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// Copyright 2021 The Pigweed Authors
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.
#include "pw_sync/interrupt_spin_lock.h"
#include "RTOS.h"
#include "pw_assert/check.h"
namespace pw::sync {
void InterruptSpinLock::lock() {
// Mask interrupts.
OS_IncDI();
// Disable task switching to ensure kernel APIs cannot switch to other tasks
// which could then end up deadlocking recursively on this same lock.
OS_SuspendAllTasks();
// We can't deadlock here so crash instead.
PW_DCHECK(!native_type_.locked,
"Recursive InterruptSpinLock::lock() detected");
native_type_.locked = true;
}
void InterruptSpinLock::unlock() {
native_type_.locked = false;
OS_ResumeAllSuspendedTasks(); // Restore task switching.
OS_DecRI(); // Restore interrupts.
}
} // namespace pw::sync