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#include <stdio.h>
#include "litmus.h"
#include "internal.h"
/* per real-time thread kernel <-> user space flags */
struct np_flag {
#define RT_PREEMPTIVE 0x2050 /* = NP */
#define RT_NON_PREEMPTIVE 0x4e50 /* = P */
unsigned short preemptivity;
#define RT_EXIT_NP_REQUESTED 0x5251 /* = RQ */
unsigned short request;
unsigned int ctr;
};
int register_np_flag(struct np_flag* flag);
int signal_exit_np(void);
static __thread struct np_flag np_flag;
int init_kernel_iface(void)
{
int ret;
np_flag.preemptivity = RT_PREEMPTIVE;
np_flag.ctr = 0;
ret = register_np_flag(&np_flag);
check("register_np_flag()");
return ret;
}
static inline void barrier(void)
{
__asm__ __volatile__("sfence": : :"memory");
}
void enter_np(void)
{
if (++np_flag.ctr == 1)
{
np_flag.request = 0;
barrier();
np_flag.preemptivity = RT_NON_PREEMPTIVE;
}
}
void exit_np(void)
{
if (--np_flag.ctr == 0)
{
np_flag.preemptivity = RT_PREEMPTIVE;
barrier();
if (np_flag.request == RT_EXIT_NP_REQUESTED)
signal_exit_np();
}
}
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