zephyr/kernel/smp.c

115 lines
2.3 KiB
C

/*
* Copyright (c) 2018 Intel corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <kernel.h>
#include <kernel_structs.h>
#include <spinlock.h>
#include <kswap.h>
#include <kernel_internal.h>
#ifdef CONFIG_SMP
static atomic_t global_lock;
static atomic_t start_flag;
unsigned int z_smp_global_lock(void)
{
unsigned int key = arch_irq_lock();
if (!_current->base.global_lock_count) {
while (!atomic_cas(&global_lock, 0, 1)) {
}
}
_current->base.global_lock_count++;
return key;
}
void z_smp_global_unlock(unsigned int key)
{
if (_current->base.global_lock_count) {
_current->base.global_lock_count--;
if (!_current->base.global_lock_count) {
atomic_clear(&global_lock);
}
}
arch_irq_unlock(key);
}
void z_smp_reacquire_global_lock(struct k_thread *thread)
{
if (thread->base.global_lock_count) {
arch_irq_lock();
while (!atomic_cas(&global_lock, 0, 1)) {
}
}
}
/* Called from within z_swap(), so assumes lock already held */
void z_smp_release_global_lock(struct k_thread *thread)
{
if (!thread->base.global_lock_count) {
atomic_clear(&global_lock);
}
}
extern k_thread_stack_t _interrupt_stack1[];
extern k_thread_stack_t _interrupt_stack2[];
extern k_thread_stack_t _interrupt_stack3[];
#if CONFIG_MP_NUM_CPUS > 1
static FUNC_NORETURN void smp_init_top(void *arg)
{
atomic_t *start_flag = arg;
/* Wait for the signal to begin scheduling */
while (!atomic_get(start_flag)) {
}
/* Switch out of a dummy thread. Trick cribbed from the main
* thread init. Should probably unify implementations.
*/
struct k_thread dummy_thread = {
.base.user_options = K_ESSENTIAL,
.base.thread_state = _THREAD_DUMMY,
};
arch_curr_cpu()->current = &dummy_thread;
smp_timer_init();
z_swap_unlocked();
CODE_UNREACHABLE;
}
#endif
void z_smp_init(void)
{
(void)atomic_clear(&start_flag);
#if defined(CONFIG_SMP) && CONFIG_MP_NUM_CPUS > 1
arch_start_cpu(1, _interrupt_stack1, CONFIG_ISR_STACK_SIZE,
smp_init_top, &start_flag);
#endif
#if defined(CONFIG_SMP) && CONFIG_MP_NUM_CPUS > 2
arch_start_cpu(2, _interrupt_stack2, CONFIG_ISR_STACK_SIZE,
smp_init_top, &start_flag);
#endif
#if defined(CONFIG_SMP) && CONFIG_MP_NUM_CPUS > 3
arch_start_cpu(3, _interrupt_stack3, CONFIG_ISR_STACK_SIZE,
smp_init_top, &start_flag);
#endif
(void)atomic_set(&start_flag, 1);
}
#endif /* CONFIG_SMP */