sourceturner
76 lines
1.9 KiB
Rust
76 lines
1.9 KiB
Rust
use core::sync::atomic::{AtomicI32 as AtomicInt, Ordering};
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use crate::header::errno::EBUSY;
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use super::*;
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const UNLOCKED: c_int = 0;
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const LOCKED: c_int = 1;
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#[unsafe(no_mangle)]
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pub unsafe extern "C" fn pthread_spin_destroy(spinlock: *mut pthread_spinlock_t) -> c_int {
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let _spinlock = unsafe { &mut *spinlock.cast::<RlctSpinlock>() };
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// No-op
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0
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}
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#[unsafe(no_mangle)]
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pub unsafe extern "C" fn pthread_spin_init(
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spinlock: *mut pthread_spinlock_t,
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_pshared: c_int,
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) -> c_int {
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// TODO: pshared doesn't matter in most situations, as memory is just memory, but this may be
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// different on some architectures...
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unsafe {
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spinlock.cast::<RlctSpinlock>().write(RlctSpinlock {
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inner: AtomicInt::new(UNLOCKED),
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})
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};
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0
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}
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#[unsafe(no_mangle)]
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pub unsafe extern "C" fn pthread_spin_lock(spinlock: *mut pthread_spinlock_t) -> c_int {
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let spinlock = unsafe { &*spinlock.cast::<RlctSpinlock>() };
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loop {
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match spinlock.inner.compare_exchange_weak(
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UNLOCKED,
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LOCKED,
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Ordering::Acquire,
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Ordering::Relaxed,
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) {
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Ok(_) => break,
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Err(_) => core::hint::spin_loop(),
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}
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}
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0
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}
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#[unsafe(no_mangle)]
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pub unsafe extern "C" fn pthread_spin_trylock(spinlock: *mut pthread_spinlock_t) -> c_int {
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let spinlock = unsafe { &*spinlock.cast::<RlctSpinlock>() };
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match spinlock
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.inner
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.compare_exchange(UNLOCKED, LOCKED, Ordering::Acquire, Ordering::Relaxed)
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{
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Ok(_) => (),
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Err(_) => return EBUSY,
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}
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0
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}
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#[unsafe(no_mangle)]
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pub unsafe extern "C" fn pthread_spin_unlock(spinlock: *mut pthread_spinlock_t) -> c_int {
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let spinlock = unsafe { &*spinlock.cast::<RlctSpinlock>() };
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spinlock.inner.store(UNLOCKED, Ordering::Release);
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0
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}
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pub(crate) struct RlctSpinlock {
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pub inner: AtomicInt,
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}
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