mut SYSCALL: AtomicPtr<Function> = AtomicPtr::new(null_mut());
+
+#[cfg(feature = "time")]
+unsafe extern "C" fn rustix_clock_gettime_via_syscall(
+ clockid: c::c_int,
+ res: *mut Timespec,
+) -> c::c_int {
+ match _rustix_clock_gettime_via_syscall(clockid, res) {
+ Ok(()) => 0,
+ Err(err) => err.raw_os_error().wrapping_neg(),
+ }
+}
+
+#[cfg(feature = "time")]
+#[cfg(target_pointer_width = "32")]
+unsafe fn _rustix_clock_gettime_via_syscall(
+ clockid: c::c_int,
+ res: *mut Timespec,
+) -> io::Result<()> {
+ let r0 = syscall!(__NR_clock_gettime64, c_int(clockid), res);
+ match ret(r0) {
+ Err(io::Errno::NOSYS) => _rustix_clock_gettime_via_syscall_old(clockid, res),
+ otherwise => otherwise,
+ }
+}
+
+#[cfg(feature = "time")]
+#[cfg(target_pointer_width = "32")]
+unsafe fn _rustix_clock_gettime_via_syscall_old(
+ clockid: c::c_int,
+ res: *mut Timespec,
+) -> io::Result<()> {
+ // Ordinarily `rustix` doesn't like to emulate system calls, but in the
+ // case of time APIs, it's specific to Linux, specific to 32-bit
+ // architectures *and* specific to old kernel versions, and it's not that
+ // hard to fix up here, so that no other code needs to worry about this.
+ let mut old_result = MaybeUninit::<__kernel_old_timespec>::uninit();
+ let r0 = syscall!(__NR_clock_gettime, c_int(clockid), &mut old_result);
+ match ret(r0) {
+ Ok(()) => {
+ let old_result = old_result.assume_init();
+ *res = Timespec {
+ tv_sec: old_result.tv_sec.into(),
+ tv_nsec: old_result.tv_nsec.into(),
+ };
+ Ok(())
+ }
+ otherwise => otherwise,
+ }
+}
+
+#[cfg(feature = "time")]
+#[cfg(target_pointer_width = "64")]
+unsafe fn _rustix_clock_gettime_via_syscall(
+ clockid: c::c_int,
+ res: *mut Timespec,
+) -> io::Result<()> {
+ ret(syscall!(__NR_clock_gettime, c_int(clockid), res))
+}
+
+#[cfg(feature = "process")]
+#[cfg(any(
+ target_arch = "x86_64",
+ target_arch = "x86",
+ target_arch = "riscv64",
+ target_arch = "powerpc64"
+))]
+unsafe extern "C" fn rustix_getcpu_via_syscall(
+ cpu: *mut u32,
+ node: *mut u32,
+ unused: *mut c_void,
+) -> c::c_int {
+ match ret(syscall!(__NR_getcpu, cpu, node, unused)) {
+ Ok(()) => 0,
+ Err(err) => err.raw_os_error().wrapping_neg(),
+ }
+}
+
+#[cfg(target_arch = "x86")]
+extern "C" {
+ /// A symbol pointing to an `int 0x80` instruction. This “function” is only
+ /// called from assembly, and only with the x86 syscall calling convention,
+ /// so its signature here is not its true signature.
+ ///
+ /// This extern block and the `global_asm!` below can be replaced with
+ /// `#[naked]` if it's stabilized.
+ fn rustix_int_0x80();
+}
+
+#[cfg(target_arch = "x86")]
+global_asm!(
+ r#"
+ .section .text.rustix_int_0x80,"ax",@progbits
+ .p2align 4
+ .weak rustix_int_0x80
+ .hidden rustix_int_0x80
+ .type rustix_int_0x80, @function
+rustix_int_0x80:
+ .cfi_startproc
+ int 0x80
+ ret
+ .cfi_endproc
+ .size rustix_int_0x80, .-rustix_int_0x80
+"#
+);
+
+fn minimal_init() {
+ // SAFETY: Store default function addresses in static storage so that if we
+ // end up making any system calls while we read the vDSO, they'll work. If
+ // the memory happens to already be initialized, this is redundant, but not
+ // harmful.
+ unsafe {
+ #[cfg(feature = "time")]
+ {
+ CLOCK_GETTIME
+ .compare_exchange(
+ null_mut(),
+ rustix_clock_gettime_via_syscall as *mut Function,
+ Relaxed,
+ Relaxed,
+ )
+ .ok();
+ }
+
+ #[cfg(feature = "process")]
+ #[cfg(any(
+ target_arch = "x86_64",
+ target_arch = "x86",
+ target_arch = "riscv64",
+ target_arch = "powerpc64"
+ ))]
+ {
+ GETCPU
+ .compare_exchange(
+ null_mut(),
+ rustix_getcpu_via_syscall as *mut Function,
+ Relaxed,
+ Relaxed,
+ )
+ .ok();
+ }
+
+ #[cfg(target_arch = "x86")]
+ {
+ SYSCALL
+ .compare_exchange(
+ null_mut(),
+ rustix_int_0x80 as *mut Function,
+ Relaxed,
+ Relaxed,
+ )
+ .ok();
+ }
+ }
+}
+
+fn init() {
+ minimal_init();
+
+ if let Some(vdso) = vdso::Vdso::new() {
+ #[cfg(feature = "time")]
+ {
+ // Look up the platform-specific `clock_gettime` symbol as
+ // documented [here], except on 32-bit platforms where we look up
+ // the `64`-suffixed variant and fail if we don't find it.
+ //
+ // [here]: https://man7.org/linux/man-pages/man7/vdso.7.html
+ #[cfg(target_arch = "x86_64")]
+ let ptr = vdso.sym(cstr!("LINUX_2.6"), cstr!("__vdso_clock_gettime"));
+ #[cfg(target_arch = "arm")]
+ let ptr = vdso.sym(cstr!("LINUX_2.6"), cstr!("__vdso_clock_gettime64"));
+ #[cfg(target_arch = "aarch64")]
+ let ptr = vdso.sym(cstr!("LINUX_2.6.39"), cstr!("__kernel_clock_gettime"));
+ #[cfg(target_arch = "x86")]
+ let ptr = vdso.sym(cstr!("LINUX_2.6"), cstr!("__vdso_clock_gettime64"));
+ #[cfg(target_arch = "riscv64")]
+ let ptr = vdso.sym(cstr!("LINUX_4.15"), cstr!("__vdso_clock_gettime"));
+ #[cfg(target_arch = "powerpc64")]
+ let ptr = vdso.sym(cstr!("LINUX_2.6.15"), cstr!("__kernel_clock_gettime"));
+ #[cfg(any(target_arch = "mips", target_arch = "mips32r6"))]
+ let ptr = vdso.sym(cstr!("LINUX_2.6"), cstr!("__vdso_clock_gettime64"));
+ #[cfg(any(target_arch = "mips64", target_arch = "mips64r6"))]
+ let ptr = vdso.sym(cstr!("LINUX_2.6"), cstr!("__vdso_clock_gettime"));
+
+ // On all 64-bit platforms, the 64-bit `clock_gettime` symbols are
+ // always available.
+ #[cfg(target_pointer_width = "64")]
+ let ok = true;
+
+ // On some 32-bit platforms, the 64-bit `clock_gettime` symbols are
+ // not available on older kernel versions.
+ #[cfg(any(
+ target_arch = "arm",
+ target_arch = "mips",
+ target_arch = "mips32r6",
+ target_arch = "x86"
+ ))]
+ let ok = !ptr.is_null();
+
+ if ok {
+ assert!(!ptr.is_null());
+
+ // SAFETY: Store the computed function addresses in static
+ // storage so that we don't need to compute it again (but if
+ // we do, it doesn't hurt anything).
+ unsafe {
+ CLOCK_GETTIME.store(ptr.cast(), Relaxed);
+ }
+ }
+ }
+
+ #[cfg(feature = "process")]
+ #[cfg(any(
+ target_arch = "x86_64",
+ target_arch = "x86",
+ target_arch = "riscv64",
+ target_arch = "powerpc64"
+ ))]
+ {
+ // Look up the platform-specific `getcpu` symbol as documented
+ // [here].
+ //
+ // [here]: https://man7.org/linux/man-pages/man7/vdso.7.html
+ #[cfg(target_arch = "x86_64")]
+ let ptr = vdso.sym(cstr!("LINUX_2.6"), cstr!("__vdso_getcpu"));
+ #[cfg(target_arch = "x86")]
+ let ptr = vdso.sym(cstr!("LINUX_2.6"), cstr!("__vdso_getcpu"));
+ #[cfg(target_arch = "riscv64")]
+ let ptr = vdso.sym(cstr!("LINUX_4.15"), cstr!("__kernel_getcpu"));
+ #[cfg(target_arch = "powerpc64")]
+ let ptr = vdso.sym(cstr!("LINUX_2.6.15"), cstr!("__kernel_getcpu"));
+
+ #[cfg(any(
+ target_arch = "x86_64",
+ target_arch = "riscv64",
+ target_arch = "powerpc64"
+ ))]
+ let ok = true;
+
+ // On 32-bit x86, the symbol doesn't appear present sometimes.
+ #[cfg(target_arch = "x86")]
+ let ok = !ptr.is_null();
+
+ #[cfg(any(
+ target_arch = "aarch64",
+ target_arch = "arm",
+ target_arch = "mips",
+ target_arch = "mips32r6",
+ target_arch = "mips64",
+ target_arch = "mips64r6"
+ ))]
+ let ok = false;
+
+ if ok {
+ assert!(!ptr.is_null());
+
+ // SAFETY: Store the computed function addresses in static
+ // storage so that we don't need to compute it again (but if
+ // we do, it doesn't hurt anything).
+ unsafe {
+ GETCPU.store(ptr.cast(), Relaxed);
+ }
+ }
+ }
+
+ // On x86, also look up the vsyscall entry point.
+ #[cfg(target_arch = "x86")]
+ {
+ let ptr = vdso.sym(cstr!("LINUX_2.5"), cstr!("__kernel_vsyscall"));
+ assert!(!ptr.is_null());
+
+ // SAFETY: As above, store the computed function addresses in
+ // static storage.
+ unsafe {
+ SYSCALL.store(ptr.cast(), Relaxed);
+ }
+ }
+ }
+}
--
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