96 lines
2.0 KiB
C
96 lines
2.0 KiB
C
/*
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* Excerpted from Linux 3.0: arch/x86/include/asm/spinlock.h
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*/
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#ifndef __HEADER_X86_COMMON_ARCH_LOCK
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#define __HEADER_X86_COMMON_ARCH_LOCK
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#include <ihk/cpu.h>
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//#define DEBUG_SPINLOCK
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#ifdef DEBUG_SPINLOCK
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int __kprintf(const char *format, ...);
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#endif
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typedef int ihk_spinlock_t;
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#define IHK_STATIC_SPINLOCK_FUNCS
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static void ihk_mc_spinlock_init(ihk_spinlock_t *lock)
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{
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*lock = 0;
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}
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#define SPIN_LOCK_UNLOCKED 0
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static void ihk_mc_spinlock_lock_noirq(ihk_spinlock_t *lock)
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{
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int inc = 0x00010000;
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int tmp;
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#if 0
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asm volatile("lock ; xaddl %0, %1\n"
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"movzwl %w0, %2\n\t"
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"shrl $16, %0\n\t"
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"1:\t"
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"cmpl %0, %2\n\t"
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"je 2f\n\t"
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"rep ; nop\n\t"
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"movzwl %1, %2\n\t"
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"jmp 1b\n"
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"2:"
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: "+Q" (inc), "+m" (*lock), "=r" (tmp) : : "memory", "cc");
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#endif
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#ifdef DEBUG_SPINLOCK
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__kprintf("[%d] trying to grab lock: 0x%lX\n",
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ihk_mc_get_processor_id(), lock);
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#endif
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asm volatile("lock; xaddl %0, %1\n"
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"movzwl %w0, %2\n\t"
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"shrl $16, %0\n\t"
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"1:\t"
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"cmpl %0, %2\n\t"
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"je 2f\n\t"
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"rep ; nop\n\t"
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"movzwl %1, %2\n\t"
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/* don't need lfence here, because loads are in-order */
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"jmp 1b\n"
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"2:"
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: "+r" (inc), "+m" (*lock), "=&r" (tmp)
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:
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: "memory", "cc");
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#ifdef DEBUG_SPINLOCK
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__kprintf("[%d] holding lock: 0x%lX\n", ihk_mc_get_processor_id(), lock);
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#endif
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}
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static unsigned long ihk_mc_spinlock_lock(ihk_spinlock_t *lock)
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{
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unsigned long flags;
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flags = cpu_disable_interrupt_save();
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ihk_mc_spinlock_lock_noirq(lock);
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return flags;
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}
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static void ihk_mc_spinlock_unlock_noirq(ihk_spinlock_t *lock)
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{
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asm volatile ("lock incw %0" : "+m"(*lock) : : "memory", "cc");
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}
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static void ihk_mc_spinlock_unlock(ihk_spinlock_t *lock, unsigned long flags)
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{
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ihk_mc_spinlock_unlock_noirq(lock);
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cpu_restore_interrupt(flags);
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#ifdef DEBUG_SPINLOCK
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__kprintf("[%d] released lock: 0x%lX\n", ihk_mc_get_processor_id(), lock);
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#endif
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}
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#endif
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