mirror of
https://github.com/SerenityOS/serenity
synced 2024-09-06 17:06:31 +00:00
98 lines
1.7 KiB
C++
98 lines
1.7 KiB
C++
#pragma once
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#include "Types.h"
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#ifdef SERENITY
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#include "i386.h"
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int sched_yield();
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#else
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#include <sched.h>
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typedef int InterruptDisabler;
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#endif
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//#define DEBUG_LOCKS
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void log_try_lock(const char*);
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void log_locked(const char*);
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void log_unlocked(const char*);
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namespace AK {
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static inline dword CAS(volatile dword* mem, dword newval, dword oldval)
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{
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dword ret;
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asm volatile(
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"cmpxchgl %2, %1"
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:"=a"(ret), "+m"(*mem)
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:"r"(newval), "0"(oldval)
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:"memory");
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return ret;
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}
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class SpinLock {
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public:
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SpinLock() { }
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~SpinLock() { }
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void lock(const char* func = nullptr)
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{
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(void)func;
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#ifdef DEBUG_LOCKS
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{
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InterruptDisabler dis;
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log_try_lock(func);
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}
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#endif
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for (;;) {
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if (CAS(&m_lock, 1, 0) == 0) {
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#ifdef DEBUG_LOCKS
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InterruptDisabler dis;
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log_locked(func);
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#endif
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return;
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}
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sched_yield();
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}
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}
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void unlock(const char* func = nullptr)
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{
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(void)func;
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// barrier();
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ASSERT(m_lock);
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m_lock = 0;
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#ifdef DEBUG_LOCKS
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InterruptDisabler dis;
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log_unlocked(func);
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#endif
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}
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void init()
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{
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m_lock = 0;
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}
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private:
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volatile dword m_lock { 0 };
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};
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class Locker {
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public:
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explicit Locker(SpinLock& l, const char* func) : m_lock(l), m_func(func) { lock(); }
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~Locker() { unlock(); }
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void unlock() { m_lock.unlock(m_func); }
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void lock() { m_lock.lock(m_func); }
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private:
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SpinLock& m_lock;
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const char* m_func { nullptr };
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};
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#define LOCKER(lock) Locker locker(lock, __FUNCTION__)
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}
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using AK::SpinLock;
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using AK::Locker;
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