1 // Copyright 2023 The Pigweed Authors
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not
4 // use this file except in compliance with the License. You may obtain a copy of
5 // the License at
6 //
7 // https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
12 // License for the specific language governing permissions and limitations under
13 // the License.
14 #include "pw_thread/thread.h"
15
16 #include <zephyr/kernel.h>
17 #include <zephyr/spinlock.h>
18
19 #include "pw_assert/check.h"
20 #include "pw_preprocessor/compiler.h"
21 #include "pw_thread/id.h"
22 #include "pw_thread_zephyr/config.h"
23 #include "pw_thread_zephyr/context.h"
24 #include "pw_thread_zephyr/options.h"
25
26 using pw::thread::zephyr::Context;
27
28 namespace pw::thread {
29 namespace {
30
31 k_spinlock global_thread_done_lock;
32
33 } // namespace
34
ThreadEntryPoint(void * void_context_ptr,void *,void *)35 void Context::ThreadEntryPoint(void* void_context_ptr, void*, void*) {
36 Context& context = *static_cast<Context*>(void_context_ptr);
37
38 // Invoke the user's thread function. This may never return.
39 context.fn_();
40 context.fn_ = nullptr;
41
42 k_spinlock_key_t key = k_spin_lock(&global_thread_done_lock);
43 if (context.detached()) {
44 context.set_task_handle(nullptr);
45 } else {
46 // Defer cleanup to Thread's join() or detach().
47 context.set_thread_done();
48 }
49 k_spin_unlock(&global_thread_done_lock, key);
50 }
51
CreateThread(const zephyr::Options & options,DeprecatedOrNewThreadFn && thread_fn,Context * & native_type_out)52 void Context::CreateThread(const zephyr::Options& options,
53 DeprecatedOrNewThreadFn&& thread_fn,
54 Context*& native_type_out) {
55 PW_CHECK(options.static_context() != nullptr);
56
57 // Use the statically allocated context.
58 native_type_out = options.static_context();
59 // Can't use a context more than once.
60 PW_DCHECK_PTR_EQ(native_type_out->task_handle(), nullptr);
61 // Reset the state of the static context in case it was re-used.
62 native_type_out->set_detached(false);
63 native_type_out->set_thread_done(false);
64
65 native_type_out->set_thread_routine(std::move(thread_fn));
66 const k_tid_t task_handle =
67 k_thread_create(&native_type_out->thread_info(),
68 options.static_context()->stack(),
69 options.static_context()->available_stack_size(),
70 Context::ThreadEntryPoint,
71 options.static_context(),
72 nullptr,
73 nullptr,
74 options.priority(),
75 options.native_options(),
76 K_NO_WAIT);
77 PW_CHECK_NOTNULL(task_handle); // Ensure it succeeded.
78 native_type_out->set_task_handle(task_handle);
79 }
80
Thread(const thread::Options & facade_options,Function<void ()> && entry)81 Thread::Thread(const thread::Options& facade_options, Function<void()>&& entry)
82 : native_type_(nullptr) {
83 // Cast the generic facade options to the backend specific option of which
84 // only one type can exist at compile time.
85 auto options = static_cast<const zephyr::Options&>(facade_options);
86 Context::CreateThread(options, std::move(entry), native_type_);
87 }
88
Thread(const thread::Options & facade_options,ThreadRoutine entry,void * arg)89 Thread::Thread(const thread::Options& facade_options,
90 ThreadRoutine entry,
91 void* arg)
92 : native_type_(nullptr) {
93 auto options = static_cast<const zephyr::Options&>(facade_options);
94 Context::CreateThread(
95 options, DeprecatedFnPtrAndArg{entry, arg}, native_type_);
96 }
97
detach()98 void Thread::detach() {
99 PW_CHECK(joinable());
100
101 k_spinlock_key_t key = k_spin_lock(&global_thread_done_lock);
102 native_type_->set_detached();
103 const bool thread_done = native_type_->thread_done();
104
105 if (thread_done) {
106 // The task finished (hit end of Context::ThreadEntryPoint) before we
107 // invoked detach, clean up the task handle to allow the Context reuse.
108 native_type_->set_task_handle(nullptr);
109 } else {
110 // We're detaching before the task finished, defer cleanup to the task at
111 // the end of Context::ThreadEntryPoint.
112 }
113
114 k_spin_unlock(&global_thread_done_lock, key);
115
116 // Update to no longer represent a thread of execution.
117 native_type_ = nullptr;
118 }
119
join()120 void Thread::join() {
121 PW_CHECK(joinable());
122 PW_CHECK(this_thread::get_id() != get_id());
123
124 PW_CHECK_INT_EQ(0, k_thread_join(native_type_->task_handle_, K_FOREVER));
125
126 native_type_->set_task_handle(nullptr);
127
128 // Update to no longer represent a thread of execution.
129 native_type_ = nullptr;
130 }
131
132 } // namespace pw::thread
133