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* Copyright (c) 2018 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#ifndef _KSWAP_H
#define _KSWAP_H
#include <ksched.h>
#include <kernel_arch_func.h>
#ifdef CONFIG_TIMESLICING
extern void _update_time_slice_before_swap(void);
#else
#define _update_time_slice_before_swap() /**/
#endif
#ifdef CONFIG_STACK_SENTINEL
extern void _check_stack_sentinel(void);
#else
#define _check_stack_sentinel() /**/
#endif
/* In SMP, the irq_lock() is a spinlock which is implicitly released
* and reacquired on context switch to preserve the existing
* semantics. This means that whenever we are about to return to a
* thread (via either _Swap() or interrupt/exception return!) we need
* to restore the lock state to whatever the thread's counter
* expects.
*/
void _smp_reacquire_global_lock(struct k_thread *thread);
void _smp_release_global_lock(struct k_thread *thread);
/* context switching and scheduling-related routines */
#ifdef CONFIG_USE_SWITCH
/* New style context switching. _arch_switch() is a lower level
* primitive that doesn't know about the scheduler or return value.
* Needed for SMP, where the scheduler requires spinlocking that we
* don't want to have to do in per-architecture assembly.
*/
static inline unsigned int _Swap(unsigned int key)
{
struct k_thread *new_thread, *old_thread;
int ret = 0;
#ifdef CONFIG_EXECUTION_BENCHMARKING
extern void read_timer_start_of_swap(void);
read_timer_start_of_swap();
#endif
old_thread = _current;
_check_stack_sentinel();
_update_time_slice_before_swap();
#ifdef CONFIG_TRACING
sys_trace_thread_switched_out();
#endif
new_thread = _get_next_ready_thread();
if (new_thread != old_thread) {
old_thread->swap_retval = -EAGAIN;
#ifdef CONFIG_SMP
_current_cpu->swap_ok = 0;
new_thread->base.cpu = _arch_curr_cpu()->id;
_smp_release_global_lock(new_thread);
#endif
_current = new_thread;
_arch_switch(new_thread->switch_handle,
&old_thread->switch_handle);
ret = _current->swap_retval;
}
#ifdef CONFIG_TRACING
sys_trace_thread_switched_in();
#endif
irq_unlock(key);
return ret;
}
#else /* !CONFIG_USE_SWITCH */
extern unsigned int __swap(unsigned int key);
static inline unsigned int _Swap(unsigned int key)
{
unsigned int ret;
_check_stack_sentinel();
_update_time_slice_before_swap();
#ifdef CONFIG_TRACING
sys_trace_thread_switched_out();
#endif
ret = __swap(key);
#ifdef CONFIG_TRACING
sys_trace_thread_switched_in();
#endif
return ret;
}
#endif
#endif /* _KSWAP_H */
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