| /* SPDX-License-Identifier: GPL-2.0-only */ |
| |
| #include <assert.h> |
| #include <bootstate.h> |
| #include <console/console.h> |
| #include <smp/node.h> |
| #include <thread.h> |
| #include <timer.h> |
| #include <types.h> |
| |
| static u8 thread_stacks[CONFIG_STACK_SIZE * CONFIG_NUM_THREADS] __aligned(sizeof(uint64_t)); |
| static bool initialized; |
| |
| static void idle_thread_init(void); |
| |
| /* There needs to be at least one thread to run the ramstate state machine. */ |
| #define TOTAL_NUM_THREADS (CONFIG_NUM_THREADS + 1) |
| |
| /* Storage space for the thread structs .*/ |
| static struct thread all_threads[TOTAL_NUM_THREADS]; |
| |
| /* All runnable (but not running) and free threads are kept on their |
| * respective lists. */ |
| static struct thread *runnable_threads; |
| static struct thread *free_threads; |
| |
| static struct thread *active_thread; |
| |
| static inline int thread_can_yield(const struct thread *t) |
| { |
| return (t != NULL && t->can_yield > 0); |
| } |
| |
| static inline void set_current_thread(struct thread *t) |
| { |
| assert(boot_cpu()); |
| active_thread = t; |
| } |
| |
| static inline struct thread *current_thread(void) |
| { |
| if (!initialized || !boot_cpu()) |
| return NULL; |
| |
| return active_thread; |
| } |
| |
| static inline int thread_list_empty(struct thread **list) |
| { |
| return *list == NULL; |
| } |
| |
| static inline struct thread *pop_thread(struct thread **list) |
| { |
| struct thread *t; |
| |
| t = *list; |
| *list = t->next; |
| t->next = NULL; |
| return t; |
| } |
| |
| static inline void push_thread(struct thread **list, struct thread *t) |
| { |
| t->next = *list; |
| *list = t; |
| } |
| |
| static inline void push_runnable(struct thread *t) |
| { |
| push_thread(&runnable_threads, t); |
| } |
| |
| static inline struct thread *pop_runnable(void) |
| { |
| return pop_thread(&runnable_threads); |
| } |
| |
| static inline struct thread *get_free_thread(void) |
| { |
| struct thread *t; |
| |
| if (thread_list_empty(&free_threads)) |
| return NULL; |
| |
| t = pop_thread(&free_threads); |
| |
| /* Reset the current stack value to the original. */ |
| if (!t->stack_orig) |
| die("%s: Invalid stack value\n", __func__); |
| |
| t->stack_current = t->stack_orig; |
| |
| return t; |
| } |
| |
| static inline void free_thread(struct thread *t) |
| { |
| push_thread(&free_threads, t); |
| } |
| |
| /* The idle thread is ran whenever there isn't anything else that is runnable. |
| * It's sole responsibility is to ensure progress is made by running the timer |
| * callbacks. */ |
| __noreturn static enum cb_err idle_thread(void *unused) |
| { |
| /* This thread never voluntarily yields. */ |
| thread_coop_disable(); |
| while (1) |
| timers_run(); |
| } |
| |
| static void schedule(struct thread *t) |
| { |
| struct thread *current = current_thread(); |
| |
| /* If t is NULL need to find new runnable thread. */ |
| if (t == NULL) { |
| if (thread_list_empty(&runnable_threads)) |
| die("Runnable thread list is empty!\n"); |
| t = pop_runnable(); |
| } else { |
| /* current is still runnable. */ |
| push_runnable(current); |
| } |
| |
| if (t->handle) |
| t->handle->state = THREAD_STARTED; |
| |
| set_current_thread(t); |
| |
| switch_to_thread(t->stack_current, ¤t->stack_current); |
| } |
| |
| static void terminate_thread(struct thread *t, enum cb_err error) |
| { |
| if (t->handle) { |
| t->handle->error = error; |
| t->handle->state = THREAD_DONE; |
| } |
| |
| free_thread(t); |
| schedule(NULL); |
| } |
| |
| static void asmlinkage call_wrapper(void *unused) |
| { |
| struct thread *current = current_thread(); |
| enum cb_err error; |
| |
| error = current->entry(current->entry_arg); |
| |
| terminate_thread(current, error); |
| } |
| |
| struct block_boot_state { |
| boot_state_t state; |
| boot_state_sequence_t seq; |
| }; |
| |
| /* Block the provided state until thread is complete. */ |
| static void asmlinkage call_wrapper_block_state(void *arg) |
| { |
| struct block_boot_state *bbs = arg; |
| struct thread *current = current_thread(); |
| enum cb_err error; |
| |
| boot_state_block(bbs->state, bbs->seq); |
| error = current->entry(current->entry_arg); |
| boot_state_unblock(bbs->state, bbs->seq); |
| terminate_thread(current, error); |
| } |
| |
| /* Prepare a thread so that it starts by executing thread_entry(thread_arg). |
| * Within thread_entry() it will call func(arg). */ |
| static void prepare_thread(struct thread *t, struct thread_handle *handle, |
| enum cb_err (*func)(void *), void *arg, |
| asmlinkage void (*thread_entry)(void *), void *thread_arg) |
| { |
| /* Stash the function and argument to run. */ |
| t->entry = func; |
| t->entry_arg = arg; |
| |
| /* All new threads can yield by default. */ |
| t->can_yield = 1; |
| |
| /* Pointer used to publish the state of thread */ |
| t->handle = handle; |
| |
| arch_prepare_thread(t, thread_entry, thread_arg); |
| } |
| |
| static void thread_resume_from_timeout(struct timeout_callback *tocb) |
| { |
| struct thread *to; |
| |
| to = tocb->priv; |
| schedule(to); |
| } |
| |
| static void idle_thread_init(void) |
| { |
| struct thread *t; |
| |
| t = get_free_thread(); |
| |
| if (t == NULL) |
| die("No threads available for idle thread!\n"); |
| |
| /* Queue idle thread to run once all other threads have yielded. */ |
| prepare_thread(t, NULL, idle_thread, NULL, call_wrapper, NULL); |
| push_runnable(t); |
| } |
| |
| /* Don't inline this function so the timeout_callback won't have its storage |
| * space on the stack cleaned up before the call to schedule(). */ |
| static int __attribute__((noinline)) |
| thread_yield_timed_callback(struct timeout_callback *tocb, |
| unsigned int microsecs) |
| { |
| tocb->priv = current_thread(); |
| tocb->callback = thread_resume_from_timeout; |
| |
| if (timer_sched_callback(tocb, microsecs)) |
| return -1; |
| |
| /* The timer callback will wake up the current thread. */ |
| schedule(NULL); |
| return 0; |
| } |
| |
| static void *thread_alloc_space(struct thread *t, size_t bytes) |
| { |
| /* Allocate the amount of space on the stack keeping the stack |
| * aligned to the pointer size. */ |
| t->stack_current -= ALIGN_UP(bytes, sizeof(uintptr_t)); |
| |
| return (void *)t->stack_current; |
| } |
| |
| static void threads_initialize(void) |
| { |
| int i; |
| struct thread *t; |
| u8 *stack_top; |
| |
| if (initialized) |
| return; |
| |
| t = &all_threads[0]; |
| |
| set_current_thread(t); |
| |
| t->stack_orig = (uintptr_t)NULL; /* We never free the main thread */ |
| t->id = 0; |
| t->can_yield = 1; |
| |
| stack_top = &thread_stacks[CONFIG_STACK_SIZE]; |
| for (i = 1; i < TOTAL_NUM_THREADS; i++) { |
| t = &all_threads[i]; |
| t->stack_orig = (uintptr_t)stack_top; |
| t->id = i; |
| stack_top += CONFIG_STACK_SIZE; |
| free_thread(t); |
| } |
| |
| idle_thread_init(); |
| |
| initialized = 1; |
| } |
| |
| int thread_run(struct thread_handle *handle, enum cb_err (*func)(void *), void *arg) |
| { |
| struct thread *current; |
| struct thread *t; |
| |
| /* Lazy initialization */ |
| threads_initialize(); |
| |
| current = current_thread(); |
| |
| if (!thread_can_yield(current)) { |
| printk(BIOS_ERR, "%s() called from non-yielding context!\n", __func__); |
| return -1; |
| } |
| |
| t = get_free_thread(); |
| |
| if (t == NULL) { |
| printk(BIOS_ERR, "%s: No more threads!\n", __func__); |
| return -1; |
| } |
| |
| prepare_thread(t, handle, func, arg, call_wrapper, NULL); |
| schedule(t); |
| |
| return 0; |
| } |
| |
| int thread_run_until(struct thread_handle *handle, enum cb_err (*func)(void *), void *arg, |
| boot_state_t state, boot_state_sequence_t seq) |
| { |
| struct thread *current; |
| struct thread *t; |
| struct block_boot_state *bbs; |
| |
| /* This is a ramstage specific API */ |
| if (!ENV_RAMSTAGE) |
| dead_code(); |
| |
| /* Lazy initialization */ |
| threads_initialize(); |
| |
| current = current_thread(); |
| |
| if (!thread_can_yield(current)) { |
| printk(BIOS_ERR, "%s() called from non-yielding context!\n", __func__); |
| return -1; |
| } |
| |
| t = get_free_thread(); |
| |
| if (t == NULL) { |
| printk(BIOS_ERR, "%s: No more threads!\n", __func__); |
| return -1; |
| } |
| |
| bbs = thread_alloc_space(t, sizeof(*bbs)); |
| bbs->state = state; |
| bbs->seq = seq; |
| prepare_thread(t, handle, func, arg, call_wrapper_block_state, bbs); |
| schedule(t); |
| |
| return 0; |
| } |
| |
| int thread_yield(void) |
| { |
| return thread_yield_microseconds(0); |
| } |
| |
| int thread_yield_microseconds(unsigned int microsecs) |
| { |
| struct thread *current; |
| struct timeout_callback tocb; |
| |
| current = current_thread(); |
| |
| if (!thread_can_yield(current)) |
| return -1; |
| |
| if (thread_yield_timed_callback(&tocb, microsecs)) |
| return -1; |
| |
| return 0; |
| } |
| |
| void thread_coop_enable(void) |
| { |
| struct thread *current; |
| |
| current = current_thread(); |
| |
| if (current == NULL) |
| return; |
| |
| assert(current->can_yield <= 0); |
| |
| current->can_yield++; |
| } |
| |
| void thread_coop_disable(void) |
| { |
| struct thread *current; |
| |
| current = current_thread(); |
| |
| if (current == NULL) |
| return; |
| |
| current->can_yield--; |
| } |
| |
| enum cb_err thread_join(struct thread_handle *handle) |
| { |
| struct stopwatch sw; |
| struct thread *current = current_thread(); |
| |
| assert(handle); |
| assert(current); |
| assert(current->handle != handle); |
| |
| if (handle->state == THREAD_UNINITIALIZED) |
| return CB_ERR_ARG; |
| |
| printk(BIOS_SPEW, "waiting for thread\n"); |
| |
| stopwatch_init(&sw); |
| |
| while (handle->state != THREAD_DONE) |
| assert(thread_yield() == 0); |
| |
| printk(BIOS_SPEW, "took %lu us\n", stopwatch_duration_usecs(&sw)); |
| |
| return handle->error; |
| } |
| |
| void thread_mutex_lock(struct thread_mutex *mutex) |
| { |
| struct stopwatch sw; |
| |
| stopwatch_init(&sw); |
| |
| while (mutex->locked) |
| assert(thread_yield() == 0); |
| mutex->locked = true; |
| |
| printk(BIOS_SPEW, "took %lu us to acquire mutex\n", stopwatch_duration_usecs(&sw)); |
| } |
| |
| void thread_mutex_unlock(struct thread_mutex *mutex) |
| { |
| assert(mutex->locked); |
| mutex->locked = 0; |
| } |