mirror of
https://github.com/zephyrproject-rtos/zephyr
synced 2025-08-09 22:16:29 +00:00
42ed12a387
Currently thread abort doesn't work if a thread is currently scheduled on a different CPU, because we have no way of delivering an interrupt to the other CPU to force the issue. This patch adds a simple framework for an architecture to provide such an IPI, implements it for x86_64, and uses it to implement a spin loop in abort for the case where a thread is currently scheduled elsewhere. On SMP architectures (xtensa) where no such IPI is implemented, we fall back to waiting on an arbitrary interrupt to occur. This "works" for typical code (and all current tests), but of course it cannot be guaranteed on such an architecture that k_thread_abort() will return in finite time (e.g. the other thread on the other CPU might have taken a spinlock and entered an infinite loop, so it will never receive an interrupt to terminate itself)! On non-SMP architectures this patch changes no code paths at all. Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
115 lines
2.3 KiB
C
115 lines
2.3 KiB
C
/*
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* Copyright (c) 2018 Intel corporation
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <kernel.h>
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#include <kernel_structs.h>
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#include <spinlock.h>
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#include <kswap.h>
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#include <kernel_internal.h>
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#ifdef CONFIG_SMP
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static atomic_t global_lock;
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static atomic_t start_flag;
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unsigned int z_smp_global_lock(void)
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{
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unsigned int key = z_arch_irq_lock();
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if (!_current->base.global_lock_count) {
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while (!atomic_cas(&global_lock, 0, 1)) {
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}
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}
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_current->base.global_lock_count++;
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return key;
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}
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void z_smp_global_unlock(unsigned int key)
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{
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if (_current->base.global_lock_count) {
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_current->base.global_lock_count--;
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if (!_current->base.global_lock_count) {
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atomic_clear(&global_lock);
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}
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}
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z_arch_irq_unlock(key);
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}
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void z_smp_reacquire_global_lock(struct k_thread *thread)
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{
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if (thread->base.global_lock_count) {
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z_arch_irq_lock();
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while (!atomic_cas(&global_lock, 0, 1)) {
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}
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}
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}
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/* Called from within z_swap(), so assumes lock already held */
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void z_smp_release_global_lock(struct k_thread *thread)
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{
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if (!thread->base.global_lock_count) {
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atomic_clear(&global_lock);
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}
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}
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extern k_thread_stack_t _interrupt_stack1[];
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extern k_thread_stack_t _interrupt_stack2[];
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extern k_thread_stack_t _interrupt_stack3[];
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#if CONFIG_MP_NUM_CPUS > 1
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static void smp_init_top(int key, void *arg)
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{
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atomic_t *start_flag = arg;
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/* Wait for the signal to begin scheduling */
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while (!atomic_get(start_flag)) {
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}
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/* Switch out of a dummy thread. Trick cribbed from the main
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* thread init. Should probably unify implementations.
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*/
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struct k_thread dummy_thread = {
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.base.user_options = K_ESSENTIAL,
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.base.thread_state = _THREAD_DUMMY,
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};
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z_arch_curr_cpu()->current = &dummy_thread;
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smp_timer_init();
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z_swap_unlocked();
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CODE_UNREACHABLE;
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}
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#endif
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void smp_init(void)
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{
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(void)atomic_clear(&start_flag);
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#if defined(CONFIG_SMP) && CONFIG_MP_NUM_CPUS > 1
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z_arch_start_cpu(1, _interrupt_stack1, CONFIG_ISR_STACK_SIZE,
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smp_init_top, &start_flag);
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#endif
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#if defined(CONFIG_SMP) && CONFIG_MP_NUM_CPUS > 2
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z_arch_start_cpu(2, _interrupt_stack2, CONFIG_ISR_STACK_SIZE,
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smp_init_top, &start_flag);
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#endif
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#if defined(CONFIG_SMP) && CONFIG_MP_NUM_CPUS > 3
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z_arch_start_cpu(3, _interrupt_stack3, CONFIG_ISR_STACK_SIZE,
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smp_init_top, &start_flag);
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#endif
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(void)atomic_set(&start_flag, 1);
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}
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#endif /* CONFIG_SMP */
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