Kernel: Make RecursiveSpinLock thread safe

also SpinLock is now implemented with gcc builtins
This commit is contained in:
Bananymous 2023-05-29 19:38:09 +03:00
parent 0c316ebfb2
commit dd3f34cb2c
4 changed files with 35 additions and 39 deletions

View File

@ -69,7 +69,6 @@ if("${BANAN_ARCH}" STREQUAL "x86_64")
arch/x86_64/IDT.cpp
arch/x86_64/interrupts.S
arch/x86_64/MMU.cpp
arch/x86_64/SpinLock.S
arch/x86_64/Thread.S
)
elseif("${BANAN_ARCH}" STREQUAL "i386")

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@ -1,17 +0,0 @@
.global spinlock_lock_asm
spinlock_lock_asm:
lock; btsq $0, (%rdi)
jnc .done
.retry:
pause
testq $1, (%rdi)
jne .retry
lock; btsq $0, (%rdi)
jc .retry
.done:
ret
.global spinlock_unlock_asm
spinlock_unlock_asm:
movl $0, (%rdi)
ret

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@ -19,7 +19,7 @@ namespace Kernel
bool is_locked() const;
private:
int m_lock = 0;
volatile int m_lock = 0;
};
class RecursiveSpinLock
@ -34,7 +34,7 @@ namespace Kernel
bool is_locked() const;
private:
pid_t m_locker = 0;
pid_t m_locker = -1;
uint32_t m_lock_depth = 0;
SpinLock m_lock;
};

View File

@ -4,17 +4,16 @@
namespace Kernel
{
extern "C" void spinlock_lock_asm(int*);
extern "C" void spinlock_unlock_asm(int*);
void SpinLock::lock()
{
spinlock_lock_asm(&m_lock);
while (__sync_lock_test_and_set(&m_lock, 1))
while (m_lock)
__builtin_ia32_pause();
}
void SpinLock::unlock()
{
spinlock_unlock_asm(&m_lock);
__sync_lock_release(&m_lock);
}
bool SpinLock::is_locked() const
@ -24,35 +23,50 @@ namespace Kernel
void RecursiveSpinLock::lock()
{
// FIXME: is this thread safe?
if (m_locker == Scheduler::current_tid())
pid_t tid = Scheduler::current_tid();
while (true)
{
// Wait for us to be the locker or the lock being free
while (m_locker != -1 && m_locker != tid)
__builtin_ia32_pause();
m_lock.lock();
if (m_locker == tid)
{
m_lock_depth++;
break;
}
else
if (m_locker == -1)
{
m_lock.lock();
ASSERT(m_locker == 0);
m_locker = Scheduler::current_tid();
m_locker = tid;
m_lock_depth = 1;
break;
}
m_lock.unlock();
}
m_lock.unlock();
}
void RecursiveSpinLock::unlock()
{
m_lock.lock();
ASSERT(m_lock_depth > 0);
ASSERT(m_locker == Scheduler::current_tid());
m_lock_depth--;
if (m_lock_depth == 0)
{
m_locker = 0;
m_locker = -1;
m_lock.unlock();
}
}
bool RecursiveSpinLock::is_locked() const
{
return m_lock.is_locked();
return m_locker != -1;
}
}