Files
mckernel/arch/x86_64/kernel/lock.c
2017-10-18 09:20:52 +09:00

51 lines
1.0 KiB
C

/**
* \file lock.c
* License details are found in the file LICENSE.
* \brief
* Spin lock.
* \author Taku Shimosawa <shimosawa@is.s.u-tokyo.ac.jp> \par
* Copyright (C) 2011 - 2012 Taku Shimosawa
*/
/*
* HISTORY
*/
#include <ihk/lock.h>
#if 0
void ihk_mc_spinlock_init(ihk_spinlock_t *lock)
{
*lock = 0;
}
unsigned long ihk_mc_spinlock_lock(ihk_spinlock_t *lock)
{
int inc = 0x00010000;
int tmp;
unsigned long flags;
flags = cpu_disable_interrupt_save();
asm volatile("lock ; xaddl %0, %1\n"
"movzwl %w0, %2\n\t"
"shrl $16, %0\n\t"
"1:\t"
"cmpl %0, %2\n\t"
"je 2f\n\t"
"rep ; nop\n\t"
"movzwl %1, %2\n\t"
"jmp 1b\n"
"2:"
: "+Q" (inc), "+m" (*lock), "=r" (tmp) : : "memory", "cc");
return flags;
}
void ihk_mc_spinlock_unlock(ihk_spinlock_t *lock, unsigned long flags)
{
asm volatile ("lock incw %0" : "+m"(*lock) : : "memory", "cc");
cpu_restore_interrupt(flags);
}
#endif