summaryrefslogtreecommitdiff
path: root/lib/mlibc/options/internal/generic/threads.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'lib/mlibc/options/internal/generic/threads.cpp')
-rw-r--r--lib/mlibc/options/internal/generic/threads.cpp342
1 files changed, 0 insertions, 342 deletions
diff --git a/lib/mlibc/options/internal/generic/threads.cpp b/lib/mlibc/options/internal/generic/threads.cpp
deleted file mode 100644
index 5f1168c..0000000
--- a/lib/mlibc/options/internal/generic/threads.cpp
+++ /dev/null
@@ -1,342 +0,0 @@
-#include <abi-bits/errno.h>
-#include <bits/threads.h>
-#include <bits/ensure.h>
-#include <mlibc/all-sysdeps.hpp>
-#include <mlibc/debug.hpp>
-#include <mlibc/lock.hpp>
-#include <mlibc/threads.hpp>
-#include <mlibc/tcb.hpp>
-
-extern "C" Tcb *__rtdl_allocateTcb();
-
-namespace mlibc {
-
-int thread_create(struct __mlibc_thread_data **__restrict thread, const struct __mlibc_threadattr *__restrict attrp, void *entry, void *__restrict user_arg, bool returns_int) {
- auto new_tcb = __rtdl_allocateTcb();
- pid_t tid;
- struct __mlibc_threadattr attr = {};
- if (!attrp)
- thread_attr_init(&attr);
- else
- attr = *attrp;
-
- if (attr.__mlibc_cpuset)
- mlibc::infoLogger() << "pthread_create(): cpuset is ignored!" << frg::endlog;
- if (attr.__mlibc_sigmaskset)
- mlibc::infoLogger() << "pthread_create(): sigmask is ignored!" << frg::endlog;
-
- // TODO: due to alignment guarantees, the stackaddr and stacksize might change
- // when the stack is allocated. Currently this isn't propagated to the TCB,
- // but it should be.
- void *stack = attr.__mlibc_stackaddr;
- if (!mlibc::sys_prepare_stack) {
- MLIBC_MISSING_SYSDEP();
- return ENOSYS;
- }
- int ret = mlibc::sys_prepare_stack(&stack, entry,
- user_arg, new_tcb, &attr.__mlibc_stacksize, &attr.__mlibc_guardsize, &new_tcb->stackAddr);
- if (ret)
- return ret;
-
- if (!mlibc::sys_clone) {
- MLIBC_MISSING_SYSDEP();
- return ENOSYS;
- }
- new_tcb->stackSize = attr.__mlibc_stacksize;
- new_tcb->guardSize = attr.__mlibc_guardsize;
- new_tcb->returnValueType = (returns_int) ? TcbThreadReturnValue::Integer : TcbThreadReturnValue::Pointer;
- mlibc::sys_clone(new_tcb, &tid, stack);
- *thread = reinterpret_cast<struct __mlibc_thread_data *>(new_tcb);
-
- __atomic_store_n(&new_tcb->tid, tid, __ATOMIC_RELAXED);
- mlibc::sys_futex_wake(&new_tcb->tid);
-
- return 0;
-}
-
-int thread_join(struct __mlibc_thread_data *thread, void *ret) {
- auto tcb = reinterpret_cast<Tcb *>(thread);
-
- if (!__atomic_load_n(&tcb->isJoinable, __ATOMIC_ACQUIRE))
- return EINVAL;
-
- while (!__atomic_load_n(&tcb->didExit, __ATOMIC_ACQUIRE)) {
- mlibc::sys_futex_wait(&tcb->didExit, 0, nullptr);
- }
-
- if(ret && tcb->returnValueType == TcbThreadReturnValue::Pointer)
- *reinterpret_cast<void **>(ret) = tcb->returnValue.voidPtr;
- else if(ret && tcb->returnValueType == TcbThreadReturnValue::Integer)
- *reinterpret_cast<int *>(ret) = tcb->returnValue.intVal;
-
- // FIXME: destroy tcb here, currently we leak it
-
- return 0;
-}
-
-static constexpr size_t default_stacksize = 0x200000;
-static constexpr size_t default_guardsize = 4096;
-
-int thread_attr_init(struct __mlibc_threadattr *attr) {
- *attr = __mlibc_threadattr{};
- attr->__mlibc_stacksize = default_stacksize;
- attr->__mlibc_guardsize = default_guardsize;
- attr->__mlibc_detachstate = __MLIBC_THREAD_CREATE_JOINABLE;
- return 0;
-}
-
-static constexpr unsigned int mutexRecursive = 1;
-static constexpr unsigned int mutexErrorCheck = 2;
-
-// TODO: either use uint32_t or determine the bit based on sizeof(int).
-static constexpr unsigned int mutex_owner_mask = (static_cast<uint32_t>(1) << 30) - 1;
-static constexpr unsigned int mutex_waiters_bit = static_cast<uint32_t>(1) << 31;
-
-// Only valid for the internal __mlibc_m mutex of wrlocks.
-static constexpr unsigned int mutex_excl_bit = static_cast<uint32_t>(1) << 30;
-
-int thread_mutex_init(struct __mlibc_mutex *__restrict mutex,
- const struct __mlibc_mutexattr *__restrict attr) {
- auto type = attr ? attr->__mlibc_type : __MLIBC_THREAD_MUTEX_DEFAULT;
- auto robust = attr ? attr->__mlibc_robust : __MLIBC_THREAD_MUTEX_STALLED;
- auto protocol = attr ? attr->__mlibc_protocol : __MLIBC_THREAD_PRIO_NONE;
- auto pshared = attr ? attr->__mlibc_pshared : __MLIBC_THREAD_PROCESS_PRIVATE;
-
- mutex->__mlibc_state = 0;
- mutex->__mlibc_recursion = 0;
- mutex->__mlibc_flags = 0;
- mutex->__mlibc_prioceiling = 0; // TODO: We don't implement this.
-
- if(type == __MLIBC_THREAD_MUTEX_RECURSIVE) {
- mutex->__mlibc_flags |= mutexRecursive;
- }else if(type == __MLIBC_THREAD_MUTEX_ERRORCHECK) {
- mutex->__mlibc_flags |= mutexErrorCheck;
- }else{
- __ensure(type == __MLIBC_THREAD_MUTEX_NORMAL);
- }
-
- // TODO: Other values aren't supported yet.
- __ensure(robust == __MLIBC_THREAD_MUTEX_STALLED);
- __ensure(protocol == __MLIBC_THREAD_PRIO_NONE);
- __ensure(pshared == __MLIBC_THREAD_PROCESS_PRIVATE);
-
- return 0;
-}
-
-int thread_mutex_destroy(struct __mlibc_mutex *mutex) {
- __ensure(!mutex->__mlibc_state);
- return 0;
-}
-
-int thread_mutex_lock(struct __mlibc_mutex *mutex) {
- unsigned int this_tid = mlibc::this_tid();
- unsigned int expected = 0;
- while(true) {
- if(!expected) {
- // Try to take the mutex here.
- if(__atomic_compare_exchange_n(&mutex->__mlibc_state,
- &expected, this_tid, false, __ATOMIC_ACQUIRE, __ATOMIC_ACQUIRE)) {
- __ensure(!mutex->__mlibc_recursion);
- mutex->__mlibc_recursion = 1;
- return 0;
- }
- }else{
- // If this (recursive) mutex is already owned by us, increment the recursion level.
- if((expected & mutex_owner_mask) == this_tid) {
- if(!(mutex->__mlibc_flags & mutexRecursive)) {
- if (mutex->__mlibc_flags & mutexErrorCheck)
- return EDEADLK;
- else
- mlibc::panicLogger() << "mlibc: pthread_mutex deadlock detected!"
- << frg::endlog;
- }
- ++mutex->__mlibc_recursion;
- return 0;
- }
-
- // Wait on the futex if the waiters flag is set.
- if(expected & mutex_waiters_bit) {
- int e = mlibc::sys_futex_wait((int *)&mutex->__mlibc_state, expected, nullptr);
-
- // If the wait returns EAGAIN, that means that the mutex_waiters_bit was just unset by
- // some other thread. In this case, we should loop back around.
- if (e && e != EAGAIN)
- mlibc::panicLogger() << "sys_futex_wait() failed with error code " << e << frg::endlog;
-
- // Opportunistically try to take the lock after we wake up.
- expected = 0;
- }else{
- // Otherwise we have to set the waiters flag first.
- unsigned int desired = expected | mutex_waiters_bit;
- if(__atomic_compare_exchange_n((int *)&mutex->__mlibc_state,
- reinterpret_cast<int*>(&expected), desired, false, __ATOMIC_RELAXED, __ATOMIC_RELAXED))
- expected = desired;
- }
- }
- }
-}
-
-int thread_mutex_unlock(struct __mlibc_mutex *mutex) {
- // Decrement the recursion level and unlock if we hit zero.
- __ensure(mutex->__mlibc_recursion);
- if(--mutex->__mlibc_recursion)
- return 0;
-
- auto flags = mutex->__mlibc_flags;
-
- // Reset the mutex to the unlocked state.
- auto state = __atomic_exchange_n(&mutex->__mlibc_state, 0, __ATOMIC_RELEASE);
-
- // After this point the mutex is unlocked, and therefore we cannot access its contents as it
- // may have been destroyed by another thread.
-
- unsigned int this_tid = mlibc::this_tid();
- if ((flags & mutexErrorCheck) && (state & mutex_owner_mask) != this_tid)
- return EPERM;
-
- if ((flags & mutexErrorCheck) && !(state & mutex_owner_mask))
- return EINVAL;
-
- __ensure((state & mutex_owner_mask) == this_tid);
-
- if(state & mutex_waiters_bit) {
- // Wake the futex if there were waiters. Since the mutex might not exist at this location
- // anymore, we must conservatively ignore EACCES and EINVAL which may occur as a result.
- int e = mlibc::sys_futex_wake((int *)&mutex->__mlibc_state);
- __ensure(e >= 0 || e == EACCES || e == EINVAL);
- }
-
- return 0;
-}
-
-int thread_mutexattr_init(struct __mlibc_mutexattr *attr) {
- attr->__mlibc_type = __MLIBC_THREAD_MUTEX_DEFAULT;
- attr->__mlibc_robust = __MLIBC_THREAD_MUTEX_STALLED;
- attr->__mlibc_pshared = __MLIBC_THREAD_PROCESS_PRIVATE;
- attr->__mlibc_protocol = __MLIBC_THREAD_PRIO_NONE;
- return 0;
-}
-
-int thread_mutexattr_destroy(struct __mlibc_mutexattr *attr) {
- memset(attr, 0, sizeof(*attr));
- return 0;
-}
-
-int thread_mutexattr_gettype(const struct __mlibc_mutexattr *__restrict attr, int *__restrict type) {
- *type = attr->__mlibc_type;
- return 0;
-}
-
-int thread_mutexattr_settype(struct __mlibc_mutexattr *attr, int type) {
- if (type != __MLIBC_THREAD_MUTEX_NORMAL && type != __MLIBC_THREAD_MUTEX_ERRORCHECK
- && type != __MLIBC_THREAD_MUTEX_RECURSIVE)
- return EINVAL;
-
- attr->__mlibc_type = type;
- return 0;
-}
-
-int thread_cond_init(struct __mlibc_cond *__restrict cond, const struct __mlibc_condattr *__restrict attr) {
- auto clock = attr ? attr->__mlibc_clock : CLOCK_REALTIME;
- auto pshared = attr ? attr->__mlibc_pshared : __MLIBC_THREAD_PROCESS_PRIVATE;
-
- cond->__mlibc_clock = clock;
- cond->__mlibc_flags = pshared;
-
- __atomic_store_n(&cond->__mlibc_seq, 1, __ATOMIC_RELAXED);
-
- return 0;
-}
-
-int thread_cond_destroy(struct __mlibc_cond *) {
- return 0;
-}
-
-int thread_cond_broadcast(struct __mlibc_cond *cond) {
- __atomic_fetch_add(&cond->__mlibc_seq, 1, __ATOMIC_RELEASE);
- if(int e = mlibc::sys_futex_wake((int *)&cond->__mlibc_seq); e)
- __ensure(!"sys_futex_wake() failed");
-
- return 0;
-}
-
-int thread_cond_timedwait(struct __mlibc_cond *__restrict cond, __mlibc_mutex *__restrict mutex,
- const struct timespec *__restrict abstime) {
- // TODO: pshared isn't supported yet.
- __ensure(cond->__mlibc_flags == 0);
-
- constexpr long nanos_per_second = 1'000'000'000;
- if (abstime && (abstime->tv_nsec < 0 || abstime->tv_nsec >= nanos_per_second))
- return EINVAL;
-
- auto seq = __atomic_load_n(&cond->__mlibc_seq, __ATOMIC_ACQUIRE);
-
- // TODO: handle locking errors and cancellation properly.
- while (true) {
- if (thread_mutex_unlock(mutex))
- __ensure(!"Failed to unlock the mutex");
-
- int e;
- if (abstime) {
- // Adjust for the fact that sys_futex_wait accepts a *timeout*, but
- // pthread_cond_timedwait accepts an *absolute time*.
- // Note: mlibc::sys_clock_get is available unconditionally.
- struct timespec now;
- if (mlibc::sys_clock_get(cond->__mlibc_clock, &now.tv_sec, &now.tv_nsec))
- __ensure(!"sys_clock_get() failed");
-
- struct timespec timeout;
- timeout.tv_sec = abstime->tv_sec - now.tv_sec;
- timeout.tv_nsec = abstime->tv_nsec - now.tv_nsec;
-
- // Check if abstime has already passed.
- if (timeout.tv_sec < 0 || (timeout.tv_sec == 0 && timeout.tv_nsec < 0)) {
- if (thread_mutex_lock(mutex))
- __ensure(!"Failed to lock the mutex");
- return ETIMEDOUT;
- } else if (timeout.tv_nsec >= nanos_per_second) {
- timeout.tv_nsec -= nanos_per_second;
- timeout.tv_sec++;
- __ensure(timeout.tv_nsec < nanos_per_second);
- } else if (timeout.tv_nsec < 0) {
- timeout.tv_nsec += nanos_per_second;
- timeout.tv_sec--;
- __ensure(timeout.tv_nsec >= 0);
- }
-
- e = mlibc::sys_futex_wait((int *)&cond->__mlibc_seq, seq, &timeout);
- } else {
- e = mlibc::sys_futex_wait((int *)&cond->__mlibc_seq, seq, nullptr);
- }
-
- if (thread_mutex_lock(mutex))
- __ensure(!"Failed to lock the mutex");
-
- // There are four cases to handle:
- // 1. e == 0: this indicates a (potentially spurious) wakeup. The value of
- // seq *must* be checked to distinguish these two cases.
- // 2. e == EAGAIN: this indicates that the value of seq changed before we
- // went to sleep. We don't need to check seq in this case.
- // 3. e == EINTR: a signal was delivered. The man page allows us to choose
- // whether to go to sleep again or to return 0, but we do the former
- // to match other libcs.
- // 4. e == ETIMEDOUT: this should only happen if abstime is set.
- if (e == 0) {
- auto cur_seq = __atomic_load_n(&cond->__mlibc_seq, __ATOMIC_ACQUIRE);
- if (cur_seq > seq)
- return 0;
- } else if (e == EAGAIN) {
- __ensure(__atomic_load_n(&cond->__mlibc_seq, __ATOMIC_ACQUIRE) > seq);
- return 0;
- } else if (e == EINTR) {
- continue;
- } else if (e == ETIMEDOUT) {
- __ensure(abstime);
- return ETIMEDOUT;
- } else {
- mlibc::panicLogger() << "sys_futex_wait() failed with error " << e << frg::endlog;
- }
- }
-}
-
-} // namespace mlibc