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Kernel/SMP: Make entering/leaving critical sections multi-processor safe

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By making these functions static we close a window where we could get
preempted after calling Processor::current() and move to another
processor.

Co-authored-by: Tom <tomut@yahoo.com>
This commit is contained in:
Andreas Kling 2021-08-10 01:16:08 +02:00
parent 369e3da6a2
commit 9babb92a4b
11 changed files with 82 additions and 53 deletions
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8
Kernel/Locking/SpinLock.h
View file

@ -24,7 +24,7 @@ public:
ALWAYS_INLINE u32 lock()
{
u32 prev_flags;
Processor::current().enter_critical(prev_flags);
Processor::enter_critical(prev_flags);
while (m_lock.exchange(1, AK::memory_order_acquire) != 0) {
Processor::wait_check();
}
@ -35,7 +35,7 @@ public:
{
VERIFY(is_locked());
m_lock.store(0, AK::memory_order_release);
Processor::current().leave_critical(prev_flags);
Processor::leave_critical(prev_flags);
}
[[nodiscard]] ALWAYS_INLINE bool is_locked() const
@ -64,7 +64,7 @@ public:
auto& proc = Processor::current();
FlatPtr cpu = FlatPtr(&proc);
u32 prev_flags;
proc.enter_critical(prev_flags);
Processor::enter_critical(prev_flags);
FlatPtr expected = 0;
while (!m_lock.compare_exchange_strong(expected, cpu, AK::memory_order_acq_rel)) {
if (expected == cpu)
@ -82,7 +82,7 @@ public:
VERIFY(m_lock.load(AK::memory_order_relaxed) == FlatPtr(&Processor::current()));
if (--m_recursions == 0)
m_lock.store(0, AK::memory_order_release);
Processor::current().leave_critical(prev_flags);
Processor::leave_critical(prev_flags);
}
[[nodiscard]] ALWAYS_INLINE bool is_locked() const