kernel/spinlock.c


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#define FOOLOS_MODULE_NAME "spinlock"

#include "lib/logger/log.h"
#include "lib/int/stdint.h"
#include "x86.h"

// https://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html

typedef uint8_t spinlock;

volatile spinlock spinlocks[16];


void init_spinlocks()
{
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"Initializing spinlocks at 0x%08X ",spinlocks);
    for(int i=0;i<16;i++)spinlocks[i]=0;
}

volatile void lock_spin(int i)
{

    spinlock *addr=spinlocks+i;
//    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"locking %d (0x%08X)",i,addr);
    
    while(x86_xchg(addr,1));
}

void lock_release(int i)
{

//    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"unlocking %d",i);
    spinlock *addr=spinlocks+i;

    asm("movb $0,%0"::"m"(*addr));

}