| // Copyright 2016 The Fuchsia Authors |
| // Copyright (c) 2008-2015 Travis Geiselbrecht |
| // |
| // Use of this source code is governed by a MIT-style |
| // license that can be found in the LICENSE file or at |
| // https://opensource.org/licenses/MIT |
| |
| /** |
| * @file |
| * @brief Kernel threading |
| * |
| * This file is the core kernel threading interface. |
| * |
| * @defgroup thread Threads |
| * @{ |
| */ |
| #include "kernel/thread.h" |
| |
| #include <assert.h> |
| #include <debug.h> |
| #include <inttypes.h> |
| #include <lib/arch/intrin.h> |
| #include <lib/counters.h> |
| #include <lib/fit/defer.h> |
| #include <lib/heap.h> |
| #include <lib/ktrace.h> |
| #include <lib/lazy_init/lazy_init.h> |
| #include <lib/version.h> |
| #include <lib/zircon-internal/macros.h> |
| #include <platform.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <zircon/errors.h> |
| #include <zircon/listnode.h> |
| #include <zircon/time.h> |
| #include <zircon/types.h> |
| |
| #include <arch/debugger.h> |
| #include <arch/exception.h> |
| #include <arch/interrupt.h> |
| #include <arch/ops.h> |
| #include <kernel/auto_preempt_disabler.h> |
| #include <kernel/cpu.h> |
| #include <kernel/dpc.h> |
| #include <kernel/lockdep.h> |
| #include <kernel/mp.h> |
| #include <kernel/percpu.h> |
| #include <kernel/scheduler.h> |
| #include <kernel/stats.h> |
| #include <kernel/thread.h> |
| #include <kernel/thread_lock.h> |
| #include <kernel/timer.h> |
| #include <ktl/algorithm.h> |
| #include <ktl/atomic.h> |
| #include <lk/main.h> |
| #include <lockdep/lockdep.h> |
| #include <object/process_dispatcher.h> |
| #include <object/thread_dispatcher.h> |
| #include <pretty/hexdump.h> |
| #include <vm/kstack.h> |
| #include <vm/vm.h> |
| #include <vm/vm_address_region.h> |
| #include <vm/vm_aspace.h> |
| |
| #include <ktl/enforce.h> |
| |
| #define LOCAL_TRACE 0 |
| |
| // kernel counters. |
| // The counters below never decrease. |
| // |
| // counts the number of Threads successfully created. |
| KCOUNTER(thread_create_count, "thread.create") |
| // counts the number of detached Threads that exited. Never decreases. |
| KCOUNTER(thread_detached_exit_count, "thread.detached_exit") |
| // counts the number of Threads joined. Never decreases. |
| KCOUNTER(thread_join_count, "thread.join") |
| // counts the number of calls to suspend() that succeeded. |
| KCOUNTER(thread_suspend_count, "thread.suspend") |
| // counts the number of calls to resume() that succeeded. |
| KCOUNTER(thread_resume_count, "thread.resume") |
| |
| // The global thread list. This is a lazy_init type, since initial thread code |
| // manipulates the list before global constructors are run. This is initialized by |
| // thread_init_early. |
| static lazy_init::LazyInit<Thread::List> thread_list; |
| |
| Thread::MigrateList Thread::migrate_list_; |
| |
| // master thread spinlock |
| MonitoredSpinLock thread_lock __CPU_ALIGN_EXCLUSIVE; |
| |
| const char* ToString(enum thread_state state) { |
| switch (state) { |
| case THREAD_INITIAL: |
| return "initial"; |
| case THREAD_READY: |
| return "ready"; |
| case THREAD_RUNNING: |
| return "running"; |
| case THREAD_BLOCKED: |
| return "blocked"; |
| case THREAD_BLOCKED_READ_LOCK: |
| return "blocked read lock"; |
| case THREAD_SLEEPING: |
| return "sleeping"; |
| case THREAD_SUSPENDED: |
| return "suspended"; |
| case THREAD_DEATH: |
| return "death"; |
| default: |
| return "[unknown]"; |
| } |
| } |
| |
| static void init_thread_lock_state(Thread* t) { |
| #if WITH_LOCK_DEP |
| lockdep::SystemInitThreadLockState(&t->lock_state()); |
| #endif |
| } |
| |
| void WaitQueueCollection::ThreadState::Block(Interruptible interruptible, zx_status_t status) { |
| blocked_status_ = status; |
| interruptible_ = interruptible; |
| Scheduler::Block(); |
| interruptible_ = Interruptible::No; |
| } |
| |
| void WaitQueueCollection::ThreadState::UnblockIfInterruptible(Thread* thread, zx_status_t status) { |
| if (interruptible_ == Interruptible::Yes) { |
| WaitQueue::UnblockThread(thread, status); |
| } |
| } |
| |
| void WaitQueueCollection::ThreadState::Unsleep(Thread* thread, zx_status_t status) { |
| blocked_status_ = status; |
| Scheduler::Unblock(thread); |
| } |
| |
| void WaitQueueCollection::ThreadState::UnsleepIfInterruptible(Thread* thread, zx_status_t status) { |
| if (interruptible_ == Interruptible::Yes) { |
| Unsleep(thread, status); |
| } |
| } |
| |
| void WaitQueueCollection::ThreadState::UpdatePriorityIfBlocked(Thread* thread, int priority, |
| PropagatePI propagate) { |
| if (blocking_wait_queue_) { |
| blocking_wait_queue_->PriorityChanged(thread, priority, propagate); |
| } |
| } |
| |
| WaitQueueCollection::ThreadState::~ThreadState() { |
| DEBUG_ASSERT(blocking_wait_queue_ == nullptr); |
| |
| // owned_wait_queues_ is a fbl:: list of unmanaged pointers. It will debug |
| // assert if it is not empty when it destructs; we do not need to do so |
| // here. |
| } |
| |
| // Default constructor/destructor. |
| Thread::Thread() {} |
| |
| Thread::~Thread() { |
| // At this point, the thread must not be on the global thread list or migrate |
| // list. |
| DEBUG_ASSERT(!thread_list_node_.InContainer()); |
| DEBUG_ASSERT(!migrate_list_node_.InContainer()); |
| } |
| |
| void Thread::set_name(ktl::string_view name) { |
| // |name| must fit in ZX_MAX_NAME_LEN bytes, minus 1 for the trailing NUL. |
| name = name.substr(0, ZX_MAX_NAME_LEN - 1); |
| memcpy(name_, name.data(), name.size()); |
| memset(name_ + name.size(), 0, ZX_MAX_NAME_LEN - name.size()); |
| } |
| |
| void init_thread_struct(Thread* t, const char* name) { |
| memset(t, 0, sizeof(Thread)); |
| |
| // Placement new to trigger any special construction requirements of the |
| // Thread structure. |
| // |
| // TODO(johngro): now that we have converted Thread over to C++, consider |
| // switching to using C++ constructors/destructors and new/delete to handle |
| // all of this instead of using init_thread_struct and free_thread_resources |
| new (t) Thread(); |
| |
| t->set_name(name); |
| init_thread_lock_state(t); |
| } |
| |
| void TaskState::Init(thread_start_routine entry, void* arg) { |
| entry_ = entry; |
| arg_ = arg; |
| } |
| |
| zx_status_t TaskState::Join(zx_time_t deadline) { |
| return retcode_wait_queue_.Block(deadline, Interruptible::No); |
| } |
| |
| void TaskState::WakeJoiners(zx_status_t status) { retcode_wait_queue_.WakeAll(status); } |
| |
| void Thread::Trampoline() { |
| // Release the thread lock that was implicitly held across the reschedule. |
| thread_lock.Release(); |
| arch_enable_ints(); |
| |
| Thread* ct = Thread::Current::Get(); |
| int ret = ct->task_state_.entry()(ct->task_state_.arg()); |
| |
| Thread::Current::Exit(ret); |
| } |
| |
| /** |
| * @brief Create a new thread |
| * |
| * This function creates a new thread. The thread is initially suspended, so you |
| * need to call thread_resume() to execute it. |
| * |
| * @param t If not nullptr, use the supplied Thread |
| * @param name Name of thread |
| * @param entry Entry point of thread |
| * @param arg Arbitrary argument passed to entry(). It can be null. |
| * in which case |user_thread| will be used. |
| * @param priority Execution priority for the thread. |
| * @param alt_trampoline If not nullptr, an alternate trampoline for the thread |
| * to start on. |
| * |
| * Thread priority is an integer from 0 (lowest) to 31 (highest). Some standard |
| * priorities are defined in <kernel/thread.h>: |
| * |
| * HIGHEST_PRIORITY |
| * DPC_PRIORITY |
| * HIGH_PRIORITY |
| * DEFAULT_PRIORITY |
| * LOW_PRIORITY |
| * IDLE_PRIORITY |
| * LOWEST_PRIORITY |
| * |
| * Stack size is set to DEFAULT_STACK_SIZE |
| * |
| * @return Pointer to thread object, or nullptr on failure. |
| */ |
| Thread* Thread::CreateEtc(Thread* t, const char* name, thread_start_routine entry, void* arg, |
| int priority, thread_trampoline_routine alt_trampoline) { |
| unsigned int flags = 0; |
| |
| if (!t) { |
| t = static_cast<Thread*>(memalign(alignof(Thread), sizeof(Thread))); |
| if (!t) { |
| return nullptr; |
| } |
| flags |= THREAD_FLAG_FREE_STRUCT; |
| } |
| |
| // assert that t is at least as aligned as the Thread is supposed to be |
| DEBUG_ASSERT(IS_ALIGNED(t, alignof(Thread))); |
| |
| init_thread_struct(t, name); |
| |
| t->task_state_.Init(entry, arg); |
| Scheduler::InitializeThread(t, priority); |
| |
| zx_status_t status = t->stack_.Init(); |
| if (status != ZX_OK) { |
| if (flags & THREAD_FLAG_FREE_STRUCT) { |
| free(t); |
| } |
| return nullptr; |
| } |
| |
| // save whether or not we need to free the thread struct and/or stack |
| t->flags_ = flags; |
| |
| if (likely(alt_trampoline == nullptr)) { |
| alt_trampoline = &Thread::Trampoline; |
| } |
| |
| // set up the initial stack frame |
| arch_thread_initialize(t, (vaddr_t)alt_trampoline); |
| |
| // add it to the global thread list |
| { |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| thread_list->push_front(t); |
| } |
| |
| kcounter_add(thread_create_count, 1); |
| return t; |
| } |
| |
| Thread* Thread::Create(const char* name, thread_start_routine entry, void* arg, int priority) { |
| return Thread::CreateEtc(nullptr, name, entry, arg, priority, nullptr); |
| } |
| |
| static void free_thread_resources(Thread* t) { |
| // free the thread structure itself. Manually trigger the struct's |
| // destructor so that DEBUG_ASSERTs present in the owned_wait_queues member |
| // get triggered. |
| bool thread_needs_free = t->free_struct(); |
| t->~Thread(); |
| if (thread_needs_free) { |
| free(t); |
| } |
| } |
| |
| /** |
| * @brief Make a suspended thread executable. |
| * |
| * This function is called to start a thread which has just been |
| * created with thread_create() or which has been suspended with |
| * thread_suspend(). It can not fail. |
| */ |
| void Thread::Resume() { |
| canary_.Assert(); |
| |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| |
| if (state() == THREAD_DEATH) { |
| // The thread is dead, resuming it is a no-op. |
| return; |
| } |
| |
| // Clear the suspend signal in case there is a pending suspend |
| signals_.fetch_and(~THREAD_SIGNAL_SUSPEND, ktl::memory_order_relaxed); |
| if (state() == THREAD_INITIAL || state() == THREAD_SUSPENDED) { |
| // Wake up the new thread, putting it in a run queue on a cpu. |
| Scheduler::Unblock(this); |
| } |
| |
| kcounter_add(thread_resume_count, 1); |
| } |
| |
| zx_status_t Thread::DetachAndResume() { |
| zx_status_t status = Detach(); |
| if (status != ZX_OK) { |
| return status; |
| } |
| Resume(); |
| return ZX_OK; |
| } |
| |
| /** |
| * @brief Suspend an initialized/ready/running thread |
| * |
| * @return ZX_OK on success, ZX_ERR_BAD_STATE if the thread is dead |
| */ |
| zx_status_t Thread::Suspend() { |
| canary_.Assert(); |
| DEBUG_ASSERT(!IsIdle()); |
| |
| // Disable preemption to defer rescheduling until the end of this scope. |
| AutoPreemptDisabler preempt_disable; |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| |
| if (state() == THREAD_DEATH) { |
| return ZX_ERR_BAD_STATE; |
| } |
| |
| signals_.fetch_or(THREAD_SIGNAL_SUSPEND, ktl::memory_order_relaxed); |
| |
| switch (state()) { |
| case THREAD_DEATH: |
| // This should be unreachable because this state was handled above. |
| panic("Unexpected thread state"); |
| case THREAD_INITIAL: |
| // Thread hasn't been started yet, add it to the run queue to transition |
| // properly through the INITIAL -> READY state machine first, then it |
| // will see the signal and go to SUSPEND before running user code. |
| // |
| // Though the state here is still INITIAL, the higher-level code has |
| // already executed ThreadDispatcher::Start() so all the userspace |
| // entry data has been initialized and will be ready to go as soon as |
| // the thread is unsuspended. |
| Scheduler::Unblock(this); |
| break; |
| case THREAD_READY: |
| // thread is ready to run and not blocked or suspended. |
| // will wake up and deal with the signal soon. |
| break; |
| case THREAD_RUNNING: |
| // thread is running (on another cpu) |
| // The following call is not essential. It just makes the |
| // thread suspension happen sooner rather than at the next |
| // timer interrupt or syscall. |
| mp_interrupt(MP_IPI_TARGET_MASK, cpu_num_to_mask(scheduler_state_.curr_cpu_)); |
| break; |
| case THREAD_SUSPENDED: |
| // thread is suspended already |
| break; |
| case THREAD_BLOCKED: |
| case THREAD_BLOCKED_READ_LOCK: |
| // thread is blocked on something and marked interruptible |
| wait_queue_state_.UnblockIfInterruptible(this, ZX_ERR_INTERNAL_INTR_RETRY); |
| break; |
| case THREAD_SLEEPING: |
| // thread is sleeping |
| wait_queue_state_.UnsleepIfInterruptible(this, ZX_ERR_INTERNAL_INTR_RETRY); |
| break; |
| } |
| |
| kcounter_add(thread_suspend_count, 1); |
| return ZX_OK; |
| } |
| |
| // Signal an exception on the current thread, to be handled when the |
| // current syscall exits. Unlike other signals, this is synchronous, in |
| // the sense that a thread signals itself. This exists primarily so that |
| // we can unwind the stack in order to get the state of userland's |
| // callee-saved registers at the point where userland invoked the |
| // syscall. |
| void Thread::Current::SignalPolicyException(uint32_t policy_exception_code, |
| uint32_t policy_exception_data) { |
| Thread* t = Thread::Current::Get(); |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| t->signals_.fetch_or(THREAD_SIGNAL_POLICY_EXCEPTION, ktl::memory_order_relaxed); |
| t->extra_policy_exception_code_ = policy_exception_code; |
| t->extra_policy_exception_data_ = policy_exception_data; |
| } |
| |
| void Thread::EraseFromListsLocked() { |
| thread_list->erase(*this); |
| if (migrate_list_node_.InContainer()) { |
| migrate_list_.erase(*this); |
| } |
| } |
| |
| zx_status_t Thread::Join(int* out_retcode, zx_time_t deadline) { |
| canary_.Assert(); |
| |
| { |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| |
| if (flags_ & THREAD_FLAG_DETACHED) { |
| // the thread is detached, go ahead and exit |
| return ZX_ERR_BAD_STATE; |
| } |
| |
| // wait for the thread to die |
| if (state() != THREAD_DEATH) { |
| zx_status_t status = task_state_.Join(deadline); |
| if (status != ZX_OK) { |
| return status; |
| } |
| } |
| |
| canary_.Assert(); |
| DEBUG_ASSERT(state() == THREAD_DEATH); |
| wait_queue_state_.AssertNotBlocked(); |
| |
| // save the return code |
| if (out_retcode) { |
| *out_retcode = task_state_.retcode(); |
| } |
| |
| // remove it from global lists |
| EraseFromListsLocked(); |
| |
| // Our canary_ will be cleared out in free_thread_resources, which |
| // explicitly invokes ~Thread. |
| } |
| |
| free_thread_resources(this); |
| |
| kcounter_add(thread_join_count, 1); |
| |
| return ZX_OK; |
| } |
| |
| zx_status_t Thread::Detach() { |
| canary_.Assert(); |
| |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| |
| // if another thread is blocked inside Join() on this thread, |
| // wake them up with a specific return code |
| task_state_.WakeJoiners(ZX_ERR_BAD_STATE); |
| |
| // if it's already dead, then just do what join would have and exit |
| if (state() == THREAD_DEATH) { |
| flags_ &= ~THREAD_FLAG_DETACHED; // makes sure Join continues |
| guard.Release(); |
| return Join(nullptr, 0); |
| } else { |
| flags_ |= THREAD_FLAG_DETACHED; |
| return ZX_OK; |
| } |
| } |
| |
| // called back in the DPC worker thread to free the stack and/or the thread structure |
| // itself for a thread that is exiting on its own. |
| void Thread::FreeDpc(Dpc* dpc) { |
| Thread* t = dpc->arg<Thread>(); |
| |
| t->canary_.Assert(); |
| DEBUG_ASSERT(t->state() == THREAD_DEATH); |
| |
| // grab and release the thread lock, which effectively serializes us with |
| // the thread that is queuing itself for destruction. |
| { |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| ktl::atomic_signal_fence(ktl::memory_order_seq_cst); |
| } |
| |
| free_thread_resources(t); |
| } |
| |
| __NO_RETURN void Thread::Current::ExitLocked(int retcode) TA_REQ(thread_lock) { |
| Thread* current_thread = Thread::Current::Get(); |
| |
| // create a dpc on the stack to queue up a free. |
| // must be put at top scope in this function to force the compiler to keep it from |
| // reusing the stack before the function exits |
| Dpc free_dpc; |
| |
| // enter the dead state |
| current_thread->set_death(); |
| current_thread->task_state_.set_retcode(retcode); |
| current_thread->CallMigrateFnLocked(Thread::MigrateStage::Exiting); |
| |
| // Make sure that we have released any wait queues we may have owned when we |
| // exited. TODO(johngro): Should we log a warning or take any other |
| // actions here? Normally, if a thread exits while owning a wait queue, it |
| // means that it exited while holding some sort of mutex or other |
| // synchronization object which will now never be released. This is usually |
| // Very Bad. If any of the OwnedWaitQueues are being used for user-mode |
| // futexes, who can say what the right thing to do is. In the case of a |
| // kernel mode mutex, it might be time to panic. |
| OwnedWaitQueue::DisownAllQueues(current_thread); |
| |
| // Disable preemption to keep from switching to the DPC thread until the final |
| // reschedule. |
| current_thread->preemption_state().PreemptDisable(); |
| |
| // if we're detached, then do our teardown here |
| if (current_thread->flags_ & THREAD_FLAG_DETACHED) { |
| kcounter_add(thread_detached_exit_count, 1); |
| |
| // remove it from global lists |
| current_thread->EraseFromListsLocked(); |
| |
| // queue a dpc to free the stack and, optionally, the thread structure |
| if (current_thread->stack_.base() || (current_thread->flags_ & THREAD_FLAG_FREE_STRUCT)) { |
| free_dpc = Dpc(&Thread::FreeDpc, current_thread); |
| zx_status_t status = free_dpc.QueueThreadLocked(); |
| DEBUG_ASSERT(status == ZX_OK); |
| } |
| } else { |
| // signal if anyone is waiting |
| current_thread->task_state_.WakeJoiners(ZX_OK); |
| } |
| |
| // Final reschedule. |
| Scheduler::RescheduleInternal(); |
| |
| panic("somehow fell through thread_exit()\n"); |
| } |
| |
| /** |
| * @brief Remove this thread from the scheduler, discarding |
| * its execution state. |
| * |
| * This is almost certainly not the function you want. In the general case, |
| * this is incredibly unsafe. |
| * |
| * This will free any resources allocated by thread_create. |
| */ |
| void Thread::Forget() { |
| { |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| |
| __UNUSED Thread* current_thread = Thread::Current::Get(); |
| DEBUG_ASSERT(current_thread != this); |
| |
| EraseFromListsLocked(); |
| } |
| |
| DEBUG_ASSERT(!wait_queue_state_.InWaitQueue()); |
| |
| free_thread_resources(this); |
| } |
| |
| /** |
| * @brief Terminate the current thread |
| * |
| * Current thread exits with the specified return code. |
| * |
| * This function does not return. |
| */ |
| void Thread::Current::Exit(int retcode) { |
| Thread* current_thread = Thread::Current::Get(); |
| |
| current_thread->canary_.Assert(); |
| DEBUG_ASSERT(current_thread->state() == THREAD_RUNNING); |
| DEBUG_ASSERT(!current_thread->IsIdle()); |
| |
| if (current_thread->user_thread_) { |
| DEBUG_ASSERT(!arch_ints_disabled() || !thread_lock.IsHeld()); |
| current_thread->user_thread_->ExitingCurrent(); |
| } |
| |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| Thread::Current::ExitLocked(retcode); |
| } |
| |
| void Thread::Current::Kill() { |
| Thread* current_thread = Thread::Current::Get(); |
| |
| current_thread->canary_.Assert(); |
| DEBUG_ASSERT(current_thread->state() == THREAD_RUNNING); |
| DEBUG_ASSERT(!current_thread->IsIdle()); |
| |
| current_thread->Kill(); |
| } |
| |
| // kill a thread |
| void Thread::Kill() { |
| canary_.Assert(); |
| |
| // Disable preemption to defer rescheduling until the end of this scope. |
| AutoPreemptDisabler preempt_disable; |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| |
| // deliver a signal to the thread. |
| signals_.fetch_or(THREAD_SIGNAL_KILL, ktl::memory_order_relaxed); |
| |
| // we are killing ourself |
| if (this == Thread::Current::Get()) { |
| return; |
| } |
| |
| // general logic is to wake up the thread so it notices it had a signal delivered to it |
| |
| switch (state()) { |
| case THREAD_INITIAL: |
| // thread hasn't been started yet. |
| // not really safe to wake it up, since it's only in this state because it's under |
| // construction by the creator thread. |
| break; |
| case THREAD_READY: |
| // thread is ready to run and not blocked or suspended. |
| // will wake up and deal with the signal soon. |
| // TODO: short circuit if it was blocked from user space |
| break; |
| case THREAD_RUNNING: |
| // thread is running (on another cpu). |
| // The following call is not essential. It just makes the |
| // thread termination happen sooner rather than at the next |
| // timer interrupt or syscall. |
| mp_interrupt(MP_IPI_TARGET_MASK, cpu_num_to_mask(scheduler_state_.curr_cpu_)); |
| break; |
| case THREAD_SUSPENDED: |
| // thread is suspended, resume it so it can get the kill signal |
| Scheduler::Unblock(this); |
| break; |
| case THREAD_BLOCKED: |
| case THREAD_BLOCKED_READ_LOCK: |
| // thread is blocked on something and marked interruptible |
| wait_queue_state_.UnblockIfInterruptible(this, ZX_ERR_INTERNAL_INTR_KILLED); |
| break; |
| case THREAD_SLEEPING: |
| // thread is sleeping |
| wait_queue_state_.UnsleepIfInterruptible(this, ZX_ERR_INTERNAL_INTR_KILLED); |
| break; |
| case THREAD_DEATH: |
| // thread is already dead |
| return; |
| } |
| } |
| |
| cpu_mask_t Thread::GetCpuAffinity() const { |
| canary_.Assert(); |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| return scheduler_state_.hard_affinity(); |
| } |
| |
| void Thread::SetCpuAffinity(cpu_mask_t affinity) { |
| canary_.Assert(); |
| DEBUG_ASSERT_MSG( |
| (affinity & mp_get_active_mask()) != 0, |
| "Attempted to set affinity mask to %#x, which has no overlap of active CPUs %#x.", affinity, |
| mp_get_active_mask()); |
| |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| |
| // set the affinity mask |
| scheduler_state_.hard_affinity_ = affinity; |
| |
| // let the scheduler deal with it |
| Scheduler::Migrate(this); |
| } |
| |
| void Thread::SetSoftCpuAffinity(cpu_mask_t affinity) { |
| canary_.Assert(); |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| |
| // set the affinity mask |
| scheduler_state_.soft_affinity_ = affinity; |
| |
| // let the scheduler deal with it |
| Scheduler::Migrate(this); |
| } |
| |
| cpu_mask_t Thread::GetSoftCpuAffinity() const { |
| canary_.Assert(); |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| return scheduler_state_.soft_affinity_; |
| } |
| |
| void Thread::Current::MigrateToCpu(const cpu_num_t target_cpu) { |
| Thread::Current::Get()->SetCpuAffinity(cpu_num_to_mask(target_cpu)); |
| } |
| |
| void Thread::SetMigrateFn(MigrateFn migrate_fn) { |
| canary_.Assert(); |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| SetMigrateFnLocked(ktl::move(migrate_fn)); |
| } |
| |
| void Thread::SetMigrateFnLocked(MigrateFn migrate_fn) { |
| DEBUG_ASSERT(!migrate_fn || !migrate_pending_); |
| canary_.Assert(); |
| // If |migrate_fn_| was previously set, remove |this| from |migrate_list_|. |
| if (migrate_fn_) { |
| migrate_list_.erase(*this); |
| } |
| |
| migrate_fn_ = ktl::move(migrate_fn); |
| |
| // Clear stale state when (un) setting the migrate fn. |
| // TODO(fxbug.dev/84078): Cleanup the migrate fn feature and associated state |
| // and clearly define and check invariants. |
| scheduler_state().next_cpu_ = INVALID_CPU; |
| migrate_pending_ = false; |
| |
| // If |migrate_fn_| is valid, add |this| to |migrate_list_|. |
| if (migrate_fn_) { |
| migrate_list_.push_front(this); |
| } |
| } |
| |
| void Thread::CallMigrateFnLocked(MigrateStage stage) { |
| if (unlikely(migrate_fn_)) { |
| switch (stage) { |
| case MigrateStage::Before: |
| if (!migrate_pending_) { |
| migrate_pending_ = true; |
| migrate_fn_(this, stage); |
| } |
| break; |
| |
| case MigrateStage::After: |
| if (migrate_pending_) { |
| migrate_pending_ = false; |
| migrate_fn_(this, stage); |
| } |
| break; |
| |
| case MigrateStage::Exiting: |
| migrate_fn_(this, stage); |
| break; |
| } |
| } |
| } |
| |
| void Thread::CallMigrateFnForCpuLocked(cpu_num_t cpu) { |
| for (auto& thread : migrate_list_) { |
| if (thread.state() != THREAD_READY && thread.scheduler_state().last_cpu_ == cpu) { |
| thread.CallMigrateFnLocked(Thread::MigrateStage::Before); |
| } |
| } |
| } |
| |
| bool Thread::CheckKillSignal() { |
| thread_lock.AssertHeld(); |
| |
| if (signals() & THREAD_SIGNAL_KILL) { |
| // Ensure we don't recurse into thread_exit. |
| DEBUG_ASSERT(state() != THREAD_DEATH); |
| return true; |
| } else { |
| return false; |
| } |
| } |
| |
| zx_status_t Thread::CheckKillOrSuspendSignal() const { |
| const auto current_signals = signals(); |
| if (unlikely(current_signals & THREAD_SIGNAL_KILL)) { |
| return ZX_ERR_INTERNAL_INTR_KILLED; |
| } |
| if (unlikely(current_signals & THREAD_SIGNAL_SUSPEND)) { |
| return ZX_ERR_INTERNAL_INTR_RETRY; |
| } |
| return ZX_OK; |
| } |
| |
| // finish suspending the current thread |
| void Thread::Current::DoSuspend() { |
| Thread* current_thread = Thread::Current::Get(); |
| |
| // Note: After calling this callback, we must not return without |
| // calling the callback with THREAD_USER_STATE_RESUME. That is |
| // because those callbacks act as barriers which control when it is |
| // safe for the zx_thread_read_state()/zx_thread_write_state() |
| // syscalls to access the userland register state kept by Thread. |
| if (current_thread->user_thread_) { |
| DEBUG_ASSERT(!arch_ints_disabled() || !thread_lock.IsHeld()); |
| current_thread->user_thread_->Suspending(); |
| } |
| |
| { |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| |
| // make sure we haven't been killed while the lock was dropped for the user callback |
| if (current_thread->CheckKillSignal()) { |
| guard.Release(); |
| Thread::Current::Exit(0); |
| } |
| |
| // Make sure the suspend signal wasn't cleared while we were running the |
| // callback. |
| if (current_thread->signals() & THREAD_SIGNAL_SUSPEND) { |
| current_thread->set_suspended(); |
| current_thread->signals_.fetch_and(~THREAD_SIGNAL_SUSPEND, ktl::memory_order_relaxed); |
| |
| // directly invoke the context switch, since we've already manipulated this thread's state |
| Scheduler::RescheduleInternal(); |
| |
| // If the thread was killed, we should not allow it to resume. We |
| // shouldn't call user_callback() with THREAD_USER_STATE_RESUME in |
| // this case, because there might not have been any request to |
| // resume the thread. |
| if (current_thread->CheckKillSignal()) { |
| guard.Release(); |
| Thread::Current::Exit(0); |
| } |
| } |
| } |
| |
| if (current_thread->user_thread_) { |
| DEBUG_ASSERT(!arch_ints_disabled() || !thread_lock.IsHeld()); |
| current_thread->user_thread_->Resuming(); |
| } |
| } |
| |
| bool Thread::SaveUserStateLocked() { |
| thread_lock.AssertHeld(); |
| DEBUG_ASSERT(this == Thread::Current::Get()); |
| DEBUG_ASSERT(user_thread_ != nullptr); |
| |
| if (user_state_saved_) { |
| return false; |
| } |
| user_state_saved_ = true; |
| arch_save_user_state(this); |
| return true; |
| } |
| |
| void Thread::RestoreUserStateLocked() { |
| thread_lock.AssertHeld(); |
| DEBUG_ASSERT(this == Thread::Current::Get()); |
| DEBUG_ASSERT(user_thread_ != nullptr); |
| |
| DEBUG_ASSERT(user_state_saved_); |
| user_state_saved_ = false; |
| arch_restore_user_state(this); |
| } |
| |
| ScopedThreadExceptionContext::ScopedThreadExceptionContext(const arch_exception_context_t* context) |
| : thread_(Thread::Current::Get()), context_(context) { |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| // It's possible that the context and state have been installed/saved earlier in the call chain. |
| // If so, then it's some other object's responsibilty to remove/restore. |
| need_to_remove_ = arch_install_exception_context(thread_, context_); |
| need_to_restore_ = thread_->SaveUserStateLocked(); |
| } |
| |
| ScopedThreadExceptionContext::~ScopedThreadExceptionContext() { |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| // Did we save the state? If so, then it's our job to restore it. |
| if (need_to_restore_) { |
| thread_->RestoreUserStateLocked(); |
| } |
| // Did we install the exception context? If so, then it's out job to remove it. |
| if (need_to_remove_) { |
| arch_remove_exception_context(thread_); |
| } |
| } |
| |
| // check for any pending signals and handle them |
| void Thread::Current::ProcessPendingSignals(GeneralRegsSource source, void* gregs) { |
| Thread* current_thread = Thread::Current::Get(); |
| if (likely(current_thread->signals() == 0)) { |
| return; |
| } |
| |
| // grab the thread lock so we can safely look at the signal mask |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| |
| // This thread is about to be killed, raise an exception, or become suspended. If this is a user |
| // thread, these are all debugger-visible actions. Save the general registers so that a debugger |
| // may access them. |
| const bool has_user_thread = current_thread->user_thread_ != nullptr; |
| if (has_user_thread) { |
| arch_set_suspended_general_regs(current_thread, source, gregs); |
| } |
| auto cleanup_suspended_general_regs = fit::defer([current_thread, has_user_thread]() { |
| if (has_user_thread) { |
| arch_reset_suspended_general_regs(current_thread); |
| } |
| }); |
| |
| if (current_thread->CheckKillSignal()) { |
| guard.Release(); |
| cleanup_suspended_general_regs.cancel(); |
| Thread::Current::Exit(0); |
| } |
| |
| // Report any policy exceptions raised by syscalls. |
| const unsigned int signals = current_thread->signals(); |
| if (has_user_thread && (signals & THREAD_SIGNAL_POLICY_EXCEPTION)) { |
| current_thread->signals_.fetch_and(~THREAD_SIGNAL_POLICY_EXCEPTION, ktl::memory_order_relaxed); |
| uint32_t policy_exception_code = current_thread->extra_policy_exception_code_; |
| uint32_t policy_exception_data = current_thread->extra_policy_exception_data_; |
| guard.Release(); |
| |
| zx_status_t status = |
| arch_dispatch_user_policy_exception(policy_exception_code, policy_exception_data); |
| if (status != ZX_OK) { |
| panic("arch_dispatch_user_policy_exception() failed: status=%d\n", status); |
| } |
| return; |
| } |
| |
| if (signals & THREAD_SIGNAL_SUSPEND) { |
| DEBUG_ASSERT(current_thread->state() == THREAD_RUNNING); |
| // This thread has been asked to suspend. If it has a user mode component we need to save the |
| // user register state prior to calling |thread_do_suspend| so that a debugger may access it |
| // while the thread is suspended. |
| if (has_user_thread) { |
| // The enclosing function, |thread_process_pending_signals|, is called at the boundary of |
| // kernel and user mode (e.g. just before returning from a syscall, timer interrupt, or |
| // architectural exception/fault). We're about the perform a save. If the save fails |
| // (returns false), then we likely have a mismatched save/restore pair, which is a bug. |
| const bool saved = current_thread->SaveUserStateLocked(); |
| DEBUG_ASSERT(saved); |
| guard.CallUnlocked([]() { Thread::Current::DoSuspend(); }); |
| if (saved) { |
| current_thread->RestoreUserStateLocked(); |
| } |
| } else { |
| // No user mode component so nothing to save. |
| guard.Release(); |
| Thread::Current::DoSuspend(); |
| } |
| } |
| } |
| |
| /** |
| * @brief Yield the cpu to another thread |
| * |
| * This function places the current thread at the end of the run queue |
| * and yields the cpu to another waiting thread (if any.) |
| * |
| * This function will return at some later time. Possibly immediately if |
| * no other threads are waiting to execute. |
| */ |
| void Thread::Current::Yield() { |
| __UNUSED Thread* current_thread = Thread::Current::Get(); |
| |
| current_thread->canary_.Assert(); |
| DEBUG_ASSERT(current_thread->state() == THREAD_RUNNING); |
| DEBUG_ASSERT(!arch_blocking_disallowed()); |
| |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| |
| CPU_STATS_INC(yields); |
| Scheduler::Yield(); |
| } |
| |
| /** |
| * @brief Preempt the current thread from an interrupt |
| * |
| * This function places the current thread at the head of the run |
| * queue and then yields the cpu to another thread. |
| */ |
| void Thread::Current::Preempt() { |
| Thread* current_thread = Thread::Current::Get(); |
| |
| current_thread->canary_.Assert(); |
| DEBUG_ASSERT(current_thread->state() == THREAD_RUNNING); |
| DEBUG_ASSERT(!arch_blocking_disallowed()); |
| |
| if (!current_thread->IsIdle()) { |
| // only track when a meaningful preempt happens |
| CPU_STATS_INC(irq_preempts); |
| } |
| |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| |
| Scheduler::Preempt(); |
| } |
| |
| /** |
| * @brief Reevaluate the run queue on the current cpu. |
| * |
| * This function places the current thread at the head of the run |
| * queue and then yields the cpu to another thread. Similar to |
| * thread_preempt, but intended to be used at non interrupt context. |
| */ |
| void Thread::Current::Reschedule() { |
| Thread* current_thread = Thread::Current::Get(); |
| |
| current_thread->canary_.Assert(); |
| DEBUG_ASSERT(current_thread->state() == THREAD_RUNNING); |
| DEBUG_ASSERT(!arch_blocking_disallowed()); |
| |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| |
| Scheduler::Reschedule(); |
| } |
| |
| void PreemptionState::FlushPending(Flush flush) { |
| // Early out to avoid unnecessarily taking the thread lock. This check races |
| // any potential flush due to context switch, however, the context switch can |
| // only clear bits that would have been flushed below, no new pending |
| // preemptions are possible in the mask bits indicated by |flush|. |
| if (likely(preempts_pending_ == 0)) { |
| return; |
| } |
| |
| const auto do_flush = [this, flush]() TA_REQ(thread_lock) { |
| // Recheck, pending preemptions could have been flushed by a context switch |
| // before interrupts were disabled. |
| const cpu_mask_t pending_mask = preempts_pending_; |
| |
| // If there is a pending local preemption the scheduler will take care of |
| // flushing all pending reschedules. |
| const cpu_mask_t current_cpu_mask = cpu_num_to_mask(arch_curr_cpu_num()); |
| if ((pending_mask & current_cpu_mask) != 0 && (flush & FlushLocal) != 0) { |
| // Clear the local preempt pending flag before calling preempt. Failure |
| // to do this can cause recursion during Scheduler::Preempt if any code |
| // (such as debug tracing code) attempts to disable and re-enable |
| // preemption during the scheduling operation. |
| preempts_pending_ &= ~current_cpu_mask; |
| Scheduler::Preempt(); |
| } else if ((flush & FlushRemote) != 0) { |
| // The current cpu is ignored by mp_reschedule if present in the mask. |
| mp_reschedule(pending_mask, 0); |
| preempts_pending_ &= current_cpu_mask; |
| } |
| }; |
| |
| // This method may be called with interrupts enabled or disabled and with or |
| // without holding the thread lock. |
| InterruptDisableGuard interrupt_disable; |
| if (thread_lock.IsHeld()) { |
| thread_lock.AssertHeld(); |
| do_flush(); |
| } else { |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| do_flush(); |
| } |
| } |
| |
| // timer callback to wake up a sleeping thread |
| void Thread::SleepHandler(Timer* timer, zx_time_t now, void* arg) { |
| Thread* t = static_cast<Thread*>(arg); |
| t->canary_.Assert(); |
| t->HandleSleep(timer, now); |
| } |
| |
| void Thread::HandleSleep(Timer* timer, zx_time_t now) { |
| // spin trylocking on the thread lock since the routine that set up the callback, |
| // thread_sleep_etc, may be trying to simultaneously cancel this timer while holding the |
| // thread_lock. |
| if (timer->TrylockOrCancel(&thread_lock)) { |
| return; |
| } |
| |
| if (state() != THREAD_SLEEPING) { |
| thread_lock.Release(); |
| return; |
| } |
| |
| // Unblock the thread, regardless of whether the sleep was interruptible. |
| wait_queue_state_.Unsleep(this, ZX_OK); |
| thread_lock.Release(); |
| } |
| |
| #define MIN_SLEEP_SLACK ZX_USEC(1) |
| #define MAX_SLEEP_SLACK ZX_SEC(1) |
| #define DIV_SLEEP_SLACK 10u |
| |
| // computes the amount of slack the thread_sleep timer will use |
| static zx_duration_t sleep_slack(zx_time_t deadline, zx_time_t now) { |
| if (deadline < now) { |
| return MIN_SLEEP_SLACK; |
| } |
| zx_duration_t slack = zx_time_sub_time(deadline, now) / DIV_SLEEP_SLACK; |
| return ktl::max(MIN_SLEEP_SLACK, ktl::min(slack, MAX_SLEEP_SLACK)); |
| } |
| |
| /** |
| * @brief Put thread to sleep; deadline specified in ns |
| * |
| * This function puts the current thread to sleep until the specified |
| * deadline has occurred. |
| * |
| * Note that this function could continue to sleep after the specified deadline |
| * if other threads are running. When the deadline occurrs, this thread will |
| * be placed at the head of the run queue. |
| * |
| * interruptible argument allows this routine to return early if the thread was signaled |
| * for something. |
| */ |
| zx_status_t Thread::Current::SleepEtc(const Deadline& deadline, Interruptible interruptible, |
| zx_time_t now) { |
| Thread* current_thread = Thread::Current::Get(); |
| |
| current_thread->canary_.Assert(); |
| DEBUG_ASSERT(current_thread->state() == THREAD_RUNNING); |
| DEBUG_ASSERT(!current_thread->IsIdle()); |
| DEBUG_ASSERT(!arch_blocking_disallowed()); |
| |
| // Skip all of the work if the deadline has already passed. |
| if (deadline.when() <= now) { |
| return ZX_OK; |
| } |
| |
| Timer timer; |
| |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| |
| // if we've been killed and going in interruptible, abort here |
| if (interruptible == Interruptible::Yes && unlikely((current_thread->signals()))) { |
| if (current_thread->signals() & THREAD_SIGNAL_KILL) { |
| return ZX_ERR_INTERNAL_INTR_KILLED; |
| } else { |
| return ZX_ERR_INTERNAL_INTR_RETRY; |
| } |
| } |
| |
| // set a one shot timer to wake us up and reschedule |
| timer.Set(deadline, &Thread::SleepHandler, current_thread); |
| |
| current_thread->set_sleeping(); |
| current_thread->wait_queue_state_.Block(interruptible, ZX_OK); |
| |
| // always cancel the timer, since we may be racing with the timer tick on other cpus |
| timer.Cancel(); |
| |
| return current_thread->wait_queue_state_.BlockedStatus(); |
| } |
| |
| zx_status_t Thread::Current::Sleep(zx_time_t deadline) { |
| const zx_time_t now = current_time(); |
| return SleepEtc(Deadline::no_slack(deadline), Interruptible::No, now); |
| } |
| |
| zx_status_t Thread::Current::SleepRelative(zx_duration_t delay) { |
| const zx_time_t now = current_time(); |
| const Deadline deadline = Deadline::no_slack(zx_time_add_duration(now, delay)); |
| return SleepEtc(deadline, Interruptible::No, now); |
| } |
| |
| zx_status_t Thread::Current::SleepInterruptible(zx_time_t deadline) { |
| const zx_time_t now = current_time(); |
| const TimerSlack slack(sleep_slack(deadline, now), TIMER_SLACK_LATE); |
| const Deadline slackDeadline(deadline, slack); |
| return SleepEtc(slackDeadline, Interruptible::Yes, now); |
| } |
| |
| /** |
| * @brief Return the number of nanoseconds a thread has been running for. |
| * |
| * This takes the thread_lock to ensure there are no races while calculating the |
| * runtime of the thread. |
| */ |
| zx_duration_t Thread::Runtime() const { |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| |
| zx_duration_t runtime = scheduler_state_.runtime_ns(); |
| if (state() == THREAD_RUNNING) { |
| zx_duration_t recent = |
| zx_time_sub_time(current_time(), scheduler_state_.last_started_running()); |
| runtime = zx_duration_add_duration(runtime, recent); |
| } |
| |
| return runtime; |
| } |
| |
| /** |
| * @brief Get the last CPU the given thread was run on, or INVALID_CPU if the |
| * thread has never run. |
| */ |
| cpu_num_t Thread::LastCpu() const { |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| return scheduler_state_.last_cpu_; |
| } |
| |
| /** |
| * @brief Get the last CPU the given thread was run on, or INVALID_CPU if the |
| * thread has never run. |
| */ |
| cpu_num_t Thread::LastCpuLocked() const { return scheduler_state_.last_cpu_; } |
| |
| /** |
| * @brief Construct a thread t around the current running state |
| * |
| * This should be called once per CPU initialization. It will create |
| * a thread that is pinned to the current CPU and running at the |
| * highest priority. |
| */ |
| void thread_construct_first(Thread* t, const char* name) { |
| DEBUG_ASSERT(arch_ints_disabled()); |
| |
| cpu_num_t cpu = arch_curr_cpu_num(); |
| |
| init_thread_struct(t, name); |
| t->set_detached(true); |
| |
| // Setup the scheduler state before directly manipulating its members. |
| Scheduler::InitializeThread(t, HIGHEST_PRIORITY); |
| t->scheduler_state().state_ = THREAD_RUNNING; |
| t->scheduler_state().curr_cpu_ = cpu; |
| t->scheduler_state().last_cpu_ = cpu; |
| t->scheduler_state().next_cpu_ = INVALID_CPU; |
| t->scheduler_state().hard_affinity_ = cpu_num_to_mask(cpu); |
| |
| // Start out with preemption disabled to avoid attempts to reschedule until |
| // threading is fulling enabled. This simplifies code paths shared between |
| // initialization and runtime (e.g. logging). Preemption is enabled when the |
| // idle thread for the current CPU is ready. |
| t->preemption_state().PreemptDisable(); |
| |
| arch_thread_construct_first(t); |
| |
| // Take care not to touch any locks when invoked by early init code that runs |
| // before global ctors are called. The thread_list is safe to mutate before |
| // global ctors are run. |
| if (lk_global_constructors_called()) { |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| thread_list->push_front(t); |
| } else { |
| [t]() TA_NO_THREAD_SAFETY_ANALYSIS { thread_list->push_front(t); }(); |
| } |
| } |
| |
| /** |
| * @brief Initialize threading system |
| * |
| * This function is called once, from kmain() |
| */ |
| void thread_init_early() { |
| DEBUG_ASSERT(arch_curr_cpu_num() == 0); |
| |
| // Initialize the thread list. This needs to be done manually now, since initial thread code |
| // manipulates the list before global constructors are run. |
| thread_list.Initialize(); |
| |
| // Init the boot percpu data. |
| percpu::InitializeBoot(); |
| |
| // create a thread to cover the current running state |
| Thread* t = &percpu::Get(0).idle_thread; |
| thread_construct_first(t, "bootstrap"); |
| } |
| |
| /** |
| * @brief Change name of current thread |
| */ |
| void Thread::Current::SetName(const char* name) { |
| Thread* current_thread = Thread::Current::Get(); |
| strlcpy(current_thread->name_, name, sizeof(current_thread->name_)); |
| } |
| |
| /** |
| * @brief Change priority of current thread |
| * |
| * Sets the thread to use the fair scheduling discipline using the given |
| * priority. |
| * |
| * See Thread::Create() for a discussion of priority values. |
| */ |
| void Thread::SetPriority(int priority) { |
| canary_.Assert(); |
| ASSERT(priority >= LOWEST_PRIORITY && priority <= HIGHEST_PRIORITY); |
| |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| Scheduler::ChangePriority(this, priority); |
| } |
| |
| /** |
| * @brief Change the deadline of current thread |
| * |
| * Sets the thread to use the deadline scheduling discipline using the given |
| * parameters. |
| * |
| * @param t The thread to set or change deadline scheduling parameters. |
| * @param params The deadline parameters to apply to the thread. |
| */ |
| void Thread::SetDeadline(const zx_sched_deadline_params_t& params) { |
| canary_.Assert(); |
| ASSERT(params.capacity > 0 && params.capacity <= params.relative_deadline && |
| params.relative_deadline <= params.period); |
| |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| Scheduler::ChangeDeadline(this, params); |
| } |
| |
| /** |
| * @brief Set the pointer to the user-mode thread, this will receive callbacks: |
| * ThreadDispatcher::Exiting() |
| * ThreadDispatcher::Suspending() / Resuming() |
| * |
| * This also caches the assocatiated koids of the thread and process |
| * dispatchers associated with the given ThreadDispatcher. |
| */ |
| void Thread::SetUsermodeThread(fbl::RefPtr<ThreadDispatcher> user_thread) { |
| canary_.Assert(); |
| DEBUG_ASSERT(state() == THREAD_INITIAL); |
| DEBUG_ASSERT(!user_thread_); |
| |
| user_thread_ = ktl::move(user_thread); |
| tid_ = user_thread_->get_koid(); |
| pid_ = user_thread_->process()->get_koid(); |
| |
| // All user mode threads are detached since they are responsible for cleaning themselves up. |
| // We can set this directly because we've checked that we are in the initial state. |
| flags_ |= THREAD_FLAG_DETACHED; |
| } |
| |
| /** |
| * @brief Become an idle thread |
| * |
| * This function marks the current thread as the idle thread -- the one which |
| * executes when there is nothing else to do. This function does not return. |
| * This thread is called once at boot on the first cpu. |
| */ |
| void Thread::Current::BecomeIdle() { |
| DEBUG_ASSERT(arch_ints_disabled()); |
| |
| Thread* t = Thread::Current::Get(); |
| cpu_num_t curr_cpu = arch_curr_cpu_num(); |
| |
| // Set our name |
| char name[16]; |
| snprintf(name, sizeof(name), "idle %u", curr_cpu); |
| Thread::Current::SetName(name); |
| |
| // Mark ourself as idle |
| t->flags_ |= THREAD_FLAG_IDLE; |
| Scheduler::InitializeThread(t, IDLE_PRIORITY); |
| |
| // Pin the thread on the current cpu and mark it as already running |
| t->scheduler_state_.last_cpu_ = curr_cpu; |
| t->scheduler_state_.curr_cpu_ = curr_cpu; |
| t->scheduler_state_.hard_affinity_ = cpu_num_to_mask(curr_cpu); |
| t->set_running(); |
| |
| // Cpu is active. |
| mp_set_curr_cpu_active(true); |
| mp_set_cpu_idle(curr_cpu); |
| |
| // Pend a preemption to ensure a reschedule. |
| arch_set_blocking_disallowed(true); |
| t->preemption_state().PreemptSetPending(); |
| arch_set_blocking_disallowed(false); |
| |
| // Enable preemption to start scheduling. Preemption is disabled during early |
| // threading startup on each CPU to prevent incidental thread wakeups (e.g. |
| // due to logging) from rescheduling on the local CPU before the idle thread |
| // is ready. |
| t->preemption_state().PreemptReenable(); |
| DEBUG_ASSERT(t->preemption_state().PreemptIsEnabled()); |
| |
| // We're now properly in the idle routine. Reenable interrupts and drop |
| // into the idle routine, never return. |
| arch_enable_ints(); |
| arch_idle_thread_routine(nullptr); |
| |
| __UNREACHABLE; |
| } |
| |
| /** |
| * @brief Create a thread around the current execution context, preserving |t|'s stack |
| * |
| * Prior to calling, |t->stack| must be properly constructed. See |vm_allocate_kstack|. |
| */ |
| void Thread::SecondaryCpuInitEarly() { |
| DEBUG_ASSERT(arch_ints_disabled()); |
| DEBUG_ASSERT(stack_.base() != 0); |
| DEBUG_ASSERT(IS_ALIGNED(this, alignof(Thread))); |
| |
| // At this point, the CPU isn't far enough along to allow threads to block. Set blocking |
| // disallowed until to catch bugs where code might block before we're ready. |
| arch_set_blocking_disallowed(true); |
| |
| percpu::InitializeSecondaryFinish(); |
| |
| // Save |this|'s stack because |thread_construct_first| will zero out the whole struct. |
| KernelStack stack = ktl::move(stack_); |
| |
| char name[16]; |
| snprintf(name, sizeof(name), "cpu_init %u", arch_curr_cpu_num()); |
| thread_construct_first(this, name); |
| |
| // Restore the stack. |
| stack_ = ktl::move(stack); |
| } |
| |
| /** |
| * @brief The last routine called on the secondary cpu's bootstrap thread. |
| */ |
| void thread_secondary_cpu_entry() { |
| DEBUG_ASSERT(arch_blocking_disallowed()); |
| |
| mp_set_curr_cpu_active(true); |
| |
| percpu::GetCurrent().dpc_queue.InitForCurrentCpu(); |
| |
| // Exit from our bootstrap thread, and enter the scheduler on this cpu |
| Thread::Current::Exit(0); |
| } |
| |
| /** |
| * @brief Create an idle thread for a secondary CPU |
| */ |
| Thread* Thread::CreateIdleThread(cpu_num_t cpu_num) { |
| DEBUG_ASSERT(cpu_num != 0 && cpu_num < SMP_MAX_CPUS); |
| |
| char name[16]; |
| snprintf(name, sizeof(name), "idle %u", cpu_num); |
| |
| Thread* t = Thread::CreateEtc(&percpu::Get(cpu_num).idle_thread, name, arch_idle_thread_routine, |
| nullptr, IDLE_PRIORITY, nullptr); |
| if (t == nullptr) { |
| return t; |
| } |
| t->flags_ |= THREAD_FLAG_IDLE | THREAD_FLAG_DETACHED; |
| t->scheduler_state_.hard_affinity_ = cpu_num_to_mask(cpu_num); |
| |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| Scheduler::UnblockIdle(t); |
| return t; |
| } |
| |
| /** |
| * @brief Return the name of the "owner" of the thread. |
| * |
| * Returns "kernel" if there is no owner. |
| */ |
| |
| void Thread::OwnerName(char (&out_name)[ZX_MAX_NAME_LEN]) { |
| if (user_thread_) { |
| user_thread_->process()->get_name(out_name); |
| return; |
| } |
| memcpy(out_name, "kernel", 7); |
| } |
| |
| static const char* thread_state_to_str(enum thread_state state) { |
| switch (state) { |
| case THREAD_INITIAL: |
| return "init"; |
| case THREAD_SUSPENDED: |
| return "susp"; |
| case THREAD_READY: |
| return "rdy"; |
| case THREAD_RUNNING: |
| return "run"; |
| case THREAD_BLOCKED: |
| case THREAD_BLOCKED_READ_LOCK: |
| return "blok"; |
| case THREAD_SLEEPING: |
| return "slep"; |
| case THREAD_DEATH: |
| return "deth"; |
| default: |
| return "unkn"; |
| } |
| } |
| |
| /** |
| * @brief Dump debugging info about the specified thread. |
| */ |
| void dump_thread_locked(Thread* t, bool full_dump) { |
| if (!t->canary().Valid()) { |
| dprintf(INFO, "dump_thread WARNING: thread at %p has bad magic\n", t); |
| } |
| |
| zx_duration_t runtime = t->scheduler_state().runtime_ns(); |
| if (t->state() == THREAD_RUNNING) { |
| zx_duration_t recent = |
| zx_time_sub_time(current_time(), t->scheduler_state().last_started_running()); |
| runtime = zx_duration_add_duration(runtime, recent); |
| } |
| |
| char oname[ZX_MAX_NAME_LEN]; |
| t->OwnerName(oname); |
| |
| if (full_dump) { |
| dprintf(INFO, "dump_thread: t %p (%s:%s)\n", t, oname, t->name()); |
| dprintf(INFO, |
| "\tstate %s, curr/last cpu %d/%d, hard_affinity %#x, soft_cpu_affinity %#x, " |
| "priority %d [%d,%d], remaining time slice %" PRIi64 "\n", |
| thread_state_to_str(t->state()), (int)t->scheduler_state().curr_cpu(), |
| (int)t->scheduler_state().last_cpu(), t->scheduler_state().hard_affinity(), |
| t->scheduler_state().soft_affinity(), t->scheduler_state().effective_priority(), |
| t->scheduler_state().base_priority(), t->scheduler_state().inherited_priority(), |
| t->scheduler_state().time_slice_ns()); |
| dprintf(INFO, "\truntime_ns %" PRIi64 ", runtime_s %" PRIi64 "\n", runtime, |
| runtime / 1000000000); |
| t->stack().DumpInfo(INFO); |
| dprintf(INFO, "\tentry %p, arg %p, flags 0x%x %s%s%s%s\n", t->task_state_.entry_, |
| t->task_state_.arg_, t->flags_, (t->flags_ & THREAD_FLAG_DETACHED) ? "Dt" : "", |
| (t->flags_ & THREAD_FLAG_FREE_STRUCT) ? "Ft" : "", |
| (t->flags_ & THREAD_FLAG_IDLE) ? "Id" : "", (t->flags_ & THREAD_FLAG_VCPU) ? "Vc" : ""); |
| |
| dprintf(INFO, "\twait queue %p, blocked_status %d, interruptible %s, wait queues owned %s\n", |
| t->wait_queue_state().blocking_wait_queue_, t->wait_queue_state().blocked_status_, |
| t->wait_queue_state().interruptible_ == Interruptible::Yes ? "yes" : "no", |
| t->wait_queue_state().owned_wait_queues_.is_empty() ? "no" : "yes"); |
| |
| dprintf(INFO, "\taspace %p\n", t->aspace_); |
| dprintf(INFO, "\tuser_thread %p, pid %" PRIu64 ", tid %" PRIu64 "\n", t->user_thread_.get(), |
| t->pid(), t->tid()); |
| arch_dump_thread(t); |
| } else { |
| printf("thr %p st %4s owq %d pri %2d [%d,%d] pid %" PRIu64 " tid %" PRIu64 " (%s:%s)\n", t, |
| thread_state_to_str(t->state()), !t->wait_queue_state().owned_wait_queues_.is_empty(), |
| t->scheduler_state().effective_priority_, t->scheduler_state().base_priority_, |
| t->scheduler_state().inherited_priority_, t->pid(), t->tid(), oname, t->name()); |
| } |
| } |
| |
| void dump_thread(Thread* t, bool full) { |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| dump_thread_locked(t, full); |
| } |
| |
| /** |
| * @brief Dump debugging info about all threads |
| */ |
| void dump_all_threads_locked(bool full) { |
| for (Thread& t : thread_list.Get()) { |
| if (!t.canary().Valid()) { |
| dprintf(INFO, "bad magic on thread struct %p, aborting.\n", &t); |
| hexdump(&t, sizeof(Thread)); |
| break; |
| } |
| dump_thread_locked(&t, full); |
| } |
| } |
| |
| void dump_all_threads(bool full) { |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| dump_all_threads_locked(full); |
| } |
| |
| void dump_thread_tid(zx_koid_t tid, bool full) { |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| dump_thread_tid_locked(tid, full); |
| } |
| |
| void dump_thread_tid_locked(zx_koid_t tid, bool full) { |
| for (Thread& t : thread_list.Get()) { |
| if (t.tid() != tid) { |
| continue; |
| } |
| |
| if (!t.canary().Valid()) { |
| dprintf(INFO, "bad magic on thread struct %p, aborting.\n", &t); |
| hexdump(&t, sizeof(Thread)); |
| break; |
| } |
| dump_thread_locked(&t, full); |
| } |
| } |
| |
| Thread* thread_id_to_thread_slow(zx_koid_t tid) { |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| for (Thread& t : thread_list.Get()) { |
| if (t.tid() == tid) { |
| return &t; |
| } |
| } |
| |
| return nullptr; |
| } |
| |
| /** @} */ |
| |
| // Used by ktrace at the start of a trace to ensure that all |
| // the running threads, processes, and their names are known |
| void ktrace_report_live_threads() { |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| for (Thread& t : thread_list.Get()) { |
| t.canary().Assert(); |
| ktrace_name(TAG_THREAD_NAME, static_cast<uint32_t>(t.tid()), static_cast<uint32_t>(t.pid()), |
| t.name(), /*always*/ true); |
| } |
| } |
| |
| void Thread::UpdateSchedulerStats(const RuntimeStats::SchedulerStats& stats) { |
| if (user_thread_) { |
| user_thread_->UpdateSchedulerStats(stats); |
| } |
| } |
| |
| namespace { |
| |
| // TODO(maniscalco): Consider moving this method to the KernelStack class. |
| // That's probably a better home for it. |
| zx_status_t ReadStack(Thread* thread, vaddr_t ptr, vaddr_t* out, size_t sz) { |
| if (!is_kernel_address(ptr) || (ptr < thread->stack().base()) || |
| (ptr > (thread->stack().top() - sz))) { |
| return ZX_ERR_NOT_FOUND; |
| } |
| memcpy(out, reinterpret_cast<const void*>(ptr), sz); |
| return ZX_OK; |
| } |
| |
| void GetBacktraceCommon(Thread* thread, vaddr_t fp, Backtrace& out_bt) { |
| // Be sure that all paths out of this function leave with |out_bt| either |
| // properly filled in or empty. |
| out_bt.reset(); |
| |
| // Without frame pointers, dont even try. The compiler should optimize out |
| // the body of all the callers if it's not present. |
| if (!WITH_FRAME_POINTERS) { |
| return; |
| } |
| |
| // Perhaps we don't yet have a thread context? |
| if (thread == nullptr) { |
| return; |
| } |
| |
| if (fp == 0) { |
| return; |
| } |
| |
| vaddr_t pc; |
| size_t n = 0; |
| for (; n < Backtrace::kMaxSize; n++) { |
| if (ReadStack(thread, fp + 8, &pc, sizeof(vaddr_t))) { |
| break; |
| } |
| out_bt.push_back(pc); |
| if (ReadStack(thread, fp, &fp, sizeof(vaddr_t))) { |
| break; |
| } |
| } |
| } |
| |
| } // namespace |
| |
| void Thread::Current::GetBacktrace(Backtrace& out_bt) { |
| auto fp = reinterpret_cast<vaddr_t>(__GET_FRAME(0)); |
| GetBacktraceCommon(Thread::Current::Get(), fp, out_bt); |
| } |
| |
| void Thread::Current::GetBacktrace(vaddr_t fp, Backtrace& out_bt) { |
| GetBacktraceCommon(Thread::Current::Get(), fp, out_bt); |
| } |
| |
| void Thread::GetBacktrace(Backtrace& out_bt) { |
| Guard<MonitoredSpinLock, IrqSave> guard{ThreadLock::Get(), SOURCE_TAG}; |
| |
| // Get the starting point if it's in a usable state. |
| vaddr_t fp = 0; |
| switch (state()) { |
| case THREAD_BLOCKED: |
| case THREAD_BLOCKED_READ_LOCK: |
| case THREAD_SLEEPING: |
| case THREAD_SUSPENDED: |
| // Thread is blocked, so ask the arch code to get us a starting point. |
| fp = arch_thread_get_blocked_fp(this); |
| break; |
| default: |
| // Not in a valid state, can't get a backtrace. Reset it so the caller |
| // doesn't inadvertently use a previous value. |
| out_bt.reset(); |
| return; |
| } |
| |
| GetBacktraceCommon(this, fp, out_bt); |
| } |