banan-os/kernel/include/kernel/Lock/SpinLock.h

140 lines
3.2 KiB
C++

#pragma once
#include <BAN/Assert.h>
#include <BAN/Atomic.h>
#include <BAN/NoCopyMove.h>
#include <kernel/Processor.h>
#include <sys/types.h>
namespace Kernel
{
class SpinLock
{
BAN_NON_COPYABLE(SpinLock);
BAN_NON_MOVABLE(SpinLock);
public:
SpinLock() = default;
InterruptState lock()
{
auto state = Processor::get_interrupt_state();
Processor::set_interrupt_state(InterruptState::Disabled);
auto id = Processor::current_id().as_u32();
ASSERT(m_locker.load(BAN::MemoryOrder::memory_order_relaxed) != id);
auto expected = PROCESSOR_NONE.as_u32();
while (!m_locker.compare_exchange(expected, id, BAN::MemoryOrder::memory_order_acquire))
{
Processor::pause();
expected = PROCESSOR_NONE.as_u32();
}
return state;
}
bool try_lock_interrupts_disabled()
{
ASSERT(Processor::get_interrupt_state() == InterruptState::Disabled);
auto id = Processor::current_id().as_u32();
ASSERT(m_locker.load(BAN::MemoryOrder::memory_order_relaxed) != id);
auto expected = PROCESSOR_NONE.as_u32();
return m_locker.compare_exchange(expected, id, BAN::MemoryOrder::memory_order_acquire);
}
void unlock(InterruptState state)
{
ASSERT(Processor::get_interrupt_state() == InterruptState::Disabled);
ASSERT(current_processor_has_lock());
m_locker.store(PROCESSOR_NONE.as_u32(), BAN::MemoryOrder::memory_order_release);
Processor::set_interrupt_state(state);
}
bool current_processor_has_lock() const
{
return m_locker.load(BAN::MemoryOrder::memory_order_relaxed) == Processor::current_id().as_u32();
}
private:
BAN::Atomic<ProcessorID::value_type> m_locker { PROCESSOR_NONE.as_u32() };
};
class RecursiveSpinLock
{
BAN_NON_COPYABLE(RecursiveSpinLock);
BAN_NON_MOVABLE(RecursiveSpinLock);
public:
RecursiveSpinLock() = default;
InterruptState lock()
{
auto state = Processor::get_interrupt_state();
Processor::set_interrupt_state(InterruptState::Disabled);
auto id = Processor::current_id().as_u32();
ProcessorID::value_type expected = PROCESSOR_NONE.as_u32();
while (!m_locker.compare_exchange(expected, id, BAN::MemoryOrder::memory_order_acq_rel))
{
if (expected == id)
break;
Processor::pause();
expected = PROCESSOR_NONE.as_u32();
}
m_lock_depth++;
return state;
}
void unlock(InterruptState state)
{
ASSERT(Processor::get_interrupt_state() == InterruptState::Disabled);
ASSERT(current_processor_has_lock());
ASSERT(m_lock_depth > 0);
if (--m_lock_depth == 0)
m_locker.store(PROCESSOR_NONE.as_u32(), BAN::MemoryOrder::memory_order_release);
Processor::set_interrupt_state(state);
}
bool current_processor_has_lock() const
{
return m_locker.load(BAN::MemoryOrder::memory_order_relaxed) == Processor::current_id().as_u32();
}
private:
BAN::Atomic<ProcessorID::value_type> m_locker { PROCESSOR_NONE.as_u32() };
uint32_t m_lock_depth { 0 };
};
template<typename Lock>
class SpinLockGuard
{
BAN_NON_COPYABLE(SpinLockGuard);
BAN_NON_MOVABLE(SpinLockGuard);
public:
SpinLockGuard(Lock& lock)
: m_lock(lock)
{
m_state = m_lock.lock();
}
~SpinLockGuard()
{
m_lock.unlock(m_state);
}
private:
Lock& m_lock;
InterruptState m_state;
};
}